A novel multilayer e-plane half-mode substrate integrated waveguide (HMSIW) 3-dB coupler with improved out-of-band rejection

摘要

A novel E-plane 3 dB directional coupler with enhanced out-of-band rejection has been proposed and developed in multilayer HMSIW topology. A continuous coupling slot is etched in the conductor layer at the broadwall of HMSIW. Periodic ginkgo leaf slots are etched on top layer of HMSIW to realize a pass-band combining with high-pass characteristics of HMSIW. Coupling takes place through the long, offset slot, which feature a flexible design providing a wide coupling dynamic range with wideband characteristics. Design process is introduced based on the even-odd mode theory. This technique provides a compact design through both the double layer scheme and the half-mode structure. Accordingly, more compact design has been achieved than H-plane HMSIW coupler. The novel coupler is showing a 20% coupling bandwidth at 10 GHz with good isolation, reflection and out-of-band rejection performances.