The conventional finite-difference time-domain (FDTD) method is efficient for microwave frequencies, but requires a large number of time steps for low frequencies. In this work, a hybrid Crank–Nicolson (CN) FDTD-SPICE method is applied to field-circuit analyses in low- frequency wideband problems. The unconditionally stable CN-FDTD method is used to give a rapid full wave solution by overcoming the Courant–Friedrichs–Lewy (CFL) condition that constrains the conventional FDTD method at low frequencies. The hybrid CN-FDTD-SPICE method can be used for simulating the interactions between modern electronic circuit systems and a 3-D structure supporting field radiation and interferences. It can greatly improve the computational efficiency over the conventional FDTD method at low frequencies because its time increment can be significantly larger. Three numerical examples are presented to verify the accuracy and efficiency of this hybrid method. Its CPU time is much shorter than that of the conventional FDTD-SPICE method. This CN-FDTD-SPICE method becomes increasingly advantageous when the radiation fields are required as the system integration continues to accelerate.

中文翻译：

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用于低频宽带问题的现场电路分析的混合CN-FDTD-SPICE求解器

常规的有限差分时域（FDTD）方法对于微波频率是有效的，但对于低频则需要大量的时间步长。在这项工作中，将混合Crank-Nicolson（CN）FDTD-SPICE方法应用于低频宽带问题中的现场电路分析。无条件稳定的CN-FDTD方法用于克服Courant-Friedrichs-Lewy（CFL）条件，该条件限制了低频下的传统FDTD方法，从而提供了快速的全波解决方案。CN-FDTD-SPICE混合方法可用于模拟现代电子电路系统与支持场辐射和干扰的3-D结构之间的相互作用。与传统的FDTD方法相比，它的低频增量可以大大提高，因为它的时间增量可能会更大。给出了三个数值示例，以验证该混合方法的准确性和效率。它的CPU时间比传统的FDTD-SPICE方法要短得多。当需要辐射场时，随着系统集成的不断加速，这种CN-FDTD-SPICE方法变得越来越有优势。