网络函数有理逼近的向量拟合法

Rational Approximation of the Network Function by Vector Fitting Algorithm

随着集成电路设计复杂性以及电路工作时钟频率的不断提高,互连与封装等寄生效应对电路的影响越来越大,产生了信号完整性问题。如何准确地对这些效应进行分析模拟,成为当前集成电路设计中非常重要的任务。在高频时,互连与封装的特性只能通过测量或电磁场的数值模拟给出一组不同频率点上网络函数的采样值。基于这些采样值通过有理逼近构造网络函数宏模型,继而实现电路的时域分析是实现这类电路模拟的关键,但在逼近过程中非常大的一个困难是随着阶数增高矩阵病态严重的问题。该文介绍了网络函数有理逼近的向量拟合法,该法可以对多端口网络进行高阶宽频的稳定逼近。

With the continuous increasing of the clock frequency of high - speed circuits, the signal integrity analysis due to the requirement of assessing the effects of the parasitic structure on the performance of the circuits has become an indispensable step in the design. At very high frequencies, interconnects and packages can only be characterized by a set of sampled data from measurements or electromagnetic simulations over the frequency of interests. In order to accomplish the signal integrity analysis in the time - domain, it is necessary to construct a rational approximation based on these sampled data. This paper describes an excellent algorithm- - the vector fitting algorithm to realize the rational approximation of the multipert network function. It can realize the rational approximation with higher order and wider frequency range steadily.