Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
  • H01P5/10—Coupling devices of the waveguide type for linking dissimilar lines or devices for coupling balanced lines or devices with unbalanced lines or devices
  • H01P5/103—Hollow-waveguide/coaxial-line transitions
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
  • H01P5/00—Coupling devices of the waveguide type
  • H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
  • H01P5/085—Coaxial-line/strip-line transitions

Definitions

• the present invention relates to a coupling method and a coupler implementing said method for separating dual polarization bands propagating for example in a horn antenna.
• orthogonal mode junction couplers called OMJ according to the acronym "Ortho-Mode Junctions" to separate double polarization bands.
• these orthogonal mode junction couplers conventionally consist of a waveguide supply section comprising orthogonal feed points placed along the axis of the coupler, said points being offset along the axis of the coupler.
• the feed points are generally made by means of plugs, grooves or any other equivalent means well known to those skilled in the art.
• This type of couplers has the disadvantage of providing poor isolation between the different input ports of the power points that are close to each other.
• this type of coupler has an asymmetry that provides a degradation of the purity of the modal network due to the excitation of higher order modes.
• One of the aims of the invention is therefore to remedy all these disadvantages by proposing a coupling method and a coupler implementing said method providing a weak coupling between the ports for medium to wide frequency bands without requiring a circuit external compensation.
• a method for coupling orthogonal mode junction means and means of wavelength ⁇ said method being remarkable in that it consists in feeding capacitively a conductive structure integral with the waveguide by means of a plug projecting inside the waveguide and extending between a short circuit of said waveguide and the conductive structure.
• Another object relates to a coupler with orthogonal mode orthogonal junction means of a waveguide with wavelength ⁇ remarkable in that it comprises a plug projecting from the waveguide and extending between a short circuit of the waveguide and a conducting structure acting as a dipole radiating at the wavelength ⁇ / 2 excited at its central point by the plug.
• Said plug consists of a conductive rod electrically insulated from the waveguide and capacitively feeding the conductive structure.
• the conductive structure consists of two fins respectively C-shaped or U extending symmetrically on either side of the plane of symmetry of the waveguide, each fin having a first branch secured to the waveguide and extending above the plug and parallel thereto towards the plane of symmetry of said waveguide and a second leg extending parallel to the first leg above said waveguide, said legs being connected by a vertical base extending perpendicular to the plug.
• the distance separating the short circuit from the waveguide of the lower plug is approximately equal to a quarter of the wavelength ⁇ of the waveguide.
• the distance separating the lower plug from the upper plug is also approximately equal to a quarter of the wavelength ⁇ of the waveguide.
• the upper plug using a virtual short circuit located below the latter in the waveguide (made for example by means of a rod parallel to said plug connected at both ends to the walls of the waveguide).
• the coupler comprises a filter positioned between the two orthogonal excitation assemblies. (Filters made for example by means of rods connected at both ends to the walls of the waveguide).
• Figure 1 is an exploded perspective view of the coupler according to the invention mounted with a horn antenna
• Figure 2 is a schematic radial sectional view of the coupler according to the invention; The invention shown in FIG. 1.
• An OMJ broadband and medium-range coupler according to the invention will be described below in order to separate orthogonal double polarization bands from a coaxial circular circular horn or charged with a dielectric cone.
• the coupler according to the invention consists of a cylindrical waveguide 1 comprising a coaxial cylindrical cavity 2 whose bottom forms a short circuit 3 of said waveguide 1.
• Said waveguide comprises on its side wall an input port 4 from which extends a plug 5 consisting of a conductive rod electrically insulated from the waveguide, said conductive rod 5 being electrically isolated from radio frequencies and not current batchwise.
• This conducting rod 5 opens into the cylindrical cavity 2 of the waveguide 1 extending diametrically in said cavity.
• said waveguide 1 comprises near its upper end a conductive structure 6 acting as a dipole radiating at the wavelength ⁇ / 2.
• This conductive structure 6 consists of two fins 7 respectively C-shaped or U extending symmetrically on either side of the axis of revolution of the waveguide 1, and more precisely symmetrically on both sides of the plane of symmetry of the waveguide 1 extending orthogonally to the conducting rod 5 and passing through the axis of revolution of said waveguide 1
• Each fin 7 comprises a first so-called lower branch 8 integral with the waveguide 1 and extending above the conducting rod 5 and parallel to the latter towards the plane of symmetry of said waveguide 1 and a second upper branch. 9, shorter than the lower branch 8, extending parallel to the lower branch 8 above the latter, said branches 8 and 9 being connected by a vertical base 10 extending perpendicularly to the conducting rod 5.
• the conductive structure 6 will advantageously be obtained in a metallic material.
• the latter comprises a filter positioned between the two orthogonal excitation structures.
• the filter may consist of several conductive rods at the ends are connected to the waveguide or any other equivalent means well known to those skilled in the art without departing from the scope of the invention.
• the conductive rod 5 capacitively feeds the conductive structure 6 in such a way that an excitation current flows through the upper branches 9 of the conductive structure 6, said excitation currents being represented by arrows in FIG.
• the excitation currents of the upper branches 9 correspond to the current distribution on an equivalent dipole.
• an antenna horn 12 comprising at its base a flange 13 provided with hole 14 may be fixed to the end of the coupler by means of screws 15 cooperating with tapped holes 16 made on the upper edge of the waveguide 1.
• Such a coaxial coupler operating on a medium to wide orthogonal mode junction frequency band provides low coupling between the ports so that an external compensating circuit is not required.
• the coupler according to the invention may be obtained according to a precision milling method well known to those skilled in the art or a method of manufacturing a multi-layer printed circuit, said multi-layer printed circuit being integrated within a waveguide, without departing from the scope of the invention.
• orthogonal mode orthogonal junction coaxial coupler according to the invention can be adapted for any other application well known to those skilled in the art and that the examples which the We have just given no limitation as to the fields of application of the invention.

Landscapes

• Waveguide Aerials (AREA)
• Optical Integrated Circuits (AREA)
• Waveguide Switches, Polarizers, And Phase Shifters (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=38007335

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Cited By (1)

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Citations (5)

Family Cites Families (7)

• 2006
  • 2006-10-24 FR FR0609334A patent/FR2907600B1/fr not_active Expired - Fee Related
• 2007
  • 2007-10-18 US US12/446,973 patent/US8125294B2/en active Active
  • 2007-10-18 EP EP07821500A patent/EP2092595A1/de not_active Withdrawn
  • 2007-10-18 WO PCT/EP2007/061135 patent/WO2008049778A1/fr not_active Ceased

Patent Citations (5)

Non-Patent Citations (1)

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