Optimization of dual polarization phased array antenna and radar signal processing for weather applications

Abstract

Phased array radar (PAR) uses multiple antenna elements to electronically steer a beam in different directions without physically moving the antenna. This capability allows the radar system to rapidly focus and scan a particular volume of the atmosphere. This characteristic of PAR as well as the continuous technological advancements make it very lucrative for weather radar applications at S- and C-band. PAR faces various significant challenges such as the limited angular scan range of a single-faced PAR, variations in beam pattern characteristics such as gain, cross-polarization, and beamwdith with scan newlineangle, radio frequency interference (RFI) at operational frequencies and changes in the newlineaccuracy of measured polarimetric variables. Addressing these challenges is crucial newlinefor the large-scale deployment of PARs in applications such as tornado detection and newlineprediction, cyclone path determination, convective precipitation measurement, and newlinequantitative precipitation estimation. newline newlineThe aforementioned challenges can be divided into two groups: antenna hardware design modifications and signal processing modifications. Innovations in antenna newlinehardware design can enhance the angular scan range, reduce cross-polarization, and newlinemitigate RFI. Improving the antenna s angular scan range requires reducing interelement spacing. This inter-element space reduction results in a compact antenna array which scans for a higher angular range but the mutual coupling between antenna elements increases which in turn affects the cross-polarization performance of the phased array antenna. Another challenge that needs to be addressed is the RFI faced by radars operating at C-band due to multiple RF communication equipment being developed in that band. The signal processing aspect involves enhancing the accuracy of radar polarimetric variables using distributed beamforming.