Compact Ultra-Wideband Printed Bandpass Filter Based on Coupled-Line Resonator Loading

摘要

In this paper, a novel compact design for Ultra-Wideband (UWB) Bandpass Filter (BPF) using a coupled line resonator is proposed. The proposed filter consists of two identical wideband coupling section as input and output stages. In addition, the middle section is loaded with two identical parallel resonators to enhance the out of band rejection by introducing transmission zeros. The proposed filter is implemented using microstrip line technology. The proposed design offers an UWB covering the S, C and G bands used for radar applications starting at 2.5 GHz up to 7 GHz with a matching level exceeding 20 dB. The overall size of the proposed filter is shorter than a half wavelength at the center frequency. The design procedure as well as the final results of the proposed design are illustrated based on two different numerical solutions for outcomes validation.