Single-Layer Planar Waveguide Array Antenna With Low Sidelobe

A single-layer planar waveguide array antenna with low sidelobe levels is proposed in this paper. The proposed array antenna integrates radiating elements and the hollow E-plane waveguide feeding network in a single-layer structure, which reduces the assembly difficulty of waveguide array antenna. A series of unequal power dividers with adjustable power ratios are designed by cutting a triangle prism on the waveguide transmission line and they are applied to the single-layer planar waveguide feed network so as to achieve the desired power allocation for Taylor distribution. Actually, the sidelobe of proposed antenna could be controlled by the power ratios, which are determined by the size and position of the triangle prism. The simulated results show that the E-plane and H-plane sidelobe levels are below -25 and -22 dB respectively, within the working frequency band from 55 to 68 GHz.