Broadband Half Mode Substrate Integrated Waveguide Cruciform Coupler

In this paper, a cruciform coupler with half mode substrate integrated waveguide structure is presented. The prototype coupler consists of four half mode SIW structures crossing each other in right angle and two metallic posts are inserted in free section of junction in order to reach the coupling properties. Compact size and broadband operation are the features of this coupler. The size of coupler is reduced about 24% compared to previous HMSIW cruciform coupler and arround 40% smaller than the SIW cruciform coupler. a fractional bandwidth of about 35 percent is obtained. The coupler has been designed and simulated with HFSS13 and CST microwave studio for full wave simulation. Here, the simulation results have been compared with experimental results.