The electromagnetic interaction between biological tissue and antennas on a transceiver handset

In the design of antennas for use with hand-held transceivers, the electromagnetic interaction between the antenna and the nearby biological tissue is a key factor which must be considered when selecting the antenna configuration. The engineer must consider the effect of the body on the antenna performance as well as the rate at which energy is absorbed in the tissue. Investigation of such issues can be performed through numerical simulation provided that the antenna, handset, and adjacent tissue are represented with detailed models and that accurate solution methodologies such as the finite-difference time-domain (FDTD) approach are used. Past studies have appeared which use the FDTD method either with simple models of the head (e.g. a homogeneous sphere) or simple antenna models to predict the interaction between the antenna and the nearby tissue. The present paper combines detailed models of the head and hand with real-life models of antennas on transceiver units to predict the input impedance, radiation patterns, gain, and specific absorption rate (SAR) which result when the handset operates in the proximity of a human. Results are shown for both the monopole and planar inverted F antenna (PIFA) to illustrate the interaction for external and internal antennas respectively.<>