A Broadband Low-Profile Dual-Circularly Polarized Reflect-Array Based on a Single-Layer Microstrip Patch for Ka-Band Application
Xi Wang Dai, Yu Hui Zhang, Weiliang Yu, Leilei Liu, Guo Qing Luo
Abstract
A broadband low-profile dual-circularly polarized (dual-CP) reflect-array (RA) cells covering both K- and Ka-bands is presented in this article. As an anisotropic impedance surface, the functional layer is designed based on a multi-resonant structure and printed on a substrate with a thickness of 0.762 mm. The circuit is composed of an elliptical ring, arc-shaped and rectangular metal microstrip lines. The air layer between the functional layer and the metal plate can effectively extend the cell bandwidth (BW), and the overall profile is 1.8 mm. The dynamic phase and Berry phase can be adjusted by changing the size of the arc-shaped microstrip lines and the rotation of the cells. The diffraction results show that the phase of left-handed (LH) circularly polarized (CP) and right-handed (RH) CP waves can be controlled independently and reflected by high purity with the cross-polarization BW of 64% (19.72 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim $ </tex-math></inline-formula> 38.44 GHz). A dual-CP RA with 1013 cells is designed to realize reflect beams at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta $ </tex-math></inline-formula> = −20° for LHCP wave and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta $ </tex-math></inline-formula> = 15° for RHCP wave at 30 GHz. Furthermore, the 3 dB gain BW can cover the Ka-band and is expected to be used in wireless and satellite communication systems.