Low Sidelobe Level Pattern Synthesis of 2-D Slot Array Antenna Based on Ridged Waveguide

Abstract

Slotted waveguide antennas have received much attention due to features such as low loss, high efficiency, and high power capacity. In this article, a 2-D slot array antenna based on a ridged waveguide with a low level of side lobe is synthesized. The antenna consists of four slotted ridged waveguides, each of which consists of eight slots as the radiating elements. A fast and easy way is proposed to synthesize the aperture distribution in the H-plane. Further, a corporate feed network based on ridged waveguide is designed to feed the antenna. The feed network is designed such that the desired aperture distribution in the E-plane is achieved. A prototype of the antenna is fabricated and measured. The measured sidelobe levels in the H- and E-planes are, respectively, -24.5 dB and -23.9 dB, and the reflection coefficient of the antenna is -19 dB at the design frequency, indicating the accuracy of the design procedure. The measured antenna gain is approximately 20.4 dBi at the entire frequency band. The stable radiation pattern of the antenna makes the antenna suitable for radar applications.