A stiff and flat membrane operated DC contact type RF MEMS switch with low actuation voltage

RF MEMS switches can be divided into electrostatic, magnetic, thermal, and piezoelectric types by their actuation mechanisms. Most research has focused on the electrostatic actuation types because of these types low power consumption, simple fabrication method, and good RF characteristics. However, these types of switches operate at high voltages compared with the other types. One of the main problems that affect the operation voltages is the bending of the membrane due to an internal stress gradient. To solve this problem, a thick and stiff membrane operated RF MEMS switch has been developed and is presented in this paper. This membrane consists of a flexible spring for an up-down actuation mode at low voltage and a pivot under the membrane for a seesaw mode on-off switch operation. This novel RF MEMS switch has been fabricated, and its RF characteristics measured. The minimum actuation voltage is approximately 10-12 V, the isolation approximately -50 dB, and the insertion loss is approximately -0.25 dB at 2 GHz, respectively.The bending range of the membrane has been measured by using an optical 3D profiler and the height is within 0.2 μm across the 800 μm length membrane. This bending range is uniform across all samples of an entire 4 in. wafer.