skip to main content

SciTech ConnectSciTech Connect

Title: A microfabricated fringing field capacitive pH sensor with an integrated readout circuit

This work presents a microfabricated fringe-field capacitive pH sensor using interdigitated electrodes and an integrated modulation-based readout circuit. The changes in capacitance of the sensor result from the permittivity changes due to pH variations and are converted to frequency shifts using a crossed-coupled voltage controlled oscillator readout circuit. The shift in resonant frequency of the readout circuit is 30.96 MHz for a change in pH of 1.0–5.0. The sensor can be used for the measurement of low pH levels, such as gastric acid, and can be integrated with electronic pills. The measurement results show high repeatability, low noise, and a stable output.
Authors:
; ;  [1] ; ; ;  [2]
  1. Electrical and Computer Systems Engineering, Monash University, Melbourne (Australia)
  2. Mechanical and Aerospace Engineering, Monash University, Melbourne (Australia)
Publication Date:
OSTI Identifier:
22300108
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 104; Journal Issue: 22; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CAPACITANCE; ELECTRIC POTENTIAL; ELECTRODES; MHZ RANGE; MODULATION; NOISE; OSCILLATORS; PERMITTIVITY; PH VALUE; READOUT SYSTEMS; SENSORS