An Approach for In-Situ Scan Impedance Characterization of Phased Antenna Arrays

Scanned phased array antennas require active scan impedance determination and mitigation. Active scan impedance mismatch can cause main beam pattern deformation, and in the extreme case, scan blindness. This thesis addresses scan impedance determination by introducing a novel in-situ measurement architecture and associated mathematics for efficiently determining the real-time active scan impedance of arbitrary sized scanned arrays in the field. The in-situ nature of the proposed architecture reduces the need for large numerical simulation and/or estimation of scan impedance variations due to possible diverse antenna array placements in the field, where mutual coupling effects can change. Direct experimental characterization also enables direct validation of numerical simulation. The mathematics developed is for an M by N antenna array. The mathematical model was implemented in MATLAB and verified through simulation using CST Microwave Studio (MWS) for a two by two monopole planar antenna array. The mathematical model’s robustness has been tested by varying the inter-element spacing, and by experimental implementation.Sandia National LaboratoriesElectrical EngineeringMastersUniversity of New Mexico. Dept. of Electrical and Computer EngineeringChristodoulou, Christos G.Loui, Hung "Jacques"Gilmore, Mar