Spice Model Generation from EM Simulation Data Using Integer Coded Genetic Algorithms

In the electronics industry, circuits often use passive planar structures, such as coils and transmission line elements. In contrast to discrete components these structures are distributed and show a frequency response which is difficult to model. The typical way to characterize such structures is using matrices that describe the behaviour in the frequency domain. These matrices, also known as S-parameters, do not provide any insight into the actual physics of the planar structures. When simulations in the time domain are required, a network representation is more suitable than S-parameters. In this research, a network is generated that exhibits the same frequency response as the given S-parameters whilst allowing for a fast and exact simulation in the time domain. For this, it is necessary to find optimum component values for the network. This is achieved in this work by using an integer coded genetic algorithm with power mutation. It has been shown that the proposed method is capable of finding near optimal solutions within reasonable computation time. The advantage of this method is that it uses small networks with fewer passive components compared to traditional methods that produce much larger networks comprising of many active and passive devices.