A Simple Broadband Transition from Waveguide to Microstrip Line in X Band

A simple broadband transition from waveguide to microstrip using the short transformer technique is proposed and investigated in this paper. A layer of dielectric substrate is employed as a matching structure between the waveguide and microstrip line structure, which is optimised using the direct search method. It is shown that the transition has an average return loss value of -19.2 dB throughout the X band (8-12 GHz) with the best return loss value of -64 dB