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This thesis presents a brief introduction to microwave components and technology. It also presents two novel dual-band designs, their analysis, topology, simulation and fabrication. In chapter 2, a novel dual-band bandpass filter using asymmetric stub-loaded stepped-impedance resonators (SLSIRs) operating at 1 and 2.6 GHz is shown. This type of design applies suitable arrangements to improve the filter’s performance. Then, in chapter 3, a novel dual-band balun (transforms unbalanced input signals to balanced output signals or vice versa) operating at 1.1 and 2 GHz with flexible frequency ratios is presented, which has more advantages in microwave applications. Then, conclusion and future works are discussed in chapter 4.

Typical microwave components such as antennas are large in size and occupy considerable space. Since multiple standards are utilized in modern day systems and thus multiple antennas are required, it is best if a single component can be reconfigured or tuned to various bands. Similarly phase shifters to provide beam scanning and polarization reconfigurable antennas are important for modern day congested wireless systems. Tunability of antennas or phase shifting between antenna elements has been demonstrated using various techniques which include magnetically tunable components on ferrite based substrates. Although this method has shown promising results it also has several issues due to the use of large external electromagnets and operation in the magnetically saturated state. These issues include the device being bulky, inefficient, non-integrable and expensive. In this thesis, we have tried to resolve the above mentioned issues of large size and large power requirement by replacing the large electromagnets with embedded bias windings and also by operating the ferrites in the partially magnetized state. New theoretical models and simulation methodology have been used to evaluate the performance of the microwave passive components in the partially magnetized state. A multilayer ferrite Low Temperature Cofired Ceramic (LTCC) tape system has been used to verify the performance experimentally. There exists a good agreement between the theoretical, simulation and measurement results. Tunable antennas with tuning range of almost 10 % and phase shifter with an FoM of 83.2/dB have been demonstrated in this work, however the major contribution is that this has been achieved with bias fields that are 90 % less than the typically reported values in the literature. Finally, polarization reconfigurability has also been demonstrated for a circular patch antenna using a low cost additive manufacturing technique. The results are promising and indicate that highly integrated ferrite based tunable components are feasible in small form factor, without the need of the large electromagnets and coils, and thus can be operated at very low bias levels as compared to the ones which are operated in the saturated state with external bias mechanisms.

Pour faire face à la complexité croissante des systèmes de télécommunications sans fil, il est nécessaire de développer des systèmes RF (Radiofréquence) plus performants et agiles. Dans ce contexte, des matériaux à changement d’état, ou SCM (State Change Material), déjà utilisés dans le développement des futures générations de mémoires non-volatiles (PCRAM, CBRAM), ont récemment été évalués pour réaliser des commutateurs RF. Parmi ces SCM, les PCM (matériaux à changement de phase) semblent ainsi être une solution particulièrement attractive pour réaliser des composants RF permettant l’obtention de circuits reconfigurables, rapides, miniatures et intégrables sur des circuits CMOS.En lien avec la stratégie du LETI / DCOS (Département COmposants Silicium) et en s’appuyant sur une analyse fine de la physique des matériaux à changement d’état, la thèse aura pour objectif de développer une nouvelle filière technologique de composants RF en rupture à base de SCM qui permettront de concevoir de nouvelles architectures de circuits RF innovants et reconfigurables. / As wireless telecommunication systems complexity continues to increase, there is a need to develop RF systems with higher performances and agility. In this context, SCM (State Change Material), already used to develop the next generation of non-volatile memory (PCRAM, CBRAM), were recently evaluated to realize RF switches. Among these SCM, PCM (Phase Change Material) are an attractive option to realize miniature and high speed reconfigurable RF components that could be easily integrated with CMOS circuits.In line with the LETI / DCOS (Silicon Components Division) strategy, PhD will aim to develop a disruptive RF components technology based on SCM that will allow designing innovative and reconfigurable FEM (Front End Module) circuits.

In recent years, the wireless industry has witnessed tremendous development for the defense and commercial segments. The explosive growth in the modern radio frequency and microwave systems leads to an increased interest in the research of miniaturized microwave circuits with superior performance. Broadband components, in particular band pass filters (BPFs) and couplers are some of the widely used components in the modern communication systems, software defined radios, cognitive radios, imaging systems and positioning radars. In order to meet these requirements, the use of innovative geometries, a thorough understanding of their behavior by appropriate analytical techniques and the use of appropriate fabrication approaches are essential. This thesis is an effort in this direction. In this thesis work, an aperture in the ground plane is used to achieve the tight coupling in the edge and broadside-coupled coupled lines which may be otherwise difficult due to the fabrication limitations. Since microstrip lines with an aperture in the ground plane are found to be very useful in various MIC and MMIC components, closed form analytical expressions developed here will be useful for their initial synthesis. The performances of components using these are enhanced using open/short circuited resonators, spurlines and stubs. A quasi-static approach has been investigated to obtain simple closed form expressions for a microstrip line with a rectangular aperture in the ground plane. The effect of a rectangular aperture in the ground plane has been incorporated in the commonly used expressions of a regular microstrip line by introducing the concept of an equivalent effective height. The expressions for the effective height microstrip geometries with defected ground are obtained and this has been further extended to various possibilities of two-conductor and three-conductor coupled lines. Analysis of the filters and the couplers are mainly based on the even and odd mode propagation characteristics of coupled lines. This approach is extended in this thesis for three conductor coupled lines. Novel broadband BPFs and couplers and dual band pass filters employing various coupled line configurations and defected ground have been developed in this research work. Most of these components have been implemented on a regular microwave laminate or LTCC medium (planar or multi-layer) and tested for the required RF performances. The experimental results were compared against the analytically computed results based on the circuit models and the full wave simulations using electromagnetic (EM) simulations for the validation. The results are in good agreement. With practical requirements of the organization in mind, additional design elements such as open circuit stubs have been incorporated in some of these designs to achieve the desired performance. It is expected that the wideband filter (3.0GHz to 3.8GHz) and the broadband coupler (4GHz to 6GHz) developed in this thesis work would be deployed in systems developed at the Central Research Laboratory, Bharat Electronics Limited, Bangalore, India. In summary, the present doctoral work strives to (i) establish a simplified analysis method for the microstrip lines and coupled microstrip lines with a rectangular aperture in the ground plane, (ii) extend the even and odd mode analysis of the coupled lines for several new coupled line configurations, (iii) design novel broadband microwave filters, dual band filter and couplers using both these, (iv) fabricate these devices using the planar technologies including LTCC, and (v) validate the analysis and design with important practical applications.

Dans les systèmes des télécommunications, beaucoup d’études ont été entreprises pour intégrer des composants passifs non réciproques. Le bon fonctionnement des circulateurs exige souvent des aimants volumineux et lourds qui assurent une orientation uniforme des moments magnétiques du matériau ferrite. Pour tendre vers l’intégration et la miniaturisation des circulateurs, les nanotechnologies peuvent offrir des solutions intéressantes. L’objectif de cette thèse a été de développer un circulateur coplanaire auto-polarisé. L'approche choisie est fondée sur la réalisation de substrats composites à «nano-fil ferrimagnétiques». Elle consiste à faire un dépôt par magnétophorèse ou dip-coating de nanoparticules de ferrite de cobalt dans des membranes d’alumine poreuses et de les orienter sous champ magnétique de manière uniforme. Des substrats composites magnétiques ont été fabriqués à partir de nanoparticules CoFe2O4 dispersées dans une matrice sol-gel de silice en utilisant la technique de Dip-coating avec et sans un champ magnétique appliqué. De nombreuses études ont été faites afin d'étudier le comportement magnétique et diélectrique de ces substrats : VSM, polarimétrie spectrale, MFM et autres. Les cycles d'hystérésis montrent une forte différence des valeurs des champs coercitifs (μ0Hc) et rémanents (Mr/Ms) si, durant la fabrication, un champ magnétique est appliqué ou non, démontrant ainsi l'orientation (ou non) des nanoparticules. Ce nano-composite est un candidat intéressant pour la fabrication de circulateurs même si la concentration et l’orientation des particules sont insuffisantes. Des circulateurs ont été conçus, modélisés et simulés à l'aide du logiciel HFSS. Suite à des résultats de simulation intéressants; un premier prototype a été fabriqué et caractérisé en hautes fréquences. Les résultats de mesure ont montré un phénomène de circulation, qui reste très faible en raison du faible pourcentage de nanoparticules magnétiques dans le composite et de leur orientation imparfaite. Les verrous technologiques ont été clairement identifiés et ne permettent pas, pour l’instant, de réaliser un circulateur opérationnel / In telecommunications systems, many studies have been undertaken to integrate non-reciprocal passive components. The proper functioning of circulators often requires large and heavy magnets that ensure a uniform orientation of the magnetic moments of the ferrite material. To work towards the integration and miniaturization of circulators, nanotechnology can offer interesting solutions. The aim of this thesis was to develop a self-biased coplanar circulator. The approach is based on the production of composite substrates "ferrimagnetic nanowire." It consists in a magnetophoresis or a dip-coating deposition of cobalt ferrite nanoparticles in porous alumina membranes and orienting them in a magnetic field uniformly. Magnetic composite substrates were made from CoFe2O4 nanoparticles dispersed in a matrix of silica sol-gel using the dip-coating technique with and without an applied magnetic field. Many studies have been made to study the magnetic and dielectric behavior of these substrates: VSM, spectral polarimetry, MFM and others. The hysteresis loops show a strong difference in the values of coercive fields (μ0Hc) and persistent (Mr / Ms) if, during the fabrication, a magnetic field is applied or not, therefore showing the orientation (or not) of nanoparticles. This nano-composite is an interesting candidate for the fabrication of circulators even if the concentration and the particle orientation are insufficient. Circulators were designed, modeled and simulated using the HFSS software. Following the interesting results of simulation; a first prototype was fabricated and characterized at high frequencies. The measurement results showed a circulation phenomenon, which is very low due to the small percentage of magnetic nanoparticles in the composite and their imperfect orientation. Technological barriers have been clearly identified and do not allow for the time to achieve an operational circulator

[ES] En los últimos años, se ha observado un crecimiento exponencial en los nuevos sistemas de comunicaciones, entre los cuales se destacan las comunicaciones inalámbricas y espaciales. Este fenómeno ha generado un incremento significativo en los requisitos de los sistemas de radiofrecuencia. Este aumento no solo se refiere a la respuesta eléctrica de dichos sistemas, sino también a otros parámetros de importancia, tales como el peso, el coste, el volumen y la integrabilidad con otras tecnologías. Con el propósito de cumplir con estos requisitos emergentes, los circuitos integrados en substrato, específicamente los denominados Circuitos Integrados en Substrato Vacío (Empty Substrate Integrated Circuits (ESIC)), se presentan como una solución altamente prometedora. Estos circuitos son reconocidos por su bajo coste, ligereza y facilidad de integración, preservando al mismo tiempo su eficacia en términos de respuesta eléctrica. La principal ventaja de esta tecnología radica en la capacidad de incorporar tanto componentes activos como pasivos, así como antenas, utilizando el mismo substrato o combinando varios de ellos mediante procesos de fabricación planar estándar. La naturaleza vacía de estos circuitos posibilita la implementación de componentes de alto rendimiento sin comprometer las características previas. En este contexto, la presente tesis doctoral se propone como objetivo central la investigación, diseño, desarrollo y fabricación de antenas y nuevos componentes de microondas utilizando tecnologías vacías integradas en substrato, con enfoque en aplicaciones para satélites de dimensiones reducidas. La tesis abordará la exploración de nuevos componentes de microondas comúnmente presentes en las cargas útiles de satélites, tales como filtros, transiciones entre tecnologías planares, divisores, entre otros, así como antenas, tanto como elementos individuales, y en agrupaciones. Estas investigaciones se realizarán en el marco de las mencionadas tecnologías emergentes, con la finalidad de lograr un grado de miniaturización, dispositivos altamente eficientes, y de bajo perfil manteniendo sus características esenciales y obteniendo respuestas mejoradas en comparación con soluciones previamente conocidas. La combinación global de los dispositivos y antenas propuestos en la tesis doctoral abre nuevas posibilidades en las tecnologías vacías integradas en substrato, contribuyendo potencialmente a mejorar la capacidad, robustez y compacidad de los sistemas de comunicaciones emergentes. / [CA] En els darrers anys, s'ha observat un creixement exponencial en els nous sistemes de comunicació, entre els quals destaquen les comunicacions sense fils i espacials. Aquest fenomen ha generat un increment significatiu en els requisits dels sistemes de radiofreqüència. Aquest augment no només es refereix a la resposta elèctrica d'aquests sistemes, sinó també a altres paràmetres d'importància, com ara el pes, el cost, el volum i la integrabilitat amb altres tecnologies. Amb la finalitat de complir amb aquests requisits emergents, els circuits integrats en substrat, específicament els anomenats Circuits Integrats en Substrat Buit (ESiC), es presenten com una solució altament prometedora. Aquests circuits són reconeguts pel seu baix cost, lleugeresa i facilitat d'integració, alhora que preserven la seva eficàcia en termes de resposta elèctrica. La principal avantatge d'aquesta tecnologia radica en la capacitat d'incorporar tant components actius com passius, així com antenes, utilitzant el mateix substrat o combinant-ne diversos mitjançant processos de fabricació planar estàndard. La naturalesa buida d'aquests circuits possibilita la implementació de components d'alt rendiment sense comprometre les característiques prèvies. En aquest context, la present tesi doctoral es proposa com a objectiu central la investigació, disseny, desenvolupament i fabricació d'antenes i nous components de microones utilitzant tecnologies buides integrades en substrat, amb un enfocament en aplicacions per a satèl·lits de dimensions reduïdes. La tesi abordarà l'exploració de nous components de microones comuns en les càrregues útils de satèl·lits, com ara filtres, transicions entre tecnologies planars, divisors, entre altres, així com antenes, tant com a elements individuals com en agrupacions. Aquestes investigacions es duran a terme en el marc de les esmentades tecnologies emergents, amb la finalitat d'assolir un grau de miniaturització, dispositius altament eficients i de baix perfil, mantenint les seves característiques essencials i obtenint respostes millorades en comparació amb solucions prèviament conegudes. La combinació global dels dispositius i antenes proposats en la tesi doctoral obre noves possibilitats en les tecnologies buides integrades en substrat, contribuint potencialment a millorar la capacitat, robustesa i compacitat dels sistemes de comunicació emergents. / [EN] In recent years, there has been an exponential growth observed in emerging communication systems, among which wireless and space communications stand out prominently. This phenomenon has led to a significant increase in the requirements of radiofrequency systems. This escalation pertains not only to the electrical response of such systems but also extends to other critical parameters, including weight, cost, volume, and integrability with other technologies. In order to meet these emerging requirements, integrated circuits on substrate, specifically those Empty Substrate Integrated Circuits (ESIC), emerge as a highly promising solution. These circuits are acknowledged for their low cost, lightweight nature, and ease of integration, while simultaneously preserving their effectiveness in terms of electrical response. The primary advantage of this technology lies in its capability to incorporate both active and passive components, as well as antennas, utilizing the same substrate or combining multiple substrates through standard planar manufacturing processes. The empty nature of these circuits enables the implementation of high-performance components without compromising their inherent characteristics. In this context, the central objective of this doctoral thesis is to investigate, design, develop, and manufacture antennas and new microwave components using empty substrate integrated technologies, with a focus on applications for small-scale satellites. The thesis will address the exploration of new microwave components commonly found in satellite payloads, such as filters, transitions between planar technologies, dividers, among others, as well as antennas, both as individual elements and in arrays. These investigations will be conducted within the framework of the aforementioned emerging technologies, aiming to achieve a degree of miniaturization, highly efficient devices, and low profile while maintaining essential characteristics and obtaining improved responses compared to previously known solutions. The collective integration of the proposed devices and antennas in this doctoral thesis opens up new possibilities in empty substrate integrated circuits, potentially contributing to enhancing the capacity, robustness, and compactness of emerging communication systems. / Herraiz Zanón, D. (2024). Antenas y componentes de microondas para satélites de dimensiones reducidas utilizando tecnologías vacías integradas en substrato [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/204589