Topological Synthesis of Tree Shaped Structures Based on a Building Blocks Hypothesis

In this paper a new approach to evolutionary controlled creation of electronic circuit connection topology is proposed. Microwave circuits consisting of a tree like connection of ideal transmission lines are considered. Assuming that a reasonable number of transmission lines in a tree network ranges from 10 to 100, the number of connection combinations is immense. From the engineering practice comes the hypothesis that any device can be decomposed into some functional building blocks consisting of one to dozen transmission lines. The variety of linking combinations in a tree with a limited depth is confined to hundreds or thousands of shapes. Therefore we can decrease the dimensionality of research space, applying evolution to building blocks only. Evolutionary algorithm (EA) which processes simultaneously the population of λ functional blocks and population of ž circuits is proposed. A μ, λ selection scheme with tournament together with specific encoding of solutions, and custom operators is implemented. The μ, λ, α EA was tested on an example of the design of a microwave transistor matching circuit.