Antenna factors of an off-resonant dipole antenna

An off-resonant antenna, such as a shortened dipole is widely used in electromagnetic compatibility measurements due to compactness. The antenna factor of the shorten dipole antenna is ordinary calibrated by comparing that of the standard antenna. However, considerable errors are introduced by applying this method with an insufficient separation due to the coupling with the transmitting antenna and the field distribution along the element. In the present paper, errors in calibrating the off-resonant dipole antenna by the reference antenna method are discussed for the successful measurement.