This paper discusses the Smith Chart, used by RF, antenna, and broadcast engineers between roughly 1940 and 1980 for the design of matching circuits. Use of the chart was time-consuming and error-prone, however, and numerical methods such as the Real Frequency Technique were widely used as alternatives when computers became more readily available. Nonetheless, the Smith Chart never lost popularity as a design tool in many European and Asian countries, and in the 1990s, several new graphics-based Smith Chart software design tools emerged on the market.


The paper provides historical background and information about related design aids and software solutions available today.