Antenna factors of an off-resonant dipole antenna

Abstract

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.

Shortened dipole antenna factors by the reference antenna method at a finite separation

“…However, due to system limitations, such as the system dynamic range and the ground plane size, the AF calibration has to be implemented at a finite separation. To make the deviation of the measured AF by the TAM smaller than 0.1dB from that at an infinite separation (AF(  )), the antennas should be located at d > 19.25 m [9]. The The receiving antenna should be located in the far-field region of the transmitting antenna to avoid the mutual coupling between the antennas and to realize the plane wave illumination onto the receiving antenna.…”

“…Accordingly, the multiple reflections between the . (9) Note that the reflection coefficients are complex numbers. The complex reflection coefficients of the reference antenna and the AUC can be measured simultaneously with the SA measurements by using the VNA.…”