The effects of a nearby biological body on the parameters of asmall hand-held transmitter operating in the HF band (3 MHz-30 MHz)

摘要

The effects of a nearby biological body on the efficiency and radiation patterns of a small hand-held radio operating in the HF band are determined by computer modelling. 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 on the antenna 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 used 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