Full-wave characterization of bi-dimensional cavities and its application to the design of waveguide filters and multiplexers

[EN] Modern communications systems impose stringent requirements on the equipment that operates at microwave frequency, especially in the case of wireless communications. The design of passive components for these applications is contingent upon the availability of accurate electromagnetic (EM) modeling tools that can efficiently handle the complex geometry of these components. Despite the widespread use of mesh-based general-purpose computer-aided engineering (CAE) tools to perform final design verifications, their application during the optimization process is limited. Optimum designs require a large number of simulations, which are computationally expensive when performed by general purpose tools. Instead, microwave designers prefer to employ faster software tools tailored to specific geometries, such as waveguide components, multilayered structures, etc. Therefore, the development of faster and more efficient specialized EM tools has a direct impact on the design of microwave components, both quantitatively and qualitatively. Increasingly complex geometries are modeled more accurately, and may be incorporated into novel designs without penalizing development time and its associated costs. By doing so, passive components become more advanced and are able to fulfill stricter requirements. At the same time, new research and development opportunities arise in order to address the challenges posed by these advanced structures. The present thesis is focused on a specific type of waveguide cavity geometry: bi-dimensional structures of arbitrary shape. Most microwave components based on rectangular waveguides include these elements (bends, T-junctions, tapers, power-dividers, etc.), thus the scope of this work is wide. To characterize these structures, an efficient full-wave modal formulation is developed. Taking into account common properties of bi-dimensional structures, such as its electromagnetic symmetry, the resulting technique is very efficient and accurate. Thanks to the integration of this formulation into a CAE tool, a designer is able to solve complex systems that combine this type of element with components of vastly different shapes. The developed formulation is first applied to the analysis and design of passive components, such as filters, multiplexers and orthomode transducers. These examples are employed to validate the results, as well as to demonstrate the improvement that the proposed analysis technique represents over well-known commercial EM packages. Likewise, this formulation is combined with the tool SPARK3D to predict RF breakdown (multipactor and corona) in selected bi-dimensional structures. Then, novel implementations of waveguide quasi-elliptic filters, based on the interconnection of bi-dimensional cavities, are proposed. Special attention is paid to the realization of multiple transmission zeros (TZs) with tuning-less compact structures. First, a novel family of filters, known as hybrid-folded rectangular waveguide structures, is studied. Simple and flexible methods to prescribe the location of the transmission zeros realized by these structures are presented. Practical aspects related to their physical implementation are also discussed. Secondly, a compact and purely capacitive obstacle, capable of realizing multiple TZs, is presented and discussed. In both cases, multiple examples are given to illustrate the step-by-step process involved in the design of these structures. Finally, a systematic procedure for the design of wideband manifold-coupled multiplexers is proposed. To preven the generation of undesired resonances, stubs that connect the filters to the manifold are removed. Likewise, the manifold length is kept as short as possible. Following a simple procedure, based on analytical formulas and EM simulations, a good starting point for the final optimization of these structures is obtained. It has been applied to a wideband quadruplexer for passive intermodulation measurement at C-band.[ES] Actualmente, los sistemas de comunicaciones imponen unos requisitos muy estrictos sobre el equipamiento en la banda de microondas. El diseño de estos componentes está supeditado, frecuentemente, a la disponibilidad de herramientas de modelado electromagnético (EM) que sean capaces de analizar geometrías complejas. A pesar del amplio uso de herramientas CAE (computer-aided engineering) de propósito general para la verificación final de prototipos, su potencial aplicación durante el proceso de diseño es limitada. Los diseños óptimos exigen realizar una gran cantidad de simulaciones EM. Dado que las simulaciones con estas técnicas tienen un alto coste computacional, los diseñadores suelen optar por emplear herramientas software especializadas en las estructuras que diseñan. Por tanto, el desarrollo de nuevas herramientas más precisas y eficientes ayudará a reducir el tiempo de diseño de estos productos, y con ello los costes asociados. Además, permitirá abrir nuevas líneas de investigación para responder a los retos que plantean geometrías cada vez más complejas. Esta tesis se centra en el desarrollo de una herramienta de análisis EM para un tipo concreto de estructuras: cavidades bidimensionales de sección arbitraria. Es habitual encontrar este tipo de estructuras en la mayoría de componentes implementados en guía rectangular. Por tanto, el rango de aplicación de la teoría desarrollada en esta tesis es muy amplio. En concreto, se ha desarrollado una nueva formulación basada en métodos modales que permite realizar una caracterización de onda completa de estas estructuras de forma eficiente y precisa. Al aprovechar su simetría geométrica y electromagnética, la herramienta desarrollada puede minimizar los cálculos a realizar, consiguiendo grandes velocidades de computación pero manteniendo una alta precisión. Gracias a la integración de esta formulación dentro de una herramienta CAE basada en métodos modales, se ofrece la posibilidad a los diseñadores de resolver sistemas muy complejos que combinan este tipo de cavidades con otros componentes de geometrías distintas. Esta formulación se aplica, en primer lugar, al análisis y diseño de componentes pasivos comunes, tales como filtros, multiplexores y OMTs. Estos ejemplo validan la herramienta desarrollada, y demuestran la significativa mejora que supone el uso de esta nueva técnica con respecto a otros paquetes software de análisis electromagnético. Asimismo, al combinar esta formulación con la herramienta SPARK3D se abre la posibilidad de predecir la aparición de fenómenos de descarga de alta potencia en determinadas estructuras bidimensionales. A continuación, se proponen nuevas formas de implementar filtros cuasi-elípticos basados en la interconexión de cavidades bi-dimensionales. Se hace especial hincapié en la realización de múltiples ceros de transmisión mediante estructuras compactas que no requieran sintonía. Por una parte se estudian los filtros hybrid-folded rectangular waveguide. Este trabajo incluye una discusión en profundidad sobre distintas implementaciones de este tipo de filtros. En ella se consideran aspectos prácticos relacionados con su uso e implementación física, que ofrecen al diseñador unos criterios claros para elegir la estructura que más se ajuste a sus especificaciones. Por otra parte se presenta un nuevo obstáculo de naturaleza capacitiva muy compacto, que permite la realización de múltiples ceros de transmisión incluso en estructuras en línea. En ambos casos se incluyen ejemplos de aplicación y se describe la metodología seguida para su diseño. Finalmente, se expone un procedimiento sistemático para diseñar multiplexores de banda ancha. Para prevenir la generación de resonancias indeseadas se evitan, en la medida de lo posible, las interconexiones mediante tramos cortos de guía. Siguiendo una metodología simple se consigue un excelente punto inicial para su optimización. La te[CA] Els actuals sistemes de comunicacions sense fils imposen uns requisits molt estrictes sobre l'equipament de la banda de microones. El disseny d'aquests components està supeditat, frequentment, a la disponibilitat de ferramentes de modelatge electromagèntic (EM) que siguen capaços de gestionar geometries complexes. Tot i l'ampli ús de ferramentes CAE (computer-aided engineering) de propòsit general per a la verificació final de prototips, la seua aplicació durant el procés de disseny és limitada. Els dissenys òptims exigeixen realitzar una gran quantitat de simulacions. Les simulacions amb aquestes tècniques tenen un alt cost computacional, per tant els dissenyadors solen optar per utilitzar ferramentes software especialitzades en les estructures que dissenyen. Per tant, el desenvolupament de noves tècniques d'anàlisi més precises i eficients ajudarà a reduir el temps de desenvolupament d'aquests productes, i dels seus costos associats. A més permetrà obrir noves línies d'investigació per respondre els reptes que plantegen geometries cada vegada més complexes. Aquesta tesi es centra en el desenvolupament d'una ferramenta d'anàlisi EM per a un tipus concret d'estructures: cavitats bidimensionals de forma arbitraria. És habitual trobar aquestes estructures en la majoria de components implementats en guia rectangular. Per tant, l'àmbit d'aplicació de la teoria presentada en esta tesi és molt ampli. En concret, s'ha desenvolupat una nova formulació basada en mètodes modals que permet realitzar una caracterització d'ona completa d'aquestes estructures de forma eficient i precisa. Aprofitant la seua simetria geomètrica i electromagnètica, la ferramenta desenvolupada pot minimitzar els càlculs a realitzar, aconseguint grans velocitats de càlcul mantenint una alta precisió. Gràcies a la integració d'aquesta formulació dins d'una ferramenta CAE basada en mètodes modals, s'ofereix la possibilitat als dissenyadors de resoldre sistemes molt complexos que combinen aquest tipus de cavitats amb altres components de diferent geometria. Aquesta formulació s'aplica, en primer lloc, a l'anàlisi i disseny de components passius comuns: filtres, multiplexors i OMTs. Aquests exemples serveixen per a validar la ferramenta desenvolupada, així com demostrar la significativa millora que suposa l'ús d'aquesta nova tècnica respecte d'altres paquets software d'anàlisi electromagnètic. Així mateix, mitjançant la combinació d'aquesta formulació amb la ferramenta SPARK3D s'obri la possibilitat de predir l'aparició de fenòmens de descàrrega d'alta potència en estructures bidimensionals. A continuació, es proposen noves formes d'implementar filtres quasi el-líptics en guia d'ona basats en la interconnexió de cavitats bidimensionals. Es fa especial èmfasi en la realització de múltiples zeros de transmissió mitjançant estructures compactes que no requereixen de sintonia. D'una banda s'estudien els filtres hybrid folded rectangular waveguide. Aquest treball inclou una discussió en profunditat sobre diferents implementacions d'aquest tipus de filtres. S'hi consideren aspectes pràctics relacionats amb el seu ús i implementació física, que ofereixen al dissenyador uns criteris clars per triar l'estructura que més s'ajuste a les seues especificacions. D'altra banda es presenta un nou obstacle de naturalesa capacitiva extremadament compacte, que permet la realització de múltiples zeros de transmissió fins i tot en estructures en línia. En els dos casos s'inclouen exemples d'aplicació i es descriu la metodologia seguida per al seu disseny. Finalment, s'exposa un procediment sistemàtic per dissenyar multiplexors de banda ampla. Per prevenir la generació de ressonàncies no desitjades s'eviten les interconnexions amb trams de guia curts. Seguint una metodologia simple, basada en fórmules analítiques i simulacions electromagnètiques, s'aconsegueix un excel-lent punt inicial per a l'optimització.Carceller Candau, C. (2016). Full-wave characterization of bi-dimensional cavities and its application to the design of waveguide filters and multiplexers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/64089TESI

Evaluación de competencias transversales en la asignatura Proyecto

[ES] La asignatura Proyecto, ubicada en el 10º cuatrimestre de los estudios de Ingeniería de Telecomunicación de la Universidad Politècnica de València (UPV), nació en el curso 2012- 2013 a raíz de los requerimientos impuestos por la entidad de acreditación ABET (Accreditation Board for Engineering and Technology) [1]. Con esta asignatura se busca trabajar una serie de competencias transversales definidas por ABET que todo Ingeniero de Telecomunicación debe poseer al término de sus estudios.Cabedo Fabres, M.; Carceller Candau, C.; Reig, J. (2014). Evaluación de competencias transversales en la asignatura Proyecto. En JIDTEL 2014 - Jornadas de Innovación Docente 2014 - En homenaje a Elvira Bonet. Editorial Universitat Politècnica de Valencia. 1-12. http://hdl.handle.net/10251/5488911

Capacitive Obstacle Realizing Multiple Transmission Zeros for In-Line Rectangular Waveguide Filters

(c) 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other worksThis paper presents a capacitive obstacle for rectangular waveguide filters capable of realizing multiple transmission zeros (TZs). By combining a capacitive window with multiple thin stubs, a filter designer has the ability to control the total coupling implemented by the obstacle, and the frequency location of the TZs generated. The resulting structure is compact, and can be employed at the input/output and intermediate stages of direct-coupled-resonator filters. This letter includes a parametric analysis of the obstacle and practical design guidelines. To validate its practical application, an in-line five-pole filter realizing three TZs has been successfully realized.This work was supported by the Spanish Ministerio de Economia y Competitividad under R&D project TEC2013-47037-C5-1-R.Carceller Candau, C.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M. (2016). Capacitive Obstacle Realizing Multiple Transmission Zeros for In-Line Rectangular Waveguide Filters. IEEE Microwave and Wireless Components Letters. 26(10):795-797. https://doi.org/10.1109/LMWC.2016.2605462S795797261

Design of Compact Wideband Manifold-Coupled Multiplexers

The design of manifold-coupled multiplexers for wideband applications is considered in this paper. A systematic procedure, based on the sequential connection of filters to the manifold and subsequent adjustment of the interconnection elements, is presented. The filters are attached to the manifold without using stubs in order to minimize the effect of spurious resonances. The interconnection elements, the manifold, and the remaining filters are considered as the first inverter of each new filter that is attached. This technique has been applied to several practical examples. The obtained results validate the proposed design methodology.This work was supported by the Spanish Ministerio de Economi-a y Competitividad under Research and Development Project TEC2013-47037-C5-1-R.Carceller Candau, C.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M.; Gil Raga, J. (2015). Design of Compact Wideband Manifold-Coupled Multiplexers. IEEE Transactions on Microwave Theory and Techniques. 63(10):3398-3407. https://doi.org/10.1109/TMTT.2015.2460738S33983407631

EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D

This article aims at the industry interest on automated design tools that are able to take into account manufacturing effects. First, an efficient design strategy for bandpass waveguide filters including the rounded corners arising from low-cost manufacturing procedures is presented. This technique is based on a recent enhanced prototype and synthesis methodology able to consider the real structure parts. Using the resulting electromagnetic (EM)-based synthesis technique, an excellent structure is extracted, which requires, at most, only a slight final EM optimization. Second, this article presents analytical expressions providing error estimates for the different filter performances in terms of manufacturing tolerances. From such expressions, designers can determine the tolerance to be requested for a tuning-less implementation. Moreover, they can also be used to set the convergence criterion for the synthesis procedure. A fully automated design tool of bandpass waveguide filters able to consider manufacturing impairments has been developed and integrated in the commercial software Full-wave EM Simulation Tool 3D (FEST 3D)The authors thank Mrs. Eva Tarin, Mr. Oscar Monerris, and Mr. Jaime Armendariz for their work on the integration of the synthesis tool for H-plane waveguide filters in FEST 3D. This work was supported by Ministerio de Educacion y Ciencia, Spanish Government, under the Research Project ref. TEC2010-21520-C04-01.Soto Pacheco, P.; Boria Esbert, VE.; Carceller Candau, C.; Vicente Quiles, CP.; Gil Raga, J.; Gimeno Martinez, B. (2012). EM Based Synthesis and Design of Bandpass Waveguide Filters Including Manufacturing Effects with FEST3D. International Journal of RF and Microwave Computer-Aided Engineering. 22(1):93-103. https://doi.org/10.1002/mmce.2058893103221Reiter, J. M., & Arndt, F. (1995). Rigorous analysis of arbitrarily shaped H- and E-plane discontinuities in rectangular waveguides by a full-wave boundary contour mode-matching method. IEEE Transactions on Microwave Theory and Techniques, 43(4), 796-801. doi:10.1109/22.375226Zhou, J., Duan, B., & Huang, J. (2010). Influence and tuning of tunable screws for microwave filters using least squares support vector regression. International Journal of RF and Microwave Computer-Aided Engineering, 20(4), 422-429. doi:10.1002/mmce.20447Nikolova, N. (2008). Electromagnetic software in microwave engineering [Guest Editorial]. IEEE Microwave Magazine, 9(6), 10-12. doi:10.1109/mmm.2008.929880Boria, V. E., Gimeno, B., Marini, S., Taroncher, M., Cogollos, S., Soto, P., … Gil, J. (2007). Recent advances in modeling, design, and fabrication of microwave filters for space applications. International Journal of RF and Microwave Computer-Aided Engineering, 17(1), 70-76. doi:10.1002/mmce.20199Kozakowski, P., & Mrozowski, M. (2002). Gradient-based optimization of filters using FDTD software. IEEE Microwave and Wireless Components Letters, 12(10), 389-391. doi:10.1109/lmwc.2002.804561Boria, V. E., Bozzi, M., Bruni, F., Cogollos, S., Conciauro, G., Gimeno, B., & Perregrini, L. (2003). Efficient analysis of in-line waveguide filters and frequency-selective surfaces with stepped holes. International Journal of RF and Microwave Computer-Aided Engineering, 13(4), 306-315. doi:10.1002/mmce.10087Morro, J. V., Esteban, H., Boria, V. E., Bachiller, C., & Belenguer, A. (2008). Optimization techniques for the efficient design of low-cost satellite filters considering new light materials. International Journal of RF and Microwave Computer-Aided Engineering, 18(2), 168-175. doi:10.1002/mmce.20264Hunter, I. (2001). Theory and Design of Microwave Filters. doi:10.1049/pbew048eSoto, P., Tarin, E., Boria, V. E., Vicente, C., Gil, J., & Gimeno, B. (2010). Accurate Synthesis and Design of Wideband and Inhomogeneous Inductive Waveguide Filters. IEEE Transactions on Microwave Theory and Techniques, 58(8), 2220-2230. doi:10.1109/tmtt.2010.2052668Morini, A., Venanzoni, G., & Rozzi, T. (2006). A new adaptive prototype for the design of side-coupled coaxial filters with close correspondence to the physical structure. IEEE Transactions on Microwave Theory and Techniques, 54(3), 1146-1153. doi:10.1109/tmtt.2005.864112Morini, A., Venanzoni, G., Farina, M., & Rozzi, T. (2007). Modified Adaptive Prototype Inclusive of the External Couplings for the Design of Coaxial Filters. IEEE Transactions on Microwave Theory and Techniques, 55(9), 1905-1911. doi:10.1109/tmtt.2007.904329Cogollos, S., Marini, S., Boria, V. E., Soto, P., Vidal, A., Esteban, H., … Gimeno, B. (2003). Efficient modal analysis of arbitrarily shaped waveguides composed of linear, circular, and elliptical arcs using the BI-RME method. IEEE Transactions on Microwave Theory and Techniques, 51(12), 2378-2390. doi:10.1109/tmtt.2003.819776Levy, R. (1967). Theory of Direct-Coupled-Cavity Filters. IEEE Transactions on Microwave Theory and Techniques, 15(6), 340-348. doi:10.1109/tmtt.1967.1126471Balasubramanian, R., & Pramanick, P. (1999). Computer aided design ofH-plane tapered corrugated waveguide bandpass filters. International Journal of RF and Microwave Computer-Aided Engineering, 9(1), 14-21. doi:10.1002/(sici)1099-047x(199901)9:13.0.co;2-

Advanced Compact Setups for Passive Intermodulation Measurements of Satellite Hardware

(c) 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this[EN] This paper provides the guidelines for the practical development of novel advanced test beds for passive intermodulation(PIM) measurements. The proposed test beds show high performance and are flexible, allowing for the measurement of several PIM signals of different orders, with two or more input carriers. In contrast to classic test beds for satellite hardware, based on the cascaded connection of several elements, an integrated solution involving the minimum number of hardware pieces is proposed. The result is a lower number of flanged interconnections, thus reducing residual PIM level and insertion losses. In addition, return loss degradation and harmful spurious generation in the interconnections are also avoided. Measurement test beds for conducted and radiated PIM, in both transmitted and reflected directions, are discussed, highlighting the benefits and drawbacks of each configuration. Design guidelines for the key components are fully discussed. Illustrative application examples are also reported. Finally, excellent experimental results obtained from low-PIM measurement setups, working from C-band to Ka-band, are shown, thus fully confirming the validity of the proposed configurations.This work was supported in part by the European Space Agency through several research and development contracts, in part by the Ministerio de Economia y Competitividad (Spanish Government) under Project TEC2016-75934-C4-1-R, and in part by the ESA-VSC High Power RF Space Laboratory.Smacchia, D.; Soto Pacheco, P.; Boria Esbert, VE.; Guglielmi, M.; Carceller Candau, C.; Ruiz-Garnica, J.; Galdeano, J.... (2018). Advanced Compact Setups for Passive Intermodulation Measurements of Satellite Hardware. IEEE Transactions on Microwave Theory and Techniques. 66(2):700-710. https://doi.org/10.1109/TMTT.2017.2783383S70071066

Análisis Eficiente de Cavidades Plano E Mediante BI-RME 2D y Ecuación Integral

[ES] El trabajo propuesto se centra en el análisis electromagnético preciso y eficiente de cavidades de sección transversal arbitraria en configuración plano E. Combinando el método BI-RME en su versión 2D con la resolución adicional de un problema de ecuación integral, se consigue caracterizar estas estructuras a través de su Matriz Generalizada de Admitancias (MAG) de forma muy eficiente. El método BI-RME, tradicionalmente empleado para analizar guías de sección arbitraria, se utiliza en este trabajo para calcular la serie rápidamente convergente de la MAG. Sin embargo, la serie de términos que involucra a los modos irrotacionales se calcula de manera más eficiente al resolver un problema electromagnético de ecuación integral mediante el Método de los Momentos. En este Trabajo Fin de Máster se detallan los aspectos teóricos más relevantes de la implementación realizada. Tras la implementación de este módulo, se ha integrado dentro de las herramientas de análisis electromagnético propias del grupo de investigación. De esta manera, se han analizado toda una serie de estructuras y dispositivos de uso habitual en sistemas de comunicaciones reales que incluyen cavidades como las consideradas en este trabajo. Los resultados de todos estos análisis han servido para validar la precisión y eficiencia numérica de la implementación realizada, comparando, para ello con medidas y simulaciones extraídas de la literatura técnica.[EN] The efficient and accurate analysis of E-plane cavity resonators with arbitrary cross section is considered in this work. Combining the well-known 2D BI-RME method with the solution of an additional integral equation problem, the Generalized Admittance Matrix (GAM) of this cavity is computed very efficiently. The BI-RME method is used to compute the rapidly-converging series of coupling coefficients present in the expression of the GAM. However, the series of coupling coefficients related to irrotational modes are more efficiently computed as the solution of an integral equation electromagnetic problem. The Master's Thesis contains all the theoretical details behind the implementation. After integrating this algorithm with other available modal methods developed by the research group, a series of structures have been analyzed in order to check the accuracy and numerical efficiency of the implementation. The results, included in the document, are successfully compared with data obtained from the technical literature.Carceller Candau, C. (2012). Análisis Eficiente de Cavidades Plano E Mediante BI-RME 2D y Ecuación Integral. http://hdl.handle.net/10251/27447.Archivo delegad