The document discusses impedance matching in microwave engineering. It covers: 1. The conditions required for maximum power transfer between a transmission line and load, which is when their impedances are equal. 2. Various matching network topologies that can be used including L-networks, T-networks, and pi-networks using lumped elements, as well as single-stub, double-stub, and quarter-wave transformer matching networks. 3. Design procedures and examples for L-network, single-stub shunt tuning, and double-stub matching networks using the Smith Chart. Transitions with broader bandwidth than quarter-wave transformers like binomial and Chebyshev multisection lines are also covered.

1. Impedance
Matching
Microwave Engineering
CHO, Yong Heui

2. Microwave Engineering
1. Impedance matching
Maximum power transfer
출처 : KAIST
  Condition
- Z 0 = ( Z L )*
 Matching network
 Reflection
 No reflection
- Z0 = Z L
Phase shifter
2 EM Wave Lab

3. Microwave Engineering
1. Impedance matching
Matching with lumped elements
  Compact size
 Difficulties in finding the proper value of L or C
 L-network, T-network, and Π-network
3 EM Wave Lab

4. Microwave Engineering
1. Impedance matching
Procedure: L-network
  Define zL = Z L / Z0
 Draw yL = 1 / zL
 Find jB to intersect the
circle z L = 1 + jx
 Draw zL
 Find jX to cancel out jx zin = 1 + jx + jX = 1
4 EM Wave Lab

5. Microwave Engineering
1. Impedance matching
Example
  Design the L section matching network to
match the transmission line,
where
Z L = 200 − j100[ Ω], Z 0 = 100[ Ω], f = 500 MHz
Smith chart
5 EM Wave Lab

6. Microwave Engineering
1. Impedance matching
Single-stub matching
  Open stub and short stub
Short stub (L)
Open stub (C)
6 EM Wave Lab

7. Microwave Engineering
1. Impedance matching
Single-stub matching
  Simple matching network
Smith chart
7 EM Wave Lab

8. Microwave Engineering
1. Impedance matching
Procedure: shunt stub
  Define zL = Z L / Z0
 Draw yL = 1 / zL
 Move to the direction of
generator
 Find the intersection of the
circle y L = 1 + jb yin = y L + y S
 Adjust the length of a shunt = 1 + jb − jb = 1
stub y S = − jb
8 EM Wave Lab

9. Microwave Engineering
1. Impedance matching
Example
  Design the single-stub shunt tuning network to
match the transmission line,
where
Z L = 15 + j10[ Ω], Z 0 = 50[ Ω], f = 2GHz
Smith chart
9 EM Wave Lab

10. Microwave Engineering
1. Impedance matching
Double-stub matching
  Fixed length between the load and stub
Smith chart
10 EM Wave Lab

11. Microwave Engineering
1. Impedance matching
Quarter-wave transformer
  Easy calculation of the matching network
 Narrow bandwidth characteristics
Z1 = Z 0 Z L , l = λ / π
11 EM Wave Lab

12. Microwave Engineering
1. Impedance matching
Transitions
  Complicated design procedure
 Broad bandwidth characteristics
 The theory of small reflections
  Binomial multisection line
 Chebyshev multisection line
 Tapered line
12 EM Wave Lab