A compact three-dimensional four-way vectorial steering module using low-temperature co-fired ceramics multilayer technology, hybrid-integrated with monolithic microwave integrated circuits for flexible satellite payloads operating in the Ka-band downlink frequency range of 17–22 GHz is presented. The module features digitally controllable actuators and hermetic sealing at a compact size of 26 mm × 44.5 mm × 4.4 mm. For feeding the module with a single input signal, a one-stage four-way Wilkinson power divider was designed incorporating buried resistors, fabricated, and measured. The divider exhibits a return loss of > 12 dB at all ports. The isolation of the output ports is > 15 dB, transmission phase difference remains below 4.3 degrees, and the insertion loss is below 1.3 dB. The vectorial microwave parameters of the module can be adjusted by 344 degrees for phase and 15.5 dB for amplitude with 5-bit resolution, at stepsizes of 11.25 degrees and 0.5 dB, respectively.

This paper presents an electrically tunable dielectric line based on a fiber topology. A fiber segment is filled with liquid crystal (LC) for continuously tuning the differential phase between 0°-90° by an applied biasing voltage. This tunable dielectric delay line phase shifter is aimed to be implemented into a RF switch (SPDT), to switch between the calibration loads and the antenna of a radiometer at 100GHz. A subwavelength topology was chosen, where compared to classical dielectric waveguides, air is acting as cladding material, ensuring a low loss propagation comparable to hollow waveguides. The phase shifting section has a total length of 26mm and provides a maximum differential phase shift of more than 107° and 115° at 100GHz for electric and magnetic biasing, respectively. Accompanied with insertion losses between 2.5-3.0dB, the phase shifter shows a figure of merit of 42°/dB for the electric and 44°/dB for the magnetic biasing.

A low loss dielectric rod waveguide design is proposed for use at Ku band. Measured waveguide performance from 10 to 18 GHz is presented and validated using full wave numerical simulations. The proposed design uses a low permittivity cladding to improve performance at the low end of the operating frequency band. Moreover, an improvement of the waveguide isolation due to the cladding is also analyzed. The proposed ABS cladding is also implemented on a dielectric end-fire antenna obtaining an improvement in return loss, gain and half power beamwidth at the low end of the Ku band; the measured peak gain at 12.2 GHz is 14.6 dBi and 9.8 dBi with and without the cladding, respectively, and the 3 dB beamwidth changes from 22 to 61 degrees.

A novel negative-resistance composite right/left-handed (NR-CRLH) leaky-wave antenna (LWA) is presented. The conventional CRLH unit cell is enhanced by a configurablemade reconfigurable using negative resistance circuit. An LWA constituted by the proposed unit cells allows manipulation of the current distributions over the radiating surface of the antenna. Consequently, the radiation pattern, gain, and directivity can be adjusted to the desired values. The fabricated prototype of the proposed NR-CRLH LWA demonstrates enhanced directivity compared to the conventional all passive CRLH LWA. The proposed method provides simple current amplitude control while minimally influencing the desired dispersive/transmission characteristics of the LWA.

Two-dimensional transmission line (TL) grids have been shown to demonstrate interesting behaviors, such as effective negative refractive index and growing of evanescent waves. The analytical treatment of periodic TL-grid structures in the literature predicts a closed bandgap dispersion relation and 2 eigenmodes for a symmetric unperturbed TL-grid unit cell. In this paper, it is shown that unloaded 2D TL-grids inherently exhibit an open bandgap in the dispersion relation and the TL-grid has to be perturbed for successful closing of the bandgap. Furthermore, it is shown that there is a flat (deaf) band in the dispersion relation which is regarded as an additional third eigenmode. Finally, based on this analysis, a 2D single-point fed TL-grid Dirac leaky-wave antenna (DLWA) design is fabricated. Experimental results show true broadside radiation, which is a proper indication of the successful closure of the bandgap in the dispersion relation.

This paper presents a VCO that utilizes the analog capacitive tuning properties of a MEMS varactor for continuous frequency tuning. The MEMS based VCO achieves a tuning range from 3.37 to 3.58 GHz and a superior phase noise performance of -134.5 dBc/Hz at a 500 kHz offset from the carrier. This work shows the potential of MEMS varactors as attractive alternative to standard varactor solutions for frequency tuning of high performance VCOs.

A 1.4-2.1 GHz compact tunable 3-pole bandpass filter with improved stopband rejection using RF-MEMS capaciters and varactor diodes has been demonstrated. The MEMS capacitors are fabricated and fully packaged using a 0.18 um CMOS standard process with integrated high voltage drivers and SPI control logic and with reliability in the billions of cycles. The 1.4 - 2.1 GHz filter results in insertion loss < 2 dB with 1-dB fractional bandwidth (FBW) of 12-13%. The proposed design has highly improved stopband rejection compared to a standard combline filter. The application areas are in modern multi-standard communication systems.

Inductive coupling and matching networks are used to increase the bandwidth of filters realized with aluminum nitride contour-mode-resonators. Filter bandwidth has been doubled using a combination of a wafer-level-packaged resonator chip and a high-Q integrated inductor chip. The three-pole filters have a center frequency near 500 MHz, an area of 9 mm x 9 mm, insertion loss of < 5 dB for a bandwidth of 0.4%, and a resonator unloaded Q of 1600. This work demonstrates the ability for co-integration of microresonators and inductors to broaden filter bandwidths beyond the normal limit imposed by the material coupling coefficient, and the ability to perform microresonator filter tuning with external passive elements.

This paper reports the first octave-tunable K-band MEMS continuously tunable band-pass cavity filter with enhanced frequency stability by incorporating a creep-resistive Au-V micro-corrugated diaphragm (MCD) tuner. All filter components are fabricated with silicon micromachining and techniques. The filter’s measured tuning range is from 20 to 40 GHz with fractional bandwidth ranging from 1.9% to 4.7%. The filter’s measured loss varies from 3.09 to 1.07 dB including its connectors. The Au-V tuner results in significantly improved frequency stability with a 7× slower drift rate (phase II creep) compared to previously reported stare-of-art MEMS tunable filters based on Au-based MCD tuners. However, this comes at a cost of an additional 0.15-0.9 dB loss due to the higher resistivity of AuV. This large increase in frequency stability with a low-to-moderate increase in loss is a desirable trade-off for most applications.

This paper presents the design, the realization and the measurement of a thin-film packaged RF-MEMS switched capacitors. Packaging is included in microelectronics fabrication process, with Silicon Nitride thin film. The capacitors are actuated by deflecting thin gold metal membranes towards the package dielectric, increasing the capacitance by a factor 2.3. The device size, including its packaging, is 50 × 40μm² . Pull-in and release voltages have less than 5V variation between 20°C and 85°C. The device has been tested with 20 dBm applied power and shows no sensitivity to incident power.

This paper reports the design and development of aluminum nitride (AlN) piezoelectric RF resonant voltage amplifiers for Internet of Things (IoT) applications. These devices can provide passive and highly frequency selective voltage gain to RF backends with a capacitive input to drastically enhance sensitivity and reduce power consumption of the transceiver. Both analytical and finite element models (FEM) have been utilized to identify the optimal designs. Consequently, an AlN voltage amplifier with an open circuit gain of 7.27 and a fractional bandwidth (FBW) of 0.11 % has been demonstrated. This work provides a material-agnostic framework for analytically optimizing piezoelectric voltage amplifiers.

Improvements to the GeTe inline phase-change switch (IPCS) technology have resulted in a 10x increase in the figure-of-merit (FOM) for radio-frequency (RF) switches. An ON-state resistance of 0.9 Ω (0.027 Ω∙mm) with an OFF-state capacitance and resistance of 14.1 fF and 30 kΩ, respectively, were measured. This results in a switch cutoff frequency (Fco) of 12.5 THz, with an OFF/ON resistance ratio of 10,000:1. This represents the highest reported Fco on chalcogenide switches to date. The threshold voltage (Vth) for these devices was measured at 3V and the measured third-order intercept point (TOI) was 72 dBm. Single-pole, single-throw (SPST) switches were fabricated, measuring 0.15 dB insertion loss in the ON-state, and 15dB isolation in the OFF-state at 18 GHz. The IPCS SPST switches were fabricated using a complete backside process with through-substrate vias, demonstrating their viability for use in low loss, non-volatile, zero power consumption RF circuits.

A design method for BAW filters based on intrinsically switchable ferroelectric BST FBARs is presented. A complete set of design equations for ladder-type FBAR filters is derived based on popular filter synthesis method using image parameters. For the first time, the complete analysis is performed that accurately calculates both image impedance and propagation constant for BAW filters. Closed-form design equations as a function of FBAR and filter specifications are provided. As an experimental verification, a 1.5-stage switchable ferroelectric BST FBAR filter is designed, fabricated, and measured. When a dc bias is applied, a switchable filter is in its on state and provides an insertion loss of 5.77 dB with a fractional bandwidth of 1.22% at 1.97 GHz. When in its off state, the filter exhibits more than 22 dB isolation. Circuit-level simulation results are in very good agreement with the measurement results, validating the proposed BAW filter design method.

This work discusses a new class of Aluminum Nitride (AlN)-based filters and duplexers for operation in the microwave frequency range. These novel devices are based on the use of recently developed Cross-Sectional-Lamé-Mode resonators (CLMRs), thus enabling a wideband operation (Bandwidth (BW) >20 MHz around 1 GHz) thanks to their high electromechanical coupling coefficient (kt2>6%). In addition, as their resonance frequency can be defined lithographically, CLMRs enable the monolithic integration of multiple contiguous or non-contiguous filters to be used for carrier-aggregation in next-generation LTE-A platforms. Furthermore, a novel device architecture enabling reconfigurability of AlN-based resonators is also presented. This is based on the use of Phase Change Material (PCM) switches monolithically integrated with AlN piezoelectric micro-acoustic resonators. We experimentally demonstrate that this novel reconfiguration strategy enables the dynamic control of the key-features of AlN-based filters without significantly increasing the complexity of the device fabrication process and substantially degrading the device performance.

In recent years, the mobile data traffic is increasing and many more frequency bands have been employed. A simple Pi type tunable band elimination filter (BEF) with switching function is investigated by using a wideband tunable surface acoustic wave (SAW) resonator circuit. The frequency of BEF is tuned approximately 31% by variable capacitors without spurious. In LTE low band, the arrangement of TX and RX frequencies is to be reversed in Band 13, 14 and 20 compared with the other bands. The steep edge slopes of the developed filter can be exchanged according to the resonance condition and switching. With combining the TX and RX tunable BEFs and the small sized broadband circulator, a new tunable duplexer is experimented that the TX-RX isolation is more than 50dB in LTE low band operations.

Two-port, tunable interdigital capacitors (IDC) were fabricated on perovskite oxide thin films. The devices utilize electric-field tunable Ba0.29Sr0.71TiO3 (BST) thin films grown by hybrid molecular beam epitaxy (MBE) on LaAlO3 (LAO) substrates. A high-quality interface was achieved by hot-sputtering epitaxial platinum. The devices were measured from 100 MHz to 40 GHz and the results fitted to a frequency-dependent RLC equivalent circuit model. High quality factors (200) combined with 47% tunability were demonstrated in the S/L-bands. The devices exhibit a commutation quality factor averaging 6,000 across the L band which surpasses any previous results in this band. A phase shifter unit cell was simulated and implemented using the IDC equivalent circuit parameters.

Electric-field-induced, anharmonic dipolar resonances of room-temperature, barium strontium titanate (BST) thin film varactors have been used to rectify and detect microwave signals with frequencies ranging from 2GHz to 3GHz. The resonant frequency was shown to have strong dependence on film thickness with some amount of voltage-controlled tunability. Our experiments involved lock-in detection of a 100% amplitude modulated microwave signal with power levels ranging from -20 dBm to +10 dBm. An on-resonant sensitivity of 0.6 mV/mW was observed. This power detection sensitivity was shown to have built-in bandpass filtering corresponding to the resonant line shape.

A method for the design of a conical to coaxial transmission line transition with an arbitrary smooth impedance profile is presented. This type of transition is often used in conical line combiners, and has previously either had a constant impedance or an impedance taper that could not be explicitly designed. The presented method provides the designer with more design freedom by allowing an arbitrary impedance profile to be chosen or optimized and the resulting physical dimensions determined, instead of having to change the physical dimensions of the transition and then determine the resulting impedance profile afterwards. A conical combiner with improved performance is designed using the presented method. The performance predicted by the circuit model is in good agreement with full-wave simulations and measurements.

This paper presents a predictive model for Slow-wave Coplanar Striplines (S-CPS). A Quasi-TEM propagation mode has been assumed for developing the equivalent electrical model. Based on the geometries and the definition of the back end of line, the model is capable to fully predict the behavior of the S-CPS without any fitting parameters. The model was validated with measurements of S-CPS implemented in the 0.35-µm CMOS AMS technology. A good agreement is achieved between the model and measurements in a wide band (DC-40GHz). This model provides the designer a powerful tool for fast design of differential circuits, for which the use of S-CPS instead of microstrip lines can be very efficient.

To miniaturize the conventional air gap waveguide (GW), a substrate integrated gap waveguide (SIGW) is proposed. And moreover, it makes up the defects in the microstrip-ridge air GW, such as inconstant gap height, holes in strip, as well as strip electroless nickel immersion gold (ENIG) coating. To verify the proposed SIGW, a prototype was designed and fabricated using multi-layer printed circuit board (PCB) technology. It includes a very simple deign of the transition between SIGW and microstrip lines for measurements. And the experimental results show that the measured performance agrees well with the simulated.

A class of transformative transmission lines and waveguides called mode-selective transmission line (MSTL), is devised and demonstrated in this work. MSTL, in a fully integrated form, exhibits a disparate modal characteristic of traditional planar microwave transmission lines and non-planar waveguides. Whereas at low frequency, MSTL operates under the TEM regime, the operating mode is gradually converted to low-loss TE10 mode for operation as frequency moves up such as millimeter-waves and THz. An experimental MSTL prototype on fused silica substrate is designed, fabricated, and measured from DC to 500 GHz, showing unprecedented low-attenuation and low-dispersion characteristics over the entire frequency range.

A novel compact tri-passband bandpass filter is proposed and developed. The proposed filter consists of two hexagonal grounded resonators, one rectangular slot, and two hexagonal patches. The resonators, slot and patches can control three passbands with 3, 5.5, and 9.4 GHz for central frequency, respectively. The equivalent circuit and design procedures of the tri-passband bandpass filter are provided as well.

In this paper, a seven-pole balanced filter is presented with sharp skirt and extended upper-stopband in differential-mode (DM) response. Based on slotline resonator published in previous works, boundary conditions are briefly discussed in order to explain the mechanism of multi-mode DM transmission and intrinsic high common-mode (CM) suppression in the microstrip-slotline (MS) conversion. Then a λ/2 stepped-impedance resonator (SIR) is loaded on the center of traditional slotline resonator for enhanced DM selectivity. Several T-shape and L-shape short-circuited stubs are introduced for extended DM upper-stopband. The proposed balanced filter is further simulated and optimized afterwards. Finally, simulated results of the proposed filter show good performances such as 7-mode bandpass response with enhanced selectivity, extended upper-stopband rejection and intrinsic high CM suppression.

A microstrip balanced quad-channel diplexer is reported for the first time, using dual-open/short-stub loaded resonator (DOSLR/DSSLR) which consists of a uniform impedance end-shorted resonator loaded with two open/short stubs. The resonant frequencies of dual-open-stub loaded resonator (DOSLR) and dual-short-stub loaded resonator (DSSLR) under differential-mode (DM) and common-mode (CM) excitation are fully analyzed. Based on their respective characteristics, two individual balanced dual-band filters are initially designed with a frequency ratio of larger and smaller than 2 respectively. The designed filters are then combined to construct the first balanced quad-channel diplexer adopting distributed coupling technique. In order to demonstrate the efficacy of the proposed design methodology, a compact quad-channel balanced diplexer prototype (2.4/5.2 GHz and 3.2/4.75 GHz) is implemented and measured. Good agreement between the theoretical analyses and the measured data has been achieved.

This paper presents a novel substrate integrated waveguide (SIW) filter, based on quarter-mode cavities, which permits to obtain a transmission zero close to the passband. The use of quarter-mode cavities provides a significant size reduction compared to regular SIW cavities, while preserving most of the advantages. The proposed filter comprises four side-coupled cavities, and the use of cross-coupling permits to introduce the transmission zero. The cross-coupling is due to thin metal strip outside the cavities, and it can be easily controlled to locate the transmission zero at the desired frequency. A four-pole filter operating at frequency of 4 GHz, with a transmission zero very close to the passband, was fabricated and measured. The proposed filter has a footprint of 41×28.5 mm2, corresponding to 0.55 λ0×0.38 λ0, where λ0 is the wavelength in vacuum at 4 GHz.

A multilayer combline filter with high harmonic suppression is presented.The filter utilizes multilayer capacitors and coupled stripline resonators.It has high selectivity and high harmonic suppression. Harmonics aresuppressed by using amultilayer structure that can be built by standard printed circuit board fabrication process. A good agreement between simulation and measurementresults is achieved.The proposed filter shows harmonic rejection up to 5 times the center frequency.

This paper discusses design techniques for multiband filters presenting two miniature configurations for a triple-band high temperature superconductor filter designed to meet the requirements of the Link-16 system. The first design employs a triplexer approach while the second design integrates a dual-band reject filter with a wideband bandpass filter. Simulation and measurement results are presented for both designs with a discussion on the suitability of multiband design techniques for implementation in high temperature superconductor technology. The measurement results demonstrate the feasibility of realizing more than 60 dB rejections between the three bands.

A planar filtering crossover is proposed for three intersecting channels in this paper. It is constructed with three dual-mode ring resonators. The even and odd modes are coupled in three groups, to support the second-order bandpass filtering response for each channel. The isolation between different channels are achieved by using the orthogonality of even and odd resonant modes, with properly designing the internal and external couplings. The prototype shows reasonable performance of both intra-channel filtering and inter-channel isolation.

This paper presents a balanced-to-balanced power divider (PD) with common-mode (CM) noise absorption for the first time. By properly adding the λ/4 transformers and resistors at the input-/output ports of back-to-back PD, the proposed balanced-to-balanced PD can achieve CM noise absorption while keeping its differential-mode (DM) characteristics. The measured results at 2.55 GHz show that reflection and transmission coefficients for CM operation are all less than –30 dB, while less than –30 dB and better than –4 dB for DM operation.

This paper presents a compact device with functions of frequency selecting and power dividing simultaneously. Open-stub loaded dual-mode resonators are selected as the basic building blocks. By cascading two dual-mode resonators, a novel fourth-order inter-cross-coupled coupling scheme containing mixed coupling is realized and employed to replace the λ/4-line sections of conventional Wilkinson power divider to improve out-of-band rejection performance. Two surface mounted resistors of different values are placed between channels to obtain high in-band isolation between output ports. Furthermore, a filtering PD operating at 4.45 GHz is designed, fabricated and tested to demonstrate the efficacy of the proposed design. Four finite transmission zeros positioned at 3.85 GHz, 4.25 GHz, 4.75 GHz and 5.4 GHz respectively are achieved which will result in good frequency selectivity. Very good agreement is observed between the simulated and experimental results with approximately 1.3 dB insertion loss and over 18 dB isolation over the entire passband.

The work proposes a general model for the transmission line miniaturization equivalent. Solutions with different configurations can be readily found. The model is applied to the design of branch-line couplers, and design criteria are presented and analyzed. Previously reported approaches can be obtained by simply changing parameters using the general model. A 2GHz branch-line coupler is designed and fabricated to demonstrate the efficiency of the new method. A 900MHz branchline coupler from literature is re-designed and analyzed to show the differences between the proposed method and the previous work.

This paper presents a transformer based N-way Wilkinson power divider. The λ⁄4 transmission lines in a conventional N-way Wilkinson divider are replaced by a fully symmetric N-coil transformer. The proposed design features low insertion loss as well as good input/output matching in an ultra-compact chip area. By adding cancellation capacitors, excellent isolation is achieved between any two output ports. Through even- and odd- mode analysis, the closed-form design equations are derived and presented. As a proof-of-concept demonstration, a four-way transformer based Wilkinson power divider is implemented at 4.60GHz in a standard 130nm bulk CMOS process. The measurement results demonstrate 1.10dB insertion loss, 17.0dB isolation, and 20.9% bandwidth, advancing the state-of-the-art performance of fully integrated Wilkinson power dividers.

A coupled-Gysel broadband combiner/divider is proposed and demonstrated. The new concept relies on using a single coupled line segment in the design. Significant improvement in bandwidth are realized while maintaining low-loss, ease of design, and flexibility. The coupled-Gysel is demonstrated with a 2.5 – 8 GHz (105% fractional bandwidth) divider with 0.1 dB divider loss, and a 3.4 – 10.2 GHz (100% fractional bandwidth) with 0.2 dB divider loss.

In this paper, a novel approach to design a power divider with the predefined negative group delay (NGD) is presented. The proposed topology is based on a coupling matrix with a finite unloaded quality factor (Qu) of resonators, which does not require any lumped elements such as resistor for generating NGD. The NGD bandwidth and magnitude flatness can be controlled by inter-resonating couplings. As an experimental illustration, a microstrip line NGD power divider is designed and fabricated at center frequency of 2.14 GHz. The measurement results are in good agreement with simulations.

The use of a power-dependent coupling structure that allows a cul-de-sac bandstop filter topology to continuously transform between a resonant all-pass response and a bandstop filter response with increasing input power is shown. In contrast to limiter devices that provide a wideband short circuit or ferrite resonance under high-power excitation, the concept presented in this paper provides the ability to design limiters with frequency selectivity and without magnetic materials. For verification, a third-order power-dependent bandstop filter was designed and fabricated. It has a center frequency of 1.95 GHz, 3 dB bandwidth of 400 MHz, 1 dB limiting threshold of approximately 21 dBm, a response time of 10 ns, and provides over 12 dB of limiting.

Hybrid acoustic-wave-lumped-element resonator (AWLR)-based bandpass filters (BPFs) with reconfigurable bandwidth (BW) and tunable out-of-band isolation (IS) are reported. They are based on a new BPF architecture in which AWLRs are in-parallel cascaded to an all-pass network through variable lumped-element inverters. In this manner, passbands with arbitrarily-large BW─i.e., no longer limited by the electromechanical coupling coefficient (kt2) of its constituent acoustic-wave resonators (AWRs)─can be created and controlled whilst preserving the high-quality-factor (Q: order of 10,000) characteristics of the AWR. Furthermore, tuning of the IS is obtained by adjusting the location of the AWLRs transmission zeros (TZs: 2N for an N-pole BPF) through variable capacitors. The operating principles of the devised AWLR-based tunable BPF concept are experimentally validated through a three-pole/six-TZ prototype at 418 MHz made up of commercially-available surface-acoustic-wave (SAW) resonators. It exhibits tunable BW between 0.16-0.49 MHz (0.5-1.5kt2), minimum in-band insertion loss between 3.3-1.2 dB (Q>10,000), and out-of-band IS reconfigurability.

In this paper, a very compact tunable diplexer is proposed with controllable transmission zeros and controllable output isolation levels. The two channels in the diplexer can be independently tuned and cover a tuning range from 1.9GHz to 3.4 GHz. Controllable transmission zeros are introduced in each channel by using the source-to-loading coupling. The introduced transmission zeros cannot only be used to improve the channel selectivity, but also used to improve the output isolation levels during frequency tuning. An output isolation level of >48 dB is achieved during each tuning state.

A new class of planar multi-band bandstop filters (BSFs) with spectrally-agile stopbands in terms of center frequency and bandwidth are presented. They are based on the in-series cascade of several frequency-reconfigurable multi-stopband filtering sections. Each of these sections is shaped by N tunable resonators (center-frequency control) that interact with the same non-resonating node (NRN) through independently-controlled impedance inverters (bandwidth reconfiguration) for an N-band BSF response. Additional features of this filter approach are: i) independent control of each rejection band with no influence on the others, ii) stopband-merging capability to attain controllability in the number of generated stopbands along with increased bandwidth flexibility for them, and iii) concept scalability to any number of stopbands and poles. Its operational principles are theoretically demonstrated through the coupling-matrix formalism for the engineered multi-band BSF. Moreover, for experimental verification, a mechanically-reconfigurable three-band BSF microstrip prototype in the 0.9-1.2-GHz frequency range was manufactured and characterized.

Multi-functional low-pass-filters (LPFs) with dynamically-controlled in-band rejection-bands are reported. They are based on series-cascaded RF-modules that functionalize low-pass (LP) transfer-function with/without an embedded absorptive-notch (AN). In this manner, multiple rejection-bands that exhibit theoretically-infinite attenuation and don’t affect the passband loss (IL) are incorporated within a highly-selective-LPF that features smaller size and lower IL than conventional cascades of individual filter blocks. Further advantages include: i) scalability to arbitrary number of rejection-bands, ii) independent control of ANs in frequency and isolation (IS), iii) the ability to control the number of active in-band notches. The concept is validated through a manufactured-prototype with two tunable-ANs. They are located within a low-IL (

This work covers the design and measurement of a low cost tunable impedance matching network (TMN) for highly linear and high power RF applications at telecommunication frequencies. A single transistor cell, was wire-bonded to a TMN and the performance of the tunable amplifier module was evaluated from 1 GHz to 2.5 GHz. The TMN transforms the GaN HEMT output impedance to fixed 50 Ohm load. Tuning allows efficient operation of the transistor over the targeted frequency range. Peak drain efficiency of 66% and a peak output power of 37.5 dBm were measured. Two-tone measurements reveal an OIP3 around 47 dBm which is comparable to a bare GaN HEMT.

A new class of frequency-agile single/multi-band planar real-impedance transformers that feature bandpass filtering capabilities for their operative bands are proposed. They are based on the incorporation of single/multi-band quasi-bandpass filtering sections into a wide-band impedance transformer whose operational range covers the intended frequency-tuning range of the individually-controlled passbands. Thus, by controlling the natural frequencies of the resonators in these sections through variable capacitors, a tunable single/multi-band impedance-transformation/bandpass-filtering action is obtained. The operational foundations of this reconfigurable dual-function device, which can be applied to designs with an arbitrary number of bands, are expounded. Furthermore, as experimental demonstration, a three-band microstrip prototype with tunable bands throughout the range 1.2–1.8 GHz is developed and tested.

A matched load in substrate integrated waveguide (SIW) technology is presented at K-band. An embedded resistive thick film is used to absorb the input signal. The proposed structure is fully compatible with standard multilayer printed circuit board processes. The realized SIW termination exhibits a bandwidth of 2.75 GHz with a return loss of more than 20 dB around 18.4 GHz.

A broadband directional Moreno coupler consisting of a high performance Air-Filled Substrate Integrated Waveguide (AFSIW) coupled to a top Dielectric-Filled Substrate Integrated Waveguide (DFSIW) is introduced. It is intended for high performance and low-cost millimeter-wave substrate integrated systems based on multilayer Printed Circuit Board (PCB) process. Design of the proposed Moreno coupler is detailed. To the authors’ knowledge, it is the first time that a Moreno coupler based on different dielectric-loaded waveguides is reported. It is also the first proposed AFSIW device taking advantage of a multilayer structure and the first AFSIW directional coupler reported in the literature. For demonstration purposes, a broadband 20 dB coupler operating over Ka-band has been designed and fabricated. It achieves a measured insertion loss, coupling and isolation of 0.6 ±0.2 dB, 18.7 ±1.3 dB and 44.7 ±13.7 dB, respectively. This coupler is of particular interest for monitoring applications, for example, in radar transmitters.

A compact wideband and high performance helical resonator diplexer is proposed in this paper. The lower and upper bands of 690MHz – 803MHz and 824MHz – 960 MHz, respectively are achieved by two fifth order channel filters in a volume of 160 × 40 × 30 mm3. The insertion loss is less than 0.4 dB in both frequency bands and is better than 0.6 dB at the band edges. An isolation level of 30 dB is realized. A novel technique to effectively increase the I/O coupling by shunt connecting a capacitor at an I/O structure is proposed for the first time and applied in the helical diplexer design. The technique can be applied to other wideband coupled-resonator filters/diplexers.

This paper presents the design, manufacturing and testing of a new type of compact and low loss Ka-band filter in multilayer micromachined technology. It consists of a 4th order pseudo-elliptic filter realized by stacking six silicon layers for a reduced footprint. The filter is based on λ/2 TEM Si membrane resonators placed inside shielding cavities and short-circuited at both anchored ends. With respect to conventional cavities based on TE101 resonant mode, the footprint of the proposed resonators is reduced by more than 50% at the expenses of a reduced Q factor degradation (

This paper outlines a new class triple-band bandpass filters employing cavities that resonate in three orthogonal modes. The proposed design can achieve equivalent performance with fewer cavities, thus significantly reducing the size and footprint when compared to traditional approaches. The concept is applicable to all triple-band cavities as demonstrated in this paper using rectangular waveguide cavities. The proposed triple-band filter offers increased Q and allows for independent control of each frequency and coupling parameter. A 4th order C-band triple-band filter is designed, manufactured, and tested to validate the proposed concept. To the best of authors’ knowledge, this is the first triple-band filter realized with a cavity structure.

We present in this paper a novel canonical folded prototype circuit with some couplings varying linearly with the normalized frequency. The derivation of this prototype is based on a suitable transformation of an asymmetric lattice network, generated through a sequence of matrix rotations of the coupling matrix of the folded canonical prototype. It is shown that the lattice network is a generalization of the canonical cul-de-sac form, which is obtained when the reflection zeros are all imaginary. We have also verified that the cul-de-sac forms are possible only when the reflection zeros are all imaginary (or in para-conjugate pairs). The lattice network (or the one with frequency-dependent couplings) represents a possible alternative to the cul-de-sac forms in the synthesis of star-junction multiplexers, when the synthesized filters exhibits complex reflection zeros

In this paper a new class of in-line filters with pseudoelliptic responses based on mixed-mode resonators is presented. The mixed-mode resonator consists of a cavity with a suspended high permittivity dielectric puck at its center. Both cavity TE101mode and dielectric TE01d mode are exploited. This structure realizes the transverse doublet topology and it is capable of a transmission zero that can be easily positioned in both upper and lower stop-band. Coupling are controlled by both irises width and puck rotation. Mixed-mode resonator can be used as building block to obtain higher order filters by cascading them through non-resonating nodes. Such filters are capable of transmission zeros very close to the pass-band, resulting in a very high selectivity. Furthermore the presence of the dielectric puck leads to a very compact structure with a stable behavior in temperature.

In this paper a new approach for the design of very compact bandpass filters (BPFs) with transmission zero generation is proposed. The proposed filters are based on a dual mode substrate integrated waveguide (SIW) coaxial cavity. This filtering building block provides two coaxial modes performing a doublet filtering configuration. The proposed dual-mode SIW coaxial cavity is studied in detail and guidelines for the filter design are given. As will be shown, the proposed building block presents a high degree of design flexibility, which allows for the design of multiple kind of bandpass filter responses, including both narrow- and wide-band bandpass filters along with TZ generation. Two proof-of-concept filters are implemented and tested: a wide-band BPF with a fractional bandwidth of 20\% centered at 8 GHz, and a quasi-elliptic type narrow-band BPF formed by cascading two dual-mode SIW coaxial cavities.

A novel planar-filter realization of a fully Canonical order Cul-de-Sac coupling matrix that can produce the maximum number of transmission zeros (TZs) is proposed in this paper. It is known that a transversal array coupling topology that offers a generalized Chebyshev function response is hard to design in a physical structure, owing to simultaneous excitation of resonators. To overcome such a drawback, this paper introduces a fully canonical Cul-de-Sac coupling that can be obtained with mathematical transformation from a transversal array coupling. The proposed filter structure has two resonator blocks: one is a block of even-mode half-wavelength resonators, and the other is a block of odd-mode ones. The filter can be easily designed by coupling coefficients between two adjacent resonators without any cross couplings. The effectiveness of the proposed filter is verified with synthesis, design, and test of a 2-GHz fourth-order microstrip filter with four TZs.

An aggressive space mapping (ASM) method is presented for coupled-resonator filters specified by coupling matrices when two additional, geometry-based models are available: one precise but expensive and a lower-cost one. The method combines two levels of ASM between the three models, avoiding direct optimizations of the network response, and also costly computations of Jacobian matrices. The algorithm is illustrated with a microstrip coupled-line bandpass filter with cross-coupling and ten geometrical parameters, that is adjusted in only two iterations.

A direct synthesis and design approach to lowpass filter (LPF) with ultra-wide stopband is proposed. The LPF consists of multiple radial stubs and capacitively loaded stubs, all connected by high impedance transmission lines in cascade. The capacitively loaded stubs with long electrical lengths not only produce transmission zeros (TZs) close to band edge to sharpen the roll-off, but also produce TZs in the far stopband. The radial stubs, which can be well approximated by series LCs and are spurious-free in a wide frequency range, are used to generate extra controllable TZs in the far stopband. The layout of LPF can be accurately modelled by a mixed lumped/distributed (MLD) equivalent circuit, which can be systematically converted from a generalized Chebyshev lowpass prototype. To demonstrate the proposed design approach, a 17-degree lowpass filter with cut-off frequency fc of 2 GHz and approximately 40 dB rejection stopband up to 9 fc is presented.

This letter presents a first-order reflectionless lumped-element lowpass filter (LPF) and bandpass filter (BPF) design method. The proposed filter structure includes a shunt connected impedance matching circuit which can theoretically cancel the reflected wave out generated inside a filter structure. Using ABCD matrix, the proposed filter structure has been designed analytically and all elements value can be obtained from the conventional first-order low-pass prototype element based on the simple design equations. Both conventional and proposed filter structures for the lowpass filters (LPFs) and the BPFs are designed and manufactured to support the presented design theory. The experimental results show that the proposed filter structures achieve the improved return loss characteristic at the input port while it exhibits the same transmitted power ratios with the conventional filter structures.

Fully-passive two-branch channelized circuit configurations for high-selectivity planar filter realization are reported in this work. They exploit the in-parallel connection of two frequency-contiguous low-order passive filters—main and auxiliary channels—to synthesize an enhanced-selectivity filtering response by means of signal-interference principles. Added features of the channelized passive filter in relation to its building channels are: i) bandwidth enlargement of the overall transmission band and ii) the generation of reconfigurable notches in the transfer function of the main channel for dynamic interference suppression by detuning the poles of the auxiliary channel. As experimental proof-of-concept, two microstrip prototypes consisting of a frequency-static quasi-elliptic-type lowpass filter and a bandpass filter with tunable-dual-notch creation capability through mechanically-adjustable capacitors are built and tested.

Direct synthesis technique for coupling matrix of mixed topology filters that contain cross-coupled structures and a series of extracted-pole sections is proposed and demonstrated. Instead of evaluating elements one by one in conventional synthesis, the canonical coupling matrix, including all the cross-coupled and extracted-pole couplings, can be solved one time by using the proposed technique. The direct synthesis is based on a process for the admittance function construction of a filter, yielding a mixed topology prototype where one or more extracted-pole sections are generated at the source port naturally. A sixth-order filter is carried out as an example, which verifies the validity of the proposed technique.

This paper presents a fourth-order synthetic Q-enhanced LC band-pass filter (BPF) in 0.13 μm SiGe BiCMOS, where 4th-order BPF response has been synthesized by subtracting two 2nd-order BPF responses. Operating frequency of the filter is tunable from 4-8 GHz. Using a switched-varactor control for a high linearity, the filter achieves 150-166 dB∙Hz normalized dynamic range (DR) with a tunable fractional bandwidth range of 2-25% at the center frequency of 6 GHz. The ultimate out-of-band rejection of the filter is > 65 dB and > 52 dB on the lower and upper side of the center frequency, respectively. The filter consumes 112-125 mW of DC power dissipation. The core chip size is 0.53×0.7 mm2.

This paper presents a novel design of a highly tunable active bandpass filter with adjustable notches close to the passband. The filter is based on two-path signal cancellation and consists of a tunable bandpass filter in parallel with a tunable bandstop filter. This combination ensures the correct amplitude and phase relationship across a wide tuning range to create adjustable transmission notches without sacrificing the gain of the passband. The proposed filter is implemented with high-Q N-path filter/resonator blocks in a 65-nm CMOS process. The passband of the filter is tunable from 0.2 GHz to 1.2 GHz with a 3-dB bandwidth of 5.8–6.2 dB, a gain of 18.5–21 dB, a noise figure of 4.5–6.2 dB, and a total power consumption of 33–70mW. The blocker 1-dB compression point is 8 dBm and the out-of-band IIP3 is 18 dBm. The reported filter provides a promising solution to multi-standard, multi-frequency software defined radio applications.

We present the miniaturized RF tunable band-pass filter based on magnetoelectric NEMS coupled ring-shaped FBAR resonator with contour mode of transmission. The acoustic wave can be strongly coupled with the radiation electromagnetic wave due to the strong magnetoelectric effect between the piezomagnetic FeGaB and piezoelectric AlN thin film. For the FBAR resonator, a return loss of -11.15 dB and insertion loss of 3.57 dB with high quality factor of 252 can be achieved at 93.165MHz. The band-pass filter performs sensitive magnetic field dependence with ~0.5% magnetic field tunability of the operation frequency.

An ultra-wideband (UWB) bandpass filter (BPF) with super compact circuit size is proposed, which is realized using bridged-T coils. By replacing all the transmission line sections of a tri-mode resonator with bridged-T coils, the filter size can be largely reduced while the original frequency response remains almost intact. The proposed filter structure can then be conveniently realized with semiconductor IC process to achieve super compact circuit size. Specifically, an UWB BPF with a passband from 3.1 to 10.6 GHz is demonstrated using a commercial GaAs pHEMT process. The circuit size is 0.88 mm×0.88 mm, which is only about 0.02λ0×0.02λ0 at f0 = 6.85 GHz. To the best of our knowledge, this is the smallest UWB BPF ever reported.

A bandpass single-pole-double-throw (SPDT) switch with very compact size is proposed, which is realized using a capacitvely loaded multicoupled line. By sharing the first resonator between the two signal paths and by replacing the quarter-wavelength impedance transformer in conventional designs with a J-inverter, the circuit size can be much reduced. In addition, the capacitive loading help improve the spurious response such that a very wide upper stopband up to 10f0 is achieved. Specifically, a third-order bandpass SPDT switch with f0 = 5.5 GHz and a bandwidth of 10% is realized in a commercial GaAs pHEMT process. The measured in-band insertion loss in the on state is better than 4 dB with a 30-dB upper stopband up to 55 GHz. The measured isolation in the off state is better than 30 dB from dc to 55 GHz. The chip size is 1.5 mm×1 mm, which is only about 0.028λ0×0.018λ0 at f0.

A new passively-compensated coupling structure amenable to use in evanescent-mode cavity resonators capable of producing constant absolute bandwidth over wide tuning ranges is presented for the first time. It is used to realize a constant absolute bandwidth 2.0-4.2 GHz tunable bandstop filter which utilizes evanescent-mode cavity resonators. The filter has high levels of stopband rejection (> 50 dB) across its entire tuning range, and has a 54.5 ± 6.5 MHz 3-dB fractional bandwidth. When compared to the coupling method traditionally used for evanescent-mode resonators, the proposed method reduces the bandwidth variation of this filter from 295% (21 to 83 MHz) to 27% (48 to 61 MHz).

An original fully-reconfigurable bandpass filter (BPF) is presented. It consists of two series-cascaded spectrally-overlapped second-order BPFs and a filtering cell that generates two transmission zeros (TZs) for selectivity enhancement. The three inter-cascaded filtering blocks comprise six frequency-tunable resonators that interact through static impedance inverters. By controlling the natural frequencies of all resonators through variable-reactance elements, an overall frequency-agile bandpass response in terms of center frequency, bandwidth, and TZs is attained. Furthermore, since the passband-width is controlled without altering the inter-resonator couplings, benefits are obtained in terms of lower in-band insertion loss and larger bandwidth tuning ratio that can be reduced to zero (i.e., intrinsic switching-off state). The operating principles of the devised filter concept are expounded. Also, an evanescent-mode cavity-resonator prototype with tunable response in the range 2.9-3.5 GHz is built and tested. The developed circuit demonstrates one of the highest electronic-reconfiguration capabilities reported up to date for 3-D BPFs.

This paper presents, for the first time, a magnetostatically tuned capacitive-post loaded evanescent-mode cavity filter for C-X band reconfigurable RF-frontends. The measured device is a two-pole Butterworth bandpass filter that demonstrates an analog tuning from 6.8-13.2 GHz (1:1.94 tuning ratio) while maintaining a near-constant 1% fractional bandwidth. The filter insertion loss varies from 4.2-1.8 dB (including connector losses) from the lowest to highest frequency, which corresponds to an unloaded quality factor of 300-700. The filter has an overall size of

This paper presents a novel design of a highly tunable dual-band bandpass filter based on evanescent-mode cavity resonators with two capacitive loadings which results in two independently tunable resonant frequencies. High unloaded quality factor, for both resonant modes, and small filter size is achieved since the two modes share the same physical volume of a single cavity. In addition, the internal and external couplings of the filter can be controlled independently at the two passbands to create flexible frequency responses. An example design of the proposed filter is prototyped in a substrate-integrated fashion and demonstrates: 1) a first tunable passband of 1.156–1.741 GHz with 3-dB bandwidth (BW) of 76–156MHz and insertion loss (IL) of 3.13–1.109 dB, and 2) a second passband of 2.242–3.648

A compact size 800MHz band-pass filter (BPF) design fabricated with a High Resistivity Silicon Integrated Passive Device (IPD) process is presented in this paper. Insertion loss < 2.2 dB with reasonable filter rejection is achieved in a standard 01005 size. The proposed design provides good separation from multiple bands such as Mobile Radio, UHF low band, 2.4GHz ISM, and WiMAX applications. Here we discuss the IPD design procedure, simulation and model correlation results through on wafer measurement. Performance variation by packaging option is also discussed.

An ultra-compact integrated resonator and bandpass filters (BPF), in silicon-based technology, are presented for millimetre-wave applications. The resonator consists of two broadside-coupled lines in opposite orientations. Using this resonator, a first-order and a second-order BPFs were also designed. To prove the concept, three prototypes of each of the resonator and the first-order BPF were fabricated using a standard 0.13-μm SiGe process. The measured results show that the resonator has an attenuation of 13.7 dB at the resonance frequency of 57 GHz, while the BPF has a centre frequency of 31 GHz and an insertion loss of only 2.4 dB. Excluding the pads, the chip size of both the resonator and the BPF is extremely compact, only 0.024 mm2 that is equivalent to 0.001 λg2. The unloaded Q factor of the filter is higher than other state-of-the-art designs.

Two millimeter-wave dual-mode ring-based filters implemented in SiGe BiCMOS 0.25-µm technology are presented. Both filters are designed using specific synthesis. The nominal ring filter exhibits 12.1% of 3-dB fractional bandwidth (FBW3dB), 5.6 dB of insertion losses at 61 GHz for a footprint of 0.74 mm². The modified filter is a capacitively loaded ring filter showing 11.5% of FBW3dB, 5.5 dB insertion losses at 62 GHz with a footprint of 0.32 mm². The modification allows a significant size reduction (2.3 times smaller) while maintaining equivalent electrical performance.

STRACT— A miniaturized multi-layered wideband bandpass filter (BPF) based on the low-temperature-cofired ceramic (LTCC) technology is proposed in this paper. The proposed filter consists of a T-shaped short stub and a pair parallel transmission lines. Owing to the multi-path effect, multiple transmission zeros can be realized near the passband for enhanced selectivity. A wide-band filter from 3.59GHz to 8.21 GHz is designed, fabricated and measured.The measured results show that the center frequency is 6 GHz with a fractional bandwidth (FBW) of 74.8%. Three transmission zeros were introduced near the passband, located at 2.1GHz with 36.25dB rejection, 9.25GHz with 27.02dB rejection, 10.56GHz with 28.58dB rejection. Index Terms — BPF, LTCC, T-shaped short stub, multiple transmission zeros , wide-band filter.

A compact microstrip bandpass filter with a wide passband and broad stopband is proposed. In order to miniaturize the circuit size, the interdigital capacitor is adopted. Moreover, the open- and short-circuited coupled lines are also employed to generate the transmission zeros around the passband skirts. This bandpass filter is developed at 2.45 GHz for the central frequency. The measured bandwidth is 45% with 10-dB for the return loss. Furthermore, the stopband can be extended to 11.7 GHz (4.8f0) with the suppression of 27 dB.

This paper is focused on the application of electromagnetic bandgaps based on capacitive loading to the implementation of microstrip coupled line bandpass filters with reduced size and spurious suppression. Size reduction is due to the slow-wave effect caused by the loading capacitances of the different coupled lines, whereas spurious suppression is related to periodicity. By properly designing the capacitively-loaded coupled line sections of the filter, implemented by means of square patches in practice, it is possible to significantly reduce filter size and simultaneously achieve spurious cancellation. As an example, an order-3 Chebyshev bandpass filter with 30% length reduction (as compared to the conventional counterpart) and spurious rejection up to the third harmonic is reported.

A surface mounted waveguide (SMW) resonator filter, embedded in substrate integrated waveguide (SIW) technology, is presented. It is designed by using a mode-matching technique (MMT) together with extracted pole filter synthesis. The center frequency is set for K-band operation. The filter consists of three individual resonators and exhibits a high unloaded Q factor compared to other SMW and regular, pure SIW filters. Simulation and measurement data are in good agreement. Additionally, a study on the resonator height is included. The presented filter is easy scalable and adaptable to low cost, high volume production by employing standard printed circuit board (PCB) processing technology.

High-performance diplexers are frequently used in satellite systems to isolate the high-power wideband transmission band from the sensitive reception frequency-range. A compact broadband waveguide diplexer to cover the Ku transmission and reception bands (overall bandwidth up to 50 %) is proposed. It consists of an E-plane T-junction which branches to a very compact high-power low-pass filter and a band-pass filter based on inductive irises. The low-pass filter is based on λ/4-step-shaped bandstop elements separated by very short (ideally of zero-length) waveguide sections and provides the suppression of all higher-order modes. Its size is dramatically reduced compared to a classical waffle-iron filter or a corrugated filter of narrowed width. The band-pass filter has been also designed to minimize the overall footprint. The final diplexer has been manufactured. The measured frequency response confirms the simulations taking into account rounded-corner effects demonstrating that this approach fulfills stringent specifications with a very compact implementation.

In this work, a direct synthesis approach based on the power wave renormalization theory is proposed for designing a filter that matches to complex frequency variant loads at both ports. It is shown that a network consisting of an ideal filter cascaded with two pieces of transmission line of optimal lengths at each port can match to the complex loads over a certain frequency band with a best effort. The approach provides an analytical yet flexible way to synthesize parallel-connected dual-band filters (DBF) of either a symmetric or asymmetric filtering response with a precise control of filter’s topology. The effectiveness is demonstrated through an asymmetric DBF design example.

This paper proposes a new synthesis technique for extracted pole and non-resonating nodes (NRN) filter. The circuit elements can be set to the values extracted from the simulation of its electromagnetic (EM) model during the synthesis procedure. Accurate mapping relationship between the physical dimensions and prototype circuit can be achieved with the fully analytical approach. A three pole waveguide filter with one finite transmission zero is designed to illustrate the new procedure. A four pole waveguide filter with two finite transmission zeroes from literature is re-designed and analyzed to show the validity of the proposed approach, accuracy and key differences.

This paper presents a new cross-shaped TM010 dual-mode dielectric resonator which provides 28.8% and 78% volume reduction in comparison with two single-mode TM and one dual-mode TE dielectric resonator, respectively. Based on a design method which is improved to avoid the tuning efforts, three filters are designed. A comparison between simulation and measurement results verifies practically the concept of dual-mode operation and its application for filter design.

Abstract — The paper introduces the concept of hyperbolic reflections in order to complement the hyperbolic rotation matrices used in the lossy coupling matrix filter synthesis. A complex transversal coupling matrix representing a lossy filter is chosen and it is seen how by applying a succession of similarity transformations based also on hyperbolic reflections one obtains different results than by using hyperbolic rotations which are nowadays used in the coupling matrix reconfiguration. Finally a lossy symmetrical filter is designed and simulated based on a folded coupling matrix by shifting the losses into the first and last resonators of the filter