Bandwidth Enhancement of SIW Horn Antenna Loaded With Air-Via Perforated Dielectric Slab

A substrate integrated waveguide (SIW) horn antenna loaded with air-via perforated dielectric slab for bandwidth enhancement is proposed in this letter. The narrow impedance bandwidth of the planar horn antenna is mainly resulting from the discontinuity between the substrate and air. By simply drilling air-vias with different diameters in the substrate extended from the horn aperture, a smooth transition from substrate to air can be achieved, which can enhance the impedance bandwidth of the antenna in much degree. Measured results show that the enhanced impedance bandwidth of 40% from 16 to 24 GHz is obtained with the return loss |S₁₁| below -10 dB. In addition, stable radiation patterns are observed over the entire operating band.