A Novel UWB Filter with Dual-notch-bands Characteristic Using Radial-multimode Loaded Stub Resonator

摘要

this paper presents a novel approach for designing compact ultra-wideband (UWB) band-pass filter with a good dual-notched band characteristic. By using a radial-multimode loaded stub resonator, one notch-band can be got. Another notch-band can be generated by the half-wavelength parasitic micro-strip Resonator. The main advantage of the proposed filter is the frequency of the notched band can be tuned easily in a wide frequency range. The first notch-band can be changed from 4 GHz to 6 GHz. The second notch-band can be changed from 7 GHz to 9 GHz. Electric filed distribution 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, filter is designed and fabricated. Measured results show the proposed UWB properties from 3 to 10.8 GHz. The UWB filter's dual-notch-bands whose center frequencies are 4.5 GHz and 7.7 GHz and have 10 dB fractional bandwidths of about 2.2% and 1.3%, respectively. 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.