Millimeter-Wave Conformal Transmitarray and Its Beam Scanning Property

This paper introduces an ultra-thin transmitarray composed of unit cell elements with three layers of identical square ring slots. The structure is characterized by a minimal thickness of 0.508 mm, which is equivalent to 0.04λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> at 25 GHz in free space. The design procedure for specific phase values of the element is developed. By integrating this element into a conformal radiating array, a peak gain of 20.9 dBi is achieved through simulation. Furthermore, the fixed beam conformal transmitarray is expanded to a beam scanning transmitarray. By moving the feedhorn to various positions along the Y-axis, the main beam of the conformal transmitarray can be adjusted within an angle range of ±24°.