CPC G02B 1/002 (2013.01) [G02F 1/133606 (2013.01); G02F 1/133504 (2013.01); G02F 1/133541 (2021.01)] | 3 Claims |
1. A device, comprising:
a substrate layer; and
a sub-wavelength structure layer;
wherein:
the substrate layer is a material layer with a refractive index of 1 to 5 in a microwave frequency band;
the sub-wavelength structure layer comprises a plurality of square columnar elements arranged in a matrix period with equal period in row and column directions;
the square columnar elements comprise a magneto-optical material;
adjustment of phase and amplitude of a circularly polarized electromagnetic wave is achieved by changing the length, width and height of the square columnar elements, and thus the device attains a desired isolation and insertion loss at a center frequency f0;
parameters of the magneto-optical material are:
coercivity Hc≥1000 A/m; remanence Br≥1 kGs; a voigt parameter of a permittivity tensor or permeability tensor in a working frequency band≥0.01;
self-biased work state is achieved by utilizing the remanence, and a magneto-optical effect provides non-reciprocity;
a thickness of the substrate layer is L, the square columnar elements have a height of h, a length of w1 and a width of w2; the square columnar elements are arranged to form a matrix array with equal row and column periods p; the device size is D1×D2; the device responds to circularly polarized incident electromagnetic waves; dimensions of the device satisfy the relationship: w1≤10 mm, w2=0.75 w1−1.25 w1, h=w1−3 w1, p=3 w1−4 w1, L=1/2 w1−2 w1, D1=10λ0−15λ0, D2=10λ0−15λ0, λ0=c/f0, and c is a speed of light in vacuum; and
a thickness of the device is sub-wavelength; the device is magnetized only once; and a remanence direction is parallel to an incident electromagnetic wave direction.
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