Study on the performance of novel planar dual-mode microstrip bandpass filter

Abstract

A novel planar dua1-mode elliptic-function microstrip bandpass filter with two triangle corner cuts and a square notch is proposed, and the performance of the designed filter is studied in detail. The proposed filter structure uses a single patch without coupling gaps. The center frequency is about 2.13GHz. The 3dB fractional bandwidth is 9.86%, and the minimum insertion loss in the passband is 0.13dB.There are two transmission zeros on both sides of the passband. The insertion loss is < 1dB and return loss is > l0dB within 2.08–2.22GHz. The effect on the filter's performance by changing filter parameters is studied. The results show that this new filter can provide a low insertion loss and reduce uncertainty in fabrication. It also makes miniaturization easy.