RF-MEMS devices

Much of the literature on modeling RF MEMS devices focuses on equivalent-circuit models, although the circuit values are often obtained by curve-fitting to measured RF performance. This is especially true for obtaining the s-parameters (for a discussion of s-parameters, see [14, 15]). These equivalent circuits, however, are... 

In addition to the term MEMS, categories like microoptoelectromechanical systems (MOEMS), radio-frequency MEMS (RF-MEMS), and MEMS for medical or biomedical application (BioMEMS) have been established. The market for microfabricated devices is still in its infancy and is growing with rates comparable to the first years of microelectronics. According to one market research report, the sales of microfabricated systems was 12 billion in 2004 and is expected to grow with a CAGR of 16% to 25 billion in 2009 [6]. Recent extensions of fields of application are consumer, entertainment, and homeland security. Upcoming new devices are MEMS microphones, microenergy sources, micropumps, chip coolers, and micromachined wafer probes, and this will definitely not be the end of new developments. 

Because the simulations use code-based, reduced-order models instead of FEM-based or BEM-based partial differential equation models, the simulation time is reduced by orders of magnitude. The compelling benefit of this new paradigm is twofold (1) designers can capture complete device and subsystem behavior across the different physics domains required for sensor, optical, and RF MEMS, and (2) accurate, comprehensive simulations take only minutes instead of days, enabling rapid exploration of wide-ranging design spaces. 

J.J. Yao, RF MEMS from a device perspective (topical review), J. Micromechanics Microengineering 10, 2000, R9-R38. 

There are more issues and complexity to be considered if various micro-electromechanical (MEMS)-type devices are included in the macroelectronics tool kit. As described previously, the materials and devices required for TFTs and circuits can provide adequate electromagnetic (visible and RF) sensitivity for many image-type applications. These materials may also provide satisfactory performance in pressure and strain sensors. Nanotube/nanowire-based devices look promising for various chem-bio sensors.85 However, there is little that is known about the ability to integrate printed microfluidic devices (and other such devices with moving parts) into a roll-to-roll-type process. 

Microelectromechanical systems (MEMS) combine the electronics of microchips with micromechanical features and microfluidics to create unique devices. The multitude of MEMS applications continues to grow including many types of accelerometers, radio frequency (RF) devices, variable capacitors, strain and pressure sensors, deformable micromirrors for image projection systems, vibrating micro-membranes for acoustic devices, ultrasound probes, micro-optical electromechanical systems (MOEMS) and MEMS gyroscopes, to name a few. 

Finally, in order to obtain the information collected by implanted sensor microchips, the data must be transmitted to the outside. Unfortunately, the salt-water environment of the body is quite attenuating to RF transmissions. However, RF transmission into and out of devices implanted within the body has been developed for RFID tags that are now commercially available. Furthermore, there is ongoing development in the area of RF and RF components on MEMS and microchips in general [45-48],... 

With the exception of a few analogue IC and power device manufacturers using 300 mm wafer technology, aU analogue and RF ICs, MEMS and MOEMS devices, mainstream power MOS and biochips are produced on smaller wafer sizes between 100 and 200 mm. In many cases, legacy tools, that is, refurbished More Moore CMP equipment, are used in the manufacturing lines. 

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