A Dual-Band Rat-Race Coupler for High Band Ratio Wireless Applications
Aijaz M. Zaidi, Mirza Tariq Beg, Binod Kumar Kanaujia, Karun Rawat, Sachin Kumar, Karumudi Rambabu, Satya P. Singh, A. Lay-Ekuakille
Abstract
This paper presents a dual-band rat-race coupler for high band ratio wireless applications. In this paper, a dual-band transmission line has also been proposed to design the rat-race coupler. The proposed rat-race coupler has been developed by substituting each transmission line segment of a single-band rat-race coupler with the dual-band transmission line. To validate the design method, a rat-race coupler for 0.7 GHz and 4.9 GHz operating frequencies. has been developed. Maximum 3.3 dB insertion loss and 20 dB return loss and isolation have been attained for both the frequency bands. Compared with the existing dual-band rat-race couplers, the proposed coupler offers dual-band operation with a high band ratio. In addition, the first time a dual-band rat-race coupler compatible with to microstrip transmission line and having input and output on different sides has been developed. This feature makes simpler connections when connected to other circuits.