A simple presentation on smith chart

1. Microwave Engineering(16EC-601)

2. Outline of Lecture of Smith Chart
What is Smith Chart
Application of Smith Chart
Transmission line theory
Identify key Reference point
Example
 impedence Matchine type

3. INTRODUCTION
• Smith chart was invented by Phillip Smith in 1939 as a graph-based method
of simplifying the complex math used to describe the characteristics of
RF/microwave components, and solve a variety of RF problems.
• Smith Chart consist of a plot of the normalized impeadance or admittance,
with the angle and magnitude of a generalized complex reflex coefficient in a
unity circle.
• This is also applicable for lossless as well as lossy line. when the impedance has
a fixed reactance but a
varying value
of resistance.
These circles appear
when the impedance’s
resistance is kept
constant and the X value
is varied.

4. Application of Smith Chart
• In any domain of RF engineering, the smith chart has various
applications
• Used in the transmission line to calculate any impedance value
at any load.
• Admittance value at any load.
• Used for the purposes of impedance matching
• Employed to know the value of VSWR amongst others.

5. Transmission Line
Ratio of the
reflected wave to
the incident wave
Ratio of the load impedance to
the charactertics impedance

6. Smith chart summarized

8. Impedance matching
Maximum power delivered
Improved SNR
Reduce amplitude and phase errors in power distribution networks
Consider factors such as complexity, frequencies of operation, ease of
implementation, and behavior with variable loads.

9. Type of impedance matching
1.Single Stub matchine
2.Double Stub matchine
A simple form of variable impedance matching device is the
single stub tuner. It consists of a transmission line with a stub of
short or open circuit that can be used as the reactive element
in the impedance matching method.
A double stub tuner provides variable distance from the load,
and is widely used in laboratory practice as a single frequency
matching device. In actual design practice, it is replaced by
more compact and broadband approaches

10. .
.
Example 1

11. Example 2

12. Single stub mtching

14. REFERANCE
• Microwave Devices and Circuits (samuel Liao)- By
EasyEngineering.net
• Youtube.com
• Google.com