Comparison between the Fields Modeled by a Circular Cylinder and a Screen in the Transition Region

This paper proposes an additional term between the fields modeled by a dielectric circular cylinder and an absorber screen, based on the uniform theory of diffraction (UTD) in the transition region. In the lit side of the transition region, the additional term is derived from the difference between the reflection from a dielectric circular cylinder and the diffraction from an absorber screen. In the shadowed side of the transition region, the additional term is derived from the difference between the creeping diffraction from a dielectric circular cylinder and the edge diffraction from an absorber screen. The proposed model is validated by numerical simulations at a high frequency. Through the proposal, we clarify the contribution of the Fresnel zone number and boundary conditions (i.e., the surface impedance and the polarization) to the scattered field.