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Example: Design a helical antenna operating at f = 475 MHz given pitch angle of 12.5° and turn radius of 10 cm such that the HPBW=39°. Solution: 1st find C and compare with ? to select either normal or axial mode. 2nd find # of turns, axial ratio, directivity. Cupped ground plane AXIAL-MODE HELIX Circularly polarized D ? 15 L/? C = ? D S ? Lo L ? ?/100 ? 3/4 ? Beam 50-? coaxial feed ? l = 3/8 ? ? ?/4 ? ?/? 2-to-1 (71%) bandwidth An Axial Mode Helix Invented by Kraus

          Example: Design a helical antenna operating at f = 475 MHz given pitch angle of 12.5° and turn radius of 10 cm such that the HPBW=39°.
Solution: 1st find C and compare with ? to select either normal or axial mode. 2nd find # of turns, axial ratio, directivity.

Cupped ground plane
AXIAL-MODE HELIX
Circularly polarized
D ? 15 L/?
C = ? D
S
?
Lo
L
? ?/100
? 3/4 ?
Beam
50-? coaxial feed
? l = 3/8 ?
? ?/4
? ?/?
2-to-1 (71%) bandwidth
An Axial Mode Helix Invented by Kraus

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Example: Design a helical antenna operating at f = 475 MHz given pitch angle of 12.5° and turn radius of 10 cm such that the HPBW=39°.
Solution: 1st find C and compare with ? to select either normal or axial mode. 2nd find # of turns, axial ratio, directivity.

Cupped ground plane
AXIAL-MODE HELIX
Circularly polarized
D ? 15 L/?
C = ? D
S
?
Lo
L
? ?/100
? 3/4 ?
Beam
50-? coaxial feed
? l = 3/8 ?
? ?/4
? ?/?
2-to-1 (71%) bandwidth
An Axial Mode Helix Invented by Kraus

Added by Josefina F.

University Physics with Modern Physics

Hugh D. Young 14th Edition

Instant Answer

Solved by Expert Adi S

08/20/2023

Step 1

5 degrees and a turn radius of 10 cm, aiming for a half-power beamwidth (HPBW) of 39° involves several steps. Let's break it down: ### Show more…

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Design a helical antenna operating at f = 475 MHz given pitch angle of 12.5° and turn radius of 10 cm such that the HPBW=39°. Solution: 1st find C and compare with λ to select either normal or axial mode. 2nd find # of turns, axial ratio, directivity.

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