Lockheed Martin Corporation, 100 Campus Drive, Newtown, Pennsylvania 18940, USA.
Nat Mater. 2011 Mar;10(3):216-22. doi: 10.1038/nmat2950. Epub 2011 Jan 30.
Metamaterials provide an unprecedented ability to manipulate electromagnetic waves and are an enabling technology for new devices ranging from flat lenses that focus light beyond the diffraction limit to coatings capable of cloaking an object. Nevertheless, narrow bandwidths and high intrinsic losses arising from the resonant properties of metamaterials have raised doubts about their usefulness. New design approaches seek to turn the perceived disadvantages of dispersion into assets that enhance a device's performance. Here we employ dispersion engineering of metamaterial properties to enable specific device performance over usable bandwidths. In particular, we design metamaterials that considerably improve conventional horn antennas over greater than an octave bandwidth with negligible loss and advance the state of the art in the process. Fabrication and measurement of a metahorn confirm its broadband, low-loss performance. This example illustrates the power of clever implementation combined with dispersion engineering to bring metamaterials into their full potential for revolutionizing practical devices.
超材料提供了一种前所未有的操控电磁波的能力，是新型设备的一项关键技术，其应用范围广泛，涵盖了能够突破光的衍射极限的平场透镜，到能够实现物体隐形的涂层。然而，超材料的共振特性导致的窄带宽和高固有损耗，引发了人们对其实际应用的质疑。新的设计方法旨在将人们认为的色散的缺点转化为增强器件性能的优势。在这里，我们采用超材料属性的色散工程来实现特定的设备性能，以覆盖可用带宽。具体来说，我们设计了超材料，在超过一个倍频程的带宽内，将传统的喇叭天线的性能大大提高，同时几乎没有损耗，并在这个过程中推进了该领域的技术发展。超喇叭的制作和测量证实了其宽带、低损耗的性能。这个例子说明了巧妙的实现与色散工程相结合的强大力量，这将使超材料充分发挥潜力，彻底改变实际应用中的设备。
