Realization and Analysis of Low-Loss Reconfigurable Quasi-Periodic Coding Metasurfaces for Low-Cost Single-Beam Scanning

Abstract

The development of metasurfaces from periodic designs to quasi-periodic ones, and eventually into reconfigurable periodic forms has significantly enhanced their capabilities. This article explores reconfigurable quasi-periodic metasurfaces (RQPMSs)—the latest generation of metasurfaces comprised of multiple elements. The phase quasi-periodic design plays a crucial role in suppressing symmetrical beams from 1-bit metasurfaces under normally incident plane waves. Three quasi-periodic forms were discussed to investigate the single-beam scanning capabilities of the RQPMS. Two types of low-loss 1-bit elements with a 90 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> phase difference were designed using an interdigitated structure. The maximum loss of elements is only 0.81 dB within the range of 9.25–11.00 GHz. A random arrangement RQPMS was constructed to confirm single-beam scanning effects. Experimental results demonstrate that the RQPMS can perform single-beam scanning from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> to 50 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\circ}$</tex-math> </inline-formula> while experiencing scattering loss (SL) less than 73% of the traditional 1-bit MS and sidelobe levels (SLLs) lower than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-$</tex-math> </inline-formula> 8.43 dB. The RQPMS uses only half the amount of diodes compared with traditional 2-bit metasurfaces, thereby simplifying design complexity and minimizing the implementation costs of the MS antenna. The successful implementation of phase quasi-periodic design validates the advantages of the concept of RQPMS and suggests its potential for extension to other parameters such as amplitude quasi-periodicity.