A novel UWB filter with notch-band characteristic using radial-loaded stub resonator

Abstract

This paper presents a novel approach for designing compact ultra-wideband (UWB) bandpass filter with a good notched band characteristic. A notch band characteristic is obtained by using the radial-loaded stub resonator. The main advantage of the proposed filter is that the frequency of the notched band can be tuned easily in a wide frequency range. Current density and equivalent model is also given depending on the odd/even excitation resonance condition. The characteristics of the filter are analyzed. To verify the proposed methods, a filter is designed and fabricated. Measured results show that the proposed UWB properties from 3 to 10.2GHz and the notch band can be changed optionally from 5GHz to 9GHz. These filters can be integrated in UWB radio systems and efficiently enhance the interference immunity from undesired signals such as wireless local area network (WLAN) and WiMAX.