Investigation of Ultra-wideband Ridged Half-Mode Substrate-Integrated Waveguide Coupler

In this paper, a novel ultra wideband (UWB) 3-dB coupler at X and Ku band based on ridged half-mode substrate integrated waveguide (RHMSIW) and embedded the shape of metal groove is designed, fabricated, and measured, which is widely used in microwave and millimeter wave circuits. The structural parameters of new UWB RHMSIW 3-dB coupler with three cascading metal groove cells are analyzed. The structure is simulated with a relative bandwidth of 48% at the center frequency of 15 GHz. The measured results show that the proposed RHMSIW coupler keeps good performance of the HMSIW coupler. Simulated results are in agreement with the measured results. The results show that the novel UWB RHMSIW 3-dB coupler can provide better performance and have a smaller size compared with reported couplers, which illustrates its application in the wideband millimeter wave systems.