Antennas -- in 50 Minutes or Less!

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Antennas -- in 50 Minutes or Less!

• Cynthia Furse
• Department of Electrical and Computer Engineering
• Utah State University
• furse_at_ece.usu.edu

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Introduction to Antennas

• Antenna Parameters
• Types of Antennas
• Where to find out more

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Antenna Parameters

• Radiation Pattern
• Directivity
• Gain
• Planes ( E or H, Elevation or Azimuth)
• Lobes (HPBW, FSLBW, etc.)
• Input Impedance
• Link Budget

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Common Types of Antennas

• Wire Antennas
• Dipoles, Monopoles, Monopoles above Gnd
• Patch, Printed circuit board antennas
• Slots, apertures
• Dishes, Reflector Antennas
• Arrays

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Dipole Antenna
Fromhttp//www.qth.com/antenna/dipole.gif,plot.gi
f
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Folded Dipole
Fromhttp//www.qth.com/antenna/fdipole.gif
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Monopole Antenna
From http//www.letstalk.com//Images/mits-ah-129.
GIF
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Monopole Antenna
Fromhttp//www.letstalk.com//Images/5-a.gif
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The University of Utah mm-resolution Head Model
Furse, Lazzi, Gandhi, FDTD Computation of Power
Deposition in the Head for Cellular Telephones,
Proc. 1996 IEEE APS Symposium
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Applications Cellular Telephones
SAR Distribution in Adult - 835 MHz - Simplified
Phone Model - l /4 antenna
Pandit,McDermott,Lazzi,Furse,Gandhi, Electrical
Energy Absorption in the Human Head, presented
at IEEE Visualization 96, S.F., CA 1996
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SAR Distributions - 835 MHz (adult, 10 year old,
5 year old)
10 year old
Adult
5 year old
From Gandhi, Lazzi, Furse, IEEE Trans. MTT
44(10) 1996
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Monopole Antenna above Ground Dipole Antenna
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V-Antenna
v.gif
Fromhttp//www.qth.com/antenna/v.gif
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Loop Antenna
Fromhttp//www.downeastmicrowave.com/graphics/kbl
oop.gif
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Pagers
From http//www.letstalk.com//Images/13-a.gif
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Discone Antenna
From http//www.northcountryradio.com/discfig.htm
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Reflector (Dish) Antenna
From http//www.dssdirectv.com/chanmas1.jpg
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Arecibo Observatory -- Puerto Rico
From http//www.naic.edu/about/photos/aoviews/tes
cop.jpg
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Arecibo Observatory
Fromhttp//www.naic.edu/about/photos/aoviews/wide
ao.jpg
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Arecibo Observatory
From http//www.naic.edu/about/photos/aoviews/tes
cop4.jpg
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Horn Antennas
From http//www.tmo.hp.com/tmo/datasheets/Images/
img-HP11966J-1lg.gif
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Conical Horn Antenna
From http//www.afcsat.com/CH14_MOT2.jpg
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GPS Antennas
Fromhttp//www.lowe.co.uk/gpsant.jpg
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GPS Antenna
SEN 67157549 SENSOR SYSTEMS L1
Fromhttp//gracie.grdl.noaa.gov/GRD/GPS/Projects/
ANTCAL/Models/Images/SENS67157549.s.jpg
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GPS Antenna with Choke Ring
SEN 67157549cr SENSOR
SYSTEMS L1 WITH CHOKE RING
Fromhttp//gracie.grdl.noaa.gov/GRD/GPS/Projects/
ANTCAL/Models/Images/SENS671575cr.s.jpg
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GPS Antenna
LEI AT302
Fromhttp//gracie.grdl.noaa.gov/GRD/GPS/Projects/
ANTCAL/Models/LEI_AT302.shtml
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Antenna Arrays
Two Elements -- Pattern adds constructively or
destructively
From http//server5550.itd.nrl.navy.mil/projects/
HAARP/images/ant/pat1.gif
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Antenna Arrays
More Elements Higher Directivity Sidelobes
From http//server5550.itd.nrl.navy.mil/projects/
HAARP/images/ant/pat2.gif
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Scanning Antenna Array
Changing the phases on the element feeds can make
a scanning array.
Fromhttp//server5550.itd.nrl.navy.mil/projects/H
AARP/images/ant/pat3.gif
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Arrays
Fromhttp//www.qth.com/antenna/tiny2rl.gif
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Yagi-Uda Arrays
From http//cust.iamerica.net/dwhowell/yagimax.jp
g
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Satellite Antenna Array
Fromhttp//www.qth.com/antenna/hfsatrl.gif
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HAARP Observatory
HAARP (High frequency Active Auroral Research
Program) is to be a major Arctic facility for
upper atmospheric and solar-terrestrial research.
HAARP is being built on a DoD-owned site near
Gakona, Alaska.
Fromhttp//server5550.itd.nrl.navy.mil/projects/H
AARP/images/ohd.jpg
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HAARP Antenna Array
The HF antenna system to be used for Active
Ionospheric Research at the HAARP site will
assist other facility instruments in the study
the overhead ionosphere. As a result, it too has
been designed to optimize or restrict the
transmission pattern to lie within a narrow
overhead region. To achieve this desirable
antenna pattern, the HAARP system uses an "array"
of individual antenna elements. The HAARP antenna
array is similar or identical to many other types
of directive antenna types in use for both
military and civilian applications including air
traffic control radar systems, long range
surveillance systems, steerable communication
systems and navigation systems.
Fromhttp//server5550.itd.nrl.navy.mil/projects/H
AARP/images/twr/pan2.jpg
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HAARP -- Feed Sytem
Fromhttp//server5550.itd.nrl.navy.mil/projects/
HAARP/images/ant/tpile.jpg
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HAARP -- Matching Networks
From http//server5550.itd.nrl.navy.mil/projects/
HAARP/images/ant/amu.jpg
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Corner Reflector Antenna
From http//www.northcountryradio.com/crfigs.htm
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Anything Radiates Fan-tenna
Fromhttp//www.qth.com/antenna/fanfull.gif
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The Bottom Line

• ANYTHING radiates. Sometimes you want it to, and
  sometimes you dont.
• To choose an antenna for your design, prepare a
  LINK BUDGET to determine the necessary gain and
  directivity of your antenna.
• Dont forget MATCHING NETWORKS to prevent
  reflection between your antenna and your circuit.

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Antenna References on the Web
General http//www.ee.surrey.ac.uk/Personal/D.Jef
feries/antennas.html GPS Antennas Lowe
Industries http//www.lowe.co.uk/antrev2.htmlhttp
//www.lowe.co.uk/antrev2.html Antenna
Calibration http//gracie.grdl.noaa.gov/GRD/GPS/P
rojects/ANTCAL/index.shtml Ham North Country
Radio http//www.northcountryradio.com/techtips.h
tm Antenna Elmer http//www.qth.com/antenna/anten
na.htm HAARP Observatory http//server5550.itd.n
rl.navy.mil/projects/HAARP/ant3.html Arecibo
Obervatory http//www.naic.edu/aboutao.htm