Light Communication Device In Mems Rf Switches And Application

RF MEMS switches, the core device which can realize route-conversion in RF/microwave communication systems, become more and more attractive in the communication field nowadays, and have been a focus of the research in the world. RF MEMS switches have many advantages such as small size, low insertion loss, high isolation, excellent linearity, wide frequency and low power consumption. Therefore, RF MEMS switches get more and more application in the aerial light device.At first, the application of RF MEMS switches in our subject was analyzed. There are some specific requirements on RF MEMS switches: Si substrate must be used; RF MEMS switches should be manufactured by surface micromachining technology; the manufacture of RF MEMS switches can be compatible with the conventional IC machining and microelectronic circuit; RF MEMS switches can control the signal in the L/C/X bands and can be integrated into the manufacturing of array micro-strip antennas, so that the array micro-strip antennas can switch the working frequency among the three different bands. This is just one of the innovations in this article.By consulting plenty of literatures at home and abroad, we analyzed and compared the advantages and disadvantages of the inline MEMS-series cantilever beam switch, the broadside MEMS-series cantilever beam switch, the MEMS capacitive shunt switch, and some various actuation modes. According to the investigation of technological feasibility and specific requirements in our subject, the preliminary scheme of RF MEMS switch was determined as broadside MEMS-series cantilever beam switch of electrostatic actuation type. Then, we built the mechanics model and electromagnetic model of the switch in the preliminary scheme, and theoretically deduced the performance parameters of the RF MEMS switches, such as elastic coefficient, actuation voltage, switching time, capacitance in up state, inductance in down state, isolation, insertion loss. On the basis of the above analysis, the relationship between the structure parameters and the performance parameters of the switch was summarized. Besides, according to the design method of electromechanical coupling, we simulated the several switches which have different structure types by the software of ANSYS and Ansoft HFSS, to demonstrate the theoretical analysis and obtain the key structure size and the optimum materials in the design of RF MEMS switch. This is another innovation in this article.In the end, according to the research of manufacturing technology and machining technology of MEMS, the manufacturing process and the processing maps of the RF MEMS switch have been determined, and the switch is manufacturing in the Photoelectric Institute of Chinese Academy of Sciences in Chengdu.By the analysis and calculation, the elastic coefficient of the cantilever beam can get about 12 N/m; the mechanical restoring force of cantilever beam can get about 36μN; actuation voltage is about 35 V. At 1 GHz, the isolation of the RF MEMS switch is -46 dB; At 12 GHz, the isolation of the RF MEMS switch is -20 dB. The insertion loss of the RF MEMS switch could be -0.2 to -0.4 dB without the business of frequency almost.