US3581249A - Miniature helical resonators - Google Patents

Miniature helical resonators Download PDF

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Publication number
US3581249A
US3581249A US794332*A US3581249DA US3581249A US 3581249 A US3581249 A US 3581249A US 3581249D A US3581249D A US 3581249DA US 3581249 A US3581249 A US 3581249A
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US
United States
Prior art keywords
coil
posts
base
longitudinal axis
threaded
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US794332*A
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English (en)
Inventor
Frederick E Spangler
Henry A Schaefer
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General Electric Co
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General Electric Co
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Publication date
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Publication of US3581249A publication Critical patent/US3581249A/en
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F21/00—Variable inductances or transformers of the signal type
    • H01F21/02—Variable inductances or transformers of the signal type continuously variable, e.g. variometers

Definitions

  • a cup-shaped dielectric tuning element is threaded in the receptacle for movement toward and away from the coil, and a metallic can is positioned around the posts.
  • the capacity between the coil and can, and hence the resonant frequency of the resonator, is varied by adjusting the position of the tuning element relative to the coil.
  • Our invention relates to an improved coil construction, and particularly to an improved coil construction that provides a tunable resonator for relatively high radio frequencies.
  • Helical coils particularly helical coils used for resonators find many applications in radio apparatus. Such coils represent a considerable portion of the cost of radio apparatus, and hence ways are constantly being sought to make such coils as inexpensive as possible. This is particularly true as the frequency of the radio apparatus increases, since such an increased frequency means a physically smaller coil that is more difficult to manufacture.
  • an object of our invention is to provide a new and improved coil construction for radio frequency apparatus.
  • Another object of our invention is to provide an improved coil construction that is relatively easy to manufacture, and hence is relatively inexpensive.
  • a radio coil be easily coupled to an electrical circuit, particularly when the coil is used as a resonator.
  • the coil should have means for tuning such as by means of a capacitor, so that its resonant frequency can be adjusted.
  • the coil construction, with its capacitor should be mechanically small or compact and structurally strong.
  • Another object of our invention is to provide an improved construction which permits a'radio coil to be easily coupled to an electrical circuit.
  • Another object of our invention is to provide an improved coil construction having a tunable capacitor for adjusting the resonant frequency of the coil.
  • Still another object of our invention is to provide an improved construction that provides a radio coil which is relatively compactand mechanically strong.
  • a coil construction having a base of dielectric material.
  • a coil is wound about a longitudinal axis and positioned on the base so that the longitudinal axis extends upward from the base.
  • the coil is wound on a dielectric form.
  • a plurality of posts preferably four arranged at the corners of a square, extend upward from the base around the coil. These posts have threads on their inner faces to form a threaded receptacle.
  • a tuning element that is preferably cup-shaped is formed of dielectric material with external treads for fitting in the threaded receptacle, and is threadedly positioned in the receptacle.
  • the tuning element can be moved toward or away from the coil by rotation of the tuning element in its threaded receptacle.
  • a metallic element is positioned around the posts, preferably in the form of a can, and connected to one end of the coil.
  • the amount of dielectric material between the coil and conductive element is varied, so that the capacity associated with the coil is also varied.
  • This variable capacity can be used to adjust the resonant frequency of the coil to a selected value.
  • the coil may be coupled to electrical circuits by a window or opening in the conductive element, or by other suitable means.
  • FIG. 1 shows an exploded perspective view of a coil construction in accordance with our invention
  • FIG. 2 shows a longitudinal cross-sectional view of our coil construction taken along a plane passing through diagonally opposite posts
  • FIG. 3 shows one equivalent electrical circuit of our coil construction of FIGS. 1 and 2.
  • our coil construction comprises a square base 10 having four posts 11 a, 11 b, 11 c, 11 d extending upward from the base 10.
  • the posts 11 a, 11 b, 11 c, 11 d are preferably formed integrally with the base 10 from a suitable dielectric material, such as polyphenylene oxide.
  • the posts 11 a, 11 b, 11 c, 11 d are provided with threads 13 on their inner faces. The threads 13 are arranged so that they are positioned on a common helix to form a threaded receptacle.
  • the base 10 is provided with a suitable hole or opening 14 for receiving a coil form 16.
  • the coil form 16 is a generally cylindrical structure having a helical groove or thread 17 extending along most of its length.
  • the coil form 16 is made of any suitable dielectric material, such as the polyphenylene oxide used for the base [0.
  • a slot 18 is formed in the lower end of the coil form 16, and a longitudinal hole 19 is positioned at the upper end.
  • a plurality of diametrically positioned slots 20 are positioned around the hole 19 at the upper end.
  • a tuning element 25 is provided of suitable dielectric material, such as the polyphenylene oxide used for the other parts.
  • the tuning element 25 is cylindrical in shape and preferably cup-shaped, and is provided with external threads 26 of a size and pitch to fit the threads 13 in the posts 11 a 11 b, 11 c, 11 d.
  • the tuning element 25 may also be provided with a slot or other opening 27, so that it can be rotated with a tool.
  • a conductive element or can 30 is positioned around the posts 11 a, 11 b, 11 c, 11 dto protect the coil construction, and also to provide a voltage reference point sothat the coil can be tuned.
  • the can 30 is preferably a square structure, made of suitable material such as copper, having four sides and a bottom as shown in FIG. 1.
  • the can 30 may also be provided with a plurality of tabs 31 for holding the can 30 on the base 10.
  • the he can 30 may also be provided with a coupling hole or opening or window 32 (indicated in dashed lines in H0. 1) to permit the coil on the coil form 16 to be coupled to an electrical circuit.
  • other coupling elements may be provided if desired.
  • the coil When a coil is constructed in accordance with our invention, the coil is wound on the coil form 16.
  • the coil form 16 and wound coil is then inserted in the hole 14 in the base, as shown in F IG. 2.
  • the tuning element 25 is then threaded into the receptacle formed by the threads 13, and the conductive element or can 30 is then placed over or around the posts 11 a, 11 b, 11 c, 11 d, and its tabs 31 bent down against the outer surface of the base 10 to hold the can 30 in position.
  • the lower end 22 a of the wire 22 is then soldered or fastened to one of the tabs 31 of the can 30.
  • the top of the can 30 may be provided with a suitable hole or opening 33 to permit a tool to be inserted inside the can 30 and into the slot 27 in the tuning element 25.
  • FIG. 3 shows an equivalent electrical circuit of such a tunable coil or resonator. ln H6. 3, the coil is illustrated by an inductive symbol, and is shown connected to the can 30 by the tab 31.
  • the variable capacitive element is diagrammatically illustrated as being connected between the can 30 and the upper end 22 b of the coil, although it is to be understood that this capacitive element actually exists between all of the coil turns and the can 30. However, we have shown the capacitive element connected to the end 22 b, since the greatest capacity change takes place at this end 22 b because of the shape or configuration of the tuning element 25.
  • the coil construction was intended to be used as a frequency of 450 megacycles.
  • the can 30 had a square cross section measuring 0.375 by 0.375 inches, and was 0.66 inch high.
  • the coil form 16 had a length of 0.31 inch, and a diameter of 0.25 inch.
  • the coil form 16 was wound with 7 %turns which provided a coil having an unloaded Q of 425 at a frequency of 470 megacycles.
  • the coil could be tuned between 420 and 470 megacycles, with a 0.1 inch travel of the tuning element.
  • our construction is small, and easily built. In addition, it provides a fairly wide range of tuning, and is rugged in its construction.
  • the coil form 16 may have various types of slots or notches to receive and hold the ends of the wire forming its coil.
  • the tuning element 25 may have other shapes, although we prefer a cup-shaped element. And, various types of openings or holes may be used for receiving a tool to adjust the tuning element. Therefore, while the invcntion has been described with reference to a particular embodiment, it isto be understood that modifications may be made without departing from the spirit of the invention or from the scope of the claims.
  • An improved coil construction for radio frequency apparatus comprising:
  • At least three posts of dielectric material positioned on said base around said coil, saidposts extending upwardly from said base in a direction generally parallel to said longitudinal axis, and said posts being threaded on an inner face thereof to provide a threaded receptacle around said longitudinal axis;
  • a tuning element of dielectric material having external threads arranged to fit said threaded receptacle provided by said posts, said tuning element being rotatable in said threaded receptacle to move along said longitudinal axis to vary the amount of dielectric material between said coil and said conductive can.
  • the improved coil construction of claim 1 comprising four substantially similar dielectric posts respectively positioned at the four corners of a square on said base, said posts extending upwardly from said base in a direction generally parallel to said longitudinal axis and being threaded on an inner face to provide a threaded receptacle around said longitudinal axis.
  • the improved coil construction of claim 1 comprising four substantially similar dielectric posts respectively positioned at the four corners of a square on said base, said posts extending upwardly from said base in a direction generally parallel to said longitudinal axis, and said posts being threaded on an inner face to provide a circular threaded receptacle concentrically positioned around said longitudinal axis.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Control Of Motors That Do Not Use Commutators (AREA)
  • Magnetic Resonance Imaging Apparatus (AREA)
  • Coils Or Transformers For Communication (AREA)
US794332*A 1969-01-27 1969-01-27 Miniature helical resonators Expired - Lifetime US3581249A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US79433269A 1969-01-27 1969-01-27

Publications (1)

Publication Number Publication Date
US3581249A true US3581249A (en) 1971-05-25

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Application Number Title Priority Date Filing Date
US794332*A Expired - Lifetime US3581249A (en) 1969-01-27 1969-01-27 Miniature helical resonators

Country Status (5)

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US (1) US3581249A (de)
JP (1) JPS552723B1 (de)
DE (2) DE2003186A1 (de)
GB (1) GB1269322A (de)
SE (1) SE354391B (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101854A (en) * 1977-01-28 1978-07-18 The United States Of America As Represented By The Secretary Of The Army Tunable helical resonator
US4284966A (en) * 1979-12-21 1981-08-18 Motorola, Inc. Wide bandwidth helical resonator filter
US4385279A (en) * 1981-08-04 1983-05-24 Motorola, Inc. Tunable helical resonator
US6031436A (en) * 1998-04-02 2000-02-29 Space Systems/Loral, Inc. Single and dual mode helix loaded cavity filters
US6111554A (en) * 1997-01-07 2000-08-29 Galtronics Ltd. Helical antenna element
US20080245368A1 (en) * 2007-04-02 2008-10-09 Dunsmore Thomas J High frequency oscillation respiratory therapy
US20110102103A1 (en) * 2009-10-30 2011-05-05 Hon Hai Precision Industry Co., Ltd. Radio frequency filter
US8471664B1 (en) * 2012-04-24 2013-06-25 Zippy Technology Corp. Transformer without coil racks

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3146168C2 (de) * 1981-11-21 1986-07-24 Neosid Pemetzrieder Gmbh & Co Kg, 5884 Halver Induktives Bauelement, insbesondere Spule für hohe und sehr hohe Frequenzen sowie Verfahren zur Herstellung eines solchen Bauelementes
JPH0343683U (de) * 1989-08-30 1991-04-24
DE9014920U1 (de) * 1990-10-29 1991-01-10 Neosid Pemetzrieder Gmbh & Co Kg, 5884 Halver Induktives Bauelement, insbesondere induktives Miniatur-Bauelement mit Kapazitätsabstimmvorrichtung

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2227846A (en) * 1935-05-11 1941-01-07 Rca Corp High frequency coil
US2753530A (en) * 1950-11-04 1956-07-03 Itt High q. frequency tuner
US2889522A (en) * 1953-08-05 1959-06-02 Gen Instrument Corp Tuned transformer assembly
US3060394A (en) * 1958-12-20 1962-10-23 Maeda Hisao Radio transformer
US3092796A (en) * 1959-05-07 1963-06-04 Maeda Hisao Intermediate frequency transformer
US3409850A (en) * 1965-10-28 1968-11-05 Oshima Masaomi Miniature inductance device for communication

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2227846A (en) * 1935-05-11 1941-01-07 Rca Corp High frequency coil
US2753530A (en) * 1950-11-04 1956-07-03 Itt High q. frequency tuner
US2889522A (en) * 1953-08-05 1959-06-02 Gen Instrument Corp Tuned transformer assembly
US3060394A (en) * 1958-12-20 1962-10-23 Maeda Hisao Radio transformer
US3092796A (en) * 1959-05-07 1963-06-04 Maeda Hisao Intermediate frequency transformer
US3409850A (en) * 1965-10-28 1968-11-05 Oshima Masaomi Miniature inductance device for communication

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4101854A (en) * 1977-01-28 1978-07-18 The United States Of America As Represented By The Secretary Of The Army Tunable helical resonator
US4284966A (en) * 1979-12-21 1981-08-18 Motorola, Inc. Wide bandwidth helical resonator filter
US4385279A (en) * 1981-08-04 1983-05-24 Motorola, Inc. Tunable helical resonator
US6111554A (en) * 1997-01-07 2000-08-29 Galtronics Ltd. Helical antenna element
US6031436A (en) * 1998-04-02 2000-02-29 Space Systems/Loral, Inc. Single and dual mode helix loaded cavity filters
US20080245368A1 (en) * 2007-04-02 2008-10-09 Dunsmore Thomas J High frequency oscillation respiratory therapy
US20110102103A1 (en) * 2009-10-30 2011-05-05 Hon Hai Precision Industry Co., Ltd. Radio frequency filter
US8723622B2 (en) * 2009-10-30 2014-05-13 Hon Hai Precision Industry Co., Ltd. Radio frequency filter
US8471664B1 (en) * 2012-04-24 2013-06-25 Zippy Technology Corp. Transformer without coil racks

Also Published As

Publication number Publication date
GB1269322A (en) 1972-04-06
DE7002406U (de) 1970-07-30
DE2003186A1 (de) 1970-08-20
SE354391B (de) 1973-03-05
JPS552723B1 (de) 1980-01-22

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