Diseño y Análisis de un Capacitor Variable MEMS utilizando Actuadores Térmicos
José Mireles Jr1., Humberto Ochoa2 and Víctor Hinostroza3
Instituto de Ingeniería y Tecnología de la Universidad Autónoma de Ciudad Juárez Ave. Del Charro 450 N., Ciudad Juárez Chihuahua, México. CP 32310 TEL. +52 656 6884800, x4571 e–mails: Josemireles@ieee.org 1; Ochoa@ieee.org 2; Vhinostr@uacj.mx 3
Article received on April 06, 2006
Accepted on October 19, 2006
Abstract
We present the design and analysis of a MEMS variable capacitor coupled to thermal actuators. The variable capacitor is composed by two main components: 1) the capacitor built by two squared plates, which one plate is mechanically fixed to the substrate and the other is a moving plate having mechanical suspensions (springs) connected from each corner of it to the substrate, and 2) a set of thermal actuators that push the moving plate away from the substrate. Depending on the power applied on the thermal actuators, these would push up the variable plate from its sides, while the suspension pulls the plate down to the substrate for equilibrium. This work includes the design fabrication steps using PolyMUMPSTM process, and provides tables for the resulting values of the variable capacitors. The results accomplished using COVENTORWARETM software show that the variable capacitor has potential for automatic compensation of capacitances and for integration into frequency oscillators and filters.
Keywords: MEMS Design, MEMS FEA, Variable Capacitors, Thermal Actuators.
Resumen
En éste trabajo presentamos el diseño con tecnologías MEMS y análisis de un capacitor variable acoplado a actuadores térmicos. El capacitor variable está compuesto por dos componentes importantes: 1) el capacitor construído de dos capas cuadradas paralelas, en donde una placa está mecánicamente fija al sustrato y la otra es una placa movible la cual tiene resortes flexibles conectados de cada esquina de la placa al substrato, y 2) un arreglo de actuadores térmicos que separan la placa movible del substrato. Dependiendo de la potencia aplicada a los actuadores térmicos, éstos empujaran la placa variable por las secciones laterales para separar la placa del substrato, mientras que los resortes de suspensión contrarrestan la fuerza mecánica para mantener el equilibrio. Éste trabajo incluye los pasos de diseño y fabricación utilizando el proceso PolyMUMPSTM, y proporciona tablas de los resultados obtenidos destacando la funcionabilidad de los capacitares variables. Además, se presentan los resultados obtenidos utilizando el software COVENTORWARETM, donde mostramos el potencial de uso del capacitor variable para la realización de compensaciones automáticas de capacitancias dinámicas para la integración al desarrollo de osciladores de frecuencia y filtros.
Palabras clave: Diseño de MEMS, Análisis de elementos finitos de MEMS, capacitares variables, actuadores térmicos.
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