Reconfigurable Cavity Filters with Contactless Tuners
The recent development of tunable microwave filters has shown their great potential for being an integral component in future wireless systems across a wide range of applications. In the last decade, filters based on tunable evanescent-mode (EVA) cavity resonators have demonstrated a high performance with high quality factor (Q), wide tuning range and high power handling. However, the implementation of these filters suffers from reliability issues and integration complexity which restricted the practical utilization of these filters in different real-system applications. This dissertation will present and evaluate several practical and novel solutions to overcome these practical challenges without compromising the filter performance.
The first part of the dissertation focuses on the design of quasi-absorptive bandstop filters with passive absolute bandwidth compensation utilizing micromachined cavity filters. The second part of the dissertation presents a novel method to tune substrate-integrated-waveguide (SIW) cavity filters using contactless tuners. In this work, a new tuning mechanism is proposed to overcome the mechanical reliability issues and the sensitive assembly of conventional tunable cavity filters. Furthermore, a new utilization of dual-mode SIW resonators is introduced in order to improve response selectivity and realize constant absolute bandwidth filters without compromising filter size and performance.