New Type Of Rf Mems Switch Circuit Design, Modeling And Applications

With the help of the advanced fabrication technology, the rapid development of RF MEMS technology has excited the developing tendency of miniaturization and integration for the RF/microwave circuits. Switch is of the important components in RF circuits, its high isolation, low insertion loss and miniaturization are the key points for its further development in the near future. The market will definitely grow with the improvement of switch lifetime.One kind of series ohmic MEMS switch has been designed and investigated in this work. The simulation results have indicated that the insertion loss is less than 1dB; the isolation is more than 20dB from 0 to 50GHz. The actuated voltage is 27.3V through electro-mechanical coupling analysis in ANSYS. In order to get lower actuated voltage, the length of the beam is increased and two electrodes are put under the beam, the actuated voltage is thus decreased to 11.8V. In addition, an ultra-wideband shunt ohmic switch is designed and investigated; its insertion loss is less than 0.7dB while isolation is more than 15dB. Furthermore, the equivalent circuits of the two kinds of switches are developed, and the formulas of discrete components are given. Good agreement can be observed between the results of equivalent circuit and structure simulation results.RF MEMS switch can be used as an independent component, and can also be used to form a switch array. The SPDT, DPDT and SP4T switch arrays have been designed, as well as a 4-bit phase shifter in 20GHz, which can provide 22.5,45,90 and 180 degrees respectively.