The challenge of polarimetric coupling in phased array weather radars is explained, along with the resulting requirements. For the first time, state-of-the-art mitigation techniques on the system, hardware and software level are discussed together along with their achievements and shortcomings. An outlook is made toward future developments and applications, including integrated weather sensing and communications.

A novel element polarization optimization and phase quantization technique is proposed for the low-cost synthesis of three polarizations from active phased arrays. The horizontally (H) and vertically (V) polarized element ports are optimally combined with a fixed phase shift between them. For algorithm demonstration, pattern constraints for H, V, and an arbitrary third polarization, left-handed circular polarization (LHCP), are embedded in the goal function in a 16 by 16 array. It is demonstrated that including the LHCP in the optimization significantly improves its gain and side lobe levels, compared to when it is not included, at the cost of a slight reduction in the gain of the H/V polarized patterns. The side lobe and cross-polarization levels of H/V polarized patterns remain similar.

The impact of cross-polar coupling and a finite available number of echo samples on the data quality of polarimetric weather radar data is investigated. A system model and a two-step simulation approach are proposed to simulate realistic time series of the received weather radar signals. The proposed simulation methodology is applied to a rainfall scenario to illustrate the data quality of two widely used weather radar measurement schemes. Through simulation of the bounds within which 90% of the resulting estimates fall, it is demonstrated that the finite sample size introduces deviations that limit the data quality, even in designs with low cross-polar coupling.