Introduction: RF MEMS for Microwave Applications

Abstract

THE BEGINNING OF RF MEMSMicroelectromechanical Systems (MEMS) have been developed since the 1970s for pressure and temperature sensors, accelerometers, gas chromatographs, and other sensor devices. MEMS switches for low-frequency applications have also been demonstrated in the early 1980s but remained a laboratory curiosity for a long time. They are essentially miniature devices that use a mechanical movement to achieve a short circuit or an open circuit in a transmission line. But in 1990But in -1991, under the support of DARPA (Defense Advanced Research Projects Agency), Dr. Larry Larson at the Hughes Research Labs in Malibu, California, developed the first MEMS switch (and varactor) that was specifically designed for microwave applications [1]. However, and as usual with any leap in technology, it was far from mature and had poor yield and virtually no reliability. Still, it demonstrated excellent performance up to 50 GHz, far better than anything that could be achieved with GaAs devices.The initial results of Larson were so outstanding that they stirred the interest of several groups in the U.S. government; and by 1995, Rockwell Science Center and Texas Instruments both had developed an outstanding RF MEMS switch. The Rockwell switch was a metal-to-metal contact type, suitable for DC-60 GHz applications, while the Texas Instruments switch was a capacitive contact switch, suitable for 10-120 GHz applications. The rest is history; by 1998, the University of Michigan, The University of California, Berkeley, Northeastern University, MIT Lincoln Labs, Columbia University, Analog Devices, Northrup Grumman, and several other companies were actively pursuing RF MEMS devices. By 2001, there were more than 30 companies work-

A Reconfigurable Pseudohairpin Filter Based on MEMS Switches

“…RF-MEMS are very useful for wireless sensors [36] and reconfigurable antennas [37]. RF-MEMS show very good performance in switching speed (usually ranging from fractions of µs [38] to 300 µs [39]), scattering parameters, and power consumption (aside from leakage currents in the order of dozens of µA, electrostatically actuated RF-MEMS switches present a virtually zero power consumption [40]), and they have been demonstrated to work properly up to 90 GHz [41].…”

Voltage and Deflection Amplification via Double Resonance Excitation in a Cantilever Microstructure

“…Microelectromechanical systems (MEMS) devices are considered as prime candidates for IoT sensors. Currently, MEMS devices are used as high-frequency switches [1,2], sensors [3,4,5,6,7,8], RF amplifiers [9], mirrors, [10], and oscillators [11,12,13]. These developments led to fabricate and integrate MEMS devices into silicon chips easily, and achieve the requirements of low power, low cost, and smaller weight.…”

MEMS variable capacitance devices utilizing the substrate: I. Novel devices with a customizable tuning range

“…Typically, TR is very high in switches, lower for the case of SC and even lower in the case of varactors. Rebeiz [2] summarizes a library for these passives.…”

“…Thus far, the literature reports structures that only deal with a specific type of these three latter devices at a time. Given a specific fabrication process, designers carry out theoretical calculations and/or simulations to try and anticipate and optimize the eventual fixed, single, value of TR [2]. This paper, the first in a series of two, on the other hand, presents novel structures capable of providing customizable TRs fabricated in the PolyMUMPS process [3] with the substrate utilized, for the first time, as an integral part of the design.…”