Low-cost high-performance frequency-tunable substrate integrated waveguide filter structure and fabrication method

This paper presents a new frequency-tunable substrate-integrated waveguide (SIW) filter structure and its fabrication method. The center frequency of the filter is adjusted by moving the membrane structure in each resonator, and the presented fabrication method mainly focuses on how to minimize the number of fabrication steps for constructing the flexible membrane. Due to the simplified process, the filter has advantages of low cost and low risk fabrication. The comparison between a conventional fabrication procedure and the new proposed method is described. For verifying the presented filter structure and fabrication method, two frequency- tunable SIW bandpass filters of the presented structure have been implemented using the presented fabrication method. It is shown that the measured response agrees well with the simulated one. The minimum insertion loss is 0.85 dB, demonstrating that high quality factor can be achieved.