Improvement of Radiation Pattern Roundness of Patch Antennas for Radar Sensors

A patch antenna with enhanced pattern roundness achieved through ground slot loading is proposed. By incorporating radiation from the slots, the pattern roundness is significantly improved. This paper discusses the principle behind the slots' effect on the antenna pattern and examines the impact of slots of varying sizes on the improvement of roundness. Measured results demonstrate that the roundness of the antenna radiation pattern is improved by 5.5 dB within the operating band of the microwave radar sensor.