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Mobile and wireless communications are playing an irreplaceable role in our daily life. 5G is highly expected and can be considered as the convergence of mobile and wireless communications. This topic becomes one of the hottest research topics recently, and papers on this topic have been paid much attention. lists the top ten papers published in the IEEE Transactions on Microwave Theory and Techniques (TMTT) in 2019 with the highest numbers of Full Text View since published. Seven papers are about millimeter-waves (mm-waves), and because mm-waves multiple-input–multiple-output (MIMO) will be adopted globally, the 24.25–27.5-GHz band and 27–29.5-GHz bands are now approved worldwide as the standard 5G communication bands. The most popular paper is published by Asbeck et al. [item 1) in the Appendix] for mm-wave power amplifiers. [ABSTRACT FROM AUTHOR]

This paper introduces a novel compact ultralightweight multiband RF energy harvester fabricated on a paper substrate. The proposed rectenna is designed to operate in all recently released LTE bands (range 0.79–0.96 GHz; 1.71–2.17 GHz; and 2.5–2.69 GHz). High compactness and ease of integration between antenna and rectifier are achieved by using a topology of nested annular slots. The proposed rectifier features an RF-to-dc conversion efficiency in the range of 5%–16% for an available input power of −20 dBm in all bands of interest, which increases up to 11%–30% at −15 dBm. The rectenna has been finally tested both in laboratory and in realistic scenarios featuring a superior performance to other state-of-the-art RF harvesters on flexible substrates. [ABSTRACT FROM PUBLISHER]

Prospective authors are requested to submit new, unpublished manuscripts for inclusion in the upcoming event described in this call for papers. [ABSTRACT FROM AUTHOR]

Novel 2-D gray-scale inkjet printed microstrip line (MSL) terminations are presented in this paper. The proposed open-end type MSL termination is constructed of a lossy trace printed on paper and placed on a typical dielectric substrate with background. Optimal design guidelines are also discussed for attaining best absorption band given ink resistivity and termination size. Both fixed width and tapered width lines are presented, experimentally showing high absorption levels over a wide bandwidth. These simple to fabricate structures may find applications in scenarios where low-cost wideband planar terminations are needed. [ABSTRACT FROM AUTHOR]

The 2020 Asia–Pacific Microwave Conference (APMC 2020) was held in Hong Kong, SAR, China, on December 8–11, 2020. The conference was organized by the IEEE Antennas and Propagation (AP)/Microwave Theory and Techniques (MTT) Chapter of Hong Kong, and technically co-sponsored by the IEEE MTT Society, the IEEE AP Society, the State Key Laboratory of Terahertz and Millimeter Waves, City University of Hong Kong; the Department of Electrical Engineering, City University of Hong Kong; and the Department of Electronic Engineering, The Chinese University of Hong Kong. Out of 531 papers submitted, 402 papers were accepted for presentation at the conference and publication in the 2020 APMC proceedings. These papers have also been published online on the IEEE Xplore website. The technical program involved more than 1000 authors coming from 28 different countries/regions. [ABSTRACT FROM AUTHOR]

This paper presents the design of a broadband and high-power amplifier with bounded performance technique (BPT). Like the real frequency technique (RFT) or the simplified RFT (SRFT), BPT achieves broadband performance via matching at some in-band discrete real frequencies. It solves some design issues that are not addressed in the RFT and the SRFT. Among them are the inclusion of the design specifications in the device selection and design process and the possible degradation of operation metrics that are not optimized. BPT also avoids complicated analytic mathematics by using circuit prototypes. In this paper, we show the design of an amplifier with BPT. It has a 3-dB compression power of at least 100 W and a drain efficiency of at least 50% over the band 1–2.8 GHz or 94.7% fractional bandwidth. We also show the design of the same amplifier with the traditional SRFT and compare its expected performance with that designed with BPT. [ABSTRACT FROM AUTHOR]

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The increasing use of backscatter radio for pervasive Internet-of-Things systems as a low-power and low-cost communication scheme will result in dense deployments of tags that need to operate under bandwidth (BW) constraints. Typical backscatter tags and computational radio frequency (RF) identification systems are unnecessarily limited to modulating data with “ON–OFF” switching front-ends, which leads to extensive spectrum occupancy, due to the rectangular pulses. This paper sets the foundations to overcome these limitations and proposes designs of RF front-ends that are capable of varying the tag reflection coefficient in a continuous way over time. Arbitrary waveforms can be generated to perform pulse shaping on the backscattered signals, which require significantly reduced BW. The principles presented in this paper will enable sophisticated tags to perform complex modulation schemes under BW constraints, while maintaining a very low RF front-end complexity, using a single nonlinear component such as a p-i-n diode or field-effect transistor. Migrating the idea of pulse shaping from complex power-demanding active radios to such minimal RF front-ends will complete backscatter radio as a communication scheme for simple RF tags and sensors in large-scale deployments. Each tag becomes a miniature software-defined radio that implements diverse communication schemes with increased spectral efficiency. [ABSTRACT FROM PUBLISHER]

The article outlines the procure for the Paper Submission in Electronic Form for authors. Topics include the guidelines provided by the journal "IEEE Transactions on Microwave Theory & Techniques"; Microsoft Word is the preferred format for this final submission, page charges for traditional submissions.

The maximum efficiency point of an inductive power link depends on its load power consumption and the distance between the transmitter and the receiver. Matching networks (MNs) and adjustable ac–dc converters have been proposed in the literature as a means to achieve and track this maximum efficiency point. Most of the published papers in inductive power transmission only use one of these two methods without considering a joint design. In this paper, we analyze and compare both methods proposing a general joint design which exploits the advantages of each method. A proof-of-concept system was developed following the proposed flow, built and tested. This system, with a regulated output voltage, presents improvements in measured efficiencies of up to 80% (from 9.2% to 16%) at the largest distances, thus maximizing the distance range. The same approach can be used to maximize output dc voltage, instead of the link efficiency. The proposed system using our designed MN achieved a maximum output voltage that was 90% higher (from 1.36 to 2.59 V) than the case where only a step-up converter was used. [ABSTRACT FROM AUTHOR]

This paper proposes a new coupling matrix synthesis technique called the coupling matrix compression technique, which focuses on reducing the dimension of the $N+2$ coupling matrix. The presented coupling matrices can be compressed, and this technique can be used to design dual-mode resonators for high-isolation dual-band filters. One dual-mode resonator is represented as two closely coupled resonators when using this technique. The formulae for resonant frequencies and $\omega _{m}$ in dual-mode theory are also derived in this paper. A dual-mode embedded hairpin resonator is designed and analyzed using this technique, and a dual-band filter using the proposed resonators is designed and fabricated to validate the proposed technique. [ABSTRACT FROM AUTHOR]

This paper presents an innovative experimental method for microwave power devices linearity characterization, based on a carefully designed multi-tone signal. Measurements working deeper into the understanding of in-band (IB) signal-to-noise characterization of nonlinear devices are presented. The test signal used in this paper is based on an unequally spaced multi-tone (USMT) signal, which is a tailored stimulus signal with flexible statistics. Its originality stands in its inherent property of allowing signal and intermodulation (IM) distortion separation to facilitate the derivation of the IB signal-to-noise ratio or linearity degradation, without assuming any specific modulation format. For the first time, this paper reports measurements with small $\Delta _{f}$ frequency arrangement using an USMT signal to investigate low frequencies (LFs) parasitic effect on the current and the linearity. Furthermore, this test bench allows to analyze together LF phenomena (“trapping effect”, memory effect, etc.) and high-frequency phenomena under large-signal condition with a telecom like signal. Smith chart load–pull linearity contours under wideband USMT test signals are reported for the first time. This provides a new tool to check system-level design specifications and to optimize radio frequency (RF) power amplifier structures with modulated signals. The measurements were performed using a GaN high-electron-mobility transistors (HEMT) 3-W transistor. [ABSTRACT FROM AUTHOR]

A concept of seamlessly colocated and cointegrated antennas and front-end chain circuits in the form of a unified and integrated design space is proposed, studied, and demonstrated in this paper, which strives to create future joint circuiting-radiating front-end analog functional blocks. To show the proposed concept, the building elements involving dual-function amplifier antenna are highlighted as an example and arranged in a series-connected array, each acting simultaneously as a matching circuit and transmitting antenna. In other words, a single geometrical space serves as both circuits and antennas, meaning a space overlap in which the circuit is an antenna and the antenna is a circuit. This reflects both the harmony and harmonious relationship of the circuit antenna. In this paper, the spacing between two neighboring array elements is utilized to accommodate active devices, such as transistors, in this example. As the first theoretical and experimental demonstration, this paper involves the design of patch antennas, the analysis of mutual coupling, and the placement of amplifying transistors in different operation modes. The modeling procedure for a $1 \times N$ amplifier-antenna system is presented. The proposed concept is experimentally validated by prototyping a $1 \times 2$ amplifier-antenna array at 5 GHz with rectangular patches and off-the-shell HJ-FET. An equivalent circuit network is established for the proposed dual function block. Measured results show that the experimental block has −10 dB matching bandwidth of 125 MHz at the steering angle of +30° with an amplifying gain of 11.5 dB. It is also experimentally illustrated that frequency tuning and beam steering can easily be enabled by varying the dc bias. The design of $1 \times 4$ amplifier-antenna array at 5 GHz is also discussed to generalize the proposed theory and guide the design of higher order amplifier arrays. [ABSTRACT FROM AUTHOR]

Multiarm slotline stubs have been used to increase the bandwidth of slotline open circuits in transitions between microstrip and slotline and between coplanar waveguide and slotline. The model used in prior papers is a series connection of the short-circuit terminated stubs, resulting in an increase in the input impedance by a factor of $N$ , where $N$ is the number of stubs. In this paper, it is shown that this model cannot be applied for slotline with finite width metal planes or coplanar stripline (CPS), because it does not account for higher order modes that are necessarily excited on the multiarm structure. This paper presents a physical explanation and model that accounts for the higher order modes on the structure and explains how the multiarm finite width slotline/CPS stub structure increases the bandwidth of the transitions between slotline and other transmission lines. With the correct model presented in this paper, it is expected that improved slotline or CPS circuits can be developed. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

In the last 10 or 15 years, exciting new developments have occurred in the field of filters and multiplexers. The two words that best explain this phenomenon are “topology” and “technology.” Thus, this paper will cover new connections, new materials, and new processes. This paper summarizes what is new, describes the new devices, and avoids simply surveying the entire field. It is not possible to cover everything, and regrettably, some new and possibly exciting areas are omitted (such as filters fabricated using liquid crystal polymers, active element inclusion, extreme power devices used in accelerators), and others,\ldots, because something has to be left for the next paper! The paper does cover bandstop filters, intrinsically switched film bulk acoustic resonator, and barium–strontium–titanate filters, brand new derivations of lossy filter synthesis and dual-band filter synthesis, multimode networks, new work on optimal multiplexer (multiport network) configurations, and substrate integrated waveguide filters. In each of these areas significant new work has been recently performed and is presented in a summary format suitable for those thinking that the area of filters and multiplexers has become mature (stagnant) with nothing interesting to learn. Nothing could be further from the truth! [ABSTRACT FROM PUBLISHER]

This Transactions’ Mini-Special Issue includes four papers from the 2018 IEEE Radio and Wireless Week (RWW 2018) held in Anaheim (Garden Grove), CA, USA, January 14–17, 2018. RWW consists of five conferences focusing on the wireless communication theory, systems, circuits, and device technologies. They include the Radio and Wireless Symposium, Topical Conference on Power Amplifiers for Wireless and Radio Applications, Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems, Topical Conference on Wireless Sensors and Sensor Networks, and Topical Workshop on The Internet of Space. The program included parallel track technical sessions, three workshops, an Internet of Things (IoT) summit, a plenary session on IoT within 4G/5G networks, a panel session on the role of the device in power amplifier design, a joint RWW student paper contest, and a demo track session. A total of 243 papers were submitted to the RWW 2018 Technical Program Committee and 177 papers were accepted for presentation at the meeting and publication on the IEEE Xplore website. [ABSTRACT FROM AUTHOR]

This paper is aimed to compare the performance of toroidal inductors and planar spiral inductors in multilayered technologies, in terms of achievable inductance density. The optimization of planar toroidal inductors in multilayered substrates is investigated theoretically, and closed formulae are derived for their inductances as a function of geometrical parameters. The obtained model is validated by experimental results and electromagnetic simulation. From the comparison of the inductance of toroidal inductors and compact spiral inductors, a selection rule is proposed to choose the most suitable topology that leads to the most compact design. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

This Special Issue of IEEE Transactions on Microwave Theory and Techniques (TMTT) is comprised of the expanded papers from the 2021 IEEE Microwave Theory and Techniques Society (IEEE MTT-S) International Microwave Symposium (IMS2021), held in Atlanta, GA, USA, on June 2021. The IEEE MTT-S International Microwave Symposium is the world’s major event of microwave technologies annually organized by the IEEE MTT-S as the society’s premier flagship conference. The conference represents a unique opportunity to bring together researchers and practitioners with diverse technical backgrounds to share the most recent advances in MHz-to-THz technologies and systems. Due to the unprecedented pandemic situations, the IMS2021 was held in a hybrid format, comprised of in-person and virtual participation options. The in-person event was held on June 7–10, 2021, at the Georgia World Congress Center, Atlanta. A virtual event followed on June 20–25, 2021. [ABSTRACT FROM AUTHOR]

This paper presents a broadband poly-harmonic behavioral model for microwave mixers operating in the linear regime. It is extracted from large-signal vector measurements and predicts the response with respect to an arbitrary local oscillator (LO) phase. The model is capable of estimating the performance of the converted signals and the main mixing products for an intermediate frequency that spans within an a priori defined bandwidth. This paper gives a detailed model analytical treatment along with a discussion of its properties and the description of the characterization method. The model validation is achieved by the characterization of a subharmonic mixer implemented in the hybrid technology that operates with a 2.229-GHz LO, an intermediate frequency bandwidth of 732–754 MHz, and a corresponding radio frequency bandwidth of 5.191–5.211 GHz. Independent experimental validation is achieved by an image rejection mixer composed of two nominally identical mixers, individually characterized by the proposed technique. Validation is concluded with experimental data, demonstrating the model’s capability to deal with a phase-modulated LO signal. [ABSTRACT FROM PUBLISHER]

Self-tracking receivers have been suggested for satellite and mobile communication applications. In this paper, we propose and demonstrate an array receiver (Rx) architecture based on phase-locked loops. The system is capable of automatically tracking a moving source and providing direction-of-arrival (DOA) estimates calculated from array signal phase differences. After deriving the system transfer functions, we show a digital implementation of the receiver and experimentally prove its phase detection capability. In combination with an eight-element linear array and analog front ends, we build a hybrid receiver and demonstrate its DOA estimation performance in static and dynamic outdoor setups. This paper gives the details about theoretic principles, implementation concept, and realization of the proposed receiver. We demonstrate DOA errors below 4° and show the reproducibility of the results. Using dynamic experiments, we verify the tracking ability of the system, which makes it applicable to retrodirective antennas. [ABSTRACT FROM PUBLISHER]

This paper addresses the estimation and compensation of I/Q imbalance, one of the most prominent impairments found in wideband zero-intermediate frequency transceivers (TRxs). The I/Q imbalance encountered in this kind of TRx comprises not only frequency-selective gain and phase imbalance but also delay imbalance. Unless appropriate compensation is applied, the I/Q imbalance significantly degrades the performance of a communication system. This paper presents a novel compensation technique for transmitter I/Q imbalance based on built-in-self-calibration, a low cost and robust compensation technique that enables manufacturing as well as in-field calibration with low computational complexity. The method's performance is evaluated in a TRx with 64-quadratic-amplitude modulation and 2 GHz of bandwidth implemented with real hardware. The measurements show that the proposed technique achieves an image rejection ratio greater than 35 dB in the entire 2 GHz bandwidth and an error vector magnitude lower than 3%. [ABSTRACT FROM AUTHOR]

The article presents information related to paper submission, submission format, and open access for the author of the periodical.

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

An editorial is presented which offers information for Authors for submission of articles in the journal.

The article focuses on that part of engineering and theory associated with microwave/millimeterwave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals. This includes scientific, technical, and industrial, activities.

This Mini-Special Issue of the IEEE Transactions on Microwave Theory and Techniques includes five expanded papers from the IEEE International Conference on Numerical Electromagnetic Modeling and Optimization for RF, microwave, and terahertz applications (NEMO), held in Beijing, China, July 27–29, 2016. [ABSTRACT FROM PUBLISHER]

This paper presents an integral-equation formulation specialized for the analysis of capacitive waveguide circuits, which include arbitrarily shaped conducting and homogeneous magnetic/dielectric objects. The technique benefits from the symmetry of the structure by formulating a 2-D scattering problem with oblique angle of incidence, combined with the use of the parallel-plate Green’s functions. As practical applications, the paper proposes novel low-pass filter designs loaded or coated with dielectric and magnetic homogeneous materials. If the filter is properly designed, the use of these materials could improve the filter response, selectivity, or out-of-band performance, and power-handling capabilities. Some novel filter design implementations, showing these kinds of benefits, are presented for the first time in this paper. For validation, a commercial full-wave simulator is employed, showing the validity, accuracy, and computational efficiency of the novel software tool. [ABSTRACT FROM PUBLISHER]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

These instructions give guidelines for preparing papers for this publication. Presents information for authors publishing in this journal. [ABSTRACT FROM AUTHOR]

This paper provides theoretical and experimental evidence that, contrary to what is a widely reported belief, the capture time constant of GaN high-electron-mobility transistor (HEMTs) deep-level traps is not infinitesimally shorter than the modulation envelope time features of usual excitation signals. Instead, it can have a nonnegligible impact on their power amplification. A specifically conceived test bench, capable of measuring capture time constants at guaranteed invariant thermal dissipation conditions, revealed that the capture process can range from less than a microsecond up to a few tens of milliseconds. Furthermore, a theoretical justification based on the Shockley–Read–Hall statistics is provided to explain this widespread time constants’ behavior of deep-level traps. As a practical application example of these findings, the detailed characterization of the capture time constants performed in this paper proved to constitute a valuable tool in understanding the behavior of GaN power amplifiers (PAs) designed for pulsed radar signals. [ABSTRACT FROM AUTHOR]

Time reversal (TR) relies on the reciprocity nature of the wave equation. Waves diverging away from a source can be time reversed and back-propagated to focus back at the source. The transmitting and receiving antenna arrays utilized for TR are collectively termed as the TR mirror (TRM). TR imaging in the microwave regime has shown its promise in nondestructive inspection and target localization. This paper deals with the design of a microwave TRM for the detection of breast tumors. The first part of this paper discusses TR simulations based on a signal processing algorithm, to obtain the tumor location from the total fields. The processed time-reversed fields can be back-propagated in a numerical model to focus the wave at the tumor locations. Simulation results aid in investigating the feasibility and the robustness of the method. The second part of this paper deals with experimental studies for the breast tumor detection, using a pulsed time-domain system and the back-propagation model. The successful detection of single and multiple tumors embedded in a liquid breast tissue-based phantom is shown using the microwave system. [ABSTRACT FROM AUTHOR]

This paper presents a seven-port modulator capable of switching the polarization state of the transmitting signal. Similar to the six-port modulator, the proposed device modulates the carrier signal through the reflection coefficients generated by four variable loads. The additional seventh port allows feeding two antennas or a dual-port antenna. The loads control both the complex envelope and the polarization of the transmitted carrier signal. The mathematical model of the device, developed in this paper, is applied to analyze its performance and different modes of operation. For validation, a prototype is manufactured for a center frequency of 1575.42 MHz. It is used to generate M-quadratic-amplitude modulation at different polarizations. The signals recorded at the output of the prototype show good agreement with the values predicted by the model. [ABSTRACT FROM AUTHOR]

This paper presents a new bandwidth tuning theory for Butterworth-response resonator filters. The presented theory shows that the bandwidth of odd-order Butterworth filters can be varied by adjusting only two interresonator coupling structures while maintaining a perfect impedance matching at the center frequency. In other words, this paper presents an analytic approach to reduce the number of tunable coupling structures when designing a bandwidth-tunable resonator filter. Theories for third- and fifth-order direct-coupled filters are discussed in detail, and it is shown that only two interresonator coupling structures are required to be tunable. In addition, for verifying the new bandwidth tuning method, a fifth-order cylindrical cavity filter has been designed, fabricated, and measured. The fabricated filter has an 11:1 bandwidth tuning range. [ABSTRACT FROM AUTHOR]

This paper proposed a method of synthesizing absorptive common-mode filters (A-CMFs) analytically with high absorption efficiency and two designable absorption bands. The proposed method is carried out by a novel circuit architecture and its analysis procedure. In differential mode, the integrity of the differential signals is maintained, and in common mode (CM), two absorption frequency bands can be obtained theoretically. These bands are designable with the analytical equations derived in this paper, so a dual-band or broadband A-CMF design can be easily synthesized by our proposed method. The authors also show that this method can make any one of R-CMFs “upgrade” to an A-CMF by simply adding an additional circuit, and this might be a revolutionary progress for the currently used CM-suppression techniques. To make the proposed concept more understandable, an example is used to demonstrate how the synthesizing methodology works, where a broadband A-CMF with its absorption bands located at 2.4 and 3.6 GHz is designed and implemented. Furthermore, a test sample of this A-CMF is fabricated on a four-layer printed circuit board. It is measured on a probing station, and the measured results are very similar to the simulated results. Finally, a comparison table of all the related works is given, showing that this proposed method really makes a significant improvement for A-CMF techniques. It is worth noting that this circuit design can provide a broadest 95%-absorption band to our best knowledge. [ABSTRACT FROM AUTHOR]

This paper presents a set of wideband, fully integrated E-band power amplifiers (PAs) designed in 0.12- $\mu \text{m}$ silicon-germanium (SiGe) BiCMOS and working in the range of 60–75 GHz. The single PA is based on common-emitter (CE) driver stages followed by a CE output stage. A three-stage and four-stage versions of the single-PA as well as four- and eight-way combined variants of the four-stage PA are measured and compared. The single, four-way, and eight-way combined PAs achieve saturated output powers of 16, 19.5, and 24 dBm with peak power-added efficiencies (PAEs) of 18%, 11%, and 12%, respectively. Modulated waveforms are passed through each amplifier and data rates as high as 32 Gb/s are demonstrated for all amplifiers when driven in the linear mode. Measurements of how error-vector magnitude (EVM) and PAE degrade versus output power are presented and it is demonstrated that the eight-way combined PA can deliver 17–20 dBm of average power in a 64-quadratic-amplitude modulation, 1-Gbaud waveform (6 Gb/s), with an EVM of −32 to −24 dB and a PAE of 3%–5% without predistortion. To the author’s knowledge, this is the first paper reporting detailed measurements of PA EVM and PAE versus output power at these frequencies. [ABSTRACT FROM AUTHOR]

This paper proposes a new design methodology of dual-band stripline circulator for wireless communications applications. As far as the monoband classic circulator is based on coupling the counter-rotating fundamental modes, the operating principle of dual-band phenomenon is based on studying both fundamental and upper resonant modes within ferrite disks. Electromagnetic (EM) simulations have shown that two categories of dual-band operation could be obtained: simple (unidirectional) and left-handed /right-handed (LH–RH) circulators. The application dedicated to these two original concepts will be discussed, and simulation results will be ensured by the measurement of two prototypes in order to validate the methodology’s reliability. [ABSTRACT FROM AUTHOR]

This paper presents a novel quarter-mode packaged bandpass filter with four transmission zeros (TZs) in substrate-integrated waveguide (SIW) technology. The filter has an insertion loss of 2.85 dB at 30 GHz and fractional bandwidth of 20%. The design methodology of the TZs was first demonstrated to increase the attenuations of the filter stopband. The quarter-mode SIW resonators were analyzed with high-mode suppression by properly setting their feed points. The packaged filter was consistent between the simulation and measurement results and offers the advantages of compact configuration and easy integration with other devices. Mode suppressions of up to 110 GHz were also provided. The proposed concept is attractive for designing miniaturized and high-performance-packaged filters for 3-D millimeter-wave transceiver systems. [ABSTRACT FROM AUTHOR]

For heterojunction bipolar transistors (HBTs), the noise correlation influences the noise parameters and is therefore relevant for transistor modeling, especially at sufficiently high frequencies. In order to predict the noise correlation, it is necessary to determine the noise transit time in the noise transport model. In this paper, the noise correlation and noise transit time are predicted from the high current model without measured noise data. The four noise parameters are calculated based on the predicted noise transit time and the Y-parameter noise calculation methodology. The extracted noise transit time is validated by the measured result over bias and temperature, which is determined by fitting NFmin of the silicon-germanium (SiGe) HBT between Y-parameter noise calculation methodology and tuner-based noise measurement. It was found that the noise transit time is independent of frequency but dependent on bias and temperature. Also, the results indicate that the calculated four noise parameters based on the extracted noise transit time have a good agreement with the tuner-based noise measurement. [ABSTRACT FROM AUTHOR]

This paper addresses the mechanisms of wideband power amplifiers’ efficiency degradation in comparison with their narrowband operation. It starts by identifying some possible causes for this performance degradation, showing that the baseband terminations are dominant. A detailed explanation for the efficiency degradation is then presented, considering the scenarios where the most important baseband components fall before or after the resonance imposed by the bias and matching networks. A theoretical model that is able to describe this performance degradation is also presented. Finally, the proposed theory is validated through two implemented power amplifiers with the same fundamental and harmonic terminations, but with different baseband networks, showing that an optimized bias network design can improve the efficiency performance of a PA. [ABSTRACT FROM AUTHOR]

An intrinsically switchable and frequency reconfigurable bulk acoustic wave filter bank based on ferroelectric barium strontium titanate (BST) is presented. Ferroelectric BST possesses electric-field-induced piezoelectricity, enabling the design of voltage-controlled acoustic devices, including thin-film bulk acoustic resonators and solidly mounted resonators. In this paper, a triple-band switchable filter bank, consisting of three 2.5-stage filters based on BST FBARs, is designed, simulated, and fabricated for the first time. The bandpass filters have center frequencies at 1.85, 1.96, and 2.04 GHz and are selectively turned on based upon the external dc bias voltage applied to each filter. Turning off all the filters provide an isolation of more than 27 dB between the input and output ports. The presented intrinsically switchable ferroelectric filter bank potentially simplifies future radio frequency front ends by integrating both switching and filtering functionalities onto a single device and reduces the overall circuit area. [ABSTRACT FROM AUTHOR]

Nonlinear transmission lines (NLTLs) are passive networks with the capability of modulating baseband pulses. These networks are used for generating RF pulses at high-power levels. NLTLs have a unique performance in high-power RF pulse generation among all the generators based on the solid-state technology. A high-power rectangular pulse is injected to the line, gradually evolved into an oscillatory pulse while propagating through the network, and finally, in the form of a high-power RF pulse, is delivered to the load. Properly terminating an NLTL, in order to transfer the maximum available RF power to the load, is an important problem. In this paper, an accurate analysis is presented, which gives a closed-form formula for the output RF power in lossy NLTLs. Using this analysis, optimal resistive terminating load for RF applications of NLTLs is extracted. The output central frequency is also investigated in this paper. All the obtained theoretical results are verified by SPICE simulations and measurements in two implemented NLTLs. [ABSTRACT FROM AUTHOR]

This Mini-Special Issue of the IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES (TMTT) is devoted to the 2019 Asia-Pacific Microwave Conference (APMC 2019), Singapore, December 10–13, 2019. APMC is one of the premier international conferences in the microwave community. The conference brought in a unique mix of high-quality keynote, invited, and contributed papers by world-class speakers from academia and industry, providing an opportunity for microwave family members to exchange their visions, insights, challenges, and progress in microwaves. It received a total submission of 1064 papers covering microwave to terahertz spectrum with a variety of applications by the authors from 56 countries/regions and finally accepted 720 papers after careful and rigorous peer review. The conference consisted of 71 technical oral and poster sessions from 53 technical tracks, eight workshops/short courses, 29 invited talks, and two plenary talks. In particular, 17 special sessions are convened by session organizers to discuss emerging technologies. [ABSTRACT FROM AUTHOR]

The article reports that the IEEE Transactions on microwave theory and techniques focuses on that part of engineering and theory associated with microwave/millimeterwave components, devices, circuits, and systems involving the generation, modulation, demodulation, control, transmission, and detection of microwave signals.

This paper presents a new spiral inductor based on substrate integrated suspended line (SISL) technology. SISL is a new type of transmission line, which has many merits, such as low loss, low dispersion, and self-packaging. New series of spiral inductors based on this advanced SISL platform is proposed and modeled in this paper. SISL to microstrip transition is designed for the measurement of the SISL inductor, and an open-short deembedding method is introduced for the accurate extraction of inductor network parameters. A $\pi$ equivalent circuit model is applied for modeling of the SISL inductor and new double-sided SISL (DSISL) inductor, and the accurate empirical expression of inductance L$ , peak quality factor Q_{\mathrm {max}} , and self-resonance frequency are given. The typical relative error of each expression is less than 8%. Finally, a new DSISL inductor with patterned substrate is proposed, which can significantly improve the quality factor up to 40%. Simulation and measurement results show good agreement. [ABSTRACT FROM PUBLISHER]