Unitary RF coaxial connector for board-to-board or board-to-filter or board-to-module connection, with three adjacent coaxial lines of increasing diameter, at least one of which slides into another, with constant impedance matching along the connector axis.

Abstract

Unitary RF coaxial connector for board-to-board or board-to-filter or board-to-module connection, with three adjacent coaxial lines of increasing diameter, at least one of which slides into another, with constant impedance matching along the connector axis.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 of the connector to the other, with a peripheral guide element (5) which makes it possible to guide and refocus the sliding external contact over a large displacement length. Figure for the abstract: Fig.1A.

Description

Title of the invention: Unitary RF coaxial connector for a board-to-board or board-to-filter or board-to-module connection, with three adjacent coaxial lines of increasing diameter, at least one of which slides into another, with constant impedance matching along the axis of the connector. 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 in particular be used to connect two parallel printed circuits, usually called board-to-board (B2B) connection or printed circuit board (PCB) to another component such as a module or a filter, generally called 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 even a 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” is meant 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 higher frequency RF signals. For board-to-board connectivity, the market also demands smaller, cheaper, and more modular devices.

[0009] There are already on the market and in the prior art examples 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 as close as possible 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] Commercial products already exist 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 small axial travel and a small radial positioning tolerance. Also, the frequencies for which these connectors are intended are not high.

[0013] Mention may also be made of the coaxial compression connectors marketed by the company 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°. On the other hand, the connector is not suitable for offering a wide range of axial distance between the two boards.

[0015] More generally, there is a need to further improve the card-to-card or card-to-module or card-to-filter connections, in particular to meet the specifications set by the inventors, namely:

[0016] - a connector of very simple structure, which consists of a minimum of parts detached, and which minimizes environmental impact by not using hazardous substances such as per- and polyfluoroalkyl substances (PFAS), lead or beryllium;

[0017] -a simple structure and a low-cost connector;

[0018] - the possibility of using a connector reference for a wide range of axial positioning between two parallel printed boards, typically + / - 1 mm or + / - 1.5 mm;

[0019] - the possibility of connecting two printed boards, parallel, radially offset relative to each other, typically with a radial misalignment of + / -0.5 mm to + / - 1 mm;

[0020] - a size and therefore an external diameter, typically less than 5 mm;

[0021] - an operating frequency range from DC to 20 GHz.

[0022] The invention aims to meet all or part of this need. Statement of the invention

[0023] 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:

[0024] - three adjacent coaxial lines along the longitudinal axis X and whose diameter is increasing from one line to the other adjacent line, 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 slidable in a central contact of one of the other lines adjacent to it, at least one external contact of a coaxial line being slidable 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;

[0025] 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.

[0026] By "devoid of solid electrical insulator" is meant that the electrical insulator consists of air or an electrically non-conductive gas, for example nitrogen, or a vacuum.

[0027] By “solidary” we mean fixed or made integrally with.

[0028] By "intermediate coaxial line" is meant the coaxial line arranged between the two end coaxial lines.

[0029] Preferably, the guide element is adapted to guide the larger diameter outer contact.

[0030] 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.

[0031] Preferably, the guide element is integral with the outer contact of smaller diameter.

[0032] According to another advantageous embodiment, the guide element is overmolded around the external contact of the coaxial line.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] According to an advantageous embodiment, the unitary coaxial connector comprises:

[0037] - a first electrically conductive body, forming the external contact of a first coaxial line, integral with the guide element, preferably being overmolded with the latter;

[0038] - a second 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;

[0039] - a third electrically conductive body having at least two diameters different, respectively forming the central contact of the first coaxial line and the central contact of the second coaxial line;

[0040] - a fourth 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.

[0041] 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 external contact and the contact force with a PCB to which the connector is intended to be electrically connected.

[0042] 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 second 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 an injunction between the outer contact of smaller diameter and that of larger diameter of the second body.

[0043] 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 central contact and the contact force with a PCB to which the connector is intended to be electrically connected.

[0044] 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 third electrically conductive body and in axial abutment against the blind end of a tube forming the central contact of the fourth electrically conductive body.

[0045] According to an advantageous embodiment: - the guide element is electrically conductive and integral with the external contact formed by the first electrically conductive body; - the third 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 fourth electrically conductive body forming the central contact of the third coaxial line being slidably mounted relative to the second electrically conductive body forming the external contact of the second coaxial line and the external contact of the third coaxial line,

[0046] so that the force exerted by each of the elastic return means can make 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).

[0047] Thus, according to this mode, a board-to-board electrical connection (PCB1, PCB2) can be made, solely by mechanical application force, and therefore without any soldering / brazing being necessary.

[0048] 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 a portion 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.

[0049] 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.

[0050] 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.

[0051] Preferably, the material constituting the contacts is a copper alloy free of lead and beryllium.

[0052] 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.

[0053] 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.

[0054] 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:

[0055] - at least one unitary coaxial connector according to any one of the claims previous ones, 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),

[0056] - 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.

[0057] 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.

[0058] The coaxial connection assembly may be multi-channel and comprise:

[0059] - several coaxial connectors arranged parallel to each other;

[0060] - several interconnection plates each intended to be connected to the other of the coaxial lines from each connector.

[0061] The invention also relates to a method for producing a unitary coaxial connector as described above, comprising the following steps:

[0062] i / providing a first electrically conductive body forming the external contact of a first coaxial line;

[0063] ii / provision of a second 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,

[0064] iii / mechanical assembly of a first connector subassembly comprising a third 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 fourth 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;

[0065] iv / overmolding of the guide element on the first electrically conductive body so as to form a second connector subassembly then mechanical assembly of the first subassembly in the second subassembly;

[0066] or

[0067] iv / ' overmolding the guide element both on the first electrically conductive body and on the central contact of the first coaxial line of the first connector subassembly so as to form a second connector subassembly;

[0068] v / mechanical assembly of the second electrically conductive body in the second subassembly so that the external contact of the second coaxial line slides on the external contact of the first coaxial line and the guide element mechanically guides the external contact of the third coaxial line.

[0069] 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.

[0070] According to an advantageous variant, the 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.

[0071] 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.

[0072] 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.

[0073] The characteristic impedance of each coaxial line and of the entire connector remains at a stable value, typically 50 ohms, over 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 over 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 the impedance variations between areas of solid insulation and air insulation that can be found in connectors according to the state of the art.

[0074] 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:

[0075] - the external or ground contact slides outside the body of the external contact or smaller diameter mass, belonging to an end coaxial line, decreasing or increasing the length of the sliding coaxial line;

[0076] - the central contact, belonging to an end coaxial line slides above of the smaller diameter center contact, decreasing or increasing the length of the sliding coaxial line.

[0077] The advantages of the invention compared to connectors according to the state of the art are numerous, among which we can cite:

[0078] - the possibility of obtaining large axial misalignments, typically of the order 2.4 mm variation in the distance between two PCBs to be connected, without modification of the impedance of the coaxial lines depending on the distance between PCBs, which remains stable, typically equal to 50 Q;

[0079] - the absence of solid electrical insulators which leaves air as an insulator, the most of which Low dielectric constant allows to reduce the dimensions (diameters) of coaxial lines and obtain a compact connector. For example, the largest diameter coaxial line can have an outer contact of 3.5 mm diameter and a central contact of 1.5 mm;

[0080] - functional separation between parts with electrical functions, such as contacts exteriors, and the exterior guide tube with mechanical functions of guiding and retaining the sliding exterior 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,

[0081] • the bodies of the external or ground contacts, due to their simplicity of geometry, do not require the use of copper alloys including beryllium or lead, which allow for increased elasticity of copper alloys,

[0082] * the low number of connection maneuvers required for the connector requires lower mechanical performance of the materials used in metal parts and therefore also allows the use of copper alloys without beryllium or lead, • electrical parts acting as current carriers, not providing a structural mechanical function, can be produced with very low thicknesses, which allows a saving in material, weight, cost, etc.,

[0083] • the main use of air lines, where appropriate with a solid insulator as compact as possible, avoids the use of plastics from the PFA family. The plastics used for the tube and solid insulation can be from the PA, LCP, PEEK family. These plastics combined with the use of beryllium- and lead-free metals for contacts therefore avoid the use of dangerous or prohibited substances;

[0084] - the possibility of a large axial misalignment, typically equal to + / -1.2 mm, facilitated by the guidance of the sliding external contact by the guide tube;

[0085] - 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;

[0086] - the simplicity of geometry of the connector components and their assembly;

[0087] - reduced component and assembly costs;

[0088] - a 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.

[0089] 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

[0090] [Fig.l], [Fig.lA], [Fig.lB] Figures 1, 1A, 1B show in perspective view and in longitudinal sections respectively an example of a unitary coaxial connector according to a first embodiment of the invention, Figures 1A and 1B being produced according to the same section plane but with a greater compression stroke for [Fig.lB].

[0091] [Fig.2] [Fig.2] is an exploded view of the connector according to Figures 1 to 1B.

[0092] [Fig.3] [Fig.3] is a perspective view of an external contact of a line coaxial at one end of the connector according to figures 1 to 1B.

[0093] [Fig.4] [Fig.4] is a perspective view of another connector subassembly comprising the three central contacts of the coaxial lines of the connector according to Figures 1 to 1B.

[0094] [Fig.5] [Fig.5] is a perspective and longitudinal sectional view of a connector subassembly comprising an external contact according to [Fig.3] and a guide tube overmolded on said contact.

[0095] [Fig.6] [Fig.6] is a perspective and longitudinal sectional view of a unitary coaxial connector according to an alternative of the invention.

[0096] [Fig.7] [Fig.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.

[0097] [Fig.8] [Fig.8] is a perspective view of a PCB provided with a plurality of interconnection plates according to [Fig.7] for implementing a multi-channel coaxial connection assembly.

[0098] [Fig.9] [Fig.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 [Fig.8].

[0099] [Fig. 10] [Fig. 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.

[0100] [Fig.11] [Fig.11] is an exploded view of the connector according to [Fig.10]. Detailed description

[0101] Figures 1 to 2 show a single coaxial connector 1 according to a first embodiment of the invention, in its assembled configuration, in an intermediate deployed position.

[0102] The connector 1 extends along a longitudinal axis X, is assembled to form a single object intended to transmit RF radiofrequency signals.

[0103] 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 line, 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.).

[0104] 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.

[0105] The coaxial line 2 comprises an external or ground contact 20 and a central contact 21 arranged inside the external 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.

[0106] 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.

[0107] 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.

[0108] As illustrated, the external contact 40 preferably comprises at its free end, two concentric rims 400, 401, one inside the other forming two staircase steps, and the external one extending radially outwards. inner concentric rim 401 allows the bearing surface of the outer contact 40 to be offset radially outwards with the mass of the PCB or the filter. The outer concentric rim 400 allows the bearing surface of the outer contact to be created 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.

[0109] As visible in 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.

[0110] 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 FIGS. 1A and 1B, this element in the form of an outer guide tube 5, preferably overmolded onto the outer contact 20, plays the role of mechanical structure of the connector. It therefore makes it possible both to stiffen this outer contact 20, by its base 50 which surrounds it, to protect all the outer contacts 20, 30, 40 and to confer mechanical robustness to the connector 1. Due to the significant axial travel of the outer contact 40, the guide tube 5 prevents the deviation of the outer contact 40, particularly when the latter is fully deployed.

[0111] 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.

[0112] The fully tubular shape of the element 5 makes it possible to reduce the overall size of the connector. But only its tubular inner surface is used for guidance, its outer shape being able to vary according to applications or needs.

[0113] 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.

[0114] The transition zones ZI 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 an impedance stable, typically equal to 50 ohms, regardless of the deployed position, i.e. sliding position of the coaxial lines of the connector. This allows the connector 1 according to the invention to operate above 12 GHz, preferably up to 20 GHz.

[0115] In the mode illustrated in figures 1 to 1B, the unitary coaxial connector 1 comprises:

[0116] - a first electrically conductive body 12, forming the external contact 20 of the coaxial line 2, the guide tube 5 being overmolded around it by its base portion 50;

[0117] - a second 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;

[0118] - a third 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;

[0119] - a fourth electrically conductive body 15 forming the central contact 41 of the coaxial line 4 sliding on the central contact 31 of coaxial line 3.

[0120] 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.

[0121] 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.

[0122] These helical springs can be replaced by any other suitable elastic return means (elastic washers, cut metal part, etc.).

[0123] [Fig. 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.

[0124] 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 using SMT technology. These legs 22 could also be arranged parallel to the X axis for through-hole soldering to the PCB, or press-fit mounting inside a hole in the PCB.

[0125] The body 12 also comprises at its base openings 23 making it possible to produce the guide tube 51 by overmolding on the body 12. Advantageously, this overmolding of the outer tube 5 also makes it possible to produce at the same time an electrical insulating block 51, as illustrated in FIGS. 1A and 1B, in which a smaller diameter part of the central contact 21 is mechanically retained. The openings 23 have the shape of oblong through holes. Other shapes are conceivable depending on the technical constraints of overmolding the tube, and where appropriate the electrical insulating block.

[0126] 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.

[0127] 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.

[0128] 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 external or ground contact 30 slides outside the external 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 external 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.

[0129] 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.

[0130] In certain configurations of a connector 1 coming into contact with a PCB or a filter, the edge 401 of the outer contact 40 and the end 410 of the central contact 41 may be significantly offset longitudinally. In other words, the rim 401 and the end 410 may not be coplanar.

[0131] 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 facing the filter, putting the elastic elements 6 and 7 into mechanical pre-stress.

[0132] 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.

[0133] The method of assembling the unitary coaxial connector 1 which has just been described comprises the following steps:

[0134] i / provision of the first electrically conductive body 12 forming the external contact 20 ([Fig.3]);

[0135] ii / provision of a second electrically conductive body 13 comprising two different diameters, respectively forming the external contact 30 and the external contact 40;

[0136] iii / mechanical assembly of a first connector subassembly 17 comprising a third electrically conductive body 14 having two different diameters, respectively forming the central contact 21 and the central contact 31, and a fourth electrically conductive body 15 forming the central contact 41, sliding on the central contact 31 ([Fig.4]). This step iii / preferably comprises the housing of 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;

[0137] iv / overmolding of the guide tube 5 on the first electrically conductive body so as to form a second connector subassembly 16 ([Fig.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;

[0138] or

[0139] iv' / overmolding of the guide tube 5 both on the first electrically conductive body 12 and on the central contact 21 of the coaxial line 21 of the first connector subassembly 17 so as to form a second connector subassembly;

[0140] vi / mechanical assembly of the second electrically conductive body 13 in the second subassembly 16 so that the external contact 30 slides on the external contact 20 and the guide tube 5 mechanically guides the external contact 40. Beforehand, the helical spring 6 is wound around the external contact 20 and comes into axial abutment, when the body 13 is inserted, on the one hand against a shoulder of the tube guide 5 and on the other hand against the shoulder forming the junction between the external contact 30 and the external contact 40.

[0141] Advantageously, the electrically conductive bodies are obtained by stamping.

[0142] Alternatively, step iv7 can be carried out with overmolding of the central electrical insulator 51.

[0143] [Fig. 6] illustrates 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.

[0144] 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.

[0145] 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.

[0146] 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.

[0147] The PCBs which must be connected to each other by one or more coaxial connectors 1 which have just been described can use fragile coatings which are not compatible with the bearing and friction forces of the coaxial connectors 1. These coatings, typically made of tin, allow cost savings.

[0148] 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 [Fig.7]. The interconnection plate 9 makes it possible to simplify the PCB and reduce its manufacturing cost.

[0149] 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 electrically concentric conductive tracks 910, 911 separated by an electrical insulator. These tracks 910, 911, intended to bear respectively with the external contact 40 and the central contact 41, may be made of a hard metal coating, typically nickel-gold alloy or silver, which is compatible with the pressure applied by a coaxial connector 1.

[0150] 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.

[0151] [Fig.8] shows a 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.

[0152] [Fig.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 [Fig.8].

[0153] Figures 10 and 11 show 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.

[0154] The third 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 external shoulder 210 in an internal shoulder of the sleeve 31, 21.

[0155] 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.

[0156] 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.

[0157] 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 tabs hooking 500 at its free end which hook onto a shoulder of the external contact 40.

[0158] 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 in all circumstances. The guide element 5 simultaneously ensures the electrical ground connection with the PCBL

[0159] 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.

[0160] The fourth 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. 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.

[0161] Thus, a unitary 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.

[0162] Other variants and improvements may be provided without departing from the scope of the invention.

Claims

Claims

1. Unitary coaxial connector (1), intended to transmit 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; - a guide element (5), 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.,

2. A unitary coaxial connector according to claim 1, the guide element being adapted to guide the larger diameter outer contact.

3. Unitary coaxial connector according to claim 1 or 2, 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.

4. A unitary coaxial connector according to claim 3 in combination with claim 2, the guide element being integral with the outer contact of smaller diameter.

5. A unitary coaxial connector according to claim 3 or 4, the guide element being overmolded around the external contact (20) of the coaxial line.

6. A unitary coaxial connector according to claim 5, the guide element being further overmolded to form an electrically insulating block.

7. 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 of the latter.

8. 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.

9. Unitary coaxial connector according to claim 8, comprising: - a first electrically conductive body (12), forming the external contact (20) of a first coaxial line, integral with the guide element, preferably by being overmolded with the latter; - a second electrically conductive body (13) having two different diameters, respectively forming the external contact (30) of a second coaxial line and the external contact (40) 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;- a third electrically conductive body (14) having at least two different diameters, respectively forming the central contact (21) of the first coaxial line and the central contact (31) of the second coaxial line; - a fourth electrically conductive body (15) forming the central contact (41) 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.;

10. Unitary coaxial connector according to claim 9, 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.

11. Unitary coaxial connector according to claim 10, the elastic return means consisting of a helical spring (6) wound around between the guide element and the outer contact (30) of smaller diameter of the second electrically conductive body and in axial abutment on the one hand against a shoulder of the guide tube and on the other hand against the shoulder forming an injunction between the outer contact of smaller diameter and that of larger diameter of the second body.

12. Unitary coaxial connector according to one of claims 9 to 11, 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.

13. Unitary coaxial connector according to claim 12, 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 third electrically conductive body and in axial abutment against the blind end (410) of a tube forming the central contact (41) of the fourth electrically conductive body.

14. Unitary coaxial connector according to claim 9 in combination with claim 10 or 11 and claim 12 or 13, wherein: - the guide element (5) is electrically conductive and integral with the external contact (20) formed by the first electrically conductive body; - the third 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 fourth electrically conductive body (15) forming the central contact (41) of the third coaxial line being slidably mounted relative to the second body electrically (13) conductor 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).

15. Unitary coaxial connector according to one of claims 9 to 14, 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).

16. Unitary coaxial connector according to one of the preceding claims, the guide element comprising centering and / or mechanical retention feet (53) adapted to position and / or preassemble, 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.

17. Unitary coaxial connector according to one of the preceding claims, with the exception of claim 14, 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.

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

19. A unitary coaxial connector according to one of the preceding claims, with the exception of claim 14, 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 permanent electrical and mechanical connection with a printed circuit board (PCB1).

20. 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 rims (400, 401), one inside the other forming two staircase steps, and the external one extending radially outwards.

21. Coaxial connection assembly (100), 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 (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) 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 (4) at the other longitudinal end (11) of the connector.

22. Multi-channel coaxial connection assembly (100) according to claim 21, comprising: - several coaxial connectors (1.1 to 1.8) arranged parallel to each other; - several interconnection plates (9.1 to 9.8) each intended to be connected to the other of the coaxial lines of each connector.

23. Method for producing a unitary coaxial connector according to one of claims 9 to 20, with the exception of claim 14 comprising the following steps: i / providing a first electrically conductive body forming the external contact of a first coaxial line; ii / providing a second 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 third 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 fourth 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 of the guide element on the first 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 first 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 second 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.;

24. Method according to claim 23, step iv / of overmolding being 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.

25. Method according to claim 23 or 24, the assembly step iii / being 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.

26. Method according to one of claims 23 to 25, the assembly step v / being 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.

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