A Compact and High Gain SIW H-Plane Horn Antenna With Stepped Hard Boundary Condition

A compact and high gain substrate integrated waveguide (SIW) H-plane horn antenna loading stepped hard boundary condition is proposed in this paper, which is applied for the Ka-band. The proposed antenna is based on the traditional H-plane horn antenna, and by loading stepped hard boundary condition, the aperture efficiency and gain of the proposed antenna also can be improved. The stepped hard boundary condition is achieved by excavating the internal dielectric of the tapered horn. Three layers of the dielectrics are added in advance of the aperture to achieve better the impedance matching. The simulated result indicates that the proposed antenna has a wide bandwidth of 14.6% (from 31.1 to 36 GHz) and an average gain of 9.38dBi. Importantly, compared with the original antenna, the proposed antenna achieves an average gain improvement of 0.6 dBi from 31 to 34 GHz and 2 dBi from 34–36 GHz. Moreover, Under the same aperture conditions, the longitudinal length is shorter by 21.3% than the original antenna.