K-Band Frequency Tunable Substrate-Integrated- Waveguide Resonator Filter With Enhanced Stopband Attenuation

In this paper, we present a K-band substrate-integrated waveguide resonator bandpass filter structure. The filter uses an antisymmetric mode of the resonator for the first time. A design method for the external coupling structure of the resonator utilizing the antisymmetric mode is described. In addition, a methodology for suppressing neighboring resonances close to the passband is demonstrated. This method can enhance stopband attenuation performance without additional loss. The proposed filter can tune the center frequency by adjusting tuning components. In order to verify the proposed filter structure and design method, we have fabricated and measured a K-band filter and demonstrated higher order filter design.