A Study On High Isolation RF MEMS Switch

Microelectromechanical system (MEMS) technology has been developing for about two decades. It has been integrated into many existing designs, including radio frequency (RF) microswitches. As early as 1971, when the first RF switches were built using commercial technologies, its designs have developed and improved dramatically. Recently, RF microelectromechanical system switches have been envisaged to be perfect devices for such a wide range of commercial and military communication applications with portable sizes and wide-band reconfigurability owing to their outstanding performance such as high linearity, high quality factor, low loss, and low power consumption. The newest switches that are fabricated and tested today, using MEMS technology, operate at radio, even microwave frequency. An optimal RF MEMS switch is one with high isolation and operational life of millions of cycles. This work of the thesis is aimed at developing a switch with near optimal performance.Details regarding the design of RF MEMS switches for improving isolation and reliability are addressed. In addition, detailed processing techniques and fabrication concerning RF MEMS switches are investigated.The performance of this thesis is as following:Chapter 1, The switch parameters, classification, typical fabrication , performances and design considerations are introduced.Chapter 2, A new type of high isolation metal to metal contact switch with cantilever beam is presented. The relation between the pull-down voltage for the switches actuation and the curve of the cantilever beam is simulated. The natural frequency and stress distribution of some micro-switches with different structures are also analyzed.Chapter 3, Fabrication and process designs of the metal to metal contact series RF MEMS switches with diaphragm structure and electrodes fixed in the substrate are developed and discussed. Various process and fabrication design issues are also addressed in this chapter. Chapter 4, The contribution from this research is discussed and some suggestions for the future research are presented.