Controlled Radiation Antenna System

Abstract

Controlled Radiation Antenna System This description relates to an antenna system comprising a transmitting or receiving antenna element (12), an array of parasitic antenna elements (14) individually associated with reconfigurable loads (15), one or more near-field antennas (32), and a circuit (18, 34) for adjusting the configuration of the array of parasitic antenna elements based on radiation received by the near-field antenna(s) during radio frequency transmission by the transmitting or receiving antenna element. Figure for the abstract: Fig. 1

Description

Title of the invention: Controlled radiation antenna system technical field

[0001] This description relates generally to antenna arrays and more particularly to compact and directional antennas. This description applies more specifically to reconfigurable antenna arrays. Prior art

[0002] Antenna arrays are widely used in radio frequency detection or transmission systems, particularly in telecommunication systems.

[0003] So-called directional or super-directional antennas are based on an array of antenna elements. They are generally made from an array of antenna elements in which the antennas are weighted and configured to focus the beam in a given direction. This can be implemented as a parasitic element architecture (a single antenna, excited by a generator, which is coupled to one or more so-called parasitic antennas, connected under a given load condition) or as an architecture based on the control of the amplitude and phase associated with each element of the antenna array.Parasitic element antenna architectures exploit coupling and interference between different antenna elements to tune the antenna's radiation pattern with a main (useful) lobe in a given direction (unidirectional antenna) and of a given angular width, or several useful lobes in different directions (multidirectional antenna).

[0004] Such antennas are particularly sensitive to their environment, which can cause distortions in the antenna's radiation pattern. This problem is all the more critical when the antenna is small in electrical size (physical size relative to the wavelength). Moreover, the smaller the antenna, the more sensitive it is to disturbances in its immediate environment. For example, in a telecommunications device such as a telephone, such an antenna is sensitive to disturbances caused by hand movements or changes in the user's body position relative to the antenna.

[0005] Antenna array calibration systems have already been proposed which modify the weighting coefficients of the antenna elements according to operating conditions during antenna calibration phases.

[0006] US patent 2015 / 0115978 describes an antenna system in which an array of electro-optical probes distributed within the antenna radome is used in calibration phases during which a separate antenna, dedicated to calibration, transmits. The coefficients associated with each antenna element are adjusted during this calibration phase, based on the signals received by the different antenna elements and back-modulated signals by the electro-optical probes.

[0007] US patent 2016 / 0036127 describes a reconfigurable antenna system in which a frequency-reconfigurable antenna is associated with parasitic emission elements to adjust the directivity. These elements are associated with measurement components for impedance matching and other tuning elements to adjust the radiation pattern. However, these measurements and adjustments do not include feedback for readjusting the loads that control the radiation pattern.

[0008] Known calibration systems are not suitable for real-time adjustment of the radiation pattern, particularly when they require a dedicated emission element for calibration. However, such adjustment would be desirable, especially for antennas sensitive to nearby environmental disturbances.

[0009] Moreover, the precision required for adjusting the amplitude and phase weighting coefficients of the different antenna elements due to the miniaturization of antennas makes indirect measurement solutions (impedance measurement) unsuitable. Summary of the invention

[0010] There is a need for a directional or super-directional transmitting or receiving antenna adapted to be adjusted in real time.

[0011] There is a need for a reconfigurable antenna whose settings are made from direct radiation measurements.

[0012] One embodiment overcomes all or part of the drawbacks of known reconfigurable antenna arrays.

[0013] One embodiment provides an antenna system comprising: - a transmitting or receiving antenna element; - a network of parasitic antenna elements individually associated with reconfigurable loads; - one or more near-field antennas; and - a circuit for adjusting the configuration of the network of parasitic antenna elements according to radiation captured by the antenna(s) in the near field during a radio frequency emission by the transmitting or receiving antenna element.

[0014] According to one embodiment, the circuit is configured to adjust the impedance values ​​of the reconfigurable loads based on a comparison, to reference data, of data representative of a radiation pattern of the system.

[0015] According to one embodiment, the reference data are representative of Radiation diagrams of the system in the presence of disturbances.

[0016] According to one embodiment, the gap between two antenna elements is less than a quarter of the wavelength of the center frequency of the bandwidth for which the network is intended.

[0017] According to one embodiment, the gap between each near-field antenna and the nearest antenna element is less than one-tenth of the wavelength of the center frequency of the bandwidth for which the network is intended.

[0018] According to one embodiment, the system comprises exactly eight parasitic antenna elements equidistant from the transmitting or receiving antenna element and distributed every 45° around said element.

[0019] According to one embodiment, the transmitting or receiving antenna element and the network of parasitic antenna elements individually associated with the reconfigurable loads are part of a reconfigurable antenna element network.

[0020] One embodiment provides a method for configuring the antenna system as described, comprising the following steps: a) identify, from a set of reference data, reference data that are as close as possible to representative data of a radiation pattern of the system; and b) adjust reconfigurable load impedance values ​​according to identified reference data.

[0021] According to one embodiment, the reference data are representative of radiation diagrams of the system in the presence of disturbances.

[0022] According to one embodiment, in step b), the impedance values ​​of the reconfigurable loads are adjusted to reference values ​​associated with the reference data identified in step a).

[0023] According to one embodiment, the method further comprises, prior to step a), a step of recording reference data, said data being representative of radiation patterns of the system in the presence of disturbances. Brief description of the drawings

[0024] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments and implementations, given by way of non-limiting example, in relation to the accompanying figures, among which:

[0025] Fig. 1 represents, in a very schematic way, one embodiment of an antenna system;

[0026] [Fig.2] is a schematic perspective view of an embodiment of antenna arrangement in an antenna system of the type of that of [Fig.1];

[0027] [Fig. 3] represents, in a very schematic and block-like manner, an example functional architecture of an antenna system embodiment;

[0028] [Fig.4] represents, in a very schematic way and in block form, a method of implementing a method of controlling the parameters of the antenna elements of an antenna system;

[0029] [Fig.5] illustrates, in a very schematic way and by means of a timing diagram, the implementation of the control of the adjustment of a configurable antenna network;

[0030] [Fig. 6] is a diagram illustrating one method of implementing a learning process; and

[0031] [Fig.7] is a diagram illustrating a method of implementing a method for adjusting, in case of disturbance, a field emitted by the antenna system of [Fig.3]. Description of the implementation methods

[0032] The same elements have been designated by the same reference numerals in the different figures. In particular, the structural and / or functional elements common to the different embodiments and implementation methods may have the same reference numerals and may have identical structural, dimensional and material properties.

[0033] For the sake of clarity, only the steps and elements useful for understanding the described embodiments and implementation methods have been shown and are detailed. In particular, applications that could implement the reconfigurable antenna arrays of this description are not detailed, as the described embodiments and implementation methods are compatible with common applications using reconfigurable antenna arrays.

[0034] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements connected (in English "coupled") together, this means that these two elements can be connected or linked through one or more other elements.

[0035] 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", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0036] Unless otherwise specified, the expressions "approximately", "roughly", and "in the order of" mean within 10%, preferably within 5%.

[0037] According to the embodiments and implementation methods described, it is planned to associate, with a network of antenna elements constituting a directional antenna figurable, elements for measuring near-field radiation around the antenna array.

[0038] Reconfigurable super directional antennas can be divided into three categories according to the nature of the system regulating the directivity.

[0039] A first category concerns parasitic element antennas, in which only one of the antenna array elements is active (i.e., excited by the radio frequency signal to be transmitted, or useful signal, and / or connected to a detector of the received radiation) while the other array elements are loaded with impedances calculated to give the active element a desired radiation lobe. Typically, the secondary antenna elements are associated with loads having impedances determined according to the desired parasitic contributions to the main antenna element in order to focus the main antenna lobe in the desired direction.

[0040] A second category concerns antennas consisting of a digital phased array, in which each antenna element is connected to a radio frequency transmit-receive chain. Individual amplitude and phase weighting coefficients are assigned to each baseband antenna element (upstream of the amplifier and phase shifter of each antenna) so that the array exhibits the desired directivity.

[0041] A third category concerns antennas consisting of an analog phased array in which, as with the digital phased array, each antenna element transmits and / or receives a portion of the useful signal. However, in the case of analog phased array antennas, the power division and the amplitude and phase weightings applied to each element are performed at the level of each antenna element, by adjusting the amplifier and phase shifter associated with it.

[0042] The diameter of the antenna array is said to be "compact" if the radial spacing between the central element and the parasitic elements is less than 0.25X (lambda), where lambda represents the wavelength of the center frequency of the operating frequency band of the antenna array.

[0043] In the following description, we will take as an example an antenna array according to the first category, that is to say an array in which only one of the antenna elements is active by being connected to the radio frequency transmitter and transmits or interprets the useful signal.

[0044] Fig. 1 represents, in a very schematic way, an embodiment of a radio frequency transmission antenna system.

[0045] This system comprises an array 1 of antenna elements geometrically distributed in space. Taking the example of an array with a single active element, the array 1 It comprises a transmitting element or antenna 12 and several elements or antennas 14 distributed around the element 12. To create a superdirectional antenna, the elements 12 and 14 are preferably arranged relative to each other with inter-element distances between 0.5 and 0.2, more preferably between 0.25 and 0.5, where λ (lambda) represents the wavelength of the center frequency of the antenna's operating frequency band. In other words, the spacing between any two antenna elements 12, 14 of the array 1 is less than half, preferably less than a quarter, of the wavelength λ of the center frequency of the bandwidth for which the array is intended.

[0046] According to a preferred embodiment, the elements 14 are preferably substantially equidistant from the element 12 and distributed regularly around the element 12. The elements 14 are, for example, located on the periphery of a circle centered on the element 12 and distributed at regular intervals around the periphery of this circle. The array 1 preferably comprises eight elements 14 equidistant from the element 12. In this case, the elements 14 are distributed every 45° around the element 12.

[0047] The transmitting element 12 is connected, preferably via an impedance matching network 122 (Impedance Matching), to an electronic transmitting circuit 16 (Tx). Conventional components (not shown) transmit radio frequency signals to the circuit 16, depending on the application. In the embodiments specifically addressed in this description, the center frequency of the transmitting frequency band is on the order of gigahertz, preferably with a value between 100 MHz and 7 GHz.

[0048] Each parasitic element 14 is associated with a configurable load 15, preferably made up of switchable passive components to form impedances of variable values. In the example of [Fig. 1], each configurable load 15 is represented by three impedances 151, 153, and 155, connected on one side to ground and, on the other side, individually to a selector 157 for connecting one of the impedances 151, 153, and 155 to the associated parasitic antenna element 14. Although three impedances 151, 153, and 155 are shown in [Fig. 1] for each configurable load 15, it is clear that each configurable load 15 can have any number of impedances. Each selector 157 can be individually controlled from a digital electronic circuit 18 (Control) for center frequency control and beam direction.

[0049] This is only one example, and any common configurable parasitic load structure can be used. In particular, a variant can be provided in which the impedances 151, 153, and 155 of all or part of the configurable loads 15 are replaced by a single component with a variable impedance. The selector 157 can then be omitted, the variable impedance component being connected in this case. on the one hand to the mass and, on the other hand, directly to the element 14 which is associated with it.

[0050] The architecture described so far in relation to [Fig.1] can be replaced by any reconfigurable antenna array system, whether it has parasitic elements or a phased array of several active antenna elements.

[0051] According to the embodiments described, a device 3 comprising one or more near-field antennas 32 for measuring the radiation emitted by the array 1 is planned to be associated with the network 1 of reconfigurable antenna elements. Each near-field antenna 32 is connected to an electronic circuit 34 (Evaluation) for evaluating the near-field radiation.

[0052] The results provided by the near-field radiation measurements are interpreted by circuit 34 to provide circuit 18 with adjustment parameters for the various loads 15. This creates a feedback loop to control the radiation of the antenna array based on desired radiation parameters (radiation pattern). In a practical implementation, circuits 18 and 34 can be combined and include a microcontroller for implementing a program or algorithm to interpret the measurements of the signals captured by the antennas 32 and to determine the parameters of the loads 15.

[0053] By "near field" is meant a measurement of the electromagnetic field carried out at a very small distance (on the order of ten to twenty times smaller) from the wavelength X corresponding to the center frequency of the bandwidth for which the network is intended. This distance corresponds, for example, to the spacing between the antenna elements 14 associated with the configurable loads 15 to form the beam. Typically, the reactive zone around an antenna, that is to say its sensitivity to the presence of disturbing elements such as a hand, is considered to be on the order of X / 2ir, or about 7J6. Thus, according to a preferred embodiment, each antenna 32 is arranged at a maximum distance of about X / 10 from the nearest antenna element 12 or 14.In other words, the distance between each near-field antenna and the nearest antenna element 12 or 14 of the array 1 is less than one-tenth of the wavelength of the center frequency of the bandwidth for which the array is intended. The probes or antennas 32 can be arranged uniformly or non-uniformly around the antenna system, for example, depending on the type of radiation to be sampled.

[0054] By way of a specific embodiment, for an antenna system adapted to an operating frequency on the order of gigahertz, the antenna elements 12 and 14 of the antenna array 1 are spaced from each other by a maximum distance on the order of a few (less than 10) centimeters. The antennas 32 are respectively spaced from the nearest antenna element 12 or 14 by a distance of approximately a few millimeters to a few centimeters.

[0055] According to the described embodiments, the respective distances between the antennas 12, 14, and 32 are fixed. Thus, even if the antennas 32 have an impact on the radiation pattern of the system, it is easy to take these parameters into account in the algorithm for analyzing the radiation captured by the near-field antennas 32.

[0056] Preferably, in an antenna array with passive parasitic elements, the number of antennas 32 is less than or equal to the number of parasitic antenna elements 14 and each antenna 32 is associated with a parasitic antenna element 14. In an antenna array with active or reconfigurable parasitic elements, the number of antennas 32 is preferably equal to the number of antenna elements 12 and 14 of the array 1.

[0057] [Fig.2] is a schematic perspective view of an embodiment of antenna arrangement in an antenna system of the type of that in [Fig.1].

[0058] According to this embodiment, between four and twelve (twelve in the representation of [Fig. 2]) antenna elements 14 are provided, distributed in a first group of six antenna elements 141 and a second group of six antenna elements 142, arranged on two concentric circles around the antenna element 12. A number of antennas 32 is also provided, depending on the number of antenna elements 141 or 142, for example between four and twelve (six in the representation of [Fig. 2]). The antennas 32 are distributed on a third concentric circle outside the circles of elements 141 and 142.

[0059] Fig. 3 represents, in a very schematic way and in block form, an example of the functional architecture of an embodiment of an antenna system.

[0060] This figure illustrates the main elements of the interacting antenna system.

[0061] We find: - the electronic transmission circuit 16 (Radio frequency transmitter) connected to the transmission antenna 12 (Transmission antenna); - a 1415 network (Reconfigurable parasitic network) of reconfigurable parasitic elements (elements 14 and loads 15, [Fig.l]); - a network of antennas or near-field probes 32 (Probes); and - electronic circuits 1834 (Processing Unit) fulfilling, among other things, the functions of interpreting the measurements of the signals captured by the antennas 32 and determining the parameters of the network loads 1415.

[0062] In the example shown, the system further comprises a memory 20 (Memory). The memory 20 includes, for example, at least one non-volatile storage memory region and at least one other volatile storage memory region.

[0063] The system may also include one or more other elements. These elements are symbolized, in [Fig.2], by a functional block 22 (FCT).

[0064] As illustrated in [Fig.3], the antenna 12, the elements 14 of the parasitic network 1415 and the probes 32 are in an electromagnetic coupling relationship (EM Coupling).

[0065] Fig. 4 represents, in a very schematic way and in block form, a method of implementing a method of controlling the parameters of the antenna elements 14 of the array 1 on setpoint values ​​(REF) for a given radiation pattern of the array 1.

[0066] When the antenna system enters a transmission mode (block 52, Transmission), circuit 16 is activated and generates a radio frequency signal (block 54, Signal Generation). This is followed by far-field transmission (block 56, Far Field) by the array according to a radiation pattern conditioned by the parameters of the parasitic antennas 14. Far field is understood to mean at a distance from the system greater than ten meters.

[0067] In parallel, the electromagnetic field emitted in the immediate vicinity of the network 1 is captured (block 72, Near-field detection) by the antennas 32, and the measured signals are sent by them to the circuit 34. The circuit 34 then performs an analysis (block 74, Analysis) of these signals with respect to reference or setpoint values ​​(REF). If the signals measured by the antennas 32 differ from the reference values, the circuit 34 commands (block 76, Parameters), via the circuit 18, the reconfiguration of the load impedances 151, 153, and 155 connected to the antenna elements 14.

[0068] Modifying the parameters of the parasitic antennas 14, or their immediate context, is immediate and therefore modifies the radiation pattern of system 1. The detection 72, analysis 74, and tuning 76 steps are preferably performed in a loop (feeding back the output of block 76 to the input of block 72) as long as the network 1 is transmitting. Thus, it is possible to predict, at the level of the analysis algorithm and the determination of the control parameters of the configurable loads 151, 153, and 155, results in the form of progressive increases or decreases in the impedance of each configurable load.

[0069] Fig. 5 illustrates, in a very schematic way and by means of a timing diagram, the implementation of the control of the adjustment of a reconfigurable antenna network.

[0070] This figure represents, in a simplified manner, an example of a perturbation of a main emission lobe relative to a setpoint or reference level REF (Reference Directivity (REF)). Assuming the arrival of a perturbation p (Perturbation (p)), for example, the movement of a hand, in the system's environment, this perturbation p results in a distortion of the radiation pattern of the array 1, or of the lobe direction, or even of the directivity (Directivity in the direction of use (dBi)). The implementation of the measurement (Detection) and analysis steps of the radiation captured by the near-field antennas 32 corrects (Convergence Loop) this drift by modifying the parameters of the reconfigurable array (the loads 151, 153, and 155) of antennas 1 until the direction is restored. reference REF.

[0071] The number of measurement points for near-field radiation, and therefore of antennas 32, depends on the application and, in particular, on the desired resolution or fineness in the number of disturbance situations to be characterized.

[0072] One advantage of the described system lies in the fact that it allows real-time control of the transmitting antenna array. Indeed, the measurements of the signals captured by the antennas 32 of the device 3, as well as the analysis and interpretation performed by the circuit 34, do not require any specific intervention from the transmitting system. It is sufficient for the system to transmit.

[0073] Another advantage is that real-time control also makes it possible to compensate for possible variations in the radiation pattern due to changes in operating conditions such as temperature.

[0074] Compared to an optical probe system, an advantage of the described system is that it does not require emission by a specific antenna.

[0075] However, although the described system is particularly effective for tuning a transmitting antenna array, it can alternatively be implemented for a receiving antenna array. In this case, a periodic operating phase is provided during which the system switches to transmitting a signal through the antenna array 1. Preferably, so as not to disrupt reception, such a transmission and tuning phase is carried out with a duty cycle (duration of the transmission phase relative to its periodicity) of less than 10%, preferably less than 1%, i.e., for example, for 1 ms every 100 ms.

[0076] An antenna system as described is particularly advantageous in applications such as antenna network diagnostics, RFID-type radio frequency communications applications using miniature multi-standard readers, electromagnetic compatibility measurement equipment applications or test chamber antennas, miniature directional radars, compact super-directional antennas, etc.

[0077] Figure 6 is a diagram illustrating one way of implementing a learning process. As an example, a non-volatile storage memory region of memory 20 (Fig. 3) stores program code instructions which, when executed by the processing unit 1834, enable the implementation of this process.

[0078] In a first step (block 81, Controlling the antenna to obtain a Di radiation pattern), the antenna 12 ([Fig. 1]) is controlled so that the array 1 emits an electromagnetic field exhibiting a Di radiation pattern. The Di pattern corresponds, for example, to a situation in which the field emission by the array 1 is not subject to any disturbance.

[0079] In a second step (block 82, Cause a disturbance in the field emitted by the antenna), subsequent to the first step 81, a disturbance in the electromagnetic field radiated by the array 1 is intentionally caused. This disturbance is caused, for example, by placing an object, a hand, etc., in close proximity, for example at a distance of a few centimeters or tens of centimeters, to the array 1.

[0080] In a third step (block 83, Evaluating a Dp radiation pattern of the antenna subjected to the disturbance), subsequent to the second step 82, a Dp radiation pattern emitted by the array 1 is evaluated. The Dp pattern, resulting from a modification of the Di pattern caused by the introduction of the disturbance in the previous step, is evaluated, for example, as described previously in relation to step 74 of the process in [Fig. 4]. Representative data of the Dp pattern are obtained, in particular, using the antennas 32 of the system 3. This data is, for example, temporarily stored in a volatile storage memory region of the memory 20.

[0081] In a fourth step (block 84, Adjusting the impedance values ​​of the parasitic loads in order to restore the Di diagram), subsequent to the third step 83, the reconfiguration of the load impedances 151, 153 and 155 connected to the antenna elements 14 is controlled via circuit 18 so as to restore, or get as close as possible to, the Di diagram. In other words, the aim is to reconfigure the array 1 so that, despite the presence of the disturbance, it emits an electromagnetic field with a radiation pattern as close as possible to the Di diagram radiated by the array 1 in the absence of disturbances.

[0082] In a fifth step (block 85, Recording the impedance values ​​enabling the reconstruction of the Di diagram from the Dp diagram), subsequent to the fourth step 84, the parameters enabling the reconstruction of the Di radiation diagram when the Dp radiation diagram is detected by the antennas 32 of the device 3 are recorded or stored. The parameters are stored, for example, in a non-volatile memory storage region of the memory 20.

[0083] In a sixth step (block 86, Stop the disturbance and apply the impedance values ​​to obtain the Di diagram in the absence of disturbances), subsequent to the fifth step 85, the disturbance is removed (for example, the object, hand, etc. is moved away from the grating 1) and the parameters for obtaining the radiation Di diagram in the absence of disturbances are applied. For this purpose, parameters identical to those of the first step 81 are applied, for example.

[0084] Steps 81 to 86 of the process are repeated, for example, by varying the type of disturbance, the position of the disturbing element (object, hand, etc.) relative to the grating 1, the desired radiation pattern Di, etc. In general, We seek to apply disturbances representative of situations likely to occur during the use of network 1. We thus constitute, for example, in the memory 20 of the system, a correspondence table between on the one hand reference data representative of the radiation diagrams of network 1 when it is subjected to different disturbances and, on the other hand, parameters, or reference impedance values, allowing us to restore or approach the Di diagram in the absence of disturbances.

[0085] As an alternative, it may be provided that all or part of the data representing the radiation patterns and the parameters stored in the memory 20 of the system are obtained by simulation, for example by simulating an impact of different disturbances on the radiation pattern of the network 1 and then determining, by calculation, correction parameters allowing us to return to the pattern Di for each of these disturbances.

[0086] Figure 7 is a diagram illustrating an implementation method for adjusting, in the event of a disturbance, a field emitted by the antenna system of Figure 3. As an example, a non-volatile storage memory region of memory 20 (Figure 3) stores program code instructions which, when executed by the processing unit 1834, enable the implementation of this method.

[0087] In a first step (block 91, Controlling the antenna to obtain the radiation pattern Di), the antenna 12 ([Fig. 1]) is controlled so that the array 1 emits an electromagnetic field exhibiting the radiation pattern Di previously described in relation to [Fig. 6]. The pattern Di corresponds, for example, to a situation in which the field emission by the array 1 is not subject to any disturbance.

[0088] In a second step (block 92, In case of disturbance, evaluate the Dp radiation pattern of the antenna subjected to the disturbance), subsequent to the first step 91, a case is considered where the array 1 is subjected to a disturbance. The array 1 then emits an electromagnetic field exhibiting the Dp radiation pattern. For simplicity, the case is considered where the disturbance present in step 92 is similar to the disturbance intentionally applied in step 82 of the process in [Fig. 6], and where the Dp pattern of step 92 corresponds to the Dp pattern of step 83 of [Fig. 6]. However, the steps below are readily adaptable by a person skilled in the art to a case where the disturbance is different from that of step 82 and where the Dp pattern is different from that of step 83.

[0089] In a third step (block 93, Identify a Dk radiation pattern closely resembling the Dp pattern), subsequent to the second step 92, a Dk radiation pattern identical to, or as close as possible to, the Dp pattern is searched for and identified. As an example, the processing unit 1834 scans the contents of the memory 20 searches for representative data of the Dk diagram that most closely approximate the representative data of the Dp diagram. The Dk diagram is, for example, part of a set of radiation diagrams previously recorded in the system's memory 20, for example during the implementation of the process in [Fig.6] for different disturbances, to which correspond impedance values ​​of the loads 15 of the network 1.

[0090] In a fourth step (block 94, Applying impedance values ​​enabling the restoration of the Di diagram from the Dk diagram), subsequent to the third step 93, the parameters (impedance values) are applied which, when the radiation Dk diagram is detected by the system 3, enable the restoration of the Di diagram or its closest approximation to the Di diagram. These parameters associated with the Dk diagram have, for example, been previously stored in the system's memory 20 during the implementation of the process in [Fig. 6] in the case of a disturbance leading to the Dk diagram.

[0091] In a fifth step (block 95, Once the disturbance has ended, apply the impedance values ​​to obtain the Di diagram in the absence of disturbances), subsequent to the fourth step 94, it is assumed that the disturbance has disappeared (for example, the object, the hand, etc., has moved away from the grating 1). The parameters for obtaining the radiation Di diagram in the absence of disturbances are then applied. To do this, for example, parameters identical to those of the first step 91 are applied.

[0092] One advantage of the methods described above in relation to Figures 6 and 7 is that they allow for a reduction in the adaptation time of network 1 in the event of a disturbance. This results in improved transmission and / or reception capacity by network 1 despite the presence of disturbances.

[0093] Various embodiments and variations have been described. Those skilled in the art will understand that certain features of these various embodiments and variations could be combined, and other variations will be apparent to those skilled in the art. In particular, the dimensions of the system and the spacing between antennas depend on the application and especially on the system frequency. Similarly, the number of antenna elements 12, 14 of array 1 and the number of antennas 32 of device 3 depend on the application.

[0094] Furthermore, although it has not been described in detail, adapting the embodiments and implementation methods described to the variant in which the impedances 151, 153 and 155 of all or part of the configurable loads 15 are replaced by a single component having a variable impedance is within the grasp of a person skilled in the art.

[0095] Finally, the practical implementation of the embodiments and variants described is to be completed. The scope of the expert's work is based on the functional specifications given above. In particular, the choice of arrangement for the antenna elements of network 1 and the antennas 32 of device 3 depends on the application. Specifically, the expert is able to arrange the antennas 32 of device 3 to evaluate the emitted field in directions where maximum intensity is desired and / or in directions where minimum, or even virtually zero, intensity is desired.

[0096] Furthermore, adapting the described system to an antenna system in which the array of antenna elements comprises several antennas emitting with amplitude and phase weighting coefficients as a function of the desired radiation pattern is within the reach of a person skilled in the art.

Claims

Claims

1. Antenna system comprising: - a transmitting or receiving antenna element (12); - an array of parasitic antenna elements (14) individually associated with reconfigurable loads (15); - one or more near-field antennas (32); and - a circuit (18, 34) for adjusting the configuration of the array of parasitic antenna elements as a function of radiation picked up by the near-field antenna(s) during radiofrequency transmission by the transmitting or receiving antenna element, wherein the circuit (18, 34) is configured to adjust impedance values ​​of the reconfigurable loads (15) as a function of a comparison, with reference data representative of radiation patterns (Dk) of the system in the presence of disturbances, of data representative of a radiation pattern (Di, Dp) of the system.

2. System according to claim 1, in which the spacing between two antenna elements (12, 14) is less than a quarter of the wavelength of the central frequency of the bandwidth for which the network is intended.

3. A system according to claim 1 or 2, wherein the separation between each near-field antenna and the nearest antenna element (12, 14) is less than one tenth of the wavelength of the center frequency of the bandwidth for which the array is intended.

4. System according to any one of claims 1 to 3, comprising exactly eight parasitic antenna elements (14) equidistant from the transmitting or receiving antenna element (12) and distributed every 45° around said element.

5. System according to any one of claims 1 to 4, in which the transmitting or receiving antenna element (12) and the network of parasitic antenna elements (14) individually associated with the reconfigurable loads (15) are part of a network (1) of reconfigurable antenna elements.

6. Method for configuring the antenna system according to any one of claims 1 to 5, comprising the following steps: a) identifying (93), from a set of reference data, the reference data representative of the diagrams (Dk) of radiation of the system in the presence of disturbances as close as possible to the data representative of the radiation diagram (Di, Dp) of the system; and b) adjusting (94) the impedance values ​​of the reconfigurable loads (15) according to the identified reference data.

7. A method according to claim 6, wherein, in step b), the impedance values ​​of the reconfigurable loads (15) are adjusted to reference values ​​associated with the reference data identified in step a).

8. Method according to claim 6 or 7, further comprising, prior to step a), a step of recording (85) the reference data.

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