Design of UWB Bandpass Filter with Notched Band Using Distributed CRLH Transmission Lines

Abstract

This study presents an Ultra-Wideband (UWB) filter with a notched band. The filter adopts novel Composite Right/Left-Handed (CRLH) Transmission Lines (TLs), the unit cell of which is theoretically analyzed to derive the design formulas. A model of the CRLH TLs is composed with distributed elements rather than lumped elements. Based on the results of the analysis, it is confirmed that the proposed structures are CRLH TLs. A UWB bandpass filter with a notched band is designed and fabricated using the induced formulas. The measurement results show that the fabricated UWB bandpass filter has an insertion loss of less than 3 dB, a bandwidth of 2.8-10.5 GHz and a rejection of greater than 27 dB at 5.75 GHz.