Determination of gain for pyramidal-horn antenna on basis of phase center location

The phase center location is used to determine the gain for horn antennas using the three-antenna method. The phase center of a pyramidal-horn antenna in the 18 to 26.5 GHz frequency range was calculated using the finite integration method, and then the gain was measured by using the distance between phase center locations obtained from this calculation. The measured results of the gain on the basis of the phase center location were in good agreement with the theoretical values. The uncertainty (k = 2) of the measurement was 0.13 to 0.16 dB in the given frequency range.