Reconfigurable antenna

Abstract

Reconfigurable Antenna This description relates to an antenna (200) comprising: – an amplifier array (201) comprising a plurality of first elementary cells (203); – a transmitter array (105) comprising a plurality of second elementary cells (107); and – at least one source (101), wherein said at least one source (101) is configured to radiate, or to be irradiated, by the transmitter array (105), and the amplifier array (201) is configured to radiate and to be irradiated by the transmitter array (105). Figure for the abbreviation: Fig. 2

Description

Title of the invention: Reconfigurable antenna Technical field

[0001] The present description relates generally to electronic devices, more particularly to reconfigurable antennas. Prior art

[0002] Compared to traditional antennas, reconfigurable antennas can have improved gain and provide access to additional functionalities, for example electronic depointing or emission of multiple, pinched or shaped beams. This benefits the development of numerous applications, such as radar systems, detection systems and communication systems from the C band (from approximately 4 to 8 GHz) to the D band (from approximately 110 to 170 GHz). The use of reconfigurable antennas is also envisaged in a frequency band located around 300 GHz.

[0003] Multiple fields of application are likely to benefit from reconfigurable antennas, including: - automotive radars for assistance and / or driving assistance, for example for active safety purposes; - very high resolution imaging and surveillance systems; - very high-speed millimeter wave communication systems, for example for inter- or intra-building communications in a home or building automation environment; - antennas for space applications, for example, Ka-band LEO (Low Earth Orbit) ground-satellite telemetry links, reflector antennas dedicated to satellite communications with reconfigurable primary feed, satellite on the move (SOTM) telecommunications systems, Internet access devices or systems, television broadcasting devices or systems, etc.; and - point-to-point and point-to-multipoint communication systems such as metropolitan area networks, fronthaul and backhaul systems for cellular networks, radio access for 5G mobile networks, etc.

[0004] Among the existing high-gain antennas, reflector antennas have in particular been proposed. These antennas are however complex and expensive to produce because the reflectors require, particularly for high-frequency applications, a very precise curvature. In addition, motors are used to direct the beam in the direction desired. Phased array antennas have been proposed to allow electronic beam control. However, these antennas are expensive to develop and produce, particularly since they include amplification modules to compensate for losses induced by phase shift circuits.

[0005] Other reconfigurable antennas with depointing and / or beamforming have also been proposed. Among these antennas, there are in particular transmit array antennas (transmitarray antennas), also called discrete lens antennas. Existing transmit array antennas generally comprise a radiating panel comprising reconfigurable elementary cells, or transmitting cells. Each elementary cell of the radiating panel comprises a first antenna element irradiated by an electromagnetic field emitted by one or more focal sources, a second antenna element transmitting a modified signal to the outside of the antenna, and a coupling element between the first and second antenna elements.The elementary cells are intended to control an electromagnetic field distribution in the vicinity of a radiating aperture of the antenna, thus making it possible to produce one or more beams in a given direction or to synthesize a beam with a defined template. In an ideal case, each elementary cell is capable of compensating for each path difference between the focal source(s) and the radiating aperture. In practice, in order to simplify the antenna, the elementary cells can only compensate for a limited number of phase states, for example 2N phase states, with N a positive integer, in the case of N-bit phase quantization compensation. The same transmitter network can alternate between transmission and reception phases, provided that it is devoid of non-reciprocal elements such as amplifiers or attenuators.Otherwise, the transmitting network can only operate in transmission or reception.

[0006] However, transmitting array antennas suffer from various drawbacks. In particular, existing transmitting array antennas have a relatively large thickness, imposed by a need to distance the focal source(s) from the transmitting array. Summary of the invention

[0007] It would be desirable to overcome all or part of the disadvantages of existing reconfigurable antennas. More particularly, there is a need to have reconfigurable antennas having improved performance, reduced energy consumption and smaller size compared to existing reconfigurable antennas, in order, for example, to meet the needs of applications such as communication satellites (SATCOM).

[0008] For this, one embodiment provides an antenna comprising: - an amplifier network comprising a plurality of first elementary cells; - a transmitter network comprising a plurality of second elementary cells; and - at least one source, wherein said at least one source is configured to irradiate, or to be irradiated, by the transmitter network, and the amplifier network is configured to irradiate and to be irradiated by the transmitter network.

[0009] According to one embodiment, each first elementary cell comprises at least one first antenna element located opposite the transmitter network.

[0010] According to one embodiment, each first elementary cell further comprises at least one amplifier connected to said at least one first antenna element.

[0011] According to one embodiment, each first elementary cell comprises: - a first amplifier, preferably a power amplifier, intended to amplify a signal emitted by the antenna; - a second amplifier, preferably a low noise amplifier, intended to amplify a signal received by the antenna; and - switches configured to activate the first or second amplifier depending on a control signal.

[0012] According to one embodiment, each second elementary cell comprises a second antenna element intended to reflect, in the direction of the amplifier network, a signal coming from said at least one source and / or to reflect, in the direction of said at least one source, a signal coming from the amplifier network.

[0013] According to one embodiment, the second antenna elements are located opposite the amplifier network and said at least one source.

[0014] According to one embodiment, each second elementary cell comprises a third antenna element connected to the second antenna element by a phase shift circuit.

[0015] According to one embodiment, each first cell is adapted to operate a polarization rotation.

[0016] According to one embodiment, said at least one source is a single horn antenna.

[0017] According to one embodiment, the antenna comprises fewer first elementary cells than second elementary cells, preferably four times fewer first elementary cells than second elementary cells. Brief description of the drawings

[0018] These characteristics and advantages, as well as others, will be explained in detail in the following description of particular embodiments given without limitation in relation to the attached figures among which:

[0019] [Fig.l] is a schematic and partial side view of an example of a transmitting array antenna;

[0020] [Fig.2] is a schematic and partial side view of a reconfigurable antenna according to one embodiment; and

[0021] [Fig.3] is a detail view of part of the antenna of [Fig.2]. Description of the embodiments

[0022] The same elements have been designated by the same references in the different figures. In particular, the structural and / or functional elements common to the different embodiments may have the same references and may have identical structural, dimensional and material properties.

[0023] For the sake of clarity, only the steps and elements useful for understanding the described embodiments have been shown and are detailed. In particular, the manufacturing methods of the described transmitter networks will not be detailed, the production of the described structures being within the reach of the person skilled in the art from the indications of the present description, for example by implementing standard printed circuit manufacturing techniques.

[0024] Unless otherwise specified, when referring to two elements connected to each other, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") to each other, this means that these two elements can be connected or be connected by means of one or more other elements.

[0025] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "upper", "lower", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0026] Unless otherwise specified, the expressions “about”, “approximately”, “substantially”, and “of the order of” mean to within 10%, preferably to within 5%.

[0027] In the following description, the terms “insulator” and “conductor” mean respectively, unless otherwise specified, electrically insulating and electrically conductive.

[0028] [Fig.l] is a schematic and partial side view of an example of antenna 100 transmitarray antenna.

[0029] The antenna 100 typically comprises one or more primary sources 101 (a single source 101, in the example shown) irradiating a transmitting network 105. The source 101 may have any polarization, for example linear or circular. The network 105 comprises a plurality of elementary cells 107, for example arranged in a matrix according to rows and columns. Each cell 107 typically comprises a first antenna element 107a, located on the side of a first face of the network 105 arranged opposite the primary source 101, and a second antenna element 107b, located on the side of a second face of the network opposite the first face. The second face of the network 105 is for example turned towards a transmission medium, or external medium, of the antenna 100.

[0030] Each cell 107 is capable, in transmission, of receiving electromagnetic radiation on its first antenna element 107a and of re-emitting this radiation from its second antenna element 107b, for example by introducing a known phase shift ¢). In reception, each cell 107 is capable of receiving electromagnetic radiation on its second antenna element 107b and of re-emitting this radiation from its first antenna element 107a, in the direction of the source 101, with the same phase shift ¢. The radiation re-emitted by the first antenna element 107a is for example focused on the source 101.

[0031] The characteristics of the near-field or far-field radiation produced by the antenna 100, in particular its shape (or size), its intensity and its maximum emission direction (or pointing direction), depend on the values ​​of the phase shifts respectively introduced by the different cells 107 of the network 105.

[0032] Transmitting array antennas have the advantage, among other things, of being energy efficient and relatively simple, inexpensive and compact. This is due in particular to the fact that the transmitting arrays can be produced using planar technology, generally on a printed circuit.

[0033] The present description relates more particularly to antennas with a reconfigurable transmitter array 105 and a fixed beam. The transmitter array 105 is said to be reconfigurable when the elementary cells 107 are electronically controllable individually to modify their phase shift value ¢) and / or their amplitude, which makes it possible to dynamically modify the characteristics of the radiation generated by the antenna, and in particular to modify its pointing direction without mechanically moving the antenna or a part of the antenna by means of a motorized element.

[0034] In the illustrated example, the primary source 101 is connected to a circuit 109. The circuit 109 is for example a transmission and / or reception circuit intended respectively to produce signals to be transmitted by the reconfigurable antenna 100 and / or to process signals received by the reconfigurable antenna 100. This example is however not not limiting, the circuit 109 being further able to implement additional functions such as analog-digital conversion functions, filtering, impedance adaptation, interference elimination, etc.

[0035] [Fig. 2] is a schematic and partial side view of a reconfigurable antenna 200 according to one embodiment. The antenna 200 of [Fig. 2] comprises elements in common with the antenna 100 of [Fig. 1]. These common elements will not be detailed again below.

[0036] The reconfigurable antenna 200 of [Fig. 2] differs from the reconfigurable antenna 100 of [Fig. 1] in that the reconfigurable antenna 200 further comprises an amplifier network 201 comprising a plurality of elementary cells 203. The amplifier network 201 is preferably positioned in a near-field region of the transmitter network 105.

[0037] According to one embodiment, the source 101 is configured to irradiate, or to be irradiated, by the transmitter network 105, and the amplifier network 201 is configured to irradiate and to be irradiated by the transmitter network 105.

[0038] The elementary cells 203 of the amplifier network 201 are for example arranged in a matrix according to rows and columns. Furthermore, the elementary cells 203 are for example substantially located in the same plane, the network 201 being in this case of the planar type. Each elementary cell 203 comprises at least one antenna element 203b (two antenna elements 203b, in the example shown) located on the side of a face of the amplifier network 201 arranged opposite the transmitter network 105. Each elementary cell 203 further comprises an amplification circuit 205 (symbolized, in [Fig. 2], by a square) connected to the antenna element or elements 203b of the cell. By way of example, the amplifier network 201 is produced using planar technology, for example on a printed circuit board.

[0039] The amplifier network 201 of the reconfigurable antenna 200 comprises, for example, a number of antenna elements 203b equal to the number of first antenna elements 107a of the transmitter network 105, each antenna element 203b of the amplifier network 201 being, for example, located opposite one of the first antenna elements 107a of the transmitter network 105. However, this example is not limiting and the amplifier network 201 may, as a variant, comprise a number of antenna elements 203b strictly less than or strictly greater than the number of first antenna elements 107a of the transmitter network 105.

[0040] The elementary cells 107 of the transmitter network 105 are for example substantially located in the same plane, for example a plane substantially parallel to the plane of the amplifier network 201. Each elementary cell 107 of the transmitter network 105 is for example separated from the adjacent elementary cells 107 by a distance equal to approximately half a central emission wavelength and / or antenna reception 200.

[0041] In the example shown, the reconfigurable antenna 200 comprises a number of elementary cells 203 strictly less than the number of elementary cells 107. This example is however not limiting, the reconfigurable antenna 200 being able, as a variant, to comprise a number of elementary cells 203 equal to or strictly greater than the number of elementary cells 107. By way of example, the reconfigurable antenna 200 comprises four, nine or sixteen times fewer amplification circuits 205 than elementary cells 107, each elementary cell 203 then comprising for example respectively four, nine or sixteen antenna elements 203b.

[0042] Although only two elementary cells 203 and five elementary cells 107 have been shown in [Fig.2], the reconfigurable antenna 200 can of course comprise numbers of elementary cells 203 and elementary cells 107 different from those shown, for example several tens, several hundreds or several thousands of elementary cells 203 and elementary cells 105.

[0043] [Fig. 2] illustrates more particularly a case in which the reconfigurable antenna 200 operates in transmission. In this case, the source 101 irradiates the transmitter network 105, each cell 107 of which is capable of receiving electromagnetic radiation coming from the source 101 on its first antenna element 107a, and of re-emitting this radiation from its first antenna element 107a in the direction of the amplifier network 201. In transmission, the first antenna element 107a makes it possible to reflect the electromagnetic radiation coming from the source 101 in the direction of the elementary cells 203 of the amplifier network 201. The first antenna elements 107a of the elementary cells 107 have, for example, for this purpose, a polarization substantially orthogonal to the polarization of the source 101.For example, the second antenna elements 107b of the elementary cells 107 have a linear polarization parallel or orthogonal to the polarization of the first elementary cells 107a. As a variant, the second antenna elements 107b of the elementary cells 107 have a circular polarization.

[0044] In transmission, each elementary cell 203 of the amplifier network 201 is capable of receiving, on its antenna element 203b or one of its antenna elements 203b, electromagnetic radiation originating from the reflection, on the first antenna elements 107a of the elementary cells 107 of the transmitter network 105, and of emitting, from its antenna element 203b or another of its antenna elements 203b, amplified electromagnetic radiation of modified polarization in the direction of the transmitter network 105. The elementary cells 203 are for example adapted to operate a polarization rotation, for example of the order of 90°, between the received radiation and the re-emitted radiation. In this case, the electromagnetic radiation re-emitted by the elementary cells 203 of the amplifier network 201 has for example a polarization substantially parallel to that of the first antenna elements 107a of the elementary cells 107 of the transmitter network 105. Each cell 107 is capable, in transmission, of receiving, on its first antenna element 107a, electromagnetic radiation coming from the amplifier network 201 and of re-emitting this radiation, from its second antenna element 107b, for example by introducing a known phase shift ¢).

[0045] The characteristics of the near-field or far-field radiation produced by the antenna 200, in particular its shape (or size), its intensity and its maximum emission direction (or pointing direction), depend on the values ​​of the phase shifts respectively introduced by the different elementary cells 107 of the transmitter network 105.

[0046] Although this has not been shown, the reconfigurable antenna 200 can, as a variant, operate in reception. In this case, each elementary cell 107 of the transmitter network 105 is capable of receiving, on its second antenna element 107b, electromagnetic radiation coming from the external environment and of re-emitting this radiation, from its first antenna element 107a, in the direction of the elementary cells 203 of the amplifier network 201, with the phase shift ¢. In reception, each elementary cell 203 of the amplifier network 201 is capable of receiving, on its antenna element 203b or one of its antenna elements 203b, electromagnetic radiation coming from the transmitter network 105 and of emitting, from its antenna element 203b or another of its antenna elements 203b, amplified electromagnetic radiation of modified polarization in the direction of the transmitter network 105.The electromagnetic radiation re-emitted by the elementary cells 203 of the amplifier network 201 has, for example, a polarization substantially orthogonal to that of the first antenna elements 107a of the elementary cells 107 of the transmitter network 105. In this case, each cell 107 is capable of receiving electromagnetic radiation coming from the amplifier network 201 on its first antenna element 107a, and of re-emitting this radiation from its first antenna element 107a. On reception, the first antenna element 107a makes it possible, for example, to reflect the electromagnetic radiation coming from the amplifier network 201 in the direction of the source 101.

[0047] Each elementary cell 107 comprises for example a phase shift circuit of which a first terminal is connected to the first antenna element 107a, located opposite the source 101 and towards the amplifier network 201, and of which a second terminal is connected to the second antenna element 107b, facing the external environment. The phase shift circuit is for example configured to apply a phase shift ¢) between the signal received by the antenna element 107a and the signal transmitted by the antenna element 107b, in the case where the reconfigurable antenna 200 operates in transmission, or for apply the phase shift ¢) between the signal received by the antenna element 107b and the signal transmitted by the antenna element 107a, in the case where the reconfigurable antenna 200 operates in reception.

[0048] [Fig. 2] illustrates an example in which each elementary cell 107 is configured to introduce a phase shift ¢) between the signals received or transmitted by the antenna element 107a and the signals transmitted or received by the antenna element 107b. This example is however not limiting, the elementary cell being able, as a variant or as a complement, to implement other functions, for example a polarization state change function making it possible to switch from a signal having a left circular polarization to a signal having a right circular polarization. By way of example, each elementary cell 107 of the reconfigurable transmitter network 105 has a structure identical or analogous to the elementary cell of the transmitter network described in the patent application EP 4117117, the cell then being for example adapted to switch between two polarization states and four phase states.

[0049] [Fig. 3] is a detailed view of a portion of the reconfigurable antenna 200 of [Fig. 2]. [Fig. 3] is more precisely an equivalent electrical diagram of one of the elementary cells 203 of the amplifier network 201.

[0050] In the example shown, the elementary cell 203 comprises a switch 301, for example a single pole double throw (SPDT) switch. In this example, the switch 301 more precisely comprises an input connected to a circuit 303, a first output connected to an input of a first amplifier 305 (PA), and a second output connected to an output of a second amplifier 307 (LNA). The switch 301 receives, for example, a control signal to connect its input to its first output, when the reconfigurable antenna 200 is used in transmission, and to its second output, when the reconfigurable antenna 200 is used in reception.

[0051] The amplifier 305 of the elementary cell 203 is for example intended to amplify a signal emitted by the antenna 200. By way of example, the amplifier 305 is a power amplifier, for example a class A linear amplifier in CMOS (Complementary Metal-Oxide-Semiconductor) SOI (Silicon On Insulator) technology, for example of the type described in the article by A. Hamani, A. Siligaris, B. Blampey and JLG Jimenez entitled “167-GHz and 155-GHz High Gain D-band Power Amplifiers in CMOS SOI 45-nm Technology” from the fifteenth “European Microwave Integrated Circuits Conference (EuMIC)” in Utrecht, the Netherlands in 2021, pages 261 to 264.

[0052] The amplifier 307 of the elementary cell 203 is for example intended to amplify a signal received by the antenna 200. For example, the amplifier 307 is a low noise amplifier (LNA). This makes it possible to optimize a noise factor of the elementary cell 203 when it is used for reception. For example, the amplifier 307 comprises a class “AB” amplifier comprising, for example, one or two operating stages. The amplifier 307 has, for example, an electrical power of between 10 and 20 mW.

[0053] In the example shown, the elementary cell 203 comprises another switch 309, for example a single pole double throw (SPDT) switch. In this example, the switch 309 more precisely comprises an input connected to a circuit 311, a first output connected to an output of the first amplifier 305, and a second output connected to an input of the second amplifier 307. The switch 309 receives, for example, a control signal to connect its input to its first output, when the reconfigurable antenna 200 is used in transmission, and to its second output, when the reconfigurable antenna 200 is used in reception.

[0054] By way of example, the circuits 303 and 311 are impedance matching and / or decoupling circuits between radiofrequency signals and low-frequency signals, for example continuous signals.

[0055] In the example shown, the circuits 303 and 311 each comprise a terminal connected to the antenna element 203b. The circuits 303 and 311 are for example connected to different regions of the antenna element 203b. For example, the antenna element 203b is a patch antenna comprising for example a rectangular or square-shaped conductive plane in which a U-shaped slot is formed.

[0056] [Fig. 3] illustrates an example in which the elementary cell 203 comprises the switches 301 and 309 making it possible to activate either the amplifier 305, during transmission phases, or the amplifier 307, during reception phases. This example is however not limiting, each elementary cell 203 of the network 201 being able, as a variant, to be devoid of the switches 301 and 309 and to comprise only a single amplifier, for example the amplifier 305 in a case where the antenna 200 is used exclusively in transmission, or the amplifier 307, in a case where the antenna 200 is used exclusively in reception.

[0057] An advantage of the reconfigurable antenna 200 lies in the fact that the presence of the amplifier network 201 advantageously makes it possible to bring the primary source 101 closer to the transmitter network 105. In other words, this makes it possible to “fold” the source of the antenna 200 compared to the case of the antenna 100. The antenna 200 thus has a thickness that is less, for example of the order of three times less, than that which an antenna with a comparable transmitter network would have, for example the antenna 100. This also provides the advantage, compared to a transmitting array antenna of the antenna 100 type, of facilitating the production of systems for amplifying the transmitted or received radiofrequency signal.

[0058] Although this has not been detailed above in relation to Figures 2 and 3, the source 101 may be connected to an amplification circuit, for example integrated into the circuit 109, the amplification circuit then comprising for example an amplifier similar or identical to the amplifier 305, for use of the antenna 200 in transmission, and / or an amplifier similar or identical to the amplifier 307, for use of the antenna 200 in reception. In a case where the antenna 200 is intended to be able to operate alternately in transmission or reception, one or more switches similar or identical to the switches 301 and 309 may then be provided to activate one or the other amplifier of the amplification circuit.

[0059] Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these various embodiments and variants could be combined, and other variants will occur to those skilled in the art. In particular, those skilled in the art are able to adjust the ratio between the number of elementary cells 203 of the amplifier network 201 and the number of elementary cells 107 of the transmitter network 105 depending on the application, for example depending on the heating produced by each elementary cell 203.

[0060] Furthermore, although this has not been detailed above, the elementary cells 203 of the amplifier network 201 can, in addition to the amplification functions, implement other functions, for example phase shift functions. In this case, the phase shift functions use, for example, varactor or switch structures.

[0061] Finally, the practical implementation of the embodiments and variants described is within the reach of the person skilled in the art from the functional indications given above. In particular, the practical realization of the antenna element(s), the switches and the amplifier(s) of the elementary cells of the amplifier network 201 as well as the practical realization of the elementary cells of the transmitter network 105 are within the reach of the person skilled in the art from the indications of the present description. The person skilled in the art is furthermore capable of adjusting the number of antenna elements 203b of each elementary cell 203 of the amplifier network 201, in particular as a function of the proportion of elementary cells 203 of the amplifier network 201 relative to the elementary cells 107 of the transmitter network 105.

[0062] Furthermore, the elementary cells 107 of the transmitter network 105 can be calibrated in order to correct phase errors linked to the structure of the antenna.

Claims

Claims

1. Antenna (200) comprising: - an amplifier network (201) comprising a plurality of first elementary cells (203); - a transmitter network (105) comprising a plurality of second elementary cells (107); and - at least one source (101), wherein said at least one source (101) is configured to irradiate, or to be irradiated, by the transmitter network (105), and the amplifier network (201) is configured to irradiate and to be irradiated by the transmitter network (105).

2. Antenna (200) according to claim 1, in which each first elementary cell (203) comprises at least one first antenna element (203b) located opposite the transmitter network (105).

3. Antenna (200) according to claim 2, wherein each first elementary cell (203) further comprises at least one amplifier (305, 307) connected to said at least one first antenna element (203b).

4. Antenna (200) according to claim 3, wherein each first elementary cell (203) comprises: - a first amplifier (305), preferably a power amplifier, intended to amplify a signal emitted by the antenna; - a second amplifier (307), preferably a low noise amplifier, intended to amplify a signal received by the antenna; and - switches (301, 309) configured to activate the first or the second amplifier according to a control signal.

5. Antenna (200) according to any one of claims 1 to 4, in which each second elementary cell (107) comprises a second antenna element (107a) intended to reflect, in the direction of the amplifier network (201), a signal coming from said at least one source (101) and / or to reflect, in the direction of said at least one source, a signal coming from the amplifier network.

6. Antenna (200) according to claim 5, wherein the second antenna elements (107a) are located opposite the amplifier network (201) and said at least one source (101).

7. Antenna (200) according to claim 5 or 6, in which each second elementary cell (107) comprises a third element antenna (107b) connected to the second antenna element (107a) by a phase shift circuit.

8. Antenna (200) according to any one of claims 1 to 7, in which each first cell (203) is adapted to operate a polarization rotation.

9. An antenna (200) according to any one of claims 1 to 8, wherein said at least one feed (101) is a single horn antenna.

10. Antenna (200) according to any one of claims 1 to 9, comprising fewer first elementary cells (203) than second elementary cells (107), preferably four times fewer first elementary cells than second elementary cells.

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