A 108GS/s track-and-hold amplifier manufactured in a 55nm SiGe BiCMOS technology achieves 40GHz bandwidth with THD and SFDR of -49 dB and 55 dB, respectively. This performance is made possible by the use of a new MOS-HBT quasi-CML switch operating in class-AB mode, which results in an overall power consumption of 87 mW from 2.5V and 1.8V power supplies, respectively. The circuit targets time-interleaved ADC front-ends in next generation 64Gbaud fiber-optic receivers.

A high speed high dynamic range track-and-hold amplifier (THA) using 0.18 μm SiGe process is presented in this paper. A differential feedthrough cancellation technique is proposed to enhance the hold-mode isolation and linearity of the THA. The measured spurious free dynamic range (SFDR) is up to 55 dB with a sampling rate of 16 GS/s. The measured input bandwidth is up to 8 GHz with a hold-mode of isolation of higher than 50 dB. The total DC power consumption is 132 mW with a supply voltage of 2.5 V. The chip size is 1.3×0.89 mm2. As compared to the advanced silicon-based THAs, this work features high isolation, high speed, low dc power, good SFDR and linearity.

An ultra-broadband 2:1 analog-multiplexer (A-MUX) module has been developed for optical communications systems with a high symbol rate. The A-MUX IC was designed and fabricated using InP HBTs, which have a peak ft and fmax of 290 and 320 GHz, respectively. The A-MUX module has a through bandwidth of over 50 GHz and operates at a clock rate of up to 50 GHz, leading to 100-GS/s operation. Its power consumption is as small as 0.5 W. In addition, we devised a novel method to double the bandwidth of DACs using the A-MUX. We succeeded in generating an 80-Gbaud (160-Gb/s) Nyquist PAM4 signal based on two 20-GHz-bandwidth sub-DACs and this A-MUX.

This report presents a differential linear amplifier for multilevel transmissions at a high-symbol rate. We designed and fabricated this amplifier by using newly developed 0.25-μm InP DHBT technology, which yields a peak ft and fmax of over 400 GHz. This amplifier consists of a lumped variable-gain amplifier and a distributed output buffer for achieving a large gain control range and ultra-broadband performance. The -3 dB bandwidth and the differential gain are over 67 GHz and 10.7 dB, respectively. The output return loss is better than -10 dB up to 63 GHz. In addition to the ultra-broadband characteristics, a nearly 10-dB variable gain range was obtained. The amplifier provides a clear output waveform at symbol rates up to 100 Gbaud and 56 Gbaud with a NRZ signal and a PAM4 signal, respectively.

This paper reports the design and measurement results of a 1-tap feed-forward based analog equalizer, mainly designed with differential pair amplifier cells composed of Indium Phosphide (InP) heterojunction bipolar transistors. This analog equalizer exhibits a maximal peaking frequency and amplitude of 50 GHz and 12 dB respectively. Large signal measurements demonstrated an equalization at 100 Gb/s of a 3m-long 1.85-mm-connector coaxial cable, which represents a lossy channel of 20 dB at 50 GHz. To the authors' knowledge, this is the first analog equalizer reported with an equalization capability demonstrated at 100 Gb/s

A new full wave method based on circuit analysis is presented in this paper for the electromagnetic modeling of a split-cylinder resonator. First, the circuit analysis has been used for the characterization of a few networks of one, two and three ports, and then the mode-matching method is applied to calculate the admittance matrix of the structure. The method has been applied to the accurate determination of dielectric properties and it has been compared and validated by data from the literature. With this new method, the use of higher order modes allows measuring dielectric properties at higher frequencies, and also to obtain accurate results with less computational cost and more flexibility than other methods.

Microwave heating is one of the key technologies in medicine such as sterilization, synthesis of pharmacy and also uses in diagnostic and treatment. In application, it is necessary to obtain temperature dependent complex permittivity of material. For accurate measurement, one way is to apply a cylindrical cavity resonator. To apply microwave heating using the cavity resonator, it becomes possible to measure the temperature dependent permittivity of liquid material. In this study, TM010 cylindrical cavity resonator is designed of 2.45GHz band and developed the system to measure complex permittivity of liquid material in various temperatures. The cylindrical cavity resonator allows high microwaves power excitation and it can heat the sample dynamically with the measurement. The characteristics of the material as the temperature are measured by measuring transmission coefficient of the cylindrical cavity resonator with high power transmission.

This paper presents the description and theory of the novel amplitude-locked loop (ALL) circuit to support RF energy solutions as well as RF plasma and microwave heating applications. This analog control circuit includes hot S-parameter measurements to lock to the best S11-value in the 2.45 GHz ISM band. The necessary architecture including a new amplitude discriminator circuit is presented in detail. The second part of the paper describes hardware solutions, one with discrete integrated circuits and the current solution, which is fully integrated in a C11N CMOS-IC. These ALL solutions were tested in low speed applications (e.g. lamps) and high speed systems (e.g. spark plugs). The measurement results of the ALL hardware solutions wind up this paper. These measurement results exemplify the very good quality of this novel amplitude-locked loop circuit for different dynamic loads

An L-Band high power and efficient solid state power amplifier (SSPA) designed for the European satellite navigation system (i.e., Galileo) is presented. The developed SSPA, based on European Gallium Nitride (GaN) technology, comprises all the circuits required to interface the module with the satellite bus (i.e., a Power Supply Unit, PSU), and to control its functionalities by remote telecomand and telemetry (i.e., an Electronic Power Conditioner unit, EPC). The Radio frequency Unit (RFU) together with the PSU and EPC are accommodated in a single box with limited volume and mass. In continuous wave operating mode, the SSPA delivers an output power higher than 300W at less than 3dB of gain compression in the whole E1-Band (i.e., center frequency f0=1.575 GHz). Moreover, the demonstrated gain and power added efficiency, including the power dissipated by the PSU and EPC, are higher than 65dB and 44%, respectively.

A high pressure short time heat treatment is required for improvement of fluid properties of viscous raw oil and reduction of energy consumption for pumping. Microwave heating is investigated to achieve significant process improvements as compared to conventional heating technology. A lab-scale flow reactor is designed that allows continuous microwave treatment for a maximum oil flow rate of 11 kg/h at 300-400 °C and up to 30 bar pressure. An unique microwave cavity design has been developed to enable short residence time, homogeneous temperature distribution, high energy efficiency, and safe operation at high pressure.

This paper reports on the measurement of sensitivity improvement in passive RFID chips when interrogated by a custom-built RFID reader with improved powering waveforms. The sensitivity of an RFID chip was measured with such reader using a CW and several non-CW signals, and a sensitivity gain of more than 3dB relative to the CW was obtained for a 9-tone multi-sine signal. Similar gain was verified in field experiments.

In this work, the feasibility of a system for the detection of multi-modal RFID sensing is presented. A reader is designed for detecting multiple resonances of frequency-shifting RFID sensors, each resonance corresponding to a different sensed variable. The reader exploits information of the actual return loss between the tag antenna and the RFID IC, rather than the tag power-on threshold that has been typically used in the prior art, overcoming limitations associated with the power-on threshold function. The estimator for extracting the return loss of a tag wirelessly is derived and experimentally tested with a low-cost software-defined radio platform. The developed platform can serve both the purposes of a tag performance testing reader and a central processing station for next-generation multi-sensor RFID tags.

To minimize energy consumption of state-of-the-art wireless nodes, asynchronous communication transceivers are adopted, which make use of a passive wake-up radio (WUR) to minimize the active time of the energy-hungry main communication radio. This work contributes to the ambitious goal of pushing over the average RF power needed to operate the WUR, thus enabling energy-efficient communication in larger areas. To reach this goal a dual-band rectifier, optimized to be loaded by an ultra-low power comparator, is used as the WUR detector. Its behavior is experimentally tested under several power-optimized excitation formats. By selecting the proper excitation format the base-band comparator operation is enabled starting from average RF-power as low as -64.5 dBm.

Backscatter radio is being increasingly used for identification, sensing, and localization. The increased number of pervasive IoT systems that utilize backscatter radio as a low- power and low-cost communication scheme has led to dense deployments of tags that need to operate under bandwidth constraints. However, typical backscatter radio modulators perform switching “on-off” operation and modulate data with square pulses, which are known to occupy more-than-Nyquist bandwidth. This work derives new techniques and and demonstrates front-ends that control the tag reflection coefficient over time in a continuous manner and allow for the generation of arbitrary backscattered waveforms. The principles presented hereby will enable sophisticated tags to perform more complex modulation schemes, while maintaining the RF front-end complexity to low levels.

This work introduces an inductive wireless power transfer (IWPT) and backscattering communication to an extremely small CMOS RFID tag with a size of 200 um by 200 um. This is the smallest RFID tag to date, with the passive area taken into account. DC power of 0.1 mW can be generated on-chip with 21 dBm source power at 2 GHz. An amplitude-shift keying (ASK) back-scattering communication link is demonstrated. The on-chip matching varactor is switched to maximize the distance between the two reflection (backscattering) coefficients. A directional coupler is used to suppress the Tx-to-Rx leakage and to extract the backward scattering wave. An 8-bit, 10-GS/s ADC can demodulate (with >15 dB SNR) the 625kb/s signal.

In conventional passive radio frequency identification (RFID) systems, downlink (reader to tag) and uplink (tag to reader) overlap on the same carrier frequency, which leads to severe self-jamming and reader collision problems. To resolve these issues, nonlinearity in passive RFID tags can be exploited to generate second or higher order harmonics for uplink data communication. The design of harmonic tag that allows efficient energy harvesting and harmonic generation at the same time is critical. We present Harmonic-WISP, the first harmonic RFID system integrated with the open-source wireless identification and sensing platform (WISP). Harmonic-WISP adopts a new routing strategy to ensure full power utilization in both energy harvesting and harmonic generation modes. The new platform can fundamentally eliminate self-jamming issues and can greatly reduce reader-to-reader interference. By integrating with WISP, the proposed platform can further allow flexible implementation and evaluation of efficient multiplexing and security protocols.

In this paper, a miniaturized UHF RFID tag is developed for industrial harsh environment applications like oil and gas industries. The tag is designed based on an open-ended slot structure and fed by a primary radiator from the middle. Feeding the antenna using coupling mechanism by a primary radiator results to lower fabrication complexity and costs as well as mechanical durability against continuous vibrations, humidity, water and mud. The whole tag is 0.084λ×0.066λ and can be read up to 5 m in the US band and 3 m in the EU band. By utilization of low cost FR4 substrate alongside the magnetically coupled primary radiator the fabrication costs diminishes significantly. An open-ended slot fed from the middle with bent T-shape pattern for the closed-end and meandered pattern for the open-ended side acts as the antenna and matching circuit together. The measurement results prove the functionality of the designed tag.

Today AESA antenna is becoming more popular and lowering cost of key component like TR module is crucial to strength that trend, In this paper, a design of a low cost high power X band GaN module is described. In this module, all devices including HPA are surface mounted on resin board, and highly enforced heat dissipation design inside resin are adapted. More over unique anti-radiation property with wholly adapted EM shield design devices, enabling coverless module is described. Prototype transmit module exhibits 13.3W output power with 30.8% efficiency at X band. Operational Isolation between channels is 29dB with coverless configuration. It weighs only 8.5g per channel, and it’s manufacturing cost is estimated to be 40% of our convention GaAs module.

Quilt Packaging (QP) is a direct chip-to-chip edge-interconnect technology that offers extremely low interconnect loss and can be implemented on a variety of substrates. We report here the experimental demonstration of heterogeneous integration between Si and GaAs substrates. Ultrawide-bandwidth Quilt Packaging coplanar waveguide interconnects between Si and GaAs chips are presented along with preliminary thermal shock data. Fabricated structures on ~100 µm thick Si and GaAs chips exhibited chip-to-chip insertion losses below 0.5 dB up to 110 GHz, and below 1 dB up to 220 GHz from on-chip S-parameter measurements. Despite the coefficient of thermal expansion mismatch between Si and GaAs, the interconnects also exhibited no adverse effects from thermal shock testing through 1250 cycles.

In this paper, a packaged F-band transmitter in CMOS 65 nm technology is presented. The integrated circuit is based is based on a x9 active multiplying chain from Ku-band to F-band. The circuit was packaged and connectorized demonstrating the possibility of using wire-bonds around 130 GHz with low insertion loss. The microstrip-to-waveguide transition developed introduces insertion loss below 1 dB from 85 to 145 GHz. On-chip probing of the circuit showed a maximum output power of +8 dBm at 124 GHz with a 3 dB bandwidth of 9.8 % (117-129 GHz). The packaged circuit showed a maximum output power of +6 dBm at 128 GHz resulting in a package RF path insertion loss of 2 dB in average through the circuit -3 dB frequency bandwidth (117-133 GHz).

This paper reports on a planar transition from 1 mm coax to the fundamental mode of a polystyrene rectangular dielectric waveguide (DWG), covering frequencies from 50 GHz to 85 GHz. Two back-to-back transitions connected by a 12 cm piece of waveguide with tapered points were measured, demonstrating an insertion loss between the microstrip line and the dielectric waveguide of about 2 dB, which agrees well with simulated values. The structure consists of a 1 mm coaxial board edge connector feeding a microstrip line on a 4 mil thick liquid crystal polymer (LCP) substrate, followed by a vialess transition from microstrip to slotline patterned on the other side of the substrate. The slotline then tapers out and feeds a tapered DWG that is connected to the LCP board by inserting it into a slit along the center of the waveguide.

An alternative global interconnects solution with minimal signal distortion and propagation loss is explored and reported in this work. This interconnect scheme is made possible thanks to the use of a mode-selective transmission line (MSTL), which supports a fundamental TEM mode in lower frequency range covering DC while it is automatically reconfigured to support the fundamental TE10 mode at higher frequency. An MSTL is designed, fabricated, and characterized providing low-attenuation and dispersion-free picosecond pulse propagation with an excellent output signal-to-noise ratio. This technology allows for a jitter-free signal transmission with data-rates greater than 200 Gb/s through just one printed circuit board.

An ultra-wideband filter is designed for common mode noise (CMN) suppression in high-speed differential signaling. It is realized by etching Ф-shaped pattern on the ground plane beneath the center of differential lines. The equivalent circuit model and surface current distribution are given to explain the working principle of the filter. A test sample is designed and fabricated with standard PCB technology. The measured results show that the fractional bandwidth of the presented CMN filter is 106% with a noise suppression level of 20 dB, while good transmission characteristic is maintained for the differential signals.

We demonstrate the detection of physiological-range glucose in a multicomponent aqueous solution through multivariate analysis of broadband dielectric spectra from 500 MHz to 50 GHz. To enhance the selectivity to glucose, we applied spectral preprocessing on dielectric spectra to extract the feature values of glucose and bovine serum albumin (BSA). Using the regression models derived from different concentrations of glucose and BSA, the analysis was carried out on the solutions with the physiological range of both components. The prediction error of glucose concentration was estimated at less than 73 mg/dL even in various concentrations of BSA. This technique is easily implemented with a microwave blood glucose sensor or in other biomedical applications that essentially require multicomponent analysis.

This paper presents a complex permittivity sensor, integrated in 40-nm CMOS, for microwave dielectric spectroscopy. It utilizes a single-ended patch as a near-field sensing element, embedded in a double-balanced, fully-differential impedance bridge. A low-IF, multi-harmonic down-conversion scheme is employed to extend the characterization frequency range and increase the measurement speed. The implemented architecture is compact, accurate and fast, thus suitable for the realization of future real-time, microwave-based, 2-D dielectric imagers. Measurements on liquids show an rms error of

Using a coplanar waveguide with a series gap in conjunction with dielectrophoresis trapping, consecutive S- parameter measurements between 0.5 and 20 GHz were quickly performed with and without a Jurkat cell trapped to compensate for a relatively noisy and drifting background. Based on sixteen measurements repeated on eight live cells and eight dead cells, differences in both return and insertion losses show two distinct distributions indicating either return loss or insertion loss alone can be used to distinguish a live cell from a dead one. Further, since the frequency dependence is generally linear or absent, discrete-frequency measurement (as opposed to sweep-frequency measurement) of return or insertion loss may suffice. If proven statistically by a much larger number of cells, this should greatly speed up the measurement to facilitate its eventual use in the field.

A novel microfluidic biosensing platform based on Bipolar-Complementary Oxide Semiconductor (BiCMOS) technology is presented. The device is based on a quadruple electrode system and a microfluidic channel that are directly integrated into the back-end-of-line of the BiCMOS stack. For proof of concept repeatable electrical trapping of single SW620 (colon cancer) cells in the quadruple electrode system is initially demonstrated. Additionally, for the first time a microwave intermodulation technique is used for high sesnitivity dielectric spectroscopy, which could pave the way to label-free monitoring of intracellular processes and manipulation such as electroporation.

We describe a microfluidic dielectrophoresis (DEP) cytometer that is able to measure the dielectric properties of single biological cells while in flow over the 100 kHz - 400 MHz frequency range. The device provides both the sign and magnitude of the Clausius-Mossotti factor over the entire beta-dispersion region. A microwave interferometer is used to measure the DEP induced translation of individual cells as they flow over a multi-electrode sensing array. The DEP response of polystyrene microspheres is used to verify and calibrate the device. The spectral response of Chinese hamster ovary cells (CHO) is measured and the corresponding cross-over frequencies are determined.

A channel-selective super regenerative receiver (SRR) system is proposed with improved channel selectivity. The proposed SRR system operates only at a valid incoming signal due to the RF spectrum sensing functionality. To overcome the rough channel selectivity of the SRR, a systemic methodology is proposed for controlling quenching signal waveforms and duty-cycles. From the experimental evaluations, the proposed system presented excellent channel selection capability of the 3.5-MHz channel bandwidth. The proposed architecture can allocate at least three times the number of channels for cognitive IoT sensor networks as that of previous ones.

In a time-varying transmission line (TVTL), the two frequencies, the original RF and the up-converted RF, are cross-coupled through a single-tone carrier. Such property can be used for a frequency-tunable high-gain narrowband amplifier through the creation of the sharp resonance at the up-converted frequency. In this work, the concept of the frequency-tunable notch amplifier based on the TVTL is validated and demonstrated with analysis and experiments. We propose to form a feedback loop of a TVTL in one of its practical implementations called Distributedly Modulated Capacitors (DMC). The narrowband gain of the notch amplifier can be tuned over a wide frequency range by just tuning the carrier frequency that modulates the TVTL. An experiment prototype on a Rogers board demonstrated larger than 17 dB gain with a less than 10 MHz bandwidth at a center frequency tunable from 1.48 to 1.65 GHz.

This paper presents a diversity integrated circuit (IC) for digital satellite radio (SDARS) at 2.3GHz. The IC contains an RF circuit which enables fast adaptive processing of up to three antenna signals for maximum ratio combining in a fast fading scenario. The RF front-end of the diversity system is integrated using 150 nm CMOS technology. The phase of each of the three input paths can be adjusted in quantized steps of 45° from 0° to 360°. If the input signal of one path suffers from fading, a single path can be completely turned off for reducing the power consumption. The diversity IC is evaluated by means of laboratory measurements as well as by tests where antenna signals of real fading scenarios are processed using the presented IC. The results show a typical improvement in radio reception of more than a factor of 4 compared to a conventional reception system.

The Centralized-Radio Access Networks (C-RAN) are one of the current trends for the next generation mobile standards. The main concept of C-RAN is the separation of the baseband processing and management tasks from the radio access units. This paper presents an all-digital, simple and flexible RF uplink section for a C-RAN Remote Radio Head (RRH). The implemented system presents an analog input bandwidth of about 3GHz, being capable to receive any signal up to 5MHz symbol rate while maintaining the current LTE Error Vector Magnitude (EVM) requirements.

Digitization of the TV UHF frequencies has resulted in sparsely occupied TV bands paving way for opportunistic access technologies to be a solution for the impending spectrum demand. Though the researches in digital signal processing for spectrum sensing is showing maturity, the concerns in RF front-ends still needs to be addressed. The document ETSI 301 598 is the latest focusing the technical requirements for the TV white space(TVWS) devices but the pre-requisites for a compliant design is still lacking. This paper serves to integrate the system design aspects of a TVWS device with that of an existing cognitive radio~(CR) enabled front-end to ensure compliance with the ETSI requirements. The complete metrics for a transmit front-end is derived with an focus on a WLAN/LTE secondary user. Step by step it is shown that highIF is the optimized solution for the TVWS cognitive radio with the measurements ensuring the compliance

One of the major drawbacks of chipless ultrawideband (UWB) radiofrequency identification (RFID) systems is the polarization dependence. Most proposed tags have to be specifically oriented with the reader. This paper proposes a bistatic reading system which can rotate both the reader's emitting and receiving polarizations, by using two dual-access dualpolarization UWB antennas. The principle consists of electrically rotating the interrogating signal in transmission, while exploiting the rotation matrix in reception. By being able to rotate both polarizations, it is shown that cross-polarization chipless tags can be read independently of their orientation.

This paper presents the design of a novel chipless harmonic RFID sensor in paper substrate based on a variable attenuator implemented as a resistive network, which drives a single Schottky diode frequency doubler, and a system of nested tapered annular slot antennas. The passive tag is interrogated by a signal at f0 = 1.2 GHz and the signal transmitted back to the reader is converted to 2f0 = 2.4 GHz in order for the system to be immune to clutter returns. The sensor information is encoded in the amplitude of the re-transmitted signal and a dynamic range around 20 dB is experimentally demonstrated.

This paper proposes the first-of-its-kind microfluidics-based encodable and flexible chipless RFID sensor. The prototype, including the microfluidic channels and passive RFID resonators, is manufactured cost-efficiently with sole reliance on multilayer inkjet-printing for the first time. Three microfluidics-based reconfigurable spiral resonators are used to obtain tunable “code” frequencies and encode the RFID with less than 0.5 uL of water per bit. The embedded microfluidics also facilitate sensing of various fluids (e.g. identifying different water-glycerol mixtures). The proposed chipless RFID module maintains a stable performance during bending and can be bent for radii down to at least 12 mm. The proposed encodable chipless RFID module can be used in various application spaces including healthcare monitoring, food quality sensing and liquid leakage detection.

In this effort, the authors improve upon most of the limitations of state-of-the-art chipless sensing technologies, by introducing a novel, and demonstrably robust, platform and reading scheme for long-range, wireless sensing. This platform was built upon a fully-inkjet printed and flexible 30 GHz square patch antenna Van-Atta reflect-array, which provides high RCS over a broad range of interrogation angles, with only a 10 dB decrease in RCS at plus or minus 70 degrees from boresight. Furthermore, the signal reflected by the structure is cross-polarized with respect to that of the impinging wave, providing high polarimetric detectability. For this first application, the device was fully inkjet-printed on a polyimide (Kapton) substrate, whose humidity-dependent permittivity was taken advantage of, associated with an appropriate high performance signal processing scheme, in order to provide the first long-range capable, fully-printed chipless flexible sensor to date.

This paper presents a novel technique for the detection and remote reading of passive temperature sensors. This technique is based on a 3D beam scanning performed by a FMCW radar for measuring the echo level of sensors distributed in a scene. The carrier frequency is 24GHz and two frequency modulation bandwidths are investigated (2 GHz and ISM 250 MHz). The fluctuation of the measured echo level is analyzed by using appropriate estimators and the derived temperature variation is displayed by using a convenient three dimensional representation of isosurfaces.

This paper presents an 8-element 2–16 GHz phased array receiver chip in SiGe BiCMOS with reconfigurable number of beams. An 8-input single-output, or a 4-input dual-output, or a 2-input 4-output beams can be synthesized in this chip. Additionally, two digital beamforming channels can also be used in this chip. The measured 2-input 4-output beam mode results in a gain of 10-11.5 dB at 2-16 GHz with excellent gain flatness. The measured noise figure and input referred P1dB is 11.5-12 dB and ~ -15±1 dBm respectively, at 2-14 GHz. The wideband channel has a 5+3 bit phase shifter control and a 3-bit VGA ensuring a 5-bit phase response with 8 dB gain control over the entire band. The chip consumes 265 mW/channel from a 2.5 V supply.

A built-in-self-test (BIST) system for wide-band phase arrays channels is presented. The BIST is implemented using an on-chip I/Q receiver with an integrated ring-oscillator that provides both the channel test signal and the mixer local oscillator (LO). The BIST achieves wide-band accuracy for relative phase and gain measurements at 2-15 GHz with a onetime self-correction algorithm with 8 LO phases. The BIST measurements agree well with the VNA S-parameter data over a wide frequency range. To our knowledge, this is the first implementation of high accuracy wide-band BIST system for phased-array channels.

This paper presents a novel two-dimensional (2-D) frequency scanning antenna array that can exhibit a full-hemisphere coverage of radiation beams. The proposed 2-D frequency scanning antenna array utilizes transmission-line based microwave metamaterials (MTMs) to realize both leaky wave antennas and antenna array feed networks. By engineering the dispersion of both metamaterial leaky wave antennas and metamaterial feed networks, the proposed passive 2-D MTM antenna array is able to perform one-to-one frequency-space mapping and beamforming over the entire full-hemisphere without using any phase shifters or mixers.

Bi-directional active and passive meandered circularly polarized (CP) composite right/left-handed (CRLH) inspired substrate integrated waveguide (SIW) based leaky-wave antennas (LWAs) are presented. By meandering the microstrip line, the dimension of the proposed five-cell antenna along the scanning plane is reduced by 33.5% compared to the original CP CRLH LWA based on SIW. Furthermore, incorporating the bi-directional amplifiers, the current distribution of the antenna is manipulated to control the radiation characteristics. The proposed active meandered CP CRLH LWA supports both transmitting and receiving operation while delivering enhanced spatial resolution.

A series feed network concept based on a distributed CRLH stripline and couplers is proposed for frequency scanning phase array applications. The characteristics of such a network, which includes a smaller footprint, are discussed and compared to the traditional transmission line series feed network. Design details of an implementation centered around 6GHz are provided, along with measurements results of the standalone network and as a feed for a 4 element antenna array, for validation of the core idea.

This paper presents a Doppler radar system for real-time vital sign monitoring. To reduce the random body movement effect, this system involves two self-injection-locked (SIL) radars that are mutually injection locked to each other using a branch-line coupler and a circulator array. Moreover, the two SIL radars use different gain antennas. As a result, over 97 percent of the body movement is canceled so as to render the vital sign signals liable to appear in real time.

In this paper, high-resolution ultra-high Q double resonant sensor is developed to eliminate humidity and moisture effect in microwave chemical sensing in uncontrolled environment. Double uncoupled split-ring resonators with close resonant frequencies are assisted with active circuitry to increase their quality factor from 51 and 54 up to 150k and 210k at 1.365 GHz and 1.6 GHz, respectively. The purpose of the second resonator is set to calibrate the erroneous effect of ambient humidity and sand moisture in measurement. Based on the proposed technique, root of mean-square-error of processed results of measuring water in humid air was significantly reduced from 169k down to 27k. Material detection with wet-sand surrounding was verified successfully and the materials impacts are completely distinguished from that of the wet sand.

Two different novel SAW type pressure sensing structures were manufactured using micromachining and nanolihographic processes: SAW supported on a GaN/Si (1.2µm/10µm) membrane for the first type structure and SAW supported on a 1.2 µm thin GaN membrane for the second type. The two resonance peaks observed for both structures were identified, using wave shape simulations, as Rayleigh mode and, symmetric Lamb mode respectively. The resonance frequency shift vs. pressure (measured in the 1-5 Bar range), as well as the pressure sensitivity and its sign have been analyzed for both structures and both peaks. High absolute values of the sensitivity (in the range 346…2680 KHz/Bar) and of the pressure coefficient of frequency (in the range 66…278 ppm/Bar) have been obtained. It was demonstrated that the second type structures and the Lamb mode are more pressure sensitive.

Sensing the dielectric constants real part (Ɛ’) and imaginary part (Ɛ’’) of a material under test (MUT) enhances the capability to differentiate between different materials. In this paper a low power dielectric sensor with two DC outputs, based on a K-band sensing structure, is presented. The full solution is implemented in a standard 0.13 μm SiGe:C BiCMOS technology. Different concentrations of ethanol and methanol solutions were used to demonstrate the functionality of the proposed approach. The sensor showed a responsivity of 10 mV/ Ɛ’ and 100 mV/ Ɛ’’. The sensor can detect a variation of 0.15 of Ɛ’ and 0.002 of Ɛ’’ based on phase noise measurements and simulations. With the DC outputs and a total power consumption of 74 mW the proposed sensor architecture is well suited for lab-on-chip systems.

The measurement of angular displacement and velocity is necessary in many space applications. This paper reports a novel microwave rotary sensor that is contactless, low cost, and robust in space environments. The stator part is a coplanar waveguide loaded with a pair of split ring resonators, whereas the rotor is a periodic circular array of split ring resonators. The stator and the rotor are arranged face-to-face, and the splits of the stator and rotor rings are on opposite sides, giving rise to a broadside-coupled split ring resonator (BC-SRR). Its resonance frequency depends on the relative position between the stator and rotor rings, which determines their coupling. The key point is the fact that the period can be made as small as the printing technology allows for, making quasi-instantaneous measurements possible. By feeding with a fixed harmonic signal at the BC-SRR resonance frequency, the angular velocity can be accurately determined.

This paper presents the preliminary evaluation of a wearable 1-dimensional frequency multiplexed sensor array using microstrip-line-excited complementary split-ring resonators (CSRRs) module for detecting the location of the wrist. The sensor array was fabricated on a cylindrical structure, and a scheme was devised by which to measure relative changes in the location of the wrist within a wearable devise. Unlike previous devices that record changes in the resonant frequency as well as the depth of the transmission notch, the proposed method requires only the magnitude of the transmission coefficient (dB) at a specified frequency, thereby avoiding the need to track shifts in the resonance frequency. Experiment results demonstrate the performance of the sensor in detecting relative changes in distance (1.16 dB/mm) from 0 - 20mm.

This paper reports a design methodology for a tri-coil system that can wirelessly transfer power from a macro-scale probe to a chipscale apparatus over a long distance and with a high efficacy. Such systems can be employed for enabling the wireless charging and communication between implanted body sensors and smart phones as well as between hardware roots of trust and their interrogation probes. A design example has been offered and subsequently validated by an experimental testbed consisting of micro-fabricated coils on both sides of a Silicon substrate. As predicted by the analytical models, the measured power transfer efficacy (PTEF) of the designed system is as high as -27 dB at the resonance, confirming an orders-of-magnitude higher PTEF than that of prior WPT systems over a distance greater than 5 times the coil diameter.

In this paper we propose a geometry design solution to minimize performance variation of a wireless power transfer system “on the move”. A sequence of switchable couples of coils, connected in series or in parallel, is adopted at the fixed transmitting link side; the geometry of the moving receiver is optimized to keep the coupling factor, and thus the power transfer, constant during the movement. Starting from the analytical formulation of the link coupling factor, selected geometry parameters of the receiver are optimized by means of full-wave analysis. In this way a constant power transfer is demonstrated by the optimized geometry. The design and experimental verification are carried out for a geometry suitable for medium power transfer (tens of Watts) at 6.78 MHz, but the method is formulated in such a way that the system can be scaled up and down to accomplish different application needs.

In this paper, a novel real-time active matching circuit design process based on preliminary measurements and a hybridization of a genetic algorithm and a data mining method is discussed. As a result, our proposed matching circuit can potentially have higher dc output power at 92.0 % and 69.6 % of potential load combinations with a maximum matching performance improvement of 21.4 % and 37.6 % compared to conventional matching methods using dc-dc converter and a fixed passive matching circuit, respectively. After the reduction of matching circuit variable choices utilizing the clustering method, it is possible to achieve a satisfactory matching in practically very short times in the order of 1 ms.

In this paper, class-E power amplifiers (PAs) and rectifiers, operating at UHF band, are properly integrated in efficient AC-to-RF and RF-to-AC converters for their use in 50/60 Hz wireless power transmission (WPT). Slightly modifying a center-tap full-wave rectifier, it is proved that a 915 MHz frequency carrier may be high-level amplitude modulated by each of the semi-cycles of the utility waveform. Assuming those components are transmitted by means of orthogonal antenna polarizations, the high-fidelity recovery of both semi-sinusoids in the remote position is also demonstrated, to be stepped-up and combined at the D port of an additional center-tap transformer. GaN HEMT packaged devices were selected for the designed PAs, while Schottky diodes for the rectifiers, resulting in average efficiency figures of 83.3% and 75.4%, respectively.

This paper presents the design and implementation of a high efficiency and high power wideband GaN RF synchronous rectifier. The rectifier circuit is constructed from a wideband amplifier using the time reversal duality principle. Measurement results are presented for both the amplifier and rectifier. Under identical source power conditions the amplifier has a power efficiency of 79.2% and the rectifier has a power efficiency of 80.1% with a DC power about 8 W. Power efficiency is also measured over a broad bandwidth and remains above 60% over a frequency range from 600 MHz to 1150 MHz.

Ambient RF energy especially in urban settings is suitable for harvesting scenarios provided one is able to collect signals from a large number of frequency bands and consequently spanning a large aggregate bandwidth. A broadband rectifier is designed capable of harvesting RF energy in the 400 MHz – 1 GHz range, which includes the analog and digital TV bands and the UHF ISM 900 MHz band. In order to obtain a sufficiently large rectifier bandwidth, a matching network based on a non-uniform transmission line is considered. A charge pump rectifier is used and the number of diodes in the circuit is optimized in order to facilitate impedance matching based on the Bode-Fano limit. The rectifier has a measured efficiency above 5% from 470 MHz to 990 MHz at -20 dBm input power, which increases above 60% at 10 dBm input power over a band from 470 MHz to 860 MHz.

Combined microwave heating and radiometry provides a promising means of the noninvasive measurement of blood perfusion. In this paper, a microwave system, along with a perfusion mimicking setup, for perfusion/flow measurement is described. This paper also presents for the first time i) considerations for achieving high sensitivity of temperature response versus flow, ii) radiometer measurement of temperature decay at the presence of flow, iii) proper choice of the perfusion phantom to mimic the tissue permittivity, and iv) insights on the proper choice of heating and radiometry frequencies from the near-field antenna beam and bioheat transfer considerations.

Chronic wounds affect millions of patients around the world and their treatment is challenging as the early signs indicating their development are subtle. In this article, we present an unprecedented low cost continuous wireless monitoring system, realized through inkjet printing on a standard bandage, which can send early warnings for the parameters like irregular bleeding, variations in pH levels and external pressure at wound site. The bandage can detect 10 μl of blood and 20 mmHg of external pressure and can communicate upto a distance of 60 m when worn on the body. In addition, this smart bandage concept can provide long term wound progression data to the health care providers. The smart bandage comprises a disposable part which has the inkjet printed sensors and a reusable part constituting the wireless electronics. This work is an important step towards futuristic wearable sensors for remote health care applications

To utilize the benefits of parallel transmission in MRI using a transmit coil array, mutual coupling between elements should be minimized. In addition to mutual reactance, mutual resistance also contributes to coupling especially at higher frequencies and in presence of high dielectric constant pads. This paper describes a three-channel transmit array where the elements are decoupled using capacitive bridges in presence of dielectric pads. Both mutual resistance and reactance are minimized and their effects on the transmit performance are investigated.

Medical implants often prevent patients having Magnetic Resonance Imaging (MRI) scans because the leads behave as antennas with respect to the RF excitation and cause hazardous heating in neural tissue. This manuscript describes an approach that virtually eliminates the risk of RF heating by means of easily-incorporated, mutually-coupled filars. The resulting leads need be neither physically larger nor significantly more costly than existing designs. Combined with thin insulation and surface roughening techniques, this manuscript represents the first complete release of recently-patented technologies. Both simulations and measurements at 128MHz are presented to confirm performance in 3-Tesla MRI machines.

This paper presents a novel coplanar waveguide transmission line microwave heater, realized on a high-resistivity silicon wafer with etched microfluidic channels that is bonded to a glass wafer. The heater is a 50 Ohm line with variable attenuation constant along the length of the line. This design results in a uniform energy dissipation in water filled channels, and obviates the need for additional matching structures. The heater was measured around the 25.5GHz design frequency and the obtained S21 data agree to within 0.04 dB with COMSOL Multiphysics simulations for liquid temperatures from 20 to 50 ºC.

Introducing reconfigurable spatial filtering prior to ADC in digital beamforming (DBF) receiver (RX) arrays can improve the RX tolerance for in-band out-of-beam jammers. Such spatial filtering can be achieved using a Butler matrix that provides multi-beam outputs. In this paper, an integrated 4x4 reconfigurable X-Band Butler matrix is designed in SOI CMOS to provide multi-beam output with frequency tunability. The hybrid couplers that constitute the Butler matrix can also be configured to have

This paper presents an ultra-broadband ultra-compact Butler Matrix design scheme. The design employs stacked transformer based couplers and lumped LC π-network phase shifters for substantial size reduction. As a proof-of-concept design, a 4×4 Butler Matrix is implemented in a standard 130nm bulk CMOS process at a center frequency of 2.0 GHz. Compared with reported fully integrated 2.0 GHz 4×4 Butler Matrix designs in CMOS, the proposed design achieves the lowest insertion loss of 1.10dB, the smallest amplitude mismatch of 0.3 dB, the largest fractional bandwidth of 34.6%, and the smallest chip core area of 0.635×1.122 mm2. Based on the measured S-parameters, the four concurrent electrical array patterns of the Butler Matrix achieve array peak-to-null ratio (PNR) of 29.5 dB at 2.0 GHz and of better than 15.0 dB between 1.55 GHz and 2.50 GHz.

This paper presents a reconfigurable focal plane array (FPA) for lens or reflector based antenna systems in the 24 GHz ISM band. The FPA consists of five equal uniformly-spaced antenna elements with switchable polarization, fabricated on a four layer substrate using conventional low-cost PCB technology. For compactness and increased bandwidth, the design is based on aperture-coupled patch radiators on top of the substrate, each embedded in a cavity in order to reduce mutual coupling. Feeding is done by means of two orthogonal H-shaped slots which are excited by microstrip transmission lines etched on the bottom layer. A discrete pin-diode single pole, double throw (SPDT) switch directly below the patch allows for polarization control and facilitates a compact element size of 10 mm x 10 mm including the cavity walls. Another discrete pin-diode SP5T switch allows the selection of one of the five FPA elements at a time.

A new topology of a reflection amplifier is proposed and demonstrated using CMOS FD-SOI 28 nm process for high gain reflectarray antenna applications. The design is based on two sets of cross coupled pairs which are coupled inductively. An internal oscillations-block was implemented in order to improve the stability of the amplifier. Variable stable gain of 5-25 dB at the bandwidth of 106-127 GHz was achieved, with output power of up to 0 dBm (measurement limited). The total power consumption was 6-20 mW, depends on the exact bias configuration. The reflection amplifier results with a 3-dB bandwidth of up to 18%. The design consumes a core area of only 90x80 m2 and allows the implementation of a high efficiency active reflectarray antennas

a novel dual-band co-aperture antenna array with high bandwidth is presented. The proposed frequency bands of interest are E-band and LMDS which can work simultaneously in a dual-band mm-wave radio to achieve high throughput. The distribution network is based on the combination of Substrate-Integrated-Waveguide (SIW) and stripline technologies. The SIW distribution network feeds slot apertures with a special offset from the center axis of the waveguides, while the stripline lines excite U-shaped patch antennas by vertical vias. A 4×4 dual-band E-band/LMDS array prototype is presented to validate the concept. The dual-band antenna array is approximately 12mm×12mm in size realized on a Rogers 4350 substrate. Measured results versus simulations have been presented and discussed. This dual-band technique can be a great candidate for the multi-Giga-bit/s (Gbps) cellular applications for 5G communication and is compatible with low cost multilayer technologies.

Full-duplex radios realize simultaneous bi-directional communications in the same frequency band. However, one of the bottlenecks is how to mediate the self-interference (SI) between the transmitter (Tx) and the receiver (Rx). In this paper, a novel passive microwave device called Coupled-resonator Decoupling Network (CRDN) is proposed. A prototype CRDN is built and tested for proof-of-concept, where the four-port device consists of two inter-coupled lines of coupled resonators. The SI is suppressed from -17 dB to below -41 dB within a frequency range of 50 MHz. This performance is superior to other RF front end SI cancellation schemes and demonstrates the potential applications of such device in a full-duplex wireless communication system.

This paper presents a millimeter wave mobile station radio frequency unit (MS RFU) operating at 28GHz with two receive (Rx) and two transmit (Tx) chains for MIMO or diversity where each chain utilizes beam steering to enhance signal to noise ratio (SNR). Each phased array employs 4 substrate integrated waveguide (SIW) antenna elements incorporated within the main printed circuit board (PCB). The RFU supports up to 800MHz signal BW and 64QAM OFDM signal with -27dB EVM.

We present the design and measured results of a fully integrated Ka-Band front end on a 0.15-m GaAs pHEMT process. The integrated front end includes a three stage power amplifier, three stage low noise amplifier, and single pole, double throw switch. The integration of the front end is a crucial step to commercialize mm-Wave technology for 5G mobile communication. In addition to the fully integrated front end module, these three components were fabricated separately for individual characterization and analysis, and those results are presented in this paper.

This paper presents a 60 GHz communication link system and measurements using a 64-element phased array transmitter. The transmit array includes high-efficiency on-wafer antennas, 3-bits amplitude and 5-bits phase control on each element, and a measured EIRP of ~38 dBm at 60 GHz and scans to +/- 55° in the E- and H-planes with near-ideal patterns and low sidelobes. The phased-array transmitter is used in a 60 GHz communication link with an external up-conversion mixers and Keysight 802.11ad waveform generator. A standard gain horn with a gain of 21 dB is used as the receiver, coupled to a Keysight high-speed demodulation scope. The communication link achieves a 16-QAM modulation with 3.85 Gbps at 4 m (full 802.11ad channel) and a QPSK modulation with 1.54 GBps over 100 m while scanning to +/-45° in both planes.

Distributedly modulated capacitors (DMC) is a discrete realization of time-varying transmission line (TVTL), which offers broadband nonreciprocity through time modulation of the transmission line property and compensating the circuit loss with the parametric gain [2-4]. The low-noise, broadband behavior of the DMC and its IC compatibility makes it ideal for Simultaneous Transmit and Receiving (STAR) applications. In this paper, a MMIC implementation of the DMC is presented with its performance experimentally verified. Furthermore, a circulator prototype consisting of a pair of DMC MMICs in a balanced architecture is assembled and tested. More than 25 dB TX-to-RX isolation and less than 4 dB RX loss is demonstrated in the experiment over the frequency of 0.7 to 2.5 GHz.

A 2.59GHz self-interference cancellation (SIC) circuit is presented for in-band full-duplex radio. The SIC circuit is based on an analog vector modulator whose output can automatically track the time-varying self-interference signal through an analog LMS algorithm based weight calculation circuit. By adding a variable gain stage after the vector modulator, the total dynamic range is significantly widened so that the SIC can deal with large Tx power variation and/or Tx-to-Rx attenuation. Implemented in 16.4ⅹ11.9 cm2 printed circuit board, the circuit achieves the cancellation ratio of 39.2 dB and 39.4 dB for 5MHz and 10MHz bandwidth 16-QAM signal, respectively. Also, the dynamic range is increased from 22 dB to 40 dB by properly setting the variable gain.

This paper presents an approach improving phaseless Direction-of-Arrival (DoA) estimation accuracy for indoor environments. The positioning system’s anchor is equipped with a dual-band transceiver and a switched beam antenna, operating in circular polarization. Considering the weak correlation of the multi-path at incommensurate frequencies, the data fusion collected at both 2.45GHz and 5.7GHz is expected improve the estimation performance. The experimental validations demonstrate the performance of the proposed approach positioning the node at the distance of 3.5 m inside a 5×4×3 sqm setup, being the latter perturbed with a large and invasive conductive ground aimed at the multi-path generation. Despite a very critical localization result at each single frequency, with a worst case of 90% of the observed domain affected by an error up to 50 deg, the data fusion approach boosts the performance getting the error below 12 deg, demonstrating the effectiveness of the proposed approach.

This paper demonstrates the efficient use of microwave dielectric spectroscopy for single cell irreversible electroporation monitoring. The experimental results point out a high correlation (R2 higher than 0.94) with biological gold standard technique based on flow cytometry whereas microwave approach features several key advantages: marker-less, contact-less and in-liquid cell(s) monitoring. The developed microwave and microfluidic-based biosensor reveals an increase in the capacitance and the conductance of single cells under investigation subjected to irreversible electroporation reflecting an increase in cell damage which is in great correlation with results routinely obtained in biology. More interestingly, the cell’s damage post electroporation have been experimentally quantified overtime, which made the microwave dielectric spectroscopy a technique of interest for cell’s electroporation researches.

Electroporation of Jurkat human lymphoma cells were investigated under 10-MHz continuous waves and benchmarked against that at 100 kHz. Both cell poration and cell death were monitored in real time by fluorescence microscopy and found to occur at approximately three times higher voltages at 10 MHz than that at 100 kHz. This difference in voltage could not be completely accounted for by order-of-magnitude estimate of cytoplasm resistance and membrane capacitance. Better modeling and simulation of the cell structure and property are required to accurately predict the frequency dependence of electroporation.

Background microwaves are ubiquitous in our modern, urban environment. The thermal effects of these electromagnetic fields on biological matter have been well-researched. However, possible non-thermal effects remain a controversial subject. Our work utilizes the bioluminescent marine organism, Vibrio fischeri, as a biosensor to probe the effects of low power, pulsed magnetic and electric microwave fields. The ultimate aim of this project is to microscopically image these biological effects in real-time using custom-made luminophores in mammalian cells in order to elucidate the mode of action of microwaves at the molecular level.

This paper presents the first use of Ku band energy at the spot frequency of 14.5GHz for the treatment of a range of dermatological conditions. Initial in-vivo and ex-vivo results are presented, together with histology and data analysis. The outcome from this work indicates that 14.5GHz energy has a strong potential for future use in treating a number of dermatological conditions, where control of depth in the millimetre range and uniformity over the area of the heating profile are important. The initial in-vivo work indicates that it is possible to ablate well-defined areas of collagen followed by good epidermal repair.

Current paper presents the experimental evidence in favor of low-intensity microwave effects implemented by the original approach to irradiation of blood for therapeutic purposes. It applies microwave-assisted autohemotherapy using cylindrical cavity resonator operating at a wavelength of 7.2. mm (f = 41.6 GHz). The details of the applying technique and the developed device have been described. Our preliminary results revealed improving outcomes in patients who received the course of integrated therapy (10 procedures of microwave autohemotherapy) manifesting at both the cellular and organism level.

Harmonics of respiration frequency due to nonlinear Doppler phase demodulation may interfere the identification of heartbeat frequency in vital sign radar's baseband spectrum. The proposed adaptive harmonics comb notch filter is a type of spectrum-based filtering function with no degradation on the heartbeat signal, and no calibration is needed when the detection distance changes. Experimental results show that the proposed filter for removing respiration harmonics can help measuring laboratory rat's heart rate more accurately when the heartbeat movement is weak or overwhelmed by the respiratory movement in the detected spectrum. Furthermore, even when the heart rate is totally overlapped by the respiration rate harmonics, the heart rate can still be extracted.

In this paper, a metamaterial-based scanning leaky-wave antenna is developed, and then applied to the Doppler radar system for the noncontact vital-sign detection. With the benefit of the antenna beam scanning, the radar system can not only sense human subject, but also detect the vital signs within the specific scanning region. The Doppler radar module is designed at 5.8 GHz, and implemented by commercial integrated circuits and coplanar waveguide (CPW) passive components. Two scanning antennas are then connected with the transmitting and receiving ports of the module, respectively. In addition, since the main beam of the developed scanning antenna is controlled by the frequency, one can easily tune the frequency of the radar source from 5.1 to 6.5 GHz to perform the 59 spatial scanning. The measured respiration and heartbeat rates are in good agreement with the results acquired from the medical finger pulse sensor.

This paper presents a portable 24-GHz auditory radar system for non-contact robust speech information sensing. To measure the tiny vibration on human throat induced by vocal cords, a high operating frequency and a pair of 4\multiple4 antenna arrays are utilized to achieve high sensitivity. Experiments under high-level background noise and voice interference are carried out. Compared with the microphone-detected results, the developed radar system can accurately acquire high-resolution time-varying speech information with good noise rejection and directional discrimination.

This paper presents a novel method of using AC coupled quadrature Doppler radar for gesture classification. A barcode is generated based on time-domain zero-crossing characteristics of quadrature components in reflected signals of hand gesture. Each motion is repeated within 60 seconds to create a distinguishable pattern on a barcode plot, which can be used for differentiation of motion types and gesture classification.

A new 9.4/18.8 GHz harmonic radar transponder for the bee searching radar is proposed. The proposed transponder reduces the degradation of the conversion rate from the loss of the bee’s body effect and promotes the antenna gain. It is designed in the way of differential operation with two resonate frequency at 9.4 and 18.8 GHz. It also has a smaller size which can be mounted on bees. The omnidirectional gain in E-plane is above 0 dB and the degradation of the conversion rate from the loss of the bee’s body effect is 3-4 dB. This improvement is helpful to extend the detection range of the bee searching radar.

A active quasi-circulator (QC) with high bandwidth is proposed for monostatic FMCW automotive 77-GHz radar sensors. The QC is build around a commonly used differential LNA. As the layout of the QC is symmetrical in contrast to traditionally active QCs, the system is robust and offers a high bandwidth in respect with transmit to receive signal isolation. A single ended to differential conversion is also provided by the proposed structure without any additional losses, which directly improves the noise figure performance of the receiver. Effects like process variations and antenna mismatch can be compensated by a digitally controlled CMOS based impedance tuner acting as a leakage canceler. The system has been fabricated in a 250-GHz fT BiCMOS technology. Over a 10-GHz bandwidth, the receiver gain is higher than 7 dB. Assuming an isolation of 30 dB, the bandwidth remains 8 GHz.

This paper presents an interference-tolerant radar which can endure multiple signals transmitted from adjacent vehicles for autonomous driving applications. The interference immunity property has been realized by applying a specific code-division multiplexing method, involved with one-coincidence frequency hopping code, to the continuous-wave radar. We have implemented such a radar prototype in 65nm CMOS for operation at 24GHz with 1GHz bandwidth (equivalently with 15cm range resolution). Measurements indicate that the prototype can support up to 22 adjacent vehicles simultaneously by using the optimized Hamming correlation property of the extended hyperbolic congruential code.

In this paper, a novel frequency synchronization scheme between platforms for a bistatic SAR is described. The proposed scheme uses the direct return signal to compensate a time varying Doppler-shift. The synchronization is established by using a PLL technique. And in a PFD of the PLL, the Doppler-shift of a reference signal for the PLL is canceled out by the Doppler-shift of the direct return signal. A detail analysis of the synchronization error for the proposed scheme is presented. Experimental results show that the proposed scheme achieves stable frequency synchronization between the platforms under the time varying Doppler-shift. And theoretical analysis and experimental results indicate that the synchronization error of 3.3×10-12 can be achieved in the assumed condition. This synchronization error is enough to satisfy the requirements for bistatic SARs.

We investigate a phase-coded multiple-input multiple-output (MIMO) radar approach which uses concatenated codes based on Hadamard matrices and almost-perfect autocorrelation sequences (APASs). Due to the structure of concatenated codes, the implementation of the correlators can be realized with a favorable small number of taps compared to the overall sequences length. However, these type of sequence set has also some limitations, which we address in this contribution. Therefore, we point out how to manage these imperfections based on numerical simulations and measurements, which we carried out using a software defined radar (SDR) platform with 16 MIMO channels at 77 GHz.

This paper presents an compact bistatic FMCW radar MMIC at 160 GHz with a mixer-based synthesizer concept. The mixer converts a ramp signal with a stabilized local oscillator (SLO) signal to RF. Using a mixer reduces the frequency multiplier of the ramp signal and hence improves the phase noise at RF. Due to the fixed SLO frequency for the up-conversion this signal can be assumed having a comparably small phase noise level compared to the ramp input signal so that it does not contribute significantly to the phase noise level at RF. Besides the synthesizer, the MMIC includes a power amplifier with maximum output power of 2 dBm, two integrated antennas, and an IQ-receiver. Radar responses recorded with a bandwidth of 20 GHz show the dynamic range of this sensor and its near range behavior. The MMIC requires a chip area of 1.4 mm×1.0 mm and consumes 285 mW.

We present a solution where one single LO chain is used to feed a homodyne FMCW radar transceiver. An InGaAs pHEMT active frequency multiplier MMIC (x8) and a Schottky diode frequency doubler make up the LO chain. The novel Schottky diode based transceiver operates both as a frequency multiplier (x2) and as a sub-harmonic mixer. The modules operate at a center frequency of 340 GHz with a 30 GHz modulation bandwidth. An output power of 0 dBm, an IF noiselevel of -168 dBm/Hz and a receiver conversion loss of 18 dB is achieved in the band. The form factor of the modules is adapted to build one- or two-dimensional FMCW radar arrays. State of the art system performance is achieved while system complexity, size and cost is significantly reduced.

Two CMOS synchronous rectifiers have been imple- mented using 0.13 μm technology. Together, the two designs can rectify a 2.4 GHz RF input signal over a 40 dB dynamic range from -30 dBm to +10 dBm. The CMOS rectifiers are designed to operate either as class-B or class-C synchronous rectifiers. In one design, a zero-threshold voltage device is shunted by a positive threshold device to provide rectification at very low RF input power levels. At low power, the zero-threshold device operates in the class-B mode, and once the RF input power is large enough, the second device starts to rectify in the class-C mode. A second design operates entirely in the class-C mode and provides good rectification for RF power levels above 0 dBm.

This paper demonstrates a millimeter-wave RF-to-DC converter based on Schottky-barrier diodes in 0.18-um CMOS technology. The Schottky-barrier diode has a cutoff frequency of 400 GHz and a low turn-on voltage of 0.3 V. In the RF-to-DC converter, the difference in turn-on voltage between the Schottky diode and n-well to p-substrate parasitic pn junction prevents the pn junction from turning on with an effect similar to the Schottky diode clamp in Schottky TTL circuits. The input matching has a better than 10 dB return loss from 50 GHz to 100 GHz. The RF-to-DC converter can generate 3.15 V DC voltage at 84 GHz.

This paper presents a battery-less mm-sized wirelessly powered injection-locked oscillator with on-chip antennas in 180nm SOI CMOS. The chip harvests electromagnetic radiation from a continuous-wave source in the X-band using an on-chip antenna. In addition, the chip is equipped with a broadband injection-locking oscillator that locks to the frequency of the input and produces a synchronized signal at the half frequency of the input. The new signal is then radiated back using an on-chip dipole antenna. This architecture resolves the conventional self-interference issue in RFID sensors by separating the received and transmitted frequencies. In addition, the locking mechanism improves the phase-noise of on-chip oscillator to -94dBc/Hz at 100Hz offset.

A fully-integrated rectenna with a chip area of 0.43 mm2 is designed for ISM 915 MHz band for battery-less ultra-low-power body implantable applications. The circuit is implemented in GlobalFoundries 45 nm CMOS SOI technology and is based on a miniaturized slot antenna integrated with a novel full-wave cross-coupled bridge rectifier design that facilitates low turn-on voltage and very low leakage current. When excited by a 0.95 GHz signal through a horn antenna with an effective isotropic radiated power (EIRP) of 36 dBm, the rectenna provides more than 50 μW of DC power and a rectified DC voltage of higher than 1 V at distances below 16 cm. Power harvesting increases to 1.4 mW at distances below 2cm. The device provides 1 V / 50 μW DC power when placed under a 1cm thick chicken breast tissue at distances of up to 4cm, while powered from 36 dBm EIRP transmitting antenna.

In this study, we introduce a triple-band flexible implantable antenna that is tuned by using a ground slot in three specific bands, namely Medical Implanted Communication Service (MICS: 402~405 MHz) for telemetry, the midfield band (lower gigahertz: 1.45~1.6 GHz) for Wireless Power Transfer (WPT), and the Industrial, Scientific and Medical band (ISM: 2.4~2.45 GHz) for power conservation. The telemetry performance of the proposed antenna was simulated and measured by using a porcine heart. To check the feasibility of WPT, a midfield transmitter antenna was introduced. In addition, to reduce the unwanted power leakage due to WPT, a Near Field Plate (NFP) was also used. Finally, power conservation can be realized by triggering the antenna’s ‘sleep mode’ in the ISM band.