Elementary antenna comprising a planar radiating device

Abstract

The invention relates to an elementary antenna comprising a planar radiating device comprising a substantially flat radiating element and an emission and / or reception circuit comprising at least one first type of amplification chain and at least one second type of amplification chain, each first type of amplification chain being coupled to at least one excitation point of a first set of at least one excitation point of the radiating element and each second type of amplification chain being coupled to at least one point of a second set of points, the excitation points of the first and second sets being different and the first type of amplification chain being different from the second type of amplification chain such that they have different amplification properties.

Description

[0001] The present invention relates to the field of network antennas, and in particular active antennas. It is applicable in particular to radars, electronic warfare systems (such as radar detectors and radar jammers), as well as communication systems or other multifunction systems.

[0002] An array antenna comprises a plurality of antennas, which can be planar, meaning printed circuit board-type, often called patch antennas. Planar antenna technology allows for the creation of thin, directional antennas by producing radiating elements through the etching of metallic patterns onto a dielectric layer with a metallic ground plane on its back side. This technology leads to very compact directional electronically scanned antennas that are simpler to manufacture and therefore less expensive than Vivaldi-type antennas.

[0003] An active antenna typically comprises a set of elementary antennas, each consisting of a substantially planar radiating element coupled to a transmit / receive circuit (T / R circuit). Each transmit / receive circuit is connected to an excitation point. In electronic warfare applications, each transmit / receive circuit includes a power amplification chain that amplifies an excitation signal received from centralized signal generation electronics and excites the excitation point, as well as a low-noise amplification chain that, in receive mode, amplifies a low-level receive signal received by the radiating element at the excitation point and transmits it to a concentrator circuit, which then transmits it to a centralized acquisition circuit.

[0004] This type of array antenna has several drawbacks. Low-noise amplifier chains have different optimal input impedances than power amplifier chains. Typically, the impedance of the excitation points is set to 50 ohms, as instrumentation equipment is designed for this impedance. However, this is not the optimal impedance for high-power amplifiers (HPAs) or low-noise amplifiers (LNAs). To overcome this drawback, it is common practice to use an impedance transformer at the output of the power amplifier chain and at the input of the low-noise amplifier chain.This transformer results in lower transmission efficiency, leading to significant energy losses due to heat dissipation. It also results in a lower noise figure (NF) in reception, as the signal-to-noise ratio of the received signal is degraded.

[0005] It may be necessary to transmit signals of varying power using the same array antenna. For example, one can transmit high-power radar signals with a narrow frequency spread (10 to 20% of the center frequency) and lower-power telecommunication or radar jamming signals with a wide frequency spread (up to three octaves). These signals can be transmitted simultaneously or sequentially.We know, for example, of a planar radiating device in MMIC technology (for "Monolithic Microwave Integrated Circuit" in English or monolithic microwave integrated circuit) comprising a transformer made in the MMIC and allowing to amplify in frequency and power these two types of signals according to the spread bandwidths and the powers required and to sum them before injecting them onto an antenna at the same excitation point.

[0006] However, this solution has drawbacks. This type of transformer with an integrated signal summing junction upstream of the radiating element in the MMIC is bulky and results in significant energy losses. To limit the heating of the integrated circuit, it is essential to cool it, which requires specific equipment and involves substantial energy consumption.

[0007] US 2012 / 188917 A1 describes a wireless device for performing bidirectional wireless transmission, an antenna feed network, and a patch antenna. The wireless device includes an antenna assembly having two inputs that accept two feed signals offset by a phase difference. The antenna assembly receives a radiated signal and produces first and second received signals.

[0008] US 2009 / 289862 A1 relates to an antenna system which includes a transmitting component, a receiving component and an antenna connected to them and arranged to connect to different connection points (6, 7, 8) of the transmitting or receiving element.

[0009] US 2012 / 295556 A1 describes a signal transceiver comprising a first power amplifier coupled to a chip output port of a chip; an impedance transformation circuit; a switching circuit arranged to selectively couple the chip output port to a first port of the impedance transformation circuit; and a receive amplifier coupled to a second port of the impedance transformation circuit.

[0010] EP 2 093 832 A1 describes a power grouping and energy radiation solution.

[0011] US 5 280 297 A describes an active reflector array antenna for reusing communication satellite frequencies.

[0012] US 2010 / 099367 A1 relates to a miniaturized low-power RF transmitter with a dual-mode on-chip active antenna / inductance, the antenna also serving as an oscillator inductance.

[0013] US 2015 / 340759 A1 describes a vehicle comprising a plurality of antennas and a transceiver connected to each of the plurality of antennas and configured to feed selected subsets of the plurality of antennas in order to generate a directional antenna beam.

[0014] One aim of the invention is to propose a planar radiating device that makes it possible to obtain an antenna in which at least one of the aforementioned disadvantages is reduced.

[0015] This object is solved by the object of the independent claims. Preferred embodiments are defined by the dependent claims.

[0016] To this end, the invention relates to an elementary antenna comprising a planar radiating device including a substantially planar radiating element and a transmitting and / or receiving circuit including at least one amplification chain of a first type and at least one amplification chain of a second type, each amplification chain of the first type being coupled to at least one excitation point of a first set of at least one excitation point of the radiating element and each amplification chain of the second type being coupled to at least one point of a second set of excitation points of the radiating element, the excitation points of the first and second sets being distinct and the amplification chain of the first type being different from the amplification chain of the second type so that they exhibit different amplification properties.

[0017] Advantageously, the excitation points of the first set and the second set have distinct impedances.

[0018] According to a first embodiment of the invention, the antenna comprises a transmission and reception circuit, said transmission and reception circuit comprising: at least one transmit amplification chain suitable for delivering signals intended to excite the radiating element, each transmit amplification chain being coupled to at least one point of the first set of at least one excitation point of said radiating element; at least one receive amplification chain suitable for amplifying signals from the radiating element, each receive amplification chain being coupled to at least one point of the second set of at least one excitation point of said radiating element.

[0019] The excitation points are positioned and coupled to the respective amplification chains so that each amplification chain is loaded substantially by its optimal impedance, the impedance loaded on each amplification chain being the impedance of the chain formed by the radiating device coupled to the amplification chain and by each supply line connecting the radiating device to the amplification chain.

[0020] At least one transmit amplification chain coupled to one or two points of the first set has an output impedance that is substantially the conjugate of an impedance of the radiating device presented to said transmit amplification chain, said point or between the two points of the first coupled set(s); and / or at least one receive amplification chain coupled to one or two points of the first set has an output impedance substantially the conjugate of an impedance of the radiating device presented to said receive amplification chain, said point or between the two points of the second coupled set(s).

[0021] According to a second embodiment of the invention, the elementary antenna comprises a transmission circuit, the transmission circuit comprising: at least one high-power emission amplification chain suitable for delivering signals intended to excite the radiating element, each high-power emission amplification chain being coupled to at least one point of the first set of at least one excitation point of said radiating element; at least one second low-power emission amplification chain, of lower power than the first high-power amplification chain, suitable for delivering signals intended to excite the radiating element, each low-power emission amplification chain being coupled to at least one point of the second set of at least one excitation point of said radiating element.

[0022] The excitation points are positioned and coupled to each high-power emission amplification chain so that each high-power amplification chain is loaded substantially by its optimal impedance, the impedance loaded on each high-power amplification chain being the impedance of the chain formed by the radiating device coupled to the amplification chain and by each feed line coupling the radiating device to the high-power emission amplification chain.

[0023] At least one high-power emission amplification chain coupled to one or two points of the first set has an output impedance that is substantially the conjugate of an impedance of the radiating device presented to said emission amplification chain at said point or between the two points of the first set.

[0024] Both embodiments may include one or more of the following features, taken individually or in any technically possible combination: The impedance of each excitation point in the first set is less than the impedance of each excitation point in the second set. The radiating element is defined by a first line passing through a central point of the radiating element and a second line perpendicular to the first line and passing through the central point, the excitation points being distributed only on the first and / or the second line. The radiating device comprises two slots extending longitudinally along the first line and the second line, the two slots ensuring the coupling of all the excitation points; at least one set taken from the first set and the second set comprises at least one pair of excitation points, the pair of excitation points comprising two excitation points coupled to the transmitting and / or receiving circuit so that a differential signal is intended to circulate between the radiating device and the transmitting circuit; at least one set taken from the first set and the second set comprises a first quadruplet of excitation points; the radiating element being defined by a first line passing through a center of the radiating element and a second line perpendicular to the first line and passing through the center.The excitation points of each first quadruplet of excitation points comprise a first pair of excitation points composed of excitation points arranged substantially symmetrically with respect to said first line and a second pair of excitation points composed of excitation points arranged substantially symmetrically with respect to said second line. The excitation points of the first quadruplet of points are located at a distance from the first line and the second line. Each set comprises a first quadruplet of excitation points located on the first line and on the second line. Each set consists of a first quadruplet of points, the excitation points of each first quadruplet of points being located on one side of a third line situated in the plane defined by the radiating element, passing through the central point and being a bisector of the angle formed by the first and second lines.The assembly comprises a second quadruple of excitation points located at a distance from the first line and the second line, comprising: a third pair composed of excitation points arranged substantially symmetrically with respect to said first line, the points of the third pair of points being arranged on the other side of the second line with respect to the first pair of excitation points of said assembly; a fourth pair composed of excitation points arranged substantially symmetrically with respect to said second line, the points of the fourth pair of points being arranged on the other side of the first line with respect to the second pair of excitation points of said assembly; each assembly taken from the first and second assemblies comprises a first and a second quadruple of points; the antenna comprises phase-shifting means for introducing a first phase shift between a first applied signal,or originating from, the first pair of excitation points and a second signal applied to, or respectively originating from, the second pair of excitation points and a second phase shift of said set, which may be different from the first phase shift, between a third signal applied to, or respectively originating from, the third pair or originating from the third pair of excitation points of said set and a fourth signal applied to, or respectively originating from, the fourth pair of excitation points of said set, the first quadruple of points and the second quadruple of points of at least one set being excited by means of signals of distinct frequencies or being summed separately.

[0025] Advantageously, and generally applicable to both embodiments, each amplification chain of the first type is associated with an amplification chain of the second type, these amplification chains being coupled to excitation points arranged to emit or receive respective elementary waves linearly polarized along the same direction. In other words, this direction is common to the amplification chains associated with each other.

[0026] The invention also relates to an antenna comprising several elementary antennas, the radiating elements forming a network of radiating elements.

[0027] Advantageously, the antenna includes pointing phase-shifting means that allow first global phase shifts to be introduced between signals applied to, or originating from, the first quadruplets of points of at least one set of points of the respective elementary antennas and second global phase shifts between signals applied to, or respectively originating from, the second quadruplets of points of said set of points of the respective elementary antennas, the first and second global phase shifts being able to be different.

[0028] Other features and advantages of the invention will become apparent from the following detailed description, given by way of non-limiting example and with reference to the accompanying drawings in which: there figure 1 schematically represents a first example of an elementary antenna according to a first embodiment of the invention, the figure 2 represents a basic antenna in side view, the figures 3 , 4 And 5 schematically represent three variants of the elementary antenna according to the first embodiment of the invention, the figure 6 represents a table listing different polarizations that can be obtained using the system of the figure 5 , THE figures 7 , 8 , 10 And 11 represent four other variants of the elementary antenna according to the invention figure 4 schematically represents an elementary antenna according to a second embodiment of the invention, the figure 9 represents a table listing different polarizations that can be obtained using the antenna of the figure 8 , there figure 12 represents an example of a planar radiating device according to the invention, the figures 13 à 20 represent 7 examples of an elementary antenna according to a second embodiment of the invention, the figure 21 schematically represents the reflection coefficients of the first excitation point of the antenna of the figure 13 .

[0029] From one figure to another, the same elements are identified by the same references.

[0030] On the figure 1 , we have represented an example of an elementary antenna 1A according to the invention comprising a planar radiating device 10 and a processing circuit or transmit / receive module 20a.

[0031] The planar radiating device 10 comprises a substantially planar radiating element 11, extending substantially in the plane of the sheet. The planar radiating device is a planar antenna more commonly known as a patch antenna.

[0032] The invention also relates to an antenna comprising several elementary antennas according to the invention. The antenna may be of the array type. The radiating elements 11 or the planar radiating devices 10 of the elementary antennas form an array of radiating elements. Advantageously, the radiating elements are arranged such that their respective radiating elements 11 are coplanar and have the same orientation with respect to a fixed coordinate system in the plane of the radiating elements. Alternatively, the radiating elements are arranged in another configuration.

[0033] The antenna is advantageously an active antenna.

[0034] The planar radiating device 10 forms a stacking as shown on the figure 2 It comprises a radiating element 11, substantially planar, arranged above a layer forming the ground plane 12. A gap is provided between the radiating element 11 and the ground plane 12. This gap includes, for example, an electrically insulating layer 13 made of a dielectric material. Preferably, the radiating element 11 is a plate made of a conductive material. Alternatively, the radiating element 11 comprises several stacked metal plates. It is conventionally square in shape. Alternatively, the radiating element may have another shape, for example, a disk or another parallelogram shape such as a rectangle or a rhombus. Regardless of the geometry of the radiating element 11, it is possible to define a center C.

[0035] The elementary antenna includes feed lines 51, 52, formed of conductors, i.e. tracks, coupled with the radiating element 11 at excitation points 1 or respectively 2 included in the radiating element 11. This coupling allows the excitation of the radiating element 11.

[0036] The tracks are, for example, frequency-tuned.

[0037] The coupling is achieved, for example, by electromagnetic coupling through a slot. The planar radiating device 10 then includes a feed plane 16 visible on the figure 2 carrying the ends of the feed lines. The plane 16 is advantageously separated from the ground plane 12 by a layer of insulating material 17, for example a dielectric. The planar radiating device 10 also includes at least one slot f formed in the layer forming the ground plane. The ends of the feed lines 51, 52 are arranged so as to overlap the corresponding slot f from below, the radiating element 11 being located above the layer forming the ground plane 12. The excitation points 1 and 2 are then located at the slot f and the end of the corresponding feed line 51, 52. The feed lines are connected to the terminals of the corresponding strings. On the figure 1 The projection of the slit f is represented by dashed lines. Regarding the realization of the figure 1 A slit f is provided for the two excitation points. Alternatively, one slit is provided per excitation point or for a plurality of excitation points, for example, a pair of excitation points intended to be differentially excited, or for several pairs. For clarity, the slits are not shown in all the figures. The slits are not necessarily rectangular; other shapes are possible.

[0038] Alternatively, coupling is achieved by electrically connecting the end of the power line to an excitation point on the radiating element. For example, at the end of the power line, the excitation current flows to the radiating element through the insulating material, for instance, via a metallized via that connects the power line to a pin located on the back of the radiating element at the point to be excited. Coupling can also be performed on the surface of the flat radiating element, or "patch," by directly connecting a printed microstrip line to its edge. The excitation point is then located at the end of the power line. Excitation can also be achieved by proximity coupling to a microstrip line printed at a level between the patch and the layer forming the ground plane.

[0039] Coupling can be achieved in the same way or differently for different excitation points.

[0040] What has been said previously applies to all embodiments of the invention.

[0041] According to the invention, the radiating element 11 comprises a first set of at least one excitation point, consisting of the excitation point 1 on the figure 1 , and a second set of at least one excitation point, consisting of point 2 on the figure 1 The excitation points of the two sets are distinct. In other words, the two sets have no points in common.

[0042] The points in both sets are coupled to signal amplification chains of two distinct types, resulting in different amplification properties. This coupling is simultaneous. In other words, these amplification chains are configured to process different signals. Consequently, they present different optimal impedances to the radiating device, or they have different impedance matching requirements with the radiating device. For example, one might include at least one transmit amplification chain configured to amplify a signal to deliver an excitation signal, which is then applied to the radiating device for one of the point sets, and at least one receive amplification chain configured to receive and amplify a received signal from the other point set.Alternatively, two receiver amplification chains can be provided with distinct power levels and therefore different requirements in terms of impedance matching.

[0043] The invention allows the impedance of the excitation points of the two sets of points to be adjusted independently. By dedicating different excitation points to distinct functions, for example, transmission and reception or transmission of high-power signals and transmission of low-power signals, the impedances seen by the different amplification chains can be adapted independently. Regarding the particular embodiment of the figure 1 The transmit and receive circuit 20a comprises a transmit amplification chain 110a coupled to point 1, which amplifies signals from an unshown microwave signal generation circuit and delivers signals to excite point 1, and a receive amplification chain 120a coupled to point 2, which processes signals from point 2. The two amplification chains exhibit different amplification properties. In other words, these chains contain amplifiers with distinct characteristics.The transmit amplification chain 110a is, for example, a power amplification chain in the field of electronic warfare, comprising a transmit amplifier configured to emit signals, for example, a high-power amplifier (HPA) 114a, and the receive amplification chain comprises a measurement amplifier 116a configured to process signals from a sensor, here the radiating device 10, which is, for example, a low-noise amplifier (LNA). The coupling between each transmit or receive amplification chain and an excitation point 1 or 2 is achieved by means of a power supply line 51 or 52, respectively. This applies to all figures, but the power supply lines associated with the excitation points are not referenced in all figures for clarity.

[0044] Each amplification chain is designed to have optimal performance when loaded (at the output for a transmit amplification chain or at the input for a receive amplification chain) by a well-defined optimal impedance; it has degraded performance when loaded by an impedance different from this optimal value.

[0045] The optimal input or output impedance of an amplification chain is substantially the optimal input impedance of the input amplifier or respectively the optimal output impedance of the output amplifier of the amplification chain.

[0046] Advantageously, the excitation points 1 and 2 are positioned and coupled to the respective amplification chains 110a or 120a so that each amplification chain 110a or 120a is loaded substantially by its optimal impedance. This is called impedance matching.

[0047] Advantageously, the load impedance on an amplification chain 110a or 120a is the impedance of the chain formed by the radiating device 10 coupled to the amplification chain 110a or 120a at the excitation point 1 or 2, and by each feed line 51 or 52 coupling the radiating device 10 to the amplification chain 110a or 120a at the corresponding excitation point. This chain is a source when coupled to a receiving amplification chain and a load when coupled to a transmitting amplification chain.

[0048] Therefore, the proposed solution optimizes power consumption in transmit mode and improves the noise figure in receive mode. Consequently, it is possible to avoid costly performance compromises in impedance matching or the need for an impedance transformer.

[0049] The advantage of such a solution is the optimized impedance matching for each of the two functions, transmission and reception. It should be noted that the transmission signals are significantly stronger than the reception signals, and that the amplifiers in the transmission amplification chains, particularly the power amplification chains, have low optimal output impedances, typically around 20 Ohms, while the amplifiers in the reception amplification chains, particularly the low-noise amplification chains, have a higher optimal output impedance, typically around 100 Ohms, for which they exhibit a better noise figure.

[0050] Therefore, the points are advantageously positioned and coupled to the amplification chains so that the transmitting amplification chain 110a is loaded onto an impedance having a resistive part lower than the impedance loaded onto the receiving amplification chain 120a.

[0051] Impedance matching is advantageously achieved by adjusting the positions of the excitation points.

[0052] Regarding the specific implementation of the figure 1 The distance between each excitation point and the center C is adjusted to match its impedance. The distance between each excitation point 1 and 2 and the center C varies in the same direction as its impedance. Point 1, being closer to the center C than point 2, has a lower impedance than point 2.

[0053] More generally, in all variants of the first embodiment, the excitation points of the first and second sets exhibit distinct impedances. These impedances are measured with respect to ground. In the embodiments shown in the figures, the excitation points of the first set exhibit lower resistive impedances than the impedances of the points of the second set. These impedances are measured with respect to ground.

[0054] When these two sets have distinct impedances, the excitation points that compose it advantageously have identical impedances.

[0055] In an advantageous embodiment, the impedances of the supply lines are negligible so that the impedance loaded on an amplification chain 110a or 120a is substantially that of the radiating device 10 at the excitation point or between the excitation points coupled to the amplification chain.

[0056] According to the invention, in order to achieve optimal impedance matching, the output impedance of the transmission amplification chain 110a coupled to the excitation point, point 1 on the figure 1 , is substantially the conjugate of the impedance of the radiating device 10 presented to said transmission amplification chain 110a at said point 1 and the input impedance of the reception amplification chain 120a coupled at point 2 is substantially the conjugate of the impedance of the radiating device 10 presented to the reception amplification chain 120a at point 2 on the figure 1 The input or output impedance of an amplification chain is substantially the input impedance of the input amplifier or respectively the output impedance of the output amplifier of the amplification chain.

[0057] The proposed solution also isolates the receiving amplifier chain 120a from the transmitted wave. Indeed, the receiving amplifier chain 120 receives only a portion of the signal emitted by point 1 equal to the ratio of the impedance magnitude of point 1 to the impedance magnitude of point 2. If point 1 has an impedance of 20 ohms, corresponding to the optimal output impedance of the transmitting amplifier chain 110a, and point 2 has an impedance of 100 ohms, corresponding to the optimal input impedance of the receiving amplifier chain 120a, there is a 7 dB isolation between the two chains 110a and 120a. It is therefore not necessary to provide a switch to switch between transmit and receive modes nor to provide a circulator to avoid saturating, or even destroying, the 120a receive amplification chain during transmission.We gain in robustness, reliability, and detection accuracy (it should be noted that the switches influence the noise figure at the receiver, must be resistant to the total power, and must be able to switch at the frequency of the transition from transmit to receive mode). We also save weight and cost compared to solutions using circulators. Integrating a circulator into the X-band mesh is very difficult due to its size. The solution also allows for simultaneous transmission and reception. On the... figure 1 The transmit amplification chain 110a comprises a single amplifier 114a, for example, a power amplifier. Alternatively, it may comprise several amplifiers. The receive amplification chain 110a comprises an amplifier, for example, a low-noise amplifier 116a. Alternatively, it may comprise several. The receive amplification chain 120a also includes a protection means such as a limiter 117a, for example, a PIN diode, to protect the receive amplification chain 110a from external interference. These features apply to all embodiments of the invention.In general, according to the first embodiment of the invention, the antenna's transmitting and receiving circuit comprises a transmitting circuit for delivering signals intended to excite the radiating element, coupled to the first set of excitation points, and a receiving circuit for processing received signals from the radiating element, coupled to the second set of points. Advantageously, the transmitting circuit is coupled to the first set of points, and the receiving circuit is coupled to the second set of points. The transmitting and receiving circuits are not coupled at common points. In other words, each transmitting amplification chain is coupled to one or two points of the first set of points, and each receiving amplification chain is coupled to one or two points of the second set. The transmitting and receiving chains are not coupled at common points of the first and second sets.

[0058] For example, the figure 1 Each assembly comprises an excitation point 1 or 2. In an antenna variant 1a shown on the figure 3 , at least one of the radiating device assemblies 10a includes a pair of excitation points configured to be differentially excited. Doubling the excitation points increases the emission power by 3dB compared to the implementation of the figure 1 , when the pair of points is connected to a transmission amplification chain, and the linearity of 3dB in reception with respect to the realization of the figure 1 When the pair of points is connected to a receiver amplification chain, for the same received power, each receiver will only receive half the power. This provides better protection against strong fields.

[0059] Alternatively, the antenna includes at least one pair of excitation points. In the following text, a pair of excitation points refers to two excitation points positioned and coupled to the processing circuit so that the processing circuit is configured to excite the points of the pair with differential, i.e., balanced, signals, or to process differential, or balanced, signals from the pair of points. The points of a given pair are thus, at any given time, excited by opposing signals. The excitation points of a pair of excitation points are coupled to the same amplification chain and are the only excitation points coupled to that amplification chain.

[0060] On the figure 3 The first set of excitation points consists of a first pair of 5+ and 5- excitation points, and the second set of excitation points consists of a first pair of 6+ and 6- excitation points. On the figure 3 , these points are located on the same line D1 of the radiating element 11a of the radiating device 10a passing through the center C of the radiating element 11a. They are arranged in a substantially symmetrical way with respect to the center C so as to present the same impedance.

[0061] The processing circuit 20, or transmit / receive module, comprises a transmit amplification chain 110 and a receive amplification chain 120. Points 5+ and 5- are positioned and coupled to the transmit amplification chain 110 such that the transmit amplification chain excites points 5+ and 5- by means of a differential signal. The transmit amplification chain 110 includes a transmit amplifier 114, for example, a power amplifier. The transmit amplification chain 110 is coupled to points 5+ and 5- via respective power supply lines 51a and 51b. In the non-limiting example of the figure 3 The 110 channel is configured to amplify two opposing or 180° out-of-phase signals received at its input. Alternatively, it could receive an asymmetric signal and deliver differential signals.

[0062] The receiver amplification chain 120 is, for example, a low-noise amplification chain 120 comprising a measurement amplifier 114, for example, a low-noise amplifier. It differs from that of the figure 1 in that it is designed to acquire differential signals. This 120 channel is coupled to points 6+ and 6- in order to acquire differential signals from these points. The 120 channel amplifies and delivers a differential signal. Alternatively, it could deliver an asymmetric signal as on the figure 1 The 120 chain is connected to points 6+ and 6- respectively via power lines 52a and 52b. The 120 receive amplification chain also includes a protection device such as a limiter 117 to protect the 120 receive amplification chain from external interference.

[0063] Advantageously, the excitation points 5+, 5-, +, 6- are positioned and coupled to the respective amplification chains 110 or 120 such that each amplification chain 110 or 120 is loaded substantially by its optimal impedance. Advantageously, the impedance loaded on an amplification chain 110 or 120 is the impedance of the chain formed by the radiating device 10 coupled to the amplification chain 110 or 120 between the excitation points 5+, 5- or 6+, 6- and by the lines 51a and 51b or 52a or 52b coupling the radiating device 10, i.e., points 5+, 5- or 6+, 6-, to the corresponding amplification chain 110 or 120.

[0064] Thus, the points of the two sets exhibit distinct impedances as previously stated.

[0065] Advantageously, but not necessarily, the impedance loaded on each amplification chain 110 or 120 is substantially the impedance of the radiating device 10a measured between the two excitation points 5+ and 5- or 6+ and 6- coupled to the corresponding amplification chain 110 or 120.

[0066] Advantageously, as in the previous figure, the impedance of the radiating device 10 presented to the transmitting amplification chain between points 5+ and 5-, that is to say the differential impedance of the radiating device 10a between these points, is substantially the conjugate of the output impedance of the receiving amplification chain 110 and the impedance of the radiating device 10a presented to the receiving amplification chain between points 6+ and 6- is substantially equal to the input impedance of the receiving amplification chain 120. These impedances are real.

[0067] On the figure 4 We have represented an antenna 1b which is a variant of the figure 3 This variant differs from that of the figure 3 in that one of the sets, here the first set, is composed of a pair of excitation points 5+, 5- excited differentially as on the figure 3 and the other set of points, here the second set is composed of an excitation point which is point 2 excited asymmetrically as on the figure 1 .

[0068] On the figures 1 , 3 And 4 The excitation points of the first and second sets are arranged on the same straight line D1 of the radiating element passing through the center C of the radiating element. This allows all points to be excited by means of a single slit f shown on the figure 1 extending along the line D1, thus facilitating implementation. In the figures, this line D1 is parallel to one side of the radiating element 11. Alternatively, all excitation points are arranged on a line passing through the center of the radiating element 11 and two vertices of the radiating element 11. Alternatively, at least one set of points from the two respective sets is arranged along or near two respective orthogonal sides of the radiating element 11. Alternatively, the points of the two respective sets are arranged on two orthogonal lines passing through the center C, as shown in the figures. figures 11 And 12 which will be described later. The coupling of all points can be achieved by means of only two slits extending along the respective straight lines.

[0069] In a variant shown on the figure 5 Each set comprises two quadruplets of excitation points 1a+, 1a-, 2a+, 2a- and 3a+, 3a-, 4a+, 4a- and respectively 1b+, 1b-, 2b+, 2b- and 3b+, 3b-, 4b+, 4b-. Each quadruplet of points comprises two pairs of excitation points arranged along respective orthogonal lines, the excitation points of each pair of excitation points being arranged so that they can be differentially excited.

[0070] In the specific example of the figure 5 The plane of the radiating element 11c of the planar radiating device 10c is defined by two orthogonal directions. These two directions are the first line D1 and the second line D2. Each of these orthogonal directions passes through the center C. In the non-limiting realization of figures 5 à 10 These lines are parallel to the respective sides of the radiating element, which is rectangular. This rectangle is a square, in the non-limiting example of these figures.

[0071] The first set of excitation points comprises a first quadruple of excitation points which are all located at a distance from the lines D1 and D2, that is to say, which are all offset from these lines D1 and D2, said first quadruple of points comprising: a first pair of excitation points 1a+, 1a- composed of an excitation point 1a+ and an excitation point 1a- arranged substantially symmetrically with respect to the first line D1, a second pair of excitation points 2a+, 2a- composed of an excitation point 2a+ and an excitation point 2a- arranged substantially symmetrically with respect to the second line D2.

[0072] The first set of excitation points includes a second set of four excitation points, all located at a distance from lines D1 and D2, the second set of points comprising: a third pair of excitation points 3a+, 3a- consisting of one excitation point 3a+ and one excitation point 3a- arranged substantially symmetrically with respect to the first line D1, the excitation points 3a+ and 3a- of the third pair of points being arranged on the other side of the second line D2 with respect to the first pair of excitation points 1a+, 1a- , a fourth pair of excitation points 4a+, 4a- comprising one excitation point 4a+ and one excitation point 4a- arranged substantially symmetrically with respect to the second line D2, the excitation points 4a+ and 4a- of the fourth pair of points being arranged on the other side of the first line D1 with respect to the second pair of excitation points 2a+, 2a-.

[0073] The points of each pair are substantially symmetrical to each other by orthogonal symmetry with axis D1 or D2.

[0074] The excitation points of each of the two sets of four points are distinct. In other words, the two sets of four points do not share any excitation points. The different pairs do not share any excitation points.

[0075] The second set comprises a first quadruple of points consisting of a first pair 1b+, 1b- and a second pair 2b+, 2b- exhibiting the same characteristics as the first quadruple of points 1a+, 1a-, 2a+, 2a- of the first set listed above, but with different impedances. The second set also includes a second quadruple of points consisting of a third pair 3b+, 3b- and a fourth pair 4b+, 4b- exhibiting the same characteristics as the second quadruple of points 3a+, 3a-, 4a+, 4a- of the first set listed above, but with different impedances.

[0076] Advantageously, the points of a pair of excitation points are arranged to have identical impedances measured with respect to ground so that they can be differentially excited. Advantageously, all points of the same set have the same impedance. To this end, on the realization of the figure 5 In which the radiating element 11 is a square and the lines D1 and D2 are parallel to the respective sides of the squares, the points of the same set of points are located approximately at the same distance from the center C, and the same distance separates the points of each pair of this set. The first and third pairs of each set are then symmetrical to each other with respect to the line D2, and the second and fourth pairs of each set are symmetrical to each other with respect to the line D1.

[0077] The points in the first set exhibit lower impedances than those in the second set. For example, consider the figure 5 , the points of each pair of points are separated by the same distance, and the points of the first set are closer to the center than those of the second set.

[0078] The transmit / receive module 20c of the antenna 1c includes a transmit circuit A comprising four transmit amplification chains 21 to 24 identical to chain 10 of the figure 3 Each transmit amplification chain 21, 22, 23, or 24 is coupled to a pair of excitation points 1a+ and 1a-, 2a+ and 2a-, 3a+ and 3a-, or respectively 4a+ and 4a- from the first set of excitation points and is designed to apply a differential excitation signal to the pair of excitation points. The transmit / receive module 20c includes a receive circuit B comprising four receive amplification chains 31 to 34 identical to the low-noise amplification chain 120 of the figure 3 . Each receiving amplification chain 31 to 34 is coupled to one of the pairs of excitation points 1b+ and 1b-, 2b+ and 2b-, 3b+ and 3b- or respectively 4b+ and 4b- of the second set of excitation points and is suitable for acquiring and processing differential receiving signals from this pair.

[0079] The pair of points 1a+ and 1a- coupled to chain 21 is intended to emit an elementary wave linearly polarized along the direction of D2, as is the pair of points 3a+, 3a- coupled to chain 23, while the pairs 2a+, 2a- and 4a+, 4a- coupled respectively to chains 22 and 24 are intended to emit respective elementary waves linearly polarized along the direction of the line D1.

[0080] The pair of points 1b+ and 1b- coupled to chain 31 is intended to detect an elementary wave linearly polarized along the direction of D2, as is the pair of points 3b+, 3b- coupled to chain 33, while the pairs 2b+, 2b- and 4b+, 4b- coupled respectively to chains 32 and 34 are intended to detect elementary waves linearly polarized along the direction of the line D1.

[0081] Advantageously, the excitation points are positioned and coupled to the respective amplification chains 21 to 24 and 31 to 34 such that each amplification chain 21 to 24 and 31 to 34 is loaded substantially by its optimal impedance. Advantageously, the impedance loaded on an amplification chain 21, 22, 23, 24, 31, 32, 33, 34 is the impedance of the chain formed by the radiating device 10 coupled to the amplification chain, between the two excitation points 1a+ and 1a- or 2a+ and 2a- ..., 4b+ and 4b-, and by the supply lines connecting the radiating device 10c to the corresponding amplification chain.

[0082] Advantageously, but not necessarily, the impedance loaded on each amplification chain, for example 21, is substantially the impedance of the radiating device 10c measured between the two excitation points 1a+ and 1a-, coupled to the amplification chain 21 and the corresponding amplification chain 21.

[0083] Advantageously, the impedance of the radiating device 10 presented to each transmission amplification chain 21, 22, 23 and respectively 24 between the respective pairs of points of the first set 1a+ and 1a-, 2a+ and 2a-, 3a+ and 3a- and respectively 4a+ and 4a- has a resistive part lower than the impedance of the radiating device 10 presented to each reception amplification chain 31, 32, 33 and 34 between each pair of points 1b+ and 1b-, 2b+ and 2b-, 3b+ and 3b- and respectively 4b+ and 4b-.

[0084] Advantageously, but not necessarily, the impedance of the radiating device 10 presented to each transmitting amplification chain 21, 22, 23, and 24, respectively, between the respective point pairs of the first set 1a+ and 1a-, 2a+ and 2a-, 3a+ and 3a-, and 4a+ and 4a-, respectively, is substantially the conjugate of the output impedance of the corresponding transmitting amplification chain 21, 22, 23, and the impedance of the radiating device 10 presented to each receiving amplification chain 31, 32, 33, and 34 between each point pair 1b+ and 1b-, 2b+ and 2b-, 3b+ and 3b-, and 4b+ and 4b-, respectively, is substantially the conjugate of the input impedance of the receiving amplification chain 31, 32, 33, and 34, respectively. 34, correspondent.

[0085] For the sake of clarity, we have not represented, on the figure 5 The complete connections between the respective amplification chains and the planar radiation device are shown. Conversely, the excitation point to which each input of each transmitting amplification chain 21 to 24 and each output of each receiving amplification chain 31 to 34 is coupled has been indicated.

[0086] In transmission, an excitation signal SE applied by the microwave signal generation electronics at the input of the transmit / receive module 20c is divided into four differential excitation signals applied at the input of the respective power amplification chains 21 to 24. The four differential excitation signals are identical except for their respective phases and possibly amplitudes.

[0087] The transmission circuit A includes a splitter 122 allowing the common excitation signal SE to be divided into two excitation signals, which can be asymmetrical as on the figure 1 or symmetrical (i.e., differential or balanced), respectively injected into the input of respective emission phase shifters 25, 26. Each phase shifter 25, 26 delivers a differential signal (as on the figure 5 ) or an asymmetric signal. The output signal from the first transmission phase shifter 25 is split and injected into the input of channels 21 and 23. The output signal from the second transmission phase shifter 26 is split and injected into the input of channels 22 and 24.

[0088] The respective amplification chains 21 to 24 are advantageously coupled to the respective excitation points such that the elementary waves generated by the pair 1a+, 1a- and the pair 3a+, 3a- are polarized in the same direction, and so that the elementary waves excited by the pair 2a+, 2a- and the pair 4a+, 4a- are polarized in the same direction. Thus, the electric fields of the excitation signals applied to the pairs 1a+, 1a- and 3a+, 3a- have the same direction. Therefore, the two pairs of points 1a+, 1a- and 3a+, 3a- allow the same signal to be delivered as from two asymmetrically excited points. The power to be delivered by each amplification chain 21 and 23 is halved, and the current to be delivered by this amplification chain 11 is then divided by the square root of two. Ohmic losses are lower and power amplifiers are easier to make (less powerful).Similarly, the electric fields of the excitation signals applied to the pairs 2a+, 2a- and 4a+, 4a- have the same direction.

[0089] The transmission circuit A includes transmission phase-shifting means 25, 26, comprising at least one phase shifter, allowing the introduction of a first phase shift, called the first transmission phase shift, between the signal applied to the first pair 1a+, 1a- and the signal applied to the second pair 2a+, 2a-, and the introduction of this same first transmission phase shift between the signal applied to the pair 3a+, 3a- and the signal applied to the pair 4a+, 4a-. The elementary excitation signals injected at the input of chains 21 and 23 are in phase. The elementary excitation signals injected at the input of chains 21 and 24 are in phase.

[0090] Advantageously, the first phase shift in transmission is adjustable. The network antenna advantageously includes an adjustment device 35 for adjusting the first phase shift in transmission so as to introduce a predetermined first phase shift in transmission.

[0091] Each pair of excitation points generates an elementary wave. With the first phase shift in emission, the elementary waves emitted by pairs 1a+, 1a- and 3a+, 3a- are out of phase with the elementary waves emitted by pairs 2a+, 2a- and 4a+, 4a-. By recombination in air of the elementary waves, a total wave is obtained whose polarization can be varied by varying the first phase shift in emission. Examples of relative phases between the emission signals injected onto the conductors coupled to the respective coupling points are given in the table of figure 6 as well as the resulting polarizations. Vertical polarization is the polarization along the z-axis shown on the figure 5 Two points excited in opposite phases, separated by 180°, have opposite instantaneous excitation voltages. As an example, the first line of the table of the figure 6 This illustrates the case where the conductors connected to points 1a+, 2a+, 3a+, and 4a+ are held to the same voltage, and the conductors connected to points 1a-, 2a-, 3a-, and 4a- are held to the same voltage, opposite to the previous one. The voltage differential is then symmetrical with respect to the line D3. The bias is therefore oriented along this vertically oriented line. Linear bias at +45° is obtained by exciting only the pairs 1a+, 1a- and 3a+, 3a- with differential excitation signals in phase, without exciting the pairs 2a+, 2a- and 4a+, 4a-. This is achieved, for example, by adjusting the gain of the amplifiers 114 so that they deliver zero power. For this purpose, the amplifiers have a variable gain and gain adjustment means (not shown). In the example of the fifth line, the phase shifts between the points remain the same over time.The evolution of the phases over time produces a right-handed circular polarization.

[0092] In the receiver, receive signals received by the respective excitation point pairs 1b+ and 1b-, 2b+ and 2b-, 3b+ and 3b-, 4b+ and 4b- are applied to the inputs of the respective transmit amplification chains 31, 32, 33, and 34. Each receive amplification chain delivers a differential signal. Alternatively, the receive amplification chain includes a combiner to deliver an asymmetric signal.

[0093] The elementary receive signals from channels 31 and 33 are injected into the input of a first receive phase shifter 29, and those from channels 32 and 34 are injected into the input of a second receive phase shifter 30. These phase shifters 29 and 30 introduce a first phase shift in reception between the receive signals delivered by channels 31 and 33 and those delivered by channels 32 and 34. The receive signals from the receive phase shifters 29 and 30 are summed by means of a summing 220 of module 20, before the resulting receive signal SS is transmitted to the remote acquisition electronics.

[0094] Thus, the receiving circuit B includes receiving phase-shifting means 29, 30 that allow for the introduction of a first receiving phase shift between received signals from pairs 1b+, 1b- and 2b+, 2b- and between received signals from pairs 3b+, 3b- and 4b+, 4b-. Regarding the non-limiting implementation of the figure 1 , these means are located at the exit of chains 31 to 34.

[0095] Advantageously, the initial phase shift at reception is adjustable. The device advantageously includes an adjustment device for adjusting the phase shift at reception, which is device 35, in the non-limiting realization of the figure 5 .

[0096] The relative phases introduced by the transmitting phase-shifting means 25, 26 can be the same as those introduced by the receiving phase-shifting means 29, 30. This makes it possible to receive elementary waves with the same phases as the transmitted elementary waves and thus to perform measurements on a total received wave with the same polarization as the total wave emitted by the elementary antenna. Alternatively, these phases can be different.

[0097] Advantageously, these phases can be independently adjusted. This allows for the transmission and reception of signals with different polarizations.

[0098] Alternatively, the number of phase shifters is different and / or the phase shifters are arranged elsewhere, either at the input of the power amplification chains or at the output of the low noise amplification chains.

[0099] Advantageously, the antenna includes so-called pointing phase-shifting means allowing adjustable global phase shifts to be introduced between the excitation signals applied to the points of the respective elementary antennas of the antenna and / or between reception signals from the points of the respective elementary antennas of the antenna.

[0100] In the non-limiting example of the figure 5 These means include a control device 36 that generates a control signal for the adjustment means 35. The control device 36 generates a control signal SC comprising specific phase-shift signals that control the introduction of initial phase shifts in transmission and reception on the signals received at the input of each transmission and reception phase shifter, and global signals that control the introduction of global phase shifts on the signals received at the input of each transmission and reception phase shifter. The control device 36 transmits these control signals to the adjustment device 35 so that it controls the phase shifters to introduce these phase shifts on the signals they receive. The global phase shifts allow, by recombination of the total waves emitted by the elementary antennas of the array, the selection of the pointing direction of the wave emitted by the antenna and the wave received by the antenna.The electronic scanning of an array antenna is based on the phase shifts applied to the elementary antennas constituting the array, the scanning being determined by a phase law.

[0101] The antenna according to the invention has many advantages.

[0102] Each transmit amplification chain 21 to 24 is designed, in transmission mode, to apply a differential signal, and each transmit amplification chain 31 to 34 is designed, in reception mode, to acquire a differential signal. Since each chain already operates on differential signals, it is unnecessary to interpose a component, such as a balun (for "balanced unbalanced transformer"), to convert a differential signal to an asymmetrical signal. Such an intermediate component degrades power efficiency. Therefore, the power efficiency of the device is improved.

[0103] To operate with high powers, the invention uses transmit amplification chains 21 to 24 coupled to four quadrature polarization accesses two by two and four receive amplification chains 31 to 34 coupled to four quadrature polarization accesses two by two, each chain operating at a rated power compatible with the maximum power acceptable by the technology implemented to manufacture it.

[0104] The power of the electromagnetic waves emitted or received by the radiating element can therefore exceed the nominal operating power of the chain coupled to this pair of excitation points. Each pair of differentially excited excitation points of the radiating element generates an elementary wave. The antenna operates in double differential mode for both transmission and reception. The power of the elementary wave emitted by each pair of points is twice the nominal transmission power of the transmission amplification chain 21 to 24.

[0105] This is particularly advantageous when the nominal power is close to the maximum power allowed by the technology implemented for the realization of the transmission amplification chains 21 to 24. Although at the level of each excitation circuit, the power remains below the maximum power, the elementary antenna allows waves to be emitted at a higher power.

[0106] The choice of technology for the fixed planar radiating device determines the voltage applied to the excitation points. The higher the voltage, the lower the current for equal power and impedance, and the lower the ohmic losses. For the same impedance, halving the output power results in dividing the current by the square root of two. Since the proposed solution adds the power directly to the patch or radiating element 11c, ohmic losses are significantly reduced.

[0107] As previously mentioned, energy summation is performed directly at the excitation points. Therefore, to emit four times more power, it is not necessary to use transmission amplification chains with amplifiers four times more powerful. Nor is it necessary to sum signals from amplifiers of limited power outside the radiating medium, for example, using ring or Wilkinson summers. The invention makes it possible to limit the number of conductors used, as well as the ohmic losses in the conductors, and consequently the power generated to compensate for these losses. Furthermore, to limit losses, it is not necessary to perform energy summation within the MMICs. If summation is performed within the MMICs, the losses must be dissipated in this already critical area. Antenna heating and ohmic losses are thus reduced.

[0108] Furthermore, by differentially exciting the excitation points of each pair, each pair of points emits an elementary wave with linear polarization. By applying a phase shift between the excitation signal of the first pair of points 1a+, 1a- and the third pair of points 3a-, 3a+ and the excitation signals of the second pair of points 2a+, 2a- and the fourth pair of points 4a+, 4a- orthogonal to the first and third pairs of points 1a+, 1a- and 3a-, 3a+, the radiating element 11c is capable of generating, on its own, a wave polarized by recombination in the space of the four elementary waves.

[0109] This eliminates the need for polarization selection switches between the 20c transmit / receive module and the radiating element to choose the direction in which the radiating element should be excited. It also allows the 20c module to be connected directly to the excitation points, thereby increasing power efficiency and reducing losses. This also reduces the heating of the element antenna.

[0110] Furthermore, the recombination in space of the four elementary waves emitted by the radiating element leads to a total wave whose power is four times greater than the power of each elementary wave.

[0111] In reception, the total incident wave is decomposed into four elementary waves transmitted to the respective low-noise amplification chains 31 to 34 and reconstructed by summation. An elementary wave has a power four times lower than the total incident wave. This allows the antenna to be more robust against external interference, such as illumination of the antenna by a device causing intentional or unintentional jamming. The risks of damage to the low-noise amplifiers 116 are limited. For example, interference from strong fields will be reduced because the elementary signals are not received in optimal polarization but at 45° (when the transmissions are either horizontally or vertically polarized but not obliquely). The antenna of the figure 5 allows measurements to be made in cross polarization, a transmission in Horizontal polarization and a reception in Vertical polarization for example by not applying the same first phase shifts in transmission and reception.

[0112] All the advantages can be obtained through the judicious arrangement of the excitation points on the radiating plane.

[0113] On the figure 7 , another variant of the elementary 1d antenna according to the first embodiment of the invention has been represented.

[0114] The planar radiating device 10c is identical to that of the figure 5 The antenna includes an Ad transmission circuit comprising the same transmission amplification chains 21 to 24 as on the figure 5 and a Bd receiving circuit comprising the same receiving amplification chains 31 to 34. These chains are coupled in the same way as on the figure 5 to the respective pairs of excitation points.

[0115] In contrast, the 20d transmit / receive module differs from that of the figure 5 by means of phase shifting. It includes means for phase shifting in transmission comprising at least one phase shifter enabling the introduction of a first phase shift in transmission between the excitation signals applied to the pairs of excitation points 1a+, 1a- and 2a+, 2a- and a second phase shift in transmission between the excitation signals applied to the pairs of points 3a+, 3a- and 4a+, 4a-, these two phase shifts in transmission being able to be different. This makes it possible to transmit waves with different polarizations using the two quadruplets of points.

[0116] In the non-limiting example shown on the figure 7 These phase-shifting means for transmission include a first transmission phase shifter 125a and a second transmission phase shifter 125b receiving the same signal, possibly with a slight amplitude difference, and each introducing a phase shift on the received signal so as to introduce the first phase shift in transmission between the excitation signals applied to the pair 1a+, 1a- and the pair 2a+, 2a-. The phase-shifting means include a third 126a and a fourth 126b transmission phase shifters receiving the same signal, possibly with a slight amplitude difference, and each applying a phase shift to the signal so as to introduce the second phase shift between the excitation signals applied to the pair 3a+, 3a- and the pair 4a+, 4a-. The first and second phase shifts in transmission may be different. The excitation signals from phase shifters 125a and 125b are injected respectively into the input of chains 21 and 22.The excitation signals from the phase shifters 126a and 126b are injected respectively into the input of the chains 23 and 24. It is thus possible to simultaneously emit two beams with different polarizations by means of the two quadruplets of points.

[0117] The receiver circuit Bd includes receive phase-shifting means 129a, 129b, 130a, 130b, which introduce a first phase shift between the excitation signals applied to the excitation point pairs 1b+, 1b- and 2b+, 2b-, and a second phase shift between the excitation signals applied to the point pairs 3b+, 3b- and 4b+, 4b-. These two phase shifts may be different. The receive signals from the respective receive amplification chains 31 to 34 are injected into respective receive phase shifters 129a, 129b, 130a, 130b, each of which introduces a phase shift onto the signal it receives. Each receive signal is injected into one of the phase shifters.

[0118] Advantageously, the phase shifts introduced between the excitation and / or reception signals of the point pairs 1a+, 1a- and 2a+, 2a- and / or 1b+, 1b- and 2b+, 2b- and between the pairs 3a+, 3a- and 4a+, 4a- and 3b+, 3b- and 4b+, 4b- are identical. Alternatively, these phase shifts can be different. This allows the transmission and / or reception of two waves with different polarizations.

[0119] Advantageously, the phase shifts are adjustable.

[0120] Advantageously, the phase shifts introduced between the transmission and / or reception signals applied to the pairs of points 1a+, 1a- and 2a+, 2a- and / or from the pairs 1b+, 1b- and 2b+, 2b- and between the signals applied to the pairs 3a+, 3a- and 4a+, 4a- and / or from the pairs 3b+, 3b- and 4b+, 4b- can advantageously be adjusted independently. We can then independently adjust the polarizations of the elementary waves emitted by the first quadruplet of points 1a+, 1a-, 2a+, 2a- and by the second quadruplet of points 3a+, 3a-, 4a+, 4a- of the first set or measured by the first quadruplet of points 1b+, 1b-, 2b+, 2b- and by the second quadruplet of points 3b+, 3b-, 4b+, 4b- of the second set.

[0121] The network antenna advantageously includes a 35 adjustment device allowing adjustment of the phase shifts in transmission and reception.

[0122] Advantageously, the antenna includes so-called pointing phase-shifting means for introducing initial global phase shifts in transmission between the excitation signals applied to the first quadruplets of points 1a+, 1a-, 2a+, 2a- of the first sets of the respective elementary antennas, and second global phase shifts in transmission between the excitation signals applied to the second quadruplets of points 3a+, 3a-, 4a+, 4a- of the first sets of the respective elementary antennas of the array. The first and second global phase shifts in transmission may be different. Additionally, the antenna includes initial global phase shifts in reception between the received signals from the first quadruplets of points 1b+, 1b-, 2b+, 2b- of the second sets of the respective elementary antennas, and second global phase shifts in reception between the received signals from the second quadruplets of points. 3b+, 3b-, 4b+,4b- of the second sets of respective elementary antennas of the network, the first and second overall phase shifts in reception may be different. It is then possible to simultaneously transmit two beams in two different directions and to receive two beams in two different directions.

[0123] Advantageously, the overall phase shifts in emission of the two sets of points are adjustable.

[0124] Advantageously, the overall phase shifts in transmission and / or reception are independently adjustable. The pointing directions are independently adjustable.

[0125] In the non-limiting example of the figure 7 The pointing phase shifting means include the control device 36 generating a control signal SC comprising various signals commanding the introduction of the aforementioned phase shifts (global and non-global) to be applied to the signals received at the input of the various phase shifters and transmits these signals to the adjustment device 35 so that it commands the phase shifters to introduce these phase shifts on the signals they receive.

[0126] The device of the figure 7 It also offers the possibility of measuring a beam in one direction and emitting a beam in another direction simultaneously, or of taking two measurements in two directions simultaneously. It is possible to transmit and receive a signal in one direction and to transmit and receive communication in another direction. Therefore, cross-transmission / reception is possible. It is possible to form a radiation pattern in receive or transmit mode covering sidelobes and diffuse lobes to enable sidelobe blocking (SBB) functions, which protect the radar from intentional or unintentional jamming signals. It is possible to transmit at different frequencies, which complicates the task of radar detectors (ESM: "Electronic Support Measures").

[0127] On the realization of the figure 7 The chains coupled to the two quadruplets 1a+, 1a-, 2a+, 2a- and 3a+, 3a-, 4a+, 4a- are fed by means of two different power sources SO1, SO2. This allows the transmission of two waves with different frequencies, one by means of the first quadruplet of points 1a+, 1a-, 2a+, 2a- and the other by means of the second quadruplet of points 3a+, 3a-, 4a+, 4a-, when the sources deliver excitation signals E1 and E2 of different frequencies. The antenna of the figure 7 It can thus simultaneously emit two beams directed along two independently adjustable pointing directions at different frequencies. This ability to point two beams in two directions simultaneously provides a dual-beam equivalent: a fast-scanning beam and a slow-scanning beam. For example, a slow beam at 10 revolutions per minute can be used in surveillance mode, and a fast beam at 1 revolution per second can be used in tracking mode. This scanning mode is not interlaced as in single-beam antennas, but can be simultaneous. The ability to transmit at different frequencies complicates the task of radar detectors (ESM: Electronic Support Measures). It also allows for a data link in one direction and a radar function in another. This embodiment also allows for the emission of two beams with different shapes.A narrow beam or a wide beam can be emitted depending on the number of elementary antennas in the array that are excited.

[0128] The transmit / receive module 20d includes a first splitter 211a which divides the excitation signal E1 from the first source SO1 into two identical signals injected into the inputs of the transmit phase shifters 125a and 125b. The circuit 120 includes a second splitter 211b which divides the excitation signal E2 from the second source SO2 into two identical signals injected into the inputs of the transmit phase shifters 126a and 126b.

[0129] For example, but not limited to, the figure 7 The two signals from the first receiving phase shifter 129a, which receives input signals from the first pair of excitation points 1b+, 1b-, and from the second receiving phase shifter 129b, which receives input signals from the second pair of excitation points 2b+, 2b-, are summed by a first summing junction 230a to generate a first output signal SS1. The two signals from the third receiving phase shifter 130a, which receives input signals from the third pair 3b+, 3b-, and from the fourth receiving phase shifter 130b, which receives input signals from the fourth pair of excitation points 4b+, 4b-, are summed by a second summing junction 230b to generate a second output signal SS2. The signals from the respective summing junctions are transmitted separately to the remote acquisition electronics.This allows differentiation between received signals with different frequencies. The signals from the two quadruplets of points 1b+, 1b-, 2b+, 2b- and 3b+, 3b-, 4b+, 4b- of the second set being summed separately, it is possible to form a receiving antenna covering the sidelobes and the scatters to allow sidelobe opposition (SAO) functions to protect the radar from intentional or unintentional jamming signals.

[0130] Alternatively, the two excitation signals E1 and E2 have the same frequency. A more powerful total wave can therefore be obtained, as in the embodiment of the figure 5 or emit two signals of the same frequency in two different directions and / or with different polarizations.

[0131] On the figure 8 We have represented an elementary 1d antenna which is another variant of the first embodiment of the invention.

[0132] The elementary 1d antenna of the figure 8 differs from that of the figure 5 in that the radiating element 11e of the radiating device 10e comprises a first set of points consisting only of the first quadruple of points 1a+, 1a-, 2a+ and 2a- and in that it comprises a second set of points consisting only of the first quadruple of points 1b+, 1b- and 2b+ and 2b-. The associated transmitting / receiving device 20e differs from that of the figure 5 in that it comprises only the part of the transmitting / receiving device coupled to these excitation points. On the figure 8 , as on the figures 10 And 11For clarity, the adjustment device 35 and the control device 36 have not been shown. Exciting the radiating element with two excitation signals applied to pairs of excitation points located in quadrature with each other allows the transmission / reception pattern of the elementary antenna to be symmetrical. This elementary antenna is capable of transmitting a wave with adjustable polarization and receiving a wave with an adjustable polarization direction. Examples of the phases of the signals injected onto the conductors coupled to the respective coupling points are given in the table. figure 9 as well as the resulting polarizations. Consider the first line as an example. Points 1a+ and 2a+ have the same excitation (same phases), and points 1a- and 2a- have the same excitation, opposite to that of the other points. The polarization is therefore vertical, that is, along the z-axis shown on the graph. figure 8 .

[0133] This basic antenna also allows the construction of array antennas capable of emitting a total wave with an adjustable pointing direction, but with half the power of the... figure 5 .

[0134] Advantageously, the excitation points 1a+, 1a-, 2a+, 2a-, 1b+, 1b- and 2b+ and 2b- of the elementary antenna of the figure 8 are located on the same side of a third line D3 situated in the plane defined by the radiating element, passing through the central point C and bisecting the angle formed between lines D1 and D2. When the radiating element is a square and lines D1 and D2 are parallel to the respective sides of the square, the third line joins the two vertices of the square. This allows one half of the radiating element to be freed up, for example, to perform other types of excitation.

[0135] Advantageously, each first quadruple of points 1a-, 1a+ and 2a+, 2a- and 1b-, 1b+ and 2b+, 2b- of the figures 5 And 7 are also located on the same side of the right D3.

[0136] On the figure 10 We have represented an elementary antenna 1f which is another variant of the first embodiment of the invention. The elementary antenna of the figure 10 differs from that of the figure 8 by the arrangement of the quadruplets of points from the two sets. More precisely, the elementary antenna of the figure 10 differs from that of the figure 8 in that the excitation points of the first set 1a-, 1a+ and 2a+, 2a- are located on the opposite side of the third line D3 from the excitation points of the second set 1b-, 1b+ and 2b+, 2b-. Consequently, the excitation points 1a+ and 1a- are located on the opposite side of the line D2 from the points 1b+ and 1b-, and the points 2a+ and 2a- are located on the opposite side of the line D1 from the points 2b+ and 2b-. This embodiment is easier to implement than that of the figure 8 because the excitation points of the two sets are further apart from each other.

[0137] On the figure 11 We have represented an elementary 1g antenna which is another variant of the first embodiment. This elementary antenna differs from that of the figure 8 by the arrangement of the quadruplets of points from the two sets on the radiating element 11g of the planar radiating device 10g. The arrangement of points 1a+, 1a- and 1b+, 1b- differs from that of the figure 8 in that these points are arranged on the second line D2 and the arrangement of points 2a+, 2a- and 2b+, 2b- differs from that of the figure 8 in that they are arranged on the first line D1. The lines D1 and D2 are parallel to the respective sides of the rectangular plane element, which can be square as on the figure 8 .

[0138] On the figure 12 We have represented a 10g radiating device with an 11g radiating element. The elementary antenna formed from this device advantageously has the same transmit / receive module as on the figure 11 This basic antenna differs from that of the figure 11 by the arrangement of the lines D1 and D2 along which the two sets of four points extend. In this variant, the orthogonal lines D1 and D2 connect opposite vertices of the square.

[0139] The variants of figures 11 And 12 are advantageous because they allow coupling of the eight excitation points using only two slots, f1 and f2 or f3 and f4, extending longitudinally along the two lines D1 and D2. These antennas offer the same advantages as the antenna of the figure 8 in terms of gains and polarizations.

[0140] In one variant, the second set of points is identical to that of the figures 5 And 7 : 1a+, 1a-, 2a+, 2a-, 3a+, 3a-, 4a+, 4e. The transmitting / receiving circuit advantageously includes the portion of circuit 20c of the figure 5 or the 20d circuit of the figure 7 which is coupled to these points. The first set of points is identical to that of the figure 8 : 1b+, 1b-, 2b+, 2r. The transmitting / receiving circuit advantageously includes part of the 20th circuit of the figure 10 which is coupled to these points. This embodiment makes it possible to transmit at a high power and to limit the number of excitation points and therefore conductors used for detection when the measured power is low.

[0141] Thus, in the first embodiment, each point in the first set of points is coupled to a transmit amplification chain 110a and each point in the second set is coupled to a receive amplification chain 120a. The points in the first set are not coupled to the receive amplification chains and the points in the second set are not coupled to the transmit amplification chains.

[0142] Advantageously, the excitation points are positioned and coupled to the respective amplification chains so that each amplification chain is loaded substantially by its optimal impedance. The impedance loaded on an amplification chain is advantageously the impedance of the chain formed by the radiating device, coupled to the amplification chain at the excitation point(s), and by each feed line connecting the radiating device to the amplification chain.

[0143] In an advantageous embodiment, the impedances of the supply lines are negligible so that the impedance loaded on an amplification chain is substantially the load formed by the radiating device at the excitation point or between the excitation points coupled to the amplification chain.

[0144] According to the invention, to optimize efficiency, the output impedance of each transmitting amplification chain coupled to one or two excitation points is substantially the conjugate of the impedance of the radiating device 10 presented to said transmitting amplification chain 110a at said point or between said points and the input impedance of each receiving amplification chain 120a coupled to one or two excitation points is substantially the conjugate of the impedance of the radiating device presented to the receiving amplification chain 120a at or between said points.

[0145] On the figure 13 A first example 1000 of a second embodiment of the antenna according to the invention is shown. This antenna comprises a planar radiating device 10 identical to that of the figure 1 In this second embodiment, the processing module includes a 200a transmission circuit comprising a high-power transmission circuit designed to deliver signals to excite the radiating element. This circuit includes a high-power 110a transmission amplification chain on the figure 1 3 to excite the radiating element and a low-power transmission circuit. The transmission circuit 200a includes another transmission circuit, a so-called low-power transmission circuit, which has a lower power rating than the receiving circuit. This transmission circuit includes a so-called low-power transmission amplification chain 220a. The high-power transmission amplification chain 110a is coupled to the first point 1, and the low-power transmission amplification chain 220a is coupled to the second point 2.

[0146] Generally applicable to all variants of the second embodiment, the processing circuit comprises a high-power transmission circuit designed to deliver high-power signals intended to excite the radiating element, and a low-power transmission circuit designed to deliver lower-power signals intended to excite the radiating element. The high-power transmission circuit is coupled to a first set of at least one excitation point of the transmission circuit, and the low-power transmission circuit is coupled to a second set of at least one excitation point. These circuits are not coupled to the same points of the first and second sets.The high-power transmission circuit includes at least one high-power amplification chain, and the low-power transmission circuit includes at least one low-power amplification chain with a lower power rating than the high-power amplification chain. A high-power amplification chain is defined as a transmission amplification chain capable of delivering a higher maximum power signal than a low-power amplification chain. Each high-power amplification chain is coupled to one or two points of the first set of points, and each low-power amplification chain is coupled to one or two points of the second set. The high- and low-power transmission chains are not coupled to common points of the first and second sets.The power ratio between the maximum emission powers of the two types of emission amplification chains can typically be up to 10 dB.

[0147] The advantage of such a solution is to allow independent impedance matching for both types of signals (high and low power) while ensuring summation of these signals directly on the radiating element (on distinct excitation points) which limits energy losses.

[0148] It is possible to predict that each high-power 110a transmission amplification chain coupled to an excitation point is such that it is capable of exciting it asymmetrically (as on the figure 13 ) or coupled to a pair of excitation points (as in the following figures) so as to differentially excite it, is loaded onto a circuit substantially by its optimal impedance. This impedance loaded onto a high-power amplification chain is the impedance of the chain formed by the radiating device coupled to the high-power amplification chain at the excitation point(s) and by each feed line connecting the radiating device to the amplification chain at the corresponding excitation point(s). This impedance matching avoids the need for a specific impedance transformation component between the output of the high-power amplification chain and its excitation point without the impedance of the low-power signals being detrimental.

[0149] In an advantageous embodiment, the impedances of the supply lines are negligible so that the impedance loaded on a high-power amplification chain is substantially the impedance of the radiating device at the excitation point or between the excitation points coupled to this amplification chain.

[0150] Advantageously, in order to achieve optimal impedance matching, the output impedance of each high-power transmission amplification chain 110a is substantially the conjugate of the impedance presented by the radiating device 10 to the high-power transmission amplification chain at said point or between said points, which makes it possible to obtain a high transmission efficiency which is crucial for high powers, particularly for thermal reasons.

[0151] The optimal output impedance of transmit and receive amplification chains is typically 20 ohms. Impedance matching can be used for radar signals, which are powerful signals, and impedance mismatch between the output of a low-power amplification chain (delivering, for example, telecommunications or jamming signals) and the excitation point to which it is coupled is acceptable, as energy efficiency is lower in this case.

[0152] Alternatively, the high-power and low-power transmission amplification chains have distinct optimal output impedances. The impedance matching described above for the high-power transmission amplification chains can then be performed for the low-power transmission amplification chains.

[0153] Each of these chains includes at least one transmit amplifier, for example, a power amplifier. A high-power transmit amplification chain includes at least one high-power amplifier 114a (delivering a signal as on the figure 1 ) or 114 (delivering a differential signal) and a low power transmission amplification chain includes at least one lower power transmission amplifier 218a (intended to receive an asymmetric signal as in la1) or 218 (suitable to receive a differential signal as in the following figures).

[0154] On the figure 21 The reflection coefficient or standing wave ratio of feed point 1 is represented by dashed lines when only this point is excited, and by solid lines the reflection coefficient of the same point when points 1 and 2 are simultaneously excited by their respective transmission amplification chains. This occurs when the impedance of the first port is 20 ohms, the impedance of the second point 2 is 50 ohms, and the output impedance of the second transmission amplification chain is 500 ohms. It can be seen that even with this very high impedance, the reflection coefficient of the first point is only very slightly affected by the excitation of the second port. The signals emitted by the two excitation points are only very slightly affected by each other, which allows for the simultaneous transmission of both types of signals.

[0155] Advantageously, each high-power transmission amplification chain has a narrow bandwidth, while the low-power transmission amplification chain has a wide bandwidth. This is because high-power radar signals require a narrower frequency spread than lower-power jamming or telecommunication signals.

[0156] The antenna according to the second embodiment can have several variants with planar radiating devices arranged as in the figures of the first embodiment and having an associated processing circuit. The transmission circuit in each case comprises two transmission circuits coupled respectively to the first and second sets of points.

[0157] The emission circuit of each of the respective figures 14 to 20 includes the emission circuit of each of the respective figures 1 to 12 (except figures 6 et 9 ), which constitutes the high-power transmission circuit, coupled to the points of the first set, as well as a low-power transmission circuit coupled to the points of the second set. The low-power transmission circuit is identical to the high-power transmission circuit except for the power rating. For example, on the figure 13 The 200a transmission circuit includes the 110a transmission amplification chain of the figure 1 , which here is the high power transmission amplification chain coupled to point 1. The 200a transmission circuit also includes a low power transmission amplification chain 220a coupled to point 2.

[0158] The 200 transmission circuit of the 1000a antenna of the figure 14 differs from that of the figure 3 in that it comprises a low power emission amplification chain 220 comprising a low power amplifier 218 coupled to the pair of points 6+, 6- of the second set to excite these points symmetrically.

[0159] There figure 15 represents another variant of the 1000b antenna combining the elements of figures 13 And 14 and comprising a 200b emission circuit.

[0160] The 200c transmission circuit of the 1000c antenna of the figure 16 differs from that of the figure 5 in that it includes emission circuit A of the figure 15 coupled to the points of the first set 1a+, 1a-; 2a+, 2a-; 3a+, 3a- and 4a+, 4a-, forming the high-power transmission circuit and being powered by a source SOU1, and a low-power transmission circuit C powered by another source SOU2. The low-power transmission circuit C is identical to circuit A except for the power levels of the transmission amplification chains. The four transmission amplification chains of the low-power transmission circuit 231, 232, 233, 234 are coupled to the respective point pairs 1b+, 1b-; 2b+, 2b-; 3b+, 3b- and 4b+, 4b- of the second set.Circuit C includes transmit phase-shifting means 225, 226, each comprising at least one phase shifter, enabling the introduction of a first transmit phase shift between the signal applied to the first pair 1b+, 1b- and the signal applied to the second pair 2b+, 2b-, and the introduction of this same first transmit phase shift between the signal applied to the pair 3b+, 3b- and the signal applied to the pair 4b+, 4b-. The signals delivered by the phase shifter 225 are applied to the inputs of channels 231 and 233, and those delivered by the phase shifter 226 are applied to the inputs of channels 232 and 234. The phase shifters 225 and 226 receive as input a signal from the same source SOU2, delivering a signal distributed between the two phase shifters by means of a splitter 222. Each set of points of the... figure 16 This allows for eight times more power transmission than a single-point excitation solution, while also enabling specific impedance matching between high-power and low-power signals. This configuration allows independent control of the polarization of both high-power and low-power transmissions, and enables the transmission of these different power levels in two different directions. This solution allows for the coverage of transmission sidelobes by other transmissions close to, but outside, the receive band. This prevents interference in the sidelobes, making it a weapon against repeater jammers.

[0161] Advantageously, the first phase shift introduced in transmission between the excitation signals of the points in the second set of points is adjustable. This phase shift can be adjusted independently of the first phase shift introduced in transmission between the excitation signals of the first set of points. This phase shift is advantageously adjustable by means of the adjustment device 35.

[0162] Advantageously, the pointing phase-shifting means allow for the introduction of adjustable global phase shifts between the excitation signals applied to the points of the second set of excitation points of the respective elementary antennas of the antenna. For example, the control device 36 generates a control signal SC comprising global signals controlling the introduction of global phase shifts on the signals received at the input of each phase shifter.

[0163] The 1000d antenna of the figure 17 differs from that of the figure 16 by the 200d emission circuit. The 200d emission circuit includes a high-power Ad emission circuit identical to that of the figure 7 The 200d transmission circuit includes a low-power transmission circuit Bd, identical to the Ad circuit except for the power levels, and connected to the points of the second set of points. This Bd circuit includes four lower-power transmission amplification chains 231, 232, 233, 234 than chains 21, 22, 23 and 24, and connected respectively to the point pairs 1b+, 1b-; 2b+, 2b-; 3b+, 3b- and 4b+, 4b- of the second set. The phase shifting means allow a first phase shift in emission to be introduced between the excitation signals applied to the pairs of excitation points 1b+, 1b- and 2b+, 2b- and a second phase shift in emission between the excitation signals applied to the pairs of points 3b+, 3b- and 4b+, 4b-, these two phase shifts in emission being able to be different.

[0164] These phase-shifting means comprise four phase shifters 127a, 127b, 128a, 128b. Phase shifters 127a and 127b each receive a signal from the same SO3 source, apply respective phase shifts to this signal, and deliver input signals to channels 231 and 232. Phase shifters 128a and 128b each receive a signal from the same SO4 source, apply phase shifts to this signal, and deliver input signals to channels 233 and 234. The signals from the SO3 and SO4 sources pass through respective splitters 222a and 222b before being injected into the inputs of the phase shifters 127a, 127b, 128a, 128b.

[0165] The phase shifts introduced between the excitation signals applied to pairs 1b+, 1b- and 2b+, 2b-, and between pairs 3b+, 3b- and 4b+, 4b-, can be identical. Alternatively, these signals can be different. This allows the transmission and reception of two waves with different polarizations using the second set of points.

[0166] Advantageously, the phase shifts are adjustable.

[0167] The phase shifts introduced between the emitted signals applied to the point pairs 1b+, 1b- and 2b+, 2b- and between the signals applied to the pairs 3b+, 3b- and 4b+, 4b- can advantageously be adjusted independently. The polarizations of the elementary waves emitted by the first quadruple of points 1b+, 1b-, 2b+, 2b- and by the second quadruple of points 3b+, 3b-, 4b+, 4b- of the second set can then be adjusted independently.

[0168] Advantageously, the so-called pointing phase-shifting means allow the introduction of initial global phase shifts between the excitation signals applied to the excitation signals of the first quadruplets of points 1b+, 1b-, 2b+, 2b- of the respective second sets of elementary antennas, and second adjustable global phase shifts between the excitation signals of the second quadruplets of points 3b+, 3b-, 4b+, 4b- of the respective second sets of elementary antennas in the array. The first and second global phase shifts applied to the excitation signals of the second sets can be different. It is then possible to simultaneously transmit four beams in four different directions using the two sets of points. For example, two radar signals can be transmitted in two different directions and / or with different polarizations, or two jamming signals in two different directions and / or with different polarizations.For example, one can conduct communication within a band, protect lobes and scatters, and also have two radar beams in different directions. One can also have transmissions with different polarizations or with polarization agility in the transmission.

[0169] Advantageously, the overall phase shifts in transmission and / or reception are adjustable.

[0170] Advantageously, the overall phase shifts applied to the two sets of points are independently adjustable. The pointing directions are also independently adjustable.

[0171] In the non-limiting example of the figure 17 The pointing phase shifting means include the control device 36 generating a control signal SC comprising various signals commanding the introduction of the aforementioned phase shifts (global and non-global) to be applied to the signals received at the input of the various phase shifters and transmits these signals to the adjustment device 35 so that it commands the phase shifters to introduce these phase shifts on the signals they receive.

[0172] The method of implementation of the figure 18 differs from that of the figure 16 in that the radiating element 11e of the radiating device 10e comprises a first set of points including only the first quadruple of points 1a+, 1a-, 2a+ and 2a- and a second set of points including only the first quadruple of points 1b+, 1b- and 2b+ and 2r-. The associated emission circuit 200e differs from that of the figure 16 in that it only includes the part of the processing circuit coupled to these excitation points. figures 19 And 20 differ from the realization of the figure 18 by the arrangements of the excitation points identical to those of the figures 8 and respectively 10. An arrangement of excitation points as on the figure 11 is also a possibility.

[0173] On the figures 13 In the following diagrams, for clarity, only the receiving circuit is shown. The antenna may also include a receiving circuit. Each point or pair of points can be coupled to a receiving amplification chain in addition to the transmitting amplification chain, allowing the processing of signals from the point or pair of points. Phase-shifting means in the receiving circuit may be provided to ensure phase shifts between signals from the same points as the phase shifts introduced by the transmitting phase-shifting means on the excitation signals. This allows the polarization of the received signals to be adjusted. Means for introducing overall phase shifts in the receiving circuit may also be provided to allow the direction of the receiving antenna to be changed.

[0174] In one variant, the second set of points is identical to that of the figures 5 And 7: 1a+, 1a-, 2a+, 2a-, 3a+, 3a-, 4a+, 4e. The emission circuit advantageously includes the portion of the 200c circuit of the figure 16 or the 200d circuit of the figure 17 which is coupled to these points. The first set of points is identical to that of the figure 20 : 1b+, 1b-, 2b+, 2r. The emission circuit advantageously includes the 200th circuit portion of the figure 20 which is coupled to these points.

[0175] Thus, in the second embodiment, each point in the first set of points is coupled to a high-power transmission amplification chain, and each point in the second set is coupled to a lower-power transmission amplification chain. The points in the first set are not coupled to the low-power transmission amplification chains, and the points in the second set are not coupled to the high-power transmission amplification chains.

[0176] The processing circuits are advantageously implemented using MMIC technology. Preferably, SiGe (Silicon Germanium) technology is used. Alternatively, GaAs (Gallium Arsenide) or GaN (Gallium Nitride) technology is employed. Advantageously, the transmit and receive amplification chains of the same elementary antenna are implemented on the same substrate. This reduces the overall size and facilitates the integration of the amplification chains at the rear of the planar radiating device 10.

[0177] Advantageously, in embodiments not limited to those shown in the figures, each amplification chain of the first type is associated with an amplification chain of the second type. These amplification chains are coupled to respective excitation points. The excitation points are distributed such that the two amplification chains associated with each other are designed to emit or receive, through these respective excitation points, respective elementary waves polarized linearly along the same direction. In other words, this direction is common to both amplification chains. In other words, each of the amplification chains associated with each other is coupled to a set of at least one excitation point so as to emit or detect an elementary wave polarized linearly along a direction. This direction is the same for both coupled amplification chains.

[0178] This configuration allows the elementary antenna to simultaneously transmit and detect a linearly polarized total wave in the same direction, or to simultaneously transmit linearly polarized total waves in the same direction, using either type of amplification chain without phase shifters. This mode of operation is the most common. Therefore, phase shifters can be eliminated from the embodiments shown in the figures. In other words, the amplification chains can be devoid of phase shifters, which reduces the cost and size of the elementary antenna and improves integration efficiency.

[0179] Each amplification chain is coupled to a single excitation point for asymmetric excitation or to a pair of excitation points for differential excitation.

[0180] On the figures 1 à 4 And 13 à 15These excitation points are arranged so that they all lie on one of the lines D1 or D2. When an amplification chain is coupled to two excitation points, these points are arranged symmetrically with respect to the center C. The polarizations detected or emitted by means of these points are linearly polarized along the line on which the points are arranged.

[0181] On the figures 11 à 12 And 20 The excitation points are arranged so that they all lie on the lines D1 and D2. When an amplification chain is coupled to two excitation points, these points are arranged symmetrically with respect to the center C. The two points of the same pair are arranged on the same line and are therefore intended to emit or detect an elementary wave polarized linearly along this line.

Claims

1. Elementary antenna (1, 1a) comprising a planar radiating device (10, 10a) comprising a substantially plane radiating element (11, 11a) and a transmit and receive circuit (20, 20a) comprising at least one amplification chain of a first type (110a) and at least one amplification chain of a second type (120a), each amplification chain of the first type being coupled to at least one excitation point (1) of a first set of at least one excitation point of the radiating element and each amplification chain of the second type being coupled to at least one point (2) of a second set of excitation points of the radiating element, the excitation points of the first and second set being distinct and the amplification chain of the first type being different from the amplification chain of the second type so that they exhibit different amplification properties, the transmit and receive circuit (20, 20a), comprising: - at least one transmit amplification chain (110a) able to deliver signals intended to excite the radiating element, each transmit amplification chain being coupled to at least one point of the first set of at least one excitation point of said radiating element; - at least one receive amplification chain (120a) able to amplify signals arising from the radiating element, each receive amplification chain being coupled to at least one point of the second set of at least one excitation point of said radiating element, the excitation points (1, 2) being positioned and coupled to the respective amplification chains in such a way that each amplification chain is loaded substantially by its optimal impedance, the impedance loaded on each amplification chain being the impedance of the chain formed by the radiating device coupled to the amplification chain and by each feed line coupling the radiating device to the amplification chain; - at least said transmit amplification chain (110a) coupled to one point or two points of the first set exhibits an output impedance which is substantially the conjugate of the radiating device's impedance presented to said transmit amplification chain at said point or between the two points of the first set, and / or - at least one receive amplification chain (120a) coupled to one point or two points of the first set exhibits an output impedance substantially conjugate to the radiating device's impedance presented to said amplification chain in reception at said point or between the two points of the second set.

2. Elementary antenna (1000, 1000a) comprising a planar radiating device (10, 10a) comprising a substantially plane radiating element (11, 11a) and a transmit circuit (200) comprising at least one amplification chain of a first type (110, 110a) and at least one amplification chain of a second type (220, 220a), each amplification chain of the first type (110, 110a) being coupled to at least one excitation point (1) of a first set of at least one excitation point of the radiating element and each amplification chain of the second type (220, 220a) being coupled to at least one point (2) of a second set of excitation points of the radiating element, the excitation points (1, 2) of the first and second set being distinct and the amplification chain of the first type being different from the amplification chain of the second type so that they exhibit different amplification properties, the transmit circuit (200) comprising: - at least one so-called high-power transmit amplification chain (114, 114a) able to deliver signals intended to excite the radiating element, each high-power transmit amplification chain being coupled to at least one point of the first set of at least one excitation point of said radiating element; - at least one second so-called low-power transmit amplification chain (218, 218a), of lower power than the first power amplification chain, able to deliver signals intended to excite the radiating element, each low-power transmit amplification chain being coupled to at least one point of the second set of at least one excitation point of said radiating element, the excitation points being positioned and coupled to each high-power transmit amplification chain (114, 114a) in such a way that each high-power amplification chain is loaded substantially by its optimal impedance, the impedance loaded on each high-power amplification chain being the impedance of the chain formed by the radiating device coupled to the amplification chain and by each feed line coupling the radiating device to the high-power transmit amplification chain; at least said high-power transmit amplification chain (114, 114a) coupled to one point or two points of the first set exhibits an output impedance which is substantially the conjugate of the radiating device's impedance presented to said transmit amplification chain at said point or between the two points of the first set.

3. Elementary antenna according to any one of the preceding claims, in which the excitation points of the first set and of the second set exhibit distinct impedances.

4. Elementary antenna according to any one of the preceding claims, in which the impedance of each excitation point of the first set is less than the impedance of each excitation point of the second set.

5. Elementary antenna according to any one of the preceding claims, in which each amplification chain of the first type is associated with an amplification chain of the second type, these amplification chains being coupled to excitation points disposed so as to transmit or receive respective elementary waves linearly polarized in one and the same direction.

6. Elementary antenna according to any one of the preceding claims, in which the radiating element is defined by a first straight line (D1) passing through a central point (C) of the radiating element and a second straight line (D2) perpendicular to the first straight line (D1) and passing through the central point (C), the excitation points being distributed solely over the first and / or on the second straight line.

7. Elementary antenna according to the preceding claim, in which the excitation points are distributed solely over the first and over the second straight line, the radiating device comprising two slots extending longitudinally according to the first straight line (D1) and the second straight line (D2), the two slots ensuring the coupling of all the excitation points.

8. Elementary antenna according to any one of the preceding claims, in which at least one set taken from among the first set (1a+, 1a-, 2a+, 2a-) and the second set (1b+, 1b-, 2b+, 2b-) comprises at least one pair of excitation points, the pair of excitation points comprising two excitation points coupled to the transmit and / or receive circuit in such a way that a differential signal is intended to flow between the radiating device and the transmit circuit.

9. Elementary antenna according to the preceding claim, in which at least one set taken from among the first set and the second set comprises a first quadruplet of excitation points, the radiating element being defined by a first straight line (D1) passing through a center (C) of the radiating element and a second straight line (D2) perpendicular to the first straight line (D1) and passing through the center (C), the excitation points of each first quadruplet of excitation points comprise a first pair of excitation points composed of excitation points (1a+, 1a-; 1b+, 1b-) disposed in a substantially symmetric manner with respect to said first straight line (D1) and a second pair of excitation points composed of excitation points disposed in a substantially symmetric manner with respect to said second straight line (D2).

10. Elementary antenna according to the preceding claim, in which the excitation points of the first quadruplet of points are situated some distance from the first straight line (D1) and from the second straight line (D2).

11. Elementary antenna according to claim 9, in which each set comprises a first quadruplet of excitation points situated on the first straight line (D1) and on the second straight line (D2).

12. Elementary antenna according to claim 9, in which each set consists of a first quadruplet of points, the excitation points of each first quadruplet of points being situated on just one side of a third straight line (D3) situated in the plane defined by the radiating element, passing through the central point (C) and being a bisector of the angle formed by the first and the second straight line.

13. Elementary antenna according to any one of claims 9 to 11, in which said set comprises a second quadruplet of excitation points situated some distance from the first straight line (D1) and from the second straight line (D2) comprising: a third pair composed of excitation points (3a+, 3e) disposed in a substantially symmetric manner with respect to said first straight line (D1), the points of the third pair of points (3a+, 3a-) being disposed on the other side of the second straight line (D2) with respect to the first pair of excitation points (1a+, 1e) of said set, a fourth pair composed of excitation points (4a+, 4a-) disposed in a substantially symmetric manner with respect to said second straight line (D2), the points of the fourth pair of points (4a+, 4a) being disposed on the other side of the first straight line (D1) with respect to the second pair of excitation points (1a+, 1a-) of said set.

14. Elementary antenna according to the preceding claim, in which each set taken from among the first set and the second set comprises a first and a second quadruplets of points.

15. Elementary antenna according to any one of claims 13 to 14, comprising phase-shifting means making it possible to introduce a first phase-shift between a first signal applied, or arising from, the first pair of the excitation points and a second signal applied to, or respectively arising from, the second pair of excitation points and a second phase-shift of said set, which may be different from the first phase-shift, between a third signal applied to, or respectively arising from, the third pair or arising from the third pair of excitation points of said set and a fourth signal applied to, or respectively arising from, the fourth pair of excitation points of said set.

16. Elementary antenna according to any one of claims 13 to 14, the first quadruplet of points and the second quadruplet of points of at least one set being excited by means of signals of distinct frequencies or being summed separately.

17. Antenna comprising several elementary antennas as claimed in any one of the preceding claims, in which the radiating elements form an array of radiating elements.

18. Antenna according to the preceding claim in that it depends on claim 13, comprising pointing phase-shifting means thereof make it possible to introduce first global phase-shifts between signals applied to the, or arising from the, first quadruplets of points of at least one set of points of the respective elementary antennas and second global phase-shifts between signals applied to the, or respectively arising from the, second quadruplets of points of said set of points of the respective elementary antennas, it being possible for the first and the second global phase-shifts to be different.

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