Reply to the Comments on “Super-Compact Substrate Integrated Waveguide Cruciform Directional Coupler”

For original paper see ibid., vol.17, no.5, p.757-9, (2007). For comment see ibid., p.374, (2008). Our proposed coupler was developed and designed on the basis of an idea similar to the H-plane crossed-waveguide hybrid. In our design, the standard metallic waveguide scheme was replaced by the substrate integrated waveguide (SIW) technology. This technology offers a number of advantages that can overcome several constraints with respect to the standard waveguide technique. A small inventory of coupler structures with the use of standard waveguide techniques was enumerated together with the existing SIW couplers. By properly choosing a dielectric constant and a sheet thickness, a directional coupler can be designed for a given frequency.