Design of a Bandpass Filter with Reconfigurable Finite Transmission Zeros

In this paper, a novel reconfigurable bandpass filter is introduced. By choosing the right coupling polarity of cross-couplings between non-adjacent cavities, as well as the proper value of main-couplings and cross-couplings, different number and locations of finite transmission zeros of the filter can be realized. As an example, a 4-cavity FM bandpass filter is designed, which can realize 7 different filter responses only by convenient filter tuning.