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Abstract
Determination of the rate of energy loss in a reverberation chamber is fundamental to many different measurements such as absorption cross-section, antenna efficiency, radiated power, and shielding effectiveness. Determination of
the energy decay time-constant in the time-domain by linear fitting the power delay profile, rather than using the frequency-domain quality factor, has the advantage of being independent of the radiation efficiency of antennas used in the measurement. However, determination of chamber time constant by linear
regression suffers from several practical problems, including a requirement for long measurement times. Here we present a new nonlinear curve fitting technique that can extract the time-constant with typically 60% fewer samples of the chamber transfer function for the same measurement uncertainty, which enables faster measurement of chamber time constant by sampling fewer chamber transfer function, and allows for more robust automated data post-processing. Nonlinear curve fitting could have economic benefits for test-houses, and also enables accurate broadband measurements on humans in about ten minutes for microwave exposure and medical applications. The accuracy of the nonlinear method is demonstrated by measuring the absorption cross-section of several test objects of known properties. The measurement uncertainty of the method is verified using Monte Carlo methods.
the energy decay time-constant in the time-domain by linear fitting the power delay profile, rather than using the frequency-domain quality factor, has the advantage of being independent of the radiation efficiency of antennas used in the measurement. However, determination of chamber time constant by linear
regression suffers from several practical problems, including a requirement for long measurement times. Here we present a new nonlinear curve fitting technique that can extract the time-constant with typically 60% fewer samples of the chamber transfer function for the same measurement uncertainty, which enables faster measurement of chamber time constant by sampling fewer chamber transfer function, and allows for more robust automated data post-processing. Nonlinear curve fitting could have economic benefits for test-houses, and also enables accurate broadband measurements on humans in about ten minutes for microwave exposure and medical applications. The accuracy of the nonlinear method is demonstrated by measuring the absorption cross-section of several test objects of known properties. The measurement uncertainty of the method is verified using Monte Carlo methods.
Original language | English |
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Pages (from-to) | 1296-1303 |
Journal | IEEE Transactions on Electromagnetic Compatibility |
Volume | 60 |
Issue number | 5 |
Early online date | 14 Dec 2017 |
DOIs | |
Publication status | Published - Oct 2018 |
Bibliographical note
© 2017 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.Submitted 1 August 2017, Accepted 2 Nov 2017, Online 14 Dec 2017
Keywords
- Antenna measurements
- Frequency measurement
- Loss measurement
- Measurement uncertainty
- Signal to noise ratio
- Time measurement
- Absorption cross section (ACS)
- Monte Carlo method
- chamber time constant
- inverse Fourier transform
- power balance method
- power delay profile (PDP)
- reverberation chamber (RC)
Projects
- 1 Active
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Reverberation chamber measurement of Human body electromagnetic absorption cross section
Robinson, M. P., Flintoft, I. D., Melia, G. C. R., Zhang, X., Dawson, J. F. & Marvin, A.
1/12/08 → …
Project: Other project › Miscellaneous project