US2994046A - Rotating coupling device for radio frequency currents, especially for ultrahigh frequency currents - Google Patents

Rotating coupling device for radio frequency currents, especially for ultrahigh frequency currents Download PDF

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Publication number
US2994046A
US2994046A US716239A US71623958A US2994046A US 2994046 A US2994046 A US 2994046A US 716239 A US716239 A US 716239A US 71623958 A US71623958 A US 71623958A US 2994046 A US2994046 A US 2994046A
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United States
Prior art keywords
coupling device
frequency currents
coupling
rotating
band
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Expired - Lifetime
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US716239A
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English (en)
Inventor
Granqvist Carl-Erik
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Svenska AB Gasaccumulator
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Svenska AB Gasaccumulator
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
    • H01P1/00—Auxiliary devices
    • H01P1/06—Movable joints, e.g. rotating joints
    • H01P1/062—Movable joints, e.g. rotating joints the relative movement being a rotation
    • H01P1/066—Movable joints, e.g. rotating joints the relative movement being a rotation with an unlimited angle of rotation
    • H01P1/068—Movable joints, e.g. rotating joints the relative movement being a rotation with an unlimited angle of rotation the energy being transmitted in at least one ring-shaped transmission line located around the axis of rotation, e.g. "around the mast" rotary joint
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H2/00—Networks using elements or techniques not provided for in groups H03H3/00 - H03H21/00
    • H03H2/005—Coupling circuits between transmission lines or antennas and transmitters, receivers or amplifiers

Definitions

  • the present invention relates to a rotating coupling device for radio frequency currents, especially ultra high frequency currents.
  • Such coupling devices are used in many fields within the radio technics.
  • the transfer of high frequency currents received by an antenna to a radio receiver may be mentioned, or the transfer of such currents from a radio transmitter to an antenna, when the antenna is rotating.
  • This is, for instance, the case in different kinds of direction finding apparatus and also for so called rotating radio beacons, especially the so-called speaking radio beacons, and in radar equipment.
  • the present invention refers to a rotating coupling by means of which all of the abovementioned disadvantages are avoided.
  • coaxial, circular rings are used for the rotating coupling device for causing inductive transfer of the electrical radio frequency energy from a fixed system to a rotating system, and the rings are divided into segments separated by means of capacity elements and feeding points so that each segment is less than one quarter of the mean wave-length within the transferred frequency band.
  • FIGS. 1 and 2 show a pair of electrical wiring diagrams for explaining the principal of the invention
  • FIG. 3 and FIG. 4 show a pair of different forms of execution of the arrangement according to the invention
  • FIG. 5 shows a diagram of the attenuation in an arrangement according to the invention.
  • FIG. 1 shows the general arrangement of a coupling circuit in schematic form.
  • the circuit consists in two coils L and L coupled to each other, with a coupling factor K for the dynamic coupling.
  • a condenser C and C In series with each of said coils there is a condenser C and C respectively.
  • the impedance transferred to the input side of the circuit is indicated by Z, and the system is assumed to be loaded at its output side by means of the resistor R.
  • the frequency of the transferred alternating currents is w. In this case the following equation is obtained:
  • the relation impedance: resistance or Z/ R will vary with the square of the frequency. Furthermore, the impedance-resistance-relation will be capacitive for frequencies below the resonance frequency and inductive for frequencies above the resonance frequency. The disadvantage of this, however, can be done away with by introducing a pair of parallel resonance circuits in the manner shown in FIG. 2.
  • the parallel resonance circuit of the primary side consists of the inductance coil L and the condenser C
  • the corresponding circuit on the secondary side consists of the inductance coil L and the condenser C".
  • the magnitude of L and L", respectively, as well as C and C", respectively, is suitably chosen in such a way that each circuit is in resonance at a frequency which could be indicated as the mean frequency of the transferred frequency band.
  • the division between capacity and inductance in the said resonance circuits is thereby determined by the combined reactance of the series resonance circuit and the parallel resonance circuit being as closely equal to zero as possible at the limit frequencies for the transfer frequency band.
  • FIG. 3 the pole about which the rotating coupling device is disposed is indicated by 10.
  • the coils of the coupling device corresponding to the coils L and L in FIGS. 1 and 2, are formed by a pair of coaxial bands 11 and 12, respectively.
  • the series condensers C and C respectively, are in the practical arrangement according to FIG. 3 divided into two condensers 13 and 14 as well as 15 and 16.
  • the input parallel resonance circuit L'C' connected to the receiver when the antenna is used as a receiver antenna, or connected to the transmitter when the antenna is used as a transmitter antenna, consists of the coil 17 and the condenser 18, whereas the output parallel resonance circuit LC" for the side of the coupling device connected to the antenna or the receiver, respectively, is formed by the coil 19 and the condenser 20
  • An arrangement according to FIG. 3 would be possible to use, but it is not idea], because it is unavoidable that there is some capacitive coupling between the bands 11 and 12 and this capacitive coupling will vary with the mutual position of the hands during the rotation. This capacitive coupling, however, can easily be decreased, if the potential is divided more evenly along the length of the bands.
  • the capacitive coupling between the bands may assume a disturbing order of magnitude.
  • the capacitive coupling can be further decreased by providing more than one condenser between different parts of the band 11 or 12, respectively, corresponding to the condensers 21 and 22.
  • parts of the band would then be without any feed of voltage, unless the number of feeding places for the voltage to the bands is increased to a corresponding degree.
  • FIG. 4 shows a modification of the arrangement according to FIG. 3, in which feeding of the bands takes place in two diametrically opposite points, which makes the connection of two series condensers possible, corresponding to the series condensers 21 and 22 of FIG. 3.
  • the two condensers connected on the apparatus side corresponding to the, condenser 23. of FIG. 3 are formed by the condensers 23 and 24, and the two condensers on the antenna side of the coupling, corresponding to the condenser 22 of FIG. 3, are formed by the condenser 25 and 26.
  • the two parallel resonance circuits 17, 13 as well as 19, 20 have been replaced by resonators, consisting of a radiation pipe of a mechanical length of one quarter of a wavelength.
  • the two resonators arranged on the apparatus side of the coupling device are indicated by 27 and 28, respectively, and the two resonators on the antenna side by 29 and 30, respectively.
  • the feeder lines are carried through these resonators in the form of conduits in screened mantels in a known manner, whereby the conductor and the screening mantel function as a coaxial cable in which the screens are connected to ground potential.
  • the two band-formed coils can be divided into a suitable number of sectors, connecting a suitable number of feeding points to them.
  • each sector under all circumstances should be less than one quarter of the mean wave-length of the transferred wave-length band, and the best result is obtained if the length of the sector is about equal to one eighth of the mean wave-length of the transferred frequency band.
  • the band Width is determined by the coupling degree between the two bands 11 and 12 forming the coils. The less the distance between them, the stronger the coupling will be, and the bigger the band width will be. However, the band width cannot be increased to much in this way, because of the small distance between the bands 11 and 12 there would be danger for electrical spark formation occurring. In such case each of the bands could be divided into a number of sectors with a separate feed, but then there will be a decrease in the ctfectivity of the coupling device due to each sector being less than one eighth of the mean wave-length of the band.
  • FIG. 5 shows a diagram for the variation of the loss figure with the tuning frequency of the signal to be transferred in a coupling device according to the invention, as calculated for transferring a frequency band between 215 and 430 mc./s.
  • a coupling device for transfer of high frequency currents between a rotating means and a fixed means comprising substantially circular concentric rings coaxially disposed about said rotating means, at least one of said rings being fixed and at least another of said rings being rotatable with said rotating means condensers dividing each of said rings into sectors of less than one quarter of the mean wave length within the frequency band intended to be transferred, and means for feeding current to each of said sectors.
  • a coupling device including one or more condensers connected in series between said sectors and said feeding means.
  • a coupling device according to claim 3 wherein said resonance means comprise tuned circuits connected in parallel with said feeding means.
  • a coupling device according to claim 5 wherein said feeding means include a coaxial conductor.

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US716239A 1957-03-18 1958-02-19 Rotating coupling device for radio frequency currents, especially for ultrahigh frequency currents Expired - Lifetime US2994046A (en)

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Application Number Priority Date Filing Date Title
SE2994046X 1957-03-18

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US2994046A true US2994046A (en) 1961-07-25

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US716239A Expired - Lifetime US2994046A (en) 1957-03-18 1958-02-19 Rotating coupling device for radio frequency currents, especially for ultrahigh frequency currents

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US (1) US2994046A (enrdf_load_stackoverflow)
DE (1) DE1066638B (enrdf_load_stackoverflow)
FR (1) FR1202276A (enrdf_load_stackoverflow)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3156884A (en) * 1962-04-30 1964-11-10 Aladdin Ind Inc Ultra high frequency tuner having rectilinearly sliding plates providing variable inductance and capacitance
US3914715A (en) * 1974-06-26 1975-10-21 Texas Instruments Inc Coaxial ring rotary joint
US5754220A (en) * 1996-04-26 1998-05-19 Emerson Electric Company Apparatus for inspecting the interior of pipes
WO2001086749A3 (en) * 2000-05-10 2002-04-04 Transense Technologies Plc An improved rotary signal coupler

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2456398A1 (fr) * 1979-05-11 1980-12-05 Thomson Csf Joint tournant multivoies pour equipement de detection electromagnetique

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2274346A (en) * 1938-01-27 1942-02-24 Telefunken Gmbh Frequency selective transmission line
US2401572A (en) * 1943-06-09 1946-06-04 Rca Corp Rotating joint for parallel wire transmission lines
US2405616A (en) * 1943-07-07 1946-08-13 Silver Walter Antenna coupling

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2274346A (en) * 1938-01-27 1942-02-24 Telefunken Gmbh Frequency selective transmission line
US2401572A (en) * 1943-06-09 1946-06-04 Rca Corp Rotating joint for parallel wire transmission lines
US2405616A (en) * 1943-07-07 1946-08-13 Silver Walter Antenna coupling

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3156884A (en) * 1962-04-30 1964-11-10 Aladdin Ind Inc Ultra high frequency tuner having rectilinearly sliding plates providing variable inductance and capacitance
US3914715A (en) * 1974-06-26 1975-10-21 Texas Instruments Inc Coaxial ring rotary joint
US5754220A (en) * 1996-04-26 1998-05-19 Emerson Electric Company Apparatus for inspecting the interior of pipes
WO2001086749A3 (en) * 2000-05-10 2002-04-04 Transense Technologies Plc An improved rotary signal coupler
US20030146812A1 (en) * 2000-05-10 2003-08-07 Anthony Lonsdale Rotary signal coupler
US6838958B2 (en) 2000-05-10 2005-01-04 Transense Technologies Plc Rotary signal coupler

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Publication number Publication date
DE1066638B (enrdf_load_stackoverflow)
FR1202276A (fr) 1960-01-08

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