Development of the SIW horn antenna with partially detached broad-walls

In this paper, a novel substrate integrated waveguide (SIW) horn antenna with detached broad-walls is designed and analyzed. The detachment of the broad walls makes the field transition from TE₁₀ mode in the SIW to surface wave mode in the substrate without metal walls and thus significantly improves the impedance matching. Moreover, the substrate with graded dielectric constants is realized through perforating air vias with different diameters to further improve the radiation performance. Simulated results indicate that the proposed antenna operates from 17 GHz to 27 GHz with minimum 8 dBi gain. Stable endflre radiation patterns can be realized in the whole operating band.