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arXiv 0906.0495physics.class-phphysics.optics
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时变背景介质中的电磁辐射

Electromagnetic radiation in a time-varying background medium

Neil V. Budko

摘要:

给出了任意脉冲源入射均匀时变背景介质时的电磁辐射的解析解。在阻抗不变的情况下,得到了由时间的任意正函数描述的同步介电常数和磁导率的显式辐射公式。可以预期的是,这样的介质引入了显着的频谱偏移和时空调制,这是分析在这里的线性和指数的介质参数的时间变化。在变阻抗的情况下,获得的解决方案的四阶多项式时间依赖的介电常数。除了频谱偏移和调制之外,该空间均匀介质散射场,从而在接收器位置处引入因果回波。

英文摘要:

Analytical solutions are presented for the electromagnetic radiation by an arbitrary pulsed source into a homogeneous time-varying background medium. In the constant-impedance case an explicit radiation formula is obtained for the synchronous permittivity and permeability described by any positive function of time. As might be expected, such a medium introduces significant spectral shifts and spatio-temporal modulation, which are analized here for the linear and exponential time-variations of the medium parameters. In the varying-impedance case the solution is obtained for the fourth-order polynomial time-dependence of the permittivity. In addition to the spectral shifts and modulation this spatially homogeneous medium scatters the field introducing causal echoes at the receiver location.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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