Frequency-Scanning Waveguide Antenna for Solar Radio Bursts Detection in the UHF Band

This paper proposes a frequency-scanning antenna designed to operate in the 400 MHz to 800 MHz band for solar radio astronomy applications. It is constructed with perforated metallic walls and cylinders, that form a rectangular leaky waveguide. By adjusting the metallic cylinders in the appropriate subwavelength holes, the scanning angle of the directive beams and directivity can be effectively controlled while assuring high radiation efficiency and gain. Unlike previous leaky waveguides, the proposed design allows manual tuning of both the leaky-mode phase and the leakage factors. A 2-meter-long antenna prototype has been fabricated, and the measurement results show an angular scanning range from 70∘ to 30∘ above the horizon, with a peak gain of 14 dBi and radiation efficiency exceeding 70% over the entire scanning band. The application of this antenna to detect solar radio bursts without the need for Sun tracking is demonstrated.