论文标题
电磁学的Wigner-Smith时间延迟矩阵：具有材料分散和损失的系统
Wigner-Smith Time Delay Matrix for Electromagnetics: Systems with Material Dispersion and Losses
论文作者
论文摘要
Wigner-Smith（WS）时间延迟矩阵将系统的散射矩阵与其频率导数相关联，并引起所谓的WS模式，这些WS模式在与系统交互时会体验到定义明确的组延迟。对于由非分散和无损材料组成的系统，先前显示WS时间延迟矩阵由能量样密度的体积积分和校正项组成，这些矩阵以及校正术语构成了系统的指导，散射或辐射特性。这项研究将WS时间延迟矩阵的使用扩展到由分散和有损材料组成的系统。具体而言，它表明，可以通过以说明系统的分散性和损失性质的术语来增强先前派生的表达式来表达此类系统的时间延迟矩阵，然后进行转换，该转换将损失损失的影响从时间延迟延迟。分析和数值示例证明了新的配方再次允许构建频率稳定的WS模式，这些模式在与系统交互时会经历明确定义的组延迟。
The Wigner-Smith (WS) time delay matrix relates a system's scattering matrix to its frequency derivative and gives rise to so-called WS modes that experience well-defined group delays when interacting with the system. For systems composed of nondispersive and lossless materials, the WS time delay matrix previously was shown to consist of volume integrals of energy-like densities plus correction terms that account for the guiding, scattering, or radiating characteristics of the system. This study extends the use of the WS time delay matrix to systems composed of dispersive and lossy materials. Specifically, it shows that such systems' WS time delay matrix can be expressed by augmenting the previously derived expressions with terms that account for the dispersive and lossy nature of the system, followed by a transformation that disentangles effects of losses from time delays. Analytical and numerical examples demonstrate the new formulation once again allows for the construction of frequency stable WS modes that experience well-defined group delays upon interacting with a system.
