US3858220A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Tunable spiral dipole antenna
Assignee: TITUS CHRISTOPHER A
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Filing: 1973-11-12
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Granted: 1974-12-31
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Expires: 1993-11-12
Abstract
Abstract A tunable dipole antenna including dipole arms formed of a pair of helical coils whose diameter is small compared to the wave length of the frequency to which the dipole antenna is tuned and whose length can be adjustably extended. The coil includes a plurality of turns of flat spring wire. When the coils are extended to a desired length, the turns of flat spring wire can be adjusted such that a number of the turns are expanded while the rest of the turns are contracted near the outer edge. The number of expanded turns can be varied at the given length of the coil to obtain tuning to the desired frequency.
Inventors
- 👤 S Arnow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 10:35
CPC Classifications
H; H01; H01Q; H01Q9/00; H01Q9/04; H01Q9/16; H01Q9/28; H01Q1/00; H01Q1/36; H01Q1/362; H01Q3/00; H01Q3/01
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
160 words
A dipole antenna capable of being adjustably tuned for a given frequency comprising, dipole arms formed of a pair of helical coils whose diameter is small compared to the wave length of the frequency being tuned and whose length can be adjustably expanded, common feed point means electrically connected to said coils for supplying current to the dipole arms, and supporting means for supporting the antenna such that said coils extend outwardly from said common feed point means, said coils being composed of flat spring wire formed into helical turns, each coil being adjustable to expand the pitch between the turns of one section of the coil to form a section of expanded turns and to contract the pitch between the turns of another section of the coil to form a section of contracted turns the number of turns in the expanded sections providing proper tuning of the antenna at the given frequency for the adjusted length of the coils.
Claim 2
Dependent Claim
160 words
A dipole antenna capable of being adjustably tuned for a given frequency comprising, dipole arms formed of a pair of helical coils whose diameter is small compared to the wave length of the frequency being tuned and whose length can be adjustably expanded, common feed point means electrically connected to said coils for supplying current to the dipole arms, and supporting means for supporting the antenna such that said coils extend outwardly from said common feed point means, said coils being composed of flat spring wire formed into helical turns, each coil being adjustable to expand the pitch between the turns of one section of the coil to form a section of expanded turns and to contract the pitch between the turns of another section of the coil to form a section of contracted turns the number of turns in the expanded sections providing proper tuning of the antenna at the given frequency for the adjusted length of the coils.
Claim 3
Dependent Claim
29 words
A dipole antenna as in claim 1 and wherein the helical turns in the expanded section are self-adjusting such that they have substantially equal pitch within the expanded section.
Claim 4
Dependent Claim
29 words
A dipole antenna as in claim 2 and wherein the flat spring wire has the flat surface in a plane transverse to the longitudinal axis of the helical coil.
Claim 5
Dependent Claim
26 words
A dipole antenna as in claim 2 and wherein said common feed point means includes balun means providing a balanced feeding current to the dipole arms.
Claim 6
Dependent Claim
22 words
A dipole antenna as in claim 4 and wherein said balun means includes a coil of several turns of coaxial feed line.
Claim 7
Dependent Claim
42 words
A dipole antenna as in claim 2 and wherein said supporting means comprises insulating card means having openings through which at least one turn of each of said coils can be wound, said supporting means also supporting said common feed point means.
Claim 8
Dependent Claim
29 words
A dipole antenna as in claim 2 and wherein said supporting means includes non-conductive wire means extending through said coils and adapted to be attached to a supporting member.
Claim 9
Dependent Claim
33 words
A dipole antenna as in claim 2 and wherein the center of the antenna is in a higher plane than the outer ends thereof such that said coils extend both outwardly and downwardly.
Claim 10
Dependent Claim
17 words
A tunable dipole as in claim 1 and wherein said coils have a diameter of 4 inches.
Claim 11
Independent Claim
142 words
A method for adjustably tuning a dipole antenna having a pair of helical coils as the dipole arms whose diameter is small compared to the wavelength and being composed of flat spring wire formed into helical turns, each coil being adjustable to expand the pitch between the turns of one section of the coil to form a section of expanded turns and to contract the pitch between the turns of another section of the coil to form a section of contracted turns, comprising the steps of: a. extending the overall length of the coils to a desired amount; b. measuring the voltage standing wave ratio (VSWR) at the feedpoint of the dipole arms, and c. varying the number of turns in the expanded section of each coil such that the voltage standing wave ratio (VSWR) is minimized across the desired frequency band.
Claim 12
Independent Claim
142 words
A method for adjustably tuning a dipole antenna having a pair of helical coils as the dipole arms whose diameter is small compared to the wavelength and being composed of flat spring wire formed into helical turns, each coil being adjustable to expand the pitch between the turns of one section of the coil to form a section of expanded turns and to contract the pitch between the turns of another section of the coil to form a section of contracted turns, comprising the steps of: a. extending the overall length of the coils to a desired amount; b. measuring the voltage standing wave ratio (VSWR) at the feedpoint of the dipole arms, and c. varying the number of turns in the expanded section of each coil such that the voltage standing wave ratio (VSWR) is minimized across the desired frequency band.
Claim 13
Dependent Claim
36 words
A method as in claim 10 and wherein said step of extending the overall length extends the length of the coils to a maximum amount available at a given location but not permanently deforming the coil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-30 | 1978-07-01 | 1978-12-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-30 | 1982-07-01 | 1982-12-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-30 | 1986-07-01 | 1986-12-31 | $7700.00 | Window Closed / Lapsed |