Accurate gain measurement of horn antennas in the shortened far field

A measurement technique is described which is well suited for experiments in anechoic chambers to determine the far-field gain of two identical pyramidal horn antennas with an uncertainty of +or-0.1 dB. For this technique it is necessary to find out the location of the amplitude center of a horn for observation points within the far-field region. In addition, the amplitude center leads to the phase center in the 45 degrees plane of the radiation field.>