MEMS based humidity sensor using Si cantilever beam for harsh environmental conditions

Abstract

Sensing and controlling of humidity is a major issue in various industries. Many of the equipments in industries require monitoring and controlling humidity for its efficient and reliable operation. This paper presents the design, fabrication and complete characterization of a micro cantilever based humidity sensor for harsh environmental conditions. A Si cantilever humidity sensor based on capacitive principle is designed and displacement analysis is performed on the sensor. The polyimide, acts as a sensing material for this sensor. The polyimide is coated over the beam to sense the humidity. If the humidity absorbed by the polyimide material increases, the mass of the beam is also increased. The deflection of the beam causes the change in capacitance. The relative humidity can be calculated using the change in capacitance. The beam had an appreciable deflection causing a notable change in capacitance. The variation of capacitance is in the order of picofarads. The sensor is designed in a structure that can tolerate the harsh environmental conditions like pressure, temperature, etc.

Effects of slots on thermoelastic quality factor of a vertical beam MEMS resonator

“…However developing a MEMS resonator with high quality factor in MHz frequency ranges, which would be compatible with CMOS integrated circuits (Dragoi et al 2012) is very important in view of different applications. In integrated circuits, applications such as filters (Bannon et al 2000;Lopez et al 2009), timing and reference frequency devices (Lin et al 2004;Nguyen 2007), microprocessors (Abdelsalam et al 2010) and sensors such as pressure and humidity sensors (Shi et al 2013;Muniraj 2011) facing an important challenge either from scientific or engineering viewpoint that must be well addressed. As an important property, Quality factor (Q) is a scaled ratio between stored energy and damped energy per cycle, which is associated with frequency.…”

Design and characterization of an integrated multifunction micro sensor

“…Many academic institutions are carrying on pertinent researches and a number of silicon micro sensors for measuring acceleration, pressure, temperature, humidity, force, flow and others have been developed (Muniraj 2011;Yu-Ming et al 2010;Jiachou and Xinxin 2010;Bian et al 2009). Some of these sensors have been commercialization and used in many fields, including in the motor, airplane, machine tool and other system for real-time monitoring (Xide et al 2009;Ong et al 2001).…”

A Trade-Off for Frequency -Voltage Dependence of RF MEMS Switch

“…This paper purposes to improve the performance of RF MEMS series switch for better performance in terms of voltage actuation, loss and isolation. A low voltage of MEMS switch is desirable because it will make it more convenient to be embedded into real applications [13].In this paper we try to design new geometrical structure, parameters of the electrostatic area of the gap that control the switching voltage to achieve a maximum frequency response for the switch at lower driving voltage and beams length.…”