文章信息/Info

Title:

Epsilon-Negative Materials:a Branch of Metamaterials

作者:

范潤華

（1. 上海海事大學(xué)海洋科學(xué)與工程學(xué)院材料系，上海 201306）
（2. 山東大學(xué) 材料液固結(jié)構(gòu)演變與加工教育部重點實驗室，山東 濟(jì)南 250061）

Author(s):

FAN Runhua

(1. College of Ocean Science and Engineering, Shanghai Maritime University, Shanghai 201306, China)
(2. Key Laboratory for Liquid�睸olid Structural Evolution and Processing of Materials (Ministry of Education),
Shandong University, Jinan 250061, China)

關(guān)鍵詞:

超材料; 介電常數(shù); 微波吸收; 電容器; 電介質(zhì)

Keywords:

metamaterials;  permittivity;  microwave absorption;  capacitor;  dielectrics

DOI:

10.7502/j.issn.1674-3962.2019.04.01

文獻(xiàn)標(biāo)志碼:

A

摘要:

介電常數(shù)是材料的基本物性參數(shù)之一,其值一直被認(rèn)為正。受超材料的負(fù)物性參數(shù)啟發(fā)，作者研究組提出導(dǎo)體/絕緣體隨機(jī)復(fù)合探索常規(guī)材料的“超常”性質(zhì)，建立了負(fù)介材料的原理框架和構(gòu)筑策略，形成了有別于其它超材料的一個特色分支。對于導(dǎo)體/絕緣體復(fù)合材料，導(dǎo)電相含量超過但仍然接近逾滲閾值情況下，絕緣基體中連通的導(dǎo)電相成為電感(L)功能體，射頻等離振蕩這一自由電子集體行為導(dǎo)致負(fù)介電；孤立的導(dǎo)電相則作為電容(C)功能體，并通過LC諧振影響負(fù)介電行為。逾滲復(fù)合材料為負(fù)介性能調(diào)控提供了豐富的手段，導(dǎo)電相可以是金屬、碳材料等不同類別，可以是顆粒、纖維、片層等不同形貌；絕緣體可以是樹脂，也可以是陶瓷。相對于主要建立在陣列結(jié)構(gòu)基礎(chǔ)上的超材料，負(fù)介材料是一個補(bǔ)充，豐富了超材料的內(nèi)涵。負(fù)介材料為電容器和電感器、微波吸收和衰減、天線等領(lǐng)域的選材用材提供了新的思路。

Abstract:

Dielectric permittivity, a fundamental parameter of materials, is generally considered to be positive for conventional materials. Inspired by the negative parameters in metamaterials, Fan and his co�瞱orkers focus on the negative permittivity of percolative composites consisting of conductive filler dispersed in the insulative matrix and pioneer the experimental and theoretical study on epsilon�瞡egative materials. When the content of conductive fillers is above but still near the percolation threshold in the conductor�瞚nsulator composites, the negative permittivity will be achieved by the low�瞗requency plasmonic state in the conductive percolative network with inductive character, while the frequency dispersion of negative permittivity can be effectively adjusted by the LC resonance due to the capacitive character of isolated conductive fillers. Percolative composites provide a more flexible method for the design and regulation of epsilon�瞡egative property because the conductive fillers have many choices in phases, metal or carbon, and in the morphology of sheet, fiber or particle. Moreover, polymer or ceramics can both serve as matrix. The epsilon�瞡egative materials have potential applications in electromagnetic attenuation, capacitor, microwave antenna, and wireless power transmission.