Effectiveness of a second order CPML absorbing boundary condition within the periodic FDTD method

The analysis of periodic structures is of great interest for engineers and scientists in a variety of applications. EMC design, antenna design, photonics, and LO design are examples of such areas. In previous works, it has been shown by these authors and others that such analyses may be accurately accomplished in the frequency or time domain. While previous works have been successful for a variety of problem scenarios, time domain implementations suffer a loss of accuracy at very low frequencies due to a breakdown of perfectly matched layer (PML) performance. In this paper, the authors demonstrate the split-field periodic FDTD method where convolutional PML (CMPL) has been employed to improve the deficiencies in the previous methods..