Design of Dual-Band and Low-Profile SIW Cavity-Backed Slot Antenna for 5G Applications

In this communication, the design of a dual-band and low-profile SIW cavity-backed slot antenna operating at K-band and Ka-band has been proposed to expand the Impedance bandwidth (IBW) of the antenna. The dual-band antenna consists of the SIW cavity with two parallel slots etched on the conductor's ground plane. To obtain a dual-band, higher-order hybrid modes are tuned and combined to form the second band of the proposed antenna with a broader bandwidth. For dual-band antenna, fractional bandwidth of 5.26% and 6.15% are attained with the maximum gain of 5.45 dBi and 6.15 dBi at 24.7 GHz and 27.8 GHz, respectively. A cavity-backed antenna using via-hole and the slot has been proposed to improve an IBW and other antenna performance parameters. Via-hole establishes a connection between the top and bottom surfaces of the cavity, creating a new path for the current to flow by shortening the slot's effective length. An IBW of 4.2 GHz (15.32%), where a gain of 7.8 dBi and 9.2 dBi have been realized at 25.9 GHz and 28.8 GHz, respectively. Isolation of less than 25 dB has been achieved through simulation. In terms of $\lambda_{0}$, the overall volumetric dimension of the proposed antenna is 1.68 $\lambda_{0}\times 1.31\lambda_{0}\times 0.04\lambda_{0}$. The proposed design demonstrates better performance in terms of antenna parameters, including compactness, good radiation characteristics, enhanced impedance bandwidth, and higher gain than the latest state of the art.