DESIGN AND IMPLEMENTATION OF A PHASED ARRAY ANTENNA FOR MULTI-MISSION APPLICATIONS

Abstract

Multifunction Phased Array Radar (MPAR) was defined to investigate the feasibility of integrating weather observation and air surveillance radars into a single network. Weather radars require dual polarization capability which may be also beneficial to aircraft characterization. Research activities have begun to identify challenges, mitigate risk, and demonstrate polarimetric technologies. Ten-panel, developed by MIT’s Lincoln Laboratory, was the first dual-polarized planar phased array demonstrator. Alternatively, a cylindrical polarimetric phased array radar (CPPAR) was developed at the Advanced Radar Research Center of the University of Oklahoma to resolve the intrinsic limitations of planar arrays in making accurate polarimetric measurements. The current CPPAR employs a frequency scanning patch array antenna. Since the radar’s performance would be the most important driver, the future operational CPPAR, suitable for long-range weather measurement, will utilize a new antenna with higher performance. It is the purpose of this research to propose a new dual-polarized phased array antenna for MPAR application. A crossed dipole antenna with sufficient operational frequency bandwidth is designed. A high polarization purity is achieved by using a group of efficient techniques in element scale. This element was modified to obtain a higher match between copolar beams. The modified element is utilized as an embedded element to form a cylindrical and a planar array antenna. It is demonstrated that suppressed azimuthal surface wave and consequently highly matched copolar beams can be achieved in a cylindrical array of proposed crossed dipole. In order to compensate for the electrical and geometrical asymmetry of the element, an imaged arrangement of the elements with respect to the center of the array is utilized. It is shown that a planar array of the modified crossed dipole, arranged in a specific configuration, proposes zero cross-polarization in the principal planes without increased side lobe problem. The experimental verification demonstrates that the proposed phased array antennas are promising candidates for multi-mission applications.