A Broadband Solar Radio Dynamic Spectrometer Working in the Millimeter-wave Band
A Broadband Solar Radio Dynamic Spectrometer Working in the Millimeter-wave Band
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毫米波波段宽带太阳射电动态光谱仪
DOI：
10.3847/1538-4365/ac4257
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发表时间：
2022-02-01
影响因子：
8.7
通讯作者：
Yan, FaBao
中科院分区：
文献类型：
--
作者：
Shang, ZiQian;Xu, Ke;Yan, FaBao
大多数太阳射电望远镜工作在18 GHz以下，不能实现微波频谱的完全频率覆盖，特别是在太阳爆发期间的光学薄区，这可以提供关于日冕爆发区域磁场的独特信息。因此，发展高频微波观测设备是太阳能射电界的需要。本文介绍了一种工作在35-40 GHz的微波光谱观测系统。在该系统中，太阳无线电信号由80 cm卡塞格伦圆极化天线捕获，然后由35-40 GHz模拟前端进行下变频和信道化。最后将处理后的信号送入数字接收机，生成微波动态频谱，再通过千兆以太网传输至上位机。系统性能测试结果如下：噪声系数接近300K，系统线性度为>；0.9999，时间分辨率约为134ms(默认)，频率分辨率为153kHz。我们进一步对该系统进行了定标，发现在新月期间观测到的日月比约为43.1-53.3@35.25 GHz，与理论值非常接近。在9小时的测试中，该系统的变异系数接近0.61%。该系统已在茶山太阳天文台进行了一年多的设计、研制和试验，有望在第25太阳周的微波爆发研究中发挥重要作用。
Most solar radio telescopes operate below similar to 18 GHz and cannot realize a complete frequency coverage of the microwave spectrum, especially in the optically thin regime during solar bursts, which can provide unique information about the magnetic field in the burst area in the solar corona. Therefore, the development of high-frequency microwave observation equipment is demanded by the solar radio community. In this paper, we present a microwave spectrum observation system operating at 35-40 GHz. In this system, the solar radio signal is acquired by an 80 cm Cassegrain circularly polarized antenna, which is then downconverted and channelized by a 35-40 GHz analog front end. The processed signal is finally sent to the digital receiver to generate the microwave dynamic spectrum, which is transmitted by gigabit Ethernet transmission to a host computer. The system performance has been tested and obtained as follows: a noise figure of similar to 300 K, system linearity of >0.9999, time resolution of about 134 ms (default), and frequency resolution of 153 kHz. We further conduct calibration for this system and find that the observed Sun-Moon ratio is about 43.1-53.3 @ 35.25 GHz during the new Moon, and is quite close to the theoretical value. The coefficient of variation of the system is similar to 0.61% in a 9 hr test. The system has been designed, developed, and tested for over 1 yr in Chashan Solar Observatory and is expected to play an important role in the microwave burst study in the 25th solar cycle.