FDTD后时间步信号的外推与实现

Extrapolation algorithm of FDTD late time signals and its programming

根据一小段FDTD计算的时域信号，利用GPOF方法提取出组成该信号的各个复指数函数，通过将这些复指数函数相加构造出时域的信号函数，并利用它进行外推计算，以求得信号在后时间步的响应，这样比完全采用FDTD方法计算节省了大量的处理问题的时间。采用Visual Basic与MATLAB的MatrixVB联合编程的方法，编写了外推计算的程序，并将该程序应用到U形双频天线进一步优化设计中，使天线的模拟效率提高了3～6倍。

The generalized pencil-of-function（GPOF） method is used to extract the complex exponentials from the truncated time domain signal in finite difference time domain（FDTD） simulations. According to the superposition of these complex exponentials, the function of the time domain signal is formed, by which the remaining part of the signal is efficiently extrapolated without further FDTD execution, thus the time of computation can be saved greatly in comparison with pure FDTD calculation. To make implementation of extrapolation easy, a program package is developed by using the Visual Basic programming language and MatrixVB of MATLAB. The package is used to extrapolate the FDTD late time signals in the optimization design of the U-shaped dual-frequency antenna. The simulation efficiency of the antenna is improved by three to six times.