Passive Wireless Multi-Parameter Sensor System for Hermetic Environment Monitoring

Abstract:

This paper presents a passive wireless multi-parameter sensor system, which is suitable for monitoring the environment in hermetic space like industrial painting room, coal mine, and so on. The system consists of two subsystems: the primary system and the secondary system. The primary system transmits power and receives modulated data through a coupled transformer composed of primary and secondary inductors printed in their subsystems, respectively. The secondary system comprises micro capacitive temperature, pressure and relative humidity sensors and uses a relaxation oscillator to convert capacitance to frequency. Using time division multiplexing unit, it can simultaneously measure multiple sensors. The converted frequency signal is used to vary the amplitude of the waveforms on the coupling inductors. The modulating signal is recovered from the carrier using the envelope detection unit. The measurement results indicate that the pressure, temperature, and relative humidity sensitivities of the passive wireless multi-parameter sensor system are 5.6 fF/hPa, 250fF/°C and 71.4 fF/%RH, respectively. Three sensors linearly response to the change of the environment and the system has good consistency.

• Periodical: Key Engineering Materials (Volumes 645-646)
• Pages: 583-588
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.645-646.583
• Online since: May 2015
• Authors: Dan Tang, Li Feng Wang, Qing An Huang*
• Keywords: Asynchronous Communication, Coupling Inductors, Load Modulation, Multi-Parameter, Passive, Relaxation Oscillator, Time Division Multiplexing, Wireless

References

[1] J. Landt, The history of RFID, Potentials, IEEE, 24 (2005) 8-11.

[2] M Merenda, C Felini, F G Della Corte, Battery-less smart RFID tag with sensor capabilities, RFID-Technologies and Applications, IEEE International Conference, (2012) 160-164.

DOI: 10.1109/rfid-ta.2012.6404503

[3] Q Huang, M Oberle, A 0. 5-mW passive telemetry IC for biomedical applications, Solid-State Circuits, IEEE, 33. 7(1998)937-946.

DOI: 10.1109/4.701225

[4] T Akin, K Najafi, R M Bradley, A wireless implantable multichannel digital neural recording system for a micromachined sieve electrode, Solid-State Circuits, IEEE, 33. 1(1998) 109-118.

DOI: 10.1109/4.654942

[5] B. D. Farnsworth, R. J. Triolo, D. J. Young, Wireless implantable EMG sensing microsystem, IEEE. (2008) 1245-1248.

DOI: 10.1109/icsens.2008.4716669

[6] K E Kunkel, Operational soil moisture estimation for the midwestern United States, Journal of Applied Meteorology, 29. 11(1990)1158-1166.

DOI: 10.1175/1520-0450(1990)029<1158:osmeft>2.0.co;2

[7] R. Puers, Capacitive sensors when and how to use them, Sens. Actuators A, Phys., 37- 38(1993)93-105.

DOI: 10.1016/0924-4247(93)80019-d

[8] D Cirmirakis, A Demosthenous, N Saeidi, et al. Humidity-to-frequency sensor in CMOS technology with wireless readout, Sensors Journal, IEEE, 13. 3(2013) 900-908.

DOI: 10.1109/jsen.2012.2217376

[9] T Salpavaara, J Verho, P Kumpulainen, et al. Readout methods for an inductively coupled resonance sensor used in pressure garment application, Sensors and Actuators A: Physical, 172. 1(2011)109-116.

DOI: 10.1016/j.sna.2011.02.051

[10] Y Wang, Y Jia, Q Chen, et al. A passive wireless temperature sensor for harsh environment applications, Sensors, 8. 12(2008)7982-7995.

DOI: 10.3390/s8127982

[11] A D DeHennis, K D Wise. A wireless microsystem for the remote sensing of pressure, temperature, and relative humidity, Microelectromechanical Systems, 14. 1(2005)12-22.

DOI: 10.1109/jmems.2004.839650