Dual-Band SIW Cavity-Backed Slot Array Using TM020 and TM120 Modes for 5G Applications

In this communication, dual-band and low-profile circular cavity-backed slot array using TM 020 and TM 120 modes is proposed based on the substrate integrated waveguide for the fifth-generation (5G) applications. Two key issues are solved: multiresonance and proper frequency ratio. For the former one, the proximity-coupled slot is utilized to excite the high-order modes and depress the polarization degenerate modes. For the latter one, the TM 020 and TM 120 modes of the circular cavity are used to cover the 28/38 GHz bands. Finally, a cavity-backed slot array with excellent performance is achieved. The mechanism is discussed in this communication, and for demonstration, the prototype is fabricated and measured. The results show that the operating bands of 26.3-32.3 and 37.4-38.4 GHz are achieved, which cover the 28 and 38 GHz bands, respectively. The realized gains are 13.2 dBi at 28 GHz and 14.6 dBi at 38 GHz. The thickness of the array is 0.12\lambda , where \lambda is the wavelength at 28 GHz. The proposed array is eligible for the 5G applications in the Ka -band.