A novel sensing gap reconfigurable capacitive type MEMS accelerometer with high sensitivity and high resolution is designed, fabricated and characterized. The present MEMS accelerometer is fabricated by using simple SOI process-DRIE. However, conventional Silicon on Insulator (SOI) process is hard to make patterns which is smaller than 1 um
because of its high aspect ratio and ICP etching error such as loading-effect and under-cutting. So we have adopted a
simple idea of the MEMS actuator-stopper system to modulate the sensing gap precisely. Unlike previous capacitive type
MEMS accelerometer which has an anchored reference comb electrodes, the proposed accelerometer has a movable reference comb with MEMS electrostatic actuators and stoppers. By simply applying DC bias to MEMS actuators, the reference comb electrode is moved to the sensing comb structure until the actuators contacting the stoppers. The gap between sensing comb fingers and reference comb fingers is reduced by the gap between actuators and stoppers. In this paper, the initial sensing gap is 1.5um and it reduced to 0.5um, when working. Then, the overall capacitance and sensitivity is simple increased. The capacitance is increased from 3.47pF at the OFF state to 5.35pF at the ON state by applying 2V DC bias.
Micromachined antennas have been fabricated on GaAs substrates with the thickness of 100 μm. The patch size of a half-wavelength rectangular-shaped antenna has been reduced about 63.8% by fabricating a folded slot antenna with shorting pins. A quarter-wavelength rectangular shaped antenna and the folded slot antenna on COB show the bandwidth of 300 <i>MHz</i> and <i>350 MHz, respectively and</i> the quarter wavelength antenna on a MLF package presents the bandwidth of 400 <i>MHz</i>. The bandwidth and antenna gain of the half-wavelength antenna, the quarter- wavelength rectangular shaped antenna, and the folded slot antenna have been measured on COB. For the MLF package, the quarter- wavelength rectangular shaped antenna has only been studied