A 3D All-Metal Antenna Array for Millimeter-Wave Automotive Radar Applications

An all-metal cavity antenna based on waveguide transmission line theory is proposed for millimeter (mm)-wave automotive radar applications. A four-element waveguide cavity leaky-wave array antenna is proposed for 77 GHz radar application. The antenna is composed of three metal layers, namely, the four-element open waveguide, the jagged cavity and the hollow waveguide transmission line. The jagged cavity mainly operates in its TE104 mode. By adjusting the concave and convex structure of the jagged cavity structure, the antenna achieves a low sidelobe and impedance matching. The measured result shows that the proposed antenna displays a wide operation bandwidth from 75 GHz to 79 GHz. The peak gain is 11 dBi and the side lobe level is -16 dB.