Determination of the antenna factor of microwave antennas using the antenna impedance measurement

A newly developed antenna calibration method, named the antenna impedance method, was examined on its applicability for various microwave antennas. In the experimental calibration, the antenna impedance was measured above a small-sized metal plate (1 m × 1 m). It was concluded that the method could yield accurate free-space antenna factors for waveguides and LPDAs (log-periodic dipole array antennas) with an error around 0.3 dB or less. However, for a DRGA (double-ridged-guide horn antenna), the difference was increased to around 1.0 dB. It was found that a metal plate of a sufficient size is required for the calibration of broad beam antennas.