Post on 29-Nov-2021
transcript
Electromagnetics:
Microwave Engineering
VSWR and Γon Smith Charts
Lecture Outline
•Determining the voltage standing wave ratio (VSWR)
•Determining the reflection coefficient Γ
2
The Horizontal Bar on Smith Charts
3
VSWR
2Reflectance
Reflection Coefficient
Determining the Voltage Standing Wave Ratio (VSWR)
4
Determining VSWR
5
1. Plot the normalized load impedance on the Smith chart.
2. Draw a circle centered on the Smith chart that intersects this point.
3. The VSWR is read where the circle crosses the real axis on the right side.
Example #1: 50 W line connected to 75+j10 W load impedance.
0
75 101.5 0.2
50
LZ jz j
Z
+= = = +
impedance
VSWR = 1.55
1
VSWR
Example #2 –What is the VSWR?
6
in
inin
0
0.4 0.
20 40
20 40
0 8
5
Z j
Z jz
Zj
= − W
− W= = −=
W
VSWR 4.3
A 50 W line is connected to 20-j40 W load impedance.
Example #2 –What is the reflection coefficient Γ?
7
0.62
VSWR 4.3