VSWR and Γ on Smith Charts - EMPossible

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Electromagnetics: Microwave Engineering VSWR and Γ on Smith Charts

Transcript of VSWR and Γ on Smith Charts - EMPossible

Page 1: VSWR and Γ on Smith Charts - EMPossible

Electromagnetics:

Microwave Engineering

VSWR and Γon Smith Charts

Page 2: VSWR and Γ on Smith Charts - EMPossible

Lecture Outline

•Determining the voltage standing wave ratio (VSWR)

•Determining the reflection coefficient Γ

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Page 3: VSWR and Γ on Smith Charts - EMPossible

The Horizontal Bar on Smith Charts

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VSWR

2Reflectance

Reflection Coefficient

Page 4: VSWR and Γ on Smith Charts - EMPossible

Determining the Voltage Standing Wave Ratio (VSWR)

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Determining VSWR

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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

Page 6: VSWR and Γ on Smith Charts - EMPossible

Example #2 –What is the VSWR?

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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.

Page 7: VSWR and Γ on Smith Charts - EMPossible

Example #2 –What is the reflection coefficient Γ?

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0.62

VSWR 4.3