WO1999049534A1

WO1999049534A1 - Device for coupling/decoupling signals of same amplitudes and phases

Info

Publication number: WO1999049534A1
Application number: PCT/FR1999/000649
Authority: WO
Inventors: François Ursenbach; Pascal Barrois
Original assignee: Thomson-Csf
Priority date: 1998-03-20
Filing date: 1999-03-19
Publication date: 1999-09-30
Also published as: FR2776423A1

Abstract

The invention concerns energy coupling/decoupling devices, for signals of same amplitudes and phases, usable in metric and decimetric waves. Said device comprises, series-mounted, first 3dB couplers (M1-Mn), two distribution panel boxes (B1, B2) and a second 3dB coupler (Cr). To produce a compact assembly the distribution panel boxes used have mutually parallel first and second surfaces joined together at their periphery by a ring wherein the inputs are arranged according to a radiate symmetry, and an output located in their first surface centre; the boxes (B1, B2) are arranged with their second surface opposite each other; the first couplers (M1, Mn) are mounted astride between the inputs of the two boxes. The invention is particularly applicable in transmitters operating in microwaves.

Description

COUPLING / DECOUPLING DEVICE FOR SIGNALS OF SAME AMPLITUDES AND PHASES

The subject of the invention is a device for coupling / decoupling energy for signals of the same amplitudes and phases, usable in VHF and UHF.

In what follows and in the claims, the energy coupling / decoupling devices will, to simplify the description, be studied during operations as summers of the energies delivered by several sources of the same amplitudes and phases, that is to say during of coupling operations. Of course, due to the reversibility of the electromagnetic waves, these devices can operate in both directions and therefore in decoupling to, from an energy source, supply several signals, these signals having the same amplitude and the same phase .

These devices are used, for example in microwave transmitters, to sum the elementary powers delivered by transistorized modules whose output power is limited, and thus obtain the desired power at the output of the transmitter.

Various coupling / decoupling devices exist. The most efficient of them seems to be the one described in French patent 2,625,053 and in its correspondent in the USA, patent 5,194,835. This known device comprises N couplers at 3dB at 90 °, which respectively receive the N summing signals; these couplers distribute the received signal, at equal amplitude and with an aperiodic phase shift of 90 ° to two distribution boxes; distribution boxes add up the signals they receive; an output coupler combines the output signals from the two boxes and provides an output signal which, to the nearest loss, is the sum of the input signals.

In its known embodiments, this coupling device occupies a volume which it would be desirable to reduce in many applications. the purpose of the present invention is to provide a device of the kind which has just been discussed above, but in a compact embodiment. This is obtained, in particular, thanks to the choice which is made for the distribution boxes and thanks to a suitable positioning of the distribution boxes and couplers at 3dB at 90 °.

According to the invention, a coupling / decoupling device for signals of the same amplitudes and phases is proposed for this, as described in claim 1 of this document.

The present invention will be better understood and other characteristics will appear with the aid of the description below and of the figures relating thereto which represent: FIG. 1, an electrical diagram of a coupling / decoupling device,

FIG. 2, an electrical diagram of an element of a variant of the device according to FIG. 1,

FIG. 3, a schematic view of a coupling / decoupling device according to the invention,

FIGS. 4 and 5, partial, complementary views of the element whose electrical diagram is given in FIG. 2,

- Figures 6a, 6b, partial sectional views of a coupling / decoupling device - Figure 7, a simplified view of another coupling / decoupling device.

In the various figures, the corresponding elements are designated by the same references.

In the description which follows as well as in the claims, it is a question of couplers of the type 3dB hybrid junctions, at 90 °, comprising two pairs of conjugate accesses. By pair of conjugate coupler accesses, we mean two of the four coupler ports such that, if suitable loads are connected to it, there is practically no coupling between the other two coupler ports, the other two ports also constituting a pair of conjugate accesses; and, always when suitable loads are connected to one of the pairs of conjugate accesses, the power applied to one of the two conjugate accesses of the other pair comes out through the accesses of the pair to which adapted loads are connected , at equal power but with quadrature waves of phase. On the diagrams the conjugate access pairs of couplers to 3dB, at 90 °, will be marked 1-2 and 3-4 respectively; these couplers can, without departing from the scope of the invention, be constituted by any other circuits equivalent to hybrid junctions at 3dB, at 90 °, such as, for example, magic tees or hybrid rings associated with phase shift elements of decent value.

Figure 1 is an electrical diagram of a coupling / decoupling device according to the known art and according to the invention. It is a device making it possible, for example, to feed an antenna connected to its output S, using n amplifiers of the same amplitudes and the same phases connected respectively to its n inputs E1 to En; the antenna, not shown, is supplied with the sum, to the nearest losses, of the energies supplied by the n amplifiers, not shown.

The n inputs are respectively connected to the ports 1 of n input couplers, to 3dB, A1 to An. Between the ports 2 of the couplers A1 to An, and ground, are mounted balancing resistors R1 to Rn, which constitute appropriate charges. The ports 3 of the couplers A1 to An are respectively connected to the inputs 1 to n of a distribution box B1, with n inputs and one output; similarly, the accesses 4 of the couplers A1 to An are respectively connected to the inputs 1 to n of a distribution box B2, with n inputs and an output. The outputs of distribution boxes B1, B2 are respectively connected to accesses 1 and 2 of an output coupler, at 3dB, C, whose access 3 is connected to ground by a balancing resistor Rc and whose access 4 constitutes the output S of the coupling / decoupling device. It should be noted that it is preferable to produce the output coupler using the same technology as the input couplers in order to compensate for the defects of the input couplers, in particular as regards the variation of the couplings as a function of the frequency. .

In a variant of the device according to FIG. 1, each input coupler is replaced, as shown in FIG. 2, by two couplers mounted in parallel; that is to say that, for example, the coupler to 3dB A1 is replaced by a set of two couplers to 3dB, A11 and A12, the ports 1 of which constitute two separate inputs of the device. Between the ports 2 of the couplers A1 1, A12 and the earth are mounted resistors balancing R11, R12 which constitute suitable loads. The ports 3 of the couplers A11, A12 are both connected to the same input 1 of the distribution box B1; similarly, the accesses 4 of the couplers A11, A12 are both connected to the same input 1 of the distribution box B2; thus is produced a coupling module M1. It is possible to make other variants of this coupling module, with no longer 2 but 3, or even more, 3dB couplers in parallel.

In all of these embodiments, whether with a single coupler per distribution box input or with several couplers mounted in parallel, it is essential that the paths between the different accesses 3 and 4 and the corresponding inputs of the distribution boxes B1, B2 are of identical lengths; otherwise phase shifts are introduced between the different input signals. With a single coupler per distribution box entry, this requirement on the length of the paths is easy to meet; with a coupling module with two couplers in parallel, an exemplary embodiment will be described with the aid, in particular, of FIGS. 4 and 5; for a coupling module with three couplers, mounting with the couplers at 180 ° from each other is possible without too many production problems; but the difficulties increase with the increase in the number of couplers in parallel, it being understood that it is always possible to give all the paths "coupler access-distribution box entry" identical lengths, for example by considering the paths the most direct and giving all the effective paths the length of the longest direct path.

Figure 3 is a schematic view of a device according to the invention, which shows two distribution boxes B1, B2 of the type with two parallel faces joined at their periphery by a ring, each with n inlets distributed in radial symmetry all around of this crown. The boxes B1, B2 have their outlet located at the center of radial symmetry of one of their two faces and have their two other faces opposite. All around the boxes B1, B2 are regularly distributed n coupling modules of which only three M1, M2, Mn, have been represented. These coupling modules are either made up of a single 3dB coupler with its balancing resistance and in this case n is equal to the number of input couplers, or made up of several of these "coupler- resistor "connected in parallel as described using FIG. 2 and in this case the number of input couplers is greater than the number of modules.

The couplers of the n coupling modules are mounted, straddling the two distribution boxes with their access 3 connected to an input of the box B1 and their access 4 connected to an input of the box B2, and these two inputs to which are connected the accesses of the same coupler are substantially opposite.

The outputs of the boxes B1, B2 are connected by coaxial cables to the inputs 1 and 2 of a 3dB coupler associated, in a Cr module, with a balancing resistor. This module Cr corresponds to the elements C and Rc of FIG. 1.

Figure 4 is a view of part of an exemplary embodiment of a coupling module. This example corresponds to the electrical diagram in Figure 2; the coupling module therefore comprises two couplers each with a balancing resistor.

The two couplers according to FIG. 4 are 90 ° 3dB hybrid junctions which each have four accesses numbered 1, 2, 3 4. These accesses are the ends of two pairs of coupled lines, L1-L1 ', L2-L2' ; the length of the lines is substantially equal to a quarter of the average working wavelength of the couplers; the lines of the same pair are placed opposite one another and their spacing is chosen to give the desired coupling, that is to say the coupling which corresponds to a coupler at 3dB, at 90 °. The two pairs of lines are placed side by side with short circuits between the ports 3 on the one hand and the ports 4 on the other; these accesses leave conductors marked 3 + 3 and 4 + 4, intended to connect the coupling module respectively to boxes B1 and B2.

Two coaxial cables terminate, by their internal conductors, referenced E11, E12 respectively on the access 1 relating to the pair L1-L1 'and on the access 1 relating to the pair L2-L2'.

Resistors R11, R12 are connected at one of their ends respectively to the ports 2 of the pairs of lines L1-L1 'and L2-L2'.

FIG. 4 shows one of the parts of a coupling module, the other part of which is shown in FIG. 5. This other part comprises a kind of large hollow bar, D, with on one side a parallelepipedic protuberance, Da, and, on the other side, two hollow tubes Db, De.

The bar D is pierced with two parallel cylindrical holes D1, D2 connected together, towards each of the ends of the bar, by a transverse hole; one of these transverse holes, referenced D4, appears in FIG. 5.

The hollow tubes Db, De are mutually parallel and perpendicular to the bar D; their internal holes, respectively referenced D33 and D44, open respectively in the two transverse holes; in FIG. 5, the junction between the hole D44 and the transverse hole D4 is partially visible.

The protrusion Da is located substantially on the other side of the bar D relative to the tube De; this protuberance Da comprises a pipe, not shown, with an inlet, a circulation and a departure of refrigerated liquid. On either side of the protrusion Da two square section holes are drilled in the bar D and these holes open respectively in the cylindrical holes D1, D2; that of these holes which opens into the hole D2 is visible in FIG. 5 and is referenced D6.

The two parts shown respectively in FIGS. 4 and 5 of a coupling module are assembled with:

- the pairs of lines L1-L1 ', L2-L2' respectively inside the holes D1, D2,

- conductors 3 + 3 and 4 + 4 respectively in holes D33 and D44,

- Resistors R11, R12 respectively plated on two opposite faces of the protrusion Da; the position of the resistor R12 on the protrusion Da has been identified, in FIG. 5, by a rectangle drawn in dotted lines; this positioning of the resistors on the protrusion Da is intended to allow good dissipation of the calories produced in these resistors. The positioning of the various elements of FIG. 4 relative to those of FIG. 5 is ensured by shims made of dielectric material, apart from the resistors R11, R12 which are each mounted in a housing and this housing is held against the 'protuberance Da, using two screws not shown. The assembly of the elements of the figure 4 can be achieved in two ways: either by assembling piece by piece the different constituents in and on the assembly according to FIG. 5, or by carrying out the assembly as indicated in FIG. 4 but using a bar D, in two parts, separated by a plane passing through the longitudinal axes of symmetry of the cylindrical holes D1, D2; the trace, T, of this section plane is drawn in FIG. 5; for this second possibility of embodiment, the assembly according to FIG. 4 is placed in the part of the bar D from which the tubes Db start, From then the two parts of the bar are assembled by welding. FIGS. 6a, 6b are two partial views, in diagrammatic section, of the same coupling / decoupling device during assembly, at the moment when a first coupling module, M1, of the kind which is described using Figures 2, 4, 5, is connected to one of the inputs of one, B1, of the two distribution boxes. It is a distribution box of the kind described with the aid of Figures 1 and 3, with, here, n = 6 and a hexagonal periphery. Examples of embodiment of distribution boxes are described in French patent 2,628,894 and in its correspondent in the USA, patent 4,933,651.

The section plane of Figure 6a passes through the longitudinal axis, not shown, of a coaxial cable Bs1 which constitutes the outlet of the box B1, outlet which has already been discussed in the description of Figure 3. The cutting plane also passes through the longitudinal axis, not shown, of a 3 + 3 conductor which is the counterpart of the 3 + 3 conductor according to FIG. , otherwise it would appear that the section plane also passes through the longitudinal axis, not shown, of a conductor which is the counterpart of conductor 4 + 4 according to FIG. 4.

FIG. 6a shows a cable with its internal conductor E1 1, seen by transparency, as well as a pair of lines L1-L1 ', also seen by transparency; these elements are the pendants of the elements of Figure 4 which bear the same references.

A metal cover K1 completes the coupling module M1. The section plane of FIG. 6b passes through the longitudinal axes, not shown, of the conductors such as 3 + 3 of the six coupling modules, such as M1, to be connected to the distribution box B1.

In FIG. 6b appear, the cover K1 and the elements L1-L1 ', L2-L2', 3 + 3, Re1, Re2 which are the pendants of the elements which bear the same references in FIG. 4.

It should be noted that the coaxial cables which terminate on the accesses of the two 3dB couplers that the coupling module M1 comprises, have a characteristic impedance of 50 ohms. The characteristic impedance of coaxial cables such as that whose internal conductor has the reference 3 + 3 is therefore 50/2 = 25 ohms and the impedance reduced to the center of the distribution box B1, when coupling modules are connected on its six inputs, is 25/6 ohms. To find a characteristic impedance of 50 ohms when the coaxial cable Bs1 which leaves from the output of the distribution box B1, terminates on the module Cr according to FIG. 3, it is necessary to provide for an impedance transformation; in the example described, as it appears in FIG. 6a, this is achieved with an output cable Bs1 whose cross section of the internal conductor varies to form quarter wave transformers. Impedance transformations on the conductors such as 3 + 3 and the conductors which extend them in the distribution boxes are also possible to find a characteristic impedance of 50 ohms.

Figure 7 is a schematic view from above, corresponding to the sectional views according to Figures 6a, 6b but in an alternative embodiment using distribution boxes with 26 inputs and 26 coupling modules which, here too, are with two couplers in parallel. On this view have been drawn: - one, B1, distribution boxes; the other does not appear because it is just below box B1 - five, M1, M13, M14, M20, M26, of the 26 coupling modules - the output cables Bs1 and Bs2 of the two distribution boxes - one Cr module comprising a 3dB coupler associated with a balancing resistor.

The present invention is not limited to the examples described. Thus, in particular, a circulation of refrigerated liquid can be carried out inside the internal conductor of each of the two coaxial cables, such as Bs1, in FIG. 6a, which constitute the outputs of the distribution boxes. For this, the liquid inlet and outlet can be arranged on the face of the box which is opposite to the face from which the coaxial outlet cable leaves: - a hole is drilled, at this point, in the wall of the box - a first hollow metal tube coming from outside the box ends on the periphery of this hole - two tubes, one for the arrival the other for the departure of the liquid, are arranged in the hollow tube - and a quarter wave trap which brings an infinite impedance to the level of the hole is obtained by means of a short circuit placed between the first tube and the two tubes it contains, at a distance from the hole equal to a quarter of the length of mean working wave of the coupling / decoupling device.

Claims

10 CLAIMS

1. Coupling / decoupling device for signals of the same amplitudes and phases, comprising n + 1 coupling modules (M 1 -Mn, Cr) including n input modules (M 1 -Mn) for receiving the signals and an output module ( Cr) and a first (B1) and a second (B2) distribution box with each of the inputs connected to the n input modules and an output connected to the output module, characterized in that the distribution boxes (B1, B2) are of the type with two parallel faces joined at their periphery by a ring in which the inlets (1 -n) are distributed in a radial symmetry, and in an outlet located in the center of radial symmetry of one of their two faces, in that that the boxes have their two other faces opposite and in that the n input modules (M 1 -Mn) are distributed around the crowns, each straddling an entry of the first box (B1) and an entry from the second box (B2). 2. Coupling / decoupling device according to claim 1, characterized in that the input modules are constituted by the association of a 3dB coupler (A1 -An) and a balancing resistor (R1 -Rn ), the coupler having a first pair of conjugate accesses (1,

2) with a first port (1) for receiving one of the signals, a second port (2) to which the balancing resistor (R 1 -Rn) is connected, and a second pair of ports combined with a third connected port to one of the inputs of the first box (B1) and a fourth access connected to one of the inputs of the second box (B2).

3. Coupling / decoupling device according to claim 1, characterized in that each input module (M 1 -Mn) consists of k, with k integer greater than 1, couplers at 3dB (A1 1, A 1 2) respectively associated with k balancing resistors (R1 1, R1 2), each of the module couplers having a first pair of conjugate accesses (1, 2) with a first access (1) for receiving one of the signals, a second access (2) to which is connected the balancing resistor (R1 1, R1 2) with which it is associated and a second pair of conjugate accesses (3, 4) with a third (3) and a fourth (4) access , in that the third ports of the couplers of the same module are interconnected and connected to one of the inputs of the first box (B1) and in this 1 1

that the fourth ports of the couplers of the same module are interconnected and connected to one of the inputs of the second box (B2).

4. Coupling / decoupling device according to claim 3 wherein k = 2, characterized in that the two couplers of the modules (M 1 -Mn) are of the type with two coupled lines (L1, L1 '; L2, L2') and in that each module comprises a hollow metal bar (D) with two cavities in which the two couplers are disposed respectively and with openings to make the couplers communicate with each other and with the balancing resistors and make it possible to constitute accesses ( E1 1, E1 2, 3 + 3, 4 + 4) for the module.