A $Ku$ -Band High-$Q$ Tunable Filter With Stable Tuning Response

A Ku-band tunable filter with a very stable notch level and in-band RF performance is presented in this paper. A new coupling iris configuration for stable RF performance over the tuning range is realized. The filter employs two dual-mode TE
₁₁₃
tunable cavity resonators with a set of flexible bellows. A tuning range of more than 500 MHz at 12 GHz while maintaining a high Q is demonstrated using the introduced resonator. Design techniques, including an RF-mechanical tradeoff analysis, are detailed and addressed.