EMPIRE XCcel Tutorial

Patch antenna started from scratch

2 Vorlage Apr-10 ©

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Overview

Topics

•

Layer creation•

Property setting

•

Object creation•

Port definition

•

Simulation parameters•

Field recording

•

Simulation•

Results

•

Target frequency: 2.45 GHz

•

Substrate: Rogers, 635um, epsr=2.2

•

Patch size ~ 40mm x 40mm (lambda/2)

•

Substrate size ~ 80mm x 80mm

•

Infinite ground plane

Start:•

Start Empire XCcel•

Press „Start From Scratch“•

Select „File –

Save As“•

Select, e.g. C:\tutorial0\scratch (create folder), save file

3 Vorlage Apr-10

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Step 1

Layer creation

•

Open

the layer

list on

the left•

Open

the default layer•

Optionally,

recolor,

rename layer•

Set

height

to z=0...635

Layers are used • to group objects with common properties• to define the height of objects, like boxes and polygons• to set the insertion point of library objects, like ports• to lock or hide objects• to define their properties

Comments: In this example (cylindrical) objects are created in the

xy-plane. The perpendicular coordinates are taken from the layer’s height.The values entered here represent the thickness of a substrate. The default unit is micron (can be changed in the Simulation Setup)

4 Vorlage Apr-10

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Step 2

Property setting

•

Press Change

Property•

Select

Dielectric •

Enter Rel. Permittivity: 2.2•

Press OK to leave

the

property

editor

Properties can be divided into • physical, basic, like conductors or dielectric materials• functional, like circuit elements, e.g. resistor• functional, like field recording settings, animations• functional, like mesh hints• Advanced, for special applications

Comments: The default property is conductor (PEC). Here, we want to define the substrate and therefore the property is changed here. The material properties can also be set by selecting materials from the Database. Layers may have multiple properties, if they are not contradictious.

5 Vorlage Apr-10

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Step 3

Object creation

•

Close layer

list•

Open Structure

list•

Open Create

–

Box•

Enter xy coordinates

of Point 0: x=-40000, y=-40000•

Enter xy coordinates

of Point 1: x=40000, y=40000•

Press Close•

Press „Zoom to extends“

or

press the

Z-key

Cylindrical objects can be created in several ways• Structure list, editing coordinates• Structure list, pressing the arrows and using the cursor in the

drawing area• Pressing button “Create Box/Cylinder/Poly”

and using the method above• Drawing an arrow and pressing “Create Box/Cylinder”

afterwards• Entering a set of points and pressing “Create Poly”

afterwards

Comments: The object is created immediately after pressing on Create –

Box with the default values. The drawing is updated as soon as values are modified.

6 Vorlage Apr-10

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Step 4

More objects

•

Open layer

list, Press Create layer•

Repeat Step

1, using height

z=635...645, adjust layer settings

•

Repeat Step

2, here: keep conductor as property•

Repeat Step

3, Points

P0(-20000,-20000), P1(20000,20000)

•

(For more complex structures repeat Step

4 until geometry is complete)

Object modifications can be created in several ways:• Select object, press button move, assign, stretch, rotate, mirror, …

and enter operator (arrow, point, number,…) • Select object, activate handle, move to handle

•

Drag middle mouse to copy object•

Drag right mouse button to move object•

Drag left mouse button to stretch handle• Select two or more objects und apply a Boolean operation merge,

intersect, subtract, drill, e.g. to cut out a hole

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Step 5

Port definition

•

Open

layer

list, Press

Create layer•

Repeat Step

1, rename, recolor the layer, using height

z=0...635, keep property•

Close layer

list•

Open Port Library•

Open

Create

–

Perpendicular

Port•

Enter xy coordinates

of Point 0: x=-9000, y=-1000•

Enter xy coordinates

of Point 1: x=-7000, y=1000•

Press

Close

Ports:• Perpendicular lumped ports connect top and bottom conductors, height should be distance between patch and ground• Lumped ports connect either between left and right or up and down conductors, height should be equal to metal thickness• Signal line of feed line ports are inserted at the minimum height, all other parameters are adjusted in the Parameters Menu• Port numbers should be unique unless simultaneous excitation is

desired• Port impedances are 50 Ohm by default• The start point of absorbing ports have to placed at one of the

outermost grid line• Lumped ports and concentrated ports may not be placed at the boundaries

8 Vorlage Apr-10

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Step 6

Simulation setup

•

Close layer

list and Port Library list, Open Simulation Setup

•

Enter

Start frequency: 1.25e9•

Enter

End frequency: 2.5e9•

Open Boundary

Conditions•

Set zmin

to „electric“

and zmax

„open

6“

Simulation setup:•

Geometry: 1 unit in the drawing equals 1 micron, here•

Excitation Response: Information about the structure for automatic meshing and end criteria

•

Frequency: Determines the range of the DFT, the pulse width used

is derived by cell size

•

Accuracy: resolution, energy

decay

level, PGA•

Loss Calculation: Model used for loss calculation, default is lossless•

Boundary conditions: •

electric defines infinite ground plane, Et=0, (magnetic Ht=0)•

Open N emulates open space (N should be larger in the main radiation direction)

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Step 7

Far Field recording

•

Open layer

list, Press Create

layer, name

„n2f“•

Change property

to Field

–

Storage

-

Nearfield

to Farfield •

Add

Point: 2.45e9•

Exit

with

OK•

Close layer

list

Far fields:• Far fields are obtained in post processing by a transformation of the nearfield• The near field is recorded on a box which is created automatically, depending on the frequency settings• Further adjustments can be set after simulation in Simulation Tab -

Post processing –

Farfield

window:•

Normalization (Gain, Directivity, maximum, …)•

Sweep mode (2D cuts, 3D pattern,…

)•

Rotation•

Far field components (linear, circular, …)•

Mirror planes

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Step 8

Simulation

•

Press „Create Discretization“•

Press „Zoom to extends“•

Press „Start Simulation“

Meshing and simulation:•

The created mesh lines are displayed on the bars at the right and at the bottom•

The automatic meshing automatically enlarges the simulation domain to account for the far field transformation

•

The simulation domain is marked by the dashed lines which indicate open boundary condition•

In the front view, the simulation border at the bottom is indicated by a dark red solid line which represents electric (green: magnetic) boundary conditions

•

With “Start Simulation”

the structure is checked, meshed and prepared for simulation•

As soon as the voltage plot comes up the simulation starts, the evolution of the time signal is shown

•

When the end criteria has been reached, the post processing is triggered and the S-

parameters are displayed.

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Step 9

Results

Results:•

The different results can be viewed by selecting one of the Tabs

(Voltage, S-Parameters, Impedance,

Farfield, Additional)•

The style of the plots can be changed in the sub-tab Setup (e.g. angular plot for

farfield, select Type e()

farfield

polar)•

Result files are automatically detected in the right list using a naming convention. Additional files can be selected from other folder by using the “import”

button in the Setup•

Result files selected for display are displayed

in

the left

list

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Step 10

Near fields

Remarks:•

A 2nd

simulation is needed for recording the field at the desired frequency if it is not known in advance•

By default, the volume defined by layer height and perpendicular

plane is used for recording•

The volume of field recording can also be defined by an arbitrary box on this layer•

The style of the animation can be changed in the animation property definition

•

Return to Draft

Tab, Create

layer

„Anim“

, z=635...645•

Change property

to Field

–

Storage

-

Distribution•

Add

Point: 2.45e9, Exit

with

OK•

Add

property

Field

–

Display -

Animation•

Exit

with

OK•

Repeat

simulation•

3D view

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Step 11

Near fieldsDefaults, electric field Defaults

+ Field plot amplitude: 50000(Properties –

Animation -

General)

Defaults + Amplitude: 50000+ Equiline

Color: black+ Equiline

Style: equi_20(Properties –

Animation -

Additional)

Defaults + Amplitude: 50000+ Equiline

Color: black+ Equiline

Style: equi_20+ Arrow

field

plot

:On(Properties –

Animation -

Additional)