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 10.2 GHz and the notch band can be changed optionally from 5 GHz to 9 GHz. 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.