General-purpose BFIC front-end antenna tile assembly

Abstract

This provides a general-purpose beamformer integrated component (BFIC) tile for the front-end portion of the antenna. [Solution] The active antenna comprises a multilayer printed circuit board 1 and a BFIC component 18, the multilayer printed circuit board including at least one RF track 13 and at least one ground track 20, each terminating at one end on the inner surface of the printed circuit board within a connection portion 21 and at the other end on the outer surface of the printed circuit board within a connection portion 22, the RF track 13 and ground track 20 including coaxial connection portions within each layer of the printed circuit board, coaxial connection portions terminating on each surface within a coaxial pad and microstrip lines for connecting two coaxial pads of the track between layers, the inner layer 23 of the printed circuit board including a basic grouping of one or two coaxial pads arranged according to a regular grid.

Description

Technical Field

[0001] The present invention relates to a generic BFIC tile assembly that integrates the front - end part of an antenna.

Background Art

[0002] The "front - end" of an antenna means the part that processes the signal before amplification in a receiving or transmitting antenna system.

[0003] The present invention targets active antennas ranging from the Ku - band starting at 10 GHz to microwaves (above 40 GHz). This applies to all types of analog beam - forming components. In particular, it is useful for active antennas when the constraints on density and integration are severe, especially in relation to amplification or radiation functions.

[0004] Within the framework of the development of an active antenna front - end, as illustrated in Figure 1, several functional elements, namely - Antenna panel (radiating elements: horn, patch, slot...), - Power or low - noise amplification substrate, [[ID=2⑤]] - Substrate that integrates components used for beam - forming, called Beam Former Integrated Components (BFIC), - Digital substrate that enables real - time beam - forming management, called Antenna Control Unit (ACU), - Frequency - conversion substrate that enables conversion of RF signals to base - band or vice versa, - Metal structure for shielding and heat dissipation, - Various interconnecting and interface elements (electrical, mechanical, and thermal) must be interconnected.

[0005] Figure 1 illustrates a schematic of the RF frontend concept that implements the elements listed above.

[0006] For this assembly to function correctly, the BFIC board and the radiating element must be able to be associated. A simple solution involves printing the antenna directly on the side of the printed circuit board opposite to the side where the BFIC is wired. Alternatively, these elements can be irreversibly bonded by adhesive or soldering, or interconnected using RF connectors. Each of these solutions requires designing specific tiles depending on the use case.

[0007] To limit costs and optimize losses, designers aim to minimize the number of components and share as many functions as possible. Therefore, it is very common to see BFIC tiles that integrate a BFIC on one side and a patch antenna on the other. In this case, the functions cannot be separated. If it is desirable to change the type of radiating element to achieve different performance for a different application, the BFIC tile must be specially redesigned, which incurs significant costs.

[0008] A tile with integrated patch antennas is known. Patch antennas require the implementation of thick substrate layers that do not enable the realization of symmetric printed circuit layer stacks, which violates printed circuit design rules and impairs large-scale manufacturability and reliability.

[0009] This type of assembly poses a significant risk because the different properties of the materials constituting the substrate and antenna cause differences in expansion that affect the reliability of the assembly. Furthermore, the two elements, namely the substrate and the antenna panel, are not removable, posing a major problem for repairability.

[0010] To separate the radiating elements from the BFIC substrate, they can be equipped with connectors on the side opposite to the side where the BFIC is integrated. In this case, it is necessary to have space to integrate a large number of connectors on both the BFIC tile and the radiating elements. This has proven to be potentially impossible when the interconnection signal density is high (high frequency). Above all, if it turns out that this is feasible, this approach will be extremely expensive because these connectors are very costly.

[0011] In known examples, aligning components during assembly is generally a complex task. Furthermore, this type of design is prohibitively expensive. Transmission losses in high-frequency connectors are also extremely high. [Overview of the Initiative] [Problems that the invention aims to solve]

[0012] The objective of the present invention is to overcome the aforementioned drawbacks, and more specifically, to propose a general-purpose BFIC tile for the front-end portion of an antenna. [Means for solving the problem]

[0013] According to one aspect of the present invention, a general-purpose BFIC tile assembly for the front end portion of an antenna is provided, the front end portion of which is - Multilayer printed circuit boards, - At least one BFIC component, - Solder balls between the BFIC component and the outer surface of the printed circuit board, - A multilayer printed circuit board, - At least one RF track in a printed circuit board that terminates at one end on the inner surface of the printed circuit board within a coaxial pad, and at the other end on the outer surface of the printed circuit board within the coaxial pad, - comprising at least one ground track of a printed circuit board that terminates at one end on the inner surface of the printed circuit board within the coaxial pad and at the other end on the outer surface of the printed circuit board within the coaxial pad, The RF track and ground track are multilayer printed circuit boards that include coaxial connections within each layer of the printed circuit board, coaxial connections terminating on each surface within the coaxial pads, and, for example, microstrip lines (microstrips in English) with an impedance of 50Ω for connecting the two coaxial pads of the track between layers. - The inner layer of the printed circuit board has a basic grouping of one or two coaxial pads arranged in a regular grid. It is equipped with.

[0014] In one embodiment, the basic grouping of one or two coaxial pads is configured to be arranged in a square grid.

[0015] According to one embodiment, the inner layer of a multilayer printed circuit board equipped with a coaxial pad is square in shape.

[0016] In one embodiment, the basic grouping of one or two coaxial pads is configured to be arranged in an equilateral triangular grid.

[0017] A triangular lattice refers to a lattice in which the basic grouping of one or two coaxial pads forms a triangle, such as an isosceles triangle or even an equilateral triangle, and such a triangular lattice is denser than a rectangular or even square lattice.

[0018] According to one embodiment, the internal layer equipped with coaxial pads is substantially square in shape, and its opposing sides have a complementary shape such that two consecutive tile assemblies can interlock, and the arrangement of pads on the two tiles remains in an equilateral triangular grid.

[0019] In one embodiment, the pitch between the two groupings is half the wavelength of the highest frequency in the instantaneous bandwidth of the transmitted signal.

[0020] According to one embodiment, the printed circuit board includes, on its inner surface, for each coaxial pad, at least one solder ball disposed at the center portion of the coaxial pad and at least two solder balls disposed on the outer periphery of the coaxial pad, ensuring a ground contact.

[0021] Also, according to another aspect of the present invention, an active antenna is proposed, which - at least one radiation element, - at least one tile assembly, - and at least one interposer disposed between the radiation element and the tile assembly is provided.

[0022] In one embodiment, the interposer is a high-frequency coaxial interposer.

[0023] According to one embodiment, the high-frequency coaxial interposer includes a diffusion contact portion.

[0024] The present invention is given alone by way of non-limiting examples and will become clearer after reading the following description given while referring to the drawings.

Brief Description of the Drawings

[0025] [Figure 1] It is a schematic diagram illustrating the concept of an RF front-end according to the prior art. [Figure 2] It is a schematic diagram illustrating a coaxial connection portion according to the prior art. [Figure 3] It is a schematic diagram illustrating a coaxial connection portion in a multilayer printed circuit board according to the prior art. [Figure 4] It is a schematic diagram illustrating a coaxial connection portion in a multilayer printed circuit board according to the prior art. [Figure 5] It is a schematic diagram illustrating a general-purpose BFIC tile assembly for the front-end portion of an antenna according to one aspect of the present invention. [Figure 6] This is a schematic diagram illustrating an active antenna according to one aspect of the present invention, which is equipped with at least one general-purpose BFIC tile assembly on the front end portion of the antenna. [Figure 7] This is a schematic diagram illustrating two inner and outer surfaces of a general-purpose BFIC tile assembly for the front end portion of an antenna, having a basic grouping of one or two coaxial pads arranged in an equilateral triangular grid, according to one aspect of the present invention. [Figure 8] This is a schematic diagram illustrating two inner and outer surfaces of a general-purpose BFIC tile assembly for the front end portion of an antenna, having a basic grouping of one or two coaxial pads arranged in an equilateral triangular grid, according to one aspect of the present invention. [Figure 9] This is a schematic diagram illustrating a plurality of general-purpose BFIC tile assemblies that are continuously mounted on a panel or radiating element according to one aspect of the present invention. [Modes for carrying out the invention]

[0026] In all figures, elements with the same reference number are similar.

[0027] Figure 2 is a schematic diagram illustrating a coaxial connection using the latest technology.

[0028] The coaxial connection consists of a central conductor 8 with radius a, an outer conductor 9 positioned at a distance or radius b from the central axis of the central conductor 8, and an insulator 10 that separates these, called a propagation medium. The propagation medium 10 has a relative permittivity ε r and relative permeability μ rIt is characterized by two physical quantities. Such a coaxial connection of length z allows the propagation of electromagnetic waves between its two ends, called the input and the output. In order for signal transmission to be optimized at the coaxial connection, it must exhibit a characteristic impedance that matches the characteristic impedance exhibited by the external elements (antenna, amplifier, transmitter, receiver, etc.) at its access point. This normalized characteristic impedance Z0 is given by the law

[0029]

number

[0030] It depends on the aforementioned physical quantities.

[0031] The normalized characteristic impedance of a coaxial conductor is generally 50Ω. Dimensions a and b are ε r and μ r It is selected such that an impedance of 50Ω is obtained for a given material for which it is known.

[0032] The coaxial connection can be formed by a cable (for example, Teflon® coated copper wire, all-metal coated copper wire) or by two pads on a printed circuit board connected by vias.

[0033] As illustrated in Figures 3 and 4, pads 11 and 12 are copper islands isolated from the rest of the copper planes 27, 28, and 29 on the surface of the multilayer printed circuit board 1, and are also called ground planes. Such pads 11 and 12 constitute contact-receiving areas with elements located outside the printed circuit board, such as the central conductor of a connector. Two pads 11 and 12, placed on either side of the multilayer printed circuit board 1 and connected by vias 13, form the central conductor.

[0034] The substrate or material constituting the printed circuit board constitutes the propagation medium. The three previously described elements 11, 12, and 13 form a coaxial connection whose characteristic impedance can reach 50 Ω when the geometric shape (a, b) is correctly selected.

[0035] The structure of the multilayer printed circuit board 1 allows for the interconnection of non-face-to-face signals. To do this, each layer 15, 16 of the printed circuit board 1 integrates coaxial connectors in a non-limiting manner, although this example is illustrated in Figures 3 and 4, which have only two layers 15, 16. The two coaxial connectors are connected to each other interlayer by a microstrip line 13 with an impedance of 50Ω (5). Pads present on one side of the printed circuit board 1 can then be connected to electronic components, for example, by soldering. Alternatively, pads 12 on the opposite side can be connected to an interconnection system such as a connector or an interposer, such as a flexible interposer, which can be connected to an antenna.

[0036] Two of the ground planes 27, 28, and 29, which are positioned around pads 11 and 12 and on either side of layers 15 and 16 connected by the crowns of conductive vias 14 with a spacing of less than λ / 10, form the outer conductor in Figure 2.

[0037] Furthermore, it is possible to connect the inputs or outputs of electronic components to external interconnection systems that do not have direct access.

[0038] In other words, as illustrated in Figure 5, the present invention relates to a general-purpose BFIC tile assembly for the front end portion of an antenna, the front end portion of which is - Multilayer printed circuit board 1, - At least one BFIC component 18, - A solder ball 19 is provided between the BFIC component 18 and the outer surface of the printed circuit board 1. - Multilayer printed circuit board 1 is - At least one RF track 13 in the printed circuit board 1 terminates at one end on the inner surface of the printed circuit board within the coaxial pad 11, and also terminates at the other end in the coaxial pad 12 on the outer surface of the printed circuit board 1, - A ground track 20 of the printed circuit board 1 terminates at one end on the inner surface of the printed circuit board 1 within the coaxial pad 21 and at the other end on the outer surface of the printed circuit board 1 within the coaxial pad 22, - RF track 13 and ground track 20 include 50Ω impedance microstrip lines for connecting coaxial connections within each layer of the printed circuit board, coaxial connections terminating on each surface within the coaxial pads, and two coaxial pads of the track between layers. - The inner layer 23 of the printed circuit board has a basic grouping of one or two coaxial pads arranged according to a regular grid.

[0039] The basic grouping of one or two coaxial pads is arranged according to a square grid, and the inner layers of the multilayer printed circuit board 1 having coaxial pads can be square in shape.

[0040] The basic grouping of one or two coaxial pads is arranged and configured according to an equilateral triangular grid, and the inner layer 23 equipped with the coaxial pads is substantially square in shape and has opposing sides having complementary shapes such that two consecutive tile assemblies can interlock and the arrangement configuration of the pad groupings on the two tiles forms an equilateral triangular grid.

[0041] Figure 6 shows an example of use in an active antenna with an interposer 24 and a radiating element 25. The interposer 24 may be a high-frequency coaxial interposer, for example, including a diffusion contact section 26.

[0042] A BFIC component integrates multiple inputs and / or outputs, and its primary function is to amplify the input or output signals so that they can be coupled in space when radiated through an antenna, while simultaneously altering their phase and amplitude; this is called spatial coupling. By controlling the phase of the BFIC component, it is also possible to perform scanning of coupling points; this is called electronic scanning.

[0043] Several BFIC components wired on the same outer surface of printed circuit board 1 can be interconnected to several pads on the opposite inner surface without the access being face-to-face (offset). This characteristic is important because, for spatially coupled devices to operate, the radiating elements must form a grid, and each unit element must be spaced at least half a wavelength λ apart (this is called an antenna array). The wavelength λ is proportional to the reciprocal of the operating frequency according to the equation λ = c / f, where c is the speed of light and f is the maximum operating frequency.

[0044] Because the different inputs and / or outputs of a BFIC component are not spaced at the same pitch as those of an antenna array, it is usually necessary to rely on coaxial connectors that are offset by the presence of multilayer circuitry.

[0045] A printed circuit board that considers the grid by having the spacing between the pads of the coaxial connection located on the antenna side be half a wavelength (λ / 2) of the highest frequency in the instantaneous bandwidth of the transmitted signal, enables spatial coupling at the board level. The grid can be triangular or square.

[0046] Such substrates are called base substrates or general-purpose beamforming tiles.

[0047] A complete antenna panel includes several basic beamforming substrates arranged in a continuous configuration such that the spacing between pads located on either side of two adjacent substrates remains constant. When this condition is met, the basic beamforming substrates are more precisely called general-purpose BFIC tiles.

[0048] As illustrated in Figure 7, in the case of a triangular lattice, the inner layer 23 of the general-purpose tile equipped with coaxial pads 22 is substantially square in shape, and its opposing sides are such that two consecutive tile assemblies can interlock, and the arrangement configuration of the grouping of pads on two tiles has a complementary shape to form an equilateral triangular lattice.

[0049] The complementary shapes of opposing edges can take any shape, as long as the pads maintain an equidistant distance from one substrate to the other, thus maintaining a uniform pattern.

[0050] Figure 8 schematically shows the other side of a general-purpose BFIC tile assembly.

[0051] Figure 9 schematically shows multiple general-purpose BFIC tile assemblies mounted in a continuous manner on a panel or radiating element 25.

[0052] The present invention - The ability to separate the tiles from the radiating elements ensures that the circuit board can be reliably repaired or replaced. - Because these tiles are not integrated within the RF connector, a large number of parts can be produced at the target cost. - It has a unique design that can be associated with any type of antenna or radiating element (patch, slot, 3D additive, etc.). This makes it possible to achieve different antenna performance from the same general-purpose brick (BFIC tile) without using costly and time-consuming new designs. - This allows for the provision of a symmetrical PCB structure that avoids the effects of bending or warping when passing through a reflow oven. It also allows for handling larger board formats and is therefore more economical. In fact, when patch antennas are incorporated into the board, the PCB structure inevitably becomes asymmetrical. - Instead of relying on radiation testing methods in an anechoic chamber (a simple vector network analyzer is sufficient), each RF path is automatically tested in series as before.

[0053] The present invention - Assembling multiple types of radiating panels using a single, identical version of tile, i.e., enabling several antenna performances to be achievable from the same tile, saving valuable design time. - The stacked structure of the symmetrical tiles allows for the mass production of circuits usable in multiple applications without costly specific design work, and - To produce low-cost tiles because RF connectors are excluded from the tiles, - When combined with flexible intervening devices, the presence of compatible interconnection areas for the flexible intervening devices allows for the production of repairable tiles. This makes it possible. [Explanation of symbols]

[0054] 1. Antenna panel, multilayer printed circuit board 2. Power or low-noise amplification board 3 circuit boards 4 Digital board 5 Frequency conversion board 6 Metal structure 8. Central conductor 9. Outer conductor 10 Insulator 11, 12 pads 13 Via, RF Truck 14 conductive vias 15, 16 layers 18 BFIC Components 19 solder balls 20 Grand Track 21 Coaxial Pads 22 Coaxial Pads 23 Inner layer 24 Interposer 25 Radiation element 26 Diffusion contact area 27, 28, 29 Ground Plane

Claims

1. A general-purpose BFIC front-end antenna tile assembly, wherein the front-end is - Multilayer printed circuit board (1), - At least one BFIC component (18), - The BFIC component (18) and the solder ball (19) between the outer surface of the printed circuit board (1) are provided. - The multilayer printed circuit board (1) is - At least one RF track (13) within the printed circuit board (1) terminates at one end on the inner surface of the printed circuit board (1) within the connection portion (11) and terminates at the other end within the connection portion (12) on the outer surface of the printed circuit board (1), - Includes at least one ground track (20) within the printed circuit board (1) that terminates at one end on the inner surface of the printed circuit board (1) within the connection portion (21) and at the other end on the outer surface of the printed circuit board (1) within the connection portion (22), - The RF track (13) and ground track (20) include coaxial connection points within each layer of the printed circuit board, coaxial connection points terminating on each surface within the coaxial pads, and microstrip lines for connecting two coaxial pads of the track between layers. - A general-purpose BFIC front-end antenna tile assembly in which the inner layer (23) of the printed circuit board includes a basic grouping of one or two coaxial pads arranged according to a regular grid.

2. The general-purpose BFIC tile assembly according to claim 1, wherein the basic grouping of one or two coaxial pads is arranged according to a square grid.

3. The general-purpose BFIC tile assembly according to claim 2, wherein the internal layer of the multilayer printed circuit board (1) equipped with coaxial pads (11, 21) is square in shape.

4. The general-purpose BFIC tile assembly according to claim 1, wherein the basic grouping of one or two coaxial pads is arranged in an equilateral triangular grid.

5. The general-purpose BFIC tile assembly according to claim 4, wherein the internal layer equipped with coaxial pads is substantially square in shape, and its opposing sides are complementary in shape such that two consecutive tile assemblies can interlock, and the arrangement configuration of the pad groupings on the two tiles forms an equilateral triangular grid.

6. The general-purpose BFIC tile assembly according to claim 1, wherein the pitch between two groupings is half the wavelength of the highest frequency wavelength in the instantaneous bandwidth of the transmitted signal.

7. The general-purpose BFIC tile assembly according to claim 1, wherein the printed circuit board (1) comprises, on its inner surface, at least one solder ball positioned in the central part of each coaxial pad, and at least two solder balls positioned on the outer circumference of the coaxial pad.

8. It is an active antenna, - At least one radiating element (25), - At least one tile assembly according to claim 1, - At least one interposer (24) is configured to be positioned between the radiating element (25) and the tile assembly. An active antenna equipped with [features / equipment].

9. The active antenna according to claim 8, wherein the interposer (24) is a high-frequency coaxial interposer.

10. The active antenna according to claim 9, wherein the high-frequency coaxial interposer (24) includes a diffusion contact portion (26).

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