Ultra-wideband dual-polarized transmitarray antenna with Vivaldi elements

The implementation of an ultra-wideband (UWB) dual-polarized transmitarray antenna (TA) is presented in this paper. The proposed TA takes advantages of the UWB performance of Vivaldi array and the true-time-delay (TTD) characteristic of transmission line to overcome the inherent bandwidth limitations. First, a dual-polarized TA element featuring low transmission losses, high polarization purity, and linear TTD phase responses over 5-16 GHz is designed, where an improved high-impedance microstrip phase delay polyline is developed to enhance the transmitting efficiency. Then, in-band resonances caused by wire grid ground in the construction of dual-polarized TA aperture are carefully addressed. As a proof of concept, a prototype including 22 x 23 elements arranged in an egg-crate configuration is manufactured and measured. The experimental results show that the TA achieves stable radiation performance within the operating band.