Time-Gating the Sources in Inverse Equivalent Source Reconstruction Problems to Eliminate Mutual Coupling Effects

Abstract

Inverse equivalent source reconstruction methods in antenna measurements are an efficient tool for field transformations and antenna diagnostics. Equivalent surface currents are reconstructed on a hull enclosing the antenna under test (AUT) from surrounding field measurement samples [1]. The obtained surface currents can be used to determine the radiated field at unmeasured locations or to verify the functioning of the AUT. For larger antenna structures, more measurement samples are required to find the correct surface currents. These surface currents are only valid for the exact environment in which the measurement samples are obtained [2]. Mutual coupling with undesired scatterers such as chamber walls or the antenna mounting alter the real current distribution on the AUT and therefore also the radiated fields. Solving the time-harmonic inverse problem can only retrieve the altered current distribution. However, knowledge about the pure free-space sources is usually desired.