24 GHz Circular Cavity-backed Slot Antenna Based on Corrugated Substrate Integrated Waveguides

Abstract

A novel low-profile circular cavity-backed slot antenna based on corrugated substrate integrated waveguide (CSIW) operating at 24 GHz is introduced in this paper. By replacing the conventional metallic via-holes in a substrate integrated waveguide (SIW) with quarter-wave open-stubs, CSIW not only preserves some advantages of the SIW technology, but also makes it easier to fabricate and integrate. We design a circular cavity on the basis of CSIW technology and realize the impedance matching by etching two split round slots with the same center on the top of the cavity. In addition, by changing the angle difference between the two splits, a new mode can be crated to widen the impedance bandwidth. Simulation results show the −10 dB impedance bandwidth of the proposed antenna is 6.6% (23.6–25.2 GHz), and the gain patterns are stable in the operating bandwidth and a maximum gain of 5.1 dBi can be achieved in the directions of θ = ±45°.