HO_funded_projects

Research

Project Title:
Nonlinear and Demodulation Mechanisms in Biological Tissue

Start Date:
September 2004

Expected date of completion:
July 2008

Cost:
£ 255,695

Principal investigator:
Professor Peter S. Excell, University of Bradford

Contact details:
School of Informatics, University of Bradford, Bradford BD7 1DP
Email: p.s.excell@bradford.ac.uk

Project team:
University of Bradford:
Professor Peter S. Excell, Professor of Applied Electromagnetics
Dr Raed Abd-Alhameed, Senior Lecturer in Applied Electromagnetics
Mr Iftekhar Ahmed, Research Assistant

University of Maryland:
Professor Christopher Davis, Professor of Electrical and Computer Engineering
Professor Quirino Balzano, Professor of Wireless Communications
Research Assistant TBA

National Radiological Protection Board:
Dr Simon Bouffler

Expertise:
The project is managed by the University of Bradford, with a major subcontract to the University of Maryland. There is also an associated contract with the National Radiological Protection Board, let directly by the MTHR board.

The project is co-ordinated by Professor Peter Excell, Professor of Applied Electromagnetics, University of Bradford. He will work closely with his key team member, Dr Raed Abd-Alhameed, Senior Lecturer in Applied Electromagnetics, with whom he has built up a unique range of skills in high-frequency computational electromagnetics. This expertise will be used, in particular, to model the electromagnetic behaviour of the biological samples in the middle of a large resonant microwave cavity, and the distribution of fields within the sample. His other areas of expertise include Electromagnetic Compatibility, Radio Frequency Ignition Hazards, Antenna Design and Wireless Device Applications.

The research assistant that has been recruited at Bradford, Mr Iftekhar Ahmed, has a 1st Class BEng/MEng Honours degree in Electronic, Telecommunication and Computer Engineering and has worked on precision radio frequency measurements in industry (Combline Filters, Low noise Amplifiers, Photonics and Optical Networks).

The collaborating group at the University of Maryland is led by Professor Christopher Davis, Professor of Electrical and Computer Engineering. His research interests include lasers, quantum optics, near-field scanning microscopy, nonlinear imaging, dielectrometry, optical/fiber sensors and biosensors, magnetooptics, optical communication systems and devices, and biophysics.

In 2001, this group was joined by Professor Quirino Balzano, Professor of Wireless Communications (formerly with Motorola, Fort Lauderdale), who has long experience in the bioelectromagnetics field. The present project is fundamentally based on an idea that he proposed in the journal Bioelectromagnetics (Proposed Test for the Detection of Nonlinear Responses in Biological Preparations Exposed to RF Energy, Bioelectromagnetics, Vol. 23, pp. 278-287, 2002).

Building on early work in antennas and electromagnetics, from 1976 Professor Balzano devoted his efforts to research of the bio-effects of electromagnetic exposure, with particular attention to effects in the near field of RF sources. He performed high precision measurements to determine the amount of electromagnetic energy that couples from a portable radio to the face of the user. In 1978 he was appointed Manager of the Antenna and Digital System Research Laboratory, and in 1987 Vice President of the Technical Staff of Motorola and Manager of Communication Systems research. In 1988 he was appointed Vice President and Director of the Portable Products Division, and in 1990 Vice President of the Technical Staff of the Radio Products Group. He was in charge of portable radio antenna development and directed Motorola Research in matters of RF exposure safety. In 1993 he was elected to the position of Corporate Vice President of Motorola and Director of the Corporate Electromagnetic Research Laboratory. In 1998 he was given the additional directorship of the Motorola Florida Laboratories. In February, 2001 he retired from Motorola to pursue his teaching and research interests at the University of Maryland. He holds 27 patents in antenna and integrated circuit technologies, a certificate of merit from the North American Radiological Society for his work on treating tumours with RF energy, and the Dan Noble Fellowship, the highest award within Motorola for technical achievements. He is vice chairman of IT”IS, a laboratory dedicated to RF dosimetry, affiliated with the Swiss Federal Polytechnic University, Zürich, Switzerland. He is a Charter Member of the Bioelectromagnetics Society, and a member of IEEE committees SCC-28 (Human Safety with Respect to Radio frequency Electromagnetic Energy) and SCC-34 (Electromagnetic Energy Performance Safety).

The third partner is the National Radiological Protection Board, which is an independent public body set up under the Radiological Protection Act 1970. Its role is to provide advice to protect the health of the public, workers who are occupationally exposed and patients undergoing medical treatment, from hazards of radiation. Its remit covers both ionising and non-ionising radiation. Dr Simon Bouffler, of the Radiation Effects Department, co-ordinates the separate subcontract there. He has extensive experience of experimental procedure for handling biological samples under conditions designed to maximise repeatability of results. He has published extensively in the low-level ionising-effects literature.

Approch:
Since the basic idea was proposed by Prof. Q. Balzano, now of the University of Maryland, the test equipment will be built in Maryland in close collaboration with the Bradford University group, who will contribute their electromagnetic modelling skills. After testing and refinement, and further shakedown testing in Bradford, it will be taken to the National Radiological Protection Board headquarters at Didcot, where the biological samples will be introduced under controlled conditions and the main experiments will be undertaken.

The experiments will be conducted in at least four phases.

1: Testing of the empty cavity
2: Testing of the cavity with the empty sample holder placed within the cavity.
3: Control testing of non-biological liquids, e.g. nutrient solution.
4: Testing of the cavity with the biological samples inserted.

Potential Difficulties:
1. It is very difficult to conceive of a realistic physical mechanism that could achieve demodulation from mobile-phone frequencies in human tissue and, as a result, any effect can be expected to be extremely weak (if not non-existent).

2. The major difficulty envisaged will be the reliable detection of the possible second harmonic generated. Small amounts of non-linearity in the structure of the test equipment could easily produce spurious results, and hence a large amount of effort is expected to be necessary in identifying and eliminating these.

Importance:
The object is to test for the ability of human tissue to demodulate the radio waves transmitted from mobile phones, since this has been repeatedly proposed as a mechanism for the highly amplitude-modulated waves from second-generation phones to interact with low frequency bioelectrical processes. In rigorous terms, any such demodulation device must have a square-law relationship between applied signal strength and induced current, and a sensitive test for such behaviour is to look for generation of the second harmonic frequency when a tissue sample is placed in a very pure single-frequency electromagnetic field at a typical mobile frequency.