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VLBI测轨的S/X致冷接收机技术

S/X Cryogenic Receiver Technology for VLBI Satellite Tracking

  • 摘要: 高灵敏度致冷接收机是提升我国探月工程VLBI测轨精度的关键设备。我国自主研发的S/X致冷接收机采用了双频馈源网络、致冷极化器、HEMT(High Electron Mobility Transistor)致冷低噪声放大器、超导滤波器等核心技术,实现了S/X双频信号的同时同目标高灵敏度接收。介绍了接收机系统设计及分部件研制情况,并对接收机噪声和系统噪声进行了实测。结果表明,S波段接收机频带2.19~2.3 GHz,接收机噪声温度8 K,天顶方向系统噪声温度53 K,X波段接收机频带8.2~9.0 GHz,接收机噪声温度13 K,天顶方向系统噪声温度32 K,很好地完成了我国探月工程VLBI测轨任务。

     

    Abstract: The high sensitivity cryogenic receiver is the important equipment to improve the measurement accuracy of the satellite tracking for Chinese Lunar Exploration Project. The low noise amplifiers of front end are cooled to 15 Kelvin. The equivalent noise temperature of cryogenic receiver is one order of magnitude lower than the traditional equipment working at room temperature, greatly improving the sensitivity of radio telescope. Several advanced technologies have been adopted to simultaneously realize highly sensitive dual-band observations on the same target, including S/X dual-band feed horn, cryogenic low noise amplifier based on HEMT, cryogenic polarizer and low temperature superconducting filter. The measured receive noise of S-band is 8 K in the frequency range 2.19~2.3 GHz, and the system noise is 53 K at zenith. The measured receiver noise of X-band is 13 K in the frequency range 8.2~9.0 GHz, and the system noise temperature is 32 K at zenith. The S/X cryogenic receivers have been applied successfully for VLBI satellite tracking in Chinese Lunar Exploration Project.

     

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