Improving the Performance of SIW-based Leaky Wave Antenna using the Creation of an Entrance Hole

In this paper, the effect of input holes on the performance of leaky wave antennas(LWA) is investigated by presenting two designs based on the substrate integrated waveguide(SIW) structure. Both antennas are made of unit cells with transverse and longitudinal slots, the main difference being the placement of holes in the input ports of one of the designs. The simulation, fabrication and measurement processes for both LWAs confirm findings. The antenna equipped with the hole in the input port achieves a bandwidth of 6.7 GHz with a minimum return loss of +10 dB over this entire bandwidth, focusing at a frequency of 12.8 GHz and a reflection coefficient of -48.5 dB. The antenna is capable of beam scanning from -66° to +5° and from +20° to +73° with a cross-polarization level of more than -45 dB over the entire frequency scan range. The final antenna has a maximum gain of 16.7 dB in the 7.9–14.6 GHz frequency band with 52% of the normalized bandwidth relative to the center frequency. Overall, the findings emphasize that the inclusion of input holes in LWA designs significantly enhances the antenna radiation performance and highlight their potential for optimizing SIW-based antennas in various applications.