Design of Tightly-Coupled-Dipole Transmitarray for Broadband CATR Application

In this paper, a wideband transmitarray antenna based on tightly coupled dipole is proposed for CATR (compact antenna test range) application. The transmitarray antenna is composed of a wideband feed antenna and a wideband transmission metasurface. The feed is an improved ultrawide band Vivaldi antenna. The wideband transmission metasurface consists of 30×15 cells, each of which consists of a tightly coupled dipole antenna and parallel metal lines. The concept of equivalent delay distance is introduced to design the transmitarray. To validate the design, a prototype operating from 3 to 9 GHz are fabricated and measured. Good agreement between simulated and measured results is observed. The measured results show that the antenna has a stable radiation pattern in the operating frequency band. The antenna gain is from 13.9dB to 22.2dB, and the aperture efficiency is greater than 21%. This can also hopefully be used for CATR based on its near-field properties.