Papers by Author: Zheng You

Abstract: With the development of the MEMS technology and the more widely-used micro-systems, micro-power devices are developed for portable consumer electronics. ^[ The MEMS supercapacitor is one of the most important parts for micro-powers. In this paper, a micro-supercapacitor was designed and fabricated with three-dimensional microelectrode arrays configuration. It has been tested by scanning electron microscopy, Cyclic Voltammeter, Galvanostatical charge/discharge curve and electrochemical impedance spectroscopy. These posts were 50 μm in diameter and 100 μm tall; with foot print area of 2×2mm². The capacitance is 89.52mF/cm². The biggest feature in this paper is that the two plates of the supercapacitor are both three-dimensional microelectrode arrays which are shown to offer significant advantages.

Abstract: A new isolation optimization method of radio frequency (RF) microelectromechanical systems (MEMS) capacitive switches is carried out in this paper. We simplified the coplanar waveguide and the top movable electrode as two-port network. The existence of the maximum isolation of single switch is proved theoretically based on circuit model and S-parameters model. The isolation of the distributed switches with lossless transfer lines, which is the function of the transfer lines length and the impedance of metal beams, is described by mathematic expressions and simulated in a numerical method. We find that the isolation varies periodically with θ and f, which are the electrical length between metal beams of the distributed switches and the signal frequency. It achieves the maximum value 83dB at θ=π/2 for 2-beams switch. However, different from single beam switches, the distributed switches maximum isolation is near but not precisely at the resonance frequency f0. The bandwidth of RF signal can be widened to about 200% for 5-beams switch by using the proposed design method. The results will be useful for Resistance-Inductance- Capacitance parameters optimization of RF MEMS Capacitive switches.