Polarization conversion method and polarization converter based on artificial electromagnetic material

Abstract

The invention relates to a polarization conversion method based on artificial electromagnetic materials. Electromagnetic waves are controlled to be spread in the artificial electromagnetic materials which constitute a polarization converter by designing the structure of the artificial electromagnetic materials, thereby leading the relation of the transmission coefficients of an electric field in the different directions to achieve the conversion from one incident wave polarization state to another emergent wave polarization state in a plane which is perpendicular to the wave spread direction, the relation of the transmission coefficients needs to be met is as follows: if the spread direction of the electromagnetic waves is defined as an X axis of a three-dimensional rectangular coordinate, the electric field E is decomposed to two electric field components of Ey and Ez which are mutually perpendicular, E is equal to yEy plus zEz, the transmission coefficients of T<y> and T<z> of the electric field in the two directions which pass the materials that constitute the polarization converter meet the following conditions: 1) for the situation of converting the incident waves with any polarization state to the emergent waves with the linear polarization, the absolute value of T<y>\the absolute value of T<z> is equal to p multiplied by the absolute value of Ez\the absolute value of Ey; ang(T<y>) minus ang(T<z>) is equal to plus or minus n pai minus (ang(Ey) minus ang(Ez)); wherein, n is equal to 0, 1, 2,..., p is the tangent value of an included angle theta between the linear polarization direction of the emergent waves and a z axis, p is not less than 0 and not more than 1, ang(T<y>) and ang(T<z>) represent the relative phases of T<y> and T<z>, ang(Ey) and ang(Ez) represent the relative phases of Ey and Ez. The polarization conversion method has the advantages of low cost, low energy consumption, high efficiency and compact structure.

Description

technical field [0001] The invention relates to a method for realizing polarization conversion based on artificial electromagnetic materials, and a polarization converter realized based on artificial electromagnetic materials. Background technique [0002] The polarization state of electromagnetic waves and light is widely used in liquid crystal displays, radio frequency antennas and various radiation devices, satellite antennas and optical devices. Traditional polarization conversion methods and devices usually limit the transmission of one polarized wave and reflect the unwanted polarized wave; or split the wave into two beams with different polarization states, so one polarized wave can only carry Less than half the energy, and the process requirements and costs are high. In addition, the conversion between circularly polarized waves and linearly polarized waves can be achieved by using waveguides with tapered cross-sections. Used to achieve polarization conversion. Th...

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Problems solved by technology

The former has a large energy loss, while the latter has a small energy loss, but the outgoing wave with good polarization isolation requires high processing accuracy and is difficult to realize.

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