A Comparison of Cross-Polar Mitigation Methods for Reducing Polarimetric Biases

The adoption of polarimetric phased array radars as a next-generation alternative to dish antennas for weather observations shows significant promise. One of the main obstacles when calculating polarimetric variables with phased array radars is the increase in cross-polar contamination, which increases as the beam is steered away from the broadside. The CrossPolar Canceler (XPC) and pulse-to-pulse phase coding are two techniques that can help reduce this contamination. In this paper, both techniques are analyzed for the same array configuration. The comparison is performed using a simulated array of 1,600 patch elements (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\mathbf{3 2} \times \mathbf{3 2}$</tex> elements, square geometry) to estimate the biases in reflectivity factor (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Z_{\mathbf{h}}$</tex>), differential reflectivity (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$Z_{\text{DR}}$</tex>), and correlation coefficient (<tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\rho_{\text {hv }}$</tex>), and compare the improvement of each method with the base case. Preliminary results show that both techniques reduce the reflectivity bias, but phase coding works better than XPC for reducing the biases in differential reflectivity and correlation coefficient. Nevertheless, the performance of the phase coding technique is degraded as the intrinsic value of differential phase increases. Furthermore, the performance of XPC can be improved with proper H/V alignment calibration.