WO2024050728A1

WO2024050728A1 - Connection assembly for multiple module-to-board (m2b) or module to module (m2m) connection including a plurality of unitary coaxial connection assemblies wherein the outer contact of one socket being integral part of module of m2b or m2m

Info

Publication number: WO2024050728A1
Application number: PCT/CN2022/117627
Authority: WO
Inventors: Shan QIN
Original assignee: Shanghai Radiall Electronics Co., Ltd.; Radiall Sa
Priority date: 2022-09-07
Filing date: 2022-09-07
Publication date: 2024-03-14

Abstract

A connection assembly for a multiple module-to-module (M2M) or a module-to-board (M2B) connection includes a plurality of unitary RF connection assemblies (1), and each unitary RF connection assembly (1) comprises at least one socket (6), wherein at least an outer contact (61) of the socket (6) of the unitary RF connection assembly (1) is an integral part of one component of one module of the module-to-module (M2M) or the module-to-board (M2B) connection.

Description

CONNECTION ASSEMBLY FOR MULTIPLE MODULE-TO-BOARD (M2B) OR MODULE TO MODULE (M2M) CONNECTION INCLUDING A PLURALITY OF UNITARY COAXIAL CONNECTION ASSEMBLIES WHEREIN THE OUTER CONTACT OF ONE SOCKET BEING INTEGRAL PART OF MODULE OF M2B OR M2M

Field of the invention

The present invention relates to a RF connection assembly including a plurality of unitary coaxial connection assemblies partially integrally formed with an electrical equipment box.

Such an assembly can be used in particular to link a printed circuit board (PCB) to another component such as a module or a filter or a power amplifier or an antenna (Module to Board M2B applications) or even to link together two of these components (Module to module M2M applications) .

The invention applies, for example, to a connection used to link boards inside RRU/RRH (remote radio unit/remote radio head) transmitter modules for the wireless communications market.

The invention also relates generally to the connection in the medical domain, the aeronautical or transport domain, the space domain or even the telecommunications domain.

By “RF connector” , it is to be understood a connector able to transmit signals from the Direct Current (DC) range to the radiofrequency (RF) range, including the hyper frequency (HF) range, the signals being high speed digital signals (HSDL for High-Speed Data Link) or radiofrequency (RF) signals.

Background of the invention

With the continuous development of wireless communication technology, board to board connectors are becoming more and more widely used in wireless system module interconnection, such as communication base station, RRH, repeater, GPS devices, and other similar applications. Three major trends of wireless devices are smaller dimensions, lower cost, and easier installation. For a board-to-board connection, the market also requires them to be smaller, cheaper, and more modularized.

There are already on the market and in the prior art examples of connection assemblies dedicated to the telecommunications sector for cellular radiotelephony infrastructures. In fact, the trend in this market is to minimize the losses of the RF (radiofrequency) part to reduce the amplifying elements of the base stations. For this, on the one hand, the actual radio part of the stations is being increasingly relocated as close as possible to the transmission-reception antennas, in the RRU/RRH transmitter modules, and on the other hand, the RF leads internal to the radio unit are being replaced by direct interconnections.

So-called board-to-board connections have thus been developed according to the successive generations of the last decade.

A first generation of connection assemblies is thus known, for directly interconnecting boards, for example marketed under the names SMP, SMP-Com, MMBX from Radiall with limited axial misalignment to a few tenths of a millimetre, of the order of 0.3 mm to 0.6 mm. SMP series are standardized in accordance with MIL STD 348 specifications, the DESC specifications 94007 & 94008A second generation of connection assemblies is also known, with bigger axial misalignment from 2mm to 2.4mm, for example marketed under the names SMP-MAX by the company Radiall or else marketed under the names MBX by the company Huber and Suhner or else marketed under the name AFI by the company Amphenol RF, or else marketed under the name Long Wipe SMP and P-SMP by the company Rosenberger.

Although there are different degrees of axial misalignment between two generations, the working principle for radial misalignment and connection is the same for two generations. Such connection assemblies respectively consist of a first socket of snap-fitting (or “snap” ) type, a second socket of “sliding” (or smooth bore) type with a guiding cone ( “slide on receptacle” ) , and a connection coupling called adapter (or bullet) , with the first and second sockets respectively fastened to the ends thereof. The connection is therefore made blind by the re-centring of the connection coupling by means of the guiding cone of the sliding socket. The radial misalignment is obtained by a rotation of the coupling in the groove of the snap-fitting socket. The first and second sockets are conventionally made of brass and have no elastic functions. The connection coupling is typically made of an expensive noble elastic metallic material, for example CuBe2 or CuSn4Pb4Zn4, and provided at each of its ends with elastic means (petals and slots for example) that cooperate with the first and second sockets.

Thus, the three-part structure of snapping socket-adapter-sliding socket is widely used in the connection design of board-to-board connections, namely a board-to-RF module or a RF module-to-RF module interconnection. It can be referred for example to WO2010/010524, WO2013/150059, CN110391517 patent applications which each describes a connection assembly with a three-part structure, i.e., comprising three independent sub-assemblies.

Figure 1 shows a RF coaxial connection assembly 1 having such a three-part structure in a coupled configuration, with a sliding end socket 2, a snapping end socket 3 and an adapter 4 as the connection coupling between the two

sockets

2, 3.

The sliding-end socket 2 includes a central contact 20, an outer contact 21 being coaxially disposed around the central contact 20, and an electrical insulating body 22 being interposed and held between the central conductor 20 and the outer conductor 21.

The snapping end socket 3 includes a central contact 30, an outer contact 31 being coaxially disposed around the central contact 30, and a solid electrical insulating body 32 being interposed and held between the central conductor 30 and the outer conductor 31.

The adaptor 4 includes a central contact 40, an outer contact 41 being coaxially disposed around the central contact 40, and two electrical

insulating bodies

42, 43 being each interposed and held between the central conductor 40 and the outer conductor 41 and arranged at one end of the adapter 4.

Each end of the outer contact 41 is slotted and delimits spring tongues which are formed by slots. These spring tongues are functionally separated from each other in the circumferential direction and elastically move in the radial direction. Each tongue includes

lateral protrusions

410, 411, that protrude outward the adapter 4. In the coupling configuration, the protrusions 410 are radially in contact with the cylindrical surface 210 of the outer contact 21 thanks to the elasticity of the spring tongues and can be sliding floating mounted in order to provide the axial misalignment to compensate for the tolerance from the manufacture and assembly of related components in the equipment. The maximum sliding distance A is shown on figure 1. The protrusions 411 are accommodated in the groove 310 achieved inside the recess of the outer contact and radially contact the surface of the groove thanks to the elasticity of the spring tongues 411. These connections rely on the deflection of the adapter on the snap-fitting end and on the sliding end to achieve a radial tolerance of connection. Moreover, the arc-shaped surface of the

protrusion

410, 411 and the elasticity of the spring tongues can achieve a reliable contact, especially in the case of radial deviation, and a large radial deviation amount can be satisfied.

Thanks to the

spring protrusions

410, 411, the mechanical connection of this three-part structure allows the adapter 4 in the lateral direction with respect to the socket 3 to tilt a certain deviation angle. As explained previously, the mechanical connection is generally configured as a detachable snap connection and makes it possible to separate the adapter 4 from the socket 3 by applying a certain force in the axial direction.

As shown, the socket 3 can be soldered to a PCB, notably by legs of the outer contact 31 dedicated to that.

Also, on the other side of the mechanical connection, the body of the socket 2 can be screwed or pressed to another RF module 5, notably by soldering the central contact 20 to the central contact 50 of the module 5. As shown, the RF module 5 has a conductive body 51 and may include a conductive lid 52 arranged on the surface of the body 51, this lid 52 being necessary when the RF module 5 is configured as a filter in RRU.

Figures 2A to 2C show the steps of assembly the end socket 2 with an RF module having a central contact 50.

The end socket 2 is an independent sub-assembly with its three assembled elements, namely the central contact 20 around which is arranged the coaxial outer contact 21, the electrical insulating body 22 being held between them. This independent sub-assembly 2 is assembled in the conductive body 51 of the RF module 5 (figure 2A) .

Then, a central contact 50 as a pin is mounted with socket 2 to be connected with the central contact 20 of the end socket 2, along the central axis of the end socket 2 (figure 2B) .

And the central contact 50 is soldered to the central contact 20 by a weld line S (figure 2C) . When the module 5 is configured as a filter, a lid 52 is arranged on the top of the conductive body 51 by surrounding the outer contact 21.

Also in a filter configuration, instead of a central contact 50 as a pin, a conductive strip 53 which extends transversally to the central contact 20 is brought into contact with this latter (figure 2E) .

And the conductive strip 53 is soldered to the central contact 20 by a weld line S (figure 2E) .

The central contact of figure 2D is mounted similarly as in figure 2E. But the outer contact is of the snap type in figure 2D.

However, because of the three-part structure with three independent components, namely an adapter and two end sockets, the whole connection assembly may be costly. The cost is all the higher as a board-to-module or module-to-module connection requires many independent coaxial assemblies.

Moreover, in the high-speed data transmission service of a base station for example, the need for independent coaxial connections increases drastically, from 2 to 4 connections today up to 64 connections or more. And if the cost of producing these multiple connections is relatively high, it thus constitutes a brake for the market.

Therefore, it exists the need to improve the solutions dedicated to module-to-module (M2M) or module-to-board (M2B) connections, notably to decrease the cost of achievement.

The invention aims to address all or part of these needs.

Summary of the invention

Thus, the subject of the invention, according to one of its aspects, is a connection assembly for a multiple module to board (M2B) or module to module (M2M) connection, including a plurality of unitary RF connection assemblies each comprising at least one socket.

According to the invention, at least the outer contact of one socket of a unitary RF connection assembly is an integral part of one component of the module of the board or module to module connection.

By “an integral part” , it should be understood that at least the outer contact of the socket and at least a component of the module are made in one piece. In other words, the function of the part of the socket is integrally achieved by the component of the board or of the module with continuity of material.

The outer contact is preferably an integral part of either the conductive body of the module or the lid of the module configured as a filter.

According to an advantageous variant, the outer contact is adapted to allow slide or snap-fitting of the adapter.

According to a first configuration, the central contact of the socket is an integral part of the central contact of the RF module.

According to a second configuration, the central contact of the socket is soldered to a conductive strip arranged inside the conductive body of the RF module.

According to an advantageous embodiment, each unitary RF connection assembly comprises further an independent socket to be linked to the other module of the M2M or M2B connection and an independent adapter intended to couple the two sockets mechanically and electrically.

According to another embodiment, each unitary RF connection assembly includes a coaxial connector intended to be mechanically and electrically coupled to the socket, comprising at least a flexible part configured to compensate radial and/or axial misalignment between the two modules of a M2M connection or between the module and a board of a M2B connection.

According to this another embodiment, the coaxial connector may be according to patent application PCT/CN2021/084138 or to patent application CN111146617. Thus, the coaxial connector of longitudinal axis, intended to be mechanically and electrically coupled to the socket comprises:

- a central contact extending along a longitudinal axis and,

- an outer contact,

- at least one electrical insulating solid body coaxially interposed between the central contact and the outer contact, the body being mechanically retained in the outer contact and mechanically retaining the central contact.

According to this embodiment and to an advantageous variant, the coaxial connector comprises:

- a central contact comprising two rigid portions each extending along a longitudinal axis and a flexible portion between the two rigid portions and,

- an outer contact comprising two rigid portions and a flexible portion between the two rigid portions,

- two electrical insulating solid bodies coaxially interposed between the central contact and the outer contact, one of the two bodies being mechanically retained in one of the two rigid portions of the outer contact and mechanically retaining one of the two rigid portions of the central contact, whereas the other of the two bodies is mechanically retained in the other of the two rigid portions of the outer contact and mechanically retains the other of the two rigid portions of the central contact,

wherein the ends of the two insulating bodies which are face-to-face, and the flexible portions are configured to allow a ball joint link in flexion around an axis perpendicular to the longitudinal axis.

Another subject of the invention relates to a process for manufacturing a connection assembly for a multiple module to board (M2B) or module to module (M2M) connection, including a plurality of unitary RF connection assemblies comprising at least one socket, wherein producing in a unique piece at least the outer contact of one socket of a unitary RF connection assembly and one component of the module of the M2B or M2M connection.

Advantageously, producing in a unique piece is achieved by a technique chosen among deep drawing, die-casting, machining, additive manufacturing.

Another subject of the invention concerns the use of the connector assembly such as described previously to transmit RF (radiofrequency) signals or HSDL (High Speed Data Link) signals.

In other words, the invention consists in a new sub-assembly with at least a piece which incorporates at least the traditional function of a component of a board or a RF module and one of the functions of a socket which was previously achieved by an independent sub-assembly of the socket.

Compared to the known three-part structure for board-to-board connections, the according to the invention allows to reduce the cost because at least one part of the structure is directly integrated into the structure of a RF module. And this reproduced for all the unitary connectors sub-assemblies.

The main advantages obtained by the connector according to the invention are numerous and can be itemized as follows:

- the costs for realizing the unitary connectors are very reduced compared to the three-part connection structure according to the prior art;

- the integration of at least one part in a RF module does not change the connection mode and performances of the three-part structure according to the prior art. Notably, with a connection assembly according to the invention, it is possible to achieve a transmission of high-speed digital signals (HSDL for High-Speed Data Link) or of radiofrequency (RF) signals;

- no need to manufacture and to assemble each outer contact of a socket which is directly integrated in a housing into the conductive body of the radio frequency module, or into its lid which is necessary when the module is configured as a filter of RRU;

- in some configurations, the central contact under the form of a pin of the socket and the central contact under the form of a pin of the radio frequency module is a unique piece.

- With the integration of the outer contact of socket, the processing cost of the RF module does not increase or only slightly increases, but the cost is greatly reduced in the following aspects:

● to eliminate a separate outer contact;

● it is no longer necessary to mount the independent components into the body of the RF module by means of threading or knurling according to the prior art, which saves the assembly cost and completely avoids some risks that may arise due to the fit, such as loose connection, metal chips caused by interference, and assembly is skewed, etc.

● when the pin of the socket and the pin of the RF module are integrated in a one-piece, there is no longer needed to weld these components when separated according to the prior art, which reduces the assembly cost, and completely avoids the risks caused by welding, such as softening of the insulating body of the socket caused by heating and skewing of the pin of the socket. There is also a reduction in the overall pin machining cost;

● no need to plate the part (s) of the socket which are integrated into the RF module. The outer contact and advantageously the pin (central contact) of the socket no longer need to be plated separately after integration, so the cost of plating is also reduced.

Moreover, the counterparts of the RF links, i.e., bullet and counterpart receptacle of SMP series for example, remain unchanged, which is an advantage for the standardization of the RF link.

According to another aspect, the invention concerns the use of the unitary RF connector described above or a connection module described above, to transmit RF (radiofrequency) signals or HSDL (High Speed Data Link) signals.

Brief description of the drawings

Other advantages and features of the invention will become more apparent upon reading the detailed description of exemplary implementations of the invention, given by way of non-limiting illustration, and with reference to the following figures, in which:

- Figure 1 is a longitudinal cross-section view of a three-part coaxial connexion assembly according to the prior art, with an end socket inserted in and attached to a RF module configured as a filter;

- Figure 2A to 2C are longitudinal cross-section views showing the different steps of mounting and soldering of an end socket of a three-part coaxial assembly according to the prior art to a RF module configured as a filter according to the prior art;

- Figure 2D and 2E are longitudinal cross-section showing the different steps of mounting and soldering of an end socket of a three-part coaxial assembly according to the prior art to a RF module configured as a filter according to a variant to the prior art;

- Figure 3 is a cross-longitudinal view of an end socket which outer contact is made integral with the conductive body of a RF module configured as a filter according to invention;

- Figure 4 is a cross-longitudinal view of a variant of Figure 3;

- Figure 5 is a cross-longitudinal view of an end socket which outer contact is made integral with the lid of a RF module configured as a filter according to invention;

- Figure 6 is a cross-longitudinal view of a variant of Figure 5 with an end socket in the snap configuration;

- Figure 7 is a side view of a connection assembly comprising a plurality of unitary end sockets which outer contact is made integral with the unique lid of a RF module configured as a filter;

- Figure 7A is a cross-longitudinal view of the connection assembly of Figure 7;

- Figure 8 is a top view the unique lid including the plurality of outer contacts of the end sockets according to Figures 7 and 7A;

- Figure 9 is a cross-longitudinal view of an end socket whose outer contact is made integral with the lid of a RF module configured as a filter according to a variant of the invention.

Detailed description

Throughout this application, the terms “interior” and “exterior” are to be understood in relation to a unitary connection assembly according to the invention.

For the sake of clarity, the same numerical reference is used for the same element of an electrical connection assembly according to the state of the art and of an electrical connection assembly according to the invention.

Figures 1 to 2E have already been described in detail in the preamble. They will therefore not be commented on hereafter.

According to the invention, a main structure of an RF module is used to integrate at least the outer contact 21 function of the socket 2 according to Figures 1 to 2E.

Figure 3 shows a first embodiment of a part of a RF module 6 whose body 61 serves as an outer contact with the sliding and guidance function of the three-structure part. This outer contact 61 surrounds coaxially a pin 60 as a central contact. An electrical insulating body 62 which is rigid is interposed between the pin 60 and the outer contact 61. The outer contact 61 is also a centring end piece comprising a centring surface which is of annular shape and of circular section, preferably frusto-conical, as shown. A metal strip 63 forming a central contact of the RF module has to be welded to the pin 60. A lid 52 can be attached to the body 61 as made in the prior art.

Figure 4 shows a second embodiment of a part of a RF module 6 whose body 61 serves as an outer contact with the sliding and guidance function of the three-structure part. This outer contact 61 surrounds coaxially a pin 60 as a central contact. An electrical insulating body 62 which is rigid is interposed between the pin 60 and the outer contact 61. The outer contact 61 is also a centring end piece comprising a centring surface which is of annular shape and of circular section, preferably frusto-conical, as shown. A lid 52 can be attached to the body 61 as made in the prior art. Here, the central pin 60 is a unique piece inside the body and the outer contact portions 61. This embodiment allows a better coaxiality between the pin 60 and the outer contact 61 compared to the prior art connection where the pin 50 of the RF module 5 has to be soldered to the pin 20 of a socket 2.

Figure 5 shows a third embodiment of a part of a RF module 6 whose lid 61 serves as an outer contact in the sliding configuration. This outer contact 61 surrounds coaxially a pin 60 as a central contact. An electrical insulating body 62 which is rigid is interposed between the pin 60 and the outer contact 61. The outer contact 61 is also a centring end piece comprising a centring surface which is of annular shape and of circular section, preferably frusto-conical 610, as shown, which can be shaped as a big protuberance in front of the plane surface of the lid 61. A metal strip 63 forming a central contact of the RF module has to be welded to the pin 60. The lid 61 can be attached to the body 64 as made in the prior art.

Figure 6 shows a fourth embodiment of a part of a RF module 6 whose lid 61 serves as an outer contact in a snap configuration. This outer contact 61 surrounds coaxially a pin 60 as a central contact. An electrical insulating body 62 which is rigid is interposed between the pin 60 and the outer contact 61. In this configuration, the elastic protrusions 410 are accommodated in the groove 611 inside the outer contact in the recess 612. They radially contact the cylindrical surface of the groove 611 and ensure the electrical link for any radial tolerance of misalignment. These connections rely on the deflection of the adapter on the snap-fitting end and on the sliding end (not shown) to achieve a radial tolerance of alignment.

A metal strip 63 forming a central contact of the RF module has to be welded to the pin 60. The lid 61 can be attached to the body 64 as made in the prior art. Compared to the embodiments of Figures 3 and 4, the embodiment of Figure 6 which makes integral the outer contact with the lid 61 instead of the body of the RF module allows easy manufacturing of a snap configuration. Thus, the inner groove 611 whose function is to accommodate spring protrusions, such protrusions 411 of an adapter 4 shown on Figure 9, is easy to manufacture directly into the lid.

The snap and the sliding functions remain the same as the prior art.

Figures 7 and 7A show a whole connection assembly for a multiple connection with a unique outer contact 61 integral with the lid of the RF module according to the invention. In this connection assembly, the lid 61 with the integration of a plurality of outer contacts 61 is common for the plurality of unitary RF connection assemblies 1 each comprising two

sockets

6, 3 and an adapter 4 intended to mechanically and electrically couple the two

sockets

6, 3. Each of the snapping end socket 3 and adapter 4 are the same as the ones in the three-structure part such as shown on Figure 1.

The plurality of outer contacts can be either of snap type or sliding type or a combination of them.

Figure 8 shows an example of one regular distribution of the frustoconical shapes 610 of the external contacts 61 on the flat surface of the lid. The distribution is made with a pitch P which is of 12mm for example. But these are depending on the equipment.

Figure 9 shows a variant of a snap configuration made into the lid 61 according to the inner groove 611 such as shown on Figure 6, which accommodates the spring protrusion 411.

Other variants and enhancements can be provided without in any way departing from the framework of the invention.

For example, if the illustrated embodiments show a RF module, any kind of known receptacles on module could be integrated, like of the SMP, SMP-MAX series. Another example is the receptacle described in the application PCT/CN2021/084138.

The expression “comprising a” should be understood to be synonymous with “comprising at least one” , unless otherwise specified.

Claims

A connection assembly for a multiple Module-to-module (M2M) or a Module-to-Board (M2B) connection, including a plurality of unitary RF connection assemblies (1) each comprising at least one socket (6) , wherein at least the outer contact (61) of one socket (6) of a unitary RF connection assembly (1) is an integral part of one component of one module of the M2M or M2B connection.
A connection assembly according to Claim 1, wherein the outer contact is an integral part of the conductive body of the module.
A connection assembly according to Claim 1, wherein the outer contact is an integral part of the lid of the module.
A connection assembly according to Claim 1 to Claim 3, wherein the outer contact is adapted to allow slide or snap-fitting of the adapter (4) .
The connection assembly according to anyone of the preceding claims, wherein the central contact of the socket is an integral part of the central contact of the RF module.
A connection assembly according to anyone of the preceding claims, wherein the central contact of the socket is assembled with electrical conduction to a conductive strip arranged inside the conductive body of the RF module.
A connection assembly according to anyone of the preceding claims, each unitary RF connection assembly (1) comprising further an independent socket (3) to be linked to the other module of the M2M or M2B connection and an independent adapter (4) intended to couple the two sockets mechanically and electrically.
A connection assembly according to anyone of claims 1 to 6, each unitary RF connection assembly (1) comprising further a coaxial connector of longitudinal axis, intended to be mechanically and electrically coupled to the socket (6) comprising:

- a central contact extending along a longitudinal axis and,

- an outer contact,

- at least one electrical insulating solid body coaxially interposed between the central contact and the outer contact, the body being mechanically retained in the outer contact and mechanically retaining the central contact.
A process for manufacturing a connection assembly for a multiple module to board (M2B) or module to module (M2M) connection, including a plurality of unitary RF connection assemblies (1) comprising at least one socket (6) , wherein producing in a unique piece at least the outer contacts (61) of one socket (6) of a unitary RF connection assembly (1) and one component of the module of the M2Bor M2M connection.
A process according to Claim 9, wherein producing in a unique piece is achieved by a technique chosen among deep drawing, die-casting, machining, additive manufacturing.
Use of the connector assembly according to claims 1 to 8 to transmit RF (radiofrequency) signals or HSDL (High Speed Data Link) signals.