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David Conn VE3KL. Polarization in Nature, Technology and Radio. 1932 Chevy ?. Credits. http://www.polarization.com/land/land.html. http://www.windows.ucar.edu/tour/link=/earth/images/earth_magneto_image.html&edu=high. Acknowledgements. Wild Rose Chapter 151 QCWA

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David conn ve3kl

David Conn VE3KL

Polarization in Nature, Technology and Radio

1932 Chevy ?

Credits

http://www.polarization.com/land/land.html

http://www.windows.ucar.edu/tour/link=/earth/images/earth_magneto_image.html&edu=high

David Conn VE3KL QCWA Sept 2006


Acknowledgements
Acknowledgements

Wild Rose Chapter 151 QCWA

QCWA Chapter 70 Members

Ken Oelke VE6AFO

Graham Ide VE3BYT

Clare Fowler VE3NPC

Ken Pulfer VE3PU

Doug Leach VE3XK

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

What is Polarization ?

David Conn VE3KL QCWA Sept 2006


Light and radio waves
Light and Radio Waves

  • Composed of Electric Fields, E

  • E at right angles to direction of propagation

  • E can be Horizontal, Vertical, Circular..

  • Unpolarized…….. The Sun

David Conn VE3KL QCWA Sept 2006


Why is polarization important
Why is Polarization Important ?

  • The Ionosphere and materials change the polarization of Radio Waves

  • Operation of Lasers, LCD displays, Sun Glasses

  • Medical research…. Diabetes

  • Biology .. Insects..

David Conn VE3KL QCWA Sept 2006


The basics 1 reflection refraction
The Basics … #1[Reflection..Refraction]

Standing Wave Region

SWR

Air

Reflected Wave

Water

Refracted Wave

Incoming Plane Wave

David Conn VE3KL QCWA Sept 2006


The brewster angle e in plane of the screen
The Brewster Angle[E in plane of the Screen]

53 Degrees

NO Reflection

Like a matched Load

SWR = 1:1

Air

Water

Refracted Wave

Incoming Plane Wave of Light

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Basics.. #2The Wire Grid

Polarizer

Horizontal Wires

Incoming Unpolarized Light/Radio Wave

Vertically Polarized

Horizontally Polarized

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

The Wire Grid

Reflector or Transmitter

Horizontal Wires

Vertically Polarized Wave

Circularly Polarized Wave

Horizontally Polarized

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Examples

  • Rainbows

  • Sun Glasses

  • Liquid Crystal Displays

  • The Magnetosphere

  • Four Antennas

  • Insects

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Rainbows

Are they Polarized ?

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

YES…But Why?

Horizontal

At Top

Note the Double Rainbow

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Here is Why

Unpolarized Light from the Sun

Water Droplet

Brewster Angle

42 degrees

Vertical

Polarized perpendicular to the Screen

Horizontal

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Polarized Sunglasses

Transmit Vertically Polarized Light

Vertical lost due to Brewster

Horizontal lost by Glasses

Wire Grid

Angle Important

Brewster Angle

Horizontally Polarized

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Liquid Crystals

cyanobiphenyl materials

1888

Liquid Crystal

Credits

http://www.kth.se/fakulteter/TFY/kmf/lcd/lcd~1.htm

http://nobelprize.org/educational_games/physics/liquid_crystals/history/

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

LCD Display

http://nobelprize.org/educational_games/physics/liquid_crystals/history/

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Polarization in the Ionosphere

Big Impact on Radio and EME

Earth’s Magnetic Field

Linear Polarization

(45 degrees tilt)

Elliptical Polarization

50 MHz

Electrons in the Ionosphere

70 Km

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Polarization in the Ionosphere

Faraday Rotation

Horizontal

Polarization

Input

Earth’s Magnetic Field

Vertical Polarization

Output

A Horizontal Dipole will NOT

Talk to a Horizontal Dipole.

Electrons in the Ionosphere

David Conn VE3KL QCWA Sept 2006


Some examples of circularly polarized antennas
Some Examples of Circularly PolarizedAntennas

  • Two Crossed Dipoles …… Basic

  • Two Crossed Dipoles …… Very simple

  • The Classic Helix …. Complex

  • The Skew Planar …. Very Complex

David Conn VE3KL QCWA Sept 2006


Two crossed dipoles
Two Crossed Dipoles

Horizontal Antenna

LHC

λ/4

50 Watts

Transmitter

100 Watts

Direction of Propagation

50 Watts

Vertical Antenna

Antennas Fed In-Phase

(Details not shown)

David Conn VE3KL QCWA Sept 2006


A simple circularly polarized antenna
A Simple Circularly Polarized Antenna

Two crossed dipoles

Connected in parallel

One LONGER than the other

Radiates into the Screen

Zin = 50 Ohms

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

The HelixAntenna

  • Invented by John Kraus

  • Used by Amateurs for Satellite Communications

  • Difficult to Analyze

  • Relatively High Gain …. 15 dBc

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

The Helix Antenna

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

The Skew Planar Antenna

900 MHz Beacon Applications

  • A Story of its Own

  • Researched extensively by Graham Ide (VE3BYT)

  • Omni Directional and Circularly Polarized

  • First reported in QST 1960’s

  • Not used again until Graham got interested

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

The Skew Planar Antenna

70 Cm Beacon Applications

VE3BYT

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Insects

Some Insects have complex polarized eyes

http://xray.optics.rochester.edu/workgroups/cml/opt307/spr04/greg/

David Conn VE3KL QCWA Sept 2006


Polarization in nature technology and radio

Summary

  • The Concepts and Use of Polarized Signals Span many disciplines

  • Two Ideas Presented:

    The Brewster Angle

    The Wire Grid

David Conn VE3KL QCWA Sept 2006


Vy 73 david
VY 73 David

David Conn VE3KL QCWA Sept 2006


Where to get more information and credits
Where to Get More Informationand Credits

  • http://webphysics.davidson.edu/physlet_resources/dav_optics/Examples/polarization.html

  • http://en.wikipedia.org/wiki/Liquid_crystal_display

  • http://www.ngsir.netfirms.com/englishhtm/Lissajous.htm

  • Fields and Waves in Communication Electronics: Ramo, Whinnery, Van Duzer ; John Wiley, third edition, 1994, ISBN 0-0471-58551-3

David Conn VE3KL QCWA Sept 2006