Informatics Publishing Limited

Khawaja Nizammuddin Subhani ¹, Shubham Khandare ¹, Rajashekhar C. Biradar ², K. N. Bhat ¹

Affiliations
1 Indian Institute of Science, Bangalore, IN
2 REVA University, Bangalore, IN

Abstract

Most of the MEMS structures use proof mass to reduce the frequency but increases the device dimension. This paper deals with the variation of natural frequency and stiffness of the structure when changed from rectangular to multi-turn meander structure. The suspended meander structures are designed with silicon nitride and simulation were carried using COMSOL Multiphysics FEM model to investigate the natural frequency and deflection of the structure by varying the number of turns ‘N’. The simulation and Analytical results show an impact with variation of N on the natural frequency of the structure when the distance between the fixed-fixed beam is kept constant. Further investigation is carried out on the stiffness variation of multi-turn meander structure with fixed at one end.

Keywords

Meander, Stiffness, Natural Frequency.

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Nithin ¹, Rathnamala Rao ², K. N. Bhat ¹

Affiliations
1 Indian Institute of Science, Bangalore, IN
2 NITK Surathakal, Mangalore, IN

Abstract

In this paper the MEMS pressure sensor with sculptured diaphragm is designed, fabricated and tested for measuring low pressure range (0 - 600mbar). The classical flat diaphragm sensors give rise to linearity error and offset drift problem when it is used for wide range of temperature. If the offset drift and linearity error is high then compensation of the sensor with external electronics also becomes very tedious process and impossible in some cases. So, in this paper initially simulation study is discussed to optimize the sculptured diaphragm structure dimensions, to measure low pressure like 600mbar for the wide temperature range from -40°C to 80°C. COMSOL simulator tool is used to estimate the stress values on the diaphragm, and use these values to analytically determine the sensor output for different temperatures. With this simulation approach, the effect of temperature on the zero offset drift and linearity is studied. Based on the simulated structure, the diaphragm and resistor dimensions are decided and the optimized structure is fabricated using SOI wafer technology in clean room and tested for the same specifications. Finally, the simulated and practically obtained results are discussed and compared.

Keywords

MEMS Pressure Sensor, Sculptured Diaphragm, SOI Wafer.

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B. Pavithra ¹, C. Linet Thomas ¹, N. Veera Pandi ¹, K. Sankaran ¹, Nithin ¹, Smitha G. Prabhu ², K. N. Bhat ¹

Affiliations
1 Indian Institute of Science, Bangalore, IN
2 NMIT, Bangalore, IN

Abstract

In this Paper, we present the effect of active (programmable) temperature compensation for 0-200Bar in house developed Aerospace quality MEMS gauge Pressure Transducers using ZMD based IC. Two numbers of 0-200 Bar Gauge Pressure MEMS Transducer’s raw output (in mV) was compared with temperature and span compensated amplified output values (in Volts). The drift values were calculated. The effect of Nonlinearity+Hysteresis, Full Scale Output (FSO) and Zero Offset for various input temperatures were tabulated and a graph was drawn. A Static hydraulic dead weight calibrator (Fluke Make P3125) was used and a linear relation between Pressure Vs Output was obtained. The raw output data in mV as well as temperature (-40ºC to +80ºC) compensated output (in Volts) was plotted with respect to input Pressure. The Non linearity +Hysteresis value after temperature compensation was found to be 0.3%FSO. Temperature drift values obtained were better than 2 x 10-4/FSO/ºC.

Keywords

MEMS Pressure Transducer, Temperature compensation, Nonlinearity+Hysteresis.

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