Slab Air-Filled Substrate Integrated Waveguide (SAFSIW) Cruciform Coupler

A 3-dB cruciform coupler based on slab air-filled substrate integrated waveguide (SAFSIW) is presented, analyzed, and demonstrated in Ka-band. Using the odd-even mode analysis, a design procedure is detailed to simplify the design process. The odd-even mode decomposition is shown to be in good agreement with the full structure simulation results. Measurement results confirm the operation of this cruciform coupler with an isolation level better than 15.7 dB over the entire Ka-band. The proposed coupler contributes to expanding the air-filled substrate integrated waveguide (AFSIW) component library.