Design of a Modified L-shaped bandstop filter for UWB applications

Performance of UWB system may be degraded since the interference may be exist due to the presence of signals from other existing wireless communication systems. Currently, the major interference are in-band signal from 802.11a WLAN system which occupies the 5-6 GHz spectrum and signals from 802.11b/g WLAN system covering 2.4-2.48 frequency band. This paper presents the design of a modified L-shaped resonator bandstop filter for UWB applications. The applicability of the proposed design method is demonstrated by a conventional 2.45 GHz L-shaped bandstop filter with -60 dB attenuation, which was extended to include a modified L-shaped resonator´s design and result discussion. Methods of increasing bandwidth such as changing L-resonator width and cascading of filters are presented. The filters have been simulated using ADS design software and implemented on FR4 substrate.