Smith Chart Graphically solves the following bi-linear formulas Note: works for admittance too. Just switch sign of
Smith chart is the interior of the unit circle in the complex plane 45° | |=1/2 Example: Same length Re[ ] Im[ ]
Find Z L given Note: ZLZL Z eq Find real and Imaginary parts:
Curves of constant real part: R
Curves of constant imaginary part: X
45º | |=1/2
What is Z eq at l= /4 from the load? 45° | |=1/2 ZLZL Z eq
2 m Z L = (70+j50) f = 5 MHz Z 0 = 100 v= 10 8 m/s Z eq = ? Method 1: Sample Problem: find Z eq
Z L / Z 0 = (70+j50)/100 Z L / Z 0 = (.7+j.5) Move.1 toward generator Z eq / Z 0 = (1.6+j.65) Method 2: Smith Chart
Standing Wave Problem 1 m Z L = ? V max = 20m, Z 0 =100 VSWR= j1.3 Z L =170+j130 l max
l=? m Z L = (140+j130) f = 5 MHz Z 0 = 100 v= 10 8 m/s Y s = ? Z L /Z 0 = (1.4+j1.3) Y L /Y 0 = (.38-j.34) Y eq /Y 0 = (1.0+j1.2) Y s /Y 0 = (0-j1.2) l/ = =.228 Matching
Shunt admittance Y s /Y 0 = (0-j1.2) Short Circuit Impedance Short Circuit Admittance.11