Novel method to measure the gain of UHF directional antennas using distance scan

A novel antenna gain measurement method is described which uses power transfer values that are measured while varying the distance between two antennas (Distance Scan). It can be executed with simple means and is cost-effective. The Distance Scan method yields derived free space antenna gain values if a calibrated reference antenna is used and can be combined with the Three Antenna Method to obtain absolute antenna gain values. The method is demonstrated with the antenna gain measurement of three 12 element Yagi-Uda antennas and two 15 element Log-Periodic Dipole Antennas (LPDA's) on 8 frequencies. The measurement results of the LPDA's are compared with values obtained by external calibration, confirming the validity of this method.