The effects of a nearby biological body on the parameters of a small hand-held radio operating in the H.F. band (3MHz-30MHz)

The effects of a nearby biological body on the efficiency and radiation patterns of a small hand-held radio operating in the H.F. band are determined by computer modeling. The close proximity of the radio operator's body results in the scattered field from the body reradiating and perturbing the known free-space current distribution in the antennas to some extent. However, due to the extremely small electrical size of the radiating system, this body-to-radio coupling is assumed to be minimal and henceforth neglected. Thus, a direct moment method is used to solve a volumetric electric field integral equation with the near field of the radio as the excitation field. Once the equivalent volumetric currents are determined, the efficiency and radiation patterns are found using these currents and the unperturbed free space current of the radio antenna.