DIAGNOSTIC TOOLS FOR MULTIFEED ARRAY ANTENNAS

摘要

Diagnostic tools for the determination of the excitation coefficients of a multifeed antenna based on pattern measurements are extremely useful during a spacecraft antenna design. Due to the complexity of state of the art multifeed antennas, it is not straight forward to trace back to the location of possible error sources, if deficiencies or non-compliance's are detected during an antenna measurement campaign.rnTherefore a method was developed and tested at DSS which directly determines all effective excitation coefficients from pattern measurements.rnThe method approximates the measured composite array pattern by a set of computed element beam pattern, weighted by a set of unknown excitation coefficients. The resulting equation system is solved using the Method of Moments (MoM).rnThe tool was extensively tested at DSS. The accuracy obtained for the calculations of the coefficients was in the 2% range beeing compareable to the accuracy of Beam Forming Network (BFN) measurements using a network analyser.rnIn this paper the theoretical background of the method as well as some application cases will be described.