directional coupler using mwo

Directional Coupler Circuit Design & Analysis using Microwave Office

By: Manjunatha Reddy.H.VManjunatha_hv@rediffmail.com

Directional Coupler

Directional Coupler

Directional Coupler

Example 1:

Design a 20dB coupled line coupler in microstrip, characteristic impedance of 50 Ohm,and a center frequency of 9GHz. Plot the coupling anddirectivity from 5 to 13GHz.

1. Create New Schematic Shown Below

2. Go to Elements Tab

3. Select MicrostripsLinesCoupled LinesJunctions

Complete Directional Coupler Schematic

MSUBEr=2.6H=0.504 mmT=0.018 mmRho=1Tand=0.002ErNom=2.6Name=SUB1

MLINID=TL1W=1.37 mmL=5 mm

W

W

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4

MCLINID=TL3W=1.344 mmS=0.664 mmL=5.68 mm

MLINID=TL4W=1.37 mmL=5 mm

MSTEP$ID=TL5

MSTEP$ID=TL2 MSTEP$

ID=TL6

MLINID=TL7W=1.37 mmL=5 mm

MSTEP$ID=TL8

MLINID=TL9W=1.37 mmL=5 mm

MBENDID=TL10W=1.37 mmANG=90 DegM=0.6

MBENDID=TL11W=1.37 mmANG=90 DegM=0.6

PORTP=1Z=50 Ohm

PORTP=2Z=50 Ohm

PORTP=3Z=50 Ohm

PORTP=4Z=50 Ohm

Add MSUB Substrate bloc

View the complete Layout of Directional Coupler Layout

Add Graph

Right click & select add MeasurementThen Choose S11, then Apply, S21 etc

Directional Coupler Simulation ResponseSimulate the design for 5 to 13 GHz in steps of 0.1

5 7 9 11 13Frequency (GHz)

Graph 1

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-10

0DB(|S(1,1)|)Directional Coupler

DB(|S(1,1)|)Directional Coupler EM Extract

DB(|S(1,1)|)EM_Extract_Doc

DB(|S(2,1)|)Directional Coupler

DB(|S(2,1)|)Directional Coupler EM Extract

DB(|S(2,1)|)EM_Extract_Doc

DB(|S(3,1)|)Directional Coupler

DB(|S(3,1)|)Directional Coupler EM Extract

DB(|S(3,1)|)EM_Extract_Doc

DB(|S(4,1)|)Directional Coupler

DB(|S(4,1)|)Directional Coupler EM Extract

DB(|S(4,1)|)EM_Extract_Doc

Then Simulate The Directional Coupler using EMSightFor Final EM Simulation

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Directional Coupler

Example 2:

Design a 20dB coupled line coupler in microstrip, characteristic impedance of 50 Ohm,and a center frequency of 3GHz. Plot the coupling and directivity from 1 to 5GHz.

Directional Coupler Schematic

MSUBEr=2.6H=0.504 mmT=0.018 mmRho=1Tand=0.002ErNom=2.6Name=SUB1

W

W

1

2

3

4

MCLINID=TL3W=1.341 mmS=0.651 mmL=17.12 mm

PORTP=1Z=50 Ohm

PORTP=2Z=50 Ohm

PORTP=3Z=50 Ohm

PORTP=4Z=50 Ohm

Directional Coupler Layout

Directional Coupler EM Structure

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Directional Coupler Simulation Response

1 2 3 4 5Frequency (GHz)

Graph 1

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-20

03 GHz-20.97 dB

DB(|S(1,1)|)Directional Coupler

DB(|S(1,1)|)Directional Coupler EM Extract

DB(|S(1,1)|)EM_Extract_Doc

DB(|S(2,1)|)Directional Coupler

DB(|S(2,1)|)Directional Coupler EM Extract

DB(|S(2,1)|)EM_Extract_Doc

DB(|S(3,1)|)Directional Coupler

DB(|S(3,1)|)Directional Coupler EM Extract

DB(|S(3,1)|)EM_Extract_Doc

DB(|S(4,1)|)Directional Coupler

DB(|S(4,1)|)Directional Coupler EM Extract

DB(|S(4,1)|)EM_Extract_Doc

Directional Coupler Hands on Example

Example 3:

Design a 10dB coupled line coupler in microstrip, characteristic impedance of 50 Ohm,and a center frequency of 12GHz. Plot the coupling and directivity from 10 to 14GHz.