WO1998043255A1 - Bobines d'arret hf comprenant des inducteurs couples en parallele - Google Patents

Bobines d'arret hf comprenant des inducteurs couples en parallele Download PDF

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Publication number
WO1998043255A1
WO1998043255A1 PCT/US1998/005365 US9805365W WO9843255A1 WO 1998043255 A1 WO1998043255 A1 WO 1998043255A1 US 9805365 W US9805365 W US 9805365W WO 9843255 A1 WO9843255 A1 WO 9843255A1
Authority
WO
WIPO (PCT)
Prior art keywords
core
cores
choke
wound
wire coil
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.)
Ceased
Application number
PCT/US1998/005365
Other languages
English (en)
Inventor
Arthur Sherman Morris, Iii
Steven Bryan O'steen
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Raychem Corp
Original Assignee
Raychem Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Raychem Corp filed Critical Raychem Corp
Priority to AU65672/98A priority Critical patent/AU6567298A/en
Priority to NZ507014A priority patent/NZ507014A/en
Publication of WO1998043255A1 publication Critical patent/WO1998043255A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F17/00—Fixed inductances of the signal type
    • H01F17/04—Fixed inductances of the signal type with magnetic core

Definitions

  • This invention relates to radio frequency (RF) chokes, and more particularly to a device for separating a single phase AC power signal from a broadband signal carried on the same conductor, the device having a higher inductance and a higher current carrying capacity than RF chokes heretofore available.
  • RF radio frequency
  • RF chokes are commonly referred to as RF chokes. Since the impedance, i.e. reactance, of an inductor increases with frequency, RF chokes are designed to exhibit a relatively high impedance to signals in the RF frequency range, commonly above 5MHz , a relatively low impedance to the AC power signal, and to minimize resonance effects at the higher frequencies.
  • Standard cylindrical chokes commonly include an insulated wire coiled into a helix.
  • the inductance level needed to present a sufficiently high impedance at the RF frequencies is achieved by introducing a magnetic core into the center of the coil .
  • the magnetic core is commonly comprised of ferrite material.
  • Other linear magnetic materials e.g. powdered iron and laminated steel may also be used.
  • Ferrite cores are commonly preferred for high frequency, e.g. greater than about 1 MHZ, applications.
  • the properties of the magnetic core will change above a saturation level of magnetic flux density. This limits the current carrying capacity of the RF choke to a level below the saturation level of the core.
  • Parasitic capacitance can result from wrapping a conductor around a core.
  • the effect of parasitic capacitance electrically coupled in series with the inductor is to form a series C circuit having a resonant frequency, with a concomitant sharp loss in impedance at the resonant frequency.
  • the Q of the resonant LC circuits may be quite high.
  • the inductance of an RF choke can be raised by increasing the number of turns in the coil. However, this can lower the resonant frequency into the band of operation. Reducing the number of turns in the coil to reduce the resonance may reduce the inductance to a value that makes the RF choke no longer useful in the frequency range of interest .
  • a resistor may be electrically coupled between specified turns of the inductor coil .
  • the spacing between the individual conductor coils may be increased to decrease parasitic capacitance and damp the resonance.
  • the inductance of an RF choke is dependent on the coil spacing to the second order. Therefore, an effect of spreading out the coil spacing can be to reduce the inductance of the coil .
  • Air coils of one or more turns may be included to avoid saturating the core.
  • This approach requires a compromise at the lower frequencies since much less inductance can be obtained.
  • the diameter of the core may be increased to lower the flux density for a given current level. However, this increases the wire length and causes high frequency resonance problems.
  • the invention provides an RF choke comprising first and second cores.
  • an RF choke of the invention comprises a first wire coil wound upon the first core; and a second wire coil wound upon the second core; wherein: the two cores are aligned substantially parallel; the first wire coil and the second wire coil are wound in opposite directions around the first and second cores; and the first wire coil and the second wire coil are electrically coupled in parallel.
  • an RF choke of the invention comprises a wire coil wound upon the cores, wherein: the two cores are aligned substantially parallel; the wire coil forms at least two successive windings in series with each other, with a first winding wound in one direction around the first core and a second winding wound in the opposite direction around the second core .
  • cores are preferred for use in RF chokes of the invention, elongate cores having other cross-sections, e.g. polygon, having parallel longitudinal axes, may also be used.
  • the core comprise a low-loss material with a relative magnetic permeability greater than 1.
  • Air or dielectric cores may also be used, in which case the current carrying capacity would be limited by the thermal power limit of the wires rather than core saturation .
  • two cylindrical chokes are placed side by side, each interacts with the fringing magnetic field of the other. Depending on the direction of the windings, the magnetic fields can add or subtract. If the coils are counter wound, so that the magnetic fields add in each core, higher inductance is obtained and much higher currents are feasible. This can be accomplished in at least two ways: 1) two independent but counter-wound parallel connected cores located closely together, and 2) two cores wound in a figure-eight pattern. The two approaches yield one effective choke on two counter- wound cores .
  • the inductance of a choke comprising two cylindrical cores increases as the cores are moved closer together.
  • the wire-wound cores are placed in juxtaposition.
  • the cores are placed substantially two wire thicknesses apart .
  • the cores are placed substantially one wire thickness apart .
  • one present commercial line of outdoor cable TV taps includes a choke that is made on a .164 inch diameter by .873 inch long ferrite core.
  • the choke is wound with 12 turns of 20 gauge wire tightly wound together except for an approximately .050 inch gap in the center, i.e., 5 1/2 turns, then a 1 turn spread, then 5 1/2 more turns.
  • This choke has an inductance of about 2 ⁇ H and is fairly linear up to about 7 amps RMS of 60 Hz current.
  • the choke does have a small hum in a 14 dB 4-way outdoor tap. Above about 7 amps RMS, the peak current saturates the ferrite core and causes significant hum modulation of the RF signal through the tap.
  • An improved RF choke of the invention was made by winding two chokes, one wound identical to the choke used in the tap described above, and the second in the same manner except wound with the opposite pitch. The two chokes were then connected in parallel .
  • the parallel combination provided about 2 ⁇ H inductance, not 1 ⁇ H that a simple parallel element calculation would predict.
  • the RF performance, i.e. return loss and insertion loss, of the tap was unimpaired, and the tap was free of significant hum modulation to greater than 10 amps.
  • RF chokes in accordance with the invention may be used to advantage in applications, e.g., from 800 MHZ cellular telephones through the millimeter wave band.
  • Improved chokes of the invention may be used in bias tees for amplifiers and other active elements where current carrying capability is often a limiting factor.
  • RF chokes of the invention may be employed to advantage both: in applications, including those referenced above, in which the low frequency AC signal is passed, and the high frequency RF signal is filtered in a manner so as to preserve the RF signal for subsequent use; and in applications, e.g. RFI filters, wherein the AC power is passed, and the higher frequency signal is filtered out and not preserved for subsequent use .
  • FIG. 1 is a plan view of a prior art RF choke.
  • FIG. 2 is a plan view of an embodiment of an RF choke of the invention.
  • FIG. 3 is a cross sectional view of the embodiment of an RF choke in FIG. 2 taken along the plane 3-3.
  • FIG. 4 is a plan view of a second embodiment of an
  • FIG. 5 is a cross sectional view of the embodiment of an RF choke in FIG. 4 taken along the plane 5-5. Note that none of the drawings are to scale, including, in particular, the representations of the windings and the spacing of the windings of the wire coils .
  • FIG. 1 is a plan view of a prior art RF choke which is indicated generally by the reference numeral 10.
  • the choke 10 comprises a cylindrical core 12 and a conductor 14 wound on the core 12 to form a winding 18 having a predetermined number of turns .
  • the conductor has an input lead 16 and an output lead 22.
  • Parasitic capacitance between the windings 18 is represented by a capacitor 24 shown electrically coupled between two of the windings.
  • the magnetic field generated by a current I flowing through the conductor is indicated by the pattern generally representing the flux density B.
  • the current I flowing through the winding 18 is the same as the current I flowing in the input lead 16 and out the output lead 22.
  • FIG. 2 is a plan view of an embodiment of an RF choke of the invention which is indicated generally by the reference numeral 30.
  • the choke 30 comprises a first cylindrical core 32, a second cylindrical core 34, and a conductor 36.
  • the first core 32 and second core 34 have the same length and the same diameter.
  • the conductor 36 has an input lead 38, an output lead 46, a first winding 42 and a second winding 44.
  • the first winding 42 and second winding 44 are electrically coupled in parallel, with the parallel combination electrically coupled in series between the input lead 38 and output lead 46.
  • the first winding 42 and second winding 44 are wound in opposite directions about the first core 32 and second core 34, respectively. Since the choke 30 comprises two windings 42, 44 the current flowing through each of the respective windings 42, 44, represented as 1/2, is half of the total current, represented as I, flowing in the input lead 38 and out the output lead 46.
  • a first inductor 52 formed by the combination of the first core 32 and first winding 42 is thus electrically coupled in parallel with a second inductor 54 formed by the combination of the second core 34 and second winding 44.
  • the magnetic field generated by a current I flowing through the choke 30 is indicated by the pattern generally representing the flux density B.
  • each inductor interacts with the fringing magnetic field of the other inductor.
  • FIG. 3 is a cross sectional view of the embodiment of an RF choke in FIG. 2 taken along the plane 3-3.
  • FIG. 4 is a plan view of a second embodiment of an
  • the RF choke of the invention which is indicated generally by the reference numeral 60.
  • the choke 60 comprises a first cylindrical core 62, a second cylindrical core
  • the first core 62 and second core 64 have the same length and the same diameter.
  • the conductor 66 has an input lead 68, an output lead 76, and a winding 72, 72A
  • the winding 72, 72' is wound alternatively around the first core 62 and second core 64, in a figure-eight pattern, and is thereby wound in opposite directions about the first core 62 and second core 64. Since the choke 60 comprises only one winding 72, 72 A the current flowing through the winding 72, 72' is the same as the total current, represented as I, flowing in the input lead 68 and out the output lead 76. The result is a single choke 60 formed on the two counter-wound cores 62, 64. The magnetic field generated by a current I flowing through the choke 60 is indicated by the pattern generally representing the flux density B.
  • FIG. 5 is a cross sectional view of the second embodiment of an RF choke in FIG. 4 taken along the plane 5-5.
  • This view depicts the two cores 62, 64 with the counter wound figure-eight winding pattern, and the direction of current flow in the windings 72, 72' around the two cores 62, 64.
  • the turn-to- turn spacing of the windings on each of the cores in the embodiments of the invention depicted in the FIGS may be selected to obtain a desired turn-to-turn capacitance, in order to adjust the resonant frequencies of the RF chokes.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Coils Or Transformers For Communication (AREA)
  • Particle Accelerators (AREA)
  • Medicines Containing Antibodies Or Antigens For Use As Internal Diagnostic Agents (AREA)
  • Peptides Or Proteins (AREA)

Abstract

L'invention concerne une bobine d'arrêt HF (30) présentant une inductance et une capacité conductrice supérieures à celles des bobines d'arrêt traditionnelles. Deux bobines (42, 44) sont enroulés en sens inverse autour de deux noyaux cylindriques (32, 34), de sorte que les champs magnétiques puissent s'étendre dans les noyaux respectifs, et ce de deux manières au moins: 1) par l'intermédiaire de deux noyaux indépendants mais enroulés en sens inverse, ces noyaux étant proches l'un de l'autre et couplés électriquement en parallèle, et 2) par l'intermédiaire de deux noyaux enroulés en forme de huit. Ces deux approches permettent d'obtenir une bobine d'arrêt efficace sur deux noyaux enroulés en sens inverse.
PCT/US1998/005365 1997-03-21 1998-03-18 Bobines d'arret hf comprenant des inducteurs couples en parallele Ceased WO1998043255A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
AU65672/98A AU6567298A (en) 1997-03-21 1998-03-18 Rf chokes comprising parallel coupled inductors
NZ507014A NZ507014A (en) 1997-03-21 1998-03-18 A gene encoding a novel marker for cancer

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US82184197A 1997-03-21 1997-03-21
US08/821,841 1997-03-21

Publications (1)

Publication Number Publication Date
WO1998043255A1 true WO1998043255A1 (fr) 1998-10-01

Family

ID=25234431

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1998/005365 Ceased WO1998043255A1 (fr) 1997-03-21 1998-03-18 Bobines d'arret hf comprenant des inducteurs couples en parallele

Country Status (5)

Country Link
AR (1) AR012133A1 (fr)
AU (1) AU6567298A (fr)
CO (1) CO4780084A1 (fr)
NZ (1) NZ507014A (fr)
WO (1) WO1998043255A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009008110A1 (de) * 2009-02-09 2010-08-19 Epcos Ag Hochfrequenz-Schwingdrossel

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1401741A (en) * 1972-03-17 1975-07-30 Siemens Ag Chokes
FR2496969A2 (fr) * 1978-05-24 1982-06-25 Girodin Tech Magneto-inductance a haute sensibilite a variation proportionnelle a la valeur du champ magnetique
JPH02201906A (ja) * 1989-01-30 1990-08-10 Murata Mfg Co Ltd チョークコイル
DE4103297A1 (de) * 1990-05-02 1992-08-13 Schulte Uebbing Ernst Dr Vorrichtung zur entstoerung von elektrischen leitungen und geraeten
WO1997019458A1 (fr) * 1995-11-24 1997-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Composant inductif

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1401741A (en) * 1972-03-17 1975-07-30 Siemens Ag Chokes
FR2496969A2 (fr) * 1978-05-24 1982-06-25 Girodin Tech Magneto-inductance a haute sensibilite a variation proportionnelle a la valeur du champ magnetique
JPH02201906A (ja) * 1989-01-30 1990-08-10 Murata Mfg Co Ltd チョークコイル
DE4103297A1 (de) * 1990-05-02 1992-08-13 Schulte Uebbing Ernst Dr Vorrichtung zur entstoerung von elektrischen leitungen und geraeten
WO1997019458A1 (fr) * 1995-11-24 1997-05-29 Telefonaktiebolaget Lm Ericsson (Publ) Composant inductif

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 014, no. 489 (E - 0994) 24 October 1990 (1990-10-24) *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009008110A1 (de) * 2009-02-09 2010-08-19 Epcos Ag Hochfrequenz-Schwingdrossel
US9019042B2 (en) 2009-02-09 2015-04-28 Epcos Ag High-frequency swinging choke

Also Published As

Publication number Publication date
CO4780084A1 (es) 1999-05-26
AR012133A1 (es) 2000-09-27
NZ507014A (en) 2003-08-29
AU6567298A (en) 1998-10-20

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