2$\,\times\,$ 2 Microstrip Patch Antenna Array Fed by Substrate Integrated Waveguide for Radar Applications

A 2 × 2 microstrip patch antenna array fed by a substrate integrated waveguide (SIW) feeding network for 24-GHz radar applications is proposed in this letter. The microstrip patches are aperture-coupled with the feeding network consisting of a perpendicular coax-to-SIW transition and two Y-junction power dividers. The antenna design is performed in the full-wave electromagnetic solver ANSYS HFSS and verified by measurement. At the operation frequency 24 GHz, a fabricated prototype has a gain of 11.1 dBi and a low sidelobe level below -22 dB in the E-plane and -33 dB in the H-plane.