Study on MEMS Capacitive Differential Pressure Sensor

2014 ◽  
Vol 609-610 ◽  
pp. 968-971
Author(s):  
Zhi Hao Hou ◽  
Zhen Huang ◽  
Shi Xing Jia
Keyword(s):  
Pressure Sensor ◽  
Applied Pressure ◽  
Differential Pressure ◽  
Anodic Bonding ◽  
Capacitive Pressure Sensor ◽  
Silicon Membrane ◽  
Fixed Electrode ◽  
Differential Pressure Sensor ◽  
Application Requirements ◽  
Gold Metal

The design and fabrication of MEMS capacitive differential pressure sensor is reported. Silicon membrane is used as movable electrode. Gold metal film on glass is used as fixed electrode. Anodic bonding is used to bond together the silicon and glass to form the capacitive pressure sensor. The measurement capacitance of the sensors is 5.37 pF at an applied pressure of 0 kPa and 7.26 pF and the full operating range of 40 kPa.The ratio of changed to initial capacitance was 0.35. The error of the MEMS capacitive pressure sensor is less than 4‰ full-scale(FS) by using quadratic curve fitting which can meet most application requirements.

Peeling Mode Capacitive Pressure Sensor for Sub-KPA Pressure Measurements

2006 ◽  
Author(s):  
Jeahyeong Han ◽  
Shunzhou Yang ◽  
Mark A. Shannon
Keyword(s):  
Residual Stresses ◽  
Pressure Sensor ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Capacitive Pressure Sensor ◽  
Resistance To Deformation ◽  
Fixed Electrode ◽  
Electrostatic Pressure ◽  
Nonlinear Signal ◽  
Low Pressures

Capacitive pressure sensors measure changes in pressure typically by the deflection of a flexible conducting membrane towards a fixed electrode. The deflection in the membrane produces a quadratic change in capacitance, which often yields higher sensitivity to changes in pressure compared to piezo-resistive pressure sensors, which measures the resistance changes proportional to the applied pressure. However, residual stresses in the membrane can provide a substantial resistance to deformation compared to the driving force created by the applied pressure, which decreases the sensitivity at low pressures and produces a nonlinear signal. If the membrane is made compliant enough to increase sensivitiy, pull-in of the membrane can occur, reducing the effective pressure range of the capacitive manometer type pressure sensor. Hence, these type of sensors are typically not used to measure very low pressure differences over several hundred Pascals. To overcome this limitation, a capacitive pressure sensor was developed that operates in a peeling mode while under applied electrostatic actuation, which counters the residual stresses. The changes in capacitance can be detected if the pressure is just enough to overcome the interfacial electrostatic pressure. This type of pressure sensor can potentially be used for very low differential pressure differences, well below 100 Pa, over ~ 1 kPa range.

Capacitance pressure sensor with S-type electrode for improved sensitivity

2021 ◽  
pp. 014233122110080
Author(s):  
Santhosh KV ◽  
Swetha Rao
Keyword(s):  
Pressure Sensor ◽  
Pressure Sensors ◽  
Differential Pressure ◽  
Capacitive Pressure Sensor ◽  
Input Output ◽  
Capacitance Pressure ◽  
Output Behavior ◽  
Output Characteristics ◽  
Differential Pressure Sensor ◽  
Output Capacitance

This paper aims at designing a differential pressure sensor. The objective of the work is to design and fabricate the electrodes of a capacitive pressure sensor, so as to measure absolute and differential pressure accurately with improved sensitivity. In place of conventional parallel plate diaphragm, S-type electrodes are proposed in the present work. The work comprises of study of the proposed design in terms of a mathematical model, input-output behavior along with detailed analysis of pressure distribution pattern. Output capacitance obtained for changes in pressure is converted to voltage with the suitable signal conditioning circuit and data acquisition system to acquire the signal on to a PC. A neural network model is designed to compensate the nonlinearities present in the sensor output. Input-output characteristics of the designed sensor shows an improved response as compared with existing pressure sensors.

Development of circuit solution and design of capacitive pressure sensor array for applied robotics

2020 ◽  
Vol 8 (4) ◽  
pp. 296-307
Author(s):  
Konstantin Krestovnikov ◽  
Aleksei Erashov ◽  
Аleksandr Bykov
Keyword(s):  
Pressure Sensor ◽  
Output Signal ◽  
Sensor Array ◽  
Applied Pressure ◽  
Pressure Sensors ◽  
Fine Tuning ◽  
Capacitive Pressure Sensor ◽  
Cell Parameters ◽  
Linear Pattern ◽  
Sensor Structure

This paper presents development of pressure sensor array with capacitance-type unit sensors, with scalable number of cells. Different assemblies of unit pressure sensors and their arrays were considered, their characteristics and fabrication methods were investigated. The structure of primary pressure transducer (PPT) array was presented; its operating principle of array was illustrated, calculated reference ratios were derived. The interface circuit, allowing to transform the changes in the primary transducer capacitance into voltage level variations, was proposed. A prototype sensor was implemented; the dependency of output signal power from the applied force was empirically obtained. In the range under 30 N it exhibited a linear pattern. The sensitivity of the array cells to the applied pressure is in the range 134.56..160.35. The measured drift of the output signals from the array cells after 10,000 loading cycles was 1.39%. For developed prototype of the pressure sensor array, based on the experimental data, the average signal-to-noise ratio over the cells was calculated, and equaled 63.47 dB. The proposed prototype was fabricated of easily available materials. It is relatively inexpensive and requires no fine-tuning of each individual cell. Capacitance-type operation type, compared to piezoresistive one, ensures greater stability of the output signal. The scalability and adjustability of cell parameters are achieved with layered sensor structure. The pressure sensor array, presented in this paper, can be utilized in various robotic systems.

Single-chip solution for electronics unit of a smart pressure sensor

Sensor Review ◽  
2020 ◽  
Vol 40 (5) ◽  
pp. 529-534
Author(s):  
Igor S. Nadezhdin ◽  
Aleksey G. Goryunov
Keyword(s):  
Pressure Sensor ◽  
Sensitive Element ◽  
Noise Immunity ◽  
Pressure Sensors ◽  
Cost Effective ◽  
Differential Pressure ◽  
Manufacturing Cost ◽  
Content Type ◽  
Differential Pressure Sensor ◽  
Developed Pressure

Purpose Differential pressure is an important technological parameter, one urgent task of which is control and measurement. To date, the lion’s share of research in this area has focused on the development and improvement of differential pressure sensors. The purpose of this paper is to develop a smart differential pressure sensor with improved operational and metrological characteristics. Design/methodology/approach The operating principle of the developed pressure sensor is based on the capacitive measurement principle. The measuring unit of the developed pressure sensor is based on a differential capacitive sensitive element. Programmable system-on-chip (PSoC) technology has been used to develop the electronics unit. Findings The use of a differential capacitive sensitive element allows the unit to compensate for the influence of interference (for example, temperature) on the measurement result. With the use of PSoC technology, it is also possible to increase the noise immunity of the developed smart differential pressure sensor and provide an unparalleled combination of flexibility and integration of analog and digital functionality. Originality/value The use of PSoC technology in the developed smart differential pressure sensor has many indisputable advantages, as the size of the entire circuit can be minimized. As a result, the circuit has improved noise immunity. Accordingly, the procedure for debugging and changing the software of the electronics unit is simplified. These features make development and manufacturing cost effective.

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