Development of planar filters and diplexers for wireless transceiver front ends

The central theme of this work is the design of compact microstrip bandpass filters and diplexers and the investigation of applications of these circuits in integrated transceiver RF front-end. The core of this thesis therefore presents the following stages of the work: - Analysis of coupled pseudo-interdigital resonators and lines; formulation of approximate transmission zero conditions and the investigation of coupling between these two resonators and related structures. - Development of compact, low loss and high selectivity microstrip pseudointerdigital bandpass filters. The design procedure of the filter consists of three simple steps, starting from the design of a parallel-coupled bandpass filter using the image parameter method applied to coupled microstrip lines. The development of compact microstrip diplexers composed of these filters uses the optimized common-transformer diplexing technique. An experimental verification of the developed filters and diplexers is made. - Investigation of the use of stepped impedance resonators (SIR) for the design of pseudo-interdigital bandpass filters with advanced characteristics. The design of compact dual-band filter using SIR. The investigation of possible improvement of the stopband of bandpass filters using bandstop generating structures. The application of SIR, defected ground structures (DGS), spur-lines, and opencircuited stubs in the design of compact bandpass filters with improved stopband. - The application of the proposed filters and diplexers in the design of integrated antenna filters and antenna diplexers. Improvement of performance of patch antennas, such as suppression of spurious harmonics of single-band antenna and improvement of bandwidth and selectivity of dual-band antenna, as a result of integration with filters. Separation of antennas’ bands and reduction of component count in integrated antenna diplexer

Balanced quasi-elliptic-type combline diplexer with multiextracted-pole junction/output sections

A class of coupled-multiline quasi-elliptic-type balanced diplexer device with closely spaced channels and its balanced coupling-routing-diagram formalism to simultaneously model its differential- and common-mode operation are reported. It employs third-order combline-type bandpass filters (BPFs) in its filtering channels, whose resonating lines are connected at one of their extremes to the symmetry plane of the balanced-circuit structure (i.e., virtual grounds for the differential mode), along with a multiextracted-pole/coupled-multiline dual-band BPF junction and single-band BPF output cells. In differential-mode operation, the dual-band BPF junction adds one in-band pole to each diplexer channel and three transmission zeros (TZs) to both channels, whereas the single-band BPF output cells incorporate one in-band pole and two TZs in their corresponding channels. In this manner, increased-selectivity differential-mode BPF transfer functions for the diplexer channels when compared to those of its third-order combline-type BPFs are obtained. Grounded resistors are connected at the symmetry plane of the balanced diplexer for all the resonating lines of the combline-type BPFs, which become detuned with regard to the poles associated with the dual-band BPF junction and the single-band BPF output cells under common-mode excitation. This allows for high common-mode suppression levels in wide spectral ranges to be realized for both channels while maintaining the same TZs as in differential-mode operation. For practical-validation purposes, a 1.6-GHz/1.8-GHz microstrip prototype is manufactured and tested.Ministerio de Economía, Industria y CompetitividadEuropean Commissio

A Combined 90/900 MHz IC Architecture for Smart Tag Application

In this work we present a combined 90/900 MHz Energy Harvesting Architecture for active smart tag Application. The harvester takes advantages from a dedicated diplexer and a power manager for battery life enhancement purposes. The system has been optimized in the 900 MHz frequency range by analyzing a probabilistic approach used for modeling the possible amount of Global System for Mobile communication (GSM) energy that could be harvested while a fixed power downlink scenario has been adopted for the 90MHz band. A preliminary IC system with a 0.18μm CMOS SMIC technology has been designed and optimized at 90 and 900 MHz while discrete element board, to be integrated with the proposed IC, with commercial components has been developed and tested. Concerning simulation results on the IC design they have confirmed that the integrated system handles an incoming power typically ranging from -25 dBm to 5 dBm by rectifying the variable input signals into a DC voltage source with an average 50% efficiency

Advanced Techniques for the Characterization and Experimental Validation of Passive Inter-Modulation Effect (PIM) in Space Communications Systems

[ES] Los satélites de telecomunicación operan en entornos multiportadora, bajo una demanda continua de mayores capacidades de transmisión. Esto ha originado un aumento en los niveles de potencia de RF, frecuencias de trabajo, y número de canales transmitidos, estimulando la aparición de efectos no lineales de alta potencia, como Multipactor, Corona, y la Intermodulación Pasiva (PIM). Entre los efectos anteriores, el PIM es el menos comprendido, debido a su carácter no lineal y su estrecha relación con la fabricación, lo que dificulta el desarrollo de modelos fiables. Los términos de PIM generados en el enlace descendente pueden interferir a la débil señal en el canal de recepción, amenazando la capacidad de recepción del enlace ascendente. Los modelos tradicionales de PIM suelen basarse en una excitación formada por dos portadoras. Aunque se trata de un caso simple y bastante representativo, presenta diferencias importantes con el escenario real multiportadora. El trabajo de este Ph.D. intenta reducir estas diferencias. Para lograrlo, se realizan dos nuevas contribuciones de relevancia para las condiciones reales de operación de los satélites. En concreto, se ha investigado de forma teórica el rol de las fases de las portadoras en el PIM, y se ha propuesto un nuevo modelo que tiene en cuenta el efecto de las portadoras no contribuyentes en un cierto término de PIM, aplicando un nuevo principio de conservación de energía. Los resultados obtenidos con ambos modelos teóricos se ajustan a los datos experimentales. Debido a la compleja naturaleza del PIM, la validación de los componentes de RF de satélites se realiza mediante tests. Por lo tanto, la disponibilidad de bancos de medida de PIM es un tema de interés para la industria espacial. Sin embargo, el diseño de bancos de altas prestaciones es un desafío, ya que su nivel de PIM debe ser inferior al requerido para validar los dispositivos. Para hardware de satélites, la diferencia entre el nivel de las portadoras a transmitir y la señal de RF a detectar es como 185 dBc. En este Ph.D. se proponen unas nuevas arquitecturas integradas de bancos de PIM en guía de ondas, que cubren tanto el PIM conducido como el radiado. Dichas arquitecturas permiten una reducción importante del nivel de PIM residual del sistema de medida, siendo flexibles, capaces de manejar elevados niveles de potencia, y libres de resonancias e interacciones indeseadas. Los elementos claves de estos bancos son unos multiplexores de bajo PIM, que pueden incorporar dos familias de filtros que admiten un elevado número de ceros de transmisión, y por tanto, son capaces de proporcionar un elevado rechazo en la banda de recepción del PIM. Los bancos de medida de PIM conducido por onda reflejada, sin embargo, están expuestos al PIM generado por la carga empleada para absorber las portadoras de alta potencia. Para resolver esta situación, se han propuesto unas nuevas cargas de bajo PIM, que reducen el PIM residual de estos sistemas de medida. Así mismo, se ha elaborado un nuevo tipo de transición para mitigar el PIM respecto a flanges estándar. Para escenarios radiados se ha desarrollado una formulación capaz de relacionar densidades de potencia en el dispositivo bajo test con los niveles detectados en el banco de medida, y que por tanto permiten trasladar especificaciones de PIM del satélite al sistema de medida. Por último, se han mostrado varias campañas de medida de PIM realizadas con bancos implementados acorde a las nuevas arquitecturas propuestas. Las medidas cubren varias bandas de frecuencia y diferentes escenarios (tanto PIM conducido como radiado). Se ha determinado el excepcional nivel de fondo de ruido de PIM logrado en cada banco. Además, se han mostrado resultados obtenidos para medidas de PIM radiado en capas aislantes multicapa y mallas reflectoras, obteniendo interesantes conclusiones en cuanto a geometrías y impacto que tienen en el PIM elementos como los bordes serrados y los remaches.[CA] Els satèl·lits de telecomunicació operen en entorns multiportadora, sota una demanda contínua de majors capacitats de transmissió. Això ha originat un augment en els nivells de potència de *RF, freqüències de treball, i nombre de canals transmesos, estimulant l'aparició d'efectes no lineals d'alta potència, com *Multipactor, Corona, i la Intermodulació Passiva (*PIM). Entre els efectes anteriors, el *PIM és el menys comprés, a causa del seu caràcter no lineal i la seua estreta relació amb la fabricació, la qual cosa dificulta el desenvolupament de models fiables. Els termes de *PIM generats en l'enllaç descendent poden interferir al feble senyal en el canal de recepció, amenaçant la capacitat de recepció de l'enllaç ascendent. Els models tradicionals de *PIM solen basar-se en una excitació formada per dues portadores. Encara que es tracta d'un cas simple i bastant representatiu, presenta diferències importants amb l'escenari real multiportadora. El treball d'aquest *Ph.D. intenta reduir aquestes diferències. Per a aconseguir-ho, es realitzen dues noves contribucions de rellevància per a les condicions reals d'operació dels satèl·lits . En concret, s'ha investigat de manera teòrica el rol de les fases de les portadores en el *PIM, i s'ha proposat un nou model que té en compte l'efecte de les portadores no contribuents en un cert terme de *PIM, aplicant un nou principi de conservació d'energia. Els resultats obtinguts amb tots dos models teòrics s'ajusten a les dades experimentals. A causa de la complexa naturalesa del *PIM, la validació dels components de *RF de satèl·lits es realitza mitjançant tests. Per tant, la disponibilitat de bancs de mesura de *PIM és un tema d'interés per a la indústria espacial. No obstant això, el disseny de bancs d'altes prestacions és un desafiament, ja que el seu nivell de *PIM ha de ser inferior al requerit per a validar els dispositius. Per a maquinari de satèl·lits , la diferència entre el nivell de les portadores a transmetre i el senyal de *RF a detectar és com 185 *dBc. En aquest *Ph.D. es proposen unes noves arquitectures integrades de bancs de *PIM en guia d'ones, que cobreixen tant el *PIM conduït com el radiat. Aquestes arquitectures permeten una reducció important del nivell de *PIM residual del sistema de mesura, sent flexibles, capaces de manejar elevats nivells de potència, i lliures de ressonàncies i interaccions indesitjades. Els elements claus d'aquests bancs són uns multiplexors de baix *PIM, que poden incorporar dues famílies de filtres que admeten un elevat nombre de zeros de transmissió, i per tant, són capaces de proporcionar un elevat rebuig en la banda de recepció del *PIM. Els bancs de mesura de *PIM conduït per ona reflectida, no obstant això, estan exposats al *PIM generat per la càrrega emprada per a absorbir les portadores d'alta potència. Per a resoldre aquesta situació, s'han proposat unes noves càrregues de baix *PIM, que redueixen el *PIM residual d'aquests sistemes de mesura. Així mateix, s'ha elaborat un nou tipus de transició per a mitigar el *PIM respecte a *flanges estàndard. Per a escenaris radiats s'ha desenvolupat una formulació capaç de relacionar densitats de potència en el dispositiu sota test amb els nivells detectats en el banc de mesura, i que per tant permeten traslladar especificacions de *PIM del satèl·lit al sistema de mesura. Finalment, s'han mostrat diverses campanyes de mesura de *PIM realitzades amb bancs implementats concorde a les noves arquitectures proposades. Les mesures cobreixen diverses bandes de freqüència i diferents escenaris (tant *PIM conduït com radiat). S'ha determinat l'excepcional nivell de fons de soroll de *PIM reeixit en cada banc. A més, s'han mostrat resultats obtinguts per a mesures de *PIM radiat en capes aïllants multicapa i malles reflectores, obtenint interessants conclusions quant a geometries i impacte que tenen en el *PIM elements com les vores serrades i els reblons.[EN] Modern satellite payloads operate in multicarrier scenarios, under a continuous demand for higher capacity links. This leads to an increase in the RF power levels, frequency of operation, and the number of transmitted channels, thus stimulating non-linear high-power effects, such as Multipactor, Corona, thermal issues and Passive Inter-Modulation (PIM). Among the above-mentioned phenomena, PIM is the less studied, or, at least, understood. This is due to its extreme non-linear nature and its close relation to workmanship, which make very difficult the development of models able to faithfully predict and explain PIM degradation. PIM terms, once ignited in the downlink, may interfere the weak signal to be detected in the uplink channel, thus threatening the payload throughput. Traditional PIM models are based on a two-carriers excitation. This is a simple and quite representative case, but has significant differences with the real multi- carrier scenario. This Ph.D. thesis work tries to diminish this gap by two novel contributions of relevance for real operation conditions. Firstly, the role of the carrier phases (neglected for two-carriers excitation) has been theoretically investigated. Secondly, a new model to account for the effect of non-contributing carriers for a given PIM term has been developed, which is based on a novel energy conservation assumption. The resulting models fit to experimental data. Due to the complexity of PIM modeling, PIM validation of RF components is conducted only by testing. The availability of low PIM test set-ups is therefore of great interest for the space industry. However, the design of low PIM test benches is challenging, as their intrinsic residual PIM has to be below the one requested to validate the test devices. For satellite hardware, the dynamic range between the RF power levels of the transmission carriers and the signal to be detected may be 185 dBc. During this Ph.D. thesis work, novel integrated test bed architectures in waveguide technology, both for conducted and radiated PIM scenarios, have been developed. These architectures consent a mitigation of the residual PIM of the test facility, being at the same time flexible, free from unwanted interactions and spurious resonances, and able to withstand considerable RF power levels for the transmission carriers. The key elements of these set-ups are the low PIM multiplexers, which may integrate two new families of waveguide filters able to provide a high number of transmission zeros, and therefore a high rejection, in the PIM reception channel. The test benches conceived for measuring conducted backward PIM, however, are normally unprotected from the PIM generated by the termination absorbing the high-power transmission carriers. To alleviate this situation, a new type of low PIM terminations in waveguide technology has been proposed and verified with PIM tests, showing a clear benefit in mitigating the residual PIM of the test facilities. Moreover, novel transitions able to improve the PIM performance of standard flanges have also been conceived. Finally, and with regard to radiated scenarios, a novel formulation able to convert payload PIM specifications to a practical PIM test is proposed. This formulation consents to link the power flux densities at the device under test (DUT) with the RF power levels measured by the test bench. Last, a large class of PIM measurements carried out with the novel test bed architectures have been reported. These measurements cover several frequency bands (C-, Ku-, K- and Ka) and different PIM scenarios, both conducted and radiated. The exceptional residual PIM noise floor of each test bed will be pointed out. In addition, PIM tests on an anechoic chamber facility, multi-layer insulation blankets (MLIs) and reflector mesh samples are presented, with interesting considerations about the geometry of the structure and the impact on the PIM performance of typical elements as sawing areas and rivets.Smacchia, D. (2022). Advanced Techniques for the Characterization and Experimental Validation of Passive Inter-Modulation Effect (PIM) in Space Communications Systems [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/182402TESI

High-Power Microwave/ Radio-Frequency Components, Circuits, and Subsystems for Next-Generation Wireless Radio Front-Ends

As the wireless communication systems evolve toward the future generation, intelligence will be the main signature/trend, well known as the concepts of cognitive and software-defined radios which offer ultimate data transmission speed, spectrum access, and user capacity. During this evolution, the human society may experience another round of `information revolution\u27. However, one of the major bottlenecks of this promotion lies in hardware realization, since all the aforementioned intelligent systems are required to cover a broad frequency range to support multiple communication bands and dissimilar standards. As the essential part of the hardware, power amplifiers (PAs) capable of operating over a wide bandwidth have been identified as the key enabling technology. This dissertation focuses on novel methodologies for designing and realizing broadband high-power PAs, their integration with high-quality-factor (high-Q) tunable filters, and relevant investigations on the reliabilities of these tunable devices. It can be basically divided into three major parts: 1.Broadband High-Efficiency Power Amplifiers. Obtaining high PA efficiency over a wide bandwidth is very challenging, because of the difficulty of performing broadband multi-harmonic matching. However, high efficiency is the critical feature for high-performance PAs due to the ever-increasing demands for environmental friendliness, energy saving, and longer battery life. In this research, novel design methodologies of broad-band highly efficient PAs are proposed, including the first-ever mode-transferring PA theory, novel matching network topology, and wideband reconfigurable PA architecture. These techniques significantly advance the state-of-the-art in terms of bandwidth and efficiency. 2.Co-Design of PAs and High-Q Tunable Filters. When implementing the intelligent communication systems, the conventional approach based on independent RF design philosophy suffers from many inherent defects, since no global optimization is achieved leading to degraded overall performance. An attractive method to solve these difficulties is to co-design critical modules of the transceiver chain. This dissertation presents the first-ever co-design of PAs and tunable filters, in which the redundant inter-module matching is entirely eliminated, leading to minimized size & cost and maximized overall performance. The saved hardware resources can be further transferred to enhance system functionalities. Moreover, we also demonstrate that co-design of PAs and filters can lead to more functionalities/benefits for the wireless systems, e.g. efficient and linear amplification of dual-carrier (or multi-carrier) signals. 3.High-Power/Non-Linear Study on Tunable Devices. High-power limitation/power handling is an everlasting theme of tunable devices, as it determines the operational life and is the threshold for actual industrial applications. Under high-power operation, the high RF voltage can lead to failures like tuners\u27 mechanical deflections and gas discharge in the small air spacing of the cavity. These two mechanisms are studied independently with their instantaneous and long-term effects on the device performance. In addition, an anti-biased topology of electrostatic RF MEMS varactors and tunable filters is proposed and experimentally validated for reducing the non-linear effect induced by bias-noise. These investigations will enlighten the designers on how to avoid and/or minimize the non-ideal effects, eventually leading to longer life cycle and performance sustainability of the tunable devices

Millimeter-Wave Concurrent Dual-Band Sige Bicmos Rfic Phased-Array Transmitter and Components

A concurrent dual-band phased-array transmitter (TX) and its constituent components are studied in this dissertation. The TX and components are designed for the unlicensed bands, 22–29 and 57–64 GHz, using a 0.18-μm BiCMOS technology. Various studies have been done to design the components, which are suitable for the concurrent dual-band phased-array TX. The designed and developed components in this study are an attenuator, switch, phase shifter, power amplifier and power divider. Attenuators play a key role in tailoring main beam and side-lobe patterns in a phased-array TX. To perform the function in the concurrent dual-band phased-array TX, a 22–29 and 57–64 GHz concurrent dual-band attenuator with low phase variations is designed. Signal detection paths are employed at the output of the phased-array TX to monitor the phase and amplitude deviations/errors, which are larger in the high-frequency design. The detected information enables the TX to have an accurate beam tailoring and steering. A 10–67 GHz wide-band attenuator, covering the dual bands, is designed to manipulate the amplitude of the detected signal. New design techniques for an attenuator with a wide attenuation range and improved flatness are proposed. Also, a topology of dual-function circuit, attenuation and switching, is proposed. The switching turns on and off the detection path to minimize the leakages while the path is not used. Switches are used to minimize the number of components in the phased-array transceiver. With the switches, some of the bi-directional components in the transceiver such as an attenuator, phase shifter, filter, and antenna can be shared by the TX and receiver (RX) parts. In this dissertation, a high-isolation switch with a band-pass filtering response is proposed. The band-pass filtering response suppresses the undesired harmonics and intermodulation products of the TX. Phase shifters are used in phased-array TXs to steer the direction of the beam. A 24-GHz phase shifter with low insertion loss variation is designed using a transistor-body-floating technique for our phased-array TX. The low insertion loss variation minimizes the interference in the amplitude control operation (by attenuator or variable gain amplifier) in phased-array systems. BJTs in a BiCMOS process are characterized across dc to 67 GHz. A novel characterization technique, using on-wafer calibration and EM-based de-embedding both, is proposed and its accuracy at high frequencies is verified. The characterized BJT is used in designing the amplifiers in the phased-array TX. A concurrent dual-band power amplifier (PA) centered at 24 and 60 GHz is proposed and designed for the dual-band phased-array TX. Since the PA is operating in the dual frequency bands simultaneously, significant linearity issues occur. To resolve the problems, a study to find significant intermodulation (IM) products, which increase the third intermodulation (IM3) products most, has been done. Also, an advanced simulation and measurement methodology using three fundamental tones is proposed. An 8-way power divider with dual-band frequency response of 22–29 and 57–64 GHz is designed as a constituent component of the phased-array TX

Microwave Metamaterial Applications using Complementary Split Ring Resonators and High Gain Rectifying Reflectarray for Wireless Power Transmission

In the past decade, artificial materials have attracted considerable attention as potential solutions to meet the demands of modern microwave technology for simultaneously achieving component minimization and higher performance in mobile communications, medical, and optoelectronics applications. To realize this potential, more research on metamaterials is needed. In this dissertation, new bandpass filter and diplexer as microwave metamaterial applications have been developed. Unlike the conventional complementary split ring (CSRR) filters, coupled lines are used to provide larger coupling capacitance, resulting in better bandpass characteristics with two CSRRs only. The modified bandpass filters are used to deisgn a compact diplexer. A new CSRR antenna fed by coplanar waveguide has also been developed as another metamaterial application. The rectangular shape CSRRs antenna achieves dual band frequency properties without any special matching network. The higher resonant frequency is dominantly determined by the outer slot ring, while the lower resonant frequency is generated by the coupling between two CSRRs. The proposed antenna achieves about 35 percent size reduction, compared with the conventional slot antennas at the low resonant frequencies. As a future alternative energy solution, space solar power transmission and wireless power transmission have received much attention. The design of efficient rectifying antennas called rectennas is very critical in the wireless power transmission system. The conventional method to obtain long distance range and high output power is to use a large antenna array in rectenna design. However, the use of array antennas has several problems: the relatively high loss of the array feed networks, difficultiy in feeding network design, and antenna radiator coupling that degrades rectenna array performance. In this dissertation, to overcome the above problems, a reflectarray is used to build a rectenna system. The spatial feeding method of the reflectarray eliminates the energy loss and design complexity of a feeding network. A high gain rectifying antenna has been developed and located at the focal point of the reflectarray to receive the reflected RF singals and genterate DC power. The technologies are very useful for high power wireless power transmission applications

Tunable Superconducting Microwave Filters

Adaptive microwave systems can benefit from the use of low loss tunable microwave filters. Realizing these tunable filters that show low loss characteristics can be very challenging. The proper materials, tuning elements, and filter designs need to be considered when creating a low loss tunable filter. The integration of low loss microelectromechanical systems (MEMS) and superconducting circuits is one method of achieving these types of tunable filters. The thesis introduces new multi-layer low temperature superconducting (LTS) filters and diplexers and novel topologies for tunable filters and switched multiplexers. An efficient method of designing such filters is proposed. A fabrication process to monolithically integrate MEMS devices with high temperature superconducting (HTS) circuits is also investigated in this thesis. The reflected group delay method, usually used for filter tuning, is further developed for use in designing microwave filters. It is advantageous in the design of filters to have electromagnetic simulation results that will correlate well to the fabricated microwave filters. A correction factor is presented for use with the reflected group delay method so the group delay needs to be matched to the appropriate value at the center frequency of the filter and be symmetric about the center frequency of the filter. As demonstrated with an ideal lumped element filter, the group delay method can be implemented when a closed form expression for the circuit is not known. An 8-pole HTS filter design and an 8-pole multi-layer LTS filter design demonstrate the use of the reflected group delay method. Low temperature superconducting filters, couplers and diplexers are designed and fabricated using a multilayer niobium fabrication process traditionally used for superconducting digital microelectronics. The feasibility of realizing highly miniaturized microwave niobium devices allows for the integration of superconducting digital microelectronics circuits and analog microwave devices on a single chip. Microwave devices such as bandpass filters, lowpass filters, bandstop filters, quadrature hybrids, and resistive loads are all demonstrated experimentally. New tunable filter designs are presented that can make use of MEMS switches. A manifold-coupled switched multiplexer that allows for 2^N possible states is presented. The tunable multiplexer has N filters connected to two manifolds and has embedded switches, which detune certain resonators within the filters to switch between ON and OFF states for each channel. The new concept is demonstrated with a diplexer design and two 3-pole coplanar filters. The concept is further developed through test results of a fabricated HTS triplexer and electromagnetic simulations to demonstrate a superconducting manifold-coupled switched triplexer. Another filter design is presented that makes use of switches placed only on the resonators of the filters. This filter design has N possible states and the absolute bandwidth can be kept constant for all N states. Finally, the integration of HTS circuits and MEMS devices is investigated to realize low loss tunable microwave filters. The hybrid integration is first performed through the integration of an HTS microstrip filter and commercially available RF MEMS switches. A fabrication process to monolithically integrate MEMS devices and high temperature superconducting circuits is then investigated. The fabrication process includes a titanium tungsten layer, which acts as both a resistive layer and an adhesion for the dielectric layer, an amorphous silicon dielectric layer, a photoresist sacrificial layer, and the top gold layer. The fabrication process is built up on a wafer with a thin film of a high temperature superconducting material covered with a thin film of gold. Several processes are tested to ensure that the superconducting properties of the thin film are not affected during the MEMS fabrication process