Dual-Polarization 1-bit/Quasi-2-bit Low-Cost Programmable Metasurface With Merged Control Circuit

Abstract

We propose a low-cost programmable metasurface (PM) with distinct advantages of being 1 bit or quasi-2 bit, featuring dual polarization, and requiring fewer I/O pins. This design merges the control circuit and the microwave structure layout on a thin, single-layer printed circuit board (PCB). To achieve this, we transform the aperiodic control circuit into a periodic circuit by loading D flip-flops, which is further simplified by loading controlled current sources (CCSs). Based on the layout of the bias lines, a capacitive slot is added to form the microwave structure. Two PIN diodes are orthogonally surface-mounted to achieve dual-polarization characteristics. In unit arraying, D flip-flops are staggered to reduce I/O pins usage. The design can be easily extended to quasi-2 bit by stacking the PCBs. A <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times16\,\,1$ </tex-math></inline-formula> -bit PM is simulated, fabricated, and measured to verify this design. The simulation includes functions such as generating high-gain beams, multibeams, and electromagnetic (EM) waves carrying orbital angular momentum (OAM). The far-field patterns exhibited a ±60° scanning range, achieving a maximum aperture efficiency of 25%. This design introduces a simple, cost-effective, adjustable operating frequency, dual-polarization, 1-bit, or quasi-2-bit PM, with potential applications in communication, imaging, and sensing scenarios.