Reconfigurable Dielectric TM-Mode Bandpass Filter Using Dielectric Tuners

This article addresses the use of dielectric tuners in low-loss reconfigurable bandpass filters based on TM<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">010</inf>-mode dielectric resonators. A fully reconfigurable 4th-order L-band filter is presented with adaptable center-frequency and band-width. Based on the tuning requirements, the design is explored in terms of resonator topology, as well as of inter-resonator and input/output coupling levels. The proposed filter is successfully designed, manufactured, and measured, demonstrating a clear agreement between simulated and experimental results. Using dielectric zirconia rods, the implemented prototype successfully exhibited efficient center-frequency tuning between 1.4 – 1.9 GHz with low-loss and high quality-factor larger than 1200. Also, the absolute bandwidth (BW) is reconfigured effectively from 60 MHz to 100 MHz.