(19)
(11)EP 2 601 706 B1

(12)EUROPEAN PATENT SPECIFICATION

(45)Mention of the grant of the patent:
10.09.2014 Bulletin 2014/37

(21)Application number: 11738972.6

(22)Date of filing:  28.07.2011
(51)International Patent Classification (IPC): 
H01P 1/06(2006.01)
H01P 1/16(2006.01)
(86)International application number:
PCT/EP2011/003800
(87)International publication number:
WO 2012/016665 (09.02.2012 Gazette  2012/06)

(54)

POWER DUAL-BAND ROTARY JOINT OPERATING ON TWO DIFFERENT BANDS

DUALBAND-DREHVERBINDUNG MIT BETRIEB AUF ZWEI VERSCHIEDENEN FREQUENZBÄNDERN

JOINT ROTATIF ÉLECTRIQUE BIBANDE FONCTIONNANT SUR DEUX BANDES DE FRÉQUENCES DIFFÉRENTES


(84)Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME

(30)Priority: 03.08.2010 IT AP20100011

(43)Date of publication of application:
12.06.2013 Bulletin 2013/24

(73)Proprietor: G.E.M. Elettronica S.r.L.
63074 San Benedetto del Tronto (IT)

(72)Inventors:
  • MORINI, Antonio
    I-60121 Ancona (IT)
  • MALASPINA, Vincenzo
    I-63846 Monte Gilberto (IT)
  • PANICHI, Paolo
    I-63066 Grottammare (IT)

(74)Representative: Statti, Francesco 
Isea S.R.L. Via G. Carducci, 6
62012 Civitanova Marche
62012 Civitanova Marche (IT)


(56)References cited: : 
EP-A2- 1 369 955
US-A- 3 026 513
US-A- 4 558 290
JP-A- 9 023 110
US-A- 3 715 688
US-A1- 2010 123 529
  
      
    Note: Within nine months from the publication of the mention of the grant of the European patent, any person may give notice to the European Patent Office of opposition to the European patent granted. Notice of opposition shall be filed in a written reasoned statement. It shall not be deemed to have been filed until the opposition fee has been paid. (Art. 99(1) European Patent Convention).


    Description

    Field of invention



    [0001] The present invention relates in general to radar systems, and more particularly pertains to the field of dual-band radars, which can operate on two different frequency carriers, which in turn correspond to different waveguides as well, for instance, on the X band (8-12.4 GHz, WR90 waveguides) and on Ka (26-40 GHz, WR28 waveguides). The first lower frequency is used for the detection of long distance obstacles. The higher frequency is used for the focalization of the obstacle, when it is approaching. For such systems, the rotary joint is an essential component, as it connects the transmitters to the antennas which are on a rotating support, in such a way that it can perform an azimuth scanning of the surrounding space.

    [0002] The rotary joint must connect two couples of rectangular waveguides of different cross-sections and, correspondingly, working frequency, in a way that each couple can rotate with respect to the other, without affecting the return loss on each band (higher than 20 dB, on both bands), guaranteeing high isolation between waveguides operating at different frequencies (Isolation higher than 60 dB), small insertion loss (lower than 1dB on both bands), immunity of the performance with respect to rotation angle (WOW smaller than 0.5 dB) and, finally high peak power capability (in excess of 72 dBm).

    Background



    [0003] There are a lot of single- band rotary joints available on the market:

    [1] D.G. de Mesquita, A.G. Bailey, "A Symmetrically Excited Microwave Rotary Joint" IEEE Trans. Microwave Theory and Tech., vol. 18, No. 09, pages 654-656, Sep. 1970;

    [2] Smirnov, A.V. ,Yu, D.U. L.,"Symmetrized coupler converting circular waveguide TM01 mode to rectangular waveguide TE10 mode", US Patent No. 20080068110, 2008;

    [3] Tavassoli Hozouri, Behzad, "Mode transducer structure", US Patent No. 7446623, 2008;

    [4] Fisher W. Clifford, "Radar rotary joint", US Patent No. 4654613, 1987;

    [5] Ching-Fang Yu and Tsun -Hsu Chang, "High-Performance Circular TE01-Mode Converter", IEEE Trans. Microwave Theory and Tech., vol. 53, No. 12, pages 3794-3798, Dec. 2005;

    [6] Y. Aramaki, N. Yoneda, M. Miyazaki, Moriyasu, A. Iida, I. Naito, T. Horie, Y. Yutaka, "Rotary joint", US Patent No. 7091804, 2006.



    [0004] All these devices are formed by a couple of junctions (otherwise called transducers) between a cylindrical and a rectangular waveguide connected through a bearing mechanism in such a way that a junction can rotate with respect to the other. The two parts are called stator and rotor, respectively. The junction is conceived in such a way that only the lower order mode with a azimutal symmetry is excited in the cylindrical waveguide, and the transmission does not depend on the reciprocal angle between the two junctions.

    [0005] This is also the simplest case, as the coaxial waveguide works in monomodal region. On the other hand, a millimeter frequency, coaxial waveguide presents high losses and expensive manufacturing costs. In addition, when specifications on power handling capability are more stringent, solutions other than coaxial waveguides must be chosen [1]. A great improvement is achieved by using a circular waveguide as the rotating part. In that case, however, the waveguide must operate under symmetrical modes, exploiting for example TM01 or TE01, which are the lowest order ones. Such a requirement is needed to obtain a structure that is symmetrical not only mechanically but also electrically. The issue is, of course, to prevent the fundamental modes TE11 (with vertical and horizontal polarization, V and H) from being excited, since that would make transmission sensitive to rotation angle.

    [0006] For this reason, on the basis of symmetry, many transducers were invented, aimed at exciting only one mode (TM01 [2] - [5] or TE01 [6]), though not the fundamental one, or, alternatively the TE11 mode, circularly polarized:

    [7] O.M. Woodward, "A Dual-Channel Rotary Joint For High Average Power Operation", IEEE Trans. Microwave Theory and Tech., Vol .18, no. 12, pages 1072-1077, Dec 1970;
    in such a way that the conversion is independent of the angle.



    [0007] In order to achieve this goal, there are the following alternatives:
    1. 1) Coaxial waveguide, operating on the fundamental TEM mode;
    2. 2) Circular waveguide, operating on the TM01 mode, which is the lowest order mode having azimutal symmetry. Unfortunately, the TM01 mode is not the fundamental one, because both TE11V and TE11H mode have a lower cut-off frequency;
    3. 3) Circular waveguide operating on the TE11 mode with circular polarization (RHCP or LHCP). This solution requires a couple of polarizers, which make the device more involved. Typically, when the rotary joint operates on a single band, the first option is preferred. On the other hand, when dual-band operating mode is required, and the working frequencies belong to different waveguide bands (I/O), the usage of a common coaxial waveguide suffers from several drawbacks, mostly due to the need of reducing the coaxial section in such a way that it is monomodal on the upper band thus increasing losses and lowering the "power handling capability". In addition, the realization of the choke providing electrical continuity at the level of the break, necessary to make the rotation possible, is difficult because it must work on both bands.


    [0008] An alternative solution is the use of a circular waveguide, oversized in such a way that at least two modes with azimuthal symmetry can propagate (circularly polarized TE11 and TM01 in:

    [8] S.Ghosh, L.C. Da Silva, "Waveguide rotary joint and mode transducer structure therefor", US Patent No. 5442329, 1995 for "Antenna Feed Systems", Artech House, Norwood, MA, 1993; and TM01 and TE01 in:

    [9] D. A. MacNamara and L. T. Hildebrand, "Fullwave analysis of noncontacting rotary joint choke section using the generalized scattering matrix (GSM) approach", IEE Proc. - Microwave, antennas Propagation, vol. 150 No. 1, Feb. 2003, pages 5-10.



    [0009] The two modes are separated, being mutually orthogonal, thus providing connection for the two bands. Even in this case, one of the main issues concerns the choke, which has to work at frequency 1 for mode 1 and at frequency 2 for mode 2.

    [0010] The two TE11 V and H circular waveguide lower order modes are prevented by a suitable choice of the symmetry of the transducers.

    [0011] It must be noted that in both cases, the azimuthal symmetry waveguide cannot be mechanically continuous: a break is necessary to make possible the rotation of the rotor with respect to the stator. On the other hand, the cut must be designed in a way that it does not permit field leakage. As a matter of fact, this circumstance would increase the insertion loss. The electrical continuity is restored by the insertion, at the level of the cut, of a suitable microwave device called a 'choke', formed by a combination of coaxial and λ/4 radial lines. The impedance transformation is designed in such a way that even though there is a cut there is infact a electromagnetic continuity.

    [0012] The closest prior art to the present invention is considered:

    [10] the US patent No. 3 026 513 A (Kurtz Louis) which discloses a rotary joint, comprising first and second transducers, each transducer connecting two rectangular waveguides to a nested coaxial waveguide. The transducers are connected through the nested waveguides.
    The subject matter claimed by the present invention differs from this known rotary joint in that the waveguides operate on different frequency bands.
    US 3 026 513 does also not mention the chokes integrated in the nested waveguides and the other technical details present in claim 1 with regard to the nested coaxial waveguide, which improve the electrical properties of the dual-band rotary joint.


    Disclosure of invention



    [0013] The present invention would like to overcome the issues discussed above, by using a dual-band rotary joint, operating on the bands A and B (X and Ka, in a preferred embodiment) made up of two transducers T1 (11) and T2 (12), each connecting two rectangular waveguides to a cylindrical waveguide supporting modes with azimuthal symmetry. The internal part of the whole rotary joint, including the two transducers (rectangular waveguide-nested waveguide) and two chokes for the bands A and B, is shown in the figure 1/6 (For the sake of clarity, the figure shows just one half of the symmetric rotary joint). In the figure said transducers T1 and T2 are labelled by Fig. 2/6 and 3/6, respectively (for the sake of clarity, the figure shows just half transducers because they are symmetric as well).

    [0014] The rectangular waveguide ports are labelled by the numbers (101) and (102), for band A, (103) and (104), for band B.

    [0015] The cylindrical part is indeed a double coaxial waveguide, made up of two concentric cylindrical waveguides, also called 'coaxial nested waveguide'.

    [0016] The internal surface of the first cylindrical shell defines a circular waveguide, where the mode TM01 can propagate, on band B (105). The external surface of the first cylindrical shell is the internal conductor of the coaxial working on band A (106), whose external conductor is given by the internal part of the second cylindrical conductor. This kind of nested waveguide has been mainly used in some double-band antenna feeds:

    [11] S. L. Johns, A. Patra Jr, "An Ultra Wideband Nested Coaxial Waveguide Feed for Reflector Antenna Applications", IEEE Antennas and Propagation Society Int. Symposium, pages 704 - 707, 1999;

    [12] M.L. Livingston, "Multifrequency Coaxial Cavity Apex Feeds", Microwave J., Vol. 22, Oct. 1979, pages 51-54;

    [13] J.C. Lee, 'Compact Broadband Rectangular to Coaxial Waveguide Junction', US Patent Nr 4558290, 1985;
    Very recently, it been used in the rotary joint developed for the antenna designed for the Bepi-Colombo mission:

    [14] J. A. Mürer, R. Harper, "High Temperature Antenna Pointing Mechanism for BepiColombo Mission", 11th European Space Mechanisms and Tribology Symposium, ESMATS 2005, 185-194;
    from which, the present patent differs just for the modal transducer designed for coupling the two rectangular waveguides to the 'nested coaxial' waveguide.



    [0017] In addition, there are two chokes restoring the electromagnetic continuity at the two cut planes of the 'nested coaxial', necessary to make rotation possible.

    [0018] In fact there are two breaks. The first (107) cuts only the external cylinder of the nested waveguide, thus producing a discontinuity only for the TEM mode propagating within the coaxial waveguide formed by the external surface of the internal cylinder and the internal surface of the external cylinder, while the electromagnetic wave propagating within the inner of the internal cylinder (105) is not affected at all. The electrical continuity takes place through the choke A (108), which, for the above reasons, has to work just on band A. The bearing mechanism permitting rotation is also installed at the level of this break. There is then a second break (109) of the internal cylinder of the 'nested' waveguide placed below the transducer working on band A (at the bottom of the figure).

    [0019] Even in this case, the electromagnetic continuity is restored on band B, through the insertion of the choke B (110), designed in such a way that no leakage occurs between the waveguides operating on band B toward the waveguides operating on band A. The transducer between circular and rectangular waveguides on band B is seen by the waveguides operating on band A as a reactive load.

    [0020] In order to make more clear the working principles, figure 4/6 shows one section of the internal part. The main parts are:

    (201) External coaxial waveguide, CXA.

    (202) Internal circular waveguide , WCB.

    (203) Wall, whose internal surface delimits the internal circular waveguide, while the external surface delimits the internal conductor of the coaxial.

    (204) Transition WRA1-CXA1 between rectangular and coaxial waveguides working on band A.

    (205) Transition WRB1-WCB1 between rectangular and circular waveguide B.

    (206) Gap between the two circular waveguides WC1 and WC2.

    (207) Choke for the circular waveguide WCB.

    (208) Gap between the coaxial waveguides CX1 and CX2, including the choke.



    [0021] More in detail, with reference to the two bands X and Ka, the transducer is formed by two distinct transitions:

    the transition operating on Ka band, uses a circular waveguide fed in such a way that only the TM01 mode is excited. Such a transition is similar to the one proposed in [1] D.G. de Mesquita, A.G. Bailey, "A Symmetrically Excited Microwave Rotary Joint" IEEE Trans. Microwave Theory and Tech., vol. 18, No. 09, pages 654-656, Sep. 1970.



    [0022] Half of the transition rectangular waveguide (WR28) - circular waveguide (WC) (H-plane section) is shown in Fig. 5/6. The symmetry of the transition is chosen in such a way that in the planes y=0 and x=0 there are two magnetic walls, which prevent the excitation of the lower order modes TE11, H and V. The signal entering the port (301) is split into two identical parts through the bifurcation in the H. The step (302) and the septum (303) are used for matching. There is a further matching step (304) used to compensate the mismatching due to the transition rectangular - circular waveguide (305). Radius of the Ka-band circular waveguide is chosen in such a way that TM01 is above cut-off.

    [0023] The transition on X band between rectangular-coaxial waveguide employs a coaxial waveguide, whose internal conductor is just the external surface of the circular waveguide (of radius Ri) used on Ka band. The diameter of the internal conductor is therefore 2Ri + 2*t, t being the thickness of the WC wall. In practice, for mechanical reasons, it is difficult to obtain values thinner than 0.8 mm.. The internal diameter of the external conductor is chosen in such a way that the coaxial waveguide operates under monomodal propagation, or, when the electric field is too strong, such a diameter can be increased up to a limit where the TM01 mode is below cut-off. In such a case the X-band transition must have the same symmetry of the Ka-band transition in such a way that modes TE11 V and H are not excited, thus guaranteeing the independence of the response with respect to the rotation.

    [0024] The transition between coaxial and rectangular waveguide on band A appears as shown in Fig. 6/6.

    [0025] The signal incoming in port (401) is split into two identical parts through the bifurcation in the H plane. The steps (402) and the septum (403) are used for matching. There is a further matching step (404), used to compensate the mismatch generated by the transition between coaxial waveguide rectangular waveguide (405).

    [0026] The main advantages of the proposed solution with respect to the more traditional ones, are:
    1. 1) High isolation between channels, due to the physical separation between the two cylindrical waveguides.
    2. 2) Higher peak power handling capability with respect to coaxial solution, because the nested section has not to be reduced to operate at higher frequency.
    3. 3) The two chokes are designed and operate independently from each other, thus guaranteeing an accurate control of the isolation.
    4. 4) The WOW is intrinsically negligible, because in the cylindrical part only azimuthal independent modes are excited.
    5. 5) Easy manufacturing.


    [0027] Materials and dimensions of the above-described invention, illustrated in the accompanying drawings and later claimed, may be varied according to requirements. Moreover, all the details may be replaced by other technically equivalent ones without, for this reason, straying from the protective scope of the present invention patent application.


    Claims

    1. Power dual-band rotary joint simultaneously operating on two frequency bands (1), characterized by the fact of comprising at least the following components:

    a) a first transducer T1 (11) connecting two rectangular waveguides WRA1 and WRB1 operating on the bands A and B, respectively, the midband frequency of A being lower than the midband frequency of B, to a nested coaxial waveguide WN1 (23) made up of two concentric pipes, having internal radii RA and RB and whose internal wall thickness being TB,

    b) a second transducer T2 (12) connecting two rectangular waveguides WRA2 and WRB2 operating on bands A and B, respectively (the midband frequency of A being lower than the midband frequency of B) to a nested coaxial waveguide WN2 (33) made up of two concentric pipes, having internal radii RA and RB and whose internal wall thickness being TB,
    said two transducers (11) and (12) being connected through the two nested waveguides WN1 and WN2, in such a way that the aforementioned internal pipes are separated by a small gap while the two external pipes are connected through a bearing, making this arrangement possible the rotation of a transducer with respect to the other one, without affecting the electrical characteristics of the rotary joint,
    the waveguides forming the transducer T1 (11) being arranged in the order WRB1-WRA1-WN1 (21)-(22)-(23), in such a way that the more internal pipe, TUB1 (24), defining the waveguide WCB1, passes though WRA1, without any interruption or discontinuities,
    the waveguides forming the transducer T2 (12) being arranged in the order WRB2-WRA2-WN2 (31)-(32)-(33), in such a way that the internal pipe defining the waveguide WCB2 (34), passes though WRA2, without any interruption or discontinuities,

    c) a first choke (108), permitting the restoring of the electromagnetic continuity on band A in the coaxial waveguide bounded by the external surface of the internal pipe and the internal surface of the external pipe, forming the nested waveguide,

    d) a second choke (109), permitting the restoring of the electromagnetic continuity on band B in the circular waveguide bounded by the internal surface of the internal pipe and able to provide a large isolation between the parts working on band A and B.


     
    2. Power dual-band rotary joint simultaneously operating on two frequency bands (1), as defined in claim 1, characterized by the fact that:

    i) said transducer T1 (11), providing the coupling between waveguides WRA1 and CXA 1, on the one hand, and WRB1 and WCB1, on the other, has a symmetry which makes possible the excitation of the TM01 mode in WCB1, on band B, while lower order modes TE11V and TE11H, though above cut-off, are not excited at all,

    ii) The symmetry of said transducer T1 (11), makes possible the excitation of only TEM mode in the waveguide CXA1, on band A, although other higher order not symmetrical modes can be above cut-off, on band A,

    iii)one end of the internal pipe of said nested waveguide WN1 (23) is
    welded to the broad wall of WRB1 in such a way that the portion of the wall of WRB1 bounded by the intersection with the internal pipe of WN1 is removed in order to create a circular aperture through which energy flows from WRB1 to WCB1 (25), on band B,

    iv) one end of the external pipe of said nested waveguide WN1 (23) is welded to the broad wall of WRA1 in such a way that the portion of the wall of WRA1 in between the two concentric pipes of WN1 is removed to create an annular aperture through which energy flows from WRA1 to CXA1 (26), on band A,

    v) said transducer T2 (12), providing the coupling between waveguides WRA2 and CXA2, on the one hand, and WRB2 and WCB2, on the other, has a symmetry which makes possible the excitation of the TM01 mode in WCB2 on band B, while lower order modes TE11V and TE11H, though above cut-off, are not excited at all,

    vi) the symmetry of said transducer T2 (12), providing the coupling between waveguides WRA2 and CXA2, on the one hand, and WRB2 and WCB2, on the other, makes possible the excitation of only TEM mode in the waveguide CXA2, on band A, although other higher order non symmetrical modes can be above cut-off, on band A,

    vii) one end of the internal pipe of said nested waveguide WN2 (33) is welded to the broad wall of WRB2 in such a way that the portion of the wall of WRB2 bounded by the intersection with the internal pipe of WN2, is removed in order to create a circular aperture through which energy flows from WRB2 to WCB2 (35), on band B,

    viii) one end of the external pipe of said nested waveguide WN2 (33) is welded to the broad wall of WRA2, while the internal pipe passes through WRA2 undisturbed, in such a way that the portion of the wall of WRA2 in between the two concentric pipes of WN2 is removed to create an annular aperture through which energy flows from WRA2 to CXA2 (36), on band A,

    ix)just below WRA2, in the space between the broad wall of WRA2 and
    WRB2, the internal pipe is cut into two parts, TUB2_INF (35) and TUB2_SUP (34), separated by a gap, in such a way that the lateral surface of the lower part, TUB2_INF (35), intersects the broad wall of WRB2, thus making the aperture through which energy flows from WRB2 to WCB2, while the higher part, TUB2_SUP is actually the continuation of the pipe TUB1, extending, without any discontinuity (105), from the broad wall of WRB1, passing through WRA2, to the break separating from the end of TUB2_INF,

    x) electromagnetic continuity at the break of the internal pipe is restored through a choke (109), built by thickening the two juxtaposed collars which the two pipes TUB2_INF (35) and TUB2_SUP (34) end on, the aforementioned choke (109) also producing the high isolation required between signals on A and B bands, necessary to prevent the leakage of the signal on band B to the waveguides operating on band A.


     


    Ansprüche

    1. Dualband-Drehverbindung mit Betrieb auf zwei verschiedenen Frequenzbändern (1), dadurch gekennzeichnet, dass mindestens folgende Komponenten enthalten sind:

    a) ein erster Wandler T1 (11) für den Anschluss zweier Rechteckhohlleiter WRA1 und WRB1 zum Betrieb in den Bändern A und B, wobei die Bandmittenfrequenz von A niedriger als die Bandmittenfrequenz von B ist, an einen geschachtelten Koaxial-Hohlleiter WN1 (23), bestehend aus zwei konzentrisch angeordneten Rohren mit den Innenradien RA und RB und einer internen Wandstärke von TB,

    b) ein zweiter Wandler T2 (12) für den Anschluss zweier Rechteckhohlleiter WRA2 und WRB2 zum Betrieb in den Bändern A und B, wobei die Bandmittenfrequenz von A niedriger als die Bandmittenfrequenz von B ist, an einen geschachtelten Koaxial-Hohlleiter WN2 (33), bestehend aus zwei konzentrisch angeordneten Rohren mit den Innenradien RA und RB und einer internen Wandstärke von TB,
    wobei die beiden Wandler (11) und (12) durch die beiden geschachtelten Hohlleiter WN1 und WN2 so verbunden sind, dass die vorgenannten Innenrohre durch einen kleinen Zwischenraum voneinander getrennt sind, während die beiden Außenrohre durch ein Lager miteinander verbunden sind, was durch die Drehung des einen Wandlers mit Bezug auf den anderen ermöglicht wird, ohne dass dabei die elektrischen Eigenschaften der Drehverbindung beeinflusst werden, wobei weiterhin die den Wandler T1 (11) bildenden Hohlleiter sich in der Anordnung WRB1-WRA1-WN1 (21)-(22)-(23) befinden, dergestalt dass das den Hohlleiter WCB1 begrenzende innerste Rohr, TUB1 (24), ohne Unterbrechungen oder Unstetigkeiten durch WRA1 verläuft,
    wobei weiterhin die den Wandler T2 (12) bildenden Hohlleiter sich in der Anordnung WRB2-WRA2-WN2 (31)-(32)-(33) befinden, dergestalt dass das den Hohlleiter WCB2 (34) begrenzende Innenrohr ohne Unterbrechungen oder Unstetigkeiten durch WRA2 verläuft,

    c) eine erste Drossel (108) zur Wiederherstellung der elektromagnetischen Kontinuität auf Band A im Koaxial-Hohlleiter, begrenzt durch die Außenfläche des Innenrohrs und die Innenfläche des Außenrohrs, welche den geschachtelten Hohlleiter bilden,

    d) eine zweite Drossel (109) zur Wiederherstellung der elektromagnetischen Kontinuität auf Band B im Rundhohlleiter, begrenzt durch die Innenfläche des Innenrohrs und mit der Fähigkeit, eine hohe Isolation zwischen den auf Band A und Band B arbeitenden Teilen zu gewährleisten.


     
    2. Dualband-Drehverbindung mit Betrieb auf zwei verschiedenen Frequenzbändern (1) gemäß Anspruch 1, dadurch gekennzeichnet, dass:

    i) der Wandler T1 (11), welcher die Verbindung zwischen den Hohlleitern WRA1 und CXA1 einerseits und WRB1 und WCB1 andererseits darstellt, eine Symmetrie aufweist, welche die Erregung des TM01-Betriebsmodus in WCB1 auf Band B ermöglicht, während bei den unteren Betriebsmodi TE11V und TE11H, obgleich diese sich oberhalb der Abschaltschwelle befinden, keine Erregung erfolgt,

    ii) die Symmetrie des Wandlers T1 (11) die ausschließliche Erregung des TEM-Betriebsmodus in Hohlleiter CXA1 auf Band A ermöglicht, obgleich sonstige höhere, nicht symmetrische Modi auf Band A sich oberhalb der Abschaltschwelle befinden können,

    iii) ein Ende des Innenrohrs des geschachtelten Hohlleiters WN1 (23) mit der breiten Wand von WRB1 so verschweißt ist, dass der vom Schnittpunkt mit dem Innenrohr von WN1 begrenzte Teil der Wand von WRB1 entfernt wird und eine kreisförmige Öffnung entsteht, durch welche ein Energiefluss von WRB1 zu WCB1 (25) auf Band B erfolgt,

    iv) ein Ende des Außenrohrs des geschachtelten Hohlleiters WN1 (23) mit der breiten Wand von WRA1 so verschweißt ist, dass der zwischen beiden konzentrisch angeordneten Rohren von WN1 befindliche Teil der Wand von WRA1 entfernt wird und eine ringförmige Öffnung entsteht, durch welche ein Energiefluss von WRA1 zu CXA1 (26) auf Band A erfolgt,

    v) der Wandler T2 (12), welcher die Verbindung zwischen den Hohlleitern WRA2 und CXA2 einerseits und WRB2 und WCB2 andererseits darstellt, eine Symmetrie aufweist, welche die Erregung des TM01-Betriebsmodus in WCB2 auf Band B ermöglicht, während bei den unteren Betriebsmodi TE11V und TE11H, obgleich diese sich oberhalb der Abschaltschwelle befinden, keine Erregung erfolgt,

    vi) die Symmetrie des Wandlers T2 (12), welcher die Verbindung zwischen den Hohlleitern WRA2 und CXA2 einerseits und WRB2 und WCB2 andererseits darstellt, die ausschließliche Erregung des TEM-Betriebsmodus in Hohlleiter CXA2 auf Band A ermöglicht, obgleich sonstige höhere, nicht symmetrische Modi auf Band A sich oberhalb der Abschaltschwelle befinden können,

    vii) ein Ende des Innenrohrs des geschachtelten Hohlleiters WN2 (33) mit der breiten Wand von WRB2 so verschweißt ist, dass der vom Schnittpunkt mit dem Innenrohr von WN2 begrenzte Teil der Wand von WRB2 entfernt wird und eine kreisförmige Öffnung entsteht, durch welche ein Energiefluss von WRB2 zu WCB2 (35) auf Band B erfolgt,

    viii) ein Ende des Außenrohrs des geschachtelten Hohlleiters WN2 (33) mit der breiten Wand von WRA2 verschweißt ist, während das Innenrohr ungehindert durch WRA2 verläuft, sodass der zwischen beiden konzentrisch angeordneten Rohren von WN2 befindliche Teil der Wand von WRA2 entfernt wird und eine ringförmige Öffnung entsteht, durch welche ein Energiefluss von WRA2 zu CXA2 (36) auf Band A erfolgt,

    ix) leicht unterhalb von WRA2, in dem Raum zwischen der breiten Wand von WRA2 und WRB2, das Innenrohr in zwei Teile TUB2_INF (35) und TUB2_SUP (34) geschnitten wird, durch einen Zwischenraum so voneinander getrennt, dass die Seitenfläche des unteren Teils, TUB2_INF (35), die breite Wand von WRB2 durchschneidet und so die Öffnung bildet, durch welche der Energiefluss von WRB2 zu WCB2 erfolgt, während der höhere Teil, TUB2_SUP, effektiv die Fortsetzung des Rohrs TUB1 darstellt und ohne jede Unterbrechung (105) von der breiten Wand von WRB1 durch WRA2 bis zur Bruchstelle vor dem Endstück von TUB2_INF verläuft.

    x) die elektromagnetische Kontinuität an der Bruchstelle des Innenrohrs durch eine Drossel (109) wiederhergestellt wird, welche durch eine Verdickung der beiden gegenüberliegenden Manschetten am Ende der Rohre TUB2_INF (35) und TUB2_SUP (34), wobei die Drossel (109) ebenfalls die hohe Isolation zwischen den Signalen auf den Bändern A und B erzeugt, die zur Verhinderung von Leckverlusten des Signals auf Band B an die auf Band A arbeitenden Hohlleiter erforderlich ist.


     


    Revendications

    1. Joint électrique rotatif bibande fonctionnant simultanément sur deux bandes de fréquence différentes (1), caractérisé par le fait qu'il comprend au moins les composants suivants:

    a) un premier transducteur T1 (11) reliant deux guides d'ondes rectangulaires WRA1 et WRB1 opérant sur les bandes A et B, respectivement, la fréquence centrale de A étant inférieure à la fréquence centrale de B, à un guide d'onde coaxial imbriqué WN1 (23) constitué de deux tubes concentriques, ayant les rayons internes RA et RB et dont l'épaisseur de paroi interne est TB,

    b) un deuxième transducteur T2 (12) reliant deux guides d'ondes rectangulaires WRA2 et WRB2 opérant sur les bandes A et B, respectivement (la fréquence centrale de A étant inférieure à la fréquence centrale de B) à un guide d'onde coaxial imbriqué WN2 (33) constitué de deux tubes concentriques, ayant les rayons internes RA et RB et dont l'épaisseur de paroi interne est TB,
    lesdits deux transducteurs (11) et (12) étant reliés par l'intermédiaire des deux guides d'ondes imbriqués WN1 et WN2, d'une manière qui fait que les tubes internes précités soient séparés par un petit espace alors que les deux tubes externes sont connectés par l'intermédiaire d'un palier, cet agencement faisant en sorte que la rotation d'un transducteur par rapport à l'autre soit possible, sans affecter les caractéristiques électriques du joint rotatif,
    les guides d'ondes constituant le transducteur T1 (11) étant disposés dans l'ordre WRB1-WRA1-WN1 (21)-(22)-(23), d'une manière qui fait que le tube plus interne, TUB1 (24), définissant le guide d'ondes WCB1, passe à travers WRA1, sans aucune interruption ou discontinuité,
    les guides d'ondes constituant le transducteur T2 (12) étant disposés dans l'ordre WRB2-WRA2-WN2 (31)-(32)-(33), d'une manière qui fait que le tube interne, définissant le guide d'ondes WCB2 (34), passe à travers WRA2, sans aucune interruption ou discontinuité,

    c) un premier piège (108), permettant le rétablissement de la continuité électromagnétique sur la bande A dans le guide d'onde coaxial délimité par la surface externe du tube interne et la surface interne du tube externe, formant le guide d'ondes imbriqué,

    d) un second piège (109), permettant le rétablissement de la continuité électromagnétique sur la bande B dans le guide d'ondes circulaire délimité par la surface interne du tube interne et capable de fournir une isolation forte entre les pièces travaillant sur les bandes A et B.


     
    2. Joint électrique rotatif bibande fonctionnant simultanément sur deux bandes de fréquence différentes (1), comme défini à la revendication 1, caractérisé par le fait que:

    i) ledit transducteur T1 (11), réalisant le couplage entre les guides d'ondes WRA1 et CXA1, d'une part, et WRB1 et WCB1, d'autre part, présente une symétrie qui rend possible l'excitation du mode TM01 en WCB1, sur la bande B, alors que les modes d'ordre inférieur TE11V et TE11H, bien que supérieurs à la fréquence de coupure, ne sont pas du tout excités,

    ii) la symétrie dudit transducteur T1 (11), rend possible l'excitation uniquement du mode TEM dans le guide d'onde CXA1, sur la bande A, alors que les autres modes d'ordre supérieur non symétriques peuvent être supérieurs à la fréquence de coupure, sur la bande A,

    iii) une extrémité du tube interne dudit guide d'ondes imbriqué WN1 (23) est soudée à la paroi large de WRB1 d'une manière qui fait que la partie de la paroi de WRB1 délimitée par l'intersection avec le tube interne de WN1 soit retirée pour créer une ouverture circulaire à travers laquelle l'énergie peut s'écouler de WRB1 vers WCB1 (25), sur la bande B,

    iv) une extrémité du tube externe dudit guide d'onde imbriqué WN1 (23) est soudée à la paroi large de WRA1 d'une manière qui fait que la partie de la paroi de WRA1 entre les deux tubes concentriques de WN1 soit enlevée pour créer une ouverture annulaire à travers laquelle l'énergie s'écoule de WRA1 vers CXA1 (26), sur la bande A,

    v) ledit transducteur T2 (12), réalisant le couplage entre les guides d'ondes WRA2 et CXA2, d'une part, et WRB2 et WCB2, d'autre part, présente une symétrie qui rend possible l'excitation du mode TM01 en WCB2, sur la bande B, alors que les modes d'ordre inférieur TE11V et TE11H, bien que supérieurs à la fréquence de coupure, ne sont pas du tout excités,

    vi) la symétrie dudit transducteur T2 (12), réalisant le couplage entre les guides d'ondes WRA2 et CXA2, d'une part, et WRB2 et WCB2, d'autre part, rend possible l'excitation uniquement du mode TEM dans le guide d'onde CXA2, sur la bande A, alors que les autres modes d'ordre supérieur non symétriques peuvent être supérieurs à la fréquence de coupure, sur la bande A,

    vii) une extrémité du tube interne dudit guide d'ondes imbriqué WN2 (33) est soudée à la paroi large de WRB2 d'une manière qui fait que la partie de la paroi de WRB2 délimitée par l'intersection avec le tube interne de WN2 est retirée pour créer une ouverture circulaire à travers laquelle l'énergie s'écoule de WRB2 vers WCB2 (35), sur la bande B,

    viii) une extrémité du tube externe dudit tube du guide d'ondes imbriqué WN2 (33) est soudée à la paroi large de WRA2, alors que le tube interne passe sans encombre à travers WRA2, de manière à ce que la portion de la paroi de WRA2 entre les deux tubes concentriques de WN2 est enlevé pour créer une ouverture annulaire à travers laquelle l'énergie s'écoule de WRA2 à CXA2 (36), sur la bande A,

    ix) juste en dessous de WRA2, dans l'espace compris entre la paroi large de WRA2 et WRB2, le tube interne est coupé en deux parties, TUB2_INF (35) et TUB2_SUP (34), séparés par un espace, d'une manière qui fait que la surface latérale de la partie inférieure, TUB2 INF (35), croise la paroi large de WRB2, ce qui crée l'ouverture à travers laquelle l'énergie s'écoule de WRB2 vers WCB2, alors que la partie supérieure, TUB2_SUP est en fait la continuation du tube TUB1, s'étendant, sans discontinuité (105), de la paroi large de WRB1, en passant à travers WRA2, à l'interruption séparant de la fin de TUB2_INF,

    x) la continuité électromagnétique à l'interruption du tube interne est rétablie par un piège (109), créé par l'épaississement des deux colliers juxtaposés qui terminent les deux tubes TUB2_INF (35) et TUB2_SUP (34), le piège susmentionné (109) produisant également l'isolation forte requise entre les signaux sur les bandes A et B, nécessaire pour empêcher la fuite du signal sur la bande B vers les guides d'ondes opérant sur la bande A.


     




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    Cited references

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