A Wideband Reflectarray Based on Single-Layer Magneto-Electric Dipole Elements With 1-bit Switching Mode
Wen Wu, Kai‐Da Xu, Qiang Chen, Toru Tanaka, Masaki Kozai, Hiroya Minami
Abstract
A single-layer wideband low-cost linearly polarized reflectarray with 1 bit magnetoelectric (ME) dipole as the unit cell is presented. The 180° reflection phase difference between the two states for the unit cell is realized by switching the ground-signal-ground (GSG) transmission line between “open” and “short” to the ground in the ME dipole structure. The corresponding numerical simulations of the reflectarray unit cell show that the bandwidth of the reflection phase difference within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$180^{\circ } \pm 20^{\circ }$ </tex-math></inline-formula> is more than 34% under both normal and oblique incidences. Moreover, the insertion loss is lower than 0.35 dB over the entire Ku-band benefiting from the concise phase shifting structure. Two static reflectarray prototypes for collimated beam at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta = 15^{\circ }$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi = 0^{\circ }$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta = 15^{\circ }$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi = 90^{\circ }$ </tex-math></inline-formula> are designed and fabricated. The measurement results of the reflectarray verify a great advantage of wideband performance, with over 32% bandwidth for 1.5 dB gain variation below the maximum value in both <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi = 0^{\circ }$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varphi $ </tex-math></inline-formula> = 90° planes.