Quadrifilar helix antenna tuning using pin diodes
First Claim
Patent Images
1. An antenna system comprising:
- a resonant quadrifilar helix antenna having a plurality of arms with said arms grounded at a first predetermined location on each of said plurality of arms;
bias means for providing an electrical signal to said resonant antenna; and
short circuit means connected to said resonant antenna at a second predetermined location on each of said plurality of arms, said short circuit means for receiving said electrical signal and for providing a short circuit to ground at said second predetermined location on each of said plurality of arms.
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Abstract
An antenna is tuned in separate discrete frequency bands by changing the ctrical length of the antenna. PIN diodes are placed at predetermined locations on the antenna coaxial cable radiating elements. When it is desired to shorten the antenna for a higher frequency band use, the diodes are biased short circuiting segments of the antenna. When the lower frequency band use is desired, diodes are unbiased so that the diodes act like a very small capacitance shunted by a large resistance which is essentially an open circuit permitting the entire length of the antenna to operate.
89 Citations
12 Claims
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1. An antenna system comprising:
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a resonant quadrifilar helix antenna having a plurality of arms with said arms grounded at a first predetermined location on each of said plurality of arms; bias means for providing an electrical signal to said resonant antenna; and short circuit means connected to said resonant antenna at a second predetermined location on each of said plurality of arms, said short circuit means for receiving said electrical signal and for providing a short circuit to ground at said second predetermined location on each of said plurality of arms. - View Dependent Claims (2, 3, 4)
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5. An antenna system comprising:
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a resonant quadrifilar helix antenna having a plurality of arms with said arms grounded at a first predetermined location on each of said plurality of arms; bias means for providing one of positive, negative and null DC electrical signal to said resonant antenna; first short circuit means connected to said resonant antenna at a second predetermined location on each of said plurality of arms, said first short circuit means for receiving said electrical signal and for providing a short circuit to ground at said second predetermined location on each of said plurality of arms; and second short circuit means connected to said resonant antenna at a third predetermined location on each of said plurality of arms, said second short circuit means for receiving said electrical signal and for providing a short circuit to ground at said third predetermined location on each of said plurality of arms. - View Dependent Claims (6, 7, 8)
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9. An antenna system comprising:
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a resonant quadrifilar helix antenna having a plurality of arms with said arms grounded at a first predetermined location on each of said plurality of arms; bias means for providing one of a first positive, negative and null DC electrical signal and for providing one of a second positive, negative and null DC electrical signal to said resonant antenna; first short circuit means connected to said resonant antenna at a second predetermined location on each of said plurality of arms, said first short circuit means for receiving one of said first and one of said second electrical signals and for providing a short circuit to ground at said second predetermined location on each of said plurality of arms upon receipt of said first and second electrical signals; second short circuit means connected to said resonant antenna at a third predetermined location on each of said plurality of arms, said second short circuit means for receiving one of said first and one of said second electrical signals and for providing a short circuit to ground at said third predetermined location on each of said plurality of arms upon receipt of said first and second electrical signals; third short circuit means connected to said resonant antenna at a fourth predetermined location on each of said plurality of arms, said third short circuit means for receiving one of said first and one of said second electrical signals and for providing a short circuit to ground at said fourth predetermined location on each of said plurality of arms upon receipt of said first and second electrical signals; and fourth short circuit means connected to said resonant antenna at a fifth predetermined location on each of said plurality of arms, said fourth short circuit means for receiving one of said first and one of said second electrical signals and for providing a short circuit to ground at said fifth predetermined location on each of said plurality of arms upon receipt of said first and second electrical signals. - View Dependent Claims (10, 11, 12)
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Specification