High-resolution measurements of the specific absorption rate produced by small antennas in lossy media

Author

Mirotznik, Mark S. ; Cheever, Erik ; Foster, Kenneth R.

Author_Institution

Dept. of Electr. Eng., Catholic Univ. of America, Washington, DC, USA

Volume

45

Issue

3

fYear

1996

fDate

6/1/1996 12:00:00 AM

Firstpage

754

Lastpage

756

Abstract

We describe a thermistor-based technique for measurement of the specific absorption rate (SAR) of radio frequency energy from a small antenna in lossy matter with high spatial resolution. The apparatus employs a small thermistor probe, that is moved about the antenna using a computer-controlled positioning system. The antenna is excited by pulses of radio frequency energy, and the SAR is obtained from the measured rate of temperature increase. We present a simplified thermal model to account for heating of the thermistor by the applied electromagnetic energy, which is a major potential artifact in the method. The apparatus is useful for studies of radio frequency ablation of tissue or near-field exposure in models of the body by transmitters

Keywords

electromagnetic wave absorption; radiofrequency heating; temperature measurement; thermistors; transmitting antennas; body exposure; computer-controlled positioning system; electromagnetic energy; heating; high-resolution measurements; lossy media; radio frequency energy; small antennas; specific absorption rate; temperature measurement; thermal model; thermistor probe; tissue ablation; transmitters; Antenna measurements; Energy measurement; Frequency measurement; Loss measurement; Pulse measurements; Radio frequency; Spatial resolution; Specific absorption rate; Temperature measurement; Thermistors;

fLanguage

English

Journal_Title

Instrumentation and Measurement, IEEE Transactions on

Publisher

ieee

ISSN

0018-9456

Type

jour

DOI

10.1109/19.494594

Filename

494594