Unitary RF coaxial connector for card-to-card or module card with three adjacent coaxial lines of increasing diameter

Abstract

The invention relates to a unitary coaxial connector (1), intended to transmit RF radiofrequency signals, with a longitudinal axis X, comprising three coaxial lines (2, 3, 4) adjacent along the X axis, mainly devoid of solid electrical insulation, with constant nominal impedances on each coaxial line, regardless of the length of each of said coaxial lines, the nominal impedances being preferably equal and at least one of which slides into another adjacent one, and the diameters of the central and external contacts of which increase from one longitudinal end to the other of the connector, with a peripheral guide element (5) which makes it possible to guide and refocus the sliding external contact over a large length of movement.

Description

Technical field

[0001] The present invention relates to the field of electrical connection and more particularly relates to a unitary RF connector.

[0002] Such a unitary connector can be used in particular to connect two parallel printed circuit boards, usually called a board-to-board (B2B) connection or printed circuit board (PCB) to another component such as a module or a filter, usually called a board-to-filter or board-to-module.

[0003] The applications particularly targeted by the invention are the connection of telecommunication equipment such as BTS base transceiver stations, RRU / RRH (Remote Radio Unit / Remote Radio Head) units, antenna-integrated RRU / RRH solution, Telecom Massive MIMO antenna applications and distributed antennas of systems for the wireless communications market.

[0004] The invention also relates generally to connectors in the field of telecommunications, in the medical field, the industrial field, the aeronautical field, the transport field and the space field.

[0005] The connectors according to the invention can in particular be used to connect two parallel printed circuits, usually called a board-to-board connection system or printed circuit to another component such as a module, a filter or a power amplifier or an antenna, or module to module.

[0006] By "RF connector" is meant a connector capable of transmitting signals from the Direct Current (DC) range to the radio frequency (RF) range, including the microwave (HF) range, the signals being high-speed digital signals (HSDL for High Speed ​​Data Link) or radio frequency (RF) signals.

[0007] By “unitary” we mean that the connector according to the invention, once assembled, forms a single object. Prior art

[0008] With the continuous development of wireless communication technology, board-to-board connectors are increasingly used in the interconnection of wireless system modules, such as communication base stations, RRHs, repeaters, GPS devices, and other similar applications. The three main trends in wireless devices are smaller size, lower cost, easier installation, and the increasing frequency of the RF signals used. For board-to-board connections, the market also requires them to be smaller, cheaper, and more modular.

[0009] There are already examples on the market and in the prior art of connection assemblies dedicated to the telecommunications sector for cellular radiotelephony interconnections. Indeed, the trend in this market is to minimize the losses of the RF (radio frequency) part in order to reduce the amplifier components of the base stations. For this, on the one hand, the current radio part of the stations is increasingly relocated closer to the transmitting-receiving antennas, in the RRU / RRH transmitter modules, and on the other hand, the RF cables internal to the radio units are replaced by direct interconnections.

[0010] So-called card-to-card connections have thus developed over successive generations over the last decade.

[0011] There are already commercial products for making these connections, including unitary products.

[0012] Mention may be made here of the IMP series connectors in the name of the applicant, as described in patent EP1028490B1. These connectors are not suitable for all configurations, in particular due to a low axial travel and a low radial positioning tolerance. Also, the frequencies for which these connectors are intended are not high.

[0013] We can also mention the coaxial compression connectors marketed by TYCO ELECTRONICS under commercial reference 619127-1. These connectors are bulky due to their large diameter for board-to-board applications. They also have a short axial travel and a reduced operating frequency range.

[0014] Furthermore, patent US6776668B1 discloses a coaxial connector for a board-to-board connection, suitable for compensating for an angular defect between the printed boards, up to 3°. However, the connector is not suitable for providing a wide range of axial distance between the two boards.

[0015] More generally, there is a need to further improve card-to-card or card-to-module or card-to-filter connections, in particular to meet the specifications set by the inventors, namely: a connector with a very simple structure, which is made up of a minimum of spare parts, and which minimizes the environmental impact by not using hazardous substances such as per- and polyfluoroalkyl substances (PFAS), lead or beryllium; a simple structure and a low-cost connector; the possibility of using a connector reference for a wide axial positioning range between two parallel printed boards, typically + / - 1 mm or + / - 1.5 mm; the possibility of connecting two parallel printed boards, radially offset from each other, typically with a radial misalignment of + / - 0.5 mm to + / - 1 mm; a footprint, therefore an external diameter, typically less than 5 mm; an operating frequency range from direct current DC to 20 GHz.

[0016] The invention aims to meet all or part of this need. Statement of the invention

[0017] To this end, the invention relates, according to one of its aspects, to a unitary coaxial connector, intended to transmit RF radiofrequency signals, with a longitudinal axis X, comprising: three adjacent coaxial lines along the longitudinal axis X and whose diameter increases from one adjacent line to the other, from one of the longitudinal ends of the connector to the other of its longitudinal ends, each of the lines each comprising a central contact and an external contact arranged around the central contact, at least one central contact of a coaxial line being sliding in a central contact of one of the other lines adjacent to it, at least one external contact of a coaxial line being sliding in an external contact of one of the other lines adjacent to it so that the length of the intermediate coaxial line can vary, the volume between the central contact and the external contact of the intermediate line being devoid of solid electrical insulation; a guide element, preferably in the form of a hollow tube, the internal surface of which is adapted to mechanically guide at least the external contact of the coaxial line which extends from one of the longitudinal ends of the connector.

[0018] By "free of solid electrical insulator" we mean that the electrical insulator consists of air or an electrically non-conducting gas, for example nitrogen, or a vacuum.

[0019] By "solidary" we mean fixed or carried out entirely with.

[0020] "Intermediate coaxial line" means the coaxial line arranged between the two end coaxial lines.

[0021] Preferably, the guide element is adapted to guide the larger diameter outer contact.

[0022] According to another advantageous embodiment variant, the guide element is integral with the external contact of the coaxial line which extends from the other of the longitudinal ends of the connector, opposite that from which the external contact mechanically guided by the guide tube extends.

[0023] Preferably, the guide element is integral with the outer contact of smaller diameter.

[0024] According to another advantageous embodiment, the guide element is overmolded around the external contact of the coaxial line.

[0025] According to this embodiment, the guide element is furthermore formed by forming an electrically insulating block. This electrically insulating block makes it possible to house and mechanically retain the central contact at least of the first coaxial line.

[0026] Advantageously, the guide element is further adapted to mechanically retain the external contact of the coaxial line, preferably to form an axial stop for the latter.

[0027] The central contacts of the coaxial lines are formed of a first electrically conductive body having at least two different diameters, respectively forming the central contact of a first coaxial line and the central contact of a second coaxial line, and of a second electrically conductive body, forming the central contact of a third coaxial line, sliding on the central contact of the second coaxial line, of larger diameter than that of the first coaxial line, the first electrically conductive body extending from one of the longitudinal ends of the connector and the second electrically conductive body extending from the other of its longitudinal ends. Advantageously, such a formation of the central contacts of the coaxial lines guarantees a stable electrical contact with a low resistance between the coaxial lines.

[0028] Preferably, the second electrically conductive body comprises an open end comprising petals in mechanical and electrical contact on the outer surface of the first electrically conductive body.

[0029] According to an advantageous embodiment variant, a single coaxial line sliding in another coaxial line, the third coaxial line, of larger diameter, the external contact of the third coaxial line being integral with the external contact of the second line with a diameter narrowing.

[0030] According to an advantageous embodiment, the unitary coaxial connector comprises: a third electrically conductive body, forming the external contact of a first coaxial line, integral with the guide element, preferably by being overmolded with the latter; a fourth electrically conductive body having two different diameters, respectively forming the external contact of a second coaxial line and the external contact of a third coaxial line, the external contact of the second coaxial line being sliding on the external contact of the first coaxial line, the external contact of the third coaxial line, of larger diameter than that of the second coaxial line, being mechanically guided by the guide element.

[0031] According to another advantageous embodiment, the connector comprises at least one elastic return means for returning the fourth electrically conductive body to an extreme deployed position relative to the third electrically conductive body. This elastic return means ensures the movement of the sliding external contact and the contact force with a PCB to which the connector is intended to be electrically connected.

[0032] According to this other embodiment, the elastic return means consists of a helical spring wound around between the guide tube and the outer contact of smaller diameter of the fourth electrically conductive body and in axial abutment on the one hand against a shoulder of the guide element and on the other hand against the shoulder forming the junction between the outer contact of smaller diameter and that of larger diameter of the fourth body.

[0033] According to another advantageous embodiment, the connector comprises at least one elastic return means for returning the second electrically conductive body to an extreme deployed position relative to the first electrically conductive body. This elastic return means ensures the movement of the sliding central contact and the contact force with a PCB to which the connector is intended to be electrically connected.

[0034] According to this other embodiment, the elastic return means consists of a helical spring housed in a bore of the central contact of larger diameter of the first electrically conductive body and in axial abutment against the blind end of a tube forming the central contact of the second electrically conductive body.

[0035] According to an advantageous embodiment: the guide element is electrically conductive and integral with the external contact formed by the third electrically conductive body; the first electrically conductive body a cylindrical sleeve forming the central contacts of the first and second coaxial lines and a contact tip mounted axially movable in the sleeve with an axial stop; the second electrically conductive body forming the central contact of the third coaxial line being slidably mounted relative to the fourth electrically conductive body forming the external contact of the second coaxial line and the external contact of the third coaxial line, so that the force exerted by each of the elastic return means can achieve the electrical connection between, on the one hand, at one of the longitudinal ends of the connector, the contact tip and the guide element and respectively the signal track and the ground track of a first printed circuit board (PCB1) and, on the other hand, at the other of the longitudinal ends of the connector, the central contact and the external contact of the third coaxial line and respectively the signal track and the ground track of a second printed circuit board (PCB2).

[0036] Thus, according to this mode, a board-to-board electrical connection (PCB 1, PCB2) can be made, solely by mechanical application force, and therefore without any soldering / brazing being necessary.

[0037] According to an advantageous insulation alternative, the connector comprises an electrically insulating block, arranged between the external contact and the central contact of the third coaxial line over at least part of the axial length of the latter, the electrically insulating block comprising at least one axial through hole. This insulating block makes it possible to improve the mechanical retention of the sliding central contact. The axial hole(s) over the length of the sliding coaxial line makes it possible to maintain a constant impedance. In this alternative, the diameter of the sliding coaxial line is increased.

[0038] According to an advantageous variant, the guide element comprises centering and / or mechanical retention feet adapted to position and / or pre-assemble, preferably by force fitting or by clipping, the element and thereby the connector to a printed circuit board (PCB1) to which a coaxial line of the connector is intended to be connected by being secured, in particular soldered.

[0039] The guide element, and where appropriate the electrically insulating block, is (are) advantageously made of an electrically insulating material chosen from an aliphatic polyamide (PA), a liquid crystal polymer (LCP), polyetheretherketone (PEEK) or a mixture thereof. This eliminates any use of plastic materials from the PFA family.

[0040] Preferably, the material constituting the contacts is a lead-free and beryllium-free copper alloy.

[0041] Advantageously, the external contact of one of the coaxial lines at a longitudinal end of the connector comprises at least one tab, intended to serve as a permanent electrical and mechanical connection with a printed circuit board (PCB1). This facilitates and strengthens the connection, in particular by providing a large soldering surface.

[0042] According to an advantageous structure, the external contact of one of the coaxial lines at a longitudinal end of the connector comprises at its free end, two concentric edges, one inside the other forming two staircase steps, and the external one extending radially outwards. This makes it possible to increase the radial misalignment acceptable by the connector, without influencing the impedance of the sliding coaxial line.

[0043] The invention also relates to a coaxial connection assembly, intended in particular to connect two printed circuit boards (PCB1, PCB2) or a board to a filter or a board to a module, comprising: at least one unitary coaxial connector according to the present invention, one of the coaxial lines at a longitudinal end of the connector is intended to be connected by being secured, in particular soldered, to a first printed circuit (PCB1), at least one interconnection plate one main face of which is intended to be connected by being secured, in particular soldered, to a second printed circuit (PCB2) or to a module or to a filter, and the other main face of which is intended to be connected to another of the coaxial lines at the other longitudinal end of the connector.

[0044] Preferably, the other of the coaxial lines at the other longitudinal end of the connector, intended to be connected to the other main face of the interconnection plate is the sliding one.

[0045] The coaxial connection assembly can be multi-way and include: several coaxial connectors arranged parallel to each other; several interconnection plates each intended to be connected to the other of the coaxial lines of each connector.

[0046] The invention also relates to a method for producing a unitary coaxial connector as described above, comprising the following steps: i / provision of a third electrically conductive body forming the external contact of a first coaxial line; ii / provision of a fourth electrically conductive body having two different diameters, respectively forming the external contact of a second coaxial line and the external contact of a third coaxial line, iii / mechanical assembly of a first connector subassembly comprising a first electrically conductive body having at least two different diameters, respectively forming the central contact of the first coaxial line and the central contact of the second coaxial line, and a second electrically conductive body forming the central contact of the third coaxial line, sliding on the central contact of the second coaxial line, of larger diameter than that of the first coaxial line;iv / overmolding the guide element onto the third electrically conductive body so as to form a second connector subassembly and then mechanically assembling the first subassembly in the second subassembly; or iv / overmolding the guide element both onto the third electrically conductive body and onto the central contact of the first coaxial line of the first connector subassembly so as to form a second connector subassembly; v / mechanically assembling the fourth electrically conductive body in the second subassembly so that the outer contact of the second coaxial line slides over the outer contact of the first coaxial line and the guide element mechanically guides the outer contact of the third coaxial line. ;

[0047] Preferably, the overmolding step iv / is carried out so as to form an electrically insulating block in the form of a hollow tube adapted to house the central contact of the first coaxial line.

[0048] According to an advantageous variant, assembly step iii / is carried out with a central contact of the third coaxial line in the form of a blind tube and with a central contact of the second coaxial line provided with a bore, and by housing a helical spring in the bore in axial abutment against the blind end of the tube.

[0049] According to another advantageous variant, the assembly step v / is carried out by first housing a helical spring around the external contact of the first coaxial line, in axial abutment on the one hand against a shoulder of the guide element and on the other hand against the shoulder forming the junction between the external contact of the second coaxial line and that of the third coaxial line.

[0050] Thus, the invention essentially consists of a unitary coaxial connector comprising three coaxial lines, mainly devoid of solid electrical insulation, of constant nominal impedances on each coaxial line, whatever the length of each of said coaxial lines, the nominal impedances being preferably equal and at least one of which slides into another adjacent one, and the diameters of the central and external contacts of which increase from one longitudinal end to the other of the connector, with a peripheral guide element, preferably in the form of a tube which makes it possible to guide and refocus the sliding external contact over a large length of movement.

[0051] The characteristic impedance of each coaxial line and of the entire connector remains at a stable value, typically 50 ohm, along the entire length of the connector, regardless of the final distance between the PCBs to be connected by the connector. It is also possible to obtain a stable impedance along the entire length of the connector at 75 ohms or any other value. There is no impedance mismatch along the axis of the connector, when passing from one coaxial line to another: the presence of air predominantly in the coaxial lines avoids impedance variations between areas of solid insulation and air insulation that can be found in connectors according to the state of the art.

[0052] The length adaptation of the connector according to the invention to meet the different distances between PCBs to be connected is carried out by varying the length of the sliding coaxial line: the outer or ground contact slides outside the body of the smaller diameter outer or ground contact, belonging to an end coaxial line, decreasing or increasing the length of the sliding coaxial line; the central contact, belonging to an end coaxial line slides above the smaller diameter central contact, decreasing or increasing the length of the sliding coaxial line.

[0053] The advantages of the invention compared to connectors according to the state of the art are numerous, among which we can cite: the possibility of obtaining large axial misalignments, typically of the order of 2.4 mm variation in the distance between two PCBs to be connected, and this without modification of the impedance of the coaxial lines as a function of the distance between PCBs, which remains stable, typically equal to 50 Ω; the absence of solid electrical insulators which leaves air as an insulator whose lower dielectric constant makes it possible to reduce the dimensions (diameters) of the coaxial lines and to obtain a compact connector. For example, the largest diameter coaxial line can have an external contact of 3.5 mm in diameter and a central contact of 1.5 mm; the functional separation between parts with electrical functions, such as the external contacts, and the external guide tube with mechanical functions of guiding and retaining the sliding external contact allows the implementation of materials most suited to these functions: the tube can be made of plastic,preferably overmolded on the fixed external contact of smaller diameter, the bodies of the external or ground contacts, due to their simplicity of geometry, do not require the use of copper alloy including beryllium or lead, which make it possible to obtain increased elasticity of the copper alloys, the low number of connection maneuvers required for the connector requires a lower mechanical performance of the materials used in the metal parts and therefore also makes it possible to use copper alloys without beryllium or lead, the electrical parts serving as current carriers, not providing a structural mechanical function, can be made with very low thicknesses, which allows a saving in material, weight, cost, etc., the main use of air lines, where appropriate with a solid insulator that is as compact as possible,avoids the use of plastics from the PFA family. The plastics used for the tube and the solid insulator can be from the PA, LCP, PEEK family. These plastics combined with the use of beryllium- and lead-free metals for the contacts therefore avoid the use of hazardous or prohibited substances; the possibility of large axial misalignment, typically equal to + / -1.2 mm, facilitated by the guidance of the sliding outer contact by the guide tube; the possibility of large radial misalignment on a PCB to be connected, typically equal to + / -0.75 mm, by the end shapes of the central and external sliding contacts and by the sliding interlocking of the coaxial lines; the simplicity of geometry of the connector components and their assembly; reduced component and assembly costs; high operating frequency due to the stability of the impedance of the coaxial lines,typically equal to 20 GHz with an impedance of 50 ohms. ,

[0054] Other advantages and characteristics of the invention will become more apparent upon reading the detailed description of examples of implementation of the invention given by way of illustration and not limitation with reference to the following figures. Brief description of the drawings

[0055] [ Fig 1], [Fig 1A ], [ Fig 1B ] THE Figures 1, 1A , 1B represent in perspective view and in longitudinal sections respectively an example of a unitary coaxial connector according to a first embodiment of the invention, the Figures 1A And 1B being made according to the same cutting plan but with a greater compression stroke for the Figure 1B . [ Fig 2 ] there figure 2 is an exploded view of the connector according to the Figures 1 to 1B . [ Fig 3 ] there figure 3is a perspective view of an external contact of a coaxial line at one end of the connector according to the Figures 1 to 1B . [ Fig 4 ] there figure 4 is a perspective view of another connector subassembly comprising the three central contacts of the coaxial lines of the connector according to the Figures 1 to 1B . [ Fig 5 ] there Figure 5 is a perspective and longitudinal sectional view of a connector subassembly comprising an external contact according to the figure 3 and a guide tube overmolded on said contact. Fig 6 ] there figure 6 is a perspective and longitudinal sectional view of a unitary coaxial connector according to an alternative of the invention. Fig 7 ] there figure 7 is a perspective view of an interconnection plate intended to be interposed between a longitudinal end of a unitary coaxial connector according to the invention and a PCB. Fig 8 ] there figure 8is a perspective view of a PCB provided with a plurality of interconnection plates according to the figure 7 for the implementation of a multi-channel coaxial connection assembly. [ Fig 9 ] there figure 9 is a perspective view of a multi-way coaxial connection assembly comprising a plurality of unitary coaxial connectors according to the invention arranged in parallel with each other and connected between a PCB and a PCB provided with the plurality of interconnection plates according to the figure 8 . [ Fig 10 ] there figure 10 represents in longitudinal section an example of a unitary coaxial connector according to a second embodiment of the invention, intended to make an electrical connection between two PCBs, without soldering. Fig 11 ] there figure 11 is an exploded view of the connector according to the figure 10 . Detailed description

[0056] It has been represented on the figures 1 to 2, a unitary coaxial connector 1 according to a first embodiment of the invention, in its assembled configuration, in an intermediate deployed position.

[0057] The connector 1 extends along a longitudinal axis X, is assembled to form a single object intended to transmit RF radiofrequency signals.

[0058] This unitary coaxial connector essentially comprises three coaxial lines 2, 3, 4 adjacent along the longitudinal axis X and whose diameter increases from one line to the other adjacent, from one of the longitudinal ends 10 of the connector to the other 11 of its longitudinal ends. The increasing diameter of the coaxial lines makes it possible to obtain at one of the ends of the coaxial connector 1 a greater tolerance to radial misalignment with the device to be connected (PCB, filter, etc.).

[0059] These three lines 2, 3, 4 have constant nominal impedances along the length of each of the lines. Preferably, the nominal impedances of all the coaxial lines are equal.

[0060] The coaxial line 2 comprises an outer or ground contact 20 and a central contact 21 arranged inside the outer contact 20. The diameter of the central contact 21 is adapted to obtain a constant impedance, typically 50 ohms, over the entire length of the coaxial line 2.

[0061] The coaxial line 3 comprises an external or ground contact 30, of larger diameter than the external contact 20, allowing an improvement in the continuity of the contacts and therefore in the RF performance, and a central contact 31 arranged inside the external contact 30 and of larger diameter than the central contact 21. The external contact 30 slides onto the external contact 20. The central contact 31 is integral, preferably formed integrally with the central contact 21.

[0062] The coaxial line 4 comprises an external or ground contact 40, of larger diameter than the external contact 30 and a central contact 41 arranged inside the external contact 40 and of larger diameter than the central contact 31. The external contact 40 is integral, preferably formed integrally with the external contact 30.

[0063] As illustrated, the outer contact 40 preferably comprises at its free end, two concentric rims 400, 401, one inside the other forming two staircase steps, and the outer one extending radially outward. The inner concentric rim 401 makes it possible to radially offset outwardly the bearing surface of the outer contact 40 with the mass of the PCB or the filter. The outer concentric rim 400 makes it possible to create the bearing surface of the outer contact against the mass of the PCB or the filter. The flare formed by the two concentric rims 400, 401 at the end of the outer contact allows an increase in the radial misalignment tolerance. The central contact 41 slides onto the central contact 31. The central contact 41 comprises at its open end petals 411 in mechanical and electrical contact on the outer surface of the central contact 31.The length of this central contact 41 is exactly that of the coaxial line 4 allowing a constant impedance of the latter.

[0064] As visible on the Figures 1A And 1B , the volumes between the central contacts 21, 31, 41 and the external contacts 20, 30, 40 are filled with air, or with an electrically non-conductive gas, or constituted of vacuum, that is to say without solid electrical insulation over at least the sliding length along the longitudinal axis X. The absence of solid electrical insulation in the coaxial line 3 allows the external contact 20 to penetrate under the external contact 30, and the central contact 41 to slide around the central contact 31.

[0065] A guide element 5, preferably in the form of a hollow tube, has an inner surface which is adapted to mechanically guide the outer contact 40. As is apparent from the Figures 1A And 1B, this element in the form of an external guide tube 5, preferably overmolded on the external contact 20, plays the role of mechanical structure of the connector. It therefore makes it possible both to stiffen this external contact 20, by its base 50 which surrounds it, to protect all the external contacts 20, 30, 40 and to confer the mechanical robustness of the connector 1. Due to the significant axial travel of the external contact 40, the guide tube 5 prevents the deviation of the external contact 40, particularly when the latter is fully deployed.

[0066] The guide element 5 is distinct from each of the coaxial lines 2, 3, 4, in particular from each external contact 20, 30, 40 of each of the coaxial lines 2, 3, 4.

[0067] This guide tube 5 is advantageously made of an electrically insulating material chosen from an aliphatic polyamide (PA), a liquid crystal polymer (LCP), polyetheretherketone (PEEK) or a mixture thereof.

[0068] The fully tubular shape of element 5 helps reduce the overall size of the connector. However, only its tubular inner surface is used for guidance; its outer shape can vary depending on the application or requirement.

[0069] The coaxial line 3 has a variable electrical length, due to the synchronous sliding of the ground contact 30 on the ground contact 20 and the sliding of the central contact 41 on the central contact 31.

[0070] The transition zones Z1 between coaxial lines 2 and 3 on the one hand, and Z2 between coaxial lines 3 and 4 on the other hand, have an invariant design, i.e. diameter ratios between ground contact and central contact which are equal, with a stable impedance, typically equal to 50 ohms, and this whatever the deployed position, i.e. sliding of the coaxial lines of the connector. This makes it possible to operate the connector 1 according to the invention beyond 12 GHz, preferably up to 20 GHz.

[0071] In the mode illustrated in Figures 1 to 1B , the unitary coaxial connector 1 includes: a first electrically conductive body 14 having two different diameters, respectively forming the central contact 21 of the coaxial line 2 and the central contact 31 of the coaxial line 3; a second electrically conductive body 15 forming the central contact 41 of the coaxial line 4 sliding on the central contact 31 of the coaxial line 3; a third electrically conductive body 12, forming the external contact 20 of the coaxial line 2, the guide tube 5 being overmolded around by its base portion 50; a fourth electrically conductive body 13 having two different diameters, respectively forming the external contact 30 of the coaxial line 3 and the external contact 40 of the coaxial line 4, the latter being mechanically guided by the guide tube 5.

[0072] A helical spring 6 is wound between the guide tube 5 on the one hand, and the external contacts 20 and 30 on the other hand, and in axial abutment on the one hand against a shoulder of the guide tube 5 and on the other hand against the shoulder forming the junction between the external contact 30 and the external contact 40. This spring 6 ensures the sliding of the external or ground body 13 and the contact force with the PCB to which the longitudinal end 11 of the connector is intended to connect.

[0073] A helical spring 7 is housed in a bore 310 of the central contact 31 and in axial abutment against the blind end 410 of a tube forming the central contact 41. This spring 7 ensures the movement of the central contact 41 and the contact force with the PCB to which the longitudinal end 11 of the connector is intended to connect.

[0074] These helical springs can be replaced by any other suitable elastic return means (elastic washers, cut metal part, etc.).

[0075] There figure 3 shows the electrically conductive body 12 which forms the external contact 20. The free end of the latter comprises petals 200 ensuring electrical contact, by their external faces, with the external contact 30 which slides over it. This configuration makes it possible to guarantee better contact pressure.

[0076] The base of the body 12 advantageously comprises legs 22 orthogonal to the X axis, intended to serve as a permanent electrical and mechanical connection with a printed circuit board (PCB1), in particular by soldering, allowing surface mounting according to SMT technology. These legs 22 could also be arranged parallel to the X axis for through-soldering with the PCB, or mounting by press-fitting inside a hole in the PCB.

[0077] The body 12 also comprises at its base openings 23 allowing the guide tube 5 to be produced by overmolding onto the body 12. Advantageously, this overmolding of the outer tube 5 also allows an electrical insulating block 51 to be produced at the same time, as illustrated in Figures 1A And 1B , in which a smaller diameter portion of the central contact 21 is mechanically retained. The openings 23 have the shape of oblong through holes. Other shapes are possible depending on the technical constraints of overmolding the tube, and where appropriate the electrical insulating block.

[0078] The outer guide tube 5 preferably comprises centering and / or mechanical retention feet 53 adapted to position and pre-assemble, preferably by force fitting or by clipping, the tube and thereby the connector to a printed circuit board (PCB1) to which the coaxial line 2 of the connector is intended to be connected by being secured, in particular soldered. This pre-assembly can be carried out by force fitting or by clipping. The number of centering and / or mechanical retention feet can vary depending on the technical constraints of assembly on the PCB.

[0079] Advantageously, the guide tube 5 also provides a mechanical retention and axial stop function for the outer body 13. To do this, the outer contact 40 comprises outwardly oriented tabs or stampings 42 which each slide in a through opening 52 made in the guide tube 5 and can come into axial abutment against their edge.

[0080] The mechanical operation of the coaxial connector 1 is essentially as follows: during a connection between two PCBs or between a PCB and a filter or a module, the connector 1 can be compressed between its two longitudinal ends 10 and 11 due to the reduction in length by sliding the coaxial line 3. The outer or ground contact 30 slides outside the outer or ground contact 20 and the central contact 41 slides simultaneously on the central contact 31. The helical springs 6 and 7 provide the contact forces necessary for the electrical connection. The flanges 400, 401 of the outer contact 40 make it possible to increase the acceptable radial misalignment, without influencing the impedance of the coaxial line 4 of the connector, due to the short axial length of each of the flanges.In order to reach the folded connection position of the connector 1, the bodies 13 and 15 move essentially synchronously, in order to slide respectively on the bodies 12 and 14, thus reducing the length of the coaxial line 3.

[0081] In some configurations of a connector 1 contacting a PCB or a filter, the flange 401 of the outer contact 40 and the end 410 of the central contact 41 may be significantly offset longitudinally. In other words, the flange 401 and the end 410 may not be coplanar.

[0082] When connecting the connector 1 with this PCB or this filter, the edge 401 and the end 410 come into contact with the respective surfaces opposite the filter, putting the elastic elements 6 and 7 into mechanical pre-stress.

[0083] Then, the connector 1 is folded between its two longitudinal ends 10 and 11 in order to reach its connection length by sliding the coaxial line 3. The external ground contact 30 and the central contact 41 then slide simultaneously, respectively on the external contact 20 and the central contact 31.

[0084] The assembly process of the single coaxial connector 1 just described comprises the following steps: i / provision of the third electrically conductive body 12 forming the external contact 20 ( figure 3); ii / provision of a fourth electrically conductive body 13 comprising two different diameters, respectively forming the external contact 30 and the external contact 40; iii / mechanical assembly of a first connector subassembly 17 comprising a first electrically conductive body 14 having two different diameters, respectively forming the central contact 21 and the central contact 31, and a second electrically conductive body 15 forming the central contact 41, sliding on the central contact 31 ( figure 4 ). This step iii / preferably comprises housing the helical spring 7 in the bore 310 of the central contact 31, which is in axial abutment against the free end 410 of the blind tube forming the central contact 41; iv / overmolding the guide tube 5 on the third electrically conductive body so as to form a second connector subassembly 16 ( Figure 5) then mechanical assembly of the first subassembly 17 in the second subassembly 16. Preferably, the central contact 21 is held in the central electrical insulator 51 formed by the overmolding; or iv' / overmolding of the guide tube 5 both on the third electrically conductive body 12 and on the central contact 21 of the coaxial line 2 of the first connector subassembly 17 so as to form a second connector subassembly; vi / mechanical assembly of the fourth electrically conductive body 13 in the second subassembly 16 so that the outer contact 30 slides on the outer contact 20 and the guide tube 5 mechanically guides the outer contact 40.Beforehand, the helical spring 6 is wound around the external contact 20 and, when the body 13 is inserted, comes into axial abutment on the one hand against a shoulder of the guide tube 5 and on the other hand against the shoulder forming the junction between the external contact 30 and the external contact 40.

[0085] Advantageously, the electrically conductive bodies are obtained by stamping.

[0086] Alternatively, step iv' / can be carried out with overmolding of the central electrical insulator 51.

[0087] There figure 6illustrates an alternative embodiment of the coaxial connector 1, which comprises an electrically insulating block 8, arranged between the external contact 40 and the central contact 41 of the third coaxial line 4 over at least part of the axial length of the latter, preferably over its entire axial length. In the case where the insulating block 8 partially occupies the length of the coaxial line 4, an impedance matching must be carried out between the area integrating the block and that without solid insulation.

[0088] This electrically insulating block 8 comprises at least one axial through hole 80, preferably a plurality distributed regularly angularly around the axis X. This insulating block 8 makes it possible to improve the mechanical retention of the sliding central contact 41. The axial hole(s) along the length of the sliding coaxial line 4 makes it possible to reduce the dielectric constant compared to a solid body and to approach that of air. In this alternative, the diameter of the sliding coaxial line 4 is increased compared to that without insulating block 8.

[0089] The electrically insulating block 8 is preferably made of an electrically insulating material chosen from an aliphatic polyamide (PA), a liquid crystal polymer (LCP), polyetheretherketone (PEEK) or a mixture thereof.

[0090] Finally, the electrically insulating block 8 is not fixed to both the outer contact 40 and the central contact 41, allowing a slight relative axial sliding between these two contacts when pre-stressing against the PCB or the filter to be connected.

[0091] PCBs that are to be connected together by one or more coaxial connectors 1 that have just been described may use fragile coatings that are not compatible with the bearing and friction forces of the coaxial connectors 1. These coatings, typically made of tin, allow cost savings.

[0092] To ensure support and friction in order to establish a reliable connection between a single coaxial connector 1 and a PCB, the inventors have provided an interconnection plate 9 as illustrated in figure 7 . The 9 interconnection plate simplifies the PCB and reduces its manufacturing cost.

[0093] This interconnection plate 9 has a main face 90 which is intended to be connected by being secured, in particular soldered, to a printed circuit (PCB2) or to a module or to a filter. The other main face 91 is intended to be connected to the coaxial line 4 of the connector. Thus, it has two concentric electrically conductive tracks 910, 911 separated by an electrical insulator. These tracks 910, 911, intended to be in support respectively with the external contact 40 and the central contact 41, can be made of a hard metal coating, typically of nickel-gold alloy or silver, which is compatible with the pressure applied by a coaxial connector 1.

[0094] Thus, an interconnection plate 9 makes it possible to reliably route the signal to be transmitted, between on the one hand the central contacts 21, 31, 41 and the signal track of the PCB2 and on the other hand the external contacts 20, 30, 40 of the coaxial connector 1 and the electrical ground of the PCB2.

[0095] There figure 8 shows part of a multi-way coaxial connection assembly 100 with a PCB2 on which several interconnection plates 9.1 to 9.8 are arranged and secured in parallel to each other.

[0096] There figure 9 shows the multi-way assembly 100 with a plurality of coaxial connectors 1.1 to 1.8 each connected by their coaxial line 2 to a PCB1 and to the PCB2 via their coaxial line 4 and an interconnection plate 9.1 to 9.8 secured as according to the figure 8 .

[0097] THE figures 10 And 11show a second embodiment of the unitary coaxial connector 1 according to the invention, intended to be connected, without soldering or brazing, by its two ends to two PCBs.

[0098] The first electrically conductive body 14 here comprises two components, namely a cylindrical sleeve forming the central contact 31 and the central contact 21 with a free end in the form of a split sleeve 211 and a contact tip 25, providing the electrical connection between the central contact 21 and the printed circuit PCB1, mounted axially movable in the sleeve 31, 21 with an axial stop provided by an outer shoulder 210 in an inner shoulder of the sleeve 31, 21.

[0099] The elastic element 7 exerts a force on the shoulder 210 of the contact tip 25, in order to ensure contact pressure with one of the two PCBs, such as PCB1.

[0100] The cylindrical sleeve 31, 21 is integral with the electrically insulating block 51, for example by being force-fitted into an opening in the insulator 51. The electrical insulator 51 is itself integral with the external contact 20.

[0101] The guide element 5 is integral with the external contact 20. The guide element 5 is here electrically conductive to ensure the electrical connection with the ground track of the PCB1, by its base portion 50 in the form of a crown. Furthermore, given the more compact geometry of the connector according to this second embodiment, the guide element 5 can advantageously be made of a metallic material, in particular by machining. The guide element 5 comprises an internal surface mechanically guiding the external contact 40. The guide element 5 can also axially retain the external contact 40, in particular by means of hooking tabs 500 at its free end which hook onto a shoulder of the external contact 40.

[0102] The contact tip 25, movable relative to the external contact 20 and therefore to the guide element 5, makes it possible to ensure the electrical signal connection with the PCB1 under all circumstances. The guide element 5 simultaneously ensures the electrical ground connection with the PCB1.

[0103] The electrical signal passing through the sleeve 31, 21 is transmitted to the contact tip 25 via the petals of the split sleeve 211 at the free end.

[0104] The second body 15 is integral with the electrical insulator 8, in particular by force fitting. The electrical insulator 8 is slidably mounted in the external contact 40, which makes it possible to electrically connect both the external contact 40 with the ground track of the other of the two PCBs, such as PCB2 and the central contact 41 with the signal track of PCB2.

[0105] The electrical insulator 8 is retained axially in the external contact 40, in particular by means of tabs 402 of the latter which are inserted into an opening 81 of the insulator 8.

[0106] Thus, a single coaxial connector 1 according to this second embodiment, as illustrated in figures 10 And 11 , establishes the electrical contacts at each of these ends, solely by the force exerted by each of the elastic elements 6 and 7 with the signal and ground tracks of PCB1 and PCB2. No soldering or welding is therefore required.

[0107] Other variations and improvements may be provided without departing from the scope of the invention.

Claims

1. Unitary coaxial connector (1), intended to connect two parallel printed circuits (PCB1, PCB2) for transmitting RF radiofrequency signals, with longitudinal axis X, comprising: - three coaxial lines (2, 3, 4) adjacent along the longitudinal axis X and whose diameter increases from one adjacent line to the other, from one of the longitudinal ends (10) of the connector to the other of its longitudinal ends (11), each of the lines comprising a central contact (21, 31, 41) and an external contact (20, 30, 40) arranged around the central contact, at least one central contact of a coaxial line being sliding in a central contact of one of the other lines adjacent to it, at least one external contact of a coaxial line being sliding in an external contact of one of the other lines adjacent to it so that the length of the intermediate coaxial line can vary,the volume between the central contact and the external contact of the intermediate line being devoid of solid electrical insulation, the central contacts of the coaxial lines being formed of a first electrically conductive body (14) having at least two different diameters, respectively forming the central contact (21) of a first coaxial line and the central contact (31) of a second coaxial line, and of a second electrically conductive body (15), forming the central contact (41) of a third coaxial line, sliding on the central contact of the second coaxial line, of larger diameter than that of the first coaxial line, the first electrically conductive body extending from one of the longitudinal ends (10) of the connector and the second electrically conductive body extending from the other of its longitudinal ends (11); - a guide element (5), preferably in the form of a hollow tube,whose internal surface is adapted to mechanically guide at least the external contact of the coaxial line which extends from one of the longitudinal ends of the connector., 2. A unitary coaxial connector according to claim 1, the second electrically conductive body comprising an open end comprising petals (411) in mechanical and electrical contact on the outer surface of the first electrically conductive body.

3. Unitary coaxial connector according to one of the preceding claims, the guide element being integral with the external contact (20) of the coaxial line which extends from the other of the longitudinal ends of the connector, opposite that from which the external contact mechanically guided by the guide tube extends, preferably the guide element being integral with the external contact of smaller diameter.

4. Unitary coaxial connector according to one of the preceding claims, the guide element being further adapted to mechanically retain the external contact (40) of the coaxial line, preferably to form an axial stop for the latter.

5. Unitary coaxial connector according to one of the preceding claims, a single coaxial line being slidable in another coaxial line, the external contact of the third coaxial line being integral with the external contact of the second line with a diameter narrowing.

6. Unitary coaxial connector according to claim 5, comprising: - a third electrically conductive body (12), forming the external contact (20) of the first coaxial line, integral with the guide element, preferably being overmolded with the latter;- a fourth electrically conductive body (13) having two different diameters, respectively forming the external contact (30) of the second coaxial line and the external contact (40) of the third coaxial line, the external contact of the second coaxial line being sliding on the external contact of the first coaxial line, the external contact of the third coaxial line, of larger diameter than that of the second coaxial line, being mechanically guided by the guide element, preferably the connector comprising at least one elastic return means for returning the fourth electrically conductive body to an extreme deployed position relative to the third electrically conductive body.; 7. Unitary coaxial connector according to one of the preceding claims, comprising at least one elastic return means for returning the second electrically conductive body to an extreme deployed position relative to the first electrically conductive body, preferably the elastic return means consisting of a helical spring (7) housed in a bore (310) of the central contact (31) of larger diameter of the first electrically conductive body and in axial abutment against the blind end (410) of a tube forming the central contact (41) of the second electrically conductive body.

8. Unitary coaxial connector according to claim 7 in combination with claim 6, wherein: - the guide element (5) is electrically conductive and integral with the external contact (20) formed by the third electrically conductive body; - the first electrically conductive body (14) comprises a cylindrical sleeve forming the central contacts (31, 21) of the first and second coaxial lines and a contact tip (25), mounted axially movable in the sleeve (31, 21) with an axial stop;- the second electrically conductive body (15) forming the central contact (41) of the third coaxial line being slidably mounted relative to the fourth electrically conductive body (13) forming the external contact (30) of the second coaxial line and the external contact (40) of the third coaxial line, so that the force exerted by each of the elastic return means (6, 7) can make the electrical connection between, on the one hand, at one of the longitudinal ends (10) of the connector, the contact tip and the guide element and respectively the signal track and the ground track of a first printed circuit board (PCB1) and, on the other hand, at the other of the longitudinal ends (11) of the connector, the central contact (41) and the external contact (40) of the third coaxial line and respectively the signal track and the ground track of a second printed circuit board (PCB2).; 9. Unitary coaxial connector according to one of claims 6 to 8, comprising an electrically insulating block (8), arranged between the external contact (40) and the central contact (41) of the third coaxial line over at least part of the axial length of the latter, the electrically insulating block comprising at least one axial through hole (80).

10. Unitary coaxial connector according to one of the preceding claims, with the exception of claim 8, the guide element being made of an electrically insulating material chosen from an aliphatic polyamide (PA), a liquid crystal polymer (LCP), polyetheretherketone (PEEK) or a mixture thereof.

11. Unitary coaxial connector according to one of the preceding claims, the material constituting the contacts being a copper alloy free of lead and beryllium.

12. Unitary coaxial connector according to one of the preceding claims, with the exception of claim 8, the external contact (20) of one of the coaxial lines at a longitudinal end of the connector comprising at least one tab (22), intended to serve as a permanent electrical and mechanical connection with a printed circuit board (PCB1).

13. Unitary coaxial connector according to one of the preceding claims, the external contact (40) of one of the coaxial lines at a longitudinal end of the connector comprising at its free end, two concentric edges (400, 401), one inside the other forming two staircase steps, and the external one extending radially outwards.

14. Coaxial connection assembly (100), configured to connect two parallel printed circuit boards (PCB1, PCB2), comprising: - at least one unitary coaxial connector (1) according to any one of the preceding claims, one of the coaxial lines (2) at a longitudinal end (10) of the connector is intended to be connected by being secured, in particular soldered, to a first printed circuit (PCB1), - at least one interconnection plate (9) one main face of which is intended to be connected by being secured, in particular soldered, to a second printed circuit (PCB2), and the other main face of which is intended to be connected to another of the coaxial lines (4) at the other longitudinal end (11) of the connector.

15. Method for producing a unitary coaxial connector according to claim 6 or one of claims 7 and 9 to 13, in combination with claim 6, comprising the following steps: i / providing the third electrically conductive body forming the external contact of a first coaxial line;ii / providing the fourth electrically conductive body having two different diameters, respectively forming the external contact of a second coaxial line and the external contact of a third coaxial line, iii / mechanical assembly of a first connector subassembly comprising the first electrically conductive body having at least two different diameters, respectively forming the central contact of the first coaxial line and the central contact of the second coaxial line, and the second electrically conductive body forming the central contact of the third coaxial line, sliding on the central contact of the second coaxial line, of larger diameter than that of the first coaxial line; iv / overmolding the guide element on the third electrically conductive body so as to form a second connector subassembly then mechanical assembly of the first subassembly in the second subassembly;or iv / ' overmolding the guide element on both the third electrically conductive body and the central contact of the first coaxial line of the first connector subassembly so as to form a second connector subassembly; v / mechanical assembly of the fourth electrically conductive body in the second subassembly so that the outer contact of the second coaxial line slides on the outer contact of the first coaxial line and the guide element mechanically guides the outer contact of the third coaxial line.;