【作者】 王晓晓；

【导师】 王政平； 秦世明；

【作者基本信息】 哈尔滨工程大学 ， 光学， 2007， 硕士

【摘要】 随着现代科学技术的发展，吸波材料在军事以及民用领域的应用显得越来越重要。吸波材料研制的主要目标是增加材料的吸收以使得吸波体结构更轻、更薄、吸收性能更好。理论和实践都指出只有电磁参量匹配时，吸波体在工作频段才会有较为理想的吸收性能。前苏联科学家Veselago于1968年提出了介电常数和磁导率都为负值的左手材料的设想，并预言了在其中传播的电磁波的电场、磁场和波矢量满足左手关系，故称其为“左手材料”。2001年该思想被实验证实。当电磁波在“左手材料”中传播时，将会表现出一系列奇异的电磁特性，如负折射、反多普勒效应、逆Cerenkov辐射等。作者的尝试性工作结果表明：将左手材料与常规右手吸波材料结合形成新的人工左右手材料吸波体时，吸波体的反射损失增加，吸收频带变宽。表明左手材料有望成为制备吸波性能良好的吸波体的材料之一。本文提出了四种含左手材料的吸波体结构：空气／左手介质／金属的单层结构、空气／左手介质／右手介质／金属的双层结构、空气／右手介质／左手介质／金属的双层结构、空气／左手介质／左手介质／金属的双层结构。利用传输矩阵法从理论上分析了吸波体结构最佳吸收时的电磁参量取值规律，利用遗传算法结合计算机仿真对这四种结构进行了优化设计，并研究了吸波体结构在8～12GHz频率范围内的吸波性能，考察了左手材料各个参量变化在8～12GHz频率范围内对吸波性能的影响。研究结果表明：四种吸波体结构中，左-右手材料双层吸波体的吸波性能最佳：双层吸波体中，左手材料电磁参量变化对吸收曲线的影响在参量不同取值范围内有不同的变化趋势，而且这种变化和右手材料取值有关；本文研究的吸波体(左-左手结构除外)中，左手材料层厚度增大，吸波体的吸收峰向低频方向移动。目前，在吸波材料与吸波体结构设计中引入左手材料的研究结果尚罕见报道，希望本工作能为左手材料或吸波材料研究领域的学者提供参考。更多还原

【Abstract】 With the development of modern technology, microwave absorbing materialsare becoming increasing important in both military and civil application fields.The main goal in the wave-absorbing materials research area is to increase theabsorption of the materials so that let the stealth structures be lighter, thinner andmore effective. Both theoretical and experimental evidences show that theabsorber will have better wave-absorption properties at the working frequency ifsuitable electromagnetic parameters’ combination is formed, which is called thatthe parameters are matched.In 1968, Ex-Soviet Physicist Veselago reported his theoretical study results ofthe electrical dynamic properties of the medium with both negative permittivityand permeability and named this kind of material as left-handed material(LHM),and predicted that the wave vector (?), the electric field vector (?), and themagnetic field vector (?) in this material will form a left-handed system. In2001, this idea was experimentally verified by D.Smith, etc. Whenelectromagnetic wave propagating in the LHM, there will be some magicalphenomena, such as negative refraction, reversed Doppler effect and reversedCherenkov radiation etc.Our research results predict that when LHM is combined with conventionalRHM to form a LHM-RHM double-layer structured absorber, the reflection lossof it will be increased and the absorbing band will be widened. This indicatesthat the LHM is hopeful to be one of the wave-absorber composing materials,which has better wave-absorption properties.In this paper, four wave-absorber models containing LHM are proposed,including air/LHM/metal, air/LHM/RHM/metal, air/RHM/LHM/ metal andair/LHM/LHM/metal structures. The valuation laws of electromagneticparameters for the aim that absorber has better absorbing properties aretheoretically analyzed using a transfer matrix method (TMM). The structures’parameters are optimized employing a genetic algorithm. The absorbing properties of the four absorbers mentioned above and the effects of the LHM’sparameters in each absorber on the wave-absorption properties in the frequencyrange from 8GHz to 12GHz are investigated and simulated using a transmissionline model.The results show that the air/LHM/RHM/metal structure has the bestabsorbing property among four absorber structures; among the 3 double-layerabsorbers, the influences of LHM’s electromagnetic parameters on the absorbingproperties have different varying trends, which is relative to the valuation ofRHM’s parameters, in different parameter valuations; as the increasing of theLHM’s thickness, the peak values of the absorption curves will change and thecorresponding frequency will also move towards lower frequency directions inthe absorbers(except LHM-LHM structure).There is few report about LHM used in absorbing material or absorber designareas can be found. Therefore, it is hoped that this work might be somereferences for the researchers working in the LHM or wave-absorbing materialsfields.更多还原