Study of Metamaterial Configuration and its Applications for Frequency Selective Shielding Screen and Radome

讨论了金属棒阵列作为超材料或人工设计材料的电磁特性，并将其主要应用于频率选择屏蔽屏和天线罩材料。杆的共振发生在特定的频率，其波长近似等于杆长的两倍。金属棒阵列薄片的介电常数ε_r=ε_r ′-jε_r”是假设薄片是均匀的时的平均介电常数，其表现出由金属棒谐振引起的频率色散。在低于谐振频率的频率处，由于金属棒的极化，f_0，ε_r'变高。介电常数在f_0处迅速减小，在高于谐振频率的频率处，ε_r'变为负值。虚部ε_r”在f_0处最大。作为磁性材料，考虑磁性金属的微粒的混合材料， ...更多信息 实验证实它们的介电常数几乎为零。金属棒排列的薄片的透射系数在f_0处最小。频率选择性EM波屏幕由两个或多个金属棒对齐的片材制成，在它们之间具有间隔材料。实验证实了它们的屏蔽性能，并讨论了这种材料的另一个应用领域--吸收体。作为吸波材料，金属取向片的一个关键特性是ε r'在f_0附近迅速减小，这导致片输入阻抗的电抗X发生相反频率的变化，即dX/dw< 0。在常规材料中，X的频率特性总是dX/dw> 0，这就是福斯特电抗定理。由于金属棒排列片和常规电介质片的频率变化彼此相反，所以当这些片被层压时，可以使输入阻抗的频率变化最小化。基于这一思想，人们研制出了宽带吸波材料，目前已开始应用的有杆排列板的选频屏蔽屏和宽带吸波材料。少

The electromagnetic properties of finite-length metal-rod array sheets are discussed as metamaterial, or artificially designed material, and as their chief uses, frequency selective shielding screen and radome materials are investigated.The metal rods are periodically aligned on a thin dielectric sheets. The resonance of the rods occurs at specific frequency whose wave-length is approximately equal to double the rod length. The metal-rod array sheet permittivity,ε_r=ε_r'-jε_r", which is a average permittivity when the sheet is supposed to be homogeneous, shows frequency dispersion by the metal rod resonance. At frequencies lower than the resonant frequency, f_0,ε_r' becomes high due to the polarizations of the metal rods. The permittivity decreases rapidly at f_0, and at frequencies higher than the resonant frequency, ε_r' becomes negative. The imaginary part, ε_r", becomes maximum at f_0. As magnetic materials, hybrid materials of fine particles of magnetic metals are considered, and … More experimentally their permittivity was confirmed to be almost zero.The transmission coefficient of the metal-rod aligned sheet becomes minimum at f_0. The frequency selective EM wave screens are made with two or more metal-rod aligned sheets with spacing materials between them. Their shielding properties are experimentally confirmed.As one of the another applications of this material, absorber is discussed. As absorbing material, one of the key properties of the metal aligned sheet is the rapid decrease of ε_r' around f_0, which leads to the opposite frequency change in reactance X of the sheet input impedance, that is, dX/dw< 0. In conventional material, the frequency property of X is always dX/dw> 0, which is known as Foster's reactance theorem. Since the frequency changes of the metal rod aligned sheet and conventional dielectric sheet are opposite each other, it is possible to minimize the frequency change of input impedance, when these sheets are laminated. Based on this idea, the wide band absorber is achieved.The frequency selective shielding screens and the wide band absorbers, both made of the rod aligned sheet, are now in process of coming into use.. Less