Metamaterial Antenna Refractive Index Gradient
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Solution Overview
Problem
Conventional spherical lenses used in optics are bulky, sensitive to shape precision, and cause significant refraction, diffraction, and reflection of electromagnetic waves, leading to performance issues and energy loss.
Innovation Solution
A metamaterial with a curved surface where refractive indices decrease gradually with angle θ, allowing electromagnetic waves to exit in parallel, designed with man-made microstructures on a sheet-like substrate, and optionally featuring impedance matching layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a spherical lens is used to converge electromagnetic waves, then the lens can refract spherical waves into plane waves, but the lens becomes bulky and heavy
Solution Approach 1:
The patent changes the refractive index parameter from a constant value to a spatially varying distribution n(x,y,z) that follows a specific mathematical function. This continuous parameter change allows the lens to achieve the desired wave convergence effect while maintaining a flat, lightweight structure instead of requiring a bulky spherical shape
Solution Approach 2:
The patent transitions from a traditional spherical lens geometry to a flat lens structure by introducing a refractive index gradient in the thickness dimension. The refractive index varies continuously from the top surface to the bottom surface according to a specific function, enabling wave convergence in a planar configuration that is much thinner and lighter than a spherical lens
2Reliability
If a spherical lens with precise shape is used, then directional propagation can be achieved, but the lens requires high manufacturing precision and is sensitive to shape deviations
Solution Approach 1:
The patent replaces the requirement for precise spherical geometry with a controlled refractive index parameter distribution. By programming the refractive index to follow a specific mathematical function n(x,y,z), the lens achieves directional propagation control through material property variation rather than geometric precision, significantly reducing manufacturing difficulty
Solution Approach 2:
The patent applies different refractive index values at different locations within the lens thickness. Each point (x,y,z) has a locally optimized refractive index determined by the function n(x,y,z) = n0 - (n0-1)exp(-αz²), where α controls the gradient. This local quality variation enables precise wavefront control without requiring high global geometric precision
3Reliability
If electromagnetic waves propagate through a conventional lens, then refraction occurs, but serious interferences and losses are caused due to considerable refraction, diffraction and reflection
Solution Approach 1:
The patent uses a continuous refractive index parameter change from the top surface (z=0) to the bottom surface (z=d) according to the function n(x,y,z) = n0 - (n0-1)exp(-αz²). This continuous gradient eliminates abrupt interfaces where reflection and diffraction occur, allowing electromagnetic waves to propagate smoothly through the lens with minimal energy loss
Solution Approach 2:
The patent converts the typically harmful effects of refraction, diffraction, and reflection at interfaces into beneficial effects by using a continuous refractive index gradient. The gradual parameter change transforms what would be disruptive discontinuities into a smooth transition that guides waves efficiently, turning potential energy losses into controlled wave propagation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Significantly reduces refraction, diffraction, and reflection, improving the performance of the metamaterial and metamaterial antennas by easing interference problems and enhancing electromagnetic wave propagation.
Implementation Method 1
Each point on the curved surface to which the angle θ uniquely corresponds has a same refractive index. Refractive indices of the metamaterial decrease gradually as the angle θ increases. Electromagnetic waves propagating through the metamaterial exits in parallel from a second surface of the metamaterial.
Data Source
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AI summary
The present invention relates to a metamaterial and a metamaterial antenna. The metamaterial is disposed in a propagation direction of the electromagnetic waves emitted from a radiation source. A line connecting the radiation source to a point on a first surface of the metamaterial and a line perpendicular to the metamaterial form an angle θ therebetween, which uniquely corresponds to a curved surface in the metamaterial. Each point on the curved surface to which the angle θ uniquely corresponds has a same refractive index. Refractive indices of the metamaterial decrease gradually as the angle θ increases. The electromagnetic waves propagating through the metamaterial exits in parallel from a second surface of the metamaterial. By designing abrupt transitions of the refractive indices of the metamaterial to follow a curved surface, the refraction, diffraction and reflection at the abrupt transition points can be significantly reduced. As a result, the problems caused by interferences are eased, which further improves performances of the metamaterial and the metamaterial antenna.