Power Divider

Microwave EngineeringMicrowave EngineeringCHO, Yong HeuiCHO, Yong Heui

Microwave Microwave EngineeringEngineering

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2

Basic properties

1. Power divider

Division of power: scattering matrix Lossless system

- - Scattering matrix: unitary matrix

3-port networks 5-port networks

222

22

2

lossy

11

1

10

S

** VVVVTT

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T-junction power divider

Simple 3-port network Waveguide or microstrip line Lossless or all-port matched network

port at 021in YYYjBY

1. Power divider

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2:1 ratio power divider

Find the output characteristic impedances so that the input power is divided in a 2:1 ratio when a source impedance is 50 [Ohms]

02

01

2

3

3

ZZ

ZZ

3

13

2

0

33

22

11

S

S

S

1. Power divider

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Port impedance:

Series resistance:

All port matched network

Lossy network

T-junction resistive power divider

0Z

03

1ZR

011

101

110

2

1lossyS

1. Power divider

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Wilkinson power divider

All port matched network Lossy network Isolation port: 2 and 3 Even-odd mode analysis: superposition

001

001

110

2lossy

jS

1. Power divider

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Broadband divider

Simulation

Fabrication

Multisection Wilkinson power divider

1. Power divider

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Directional coupler

4 port network Input①, through②, coupled③, and isolated④ port Waveguide or microstrip line Even-odd mode analysis

2. Coupler

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Voltage ratio

2. Coupler

Quarter-wave length line Symmetric line Quadrature hybrid

factor coupling a is where,0

1

1

4

1

3

2

1

2

CV

V

CV

V

CjV

V

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Broadband directional coupler

Multisection directional coupler

2. Coupler

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Crosstalk

2. Coupler

Chip level

PCB level

Cm

Lm

Active line

Victim Line

Zo

Zo

Zo

Zo

Zo, tpd

Zo, tpd

tr

1 2

3 4

Signal switching Forward crosstalk Backward crosstalk

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Lange coupler

Tight coupling Edge-coupled lines Fabrication: narrow width and wire bonding MMIC (Monolithic Microwave Integrated Circuit)

VGA (Variable Gain Amplifier)

2. Coupler

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Quadrature (branch line) hybrid

90° hybrid 3dB coupler Symmetric port Even-odd mode analysis

3. Hybrid

010

001

100

010

2

1

j

j

j

j

S

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Ring (rat race) hybrid

180° hybrid 3dB coupler Asymmetric port Even-odd mode analysis

0110

1001

1001

0110

2

jS

3. Hybrid

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