Calibration model for detection of potential demodulating behaviour in biological media exposed to RF energy

See, Chan H.; Abd-Alhameed, Raed A.; Ghani, Arfan; Ali, Nazar T.; Excell, Peter S.; McEwan, Neil J.; Balzano, Quirino

Abstract

Potential demodulating ability in biological tissue exposed to radio-frequency (RF) signals intrinsically requires an unsymmetrical diode-like non-linear response in tissue samples. This may be investigated by observing possible generation of the second harmonic in a cavity resonator designed to have fundamental and second harmonic resonant frequencies with collocated antinodes. Such a response would be of interest as being a mechanism that could enable demodulation of information-carrying waveforms having modulating frequencies in ranges that could interfere with cellular processes. Previous studies have developed an experimental system to test for such responses: the present study reports a circuit model to facilitate calibration of any non-linear RF energy conversion occurring within a test-piece inside the cavity. The method is validated computationally and experimentally using a well-characterised non-linear device. The proposed model demonstrates that the sensitivity of the measurement equipment plays a vital role in deciding the required input power to detect any second harmonic signal, which is expected to be very weak. The model developed here provides a lookup table giving the level of the second harmonic signal in the detector as a function of the input power applied in a measurement. Experimental results are in good agreement with the simulated results.

• Journal Article Type: Article
• Acceptance Date: May 11, 2017
• Publication Date: Oct 1, 2017
• Deposit Date: Mar 14, 2019
• Publicly Available Date: Mar 18, 2019
• Journal: IET Science, Measurement & Technology
• Electronic ISSN: 1751-8830
• Publisher: Institution of Engineering and Technology (IET)
• Peer Reviewed: Peer Reviewed
• Volume: 11
• Issue: 7
• Pages: 900-906
• DOI: https://doi.org/10.1049/iet-smt.2017.0105
• Keywords: cavity resonators; biological tissues; table lookup; calibration; medical signal detection; harmonic generation; biological techniques; demodulation
• Public URL: http://researchrepository.napier.ac.uk/Output/1660353
• Contract Date: Mar 14, 2019