Multibeam Forming With Arbitrary Radiation Power Ratios Based on a Conformal Amplitude–Phase-Controlled Metasurface

Abstract

In this communication, we present a novel amplitude–phase-controlled metasurface (APCMS), which features a full <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\pi $ </tex-math></inline-formula> phase coverage and amplitude variation from 0 to 1 for transmissive waves. By alternately cascading three ultrathin printed circuit boards (PCBs) and two curved 3-D-printed substrates, the proposed APCMS is designed to be a cambered surface and can be applied to certain space-constrained scenarios. Different from phase-only controlled metasurfaces (MSs), with the ability to impart a new degree of freedom, we use the APCMS to construct a spatial power divider by superimposing multiple aperture fields assigned to amplitude weighting coefficients. As a proof-of-concept example, two quarter-cylindrical APCMS-based spatial power dividers are designed to generate equal-power and unequal-power triple-beam radiation patterns at different and same elevation angles, respectively. A prototype of an equal-power divider is fabricated and measured to verify the proposed strategy. The results show that upon illumination of a feed horn, the maximum difference among the realized gains of the three beams is less than 0.9 dB at 12 GHz. Their 3 dB gain bandwidths are 26.7%, 19.5%, and 23.3%. Our study holds potential applications in multibeam shaping and multiple target tracking systems.