Frequency-division multiplexing antenna array

Abstract

The present invention relates to a phased antenna array comprising a plurality of elementary antennas, each elementary antenna comprising a wide-frequency radiating element for the transmission of an electromagnetic wave from the antenna to the exterior and / or for the reception of an electromagnetic wave by the antenna from the exterior, a frequency-division multiplexer connected to the radiating element, the frequency-division multiplexer discriminating at least two frequency bands of an electromagnetic wave propagated in the frequency-division multiplexer, and at least two printed circuits, each printed circuit being associated with exactly one frequency band from among the at least two frequency bands, and each printed circuit comprising a beamforming integrated circuit, characterised in that the radiating element and the frequency-division multiplexer are obtained by metal additive manufacturing so as to form a single monolithic element, and in that a width of each radiating element measured in a plane perpendicular to a direction of propagation in the radiating element is less than or equal to the wavelength at the maximum operating frequency of the antenna array. The invention further relates to a method for manufacturing a phased antenna array.

Description

Frequency-division multiplexed antenna array technical field

[0001] The present invention relates to a phase-controlled antenna array and a method for manufacturing such an array. State of the art

[0002] Phase-controlled antenna arrays are antenna systems that control the distribution of electromagnetic waves, i.e. the phase and amplitude in the aperture of the antenna array, by means of electronic circuits, in order to control the characteristics of the antenna beam such as its direction, its polarization(s), its power, its width, etc.

[0003] Most known phased-array antennas typically cannot operate on multiple frequency bands simultaneously, and therefore cannot operate in multiple modes at the same time, e.g., transmit (TX) and receive (RX) simultaneously. Typically, these arrays are equipped with a TX-RX switch to activate one mode or the other alternately. Consequently, the data rate of such an antenna array is reduced since it can only operate in one mode at a time.

[0004] A well-known solution involves using two antennas, one for each frequency band, to maximize the network's bandwidth. This solution provides a high level of isolation between frequency bands, thus preventing interference between different modes. It also allows for coverage of wide frequency ranges, since a single antenna typically cannot cover two frequency bands simultaneously.

[0005] To operate on multiple frequency bands while maintaining sufficient isolation between them, a diplexer or frequency multiplexer is commonly used. These filtering devices separate communication channels and provide adequate isolation between frequency bands.

[0006] However, existing multiplexers are either bulky and therefore difficult to integrate into phase-controlled networks, or miniaturized, but then suffer from significant losses which limit the possibilities of the system. Brief summary of the invention

[0007] One aim of the present invention is to provide a phase-controlled antenna array free from the limitations of the prior art.

[0008] Another objective of the invention is to provide a compact phase-controlled antenna array enabling frequency multiplexing.

[0009] Another aim of the invention is to propose a method for manufacturing such a phase-controlled antenna array.

[0010] According to the invention, these goals are achieved in particular by means of a phase-controlled antenna array comprising a plurality of elementary antennas, each elementary antenna comprising a broadband frequency radiating element enabling the emission of an electromagnetic wave from the antenna to the outside and / or the reception of an electromagnetic wave from the outside to the antenna, a frequency multiplexer connected to the radiating element, the frequency multiplexer enabling the discrimination of at least two frequency bands of an electromagnetic wave propagated in the frequency multiplexer, at least two printed circuit boards, each printed circuit board being associated with exactly one frequency band among the at least two frequency bands and each printed circuit board comprising a beamforming integrated circuit, characterized in that the radiating element and the frequency multiplexer are obtained by metallic additive manufacturing so as to form a single monolithic element and in that a width of each radiating element measured in a plane perpendicular to a propagation direction in the radiating element is less than or equal to the wavelength at the maximum operating frequency of the antenna array.

[0011] Such an antenna array therefore makes it possible to combine several isolated frequency bands in a single aperture, i.e. in a single radiating element per elementary antenna.

[0012] Additive manufacturing (or 3D printing) of the radiating elements and multiplexers of each elementary antenna allows obtaining a monolithic portion increasing the compactness of the antenna network by limiting the need for means of fixing between the different elements, thus simplifying the interfaces during manufacturing and integration.

[0013] The width, that is, the size of the aperture, does not exceed the wavelength at the maximum operating frequency of the antenna array. In this way, it is possible to increase the compactness of the array according to its maximum operating frequency.

[0014] The term "frequency band" is used here in a broad sense and can notably mean that the frequency band covers several distinct frequency sub-bands (also called multiband). Thus, each elementary antenna can, for example, operate in multiband frequency in reception and in multiband frequency in transmission on a single radiating element.

[0015] The at least two printed circuit boards of each elementary antenna can be arranged consecutively along the direction of wave propagation in the elementary antenna. The printed circuit boards (or PCBs) can therefore be stacked according to the propagation direction.

[0016] This PCB layout significantly reduces the surface area (in a direction perpendicular to the propagation direction) required for the electronic components of the antenna array, thus increasing its compactness. It also improves frequency isolation to minimize noise issues.

[0017] When the PCBs are stacked in this way, the multiplexer of each elementary antenna can be connected to the integrated circuit of each elementary antenna PCB using coaxial connecting lines, with at least one coaxial connecting line passing through an intermediate PCB. This avoids increasing the surface area perpendicular to the propagation direction for connecting the electronics (especially the integrated circuits) to the rest of the antenna array.

[0018] To increase frequency isolation between integrated circuits dedicated to different frequency bands, the antenna array may include at least two layers of metallic insulation, each metallic insulation layer being adjacent to a printed circuit board and delimiting an internal volume configured to accommodate the beamforming integrated circuit of the printed circuit board adjacent to the metallic insulation layer.

[0019] An integrated circuit dedicated to a specific frequency band is thus isolated from other integrated circuits located on adjacent or nearby printed circuit boards by means of metallic insulation layers. The internal volumes are, for example, delimited by the printed circuit board on which the circuit is located. integrated on one side, and on the other side by internal walls of the metallic insulation layer.

[0020] To optimize the available space on printed circuit boards for electronics, one or both sides of each printed circuit board can be used to support electronic components, especially beamforming integrated circuits.

[0021] Surprisingly, using the printed circuit board faces facing the frequency multiplexer to support electronic components (especially beamforming integrated circuits) allows the monolithic metal block formed by the multiplexer and the radiating element of the elementary antenna to be used as a heat sink.

[0022] According to one embodiment, the frequency multiplexer includes at least two filters, each filter being configured to accept exactly one frequency band out of the at least two frequency bands (i.e. to filter / reject all other frequency bands) and each filter being a waveguide filter or a coaxial filter.

[0023] The frequency multiplexer can, for example, include a first filter for one frequency band for reception and a second filter for one frequency band for transmission. Thus, the antenna array can operate simultaneously in two modes.

[0024] However, the frequency multiplexer can include more than two frequency filters. These filters are typically connected in parallel, each then being connected to a specific printed circuit board and a beamforming integrated circuit configured to operate at the frequency accepted by the filter.

[0025] Each filter of the frequency multiplexer can be connected to the corresponding beamforming integrated circuit by a coaxial connection line.

[0026] The frequency multiplexer of each elementary antenna can be connected to the corresponding radiating element by means of a coaxial connecting line or by means of a waveguide.

[0027] To increase the compactness of the network, the radiating elements can include three grooves to allow their miniaturization while maintaining a wide bandwidth.

[0028] Advantageously, the three grooves are arranged so that the cross-section of the radiating element is invariant under rotation in a plane perpendicular to the direction of propagation. For example, if the cross-section of the radiating element is circular, the three grooves are typically arranged angularly at 120° to each other.

[0029] According to one embodiment, and in order to increase the compactness of the network, the radiating elements can be of the Vivaldi type in order to allow their miniaturization while maintaining a wide bandwidth.

[0030] Advantageously, each radiating element can combine the advantages of having three striations and protrusions of a Vivaldi-type antenna.

[0031] According to one embodiment, the elementary antennas can be arranged contiguously along a first direction forming a one-dimensional array.

[0032] Additionally, the elementary antennas can be further arranged contiguously along a second direction, forming a two-dimensional network.

[0033] The antenna array can be single or dual polarized.

[0034] The elementary antennae can be arranged relative to each other to form a triangular, rectangular, or hexagonal pattern.

[0035] The cross-section of each elementary antenna can be circular, triangular, rectangular, square, pentagonal, hexagonal, heptagonal, octagonal, or polygonal with more than eight sides. These polygons can be regular or irregular. The cross-section can also be composed of curved portions or a combination of curved and straight portions. In particular, the cross-section can be configured to be suitable for additive manufacturing along the chosen manufacturing axis.

[0036] The surface of the antenna array at the level of the radiating elements can be flat or curved (e.g. in the case of a confocal array).

[0037] The cross-section of each radiating element may be identical or different from the cross-section of any waveguides composing the frequency multiplexer.

[0038] Although generally obtained by metal additive manufacturing, all or part of the additively manufactured elements of this antenna array can be obtained by 3D printing of polymer and / or ceramic and then coated with a layer of conductive metal (i.e. metallization).

[0039] According to the invention, these goals are achieved in particular by means of a method for manufacturing a phase-controlled antenna array comprising the steps of: additively manufacturing a plurality of metallic elementary antennas arranged in an array, each elementary antenna comprising a radiating element and a frequency multiplexer enabling discrimination of at least two frequency bands of an electromagnetic wave propagated in the frequency multiplexer, the plurality of elementary antennas forming a monolithic assembly, assembling the plurality of elementary antennas with at least two printed circuits, each printed circuit being associated with exactly one frequency band among the at least two frequency bands and each printed circuit comprising a beamforming integrated circuit.

[0040] The at least two printed circuit boards of each elementary antenna can be arranged consecutively along a direction of wave propagation in the elementary antenna.

[0041] The multiplexer of each elementary antenna can be connected to the integrated circuit of each printed circuit board of the elementary antenna by means of coaxial connecting lines, at least one coaxial connecting line passing through an intermediate printed circuit board.

[0042] The method may further include a step of disposing of at least two metallic insulation layers, each metallic insulation layer being associated with a printed circuit board and each metallic insulation layer delimiting an internal volume configured to accommodate the beamforming integrated circuit of the printed circuit board associated with the metallic insulation layer. Brief description of the figures

[0043] Examples of implementation of the invention are given in the description illustrated by the accompanying figures, in which: Figure 1 schematically illustrates an elementary antenna in a phase-controlled antenna array. • Figure 2 schematically illustrates a frequency multiplexer connected to a plurality of printed circuits. • Figure 3 schematically illustrates a plurality of devices from Figure 2 organized in a network. • Figure 4 schematically illustrates a frequency multiplexer connected to a plurality of printed circuit boards, both sides of which are used to accommodate integrated circuits. Example(s) of an embodiment of the invention

[0044] As illustrated in Figure 1, each elementary antenna 1 of the phase-controlled antenna array comprises a radiating element 10 connected to a frequency multiplexer 20 for discriminating at least two frequency bands. The multiplexer is itself connected to at least two printed circuit boards 30, each printed circuit board including a beamforming integrated circuit 31. Each integrated circuit 31 is configured to operate in one of the frequencies discriminated by the frequency multiplexer 20.

[0045] Each radiating element has a width L, measured in a plane perpendicular to the propagation direction z of a wave in the elementary antenna, less than or equal to one times the wavelength at the maximum operating frequency of the antenna array.

[0046] As illustrated in Figure 2, the frequency multiplexer 20 can include a plurality of frequency filters, e.g., two frequency filters 21, 22 (e.g., for simultaneous transmission and reception). Each of these frequency filters is connected on one side to a radiating element (not shown in Figure 2), and on the other hand to a printed circuit board 30 including an integrated circuit 31 corresponding to the operating frequency of the filter. Other electronic components, e.g. amplifiers, can also be arranged on the printed circuit boards 30 and connected to the filters and / or integrated circuits 31.

[0047] As illustrated in Figure 2, the at least two printed circuit boards 30 can be stacked along the propagation direction z so as to increase the compactness of each elementary antenna 1 in the plane perpendicular to the propagation direction z. Generally, the number of stacked printed circuit board layers corresponds to the number of operating frequencies of the antenna array.

[0048] As illustrated in Figure 2, the integrated circuits 31 can be isolated from each other by means of metallic insulation layers 32. These layers delimit one or more internal volume(s) in which the electronic components, in particular the integrated circuits 31, are accommodated.

[0049] With the exception of printed circuits and electronic components, the antenna array can thus be made entirely of metal, including the frequency isolation layers 32. It is therefore possible to use no dielectric elements in the antenna array.

[0050] As illustrated in Figure 3, the elementary antennas 1 can be arranged contiguously to form a one- or two-dimensional array.

[0051] According to one embodiment, the printed circuits 30 associated with the same frequency for each elementary 1 are formed by a single printed circuit whose dimensions correspond to the number of elementary antennas of the network.

[0052] During manufacturing, it is therefore possible to connect the monolithic block formed by the additively manufactured assembly comprising the multiplexers 20 and the radiant elements 10 directly onto a printed circuit board 30 or onto a stack of printed circuit boards 30 as explained above.

[0053] As illustrated in Figure 4, it is possible to arrange the electronic components, and in particular the beamforming integrated circuits 31, on both sides of a printed circuit board 30. As explained above, this allows in particular the use of the monolithic metallic block formed by the additively manufactured assembly comprising the multiplexers 20 and the radiating elements 10 as a heat sink to remove the heat generated by the electronics. Reference numbers used in the figures 1 Element antenna 0 Radiating element 0 Frequency multiplexer 1 Filter 2 Filter 0 Printed circuit board 1 Beamforming integrated circuit 2 Metallic insulation layer 0 Coaxial connection line L Width of a radiating element Direction of propagation

Claims

Demands 1. Phase-controlled antenna array comprising a plurality of elementary antennas (1), each elementary antenna comprising a broadband radiating element (10) for transmitting an electromagnetic wave from the antenna to the outside and / or receiving an electromagnetic wave from the outside to the antenna, a frequency multiplexer (20) connected to the radiating element, the frequency multiplexer for discriminating at least two frequency bands of an electromagnetic wave propagated in the frequency multiplexer, at least two printed circuit boards (30), each printed circuit board being associated with exactly one frequency band among the at least two frequency bands and each printed circuit board comprising a beamforming integrated circuit (31),characterized in that the radiating element and the frequency multiplexer are obtained by metallic additive manufacturing so as to form a single monolithic element, and in that a width (L) of each radiating element measured in a plane perpendicular to a propagation direction (z) in the radiating element is less than or equal to the wavelength at the maximum operating frequency of the antenna array.

2. Antenna array according to claim 1, the at least two printed circuits (30) of each elementary antenna (1) being arranged consecutively along the propagation direction (z) of the waves in the elementary antenna (1).

3. Antenna array according to claim 2, the multiplexer (20) of each elementary antenna (1) being connected to the integrated circuit (31) of each printed circuit board (30) of the elementary antenna by means of coaxial connecting lines (40), at least one coaxial connecting line (40) passing through an intermediate printed circuit board (30).

4. Antenna array according to any one of claims 2 to 3, comprising at least two metallic insulation layers (32), each metallic insulation layer being adjacent to a printed circuit board (30) and delimiting an internal volume configured to accommodate the beamforming integrated circuit (31) of the printed circuit board adjacent to the metallic insulation layer.

5. Antenna array according to any one of claims 2 to 4, each integrated circuit (31) being disposed on a face of the printed circuit board (30) opposite the frequency multiplexer (20) with respect to the propagation direction (z) and / or on a face of the printed circuit board (30) on the side of the frequency multiplexer (20) with respect to the propagation direction (z).

6. Antenna array according to any one of claims 1 to 5, the frequency multiplexer (20) comprising at least two filters (21,22), each filter being configured to accept exactly one frequency band among the at least two frequency bands and each filter being a waveguide filter or a coaxial filter.

7. Antenna array according to claim 6, each filter (21,22) of the frequency multiplexer (20) being connected to the corresponding integrated circuit (31) by a coaxial connection line (40).

8. Antenna array according to any one of the preceding claims, the frequency multiplexer (20) of each elementary antenna (1) being connected to the radiating element (10) of the elementary antenna by means of a coaxial connecting line or by means of a waveguide.

9. Antenna array according to any one of the preceding claims, each radiating element (10) comprising three grooves.

10. Antenna array according to any one of the preceding claims, each radiating element (10) being of the Vivaldi type.

11. Antenna array according to any one of the preceding claims, the elementary antennas (1) being arranged contiguously along a first direction forming a one-dimensional array.

12. Antenna array according to the preceding claim, the elementary antennas (1) being additionally arranged contiguously along a second direction forming a two-dimensional array.

13. Method for manufacturing a phase-controlled antenna array comprising the steps of: additively manufacturing a plurality of metallic elementary antennas (1) arranged in an array, each elementary antenna comprising a radiating element (10) and a frequency multiplexer (20) allowing discrimination of at least two frequency bands of an electromagnetic wave propagated in the frequency multiplexer, the plurality of elementary antennas (1) forming a monolithic assembly, assembling the plurality of elementary antennas (1) with at least two printed circuit boards (30), each printed circuit board being associated with exactly one frequency band among the at least two frequency bands and each printed circuit board (30) comprising a beamforming integrated circuit (31).

14. Method according to claim 13, the at least two printed circuits (30) of each elementary antenna (1) being arranged consecutively along a propagation direction (z) of the waves in the elementary antenna (1).

15. Method according to claim 14, the multiplexer (20) of each elementary antenna (1) being connected to the integrated circuit (31) of each printed circuit board (30) of the elementary antenna by means of coaxial connecting lines (40), at least one coaxial connecting line (40) passing through an intermediate printed circuit board (30).

16. A method according to any one of claims 14 to 15, further comprising a step of arranging at least two metallic insulation layers (32), each metallic insulation layer (32) being associated with a printed circuit board (30) and each metallic insulation layer delimiting an internal volume configured to accommodate the beamforming integrated circuit (31) of the printed circuit board (30) associated with the metallic insulation layer.

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