MWO – Application of EM Structure in Filter Design Soh Ping Jack Sabarina Ismail.

MWO – Application of EM Structure in Filter Design

Soh Ping JackSabarina Ismail

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DISTRIBUTED FILTER DESIGN PROCESS

Filter Specification

Low-pass Prototype

Design

Scaling & Conversion

Filter Implementation

Optimization & Tuning

Done using MWO

Board Specification

Additional Step in EM Structure

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parameters2. Know how to operate in EM Structure3. Know how to define board parameters4. Know how to use TxLine Calculator5. Know how to draw structures & ports6. Know how to add results graphs7. Optimize & tune filter to get best response

To do this you have to be familiar with MWO’s EM

Structure

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parameters2. Know how to operate in EM StructureKnow how to operate in EM Structure3. Know how to define board parametersKnow how to define board parameters4. Know how to use TxLine CalculatorKnow how to use TxLine Calculator5. Know how to draw structures & portsKnow how to draw structures & ports6. Know how to add results graphsKnow how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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1.0 KNOW THE BOARD PARAMETERS

TODAY’S TASK To design a low pass filter on a RT/Duroid

6002 board with the following parameters:

a. tanδ = 0.0012b. εr = 2.94c. Metallization Layer Thickness (t) = 35 umd. Substrate Height (h) = 1.6 mme. Desired Freq Range (f) = 1 GHz

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1.0 KNOW THE BOARD PARAMETERS

Photo Board Cross Sectiona. tanδ = 0.0012b. εr = 2.94c. Metallization Layer Thickness (t) = 35 umd. Substrate Height (h) = 1.6 mm

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1.0 KNOW THE BOARD PARAMETERS

Photo Board Cross Section

Photo Resist LayerCopper Foil LayerRT/Duroid 6002 Dielectric Layer

Photo Protective Film

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parametersKnow the board’s parameters2. Know how to operate in EM Structure3. Know how to define board parametersKnow how to define board parameters4. Know how to use TxLine CalculatorKnow how to use TxLine Calculator5. Know how to draw structures & portsKnow how to draw structures & ports6. Know how to add results graphsKnow how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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2.0 OPERATING IN EM STRUCTURE

2.1 Working in the EM Structure Environment

To add a new EM Structure, right-click on “EM Structure”

icon and select “New EM Structure”

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2.0 OPERATING IN EM STRUCTURE

2.1 Working in the EM Structure EnvironmentA pop-up window will appear after clicking “New EM

Structure”, click on “Create” button

Click on “Create”

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2.0 OPERATING IN EM STRUCTURE

2.2 Setting Project Options (Freq Sweep)

To edit simulation freq sweep, double-click on the

“Project Options” icon

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2.0 OPERATING IN EM STRUCTURE

2.3 Setting Project Options (Freq Sweep)

To edit simulation freq sweep, double-click on the

“Project Options” icon

Define desired “Start Freq”, “Stop Freq” & “Freq Step”. It should not be too refined in

an initial simulation

List of the simulated freq points will be listed down when “Apply” button is

clicked

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parametersKnow the board’s parameters2. Know how to operate in EM StructureKnow how to operate in EM Structure3. Know how to define board parameters4. Know how to use TxLine CalculatorKnow how to use TxLine Calculator5. Know how to draw structures & portsKnow how to draw structures & ports6. Know how to add results graphsKnow how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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3.0 DEFINING BOARD PARAMETERS

3.1 Defining an Enclosure

To modify an enclosure’s property, double-click on the “Enclosure” box to

trigger a pop-up window

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3.0 DEFINING BOARD PARAMETERS

3.2 Defining an Enclosure – Enclosure Tab

X and Y-dimensions & Divisions will determine Cell Size (resolution of a mesh in

the structure)

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3.0 DEFINING BOARD PARAMETERS

3.3 Defining an Enclosure – Dielectric Layers

Define RT/Duroid 6002 properties on Layer 2

Define air properties on Layer 1 (Air thickness = 10 x

substrate thickness)

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3.0 DEFINING BOARD PARAMETERS

3.4 Defining an Enclosure - Boundaries

Layer above Layer 1 is defined as “Approximately

Open”

Layer below Layer 2 is defined as “Perfect

Conductor”

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parametersKnow the board’s parameters2. Know how to operate in EM StructureKnow how to operate in EM Structure3. Know how to define board parametersKnow how to define board parameters4. Know how to use TxLine Calculator5. Know how to draw structures & portsKnow how to draw structures & ports6. Know how to add results graphsKnow how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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4.0 TXLINE CALCULATOR

4.1 Triggering the TXLine Calculator

To open up the TXLine Calculator, go to “Tools” and click

on “TXLine”

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4.0 TXLINE CALCULATOR

4.2 TXLine Calculator Main Interface

Enter all parameters required for

impedance, freq, electrical length, &

substrate information

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1 2

4.0 TXLINE CALCULATOR

4.3 Using TXLine Calculator to know W & L

50Ω

30.75Ω 30.75Ω

50Ω129.8Ω 129.8Ω

45.59Ω

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4.0 TXLINE CALCULATOR

4.4 W & L for 50Ω Line

For a 50Ω Line;1. L = 24.2763 mm2. W = 4.03134 mm

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4.0 TXLINE CALCULATOR

4.5 Drawing W & L

1

L = 24.2763 mm

W = 4.03134 mm

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parametersKnow the board’s parameters2. Know how to operate in EM StructureKnow how to operate in EM Structure3. Know how to define board parametersKnow how to define board parameters4. Know how to use TxLine CalculatorKnow how to use TxLine Calculator5. Know how to draw structures & ports6. Know how to add results graphsKnow how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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5.0 DRAWING STRUCTURES & PORTS

5.1 Drawing Rectangular Structures

To add a rectangular shaped patch, click on the “Draw Rectangular Conductor”

icon at the top toolbar

Drag the mouse cursor to the desired X and Y dimensions

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5.0 DRAWING STRUCTURES & PORTS

5.2 Drawing Patch & Feedlines – Adding Port

To add an edge port on a specific section of a line, click on the “Draw” and select “Add edge port”

Important: Please ensure that the desired section of a line where the port is to be placed is clicked on first

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5.0 DRAWING STRUCTURES & PORTS

5.3 Drawing Patch & Feedlines – Placing Port

After selecting, place the port on the edge of the feed line. The port will be

active indicating a legal/valid placement of the port on a specific

edge on the feed line.

Note: The edge port will be labeled “1”, “2” and so on, to indicate the port number. In this case, a filter

has two ports

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5.0 DRAWING STRUCTURES & PORTS

5.4 Drawing Patch & Feedlines – Extending Port

After placement of the port, go to the edge of the port till a double-sided

arrow is seen. Then start dragging a port extension inwards. An arrow like

this should be seen

Note: Port extension should be at least 3 times the height of the substrate. In

this case, it is 3x1.6mm=4.8mm

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DISTRIBUTED FILTER DESIGN PROCESS

A. BOARD SPECIFICATION1. Know the board’s parametersKnow the board’s parameters2. Know how to operate in EM StructureKnow how to operate in EM Structure3. Know how to define board parametersKnow how to define board parameters4. Know how to use TxLine CalculatorKnow how to use TxLine Calculator5. Know how to draw structures & portsKnow how to draw structures & ports6. Know how to add results graphs7. Optimize & tune filter to get best responseOptimize & tune filter to get best response

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6.0 ADDING RESULTS GRAPHS

6.1 Adding Results Graphs & Charts

To add a result graph, right-click on the “Graph” icon on the left window and select “Add Graph”. A pop-up

window will appear

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6.0 ADDING RESULTS GRAPHS

6.2 Adding Results Graphs & Charts – Graph Types

A pop-up window like this will appear, select the appropriate type of

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6.0 ADDING RESULTS GRAPHS

6.3 Adding Results Graphs & Charts – Measurements

After inserting the appropriate graph type, it still does not know what type of parameters that is to be plotted on it.

To define this, right click on the “Graph’s Name” and click on “Add

Measurement”

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6.0 ADDING RESULTS GRAPHS

6.4 Adding Results Graphs & Charts – ParametersA pop-up window like this will appear,

select the correct EM Structure’s result to be plotted by selecting the correct

Data Source Name

Check on the correct parameter. In this case, it is S11. Ensure that the “dB”

checkbox is checked

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6.0 ADDING RESULTS GRAPHS

6.5 Starting a Simulation

To start simulation, click on the Analyze button on the tool bar at the

top

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6.0 ADDING RESULTS GRAPHS

6.6 Viewing Results

Since this is an 0.5 dB equal ripple LPF;1. Pass band starts from MIN to 1GHz2. Stop band starts from 1GHz to MAXA good filter will have:1. S11 response < –10dB value at pass band 2. S21 response > -3dB value at pass band3. S21 response < -10dB value at stop band

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1 2

7.0 D.I.Y No 1

Try to finish and simulate the 0.5dB Equal Ripple, N=3, 1GHz LPF

50Ω

30.75Ω 30.75Ω

50Ω129.8Ω 129.8Ω

45.59Ω

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7.0 D.I.Y No 1

0.5dB Equal Ripple, N=3, 1GHz LPF Sim Results

0.8 0.9 1 1.1 1.2Frequency (GHz)

Graph 1

-40

-30

-20

-10

0

1.0929 GHz-10.01 dB

1.0111 GHz-3.193 dB

0.94 GHz-34.48 dB

DB(|S(1,1)|)EM Structure 1

DB(|S(2,1)|)EM Structure 1

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1 2

7.1 D.I.Y No 2

Try to finish and simulate the Max Flat, N=3, 1GHz LPF

50Ω

25Ω 25Ω

50Ω100Ω 100Ω

25Ω

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0.6 0.8 1 1.2Frequency (GHz)

Graph 1

-30

-25

-20

-15

-10

-5

0

0.88337 GHz-3.229 dB

0.8 GHz-28.02 dB

0.96778 GHz-10.05 dB

DB(|S(2,1)|)EM Structure 1

DB(|S(1,1)|)EM Structure 1

7.1 D.I.Y No 2

Max Flat, N=3, 1GHz LPF Sim Results

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8.0 REFERENCES

• Pozar, D.M. (2005) Microwave Engineering 3rd Ed. John Wiley & Sons, N.J, USA

• Pozar, D.M. (2001) Microwave and RF Design for Wireless Systems, John Wiley & Sons, N.J, USA

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9.0 REVISION HISTORY

Version Date Comments Author

R01.00 12-09-2006 Initial Draft P.J Soh