SIW Cavity-Backed Antenna Array Based on Double Slots for mmWave Communications

This paper presents a cavity-backed antenna array in substrate integrated waveguide (SIW) technology in the millimeter-wave frequency band. The proposed antenna design uses double slots as radiating elements instead of conventional single slots. The double slots allow better control in the design of the operating frequency bands of the cavity-backed antenna. The performance of the cavity-backed antennas with single and double slots is compared to assess the enhanced behavior of the double slots. As a proof of concept, a 2 x 2 array of cavity-backed antennas is designed, manufactured, and measured. Each cavity-backed antenna contains 2 x 2 double slots; thus, a 4 x 4 antenna array is considered. The experimental operating frequency band of the proposed antenna array ranges from 35.4 to 37 GHz. There is a good agreement between the simulated and measured results. The measured gain is around 17 dBi in the whole operating frequency band with a 75% total antenna efficiency.