Using EMQuest™ Viewer
for Antenna Pattern Files
Supplemental Guide
Table of Contents
Introduction ................................................................................................................................................4
Step 1:
Download EMQuest Viewer and Pattern Files .......................................................................4
Step 2:
Open a Pattern File ................................................................................................................8
Step 3:
Find the 3 dB or Half-power Beamwidth...............................................................................10
Step 4:
Find Front-to-back Ratio and Sidelobe Level .......................................................................15
ETS-Lindgren L.P. reserves the right to make changes to any product described herein in order to improve function, design, or for
any other reason. Nothing contained herein shall constitute ETS-Lindgren L.P. assuming any liability whatsoever arising out of the
application or use of any product or circuit described herein. ETS-Lindgren L.P. does not convey any license under its patent rights
or the rights of others.
© Copyright 2008 by ETS-Lindgren L.P. All Rights Reserved. No part of this document may be copied by any means
without written permission from ETS-Lindgren L.P.
Trademarks used in this document: The ETS-Lindgren logo and EMQuest are trademarks of ETS-Lindgren L.P.
Revision Record | MANUAL,USING EMQUEST VIEWER | Part #399292, Rev. A
Revision
Description
Date
A
Initial Release
June, 2008
Internet Address
http://www.ets-lindgren.com
USA
1301 Arrow Point Drive
Cedar Park, TX 78613 USA
Tel: +1.512.531.6400
Fax: +1.512.531.6500
Email: [email protected]
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Eura, Finland
Tel: +358.2.838.330
Fax: +358.2.865.1233
Email: [email protected]
Japan
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Bunkyo-ku, Tokyo 112-0006 Japan
Tel: +81.3.3813.7100
Fax: +81.3.3813.8068
Email: [email protected]
China
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China
Tel: +86.010.827.30877
Fax: +86.010.827.55307
Email: [email protected]
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iii
Introduction
This document describes how to use EMQuest™ Viewer to identify the beamwidths and the front-to-back ratio from the
pattern information of ETS-Lindgren antennas. Steps to obtain the typical parameters that can be obtained from the
normalized radiation pattern are provided.
Customers interested in using the antenna as a feed to a reflector can use the same procedure to obtain a
3 dB, half-power, or 10 dB beamwidth.
Radiation pattern information is available for most ETS-Lindgren antennas. The antennas have been measured at the
ETS-Lindgren A2LA-certified Calibration Lab. Two anechoic chambers for antenna measurement are located at the
ETS-Lindgren facility in Cedar Park, Texas:
•
Tapered anechoic chamber—For measurements 400 MHz to 6 GHz
•
Rectangular anechoic chamber—For measurements 700 MHz to 18 GHz
Step 1: Download EMQuest Viewer and Pattern Files
4
1.
Go to www.ets-lindgren.com.
2.
On the Products menu, click Software.
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Using EMQuest™ Viewer for Antenna Pattern Files
3.
On the Software page, click EMQuest™ Viewer.
4.
On the EMQuest™ Viewer page, click Download EMQuest™ Viewer.
The EMQuest™ Viewer page provides the minimum system requirements and recommended system
requirements to run EMQuest Viewer.
Using EMQuest™ Viewer for Antenna Pattern Files
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5
5.
Follow the steps to download and save the ZIP to the desired location on your computer.
Click the ZIP to extract the EMQuest Viewer executable.
Click the executable to install EMQuest Viewer.
6.
On the EMQuest™ Viewer page, click View Antenna Patterns to Download.
Some of the antenna pattern files are full 3D patterns and some are principal plane cuts of the pattern. Later
steps in this guide include instructions to extract the parameters for 3D patterns and 2D principal planes.
6
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Using EMQuest™ Viewer for Antenna Pattern Files
7.
Move the pointer over an antenna model to display a picture of the antenna.
8.
Click the antenna model name to download the pattern file.
9.
Follow the steps to download and save the pattern file to the desired location on your computer.
Go to page 8 to open the pattern file with EMQuest Viewer. You will use EMQuest Viewer to display the pattern and
search for parameters.
Using EMQuest™ Viewer for Antenna Pattern Files
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7
Step 2: Open a Pattern File
8
1.
Click the EMQuest™ Viewer icon to open EMQuest Viewer.
2.
On the File menu, click Open.
3.
Navigate to the antenna pattern file you saved in step 9 in the previous section.
4.
Select the pattern file you want to open and click Open.
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Using EMQuest™ Viewer for Antenna Pattern Files
5.
Large pattern files may display a warning indicating the file may take additional time. Click Yes.
This warning typically appears for 3D patterns with many frequency points.
The pattern file displays in the window.
Go to page 10 to find the 3 dB or half-power beamwidth.
Using EMQuest™ Viewer for Antenna Pattern Files
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9
Step 3: Find the 3 dB or Half-power Beamwidth
The half-power beamwidth quantifies the width of the main beam of the antenna. It is the angular separation of the points
of the main beam of the power pattern where the power equals one-half of the maximum value. Several EMC standards
call for the beamwidth and require that the entire Equipment Under Test (EUT) fall within the beamwidth of the antenna. If
the EUT does not fall within the beamwidth, then the antenna must be repositioned so that the entire EUT is covered
during emissions testing.
The 3 dB beamwidth can be found by looking at the pattern in polar format rather than 3D format. Following are the steps
to view a pattern in polar format.
1.
With the pattern displaying in the EMQuest Viewer, click the Polar Plot button to display the pattern in polar
format.
2.
To remove all of the lines except for the ones corresponding to the principal planes, right-click on the pattern.
The Graph Settings window will display.
10
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Using EMQuest™ Viewer for Antenna Pattern Files
3.
Click the Traces tab, and then click Hide All.
The check boxes will clear, and all the traces will be hidden.
4.
In the list of traces click to select the traces you want to display. For the principal planes, click the traces
corresponding to 0°, 90°, 180°, and 270°.
To change the line weight and color of a trace, click the trace and then select the desired characteristic in Line
Type and Trace Width.
Click OK.
Using EMQuest™ Viewer for Antenna Pattern Files
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11
5.
To change the scale for the 3 dB points on the main beam, right-click on the pattern for the Graph Settings
window.
6.
Click the Scale tab and type 3 in the Y Step box.
For example, a 3 dB Y-axis setting displays the 3 dB or half-power beamwidth.
To use your ETS-Lindgren antenna to illuminate reflectors, you will want the find the 10 dB beamwidth.
Type 10 in the Y Step box.
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Using EMQuest™ Viewer for Antenna Pattern Files
7.
Click Ok to display the plot.
In this example, the traces cross the 3 dB line at about 30° and 35° for each plane. The beamwidth is 60° on
one plane and about 70° on the other.
8.
To select a different frequency, right-click on the plot to display the Graph Settings window, click the
Dimension Depth tab, and then move the slider to the desired frequency.
Click OK.
Using EMQuest™ Viewer for Antenna Pattern Files
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13
The 3 dB beamwidth is shown in both principal planes. In this example, on one plane the beamwidth is
about 60° (± 35°) and on the other it is about 70° (±35°).
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Using EMQuest™ Viewer for Antenna Pattern Files
Step 4: Find Front-to-back Ratio and Sidelobe Level
1.
Using the steps in the previous sections, open the antenna pattern file and obtain the polar plot in the two
principal planes.
2.
Right-click on the plot to display the Graph Settings window.
3.
Click the Scale tab and type the Y-axis setting in the Y Step box. For an example, see step 6 on page 12.
4.
Click the Dimension Depth tab, and then move the slider to the desired frequency.
Click OK.
5.
Click the Cursor Readout button, and then move your cursor over the graph.
6.
Move the cursor to the largest sidelobe. The cursor readout will display the level and angle of the sidelobe. The
level of the largest sidelobe is the sidelobe level for that given plane and frequency.
In this example, the sidelobe level is -13.7 dB.
Using EMQuest™ Viewer for Antenna Pattern Files
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15
7.
Move the cursor to point to the pattern on the opposite direction of the main beam. The value read on the cursor
readout is the front-to-back ratio at that particular frequency.
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Using EMQuest™ Viewer for Antenna Pattern Files