Design of a ultra broadband and wide scan radiator for a dual-polarized 6:1 frequency band array

The development of a radiating element for use in a dual polarized array with a frequency ratio of 6:1 and a conical scan of /spl plusmn/45/spl deg/ is described. The type of element employed is the ridge parallel plate element, which has been shown to possess a low cross-polarization property (Toland, B.T. and Chan, K.K., ANTEM 2002, Int. Symp on Antenna Tech. & Applied Electromagnetics, p.372-5, 2002). In the diagonal plane, the cross-polar level is typically 20-25 dB below the copolar peak within the scan volume, rising to 15 dB below at the high end of the frequency band. Such performance is superior to that of the printed crossed Vivaldi or notch clement. Further, the form of the element, which is entirely metallic, is particularly suited to a low loss, lightweight but rigid implementation of the array. Measured results of the element in an array environment are given.