UWB bandpass filter with switchable notching band using multilayer LCP technology

This paper proposes a novel reconfigurable ultra wideband (UWB) bandpass filter with switchable notching band for ultra wideband communication systems. In this study, PIN diodes are used to switch the notching band and broadside coupling technique is adopted to design the notching resonator. A prototype of proposed filter has been designed with a 10 dB insertion loss bandwidth from 3.05 GHz to 10.65 GHz for FCC-Defined UWB Indoor Limit system. A switchable notching band located at 5.5 GHz is designed to reduce the interference from the existing 5.5 GHz wireless local area system. The designed filter has been fabricated by using the multilayer liquid crystal polymer (LCP) lamination process and measured using a Vector Network Analyzer. Both measured and simulated results are compared and presented with good agreements. The proposed filter has a compact size with simple DC bias circuit. It is attractive for the cognitive UWB systems.