Research

Project Title:
Assessment of Specific Energy Absorption Rate (SAR) in the Head from TETRA Handsets

Start Date:
March 2002

Status:
Completed

Cost:
£75,000

Principal Investigator:
Dr Peter Dimbylow

Contact Details:
National Radiological Protection Board
Chilton
Didcot
OX11 0RQ

Expertise:

The research team at NRPB has many years’ experience in electromagnetic field calculations and measurement. It is one of the world leaders in the development of realistic anatomically accurate models of the human body and their application to problems of how electromagnetic fields and ionising radiation interact with the body.

Approach:

It is proposed to calculate the distribution of power absorbed in an anatomically realistic model of the head from Terrestrial Enhanced Trunked Radio (TETRA) hand-sets. TETRA is a modern digital private mobile radio system designed to meet the requirements of professional users, such as the police and fire brigade. The TETRA hand-sets use a helical antenna, and it is important to experimentally verify the mathematical description of this antenna type. The study will be performed in two parts. A mathematical model of the helical antenna and TETRA handset will be produced. This model will be validated by comparing predicted field distributions close to the handset with experimentally measured values in the absence of the head. On the successful completion of the first part, coupled head/handset calculations with the handset and the head will be performed. The calculated power absorbed in the head will be compared with the basic restrictions from safety guidelines to assess compliance.

Novel Aspects:

The novel aspects of this work are to produce an accurate model of a TETRA handset and then perform calculations of the energy absorbed in the head from this handset. The NRPB approach to electromagnetic field calculations is to use a computer code that has been developed in-house to enable the flexibility to update and tailor the software to particular applications. A further advantage of the NRPB approach is that it is a complementary, using calculations and measurement to validate the accuracy of the numerical model of the handset.

Importance:

The proposal addresses the IEGMP research recommendation for improvements in dosimetry. The calculated energy absorbed in the head from TETRA handsets will be compared with international guidelines on basic restrictions to assess compliance.