An Improved Indirect Time-domain Technique on Lower Frequency Antenna

Measurements of radiation patterns of a lower frequency antenna by classical indirect time-domain techniques are error prone due to the narrow sweep bandwidth and lower range resolution. In order to solve this problem, a new correction technique of bandwidth expansion is incorporated into the measurement system. The technique set of the sweep bandwidth is much larger than the operating bandwidth and add the power reflected to transmission line to the frequency domain response by reflection coefficient. The antenna under test (AUT) has no reflection in the entire sweep bandwidth. Accurate radiation pattern can be obtained by using a Fourier transform and imposing a gating window. Simulation and experiment have verified the effectiveness of our method.