Broadband Planar SIW Cavity-Backed Slot Antennas Aided by Unbalanced Shorting Vias

摘要

Two types of substrate integrated waveguide (SIW) cavity-backed slot (CBS) antennas are proposed for bandwidth enhancement. First, a quad-resonance SIW CBS antenna is proposed using a cross-shaped slot and loading unbalanced shorting vias. Additional half-TE120 mode is successfully excited along with three other independent modes including half-TE110 and odd and even TE210 modes. Next, a penta-resonance SIW CBS antenna with a cross-shaped slot is proposed, in which two pairs of shorting vias are loaded. Two additional hybrid modes of half-TE210 and half-TE120 modes are introduced along with three other independent modes including half-TE110 and odd and even TE310 modes. Furthermore, the working mechanism of these two types of SIW CBS antennas is explained. Finally, prototypes of these two antennas are fabricated and measured at X-band. Their measured fractional bandwidths are 20.0% and 20.8%, respectively. Simulation and measurement results agree very well, which confirms the validity of the proposed designs.