A Broadband Dual-Polarized Reconfigurable Transmitarray With Sum and Difference Beam-Steering Capabilities

This study presents a dual-polarized reconfigurable transmitarray (DPRTA) employing a receive-transmit mechanism for 2-D beam-steering and sum-difference (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Sigma -\Delta $ </tex-math></inline-formula>) beamforming control. A closed-stepped radiating structure with integrated p-i-n diodes is designed as the active receiver layer, complemented by a defective-arm passive structure in the transmission layer, jointly achieving 1-bit phase transition. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$4 \times 4$ </tex-math></inline-formula> dual-polarized (DP) aperture-coupled array along with microstrip <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Sigma -\Delta $ </tex-math></inline-formula> comparators is engineered to serve as the feed for monopulse functionality. To validate the design, prototypes of the DPRTA and the monopulse feed antenna (MFA) are fabricated and tested. Measurement results demonstrate that the proposed DPRTA is capable of achieving ±60° DP beam scanning with a peak gain of 21.1 dBi, corresponding to an aperture efficiency of 24.8%. Furthermore, it is verified that the proposed DP monopulse transmitarray can realize the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Sigma -\Delta $ </tex-math></inline-formula> beam steering from 0° to 30°. The DPRTA-based monopulse antenna offers advantages, such as low cost, lightweight construction, and straightforward manufacturing, promising innovative prospects for DP monopulse radar applications.