Design and Analysis of a Bandpass Filter Using Dual Composite Right/Left Handed (D-CRLH) Transmission Line Showing Bandwidth Enhancement

A compact, low-profile, Band Pass Filter (BPF) based on balanced Dual Composite Right/Left Handed (D-CRLH) Transmission Line (TL) is proposed in this article. A balanced D-CRLH TL can be used to provide wideband filter characteristics due to no frequency separation between the RH and LH frequency bands. The proposed D-CRLH TL is designed using U-shaped complementary split-ring resonator (UCSRR). The extraction of equivalent circuit model of the proposed structure is also performed. The proposed filter provides a 3 dB passband range from 2.44 to 5.58 GHz. Further, the bandwidth is enhanced by introducing a slot in UCSRR, which resulted in a 3 dB passband range from 1.43 to 5.56 GHz. The proposed via less BPF has a compact size of 15 x 15 mm(2) designed on an FR-4 substrate with dielectric constant (epsilon(r)) = 4.3. The design analysis of the proposed bandpass filter is presented in terms of reflection coefficient, transmission coefficient, propagation constant and group delay.