Conformally Reconfigurable Transmitarray Antenna with Adjustable Curvature Using Asymmetrical Structure Printed on Thin Substrates

In this paper, a novel 1-bit cylindrical conformal reconfigurable transmitarray (CRTA) antenna with beam scanning and adjustable curvature is presented. To begin with, a thin reconfigurable transmissive unit cell that adopts an asymmetrical structure with dipole receiving and slotted patch transmitting with a thickness of 1.096 mm (0.0548λ0 at 15 GHz) is proposed. The phase of the unit cell is controlled by adjusting the on-off of the two diodes loaded on the receiving dipole to control the direction of the surface current. Furthermore, a cylindrical CRTA with electronic beam scanning ability is designed based on the proposed unit cell. A 12 × 20 prototype is manufactured and measured with a peak gain of 20.33 dBi at 15 GHz, an aperture efficiency of 15%, a 3-dB gain bandwidth of 6.3%, and a 1-dB gain bandwidth of 5.2%. The far-field beam scanning ability at different curvatures is experimentally proved, with a beam scanning range covering ±50° and a scan gain loss of around 3 dB. The proposed cylindrical CRTA with adjustable curvature has a larger application scenario in future wireless communications.