Design of Dual-Band Six-Port Rat-Race Coupler (RRC) Using Composite Right/Left-handed Transmission Lines (CRLH-TLs)

A miniaturized dual-band six-port rat-race coupler (RRC) is proposed using Composite Right/Left-handed Transmission Lines (CRLH-TLs). The phase response of this new six-port RRC at the designed two operating frequencies is 90°, 180°, 270°, respectively. Herein, an investigation is conducted into the impact of different cell numbers of CRLH-TLs, based on which the most suitable CRLH-TLs are determined to design a dual-band six-port RRC with operating frequencies of 0.6GHz and 1.1GHz. Finally, the simulation results are obtained to verify the design.