Overview of the current state of antenna modelling and development of modular software in Ukraine and the Former Soviet Union

We present basic ideas and give an example of implementation of the modular software developed in Ukraine and able to analyze and optimize complicated waveguide circuits and certain waveguide antennas with small computer memory and time resources. The software is based on the idea of efficient longitudinal segmentation, generation of sufficiently large modal bases of regular waveguides, and the use of mode-matching and generalized scattering-matrix techniques. It is presented on the broader background of an overview of the current state of antenna-modelling science and engineering in Ukraine and the Former Soviet Union.