Microwave Filters in Planar and Hybrid Technologies with Advanced Responses

[ES] La presente tesis doctoral tiene como principal objetivo el estudio, diseño, desarrollo y fabricación de nuevos dispositivos pasivos de microondas, tales como filtros y multiplexores con respuestas avanzadas para aplicaciones de alto valor añadido (i.e. comerciales, militares, espacio); orientados a distintos servicios, actuales y futuros, en sistemas inalámbricos de comunicación. Además, esta investigación se centrará en el desarrollo de filtros encapsulados de montaje superficial y con un elevado grado de miniaturización. Para ello, se propone investigar distintas técnicas que consigan respuestas muy selectivas o con unas características exigentes en rechazo (mediante la flexible introducción de ceros de transmisión), así como una excelente planaridad en banda (aplicando técnicas tales como la mejora del Q o el diseño de filtros con pérdidas, lossy filters), obteniendo de este modo respuestas mejoradas, con respecto a soluciones conocidas, en los componentes de microondas desarrollados. De forma general, la metodología seguida se iniciará con una búsqueda y conocimiento del estado del arte sobre cada uno de los temas que se acometerán en esta tesis. Tras ello, se establecerá un procedimiento de síntesis que permitirá acometer de forma teórica los objetivos y especificaciones a conseguir en cada caso. Con ello, se establecerán las bases para iniciar el proceso de diseño, incluyendo co-simulación circuital/electromagnética y optimización que permitirán, en última instancia, implementar la solución planteada en cada caso de aplicación concreto. Finalmente, la demostración y validez de todas las investigaciones realizadas se llevará a cabo mediante la fabricación y caracterización experimental de distintos prototipos.[CA] La present tesi doctoral té com a principal objectiu l'estudi, disseny, desenvolupament I fabricació de nous dispositius passius de microones, com ara filtres i multiplexors amb respostes avançades per a aplicacions d'alt valor afegit, (comercials, militars, espai); orientats a oferir diferents serveis, actuals i futurs, en els diferents sistemes sense fils de comunicació. A més, aquesta investigació es centrarà en el desenvolupament de filtres encapsulats de muntatge superficial i amb un elevat grau de miniaturització. Per a això, es proposa investigar diferents tècniques que aconsegueixin respostes molt selectives o amb unes característiques exigents en rebuig (mitjançant la flexible introducció de zeros de transmissió), així com una excel·lent planaritat en banda (aplicant tècniques com ara la millora de l'Q o el disseny de filtres amb perdues, lossy filters), obtenint d'aquesta manera respostes millorades, respecte solucions conegudes, en els components de micrones desenvolupats. De forma general, la metodologia seguida s'iniciarà amb una recerca i coneixement de l'estat de l'art sobre cadascun dels temes que s'escometran en aquesta tesi. Després d'això, s'establirà un procediment de síntesi que permetrà escometre de forma teòrica els objectiusi especificacions a aconseguir en cada cas. Amb això, s'establiran les bases per iniciar el procés de disseny, amb co-simulació circuital / electromagnètica i optimització que permetran, en última instància, implementar la solució plantejada en cada cas d'aplicació concret. Finalment, la demostració i validesa de totes les investigacions realitzades es durà a terme mitjançant la fabricació i caracterització experimental de diferents prototips.[EN] The main objective of this doctoral thesis is the study, design, development and manufacture of new passive microwave components, such as filters and multiplexers with advanced responses for commercials, military and space applications; oriented to other different services, in current and future wireless communication systems. In addition, this research will focus on the development of surface-mounted encapsulated filters with a high degree of miniaturization. With this purpose, it is proposed to investigate different techniques that achieve highly selective responses or with demanding characteristics in rejection (through the flexible introduction of transmission zeros), as well as an excellent in-band planarity (applying techniques such as the Q enhancement or lossy filters), thus obtaining improved responses, with respect to known solutions, in the developed microwave components. In general, the followed methodology will begin with a search and knowledge of the state of the art on each of the topics addressed in this thesis. After that, a synthesis procedure will be established, which will allow the achievement of the objectives and specifications in a theoretical way, for each case. With this, the bases will be established to start the design process, with circuital and electromagnetic co-simulations and optimizations that will allow, ultimately, to implement the proposed solution, in every application case, specifically. Finally, the demonstration and validity of all the investigations will be carried out through the manufacture and experimental characterization of different prototypes.Marín Martínez, S. (2022). Microwave Filters in Planar and Hybrid Technologies with Advanced Responses [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/18894

Dielectric resonator bandstop filters

Dielectric resonators have been widely employed in wireless and satellite communication systems due to their inherently large Q allowing them to fashion low loss and narrow bandwidth filters. Recent progress has adopted these resonators in applications requiring low volume and mass for demanding specifications. The technology at present consists of an assortment of bandpass filters using dielectric resonators but there is little published material on bandstop filters employing such resonators. Bandstop filters are desirable to suppress frequencies at the front end of wireless communication systems. To meet future demands, it is imperative to reduce the costs of these filters in both volume and weight using dielectric resonators. This thesis presents compact mono-mode and dual-mode bandstop dielectric resonator structures. The former consists of a dielectric-loaded waveguide cavity filter that offers a miniaturised version to typical cavity dielectric resonator filters requiring high unloaded Qs. The niono-mode filter described is ideal for relaxed specifications requiring a lower Q resonator to replace common coaxial resonator filters. For applications requiring high bandwidth, this resonator is improved by coupling a dielectric ring resonator to a coaxial transmission line. A novel dual-mode bandstop resonator is developed taking advantage of the geometry of a cylindrical puck within a single shielded cavity to create two degenerate modes with equal resonant frequency, effectively replacing two mono-mode cavities. Miniaturisation is achieved by sitting the dielectric puck at the base of the cavity and correct phase separation between the orthogonal modes is produced from a curved uniform transmission line. The mode behaviour is observed in the physical realisations using a 3D FEM solver. Advanced filtering functions using prescribed reflection zeros is demonstrated with the simulation of a dual-cavity, dual-mode bandstop resonator where inter- and intra- cavity couplings are controlled. The miniaturisation techniques discussed in this thesis will provide cost-reduction for microwave communication systems requiring high- Q bandstop filters.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Development of waveguide filter structures for wireless and satellite communications

This thesis explores the possibilities of the design and realization of compact conventional and substrate integrated waveguide structures with improved performance taking advantage of recent cross-coupled resonator filters theory achievements such as the modular filter design approach using non-resonating nodes and inline extracted pole filters. Therefore, the core of the thesis presents the following stages of work: -- Solution of electromagnetic problem for wave propagation in rectangular waveguide structures; overview of substrate integrated waveguides. -- Review of available design procedures for cross-coupled resonator filters; realization of coupling matrix synthesis methods by optimization. -- Investigation of the possibility to implement filtering modules using E-plane metallo-dielectric inserts in conventional rectangular waveguides. Application of the modules in configurations of bandpass and dual-band filters. Experimental verification of the filters. -- Implementation of inline extracted pole filters using E-plane inserts in rectangular waveguides. Use of generalized coupling coefficients concept for individual or coupled extracted pole sections. Development of new extracted pole sections. Application of the sections in the design of compact cross-coupled filters with improved stopband performance. -- Application of the techniques developed for conventional rectangular waveguides to substrate integrated technology. Development of a new negative coupling structure for folded substrate integrated resonators. Design of improved modular and extracted pole filters using substrate integrated waveguides

Impedance Transformers

Non

Synthesis of Filters for Digital Wireless Communications

Firstly, a new synthesis method for the generation of the generalized Chebyshev characteristic polynomials has been presented. The general characteristic function is generated by a linear combination of Chebyshev basis characteristic functions. The basis functions for different filtering functions may easily be determined based on the number and position of reflection and transmission zeros. These basis functions enable direct synthesis of both lumped and distributed filter networks. Different filter functions including but not limited to low-pass, bandpass and dual bandpass filters, have been synthesised to demonstrate the general application of the synthesis method. Secondly, a new method for the design of a new class of distributed low-pass filter has been presented that enables exact realisation of the series short circuited transmission lines which are normally approximated via unit elements in other filter realisations. The filters are based on parallel coupled high impedance transmission lines which are terminated at one end in open-circuited stubs. The approach enables realisation of both finite and quarter-wave frequency transmission zeros hence giving improved stopband performance. A complete design is presented and the fabricated low-pass filter demonstrates excellent performance in good agreement with theory. Finally, design techniques for microwave bandpass filters using re-entrant resonators are presented. The key feature is that each re-entrant resonator in the filter generates a passband resonance and a finite frequency transmission zero, above the passband. Thus an Nth degree filter can have N finite frequency transmission zeros with a simple physical realization. A new synthesis technique for pseudo-elliptic low-pass filters suitable for designing re-entrant bandpass filter has also been show-cased. A physically symmetrical 5 pole re-entrant bandpass prototype filter with 5 transmission zeros above the passband was designed and fabricated. Measured results showed good correspondence with theories

Recent Advances in Antenna Design for 5G Heterogeneous Networks

The aim of this book is to highlight up to date exploited technologies and approaches in terms of antenna designs and requirements. In this regard, this book targets a broad range of subjects, including the microstrip antenna and the dipole and printed monopole antenna. The varieties of antenna designs, along with several different approaches to improve their overall performance, have given this book a great value, in which makes this book is deemed as a good reference for practicing engineers and under/postgraduate students working in this field. The key technology trends in antenna design as part of the mobile communication evolution have mainly focused on multiband, wideband, and MIMO antennas, and all have been clearly presented, studied and implemented within this book. The forthcoming 5G systems consider a truly mobile multimedia platform that constitutes a converged networking arena that not only includes legacy heterogeneous mobile networks but advanced radio interfaces and the possibility to operate at mm wave frequencies to capitalize on the large swathes of available bandwidth. This provides the impetus for a new breed of antenna design that, in principle, should be multimode in nature, energy efficient, and, above all, able to operate at the mm wave band, placing new design drivers on the antenna design. Thus, this book proposes to investigate advanced 5G antennas for heterogeneous applications that can operate in the range of 5G spectrums and to meet the essential requirements of 5G systems such as low latency, large bandwidth, and high gains and efficiencies

Miniaturized High-Q Tunable RF Filters

This dissertation focuses on the investigation and development of novel efficient tuning techniques and the design of miniaturized high-Q tunable RF filters for high-performance reconfigurable systems and applications. First, a detailed survey of the available tuning concepts and state-of-art tunable filters is provided. Then, a novel so-called inset resonator configuration is presented for the applications of fixed and tunable coaxial filters. The design procedure of frequency tunable filters with constant absolute bandwidth (CABW) is described, and various tunable inset filters are implemented, offering many desirable merits, including the wide tuning range and stable high-Q with minimum variation. For wide octave frequency tuning ranges with CABW, a second novel concept is presented using so-called re-entrant caps tuners. Beside simplicity and compactness, this technique also features enhanced spurious performance and wider tuning capabilities than the conventional means. Also, in this dissertation, various miniaturized reconfigurable dual-band/dual-mode bandpass filters and diplexers are presented using compact dual-mode high-Q TM-mode dielectric resonators. Furthermore, a novel microfluidic-based ultra-wide frequency tuning technique for TM010-mode dielectric resonators and filters is introduced in this dissertation. In addition to the very wide tuning window, this mechanism has key advantages of low-cost, simplicity, and intrinsic switch-off. Lastly, the dissertation includes a novel bandwidth reconfiguration concept with multi-octave tuning using a single element for coaxial bandpass filters. This mechanism brings many features including the fast tuning, constant high-Q, intrinsic switch-off, and wide BW-reconfiguration

SU-8 micromachined terahertz waveguide circuits and coupling matrix design of multiple passband filters

This thesis presents the designs and measurement performance of nine SU-8 micromachined waveguide circuits operating at WR-10 band (75-110 GHz), WR-3 band (220-325 GHz) and WR-1.5 band (500-750 GHz). Two thick SU-8 photoresist micromachining processes, namely, the separate single-layer process and the joint two-layer process, are developed to fabricate these terahertz waveguide circuits. In order to achieve accurate and secure interconnections with measurement network analyzers, two calibrated measurement methods for micromachined waveguide circuits are proposed. The measurement performance of these micromachined circuits is excellent in terms of very low insertion loss. The design of multiple-passband filters using coupling matrix optimisation is also discussed in this thesis. The optimisation is performed on the coupling matrix and a genetic algorithm (GA) is employed to generate initial values for the control variables for a subsequent local optimisation (sequential quadratic programming - SQP search). The novel cost function presented in this thesis measures the difference of the frequency locations of reflection and transmission zeros between the response produced by the coupling matrix and the ideal response. An eighth-order X-band dual-band waveguide filter with all capacitive coupling irises is fabricated and measured to verify the design technique.EThOS - Electronic Theses Online ServiceGBUnited Kingdo