US3176299A - Circular-type antenna with symmet-rically movable arms providing capacitive and inductive variation for tuning - Google Patents

Circular-type antenna with symmet-rically movable arms providing capacitive and inductive variation for tuning Download PDF

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Publication number
US3176299A
US3176299A US200580A US20058062A US3176299A US 3176299 A US3176299 A US 3176299A US 200580 A US200580 A US 200580A US 20058062 A US20058062 A US 20058062A US 3176299 A US3176299 A US 3176299A
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antenna
circular
tuning
symmet
rically
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US200580A
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John B Caraway
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Electronics Res Inc
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Electronics Res Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04—Resonant antennas
    • H01Q9/16—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole
    • H01Q9/26—Resonant antennas with feed intermediate between the extremities of the antenna, e.g. centre-fed dipole with folded element or elements, the folded parts being spaced apart a small fraction of operating wavelength
    • H01Q9/265—Open ring dipoles; Circular dipoles

Definitions

  • This invention relates to antennae for radio apparatus and more particularly antennae for use in high frequency transmissions systems.
  • One example of the type of antenna involved is shown in Patent No. 2,467,961, issued to John B. Caraway, Jr., and H. Kees on April 19, 1949.
  • High frequency antenna systems are well known in the art, however, these known systems exhibit certain disadvantages.
  • One of the disadvantages is that of frequency limitation imposed upon the antenna systems by the nature of their construction.
  • I provide a segmented circular type high frequency antenna in which the ends of the segments of the circle are mounted on a block in such a manner that the ends of the segments may be moved relative to each other, thereby varying the diameter of the circle. This variation causes the inductance of the antenna to be varied.
  • capacitor plates are connected to the opposite ends of the segments from the mounting block and the distance between these capacitor plates will be varied in the same direction as the diameter of the circle.
  • the capacitance of the antenna will be varied simultaneously with the inductance.
  • I connect to the feed line with a flexible strap a feed strap clamp on the circular antenna.
  • the clamp is provided with an adjustable coupling so that the clamp may be loosened and displaced relative to the segment of the circle, thereby changing the effective input impedance of the antenna.
  • FIG. 1 is a plan view of one illustrative embodiment of this invention
  • FIG. 2 is a view in elevation of the embodiment of FIG. 1;
  • FIG. 3 is a side view of FIG. 2.
  • loop block 11 having a loop mounting plate 12 secured there- 3,176,299 Patented Mar. 30, 1965 to by any convenient means such as by welding.
  • a pair of circular segments or semi-circular conductors 13 and 14 terminate at one end in rectangular blocks 15 which blocks are threaded to receive suitable bolts 16 which pass through the plate 12 to threadably engage the blocks 15.
  • the segment 13 includes a pair of spaced circular conductors While segment 14 includes a pair of spaced circular conductors with T section 17, shown in FIGS. 2 and 3, lying on its side with one end connected to block 15 and the other ends connected to the spaced circular conductors. It is understood that the spacing between the conductors of a pair is arbitrary while spacing between the pairs of conductors determines the inductance of the antenna.
  • elongated slots 18 are provided in the loop mounting plate 12, such that the bolts 16 may be loosened and the semi-circular loops or segments 13 and 14 displaced relative to each other and the bolts 16 subsequently tightened. Variation of this relative displacement varies the inductance of the antenna.
  • a pair of capacitor plates 19 are mounted in substantially parallel relationship. The capacitance of this capacitor will be varied as the plates are displaced relative to each other. Thus, the capacitance of the antenna will be varied at the same time that the inductance is varied.
  • the means used to adjust the antenna to change the diameter of the pairs of semicircular segments can be any number of structures such as lead screws, spacers, cams, slots in a backup plate as shown in the drawing or any means that would change the diameter and thereby increase or decrease the inductance of the loop antenna.
  • a feed-through insulator or bushing 21 is secured to the loop block by suitable means such as by bolt 22 and nuts 24, 26 and 28.
  • An 0 ring 29 is mounted between bushing 21 and block 11 to provide a moisture seal.
  • Bolt 22 is connected to a suitable conductor 30 which passes through the insulating bushing 32 in a direction substantially perpendicular to bolt 22.
  • a clamping member 34 is clamped to circular segments 14 by suitable means such as a pair of nut and bolt assemblies 37.
  • a flexible conducting strap 38 is connected to the bolt 22 between nuts 24 and 26 and is connected to clamp 34 to supply high frequency energy to the segment 14. Since these bolt assemblies 37 may be loosened and the clamp 34 moved relative to the segment 14, the point at which energy is supplied to the antenna and thus the input impedance is varied. It is understood, of course, that the loop mounting plate is grounded or connected to the other side of the feed line to which conductor 30 is connected to provide the necessary return path for the electrical energy.
  • bolts 16 are loosened and the segments 13 and 14 are moved relative to each other to change the distance between the segments which distance is indicated by the double-headed arrow 20.
  • the bolts 16 are again tightened.
  • This adjustment of the antenna varies the inductance by changing the distance indicated by the double arrow 20 and also changes the capacitance because it changes the distance between the capacitor plates 19 indicated by the double-headed arrow 42.
  • the bolt assemblies 37 are loosened and the feed strap clamp 34 is moved along the segment 14 to thus modify the input impedance of the antenna to compensate for changes in input impedance caused by the relative movement of the semi-circular conductors.
  • the antenna is preferably mounted in a horizontal plane as -viewed in FIGS; 2 and 3 of the drawing. 'It is'also understood that'the segments 13 and 14,-while shown to contain two substan! tially parallel conductors connected together at the ends; this antenna'mayinclude a greater number" of circular segments such as for example 6 or 8 substantially parallel semi-circular tubes connected at their ends.
  • this antenna isi'suitable I by Well known techniques'of conductive contact to constitute a circular conductor opened at a gap between said capacitor plates, cooperative for-both transmitting and receiving high frequency Waves 1" andlthat various physical sizes maybe employed to determine the overallband of frequency "to which the antenna may be'tuned. 4
  • a circular-type antenna comprising'a'pair of identical semi-circular conductors, a-capacitor plate permanently mounted in'afixed 'positionpon one end of .each conductor,
  • a mounting vbracket affixed near the other end of reach conductor, a mounting plate for supporting each of said brackets with said" conductors held symmetrically in adjustablemeans in said brackets and said mounting plate for moving bothzsaidtconductors apart the same amount to -vary the distancevb'etweenlsaid capacitor plates while maintaining the inductive 'gcomponent of the antenna identical inboth conductors; and a feed line constituting the 'sole conductive connection.

Description

Mamh 1955 J. B. CARAWAY CIRCULAR-TYPE ANTENNA WITH SYMMETRICALLY MOVABLE ARMS PROVIDING CAPACITIVE'AND INDUCTIVE VARIATION FOR TUNING Filed June 6, 1962 INVENT OR Jay/v5. (ZR/1W4) BY who, gmub .x mm
ATTORNEYS CIRCULAR-TYPE ANTENNA WITH SYMMET- RICALLY MOVABLE ARMS PROVIDING CA- PACITIVE AND INDUCTIVE VARIATION FOR TUNING John B. Caraway, Newburgh, Ind., assignor to Electronics Research, Inc., Evansville, Ind., a corporation of Indiana Filed June 6, 1962, Ser. No. 200,580 1 Claim. (Cl. 343--744) This invention relates to antennae for radio apparatus and more particularly antennae for use in high frequency transmissions systems. One example of the type of antenna involved is shown in Patent No. 2,467,961, issued to John B. Caraway, Jr., and H. Kees on April 19, 1949.
High frequency antenna systems are well known in the art, however, these known systems exhibit certain disadvantages. One of the disadvantages is that of frequency limitation imposed upon the antenna systems by the nature of their construction.
Accordingly, it is an object of this invention to provide an improved high frequency antenna system which obviates the above mentioned disadvantage.
It is another object of this invention to provide an improved circular type high frequency antenna which may be easily adjusted over a relatively broad range of frequencies.
It is still another object of this invention to provide an improved circular type antenna which can be tuned over a relatively wide range of frequencies by varying the inductance of the antenna.
It is still another object of this invention to provide a circular type antenna which can be tuned over a relatively wide range of frequencies by adjusting the inductance as well as the capacitance of the antenna.
It is still another object of this invention to provide an improved circular type antenna in which the inductance and input impedance can be varied.
Briefly, in accordance with aspects of one illustrative embodiment of this invention, I provide a segmented circular type high frequency antenna in which the ends of the segments of the circle are mounted on a block in such a manner that the ends of the segments may be moved relative to each other, thereby varying the diameter of the circle. This variation causes the inductance of the antenna to be varied.
In accordance with other aspects of this invention, capacitor plates are connected to the opposite ends of the segments from the mounting block and the distance between these capacitor plates will be varied in the same direction as the diameter of the circle. Thus, the capacitance of the antenna will be varied simultaneously with the inductance.
In accordance with still other aspects of this invention, I connect to the feed line with a flexible strap a feed strap clamp on the circular antenna. Advantageously, the clamp is provided with an adjustable coupling so that the clamp may be loosened and displaced relative to the segment of the circle, thereby changing the effective input impedance of the antenna.
United States Patent These and various other objects and features of the invention will'be more clearly understood by a reading of the detailed description in conjunction with the drawing in which:
FIG. 1 is a plan view of one illustrative embodiment of this invention;
FIG. 2 is a view in elevation of the embodiment of FIG. 1; and,
FIG. 3 is a side view of FIG. 2.
Referring now to the drawing, there is depicted a loop block 11 having a loop mounting plate 12 secured there- 3,176,299 Patented Mar. 30, 1965 to by any convenient means such as by welding. A pair of circular segments or semi-circular conductors 13 and 14 terminate at one end in rectangular blocks 15 which blocks are threaded to receive suitable bolts 16 which pass through the plate 12 to threadably engage the blocks 15. I
The segment 13 includes a pair of spaced circular conductors While segment 14 includes a pair of spaced circular conductors with T section 17, shown in FIGS. 2 and 3, lying on its side with one end connected to block 15 and the other ends connected to the spaced circular conductors. It is understood that the spacing between the conductors of a pair is arbitrary while spacing between the pairs of conductors determines the inductance of the antenna.
Advantageously, elongated slots 18 are provided in the loop mounting plate 12, such that the bolts 16 may be loosened and the semi-circular loops or segments 13 and 14 displaced relative to each other and the bolts 16 subsequently tightened. Variation of this relative displacement varies the inductance of the antenna. On the opposite ends of the antenna segments 13 and 14 from the mounting block 11, a pair of capacitor plates 19 are mounted in substantially parallel relationship. The capacitance of this capacitor will be varied as the plates are displaced relative to each other. Thus, the capacitance of the antenna will be varied at the same time that the inductance is varied. The means used to adjust the antenna to change the diameter of the pairs of semicircular segments can be any number of structures such as lead screws, spacers, cams, slots in a backup plate as shown in the drawing or any means that would change the diameter and thereby increase or decrease the inductance of the loop antenna.
A feed-through insulator or bushing 21 is secured to the loop block by suitable means such as by bolt 22 and nuts 24, 26 and 28. An 0 ring 29 is mounted between bushing 21 and block 11 to provide a moisture seal. Bolt 22 is connected to a suitable conductor 30 which passes through the insulating bushing 32 in a direction substantially perpendicular to bolt 22.
A clamping member 34 is clamped to circular segments 14 by suitable means such as a pair of nut and bolt assemblies 37. Advantageously, a flexible conducting strap 38 is connected to the bolt 22 between nuts 24 and 26 and is connected to clamp 34 to supply high frequency energy to the segment 14. Since these bolt assemblies 37 may be loosened and the clamp 34 moved relative to the segment 14, the point at which energy is supplied to the antenna and thus the input impedance is varied. It is understood, of course, that the loop mounting plate is grounded or connected to the other side of the feed line to which conductor 30 is connected to provide the necessary return path for the electrical energy.
When it is desired to vary the frequency at which the antenna is adjusted, bolts 16 are loosened and the segments 13 and 14 are moved relative to each other to change the distance between the segments which distance is indicated by the double-headed arrow 20. When the segments have been moved relative to each other, the bolts 16 are again tightened. This adjustment of the antenna varies the inductance by changing the distance indicated by the double arrow 20 and also changes the capacitance because it changes the distance between the capacitor plates 19 indicated by the double-headed arrow 42. After the antenna segments 13 and 14 are adjusted and tightened, the bolt assemblies 37 are loosened and the feed strap clamp 34 is moved along the segment 14 to thus modify the input impedance of the antenna to compensate for changes in input impedance caused by the relative movement of the semi-circular conductors.
r V g 4.
This may be accomplished trial and error to determine the point of maximum power transfer. After this point is located, the "bolt assemblies 37- aretightened and the antenna is ready for operation.
a It is understood, of course, that the antenna is preferably mounted in a horizontal plane as -viewed in FIGS; 2 and 3 of the drawing. 'It is'also understood that'the segments 13 and 14,-while shown to contain two substan! tially parallel conductors connected together at the ends; this antenna'mayinclude a greater number" of circular segments such as for example 6 or 8 substantially parallel semi-circular tubes connected at their ends.
It is further understood-that this antenna isi'suitable I by Well known techniques'of conductive contact to constitute a circular conductor opened at a gap between said capacitor plates, cooperative for-both transmitting and receiving high frequency Waves 1" andlthat various physical sizes maybe employed to determine the overallband of frequency "to which the antenna may be'tuned. 4
, While I have shownv and described one illustrative embodiment of this invention, it is understood that. the concepts thereof may be applied to other embodiments without-departingfrom the spirit and scope, of this in vention. 3
What is claimed is: v
A circular-type antenna comprising'a'pair of identical semi-circular conductors, a-capacitor plate permanently mounted in'afixed 'positionpon one end of .each conductor,
a mounting vbracket affixed near the other end of reach conductor, a mounting plate for supporting each of said brackets with said" conductors held symmetrically in adjustablemeans in said brackets and said mounting plate for moving bothzsaidtconductors apart the same amount to -vary the distancevb'etweenlsaid capacitor plates while maintaining the inductive 'gcomponent of the antenna identical inboth conductors; and a feed line constituting the 'sole conductive connection. to said semi-circular conductors coupled rat a position'of predeterminedffeed line impedance established on said? conductors;
7 References Cited by the Examiner 2 UNITED STATES "PATENTS 84 6,57 1 f S/SZjGermanyL 867,256 2/53 Germany. 707,573 54 Great: Britain. 7
SAAL ACHQ Primary Examiner.
US200580A 1962-06-06 1962-06-06 Circular-type antenna with symmet-rically movable arms providing capacitive and inductive variation for tuning Expired - Lifetime US3176299A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284801A (en) * 1964-01-15 1966-11-08 John J Bryant Large loop antenna
US3576567A (en) * 1967-07-11 1971-04-27 Edward H Shively Circularly polarized broadcast antenna
DE3220989A1 (en) * 1981-06-05 1982-12-30 Tokyo Shibaura Denki K.K., Kawasaki, Kanagawa AERIAL DEVICE WITH A BASE PLATE AND A FRAME-SHAPED ANTENNA ELEMENT
US5072233A (en) * 1990-07-20 1991-12-10 Zanzig Gary R Loop antenna with integral tuning capacitor
FR2699739A1 (en) * 1992-12-22 1994-06-24 France Telecom Omnidirectional and multipolarization antenna.

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE356248C (en) * 1922-07-18 Bruno Rosenbaum Dipl Ing Loop antenna for wireless character transmission
US1851178A (en) * 1923-06-18 1932-03-29 Lillian Louise Hammond Antenna
US2059299A (en) * 1933-06-01 1936-11-03 Rca Corp Short wave tuner
US2324462A (en) * 1941-11-15 1943-07-13 Gen Electric High frequency antenna system
US2447879A (en) * 1945-11-19 1948-08-24 Gen Electric Antenna
US2467961A (en) * 1946-02-20 1949-04-19 Electronies Res Inc Antenna
US2467962A (en) * 1947-01-28 1949-04-19 Electronies Res Inc High-frequency antenna
US2469209A (en) * 1946-04-19 1949-05-03 Gen Electric Single-ended antenna system
DE846571C (en) * 1951-03-30 1952-08-14 Sihn Kg Wilhelm Jun Folded dipole antenna with variable wave impedance
DE867256C (en) * 1951-04-29 1953-02-16 Max Engels Fa Ultra short wave antenna
GB707573A (en) * 1951-05-25 1954-04-21 Telerection Ltd Improvements in or relating to short-wave radio aerials particularly for television and short-wave reception

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE356248C (en) * 1922-07-18 Bruno Rosenbaum Dipl Ing Loop antenna for wireless character transmission
US1851178A (en) * 1923-06-18 1932-03-29 Lillian Louise Hammond Antenna
US2059299A (en) * 1933-06-01 1936-11-03 Rca Corp Short wave tuner
US2324462A (en) * 1941-11-15 1943-07-13 Gen Electric High frequency antenna system
US2447879A (en) * 1945-11-19 1948-08-24 Gen Electric Antenna
US2467961A (en) * 1946-02-20 1949-04-19 Electronies Res Inc Antenna
US2469209A (en) * 1946-04-19 1949-05-03 Gen Electric Single-ended antenna system
US2467962A (en) * 1947-01-28 1949-04-19 Electronies Res Inc High-frequency antenna
DE846571C (en) * 1951-03-30 1952-08-14 Sihn Kg Wilhelm Jun Folded dipole antenna with variable wave impedance
DE867256C (en) * 1951-04-29 1953-02-16 Max Engels Fa Ultra short wave antenna
GB707573A (en) * 1951-05-25 1954-04-21 Telerection Ltd Improvements in or relating to short-wave radio aerials particularly for television and short-wave reception

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3284801A (en) * 1964-01-15 1966-11-08 John J Bryant Large loop antenna
US3576567A (en) * 1967-07-11 1971-04-27 Edward H Shively Circularly polarized broadcast antenna
DE3220989A1 (en) * 1981-06-05 1982-12-30 Tokyo Shibaura Denki K.K., Kawasaki, Kanagawa AERIAL DEVICE WITH A BASE PLATE AND A FRAME-SHAPED ANTENNA ELEMENT
US4647937A (en) * 1981-06-05 1987-03-03 Tokyo Shibaura Denki Kabushiki Kaisha Antenna apparatus with tuned loop
US5072233A (en) * 1990-07-20 1991-12-10 Zanzig Gary R Loop antenna with integral tuning capacitor
FR2699739A1 (en) * 1992-12-22 1994-06-24 France Telecom Omnidirectional and multipolarization antenna.
EP0604304A1 (en) * 1992-12-22 1994-06-29 France Telecom Multi-polorized omnidirectionnal antenna

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