The resistance of capacitance and inductance to alternating current in a circuit is collectively called reactance. The blocking effect of capacitance on alternating current in the circuit is called capacitive reactance, and the blocking effect of inductance on alternating current in the circuit is called inductance. Impedance is usually represented by Z, which is a complex number, and called actual resistance while virtually called as reactance. In circuits with resistance, inductance, and capacitance, the resistance to current flow in the circuit is called impedance. Simply speaking, it is similar to a mathematical table, and the value of the reflection coefficient is known by searching.įirst, you need to understand what the impedance of a resistor, capacitor, and inductor is.

Some graphs are expressed in admittance values, which can be rotated 180 degrees from the impedance version above. The numbers on the sides of the graph represent the angle (0-180 degrees) and wavelength (from zero to half wavelength) of the reflectance. The edge of the graph represents the length of the reflection coefficient of which is 1, which is 100% reflection. The middle point of the graph (1+j0) represents a matched resistor value (ZL), and its reflection coefficient value will be zero. Resistance, where upwards are positive numbers and downwards are negative numbers. The circular line in the chart represents the real value of the electrical impedance, that is, the resistance value, and the horizontal line in the middle and the lines radiating upward and downward represent the imaginary value of the electrical impedance, which is generated by the capacitance or inductance at high frequencies. Among them, ZL is the load value of the line itself, and Z0 is the characteristic impedance (intrinsic impedance) value of the transmission line, usually 50Ω is used. That is, S11 and ZL in the S-parameter are the normalized load value ZL / Z0. Where Γ represents the reflection coefficient of its line

The basics of the Smith chart lie in the following formula. Smith once said, “When I can use a slide rule, I’m interested in graphically representing mathematical relationships.” The chart was invented by Phillip Smith in 1939 while working at RCA in the United States.

How inductance moves on a smith chart