EP0465994B1 - Microwave triplate module - Google Patents

Description

The invention relates to a three-plate microwave module.

• répartition de puissance en vue d'alimenter des éléments rayonnants ;
• circuiterie intervenant dans les étages de puissance d'un transpondeur (matrice généralisée de coupleurs, ou "Buttler array" par exemple).

Les fonctions élémentaires les plus couramment utilisées concernent

• la division de puissance : d'un bras de ligne on désire adresser des niveaux définis à différentes sous-lignes ; Ceci pouvant être obtenu à l'aide :
  • . d'un "té" (compensé ou non), qui peut comporter plus de trois branches, qui peut être équilibré ou non ;
  • . de circuits en échelle : deux, trois ou quatre branches. Là encore le dessin du composant dépend des objectifs intrinsèques requis (dynamique de division, adaptation, largeur de bande) ; De nombreux abaques existant dans la littérature sur le dimensionnement de ce type de composant ;
  • . de circuits en anneau ; Là encore une littérature importante existe ("rat-race" (souricière) ou hybride en anneau) de sorte que le dimensionnement de ce type de composant est largement maitrisé.
• le changement de plan : La propagation triplaque s'établit de façon planaire entre deux plans de masse parallèles. Il est alors nécessaire, pour des raisons d'encombrement ou d'interface, de pouvoir accéder au circuit à l'aide d'un guide d'onde ou d'une transition en mode coaxial, ou encore de pouvoir faire rayonner l'énergie distribuée par le circuit à l'aide d'un élément rayonnant. Là encore l'excitation de l'élément rayonnant peut se faire à l'aide d'une sonde coaxiale et requiert une transition triplaque coaxiale.

The propagation of electromagnetic waves in a triplate mode calls on a set of components ensuring particular functions. These components are then used in the form of assemblies in order to achieve the envisaged mission:

• power distribution in order to power radiating elements;
• circuitry involved in the power stages of a transponder (generalized matrix of couplers, or "Buttler array" for example).

The most commonly used basic functions concern

• the power division: from a line arm we want to address defined levels to different sub-lines; This can be obtained using:
  • . a "tee" (compensated or not), which can have more than three branches, which can be balanced or not;
  • . of ladder circuits: two, three or four branches. Again the design of the component depends on the intrinsic objectives required (dynamic of division, adaptation, bandwidth); Many charts exist in the literature on the dimensioning of this type of component;
  • . ring circuits; Here again, an important literature exists ("rat-race" (mousetrap) or hybrid ring) so that the dimensioning of this type of component is largely mastered.
• the change of plane: The triplate propagation is established in a planar way between two parallel planes of mass. It is therefore necessary, for reasons of space or interface, to be able to access the circuit using a waveguide or a transition in coaxial mode, or to be able to radiate energy distributed by the circuit using a radiating element. Again the excitation of the radiating element can be done using a coaxial probe and requires a coaxial triplate transition.

Thus in a work entitled "Stripline circuit design" by Harlan Howe, jr (Microwaves associates: Burlington, Mass; pages 44-49) which deals with interconnections of triplate circuits, is described such a connection which can be carried out by means of coaxial connectors in the axis of the triplate (Figure 2-14) or perpendicular thereto (Figure 2-15).

These two types of connection have the major drawback of using welds which reduce the reliability of the contacts.

• changement de plan ;
• distribution d'énergie sur un nombre déterminé de voies.

The subject of the invention is a module which makes it possible to ensure, in a single unit and without any mechanical connection, all or part of the preceding functions:

• change of plan ;
• distribution of energy over a determined number of channels.

• au moins une première ligne située dans un premier plan ;
• au moins une seconde ligne ;
• une ouverture de couplage située dans un second plan de manière à permettre une transmission entre ces deux lignes ;

ces différentes lignes étant isolées entre elles en courant continu, caractérisé en ce que ledit module comprend un ensemble de deux cavités, réalisées dans deux blocs conducteurs, implantées l'une sur l'autre et séparées entre elles à l'aide d'une pièce conductrice plane dont la circonférence associée à l'ensemble des deux rebords des deux cavités réalise la fente de couplage.To this end, it offers a triple plate microwave module, comprising

• at least a first line located in a first plane;
• at least a second line;
• a coupling opening located in a second plane so as to allow transmission between these two lines;

these different lines being isolated from each other by direct current, characterized in that said module comprises a set of two cavities, produced in two conductive blocks, located one on the other and separated from each other by means of a part planar conductor whose circumference associated with the assembly of the two edges of the two cavities makes the coupling slot.

Advantageously, the positioning of each line in one or the other cavity is carried out using spacers, each line penetrating a cavity through a window.

Advantageously, a second line is arranged in a third plane so that the coupling opening is located between the first plane and a third plane.

Such a module makes it possible to avoid any contact during a change in propagation mode, for example during a triplate-coaxial-triplate transition necessary for connecting different transmission planes.

Such a module can be used to perform division, phase shift or distribution functions in triplate mode. It allows thus to realize generalized couplers by using elementary modules all identical.

Such a module can advantageously be used at the output of a slot antenna directly driven in triplate mode.

The advantage of such a solution lies in its great simplicity (no adjustment), in its flexibility of design and topology (inputs / outputs), as well as in its general compactness.

• les figures 4 à 6 illustrent différentes variantes de réalisation du module hyperfréquence selon l'invention en vues éclatées.
• la figure 7 illustre un exemple de réalisation d'un élément du module selon l'invention ;
• la figure 8 illustre différentes courbes de fonctionnement d'un module selon l'invention.
• la figure 9 illustre une variante de réalisation du module hyperfréquence selon l'invention.

The characteristics and advantages of the invention will moreover emerge from the description which follows, by way of nonlimiting example, with reference to the appended figures in which: FIGS. 1 to 3 illustrate a first embodiment of the microwave module according to the invention, respectively in exploded view, in perspective and in section III-III of FIG. 2.

• Figures 4 to 6 illustrate different embodiments of the microwave module according to the invention in exploded views.
• FIG. 7 illustrates an exemplary embodiment of an element of the module according to the invention;
• FIG. 8 illustrates different operating curves of a module according to the invention.
• FIG. 9 illustrates an alternative embodiment of the microwave module according to the invention.

FIGS. 1, 2 and 3 represent a microwave module according to the invention which allows a change of plane between two triplate lines 10 and 11 with possibly, as shown in these figures, a change of direction between these lines 10 and 11.

The heart of this module is a set of two cavities 12 and 13 produced respectively in conductive blocks, for example metallic, 14 and 15. These cavities 12 and 13 are located one on the other and are separated from each other at using a conductive piece, for example metallic, planar 16, for example a disc, the circumference of which is associated with the assembly of two edges of the cavities 12 and 13 makes a coupling slot 17 making it possible to convey electromagnetic energy from one cavity to another. The transfer of energy therefore depends on the geometric shapes of the cavities 12 and 13 and on the coupling slot 17.

Access to a cavity 12 (or 13) is done using a triplate line 10 (or 11). The positioning of this line (10 or 11) inside the corresponding cavity is conventionally carried out at mid-height of the ground planes using spacers made of dielectric material 18 and 19 (or 20 and 21) . Each triplate line (10 or 11) enters the corresponding cavity (12 or 13) through a window (22 or 23) whose geometry is dimensioned in a manner known to those skilled in the art to ensure electrical continuity and continuity of impedance.

As shown in section in FIG. 3, the module according to the invention comprises two levels of triplate circuits; each of them being formed by two ground planes arranged on either side of a line (10, 11) which allows the transfer of energy; the central ground plane, produced by part 16, being common to the two levels. The coupling opening 17 therefore allows transmission between the two lines 10 and 11 which are isolated from each other by direct current.

• les impédances et géométries des lignes peuvent être quelconques ;
• les implantations des accès ne doivent pas nécessairement respecter des conditions de géométrie connues dans le cas d'autres types de dispositifs : coupleur en échelle ou en anneau ;
• la forme des cavités 12 et 13 n'est nullement restreinte à des cylindres circulaires mais peut très bien prendre des géométries polyédrales (cube, parrallélépipède, cylindres pentagonaux ou hexagonaux...), qui, par exemple, peuvent simplifier les usinages des fenêtres 22 ou 23 d'accès aux cavités 12 ou 13. Il peut aussi être fait état de discontinuités ou d'assymétries pour des applications particulières (encoches, dents, chanfrein etc..).

It should be noted that no restrictive condition is required for the module according to the invention to be able to fulfill its mission:

• the impedances and geometries of the lines can be arbitrary;
• the access locations do not necessarily have to comply with known geometry conditions in the case of other types of devices: ladder or ring coupler;
• the shape of the cavities 12 and 13 is by no means restricted to circular cylinders but can very well take polyhedral geometries (cube, parrallélépipède, pentagonal or hexagonal cylinders ...), which, for example, can simplify the machining of windows 22 or 23 for access to the cavities 12 or 13. It may also be reported discontinuities or asymmetries for particular applications (notches, teeth, chamfer, etc.).

In the plan change function in triplate propagation, the cavities 12 and 13 are configured as shown in FIG. 2, and the module according to the invention makes it possible to transmit electromagnetic energy, conveyed by line 10 in a first plane and according to a first direction, second line 11 located in another plane, this second line 11 being directed in another direction whose projection in the first plane makes an angle φ with the first direction.

• . Diamètre des cavités 12 et 13 ∼ 80 mm
• . Profondeur des cavités 12 et 13 ∼ 4.3 mm
• . Largeur et hauteur des fenêtres 22 et 23 ∼ 20 mm et 6.3 mm
• . Largeur des lignes 10 et 11 ∼ 9 mm
• . Epaisseur des lignes 10 et 11 ∼ 0. 3 mm
• . Diamètre approximatif du disque 16 ∼ 45 mm
• . Epaisseur du disque 16 ∼ 0.3mm

Such a module can be produced using, and this is only an example, the following geometries:

• . Diameter of cavities 12 and 13 ∼ 80 mm
• . Depth of cavities 12 and 13 ∼ 4.3 mm
• . Window width and height 22 and 23 ∼ 20 mm and 6.3 mm
• . Line width 10 and 11 ∼ 9 mm
• . Line thickness 10 and 11 ∼ 0.3 mm
• . Approximate disc diameter 16 ∼ 45 mm
• . Disc thickness 16 ∼ 0.3mm

The change of direction of propagation function in the same plane can be obtained by configuring the cavities 12 and 13 as in FIG. 4 for example. In this case the upper cavity 13 is completely closed and is filled with a spacer dielectric disc 24, for example of about 6 mm.

The bottom cavity 12, for its part, is provided with two access windows 22 and 23 ensuring the passage of the two lines 10 and 11.

Here again, on the basis of the module, the geometry of which has been given previously, it is possible, by managing the shape of the part 16, to produce a component making it possible to transmit electromagnetic energy conveyed by line 10 to line 11 located in the same plane, the latter having any orientation φ relative to the line 10 between 30 ° and 150 °; these angular limits being imposed by the geometries of the conductors 10 and 11 on the one hand, as well as by the volumes required by the access windows 22 and 23. Again negligible losses have been measured for this type of transition (≦ 0.05 dB).

In the configuration shown in Figure 5, as in the case of the previous function, the upper cavity 13 is fully closed while four access windows are made in the lower cavity 22, 23, 26 and 27. In such an embodiment electromagnetic energy carried by line 10 is distributed over lines 28 and 29, while line 11 is perfectly isolated.

As has been emphasized previously, the geometry of the part 16, associated with the shapes taken by the cavity 12, is essential. Such an architecture in fact makes it possible to carry out any power distributions:

Typically a dynamic range of 10 to 15 dB on α or β is achievable, giving the module of the invention the capacity of a directional coupler, the case of the division by two being in any event only a particular case .

• à 90° : le dispositif se comporte alors comme une jonction hybride.
• à 0° : le dispositif se comporte alors comme un "té" magique.
• à 0° : le dispositif assure une répartition de puissance demandée avec un réglage de phase intégré.

The output phases can also be subject to specific optimization. Practically by redefining the whole geometry of cavities + conductors, it is possible to exit between tracks 28 and 29:

• at 90 °: the device then behaves like a hybrid junction.
• at 0 °: the device then behaves like a magic "tee".
• at 0 °: the device provides a requested power distribution with an integrated phase adjustment.

The flexibility of realization therefore appears total, as the possibilities of the invention are important.

• . Diamètre des cavités 12 et 13 ∼ 80 mm
• . Profondeur des cavités 12 et 13 ∼ 6.3 mm
• . Largeur et hauteur des fentes 22, 23, 26 et 27 ∼ 20 mm et 6,3 mm
• . Largeur des lignes 10, 11, 28 et 29 ∼ 9 mm
• . Distances des extrémités des lignes 10, 11, 28 et 29 au centre de la cavité circulaire 12 ∼ 10 mm
• . Epaisseur de ces lignes 10, 11, 28 et 29 ∼ 0.3 mm
• . Epaisseur des diélectriques espaceurs 18 et 19 ∼ 3 mm
• . Epaisseur du diélectrique 24 ∼ 6 mm
• . Diamètre de la pièce 16 ∼ 45 mm
• . Epaisseur de la pièce 16 ∼ 0.3 mm

A concrete example using the following geometrical characteristics made it possible to achieve a 3dB hybrid configuration:

• . Diameter of cavities 12 and 13 ∼ 80 mm
• . Depth of cavities 12 and 13 ∼ 6.3 mm
• . Width and height of slots 22, 23, 26 and 27 ∼ 20 mm and 6.3 mm
• . Line width 10, 11, 28 and 29 ∼ 9 mm
• . Distance from the ends of lines 10, 11, 28 and 29 to the center of the circular cavity 12 ∼ 10 mm
• . Thickness of these lines 10, 11, 28 and 29 ∼ 0.3 mm
• . Thickness of the dielectric spacers 18 and 19 ∼ 3 mm
• . Dielectric thickness 24 ∼ 6 mm
• . Workpiece diameter 16 ∼ 45 mm
• . Workpiece thickness 16 ∼ 0.3 mm

• Adaptation sur l'un quelconque des accès 10, 11, 28 ou 29 ROS ≦ 1.20
• bande de fonctionnement :   8% 2850/3120 MHz
• Division puissance (28 ou 29) :   - 3 dB ± .05 dB
• Déphasage entre les lignes 28 et 29 :   90° ± 0,50°
• Isolation ligne 11 :   20 dB

For such a basic geometry and by optimizing the part 16, the following electrical performances are obtained:

• Adaptation on any of the accesses 10, 11, 28 or 29 ROS ≦ 1.20
• operating band: 8% 2850/3120 MHz
• Power division (28 or 29): - 3 dB ± .05 dB
• Phase shift between lines 28 and 29: 90 ° ± 0.50 °
• Line insulation 11: 20 dB

• une grande intégration des fonctions ;
• une grande compacité.

In a variant of the invention shown in FIG. 6, there is integrated on the one hand the embodiment represented in FIG. 1 as well as that represented in FIG. 5. On the basis of FIG. 5, the excitation line 10 as well that a coupled line 28 are located in the lower plane. The second coupled line 29 as well as the isolated line 11 are located on the upper plane which allows previously unimaginable circuit topologies and can be summarized by:

• a great integration of functions;
• great compactness.

In fact, we realize that these different lines can be arranged indifferently on the lower or upper floor and this without modifying the radiofrequency (RF) characteristics. All configurations are therefore possible: line 10 above or below; line 11 above or below; line 28 above or below; line 29 above or below.

The device of FIG. 5 has also been produced with eight windows: top and bottom for each access whatever the configuration of the parts. Performances in all respects similar to the configuration in FIG. 5 were measured, irreparably reflecting the versatility of the concept.

The geometry of the part 16 is essential because it determines the shape of the slot 17. It is therefore subject to careful optimization.

• . Bande de fréquences : 2630 MHz - 2970 MHz (12% centrée à 2800 MHz) ;
• . R.O.S. sur les parties 10 et 11 ≦ 1.20 sur la bande ;
• . Pertes intrinsèques de la transition ≦ .05 dB ;
• . angle φ quelconque entre 0 et 2 π ; cet angle φ choisi dimensionnant la géométrie de la pièce 16.

The following electrical performances were obtained for one of the modules described above:

• . Frequency band: 2630 MHz - 2970 MHz (12% centered at 2800 MHz);
• . ROS on parts 10 and 11 ≦ 1.20 on the tape;
• . Intrinsic losses of the transition ≦ .05 dB;
• . any angle φ between 0 and 2 π; this angle φ chosen dimensioning the geometry of the part 16.

Figure 7 gives an example of possible shape for the part 16, here the shape of a cross, using for example the first line 10 at the lower level and the other three lines 11, 28 and 29 at the upper level. But any combination of levels provides the same functionality. In the module of the invention, therefore, we play on the shape of the part 16 (disc, cross, disc provided with notches ...) to obtain the desired operation.

Using the variants of the module of the invention shown in Figures 5 and 6 it is possible to perform a hybrid function. The curves shown in FIG. 8 are then obtained which are a function of the frequency f: a differential phase curve 30 between two ports, for example lines 28 and 29, and curves 31 and 32 of power levels S of these ports compared to line 10, for example.

It is thus seen that one can obtain the same operation as that of a hybrid coplanar circuit by carrying out a change of plane without contacts.

It is therefore possible to use the module of the invention to the maximum of its possibilities in a foreground (for example power division, hybrid junction, etc.) before using its possibilities linked to such a transition between two planes.

Such a module can be attached in one piece in composite technology by cooking.

The part 16 can be produced, for example, by machining, by etching, by metallic deposit, etc.

As shown in FIG. 9, one can also consider one (or more) parts 33 similar to part 16, which make it possible to define one (or more) coupling slots 34 by proceeding by stacking several planes; which makes it possible to obtain a greater number of accesses (here additional lines 35 and 36 located between two spacer devices 37 and 38), and therefore to increase the number of access planes, the implantation density, and possibly the bandwidth.

It is understood that the present invention has only been described and shown as a preferred example and that its constituent elements can be replaced by equivalent elements without, however, departing from the scope of the invention.

Thus one can use triplate circuits suspended, for example, by rivets using air as a dielectric.

Claims (9)

1. A stripline microwave module comprising:
      at least one first line (10) situated in a first plane;
      at least one second line (11);
      at least one coupling opening (17) situated in a second plane so as to enable transmission to take place between said two lines (10, 11); the various lines (10, 11) being DC isolated from one another, the module being characterized in that it includes a set of two cavities (12, 13) made in two conductive blocks (14, 15) disposed one on the other and separated from each other by means of a conducting part (16) whose circumference co-operates with the two rims of the two cavities (14, 15) to define the coupling opening (17).
2. A module according to claim 1, characterized in that each line (10, 11) is positioned in one or other of the cavities (12, 13) by means of spacer devices (18, 19, 20, 21), with each line penetrating into a cavity through a window (22, 23).
3. A module according to claim 1 or 2, characterized in that the second line (11) is situated in the first plane.
4. A module according to claim 3, characterized in that a third line and a fourth line (28, 29) are situated in the first plane.
5. A module according to claim 1 or 2, characterized in that at least one second line (11) is disposed in a third plane such that the coupling opening is situated between the first plane and said third plane.
6. A module according to claim 5, characterized in that a third line (28) is situated in the first plane and a fourth line (29) is situated in the third plane.
7. A module according to any preceding claim, characterized in that the conductive part (16) is disk shaped.
8. A module according to any one of claims 1 to 6, characterized in that the conductive part (16) is cruciform.
9. A module according to any one of claims 1 to 8, characterized in that it includes at least one other part (33) analogous to the conductive part (16) thereby defining at least one other coupling opening (34), thus producing a stack of a plurality of planes.

Images