Time domain analysis of antenna return loss

We evaluate reflection coefficients of antennas based on time domain analysis with a sampling oscilloscope. The return losses of antennas were extracted by the Fourier transformation of reflection pulses from antennas with respect to the incident pulse signals. The three-error terms, which are commonly used for the correction of a microwave network, were determined using a 3.5 mm calibration kit. The reflection coefficients of antennas were compared with those measured with a commercial vector network analyzer.