| With the rapid development of today’s aerospace technology, the electromagnetic environment spacecraft working environment are becoming increasingly complex, there occurs a variety of electromagnetic interferences. The signal modulation recognition of electromagnetic interference under complex electromagnetic environment has become an important research topic. To monitor the working electromagnetic environment of spacecraft, we must rely on advanced monitoring and signal acquisition means to provide strong technical support.In this paper, the main work is to study the electromagnetic data acquisition system design under complex electromagnetic environment. Firstly, according to the project requirements, the software part of the acquisition system is designed, and then in view of the application in the industry, and medical band electromagnetic interference that working in the2.4GHz and UWB frequency band, the bionic structure antennas for data acquisition system are designed. In the study, with the use of the equipments like oscilloscope, spectrum analyzer, broadband detection receiver and antenna, a detection and positioning locale platform under complex environment of electromagnetic compatibility interference is designed and built. By feature matching and database comparing technology, the interference signal detection and modulation mode recognition and interference sources positioning are completed within the scope of50MHZ-16GHZ frequencies. The main work includes the following aspects:1. Introduces the design background and principle of the electromagnetic data acquisition system, which including a brief introduction of data acquisition equipment about ESMD signal receiver and its working principle, and signal recognition algorithms. According to the design scheme of the data acquisition system, the software design principles, realizing ideas and its implementation of the signal acquisition system are highlighting expatiated. According to the actual needs of the application, visual C++6.0platform is used to develop a windows-based interactive software systems for the control of electromagnetic data acquisition system.2. The antennas of signal acquisition system were studied, including the comparison and analysis of different shape microstrip antennas working at2.4GHz, and the performance index of the antenna were discussed. According to the simulation results, the performance of rectangular patch antenna and the inverted-F antenna is better than that of the basic circular patch antenna, while the size of the inverted-F antenna is reduced about a half compared to the rectangular patch antenna.3. Based on the study of traditional microstrip antenna, combined with bionics ideas, a new bionic butterfly like antenna is inquired, and the analysis of its electromagnetic characteristics is given. This paper presents a new butterfly-shaped slot antenna, and its performance is compared with the conventional antenna with simulation results. This paper utilizes metamaterials to load the butterfly antenna at the top of the structure, and the performance of the antenna is improved. The simulation results showed that, by loading "Gong" metamaterials at the top of the antenna butterfly, it can effectively narrow the main lobe width of the antenna, and enhance it radiation directional.4. By the simulation optimization through finite difference time domain method, a new type of tree like bionic antenna in ultra-wideband is designed and fabricated. The antenna size is12x10only, and it can be realized within the standing ratio less than2in scope of the3.1-10.6GHz ultra-wideband. And it also has the properties of omnidirectional radiation pattern, flat gain and linear phase. The basic performance parameters of the antenna are validated by testing result. At last, the tree like bionic antenna is used on the electromagnetic data acquisition system, which verifies the monitoring performance of the electromagnetic interference. |
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