The study on geometry-specific antenna factor

Antenna factor AF is one of the main uncertainties of radiated electromagnetic interference EMI and normalized site attenuation SA. Antennas are often calibrated on a perfectly conducting ground plane, which introduces the influence of reflected wave and mutual coupling between the antenna and the ground. It is shown in this paper that AF under these effects differs from free-space antenna factor FS_AF. Errors will be brought to SA if AF is used incorrectly. The influence of AF on SA is focused in this paper. Results reveals that SA, computed by using geometry-specific antenna factor AF_GS, is capable of providing more accurate values than by using AF_FS if AF_GS is gained in the same geometry of SA procedure.