A 50–55 GHz Millimeter-wave Radiometer Spectrometer for Solar Flare Detection

• Published in: The Astrophysical journal. Supplement series Vol. 279; no. 1; pp. 29 - 37
• Main Authors: Xu, XiaoFeng, Zhao, ZhanFeng, Liu, Qian, Li, QinZheng, Wu, Zhao, Lu, Guang, Su, YanRui, Chen, Yao, Yan, FaBao
• Format: Journal Article
• Language: English
• Published: Saskatoon The American Astronomical Society 01.07.2025; IOP Publishing
• Subjects: Analog to digital conversion; Cassegrain antennas; Circular polarization; High energy electrons; Magnetic fields; Millimeter waves; Performance measurement; Radiation; Radio bursts; Radiometers; Solar activity; Solar flares; Solar physics; Solar radiation; Solar radio flares; Solar radio telescopes
• ISSN: 0067-0049; 1538-4365
• DOI: 10.3847/1538-4365/ade0b5

During solar flare eruptions, millimeter-wave radiation is emitted, which is highly efficient and sensitive to high-energy electrons, allowing for the extraction of unique magnetic field information. Therefore, we have developed a 50–55 GHz solar millimeter-wave radiometer system. The system employs a 50 cm diameter Cassegrain antenna to receive circularly polarized solar radiation signals. These signals enter the analog front-end system, where they undergo power division, filtering, and detection operations, resulting in voltage signals. Subsequently, the signals are processed by the digital receiver for analog-to-digital conversion and smoothing and are finally transmitted to the host computer via the RS422 protocol to display the intensity of solar radiation. The system’s performance metrics are as follows: a noise figure of <2.5 dB, system linearity ≥0.9999, a time resolution range of 0.001–1 s, and a dynamic range exceeding 30 dB. The system began routine observations in 2024 October and successfully captured the world’s first 50 GHz band solar flare data in December. Currently, the system is effectively observing during the 25th solar activity maximum period, which is expected to provide valuable data for solar physics research.