A system-independent algorithm for phase center determination

Abstract

A system's phase center (PC) is an equivalent point behaving like an ideal, isotropic radiator from which spherical waves emanate. Ideally, the phase on a spherical surface in the far field of this point is constant. Determining the PC of an antenna system is a very challenging task important for many different applications like electromagnetic compatibility (EMC) testing, GPS or radar navigation systems. EMC testing especially relies on accurate knowledge about the PC location of the testing antenna. Particularly in EMC tests employing relatively small measuring distances (e.g. 1 m- or 3 m-tests) it is of the utmost importance to setup and maintain the correct distance between test antenna and equipment under test (EUT) for every test frequency while the PC location can change with frequency. Although a variety of methods to find PCs have been proposed in the past, there is still a lack of general methods, that are system-independent and apply to arbitrary antennas and radiating systems. With less effort, compared to other methods, the system-independent algorithm presented here is able to calculate precise PC locations from simulated or measured electric and magnetic field data. Accurate results can be achieved with small amounts of field data, ensuring practical applicability of the proposed method.