Measurement of the Sensitivity of Electromagnetic Environment Monitoring System at the Primordial Gravitational Wave Site

A 100 MHz to 20 GHz broadband electromagnetic environment monitoring system is developed for the application requirements of electromagnetic environment monitoring at Ali plan original gravitational wave site in this paper. In order to improve the sensitivity of the monitoring system, components such as rotary motors, radio frequency rotary joints, radio frequency switches, and low noise amplifiers are optimally designed and integrated to form an automatic rotation controller with low loss and low noise. Two methods of over-the-air direct test and conduction indirect test are used to verify the sensitivity of the monitoring system. Theoretical analysis shows that the sensitivity of the monitoring system mainly depends on the receiver noise floor level and the receiving antenna coefficient. According to the two test methods proposed in this paper, the sensitivity of the system is obtained, and the consistency of the over-the-air direct test method and the conduction indirect test method is confirmed.