Introduction

Radio frequency microelectromechanical systems (RF MEMS) can offer unsurpassed RF performance over more conventional solid-state electronic devices and can help to implement advancements within a broad range of applications; from ubiquitous smart sensor networks to mobile handsets. Moreover, they can substantially reduce the size, weight and cost of reconfigurable subsystems; making this an important enabling technology for the twenty-first century.

MEMS technologies are already firmly established within high-volume commercial markets. Examples include inertial sensors/accelerometers (e.g. used in car airbag sensors, gaming accessories and mobile handsets), disk drive read/write heads, ink-jet printer nozzles, microphones and digital light projectors. In contrast, MEMS for RF applications has been relatively slow to move out of the laboratory and into commercial products. Indeed, the first RF MEMS papers started to appear over three decades ago. For example, a truly landmark paper was published on electrostatically actuated cantilever-type ohmic contact switches back in 1979 [1]. Over the past decade, however, a raft of interesting components and circuits has been demonstrated. Some of these developments have been reviewed from the perspective of enabling technologies [2], while the real founding principles have been described in some detail within the established textbooks by Santos [3], Rebeiz [4] and Varadan et al. [5]. More recent articles of noteworthy merit have also appeared on technologies, testing, reliability and applications associated with general RF MEMS [6–8].