TUNABLE FILTER BANK USING EVANESCENT MODE CAVITY FILTERS FOR SPECTRUM SCANNING

Abstract

Future generations of communications systems will require unprecedented spectrum agility to share the spectrum amongst multiple users. Several technological challenges need to be addressed to realize such systems. One challenge is the continuous monitoring and mapping of the radio frequency spectrum. A logical solution to the problem is to use a sensitive, wideband receiver to capture the spectrum. There are some drawbacks to capturing a large frequency range simultaneously, most notably sensitivity to interfering signals and higher noise levels. Both issues can be mitigated by using filters to reduce the bandwidth and split the capture into smaller frequency ranges. In this thesis, the objective is to create a tunable filter bank to allow for frequency selectivity in front of a sensitive, wideband receiver. To realize this tunable filter bank, evanescent-mode (EVA) cavity filters are implemented having demonstrated high performance in past studies. When a large interfering signal is present, then a filter is tuned into the receive path to eliminate the interference. This thesis will present the concept, fabrication and results of the proposed tunable filter bank.