Radio frequency (RF) microelectromechanical systems (MEMS) switches are extensively used in wireless communication, radars and satellites due to their low power consumption, high isolation, small size and weight. The performance of RF MEMS switches are better than solid state switches in terms of power consumption, isolation, insertion loss and linearity. RF MEMS ohmic series and capacitive shunt switches working on the principle of resonance are the most common.

In the first half of this presentation, we will discuss the working of DOM and metal-insulator-metal (MIM) shunt capacitive switches and their limitations. The dependence of resonant frequency on various parameters such as thickness of dielectric, overlap area of beam over dielectric and inductance of the beam will be addressed. We further discuss a method to obtain high isolation for a wideband RF MEMS switch using the concept of floating metal in a MIM capacitive shunt switch.

In the second half, we discuss the working of high breakdown voltage bump on beam (BOB) cantilever beams and switches based on cantilevers. We further discuss the advantages of removing dielectric layer from the switch as any presence of dielectric may cause series dielectric issues and may lead to permanent failure of the RF MEMS switch. We discuss design, simulation, fabrication and characterization of cantilever-based dielectric-less SPST and SPDT RF MEMS ohmic switches. Both SPST and SPDT switches are designed using only cantilevers as the beam structure.