School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom.
Sci Rep. 2013;3:1903. doi: 10.1038/srep01903.
In the last decade, a technique termed transformation optics has been developed for the design of novel electromagnetic devices. This method defines the exact modification of magnetic and dielectric constants required, so that the electromagnetic behaviour remains invariant after a transformation to a new coordinate system. Despite the apparently infinite possibilities that this mathematical tool introduces, one restriction has repeatedly recurred since its conception: limited frequency bands of operation. Here we circumvent this problem with the proposal of a full dielectric implementation of a transformed planar hyperbolic lens which retains the same focusing properties of an original curved lens. The redesigned lens demonstrates operation with high directivity and low side lobe levels for an ultra-wide band of frequencies, spanning over three octaves. The methodology proposed in this paper can be applied to revolutionise the design of many electromagnetic devices overcoming bandwidth limitations.
在过去的十年中，一种称为变换光学的技术已经被开发出来，用于设计新型的电磁设备。这种方法定义了所需的精确磁导率和介电常数的修改，使得在转换到新的坐标系后电磁行为保持不变。尽管这种数学工具引入了看似无限的可能性，但自从它被提出以来，一直存在一个限制：操作的有限频带。在这里，我们通过提出一种全介电实现的变换平面双曲透镜来解决这个问题，该透镜保留了原始曲面透镜的相同聚焦特性。重新设计的透镜在跨越三个八度的超宽带频率范围内表现出高指向性和低旁瓣水平的工作特性。本文提出的方法可以应用于颠覆许多电磁设备的设计，克服带宽限制。
