Electromechanical Properties Research Of The RF MEMS Switch

With the development of the wireless communication, the requirements of miniaturization, power consumption, performance in RF device are increasing. RF MEMS switches with its small size, low power consumption, high isolation and low insertion loss has the potential to replace the traditional switches like PIN switch and FET switch. It has wide applications in the field of wireless communication, such as in Phase shifter, Phased array ladar and satellite navigation.This article analyzes and tests the electromechanical and the radio-frequency performance of the MEMS switch under different experiment condition. This research analyzed the reliability of DC contact switch and designed a system of testing the reliability in the MEMS switch. Besides, it designed contact switch which has Multi-layer clamped beam structure. The Switch is manufactured and tested. The main content of the thesis are as follows:1.The electromechanical characteristics of DC contact switch is analyzed. The elastic coefficient, the driving voltage and the switching speed are deduced. The relationship between the driving voltage and the contact resistance is tested. The electromagnetic model of contact shunt RF MEMS switch is established. The computational formula of insertion loss and isolation is deduced and tested based on the model. The test analyzed the relationship between the driving voltage and S parameters of the switch.2.The influence of contact resistance and power on reliability of the DC contact switch is analyzed. The system of testing the reliability of the RF MEMS switch is designed. Through the testing system, the lifetime test is done and the contact damage is verified. Besides, the influence of high-power on switched transmission is verified.3.Contact switch which has Multi-layer clamped beam structure is designed. The structure parameters of the switch are determined through the simulation of the electromechanical and radio-frequency performance. The research simulated and analyzed the influence of beam’s opening on the driving voltage and the influence of the structure on the reliability of the switch. The result of the simulation testified that the insertion loss less than-0.26 dB, return loss less than-21.5dB,isolation less than-26 dB when the frequency range between 2~30GHz. The switch time is μs21 when thedriving voltage is 40V; The switch is taped out using surface-micro machining technology. The improvement method is proposed and the invalid principle is analyzed after the DC test.