A Comparison of Planar and Cylindrical Configurations of Polarimetric Phased Array Radar for Weather Observation

Planar and cylindrical arrays are candidate antennas for future polarimetric phased array weather radars. A planar phased array is a matured technology and easy to fabricate but it has issues of polarization coupling and bias in polarimetric measurements as the beam steers off broadside; A cylindrical phased array has polarization orthogonality and can make azimuthal scan invariant measurements, but difficult to fabricate. Each of them has their own advantages and disadvantages.

In this work, antenna patterns of the array configurations are studied and compared for dipole, slot and patch elements. The element radiations are simulated with the HFSS (High Frequency Structure Simulator). To make un-biased polarimetric measurements, the radar systems need to be calibrated for each beam steering directions. Two possible calibration procedures: i) projection/correction matrix method and ii) polarimetric variable calibration are examined. The correction matrix method adjusts amplitude and phase of each element for the H and V polarization, whereas the polarimetric variable calibration corrects the polarimetric estimates such as ZDR and ρhv.