分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jingye Yan
Ji Wu
Leonid I. Gurvits
Lin Wu
Li Deng
Fei Zhao
Li Zhou
Ailan Lan
Wenjie Fan
Min Yi
Yang Yang
Zhen Yang
Mingchuan Wei
Jinsheng Guo
Shi Qiu
Fan Wu
Chaoran Hu
Xuelei Chen
Hanna Rothkaehl
Marek Morawski
摘要： This paper introduces the first results of observations with the Ultra-Long-Wavelength (ULW) -- Low Frequency Interferometer and Spectrometer (LFIS) on board the selenocentric satellite Longjiang-2. We present a brief description of the satellite and focus on the LFIS payload. The in-orbit commissioning confirmed a reliable operational status of the instrumentation. We also present results of a transition observation, which offers unique measurements on several novel aspects. We estimate the RFI suppression required for such a radio astronomy instrumentation at the Moon distances from Earth to be of the order of 80 dB. We analyse a method of separating Earth- and satellite-originated radio frequency interference (RFI). It is found that the RFI level at frequencies lower than a few MHz is smaller than the receiver noise floor.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jingye Yan
Ji Wu
Leonid I. Gurvits
Lin Wu
Li Deng
Fei Zhao
Li Zhou
Ailan Lan
Wenjie Fan
Min Yi
Yang Yang
Zhen Yang
Mingchuan Wei
Jinsheng Guo
Shi Qiu
Fan Wu
Chaoran Hu
Xuelei Chen
Hanna Rothkaehl
Marek Morawski
摘要： This paper introduces the first results of observations with the Ultra-Long-Wavelength (ULW) -- Low Frequency Interferometer and Spectrometer (LFIS) on board the selenocentric satellite Longjiang-2. We present a brief description of the satellite and focus on the LFIS payload. The in-orbit commissioning confirmed a reliable operational status of the instrumentation. We also present results of a transition observation, which offers unique measurements on several novel aspects. We estimate the RFI suppression required for such a radio astronomy instrumentation at the Moon distances from Earth to be of the order of 80 dB. We analyse a method of separating Earth- and satellite-originated radio frequency interference (RFI). It is found that the RFI level at frequencies lower than a few MHz is smaller than the receiver noise floor.
分类： 地球科学 >> 空间物理学 提交时间： 2017-03-10
摘要： A single-layer broadband reflectarray antenna with four-arm spiral elements is presented. Large range reflection phase has been obtained by varying the length of the arms. The effects of different incident angles on the four-arm element are studied first. Then, a 441-element offset-fed linearly polarized reflectarray is fabricated and measured. The measured results agree well with the simulated results. Measured results show the gain level of 28.35 dB with 1-dB gain bandwidth of 28.7% (12.41-16.31 GHz) and aperture efficiency of 60.2% at center frequency of 13.58 GHz.
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