Reflection of Plane Wave from Multi-layered Dielectrics

Estimation of the reflection coefficients of plane electromagnetic wave from the dielectrics is well understood. However, there exists an enormous application of this fundamental phenomenon of electromagnetics in determination of thickness of dielectrics from the measured reflection coefficients. Such applications are very important in the development of sensors where there is no other undestructive technique to get the estimation of the thickness of layers. Such applications include estimation of thickness of asphalt and bitumen of the road, thickness of ash deposited by volcanic eruption, thickness of fat layer in human abdomen. Behaviour of multiple dielectric slabs in waveguide has been thoroughly investigated [1]. However, in actual situation, the multiple dielectric layers exist in free space or in contact with very thick dielectric. For simplicity, we shall investigate the reflection of plane electromagnetic wave from multiple layers of plane dielectrics at an arbitrary angle of incident.