PSTD-FDTD Analysis for Complex Irregular Fresnel Zone Plates

In the past, the Kirchhoff s diffraction integral (KDI) method was successfully employed to analyze the diffraction problem in simple Fresnel Zone Plate (FZP) design. However, for complex and irregular structured Fresnel Zone Plates, the Kirchhoff diffraction integral is no longer a good choice. Efficient full-wave analysis is thus needed for a complete 3D transient analysis. Owing to the large computation domain and huge unknowns of the Fresnel Zone Plate problems, which is typically 10lambda to 20lambda, to date, no full-wave analysis has been attempted. In this paper, an efficient PSTD-FDTD method was first developed and applied to the 3D transient analysis of the Fresnel Zone Plate problem. In this paper, both the classic Fresnel Zone Plate and the irregular Fresnel Zone Plate are analyzed with the PSTD-FDTD method. Its accuracy and efficiency are validated by comparing with the Kirchhoff s diffraction integral method.