Wideband Directional Coupler for X-band using SIW Technique

Abstract

In this article, compact and wideband directional coupler has been proposed based on substrate integrated waveguide technique for X-band applications. The bandwidth of directional coupler has enlarged by tapering the coupling section. This coupler consists of two narrow apertures on the common broadside wall of two adjacent SIWs and four microstrips to waveguide transition line. Attractive features including compact size and planar form make this coupler structure easily integrated in antenna beam-forming networks. The coupling is about 7 dB at 9 GHz to 12 GHz frequency, the isolation is below 15dB over the frequency range of 9-12 GHz, and the return loss is better than 15dB. Design considerations and results are discussed and presented. A simulation has been carried out by Ansoft High frequency structure simulator (HFSS).