A simple quasi-static model applicable to a wide class of wire media is developed that explains strong non-locality in the dielectric response of wire media in clear physical terms of effective inductance and capacitance per unit length of a wire. The model is checked against known solutions and found to be in excellent agreement with the results obtained by much more sophisticated analytical and numerical methods. Special attention is given to suppression of the spatial dispersion effects in wire media.
Current-modulation annealing to control microwave permittivity in composites with melt-extracted microwires
研究了采用电流调制退火(CCMA)技术制备的CoFeBSiNb微丝/环氧树脂复合材料的微波性能。当外加磁场增加时,我们观察到含有退火25 mm Nb掺杂微丝的复合材料样品的有效介电常数谱中的共振峰的位移。这一观察结果与厚微丝的吸收主导阻抗和铁磁共振现象是一致的。结果表明,CCMA是一种合适的技术,以释放内部残余应力。因此,对于含有少量Nb的样品,我们观察到CCMA允许我们抑制在含有铸态线材的样品中观察到的高频共振峰。然而,对于含有大量Nb的样品,尽管进行了CCMA处理,高频峰仍然存在。在这种情况下,在介电常数谱中的双峰特征的观察归因于共存的非晶相和少量的纳米微晶分布在导线表面。然而,由于长(35 mm)和短(15 mm)的铸态导线和不完美的导线-环氧树脂键合的大的静磁能,可以检测到的谐振峰和特征双峰的介电常数谱没有移动。总体而言,CCMA出现作为一个有前途的策略,以控制微波介电常数的复合材料与熔融提取的微丝。
Generalized two-body self-consistent theory of random linear dielectric composites: an effective-medium approach to clustering in highly-disordered media
Additional Boundary Conditions for Nonconnected Wire Media
根据我们最近的工作[New J. Phys. 10,053011,(2008)],在这里,我们证明了由于强非局部效应,附加的边界条件是必不可少的非连接线阵列使用均匀化方法来表征电磁波的反射。基于简单的物理考虑,我们推导出额外的边界条件的情况下,导线介质是相邻的电介质或导电材料,并证明,在无损的情况下,这样的边界条件确保守恒的功率流。结果表明,附加边界条件的数目与单胞中金属丝的数目有关。我们说明了新的边界条件的应用程序,几个配置与实际利益。