In electrical engineering, impedance is the ratio of voltage to current with the consideration of phase angle. According to Ohm’s law V= IR, where V – voltage, I is the current and R is the resistance of the network. In RF, the idea of impedance matching is to equalizing the source and load impedance for maximum power transfer. Impedance is represented as Z and is complex than just the resistance of the network. In simple explanation, impedance matching is to making source and load impedance as similar as possible in order to minimize losses.
Smith chart is a chart representation of impedance and admittance grid developed by Philip Smith in Bell’s radio research lab during 1930s. Since then Smith chart is widely popular among electrical and electronic network engineers to solving problems and illustrate a complex network condition. Since the early stages of network analyzer, Smith Chart is one of the most important format to show the reflection of individual ports and easy to figure out mismatch in the network.