A Low Profile Improved Gain SIW-Based H-Plane Horn Antenna for X-Band Application

In this paper, a substrate integrated waveguide (SIW)-based H-plane horn antenna with enhanced gain made on a very thin substrate (0.009λ0) is proposed for X-band application. Improved impedance matching is obtained by implementing three stepped quarter-wave transformers in the feed section and four circular slots at the front of the horn. Two rows of teflon vias are used to enhance the gain, and the corrugated wall technique is also implemented to improve other antenna radiation characteristics. The measured fractional impedance bandwidth of 5.22%, the gain of 10.82 dBi, the radiation efficiency of 88.56%, the front-to-back ratio of ≈15 dB, and the low cross-polarization level have been achieved at 10.71 GHz.