Chapter 7
Electromagnetic Compatibility Considerations
7.1 Introduction
Body area communications makes an electromagnetic field source just on or in the human body. Electromagnetic radiation from a body area communication device may give rise to energy absorption in the human body as well as possible interference with medical devices. This implies a potential for possible biological effects as well as malfunction of medical devices that are worn by or implanted in a human body. Both of these electromagnetic compatibility (EMC) issues have to be considered in the design of a body area communication system.
Biological effects caused by exposure to RF fields are related to the electric and magnetic fields inside the human body. The distribution of the internal fields is related to a number of parameters, including the communication frequency, the dielectric properties of tissues, the geometrical shape of the human body, and the antenna structure of the transmitter of body area communications. The interaction of the induced electromagnetic fields with the human body results in the flow of electric current, the polarization of bound charge (formation of electric dipoles), and the reorientation of electric dipoles already present in human tissue. The electrical conductivity governs the flow of electric current, and the permittivity governs the magnitude of polarization effects.
Current knowledge tells us that there are mainly two types of biological effects of electromagnetic fields. ...
