Synthesis and design of dissipative filters with improved performance
- Autores: Alberto Padilla Díaz
- Directores de la Tesis: Jordi Mateu Mateu (dir. tes.)
- Lectura: En la Universitat Politècnica de Catalunya (UPC) ( España ) en 2015
- Idioma: inglés
- Tribunal Calificador de la Tesis: Fermin Elias Mira Perez (presid.), Juan Carlos Collado Gómez (secret.), Faouzi Bader (voc.)
- Programa de doctorado: Programa de Doctorado en Teoría de la Señal y Comunicaciones por la Universidad Politécnica de Catalunya
- Materias:
- Enlaces
- Tesis en acceso abierto en: TDX
- Resumen
Connect, upload, download, share and transfer anything at anytime and anywhere is not a futuristic vision and is indeed a real demand on current and future wireless and fixed communication systems. From the point of view of service providers, efficient usage of the limited resources on the radio frequency (RF) spectrum is one of the biggest challenges. This technological challenge have to be faced from many different approaches and one is certainly the RF hardware equipment on the wireless devices, base stations and satellite equipment. Among the RF components into the RF chain, the filtering stage is without any doubt one of the most critical components, which usually have to be individual for any communication system or have to operate in a multistandard and multimode communication environment. Our devices are equipped with more and more radios and there are many scenarios where it is desirable from a user perspective to operate these simultaneously. Adding to the challenges, many of these bands are very close together and therefore require highly selective filters. When this happens it is essential that they can operate without detrimental mutual interference. These bands must be isolated to avoid interference. This demands for continuous research on filter a) performance improvement and b) size reduction. This is even more stringent in satellite equipment where the live of the device is longer and the size and weight of the equipment significantly contributes to the payload of the satellite and strongly affects the cost. The number of selective or channelizing filters in a satellite equipment are numerous and present into the input multiplexing, always present in any satellite transponder. Channel filters in input multiplexers take up a substantial portion of modern satellite payloads in terms of size and mass. High selective filters can be achieved by the use of high quality factor resonators on the implementation of high order filter with usually a complex configuration - several transmission zeros to increase and tailored the selectivity and equalization zeros to obtain a linear group delay response of the filter. Although several innovative technologies can achieve high performance filter with a considerable compact size, the required filter response flexibility and heritage demanded on the on-board satellite equipment, demands for using conventional technologies for the filter implementation. This results in bulky filter configurations, where a size reduction inherently involves a reduction on the quality factor, which in turn give rises into a degradation of the filter performance. The goal of this work is the implementation of a new class of filters with the used of lossy resonators. Note that success of this goal will result in high performance filter with reduced sized and suitable to be used in satellite equipment. The size reduction, in this novel class of filters, comes along an increment of the overall filter insertion losses, although the filter shape factor it is still high-performed. Although this limits the application of such new class of filters, there are very promising in RF input front-end architectures where the filter (or input multiplexer filtering stage) connects after and amplifier structures, as in a satellite equipment. This demands for achieving three intermediate goals: 1) create a new mathematical formulation of the filter response which considers the limited losses of the resonators from the very beginning, 2) provide the suitable synthesized network of the new filter topologies. This new topologies usually results in conventional topologies with an additional coupled resistive network which provides a selective dissipation along the filter band, and 3) evaluate the technological issues for the implementation of this new class of filters. The later objective have been achieved by the implementation of three prototypes.
