Design process for dual coplanar waveguide directional couplers for power transmission

In this paper, a design process for power directional couplers using dual conductor-backed coplanar waveguides (CBCPW), is presented. The proposed methodology is applied to the design of a 50 Ω impedance coupler with 10 dB coupling factor for a central frequency of 2.5 GHz. The resulting coupler is validated through simulation by obtaining its dispersion parameters using ANSYS High Frequency Structure Simulator (HFSS). From the analysis of the return loss, insertion loss and coupling factor, in a range of 1 to 4 GHz, it was found that the coupling factor complies with the design specification for frequencies from 2 to 3 GHz, with insertion losses between -1 and -2 dB around the center frequency and return losses of -15 dB.