An evanescent-mode cavity resonator based thermal sensor

Aamer Mahmood, Hjalti H. Sigmarsson, Himanshu Joshi, William J. Chappell, Dimitrios Peroulis

Research output: Chapter in Book/Report/Conference proceedingConference contribution

16 Citations (Scopus)


This paper reports the use of an evanescent-mode cavity resonator as a temperature sensor. The frequency loading is achieved by a capacitive post in the center of the cavity confining the electric field in a small volume. The resonant frequency of a loaded evanescent-mode cavity is related to the capacitance of the loading mechanism. As a sensing mechanism, a rectangular array of thermally actuated bilayered microcantilever beams on a silicon substrate has been fabricated using conventional microfabrication processes and placed inside the resonator. A temperature change causes the microcantilevers to deflect, changing the parasitic capacitance of the cavity and hence the resonant frequency of the resonator. Loaded microwave cavities have been fabricated using a layer by layer stereolithographic process and then metallized. The Si hosting the cantilevers is attached to the cavity. The resonant frequency of the sensor is monitored as a function of temperature and varies from 11.34 GHz at room temperature to 12 GHz at 90°C. At room temperature, the sensor has a Temperature Coefficient of Frequency (TCF) of 0.029%/°C.

Original languageEnglish
Title of host publicationThe 6th IEEE Conference on SENSORS, IEEE SENSORS 2007
Number of pages4
Publication statusPublished - 1 Dec 2007
Event6th IEEE Conference on SENSORS, IEEE SENSORS 2007 - Atlanta, GA, United States
Duration: 28 Oct 200731 Oct 2007

Publication series

NameProceedings of IEEE Sensors


Other6th IEEE Conference on SENSORS, IEEE SENSORS 2007
CountryUnited States
CityAtlanta, GA


ASJC Scopus subject areas

  • Electrical and Electronic Engineering

Cite this

Mahmood, A., Sigmarsson, H. H., Joshi, H., Chappell, W. J., & Peroulis, D. (2007). An evanescent-mode cavity resonator based thermal sensor. In The 6th IEEE Conference on SENSORS, IEEE SENSORS 2007 (pp. 950-953). [4388560] (Proceedings of IEEE Sensors).