WO2024258323A1

Movatterモバイル変換

Info

Publication number: WO2024258323A1
Application number: PCT/SE2023/050595
Authority: WO
Inventors: Jinglei Zhang; Hong Tang; Fan Yang; Thomas Andersson; Niclas HALLQWIST; Magnus Johansson
Original assignee: Telefonaktiebolaget LM Ericsson AB
Current assignee: Telefonaktiebolaget LM Ericsson AB
Priority date: 2023-06-14
Filing date: 2023-06-14
Publication date: 2024-12-19
Anticipated expiration: 2025-12-14

Abstract

A connecting structure (300) for connecting two or more circuit boards (PCB1, PCB2) is disclosed. The connecting structure (300) comprises at least two conductive contacts (311, 312), one conductive contact (311) for signal path and one conductive contact (312) for signal return path. The connecting structure (300) further comprises an insulating body (320) and a conductive elastic frame (330). The at least two conductive contacts (311, 312) are mounted, non-coaxially side by side with a predefined distance between the at least two conductive contacts (310), on the insulating body (320). The insulating body (320) is surrounded by the conductive elastic frame (330).

Description

CONNECTING STRUCTURE FOR CIRCUIT BOARDS

TECHNICAL FIELD

Embodiments herein relate to connecting structure for circuit boards. In particular, the embodiments relate to connecting structure for connecting two or more circuit boards and method for manufacturing the connecting structure.

BACKGROUND

In wireless communication equipment such as Remote Radio Unit (RRU), Active Antenna System (AAS), the major trends are smaller size, lower cost, and easier installation. There’re many board-to-board connections between radio boards, power amplifiers (PA), antenna boards etc. in the wireless communication equipment. The board-to-board connections need to be as close as possible and board-to-board radio frequency (RF) connectors have been developed accordingly. Board-to-board RF connectors also need to be smaller, cheaper, and more modularized. Meanwhile, frequency ranges are wider and isolation requirements are higher for board-to-board RF connectors.

For example, in the RF connections between PA and radio board, there’re transmitter signals, receiver signals, and transmitter observation receiver signals. These signals must be isolated from each other, and the isolation requirements may be very tough up to e.g. 80dB.

In the current market, the main solution for board-to-board RF connectors is a 3-piece solution, i.e. one bullet or adaptor connected with 2 board connectors, as shown in Figure 1. Connected Supplier https://connectorsupplier.com/how-to-specify-coaxial-blind-mate- connectors/ retrieved on 13^th June 2023.

Such 3-piece connection assembly consists of one connector 111 of snap-fitting or snap type, and another connector 112 of sliding or smooth bore type with a guiding cone i.e. sliding on receptacle, and a connection coupling called adaptor or bullet 113. The mechanical design can cope with mechanical misalignment in radial and axial directions and still hold electrical performance. The 3-piece connector shown in Figure 1 is a coaxial structure which means that the contactors for signal and return paths are arranged in coaxial.

The common 3-piece solutions have good RF performance. However, all the connectors and bullets take more footprint on circuit board, e.g. bigger than 6mm x 6mm, and higher mating height e.g. larger than 10mm. The common 3-piece solutions also have a limited frequency range e.g. only up to 6GHz.

The coupling of 3 pieces is easily damaged when the bullets slide into socket. Furthermore, it also takes time for massive productions. There’re also 2-piece or 1 -piece solutions in the market recently, as shown in Figure 2. The 2-piece or 1 -piece solution has a center pin 210 for signal path and a mechanical structure 220 surrounding the center pin as return path. So the 2-piece or 1 -piece solution is still within a traditional coaxial structure. The 2-piece or 1 -piece solution can reduce mating height, however it needs bigger space for center pin and return path. The 2-piece or 1 -piece solution may simplify installation, but have limited applications to achieve good RF performance, due to return path design and keep desired 50 Ohm. The 2-piece or 1 -piece solutions are still on developing and not widely used, still have risk on unstable signal path, reliability of additional outer contact body, and stuck risk for center pin 210 with weak spring structure 230.

All those configurations of the 3-piece, 2-piece or 1 -piece connections do not make it possible to obtain a sufficiently great radial and/or axial misalignment in very short mating height, e.g. less than 5mm. The cost of producing these connections is relatively high, thus constituting a brake for new generation radio modules in the wireless communication equipment.

SUMMARY

It is therefore an object of embodiments herein to provide a board-to-board radio frequency (RF) connections with improvements on e.g. cost, mating height, installation, maintenance, size and footprint, misalignment tolerance, RF performances, isolation, standardization and modularization etc.

According to one aspect of embodiments herein, the object is achieved by a connecting structure for connecting two or more circuit boards. The connecting structure comprises at least two conductive contacts, one conductive contact for signal path and one conductive contact for signal return path. The connecting structure further comprises an insulating body and a conductive elastic frame. The at least two conductive contacts are mounted, non- coaxially side by side with a predefined distance between the at least two conductive contacts, on the insulating body. The insulating body and at least two conductive contacts are surrounded by the conductive elastic frame. Herein is achieved a non-coaxial structure for board-to-board connections.

According to some embodiments herein, the conductive contact may comprise an elastic body configured to have longitudinal and transverse flexibility.

According to some embodiments herein, the elastic body may comprise a contact section, a transition section and a supporting section which are configured to be flexible or movable in longitudinal and transverse direction. According to some embodiments herein, the conductive contact may further comprise a fixture section configured to be inserted in the insulating body, and a soldering ball configured to be soldered on a connection contact of a circuit board.

According to some embodiments herein, the conductive contact may have a shape depends on required mating height, compression range and total electrical compliance length.

According to some embodiments herein, the conductive contact may have any one of a C-shape, an arc-shape, a 7-shape, a Z-shape.

According to some embodiments herein, the soldering ball may be configured to be soldered on a connection contact of a first circuit board. When a pressure force from a complementary connection contact of a second circuit board is applied on the contact section of the conductive contact, the conductive contact is able to flex toward one of the faces of the insulating body.

According to some embodiments herein, the conductive contact may be made of elastic metal material e.g. copper alloy.

According to some embodiments herein, the connecting structure may be configured to connect two circuit boards with a distance less than 5 millimetre between the two circuit boards.

According to some embodiments herein, the predefined distance between two conductive contacts may be 2mm or less than 2mm.

According to some embodiments herein, the connecting structure may comprise more than two conductive contacts mounted on the insulating body in a single-ended signal pattern or a differential signal pattern.

According to some embodiments herein, the insulting body may comprise a guiding structure for parallel misalignment between two circuit boards.

According to some embodiments herein, the insulting body may comprise at least one protrude structure to prevent the over bent of the conductive contact.

According to some embodiments herein, the conductive elastic frame may be a customized conductive elastomer gasket designed and optimized for a desired conductivity and a desired compress range.

According to some embodiments herein, the conductive elastic frame may be configured to be soldered on a circuit board.

According to one aspect of embodiments herein, the object is achieved by a method for manufacturing a connecting structure. The method comprises forming at least two conductive contacts with elastic metal material, one conductive contact for signal path and one conductive contact for signal return path, mounting the at least two conductive contacts, non-coaxially side by side with a predefined distance between the at least two conductive contacts, on an insulating body by inserting a portion of the conductive contact into the insulating body, and mounting a conductive elastic frame surround the at least two conductive contacts and insulating body.

According to some embodiments herein, the at least two conductive contacts may be formed by stamped forming copper alloy.

In other words, embodiments herein provide an improved RF connector with noncoaxial structure. The connecting structure according to embodiments herein comprises at least two elastic conductive contacts, which can be retained in an insulting body for assembly and surrounded by a conductive elastic frame to prevent signal leakage and achieve extremely high isolation between signals no matter how close those RF signal transmissions. The conductive elastic frame may be tailored to fit a range of RF connection ecosystems while using the low-profile conductive contacts for connecting two circuit boards with short distance e.g. mating height may be less than 5 mm.

The connecting structure according to embodiments herein is a complete RF solution for high frequency range, e.g. up to 15 GHz.

The elastic conductive contacts, insulting body and conductive elastic frame are assembled as a complete connector, installed for short distance board-to-board RF connections. The connecting structure according to embodiments herein may be applied for larger tolerance range between two circuit boards.

The conductive contacts designed for electrical signal transmission are provided with an elastic body which can be deformed to make sure well contact with circuit boards. All conductive contacts have longitudinal and transverse flexibility, larger tolerance capability during signal transmission, can meet tough misalignment tolerance requirements on real products application.

The conductive contacts are retained in an insulting body as a connector in traditional sense. The conductive contacts are placed in line, can be arranged and optimized by simulations, which make it convenient for production and assembly with simple structure and easy manufacturing technology and can achieve very small pitches and high density.

The insulting body may be designed with guiding feature for parallel misalignment between two circuit boards.

The insulting body may have several protrude structures e.g. stoppers or pillars, to prevent the over bent of conductive contacts and to be suitable for wider tolerance range.

The connecting structure according to embodiments herein is friendly to circuit board plating, layout, soldering, and installation in radio units or modules. The connecting structure according to embodiments herein has very low cost due to adopting to continuous high-speed stamping process and assembly process.

Therefore, embodiments herein provide a high-quality RF connector between two circuit boards with regard to e.g. cost, mating height, installation, maintenance, size and footprint, misalignment tolerance, RF performances, isolation, standardization and modularization etc.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of embodiments herein are described in more detail with reference to attached drawings in which:

Figure 1 is a schematic cross-section view of an example 3-piece radio frequency (RF) connector connected to two circuit boards;

Figure 2 is a schematic cross-section view of an example 2-piece or 1 -piece RF connector; Figure 3 (a) is a schematic perspective view of a connecting structure in relation to two circuit boards according to an example embodiment herein, and (b) is a schematic top view of the connecting structure shown in (a);

Figure 4 are schematic diagrams showing different placement patterns of conductive contacts according to embodiments herein;

Figure 5 is a schematic perspective view of an example conductive contact according to embodiments herein;

Figure 6 is a schematic perspective view of an example connecting structure according to embodiments herein;

Figure 7 is a schematic perspective view of an example conductive elastic frame according to embodiments herein;

Figure 8 is a schematic perspective view of an example application using the connecting structure according to embodiments herein;

Figure 9 is a schematic cross section view of an example of board-to-board connection using the connecting structure according to embodiments herein;

Figure 10 is a flow chart illustrating a method for manufacturing a connecting structure according to embodiments herein; and

Figure 11 is a schematic diagram illustrating an electronic apparatus in which a connecting structure according to embodiments herein may be used. DETAILED DESCRIPTION

Figure 3 (a) shows a schematic cross-section view of an example connecting structure 300 for connecting two or more circuit boards PCB1 , PCB2.

The connecting structure 300 comprises at least two conductive contacts 311 , 312. One conductive contact 311 is for signal path and one conductive contact 312 is for signal return path.

The connecting structure 300 further comprises an insulating body 320 and a conductive elastic frame 330.

The at least two conductive contacts 311 , 312 are mounted on the insulating body 320. The insulating body 320 and the at least two conductive contacts 311 , 312 are surrounded by the conductive elastic frame 330 to prevent signal leakage and achieve extremely high isolation between different radio frequency (RF) signals.

As can be seen from Figure 3, the connecting structure 300 is a non-coaxial structure, where the at least two conductive contacts 311 , 312 are placed non-coaxially side by side on the insulating body 320. The distance d between the at least two conductive contacts 311 , 312 may be predefined according to applications. The predefined distance d between two conductive contacts 311 , 312 may be e.g. 2mm or less than 2mm. In an embodiment the predefined distance may be determined by Signal Integrity (SI) simulations, and/or SI tools.

The at least two conductive contacts 311 , 312 retained in the insulating body 320 for assembly and surrounded by the conductive elastic frame 330. The conductive contacts 311 , 312, the insulating body 320 and the conductive elastic frame 330 are assembled as a complete RF connector. When the conductive contacts are installed between two boards with special elastic design, that will make the field similar to the classic coaxial RF structure to have good RF performance.

The quantity of elastic conductive contacts may vary according to requirements on the amount of single-ended and differential signals. That is, the connecting structure 300 may comprise more than two conductive contacts mounted on the insulating body 320 in a single-ended signal pattern or a differential signal pattern. The placement of conductive contacts can be optimized to be very high density and the pitches between the conductive contacts may be e.g. 2mm or less than 2mm. Figure 4 are schematic diagrams showing different placement patterns of conductive contacts according to embodiment herein. The conductive contacts are inserted in the insulting body with optimized pattern as shown in Figure 4. Figure 4 (a) is a single-ended signal pattern 411 with one contactor for RF signal indicated by “S” and one contactor for return signal indicated by “R”. Figure 4 (b) is a single-ended signal pattern 412 with one contactor for RF signal indicated by “S” and two contactors for return signal indicated by “R”. Figure 4 (c) is a differential signal pattern 413 with one contactor for positive RF signal indicated by “+” and one contactor for negative RF signal indicated by Figure 4 (d) is a differential signal pattern 414 with one contactor for positive RF signal indicated

one contactor for negative RF signal indicated

and two contactors for return signal indicated by “R”. Figure 4 (e) is a differential signal pattern 415 with one contactor for positive RF signal indicated by

one contactor for negative RF signal indicated by

and three contactors for return signal indicated by “R”.

At least one contactor for RF signal and one contactor for signal return within short distance can make the field similar as classic coaxial structure, to achieve good RF performance.

According to embodiments herein, the conductive contacts 311 , 312 have longitudinal and transverse flexibility, larger tolerance capability during signal transmission, to meet tough misalignment tolerance requirements on real products applications. In order to achieve this, the conductive contacts 311 , 312 are provided with an elastic body which can be deformed to make sure well contact with circuit boards.

Figure 5 is a schematic perspective view of an example conductive contact 500 according to embodiments herein to show the detailed structure of the conductive contacts 311 , 312.

One end of the conductive contact 500 may be a soldering ball of a ball grid array (BGA) type and surface mounted on a circuit board, which can be very small footprint, and good for production and quality control. The other end of the conductive contact 500 can be bent or deformed with high flexibility. When the conductive contacts 311 , 312, 500 are pressed by a circuit board during installation, the conductive contacts will deform in a longitudinal direction meanwhile transverse elastic displacement along.

Therefore, according to some embodiments herein, the conductive contact 311 , 312 500 may comprise an elastic body 510 configured to have longitudinal and transverse flexibility. The elastic body 510 may be configured to be flexible or movable in longitudinal and transverse direction. The elastic body 510 may comprises a contact section 511 , a transition section 512 and a supporting section 513. The conductive contact 500 may further comprise a fixture section 514 configured to be inserted in the insulating body 320, and a soldering ball 515. The soldering ball 515 may be configured to be soldered on a connection contact of a circuit board, e.g. a first circuit board PCB1. When a pressure force from a complementary connection contact of a second circuit board PCB2 is applied on the contact section 511 of the conductive contact 311 , 312, 500, the conductive contact 311 , 312, 500 is able to flex toward one of the faces of the insulating body 320.

The conductive contact 311 , 312, 500 may have any kind of shape. The shape of the conductive contact 311 , 312, 500 depends on a required mating height, compression range and I or total electrical compliance length. The electrical compliance length is the current travel length to compliance the electrical requirements. It depends on the shape of the conductive contact which decide the compression range. The conductive contact 500 shown in Figure 5 has a C-shape or an arc-shape. However, other shapes e.g. a 7-shape or a Z- shape may also be possible. Since sheet metal or metal strip plate is very thin and small, so it may need two layers or two plates to make a spring type contact more rigid with good contact force. Therefore, the conductive contact 500 may be single or twin strip plates depends on different requirements for tolerance range and total electrical compliance.

The connecting structure 311, 312, 500 is a spring type contact with low profile which may be configured to connect two circuit boards PCB1 , PCB2 with a distance less than 5 millimetre (mm), e.g. 2-3 mm, between the two circuit boards PCB1 , PCB2.

The conductive contact 311 , 312, 500 may be made of elastic metal material, e.g. high-strength, high-elastic copper alloy, by e.g. stamped forming.

Figure 6 is a schematic perspective view of an example conductive contact 600 according to embodiments herein with an insulating body 620 and a number of conductive contacts 611 , 612. The conductive elastic frame is not shown. The insulating body 620 looks like a Lego block for optimal placement of conductive contacts, mechanical support and friendly to installation.

The insulting body 620 may have one or more protrude structures 621 , e.g. stoppers or pillars, to prevent the over bent of conductive contacts and to be suitable for wider tolerance range.

For some applications, two circuit boards may need to have parallel misalignment, the insulting body 620 may be designed with guiding feature for this parallel misalignment. So the insulting body 620 may comprise a guiding structure 622 for parallel misalignment between two circuit boards. As can be seen in Figures 3 and 6, the conductive contacts 311 , 312, 611 , 612 are retained in the insulting body 320, 620 as a connector in traditional sense, placed in line. The conductive contacts 311 , 312, 611 , 612 may be arranged and optimized by simulations, which make it convenient for production and assembly with simple structure and easy manufacturing technology and can achieve very small pitches and high density. For example, the connecting structure 300, 600 according to embodiments herein may be massive produced by automatic manufacturing technology by inserting the conductive contacts 311 , 312, 500, 611 , 612 in the insulting body 320, 620 with optimized pattern, and then being mounted with soldering balls on the circuit board.

Figure 7 is a schematic perspective view of an example conductive elastic frame 730 according to embodiment herein. The conductive elastic frame 730 shall surround one or several conductive contacts 311 , 312, 500, 611 , 612 with different sizes and different patterns and the insulting body 320, 620. The conductive elastic frame 730 may be a customized conductive elastomer gasket designed and optimized for a desired conductivity and a desired compress range, e.g. high conductivity and suitable compress range. The conductive elastic frame 730 may also have different shape.

The conductive elastic frame 730 may be soldered on a print circuit board and is friendly to production. With the conductive elastic frame 730, the conductive contacts can achieve extremely high isolations between different RF signals.

The connecting structure 300, 600 according to embodiments herein is friendly to circuit board plating, layout, soldering, and installation in radio units or radio modules. The connecting structure 300, 600 is applicable for most scenarios for short mating height between two print circuit boards. Figure 8 shows an example of board-to-board connecting application using the connecting structure 300, 600. In the example shown in Figure 8, the two circuit boards PCB1 and PCB2 is connected by a conductive contact 810. The two circuit boards PCB1 and PCB2 have parallel misalignment, and an insulting body 820 comprises a guiding structure 822 for the parallel misalignment between the two circuit boards PCB1 and PCB2 is provided. The insulting body 820 also comprises several protrude structures 821 shown as stoppers or pillars in Figure.

Figure 9 shows a simplified example for board-to-board connections using the structure 300, 600. The conductive contacts 911 , 912 may be soldered by soldering balls 913, 914 on one circuit board, e.g. PCB1 , fixed with an insulting body 920 and shielded by a conductive elastic frame (not shown). Then another circuit board, e.g. PCB2, is installed and compressed to all the tips, i.e. the contact section, of the conductive contacts 911 , 912, to implement a flexible RF connection up to 15 GHz.

Figure 10 is a flow chart illustrating a method for manufacturing the connecting structure 300, 600 according to embodiment herein. The method comprises the following actions which may be performed in any suitable order.

Action 1010

Forming at least two conductive contacts 311 , 312, 500, 611, 612, 810, 911 , 912, at least one conductive contact for signal path and at least one conductive contact for signal return path, with elastic metal material by e.g. stamped forming the at least two conductive contacts with copper alloy.

The connecting structure 300, 600 according to embodiments herein has very low cost due to adopting to continuous high-speed stamping process and assembly process.

Action 1020

Mounting the at least two conductive contacts 311 , 312, 500, 611 , 612, 810, 911 , 912, non-coaxially side by side with a predefined distance d between the at least two conductive contacts 311 , 312, 500, 611 , 612, 810, 911 , 912, on an insulating body 320, 620, 820, 920 by inserting a portion of the conductive contact 311 , 312, 500, 611, 612, 810, 911 , 912 into the insulating body 320, 620, 820, 920.

Action 1030

Mounting a conductive elastic frame 330, 630 surround the at least two conductive contacts 311 , 312, 500, 611 , 612, 810, 911 , 912 and the insulating body 320, 620, 820, 920.

The connecting structure 300, 600 may be employed in electronic devices or apparatus, communication equipment such as radio unit, radio module, antenna system etc. Figure 11 shows a block diagram for an electronic apparatus 1100 in which the connecting structure 300, 600 according to embodiments herein may be used. The electronic apparatus 1100 may comprise a transceiver or radio board TX/RX 1110, a power amplifier (PA) board PA 1120, an antenna board AT 1130 etc. The electronic device 1100 may comprise other units, where a processing unit 1140, a memory 1150, are shown. The electronic apparatus 1100 may be any one of a base station, a communication equipment, a remote radio unit, an antenna system etc. for a communication system.

To summarize, the connecting structure 300, 600 according to embodiments herein for board-to-board RF connection can achieve high RF performance. All conductive contacts are shielded by the surrounding conductive elastic frame, to prevent signal leakage and achieve extremely high isolation between different RF signals no matter how close those RF signal transmissions.

The placement of conductive contacts 311 , 312, 500, 611, 612, 810, 911 , 912 may be optimized and can be very high density, e.g. the pitches may be 2mm or less than 2mm. The connecting structure 300, 600 can achieve small footprint with BGA soldering, and lower mating height less than 5mm between two circuit boards.

The conductive contacts 311 , 312, 500, 611, 612, 810, 911 , 912 are able to flex toward one of the faces of the insulating body 320, 620, 820, 920, and can take any closer position when acted upon by a pressure force from a complementary connection contact in the second board PCB2. One side of the conductive contacts 311 , 312, 500, 611 , 612, 810, 911 , 912 is soldered to another connection contact in the first board PCB1.

Some advantages of the embodiments herein include but not limited to the following:

The conductive contacts 311 , 312, 500, 611, 612, 810, 911, 912 are inserted in the insulting body 320, 620, 820, 920 with optimized pattern, and then mounted with soldering balls. So the connecting structure 300, 600 can be massive produced by automatic manufacturing technology.

The conductive contacts 311 , 312, 500, 611, 612, 810, 911, 912 have longitudinal and transverse flexibility, larger tolerance capability during signal transmissions. So the connecting structure 300, 600 can meet tough misalignment tolerance and mating height requirements on real products applications.

The placement of the conductive contacts 311 , 312, 500, 611, 612, 810, 911, 912 can be optimized to have very high density with small footprint by BGA soldering.

The connecting structure 300, 600 is friendly to mass production with simple structure and easy manufacturing technology.

The connecting structure 300, 600 is friendly to circuit board plating, layout, soldering, The connecting structure 300, 600 is friendly for installation in radio units or modules. The connecting structure 300, 600 has very low cost due to adopting to continuous high-speed stamping process and assembly process.

The connecting structure 300, 600 has very good RF performance and excellent isolations between different RF signals thanks to the conductive elastic frame (330, 730).

The embodiments described herein are just examples. The connecting structures 300, 600 are not limited to the specific details of the above description, and various modifications on all elements e.g. the conductive contacts, the insulating body and the conductive elastic frame according to this non-coaxial principle may be made, for applications in different radio products. Various features and mechanical elements described above may be combined and optimized in any suitable manner. The word "comprise" or “comprising”, when used herein, shall be interpreted as nonlimiting, i.e. meaning "consist at least of".

The embodiments herein are not limited to the above described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appended claims.

Claims

1. A connecting structure (300, 600) for connecting two or more circuit boards (PCB1 , PCB2) comprising: at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912), one conductive contact (311 , 611) for signal path and one conductive contact (312, 612) for signal return path; an insulating body (320, 620, 820, 920); a conductive elastic frame (330, 730); wherein the at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912) are mounted, non-coaxially side by side with a predefined distance between the at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912), on the insulating body (320, 620, 820, 920), and the insulating body (320, 620, 820, 920) is surrounded by the conductive elastic frame (330, 730).

2. The connecting structure (300, 600) according to claim 1 , wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) comprises an elastic body (510) configured to have longitudinal and transverse flexibility.

3. The connecting structure (300, 600) according to claim 2, wherein the elastic body (510) comprises a contact section (511), a transition section (512) and a supporting section (513) which are configured to be flexible or movable in longitudinal and transverse direction.

4. The connecting structure (300, 600) according to claim 3, wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) further comprises a fixture section (514) configured to be inserted in the insulating body (320, 620, 820, 920), and a soldering ball (515) configured to be soldered on a connection contact of a circuit board.

5. The connecting structure (300, 600) according to any one of claims 1-4, wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) has a shape depends on required mating height, compression range and total electrical compliance length.

6. The connecting structure (300, 600) according to claim 5, wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) has any one of a C-shape, an arcshape, a 7-shape, a Z-shape.

7. The connecting structure (300, 600) according to any one of claims 3-6, wherein the soldering ball (515) is configured to be soldered on a connection contact of a first circuit board (PCB1), and when a pressure force from a complementary connection contact of a second circuit board (PCB2) is applied on the contact section (511) of the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912), the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) is able to flex toward one of the faces of the insulating body (320, 620, 820, 920).

8. The connecting structure (300, 600) according to any one of claims 1-7, wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) is made of elastic metal material.

9. The connecting structure (300, 600) according to any one of claims 1-8, wherein the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) is made of copper alloy.

10. The connecting structure (300, 600) according to any one of claims 1-9, wherein the connecting structure (300, 600) are configured to connect two circuit boards (PCB1, PCB2) with a distance less than 5 millimetre between the two circuit boards (PCB1, PCB2).

11. The connecting structure (300, 600) according to any one of claims 1-10, wherein the predefined distance between two conductive contacts (311 , 312, 611 , 612, 810,

911 , 912) is 2mm or less than 2mm.

12. The connecting structure (300, 600) according to any one of claims 1-11 , wherein the connecting structure (300, 600) comprises more than two conductive contacts mounted on the insulating body (320, 620, 820, 920) in a single-ended signal pattern (411 , 412) or a differential signal pattern (413, 414, 415).

13. The connecting structure (300, 600) according to any one of claims 1-12, wherein the insulting body (320, 620, 820) comprises a guiding structure (622, 822) for parallel misalignment between two circuit boards.

14. The connecting structure (300, 600) according to any one of claims 1-13, wherein the insulting body (320, 620, 820) comprises at least one protrude structure (621 , 821) to prevent the over bent of the conductive contact (311, 312, 500, 611 , 612, 810, 911 , 912).

15. The connecting structure (300, 600) according to any one of claims 1-14, wherein the conductive elastic frame (330, 730) is a customized conductive elastomer gasket designed and optimized for a desired conductivity and a desired compress range.

16. The connecting structure (300, 600) according to any one of claims 1-15, wherein the conductive elastic frame (330, 730) is configured to be soldered on a circuit board.

17. An electronic apparatus (1100) comprising a connecting structure (300, 600) according to any one of the embodiments 1-16.

18. A method for manufacturing a connecting structure (300, 600) comprising: forming (1010) at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912), one conductive contact for signal path and one conductive contact for signal return path, with elastic metal material; mounting (1020) the at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912), non-coaxially side by side with a predefined distance between the at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912), on an insulating body (320, 620, 820) by inserting a portion of the conductive contact (311 , 312, 500, 611 , 612, 810, 911 , 912) into the insulating body (320, 620, 820, 920); and mounting (1030) a conductive elastic frame (330, 730) surround the at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912) and insulating body (320, 620, 820, 920).

19. The method according to claim 18, wherein forming (1010) at least two conductive contacts (311 , 312, 500, 611 , 612, 810, 911 , 912) comprises stamped forming the at least two conductive contacts 311 , 312, 500, 611 , 612, 810, 911 , 912) with copper alloy.