Electromagnetic Field
Animations
Introduction
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Exploring Electromagnetic Fields in and
around antennas |
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Animate the fields to help visualize |
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Small feed antennas – simpler fields |
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Complement to explanations in Appendix
6C |
Antenna - Electromagnetic
Fields
Field Relationship
Example:
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Open Rectangular Waveguide |
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Simple, well known |
Calculate field inside
waveguide
Calculate full aperture
field
WR-90
WR-90 E&H
WR-90 open
WR-90 rim
Near Field ß Fourier à Far Field
E x H
Coffee can
Coffee rim
Interference from
multiple sources
Feed with two sources
Penny
Reduce sidelobes from
edge currents
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Choke rings |
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VE4MA |
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Chaparral |
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Dual-mode feeds |
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W2IMU |
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Clavin ’74 |
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Diagonal Feeds |
VE4MA
VE4MA rim
Chaparral stock
Chaparral flush
W2IMU
W2IMU dual-mode feed
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very small edge current
G3PHO
Bad IMU
Clavin
74
Diagonal Horns
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No Flare – 0.73 wavelengths sq. |
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1.4 wavelengths square |
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14 degree flare |
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30 degree flare |
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60 degree flare |
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1.85 wavelengths square |
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30 degree flare |
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60 degree flare |
No flare
1.4, 14
1.4, 30
1.4, 60
Diagonal rim
1.85, 30
1.85, 60
Flared horns
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Conical |
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1.88 wavelength diameter |
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Rectangular |
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Small, for DSS dish |
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Surplus, only E-plane flare |
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Conical
Conical rim
DSS
AT-68/U
Reverse feeds
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G4ALN Penny feed |
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RSGB “Professional” Penny |
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DC3QS Bent penny |
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DK2RV Small disk 30 mm |
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DK2RV Large disk 60 mm |
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DK2RV Large disk with rim |
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RSGB waveguide dipole |
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Clavin 1954 feed |
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Penny
Pro
DC3QS
30 mm
diffraction
60 mm
Rim
Phase error
Waveguide dipole
Clavin ‘54
Other feeds
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Primestar |
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Vertical polarization |
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Horizontal polarization |
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Sectoral horn |
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E-plane corrugations |
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H-plane corrugations |
Primestar vertical
Primestar horizontal
E-plane
H-plane
corrugations
Multiband feeds
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W5ZN 10 and 24 GHz |
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W5ZN with choke |
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Some multiband experiments |
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2 and 5 GHz (like W5ZN) |
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3 and 10 GHz (dual-mode style) |
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W5ZN at 10
W5ZN at 24
W5ZN choke 10
W5ZN choke 24
2 and 5 experiment
3 and 10 experiment at
3456
3 and 10 experiment at 10
GHz
SUMMARY
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Near Field Animations |
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Visualize antenna operation |
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Highlight strange behavior |
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Help explain performance |
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Slide 68
Slide 69
W1GHZ favorite feeds
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Prime focus dish |
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VE4MA |
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Chaparral |
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W2IMU |
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Offset dish |
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Rectangular horn |
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large W2IMU |
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