Microwave bandpass filter using QMSIW

A planar bandpass filter based on a technique that utilizes quarter mode of substrate integrated waveguide (SIW) is presented. This concept reduces the circuit foot print of SIW to a quarter of its size, along with miniaturization good performance and high quality factor is maintained by the structure. The design concept for single-pole resonator structure is presented; and by coupling the resonators a two-pole substrate integrated waveguide bandpass filter is achieved for the frequency of 5.9 GHz. The results show that the filter insertion losses are better than 2 dB and return losses are less than 20 dB. The measured frequency response is in good agreement with the simulated response in the region of interest.