A Broadband patch and SIW cavity hybrid antenna for Millimeter-Wave Applications

In this paper, a hybrid antenna using a circular patch and substrate integrated waveguide (SIW) cavity is presented with a low profile and broadband characteristics. The proposed antenna is a compact single-layer structure with a height of 0.028 wavelengths in free space and consists of a SIW cavity with a circular slot and a circular patch radiator placed in the center of the cavity. The resonant mode of the SIW cavity is TE-210, due to the electromagnetic coupling effect, the resonant mode (TM-110) of the circular patch radiator is excited by the SIW cavity. The embedded microstrip lines are used in this excitation structure, enabling planar integration capabilities. The proposed structure is fabricated on a single-layer substrate using a printed circuit board (PCB), designed and simulated. It is shown that broadband impedance bandwidth of 6.5% and a maximum gain of 6.85 dBi is obtained for the hybrid antenna. The proposed antenna has the advantages of high gain, small form factor, simple structure, and low cost, which makes it attractive for practical applications.