A Low‐Scattering Conformal Transmitarray Antenna Based on an Absorptive Metasurface

Reducing scattering of large aperture antenna is crucial and challengeable in many communication and military systems. In addition, in numerous application scenarios, antennas are required to be integrated with conformal platforms. In this article, a conformal transmitarray with a low scattering‐signature is proposed. To overcome the difficulty of realizing curved structures using the traditional printed circuit board technology, an all‐metal phase shifting component with adjustable transmission phase response is designed. In the meanwhile our proposed phase shifting component is based on cross‐polarization conversion, which can avoid stacking multiple metallic layers to achieve a thin profile. A transmitarray aperture is composed of these all‐metal elements which then implemented for beam collimation. Furthermore, a lossy layer based on an ultra‐thin substrate is cascaded with the conformal structure to form an absorptive metasurface‐based transmitarray to absorb scattered waves. As a result, gain enhancement is achieved within the antenna's operating band with a peak gain of 21.59 dBi with a maximum aperture efficiency of 46.7%, while a significant scattering reduction is achieved at the antenna's out‐of‐band frequencies simultaneously.