Bandwidth improvement of substrate integrated waveguide cavity-backed slot antenna with dielectric resonators

In the paper, a low profile substrate integrated waveguide based circular-shaped cavity-backed antenna is delineated to work at WLAN U-NII mid band and a slender rectangular slot is then placed at its center on the ground plane for radiation. The parent antenna radiates at 5.33 GHz with a gain of 4.9 dBi; depicting a narrow impedance bandwidth of 50 MHz. The antenna is modified by placing dielectric resonators of different shapes over the slot to enhance the bandwidth. The new antennas thus produced have an impedance bandwidth of 750 MHz with cylindrical-shaped and rectangular-shaped dielectric resonators which reflect bandwidth enhancement of 700 MHz for both the cases and an impedance bandwidth of 710 MHz with hemispherical-shaped dielectric resonator reflecting bandwidth enhancement of 660 MHz. The gain of the modified antennas is of the order of 4.7 dBi which basically indicates not much degradation in gain as compared to the parent antenna. All the antennas are delineated using Arlon AD270 substrate material with the results obtained after simulation juxtaposed with the ones obtained through measurement.