PULSE INJECTION FOR REAL-TIME MONITORING OF TUNABLE HIGH-Q FILTERS

A new measurement technique for monitoring the frequency of high-Q microwave tunable filters in real time is presented in this work. Relying on the natural response of a cavity resonator, the technique provides the operating frequency information in a binary digital format, making it easy to read and process. The presented methodology is experimentally demonstrated on band-stop filters, implemented by highly loaded substrate-integrated cavities in the 1.5 GHz range. Measured results show that the changes in frequency as small as 2-20 MHz (0.13-1.3%) can be detected for a tunable cavity filter (1.42-1.65 GHz) within 1 ms, based on commercial-off-the-shelf components. © 2014 Wiley Periodicals, Inc.