【摘要】 目的:探讨微波辐射屏蔽薄层材料的作用机制,特别是与辐射照射方向之间的依赖性,以期对电磁屏蔽材料做科学分类。方法:试验对筛选的多种微波屏蔽薄层材料,如加金属网结构的纤维编织材料、化学处理的微波防护布料、纳米碳涂膜金属板和动物体表组织材料等,在特定频段(9.3 GHz)的微波辐射场定向照射下,用微波分光计测定确定的微波束经界面作用后的空间强度分布特征。结果:未形成导电网的金属网结构编织材料并不具备明显的微波屏蔽功能;而化学处理的微波防护布料是强反射坪的屏蔽材料类;纳米碳涂膜金属板是透射窗型微波隐形材料;而动物体表组织材料等则为复合型的微波反射-吸收材料。结论:不同类型的薄层电磁辐射屏蔽材料,总体上都符合波的反射定律;但是,却在界面附近的近场区有着丰富的细节变化,利用结果可以大致对常见薄层材料的屏蔽防护作用分成强吸收窗型、强反射坪型和反射-吸收复合型等三类。初步分析认为,造成差异的基本机制可能与微波在材料表面诱发电磁波的二次发射能力有关。更多还原

【Abstract】 Objective: To explore the rule of shielding mechanism of microwave radiations by lamellar materials,especially the dependence upon the radiating directions and to classify the materials in science meaning.Methods: Some MW shielding lamellar materials elaborately chosen,including fiber & metal wires intertexture,MW exposure suit materials by chemical treatment,nano-carbon coated metal sheets and fresh pigskin,were exposed under the defined frequency(9.3 GHz) MW field and experimented the spatial distribution characteristics of MW field strength by a micro-spectrometer.Results: The fiber & insulated metal wires intertexture didn’t possess obvious MW-shielding function.The MW exposure suit materials by chemical treatment were strong reflecting plateau type MW-shielding materials.The nano-carbon coated metal sheets had a "transparent window" for a rather wide range of MW incidence angles and so they can be used as MW secret materials.As biological tissue material,the fresh pigskin treated was identified as a kind of complex MW absorbing and reflecting material.Conclusion: Although all the kinds of experimental samples exhibited the coherence with the reflection law to MW sheaf,there was lots of significant diversifying in detail nearby the interfaces.The experimental evidences might be helpful to classify EM shielding materials into three types.And it is recognized that the main cause for the obvious differences in mechanism may be related to the ability of secondary EM radiations induced upon the interfaces.更多还原