Ridge Substrate Integrated Waveguide (RSIW) Dual-Band Hybrid Ring Coupler

A novel dual-band ring coupler is proposed in Ridge Substrate Integrated Waveguide (RSIW) technology. The structure is based on two concentric rings with the outer ring loaded by a low insertion loss de-multiplexing scheme allowing independent dual band operation. The RSIW ensures a wide-band fundamental mode operation covering both frequency bands while providing a compact design. A C/K band coupler is experimentally verified showing coupling bandwidths of 6.9% and 14.6% centered at 7.25 and 20.5 GHz, respectively.