Spatial Polarization Characteristics of Wide-angle Scanning Slot Phased Array

Antenna polarization states always varied with scan direction, a new concept of spatial polarization characteristics of antenna is defined in this thesis. Phased-array behaves distinct property compared to mechanically-scanned antenna. The wave-guide slot phased array is used in this paper to study the polarization property with wide angle scan in airspace. Theoretical analysis and simulation proved that the lobe property and polarization changes not much in the case of small azimuth and elevation scanning angle. However, there is dramatic increase of cross polarization component in the main lobe with wide scanning angle. This characteristic can be applied to measure the target polarization scattering property in phased array radar searching stage. Based on the single polarized radar antenna, a novel polarization scattering matrix (PSM) measurement method is proposed by sufficiently utilizing the inherent polarization property of antenna which is not constant but a function of antenna's spatial scanning direction. Two orthogonal polarization channels are not required in this method. Just by using the prior knowledge of antenna polarization characteristics and improving the signal processing mode of received radar signal, the PSM of target can be obtained.