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IMPEDANCE MATCHING AND

TUNING

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Outline2

1. Matching with Lump Elements2. Single-stub Tuning

3. The Quarter Wave Transformer 

4. Tapered Line

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Matching with Lumped Elements3

 L- section: The simplest type of matching network with two possible

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Analytic Solutions (1)4

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Analytic Solutions (2)5

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6

Smith Chart SolutionsDesign an L- section matching

network to match a series RC load

with an impedance

 Z L = 200 – 

 j 100 Ohm to a 100 Ohmline at frequency of 500 MHz

Solution

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7

Smith Chart Solutions

Solution

+j 0.7

 Z =1-j

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Solutions8

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Outline9

1. Matching with Lump Elements2. Single-stub Tuning

3. The Quarter Wave Transformer 

4. Tapered Line

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Single-stub Matching10

Uses a single open-circuited or short-circuited length of transmission l

connected either in parallel or in series with the transmission feed line

distance from the load

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Shunt stub11

Match load impedance Z L = 60 –  j 80 Ohm to a 50 Ohm line

at frequency of 2 GHz using a single

shunt open-circuit stub

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Shunt stub12

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Shunt stub13

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Series stub14

Match load impedance Z L = 100 –  j 80 Ohm to a 50 Ohm

line at frequency of 2 GHz using a

single series open-circuit stub

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Series stub15

 Normalized load impedance:

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Series stub

16

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The Quarter-Wave Transformer18

Bandwidth for TEM lines

Characteristic of thel 

/4 transformer 

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Exponential Tapper20

At z = 0, Z (0) = Z 0 z = L, then

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Triangle Tapper21

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Homework22

Onsite 5.1a, 5.2a, 5.3, 5.5

Homework 5.1b, 5.2b, 5.4, 5.6, 5.13, 5.23

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Double Stub Matching23

Design a double stub shunt tuner to match

a load impedance Z L = 60 –  j 80 Ohm to a 50 Ohm line at

frequency of 2 GHz. The stubs are open-

circuited stubs and are space l /8.

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24

 Normalized load impedance:

 Z L = 0.3 – 

 j 0.4

Double Stub Matching