C ECOS University Department of Electrical Engineering

Waves Propagation and Antennas

LAB # 3

Dipole Antennas

& Parametric Analysis

Lab Instructor: Amjad Iqbal

Dipole Antennas

Note: Lab-2 is the pre-requisite of this Lab.

OBJECTIVE

This Lab is intended to show you how to Create, Simulate, and Analyze a Monopole and Dipole Antennas shown in Fig (1), using the Ansoft HFSS.

Fig (1): Dipole Antenna.

Dipole Antenna:

A Dipole antenna is a radio antenna that can be made of a simple wire, with a center-fed driven element. It consists of two metal conductors of rod or wire, oriented parallel and collinear with each other (in line with each other), with a small space between them. The radio frequency voltage is applied to the antenna at the center, between the two conductors as shown in Fig: (1).

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Lab-3. Dipole Antennas & Parametric Analysis

Design at f = 800MHz

1. Create Geometry of Dipole Antenna

Set Units Select the units mm.

Set Material Select the material as Copper.

Draw a Cylinder with

Name: Pole1

Radius: 6mm Height: 75 mm

Draw a Cylinder with

Name: Pole2 Space between Cylinders should be 12 mm.

Radius: 6mm Height: -75 mm

To fit the view: • Select the menu item View > Fit All > Active View

2. Create Lumped Port Excitation

To set the Grid Plane: Select the menu item Modeler > Grid Plane > YZ

Draw a rectangle with Name: Lumped Port Fig (2): Lumped Port Excitation

Design Rectangle with available space of 12 mm between the two cylinders having

length of 12 mm and width of 6mm.

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3. Create Air

To set the default material: Using the 3D Modeler Materials toolbar, choose vacuum.

Draw a box with

Name: Air Box position Opposite Corner

X: -100 dX: 200 Y: -100 dY: 200 Z: -200 dZ: 400

Fig (3): Air

4. Create Radiation Boundary a) To create a face list.

Select the menu item Edit > Select > By Name.

Select Object Dialog,o Select the objects named: Air o Click the OK button.

Select the menu item HFSS > Boundaries > Assign > Radiation.

Radiation Boundary window

o Name: Rad1 o Click the OK button

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Lab-3. Dipole Antennas & Parametric Analysis

5. Create a Radiation Setup a) To define the radiation setup

Select the menu item HFSS > Radiation > Insert Far Field Setup > InfiniteSphere

Far Field Radiation Sphere Setup dialog.o Phi:

Start: 0 Stop: 360

Step Size: 2 o Theta:

Start: -180 Stop: 180 Step Size: 2

Click the OK button.

Analysis Setup

1. Creating an Analysis Setup a) To create an analysis setup:

Select the menu item HFSS > Analysis Setup > Add Solution Setup.

Solution Setup Window:

Solution Frequency: 800 MHz

Maximum Number of Passes: 20

Maximum Delta S per Pass: 0.002

Click the OK button.

2. Adding a Frequency Sweep a) To add a frequency sweep:

Select the menu item HFSS > Analysis Setup > Add Sweep.o Select Solution Setup: Setup1 o Click the OK button.

Edit Sweep Window:o Sweep Type: Fast. o Frequency Setup Type: Linear Count.

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Lab-3. Dipole Antennas & Parametric Analysis

Start: 600 MHz Stop: 1000 MHz

Count: 100

Save Fields: Checked. o Click the OK button.

Analyze

1. Model Validation a) To validate the model:

Select the menu item HFSS > Validation Check. Click the Close button.

Note: To view any errors or warning messages, use the Message Manager.

2. Analyze a) To start the solution process:

Select the menu item HFSS > Analyze.

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Lab-3. Dipole Antennas & Parametric Analysis

REPORTS

1. Create Modal S-Parameter Plot - Magnitude

Create report (Modal S-Parameter Plot - Magnitude) of the Model.

Fig (4): S-Parameter Plot

2. Create Far Field Radiation Pattern

Create report (Far Field Radiation Pattern & 3-D Polar Plot) of the Model.

Ansoft Corporation Radiation Pattern 2 HFSSDesign1

0

-30 30

-4.00

-18.00

-60 60

-32.00

-46.00

-90 90

-120 120

-150 150

-180

Curve Info dB(GainTotal)

Setup1 : LastAdaptive

Phi='0deg' dB(GainTotal)

Setup1 : LastAdaptive

Phi='90deg'

Fig (5): 2-D Radiation Pattern of Dipole Antenna.

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Lab-3. Dipole Antennas & Parametric Analysis

Fig (6): 3-D Polar Plot Dipole Antenna.

In-Lab Task:

Design a Dipole Antenna for f = 1800MHz and create Reports of the Model, also find out:

Lower & Higher Frequencies Bandwidth of Antenna Max. Gain of Antenna Return loss at f=1800MHz

Comparison of Radiation Patterns for f=800MHz & f=1800 MHz

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Lab-3. Dipole Antennas & Parametric Analysis