The tool provides a way to measure return loss given the load and source impedance. VSWR (Voltage Standing Wave Ratio) is a metric commonly used with antenna systems for ham or shortwave radio communication. VSWR is normally defined as a ratio with a 1:1 VSWR, indicating that there is an exact or perfect match between all antenna system elements

The tool provides a measure of reflection coefficient given source and load impedance (Zs and Zl). Reflection coefficient is a measure of energy transfer from source to load. The value is 1 when load impedance perfectly matches the source impedance.