Title of the invention: ELEMENTARY MICRORSTRIP ANTENNA AND ANTENNA

NETWORK

The present invention relates to the field of antennas

electromagnetic network type and in particular active antennas. It applies in particular to radars, electronic warfare systems (such as radar detectors and radar jammers) as well as communication systems or other multifunction systems.

[0002] A so-called network antenna comprises a plurality of elementary antennas which may preferably be of the microstrip type, also called paved antennas or "patch antenna" in English terminology. These cobblestone antennas comprise a stack of layers of dielectric substrates provided with metal tracks, spaced where appropriate by non-etched materials or substrates.

The technology of elementary microstrip antennas makes it possible to produce very compact antennas, in particular compact electronic scanning array antennas, and simpler to produce and therefore less expensive than other types of antennas (waveguides, Vivaldi ...).

[0004] An elementary microstrip antenna conventionally comprises a radiating element placed on a dielectric layer arranged above a conductive plane serving as a ground so as to constitute a resonator. The elementary antenna also comprises a power distribution device making it possible to excite the radiating element from an input signal. The radiating device is coupled to its excitation by metallized hole (called via) or by a slot. The electromagnetic slot coupling makes it easier to generate a wide frequency band. It also makes it possible to avoid any connection via between the radiating elements and the excitation, which simplifies the manufacture of the elementary antenna.

[0005] There are conventionally provided excitation means capable of exciting

simultaneously the radiating device according to two orthogonal linear polarizations. This makes it possible to choose the most suitable polarization for a

given environment (by combining these 2 polarizations with an appropriate amplitude phase relationship).

[0006] Elementary antennas are subject to a certain number of constraints.

[0007] They generally have a narrow frequency band, typically a few percent. In the case of elementary antenna arrays

microstrip, intended to operate over an extended frequency band which may be greater than one octave, several frequencies of

resonance.

The array antennas form an array of elementary antennas whose pitch is λ Fmax / 2, where λ Fmax is the smallest wavelength corresponding to the maximum frequency Fmax of the band, which is a strong constraint on the dimensions of the elementary antennas.

In order to obtain a microstrip antenna of lesser complexity, and therefore of

limited cost, it is preferable to restrict the number of metallized layers and the number of bonds from one layer to another, made by vias.

A practical solution to increase the width of the bandwidth of

the elementary antenna consists in increasing the volume of the antenna, therefore the height (the thickness), the lateral dimensions being limited by the pitch of the network. Simply increasing the height between the radiating device and the ground plane however leads to parasitic phenomena when placing within a network (transverse propagation of undesirable modes). The conventionally adopted solution consists in using several superimposed radiating elements. This type of stacking is called a double superimposed patch (DPS) in the case of two radiating elements.

To avoid, in the working frequency band, distortions of the

shape and angular pointing of the radiation pattern of the DPS, a symmetrical excitation of two excitation points is provided by means of a power distributor for each of the orthogonal linear polarizations.

In order to avoid intersections of the printed lines, one solution consists in forming the two power distributors on different planes of the microstrip antenna.

In a first case disclosed in the article Wideband and wide scan phased array microstrip patch antennas for small platforms, EuCAP 2007 conferences, by Erickson et al, the two faces of the same dielectric substrate layer are each occupied by a power distributor. The two power distributors include branches whose projections on a plane

perpendicular to the stacking direction intersect. These branches are orthogonal in order to reduce the coupling between the distributors. Each of the distributors comprises two branches which meet outside the surface covered by each of the radiating elements. This configuration is incompatible with the networking of the elementary antenna with a tight mesh (mesh of the order of l ^ 3C / 2).

In an exemplary embodiment disclosed in the article'Air-Cooled, Active Transmit / Receive Panel Arraÿ, IEEE 2007 Radar Conference, by A. Puzella et al, the distributors are arranged on different planes spaced in the direction of 'stacking. Vias are necessary to pass the signals to the second distributor through the layer containing the first distributor, through a ground plane separating the planes of the two couplers. This generates a strong asymmetry on the geometry and therefore on the behavior of the two linear polarizations.

An object of the present invention is to limit at least one of the drawbacks listed above.

To this end, the invention relates to an elementary antenna of the type

microstrip, comprising a stack of layers, the elementary antenna being suitable for being in a planar configuration in which the layers are substantially planar and perpendicular to a stacking axis along which the layers are stacked, the stack comprising a first radiating element conductor and an excitation device coupled to the first radiating element so as to allow excitation of the radiating element according to two orthogonal linear polarizations, the power distribution device comprising:

- a first elementary excitation device configured and coupled to the first radiating element so as to be able to excite a first pair of excitation points formed of a first excitation point and a second point

excitation arranged on a first straight line of the first radiating element, the first elementary excitation device comprising a first conductive line, a second conductive line and a first power distributor capable of distributing a power of an input signal received in an entry / exit point of the first power distributor on the first conductive line and the second conductive line,

- a second elementary excitation device configured and coupled to the first radiating element so as to be able to excite a second pair of excitation points formed of a third excitation point and a fourth excitation point arranged on a second straight line of the first radiating element, the second elementary excitation device comprising a third conductive line, a fourth conductive line and a second power distributor capable of distributing a power of an input signal received at an input point / output of the second power distributor on the third conductive line and the fourth conductive line,

the first, second, third and fourth conductive lines being interposed between the first radiating element and the first and second power distributors along the stacking axis, the first power distributor and the second power distributor being coplanar.

Advantageously, the first conductive line is opposite the first excitation point, the second conductive line is opposite the second excitation point, the third conductive line is opposite the third excitation point and the fourth line conductor is opposite the fourth point of excitation.

Advantageously, the first conductive line and the second line

conductive line extend linearly perpendicular to the first straight line, and the third conductive line and the fourth conductive line extend linearly perpendicular to the second straight line.

Advantageously, the first conductive line and the second line

conducting are coplanar, the third conducting line and the fourth conducting line being coplanar and distant from the first conducting line and from the second conducting line in the stacking direction.

Advantageously, the first power distributor is connected to the first conductive line and to the second conductive line at access points of the power distributor whose orthogonal projections on the first radiating element are distant from the first excitation point and the second excitation point along the second straight line, and in which the second power distributor is connected to the third conductive line and to the fourth conductive line at access points of the power distributor with orthogonal projections on the first radiating element are distant from the third point of excitation and from the fourth point of excitation along the first straight line.

Advantageously, the power distributors are Wilkinson distributors, each power distributor comprising two S-shaped branches, first moving away from each other from the junction point to two parts. then approach each other to the respective ends of a resistor by which the branches are connected, then moving away from each other again to join respective access points of the distributor of power, the end parts being distant from each other by a distance greater than the distance separating the point of junction of the resistance.

Advantageously, the first distributor and the second distributor are

separated from each other by a straight line being an orthogonal projection of a bisector of the first straight line and the second straight line on the plane of the distributors.

Advantageously, the first distributor and the second distributor are

symmetrical to each other with respect to the line. As a variant, the first and second distributors are asymmetrical with respect to the line.

Advantageously, a surface delimiting the first and the second

power distributors is substantially rectangular, each of the first and second power distributors comprises a common branch

comprising an input / output point and being connected to two branches, each of the two branches being coupled to one of the conductive lines via an access point of the branch, a straight line connecting the access points of each power distributor s' extending parallel to and near a first side of the rectangle and an entry / exit point of the power distributor being closer to another side of the rectangle parallel to the first side than said straight line.

Advantageously, the first radiating element comprises a center, the first excitation point and the second excitation point being positioned symmetrically with respect to the center, and the third excitation point and the fourth excitation point being positioned symmetrically with respect to the center.

Advantageously, the elementary antenna comprises a second radiating element superimposed on the first radiating element.

Advantageously, the antenna comprises a first elementary assembly of at least one slot extending linearly opposite the first straight line and facing the first excitation point and the second excitation point and a second elementary assembly of at least one slot extending linearly opposite the second straight line and facing the third point of excitation and the fourth point of excitation, the first set of elementary elements of at least one slot and the second elementary set at least one slot making it possible to couple the excitation device and the first conductive radiating element.

The invention also relates to an array antenna comprising a plurality of elementary antennas according to the invention.

Advantageously, the elementary antennas form an array of elementary antennas.

Other characteristics and advantages of the invention will become apparent on reading the detailed description which follows, given by way of non-limiting example and with reference to the appended drawings in which:

Figure 1 schematically shows an exploded view of an example

elementary antenna according to the invention comprising conductive planes stacked in a stacking direction,

[0032] FIG. 2 schematically represents these conductive planes in section along a plane parallel to the stacking direction,

[0033] FIG. 3 schematically represents a projection, on the plane of the first radiating element, of the slots and of conductive lines of the elementary antenna of FIGS. 1 and 2 as well as the projections of the access points and the excitation points ,

[0034] FIG. 4 represents an example of a plan of the distributors of the antenna

elementary,

Figure 5 shows schematically T-distributors.

From one figure to another, the same elements are identified by the same

references.

The invention also relates to an elementary antenna as well as to an array antenna comprising an array of elementary antennas according to the invention.

Figure 1 schematically shows an exploded view of an example

elementary antenna of the planar type also called microstrip antenna.

The elementary antenna is suitable for being in a planar configuration in

in which the stack comprises a stack of layers which are substantially plane and perpendicular to a stacking direction represented by the z axis.

The elementary antenna can be flexible and be able to present a

curved configuration in which the layers are curved.

In the remainder of the text, we will describe the arrangement of the antenna in its

flat configuration.

The stack comprises parallel conductive planes, spaced according to

the z axis which is orthogonal to them. A sectional view of the elementary antenna is shown in Figure 2. In order not to overload Figures 1 and 2, only the conductive planes are shown.

Intervals are formed between the successive conductive planes. These gaps each include at least one layer of a dielectric substrate which may, for example, be a layer of air or foam.

The elementary antenna A comprises a radiating device B of the superimposed double patch type, comprising:

- an upper intermediate ground plane 3 (by ground plane is meant a conductive plane acting as a ground plane),

- a first radiating element 1 surmounting the upper intermediate ground plane 3,

- a second radiating element 2 surmounting the first radiating element 1.

The first radiating element 1 is called excited block and the second

radiating element 2, which is coupled by proximity to the first radiating element 1, is called a director block. The double superimposed patch is adjusted to achieve a double resonator.

Each radiating element 1, 2 is in the form of a conductive plate. It has, for example, a substantially rectangular shape as shown in Figure 1. As a variant, each radiating element can have a different shape (square, disc, etc.). Whatever the geometry of each radiating element, it is possible to define a center there.

The radiating elements 1, 2 are arranged so that the center C1 of the first radiating element is located opposite the center C2 of the second radiating element, that is to say on the same axis parallel to the direction of stack represented by the z axis.

As a variant, in the case of a lower target bandwidth, the radiating device B comprises a single radiating element.

The elementary antenna A comprises an excitation device C coupled to the

radiating device B so as to make it possible to simultaneously excite the radiating device B according to two orthogonal linear polarizations.

The excitation device C overcomes a lower ground plane D.

The excitation device C comprises:

- a first elementary excitation device 11, v1, v2, L1, L2 configured and coupled to the first radiating element 1 so as to be able to excite a first pair of excitation points of the first radiating element 1, the first pair comprising a first excitation point p1 and a second excitation point p2 arranged on a first straight line D1 of the first radiating element 1,

- and a second elementary excitation device 21, v3, v4, L3, L4 configured and coupled to the first radiating element 1 so as to be able to excite a

second pair of excitation points of the first radiating element, the second pair comprising a third excitation point p3 and a fourth excitation point p4 arranged on a second straight line D2 of the first radiating element 1.

The excitation of the points p1 and p2 by the first excitation device

elementary makes it possible to radiate a polarized wave along the second straight line D2. The excitation of the points p3 and p4 by the second elementary excitation device makes it possible to radiate a wave polarized along the first straight line D1.

The proposed coupling makes it possible to choose the polarization of the total wave emitted by the antenna, the most suitable for a given environment (by combining these two polarizations with an appropriate amplitude phase relationship). It is possible to obtain a total wave circularly polarized in both directions, or linearly in any direction as a function of the phase shifts between these two linearly polarized waves.

The lines D1 and D2 are orthogonal to each other and to the z axis and pass through the center C1.

The points p1 and p2 are symmetrical to one another with respect to the center C1 and the points p3 and p4 are symmetrical to one another with respect to the center C1.

Advantageously, the points p1, p2, p3 and p4 are located at the same

distance from center C1.

As visible in Figures 1 and 2, the invention consists in dividing each

elementary excitation device in two parts:

- two conducting lines L1, L2 (or L3, L4) coupled to the pair of excitation points p1, p2 (or p3, p4) associated with the elementary excitation device,

- And a power distributor 11 (or 21) capable of distributing the power of an input signal on the two conductive lines.

As visible in Figures 1 and 3, each conductive line L1, L2, L3, or L4 passes opposite the excitation point p1, p2, p3 or p4, to which it is coupled. In other words, an orthogonal projection of each conductive line on the plane of the first conductive element 1 passes through the excitation point to which the conductive line is coupled.

According to the invention, the two power distributors 11 and 21 are coplanar, that is to say, placed or etched on the same dielectric substrate layer.

The conductive lines L1, L2, L3 and L4 are interposed between the radiating device B and the power distributors 11 and 21, depending on the direction

stacking z. In other words, the conductive lines L1, L2, L3 and L4 are arranged in planes distant from the power distributors 21, 22 along the stacking axis.

This separation of the power distributors and the excitation lines

leaves greater freedom for the arrangement of the two distributors. It is not necessary for each power distributor to have access points opposite the excitation points associated with the power distributor. According to the invention, it is the conductive lines which must be located opposite these excitation points in order to be able to be coupled with these points.

It makes it possible to choose an arrangement making it possible to limit the dimensions of the power distribution device B in a plane perpendicular to the direction of the stack, which allows tight networking of the elementary antenna.

This arrangement is advantageous for the symmetry of the electrical paths intended to excite the two pairs of points which is favorable to obtaining a perfectly stable and symmetrical radiation pattern throughout the working frequency band. The arrangement of the two distributors of

power on the same plane (or same layer) makes it possible to avoid the installation of vias to pass the current towards one of the distributors through a layer containing the other distributor and two ground planes surrounding this other distributor. This makes it possible to limit the dissymmetry between the excitation branches of the two pairs of points.

Advantageously, the power distributors are separated from the lines.

conductive by a ground plane called the lower intermediate ground plane E, which makes it possible to produce structures of the three-plate type (stripline).

Advantageously, the elementary excitation devices are configured and arranged so that the second elementary excitation device is substantially obtained by rotating the first elementary excitation device by 90 ° around an axis parallel to z and passing by C1. This characteristic makes it possible to obtain a high symmetry between the excitations of the two polarizations due to the symmetry of the electrical paths within the distributors. This favors the coplanar arrangement of the distributors with minimal coupling between these couplers, in particular making it possible to provide shielding vias.

In order to maximize the symmetry of the excitation, the two distributors of

power are symmetrical to each other with respect to a line DB which is an orthogonal projection of a bisector of lines D1 and D2 on the plane of the distributors. This symmetry is an orthogonal symmetry. This solution also makes it possible to arrange shielding / decoupling vias between the two power distributors 11 and 21, as we will see below.

More generally, the two power distributors are separated by the straight line DB.

Furthermore, as shown in Figures 1 and 3, the conductive lines are linear. The conductive lines L1 and L2 are perpendicular to D1 and the lines L3 and L4 are perpendicular to D2. The orthogonality between the two pairs of conductive lines also ensures minimal coupling between these pairs of lines.

It should be noted that in order to avoid a crossing of lines and to arrange the lines in a reduced volume, the conductive lines L1 and L2 are distant from the lines L3 and L4 along the stacking axis z. The lines L1 and L2 are coplanar and included in a first plane P1, perpendicular to the stacking direction z, and the lines L3 and L4 are coplanar and included in a second plane P2, perpendicular to the stacking direction z, distant of the first plane P1 in the stacking direction z. Thus, the second elementary excitation device is obtained substantially by rotating the first elementary excitation device by 90 ° around an axis parallel to z and passing through C1.

The two pairs of conductive lines are for example placed or etched on the two respective faces of a dielectric or insulating substrate.

Advantageously, the thickness of the substrate along the z axis is substantially the thickness necessary and sufficient to provide electrical insulation between the two pairs of lines. The minimum thickness of dielectric or insulating material makes it possible to limit the asymmetry between the excitations of the two pairs of excitation points.

[0070] As a variant, the supply lines are curved.

In Figure 4, each first distributor is a Wilkinson distributor.

The first elementary power distributor 11 comprises three branches including a common branch b and a first branch b1 comprising an access point a1 electrically connected to the conductive line L1 by a via v1 and a second branch b2 comprising a point d access a2 electrically connected to the second conductive line L2 by a via v2.

The second elementary power distributor 21 comprises three

branches including a common branch b 'and a first branch b1'

comprising an access point a1 'electrically connected to line L3 by a via v1' and a second branch b2 'comprising an access point a2' connected

electrically to the second line L4 by a via v2 '. The vias v1, v2, v1 ', v2' extend longitudinally in the stacking direction z as visible in Figures 1 and 2. Each via passes through the lower intermediate ground plane E interposed between the conductive lines and the power distributors 1 1, 21.

The common branch b, b 'of each elementary distributor extends from an input / output point I / O, I / O' on which is intended to be injected the excitation signal to a point junction J, J 'to which the two branches b1 and b2 or b1' and b2 'are connected.

The distributors being resistive distributors of Wilkinson, the two

branches b1 and b2 (b1 'and b2') of each distributor have an S-shape, they first move away from each other from the junction point J (J ') to two end parts e and f (e 'and f), then approach each other to the respective ends of a resistor R (R') through which they are connected and then move away again from one of l 'other to reach the respective access points a1 and a2 (a1' and a2 ').

Advantageously, in order to limit the surface area occupied by each power distributor and to make it possible to position the two Wilkinson distributors in the same plane, the Wilkinson distributors are flattened.

The end parts e and f are distant from each other, along D1, by a distance greater than the distance separating the junction point of the resistor J along the straight line D2. The end parts e 'and f are distant from each other, along D2, by a distance greater than the distance separating the junction point of resistance J' along line D1.

Advantageously, the branches b1 and b2 (b1 'and b2') of each distributor 11 (21) each comprise two elongated rectilinear portions p, q and r, s (p ', q' and r ', s') substantially parallel to each other located between the junction point J (J ') and one of the ends of the resistor.

As a variant, the distributors are of the reactive type, for example T-shaped, are less bulky and easier to produce than the resistive distributors.

Reactive T distributors 31, 41 are shown in Figure 5. They

each comprise a common branch 34, 44 and two branches 32, 33 and 42, 43 connected to a common branch. The two branches 32 and 33 (42 and 43) are collinear. However, taking into account the frequency band to be produced, parasitic resonance phenomena between the power distributors and the DPS, very narrow in frequency, appear, disturbing the operation of the DPS at these frequencies. The use of a resistive distributor, for example, of the Wilkinson type makes it possible to limit these disturbances. It makes it possible to obtain a stable diagram and to eliminate any parasitic resonance in a wide frequency band.

As a variant, the implantation of ring type couplers (called "rat-race hybrid ring coupler" in English terminology) or of ladder type (called "line coupler" in English terminology) can be considered. but these couplers are hardly broadband.

Advantageously, as shown in Figure 3, each access point a1, a2, a3 or a4 is opposite a point of its conductive line L1, L2, L3, or respectively L4 which is closer to 'one end of the line

conductive L1, L2, L3, or respectively L4, that the orthogonal projection of the

excitation point p1, p2, p3, or respectively p4, to which the conducting line L1, L2, L3, or respectively L4 is coupled, on the plane of the conducting line L1, L2, L3, or respectively L4. This therefore frees up the central space, close to the pairs of excitation points, to install the different branches of the elementary distributors opposite the radiating elements and therefore allow tight networking of the elementary antenna.

Advantageously, each power distributor 11, and respectively 21, is configured so that a signal injected on its common branch is divided into two signals of the same power and of the same phase available at its two access points. a1, a2 and respectively a1 ', a2'.

The two branches b1 and b2 of the first power distributor 11 are therefore symmetrical to each other with respect to a projection, on the plane of the power distributors, of a straight line of the first radiating element 1 passing through C1 and parallel to D2. The two branches b1 'and b2' of the second power distributor 21 are symmetrical to each other with respect to a projection, on the plane of the power distributors, of a straight line of the first radiating element 1 passing through C1 and parallel to D2. Thus, the junction points J, J 'are each found on one of these projections. This characteristic favors the symmetry of the excitation.

Advantageously, as shown in Figure 4, at least a portion of the common branch b, b 'of each power distributor 11, 21, elongated in the direction of the junction point J, J' towards the entry point / output I / O or I / O ', extends opposite the radiating elements 1, 2.

In the embodiments of Figures 4 and 5, the radiating elements are delimited by a substantially rectangular surface, for example square, comprising four sides c1, c2, c3, c4; c1 being parallel to c4 and c2 being parallel to c3.

The line d connecting the access points a1, a2 of the first distributor of

power 11 extends parallel to and close to a first side c1 of the square. The line d 'connecting the access points a1', a2 'of the second power distributor 21 extends parallel to and close to c2.

Advantageously, the junction point J and the I / O entry / exit point are located between the line d and the side c4. The junction point J 'and the point

input / output are located between the right of and the side c3. This configuration is advantageous for the compactness of the device.

Advantageously, the input / output I / O point is closer to the side c3 than the points a1 and a2 and the input / output I / O point 'is closer to the side c4 than the points a1' and a2 '.

This is also valid for any rectangle shape.

Advantageously, in order to limit the electromagnetic coupling, the elementary antenna comprises, as visible in FIG. 4, shielding pads extending continuously from the lower ground plane D to the lower intermediate ground plane E. These pads are not shown in the other figures for clarity. These pads include several sets of shielding pads spaced in pairs by a distance much less than the minimum wavelength of the microwave signals conveyed by the elementary antenna.

These shielding pads include first shielding pads 120

arranged and distributed between the two distributors so as to define an electromagnetic shielding between the two power distributors 11 and 21.

Second shielding pads 121, 121 'are arranged between each

distributor 11 and 21 and the edges of the elementary antenna (in a plane

perpendicular to z) so as to define a shielding of the excitation of the elementary antenna with respect to the elementary antennas neighboring the array antenna and with respect to the outside of the array antenna.

Third shielding pads 122, 122 'are arranged between the common branch b, b' and one of the branches b1, b1 ', of each power distributor in order to ensure decoupling between these two branches.

Fourth shielding pads 123, 123 'are arranged around the access points a1, a2, a1', a2 'to form coaxial transmission media with the corresponding vias v1, v2, v1', v2 '. These studs are, for example, arranged in a circle or in an arc of a circle.

In the non-limiting case of the Wilkinson distributors of FIG. 4, fourth shielding pads 124, 124 'are arranged between the two portions p and q and between the two portions r and s and between the two portions p' and q 'and between the two portions r' and s' to provide electromagnetic shielding between branches.

In the non-limiting example of Figure 1, the coupling between the device

radiating B and the power distribution device C is made by slot. To this end, the elementary antenna A comprises a set of slots F1, F2, which are for example oblong rectangles, open in the upper intermediate ground plane 3. The set of slots comprises:

a first elementary set of at least one slot F1 extending linearly opposite D1 and facing the excitation points p1 and p2 of the first pair of excitation points,

a second elementary assembly of at least one slot F2 extending linearly opposite D2 and facing the excitation points p3 and p4 of the second pair of excitation points.

Each slot F1 of the first elementary assembly extends linearly along a line parallel to the line D1. Each slot F2 of the second elementary assembly extends linearly along a straight line parallel to the straight line D2.

Advantageously, but not necessarily, each elementary assembly of at least one slot is symmetrical with respect to a point located opposite the center C1 on the z axis.

[0100] In the non-limiting example of FIG. 1, the set of open slots in the upper intermediate ground plane 3 comprises a cruciform slot F. The cruciform slot F is formed of two orthogonal linear slots F1 and F2 crossing each other. next to the center C1.

[0101] Other types of coupling can be envisaged. The coupling is, by

example, realized vias electrically and mechanically connecting the radiating device A and the power distribution device B. These solutions are more bulky. In addition, the slot coupling makes it possible to obtain a good decoupling between the rectilinear polarizations and to do away with the

parasitic radiation generated by vias.

It should be noted that the excitation devices are capable of being used in reception to ensure the reception of the signals polarized according to D1 and D2 and to transmit them to the I / O and I / O 'inputs/outputs.

Claims

[Claim 1] Elementary antenna (1) of the microstrip type, comprising a stack of layers, the elementary antenna being able to be in a planar configuration in which the layers are substantially plane and perpendicular to a stacking axis (z) along in which the layers are stacked, the stack comprising a first conductive radiating element (1) and an excitation device (C) coupled to the first radiating element (1) so as to allow excitation of the radiating element (1) according to two orthogonal linear polarizations, the excitation device (C) comprising:

- a first elementary excitation device configured and coupled to the first radiating element (1) so as to be able to excite a first pair of excitation points, formed of a first excitation point (p1) and a second excitation point (p2) arranged on a first straight line (D1) of the first radiating element (1), the first elementary excitation device comprising a first conducting line (L1), a second conducting line (L2) and a first power distributor (11) capable of distributing a power of an input signal received at an input / output point (I / O) of the first power distributor (11) on the first conductive line (L1) and the second conductive line (L2),the first conductive line (L1) and the second conductive line (L2) extending linearly perpendicular to the first straight line (D1),

- a second elementary excitation device configured and coupled to the first radiating element (1) so as to be able to excite a second pair of excitation points, formed of a third excitation point (p3) and a fourth excitation point (p4) arranged on a second straight line (D2) of the first radiating element (1), the second elementary excitation device comprising a third conducting line (L3), a fourth conducting line (L4) and a second power distributor (21) capable of distributing a power of an input signal received at an input / output point (I / O ') of the second power distributor (21) on the third conductive line (L3) and the fourth conductive line (L4),the third conducting line (L1) and the fourth conducting line extending linearly perpendicular to the second straight line (D2),

the first, second, third and fourth conductive lines being interposed between the first radiating element (1) and the first and second power distributors (11, 21), along the stacking axis (z), the first power distributor (11) and the second power distributor (21) being coplanar.

[Claim 2] Elementary antenna (1) according to claim 1, in which the first conductive line (L1) is opposite the first excitation point (p1), the second conductor line (L2) is opposite the second point d excitation (p2), the third conductive line (L3) is opposite the third excitation point (p3) and the fourth conductor line (L4) is opposite the fourth excitation point (p4).

[Claim 3] Elementary antenna according to any one of

preceding claims, wherein the first conductor line (L1) and the second conductor line (L2) are coplanar, the third conductor line (L3) and the fourth conductor line (L4) being coplanar and distant from the first conductor line (L1) and of the second conductive line (L2) in the stacking direction (z).

[Claim 4] Elementary antenna according to any one of

preceding claims, in which the first power distributor (11) is connected to the first conductive line (L1) and to the second conductive line (L2) at access points of the power distributor with orthogonal projections on the first element radiating (11) are distant from the first excitation point (p1) and from the second excitation point (p2) along the second straight line (D2), and in which the second power distributor is connected to the third conductive line (L3 ) and to the fourth conductive line (L4) at access points of the power distributor whose orthogonal projections on the first radiating element (11) are distant from the third excitation point (p3) and from the fourth excitation point (p4) along the first line (D1).

[Claim 5] An elementary antenna according to any one of the preceding claims, in which the power distributors are Wilkinson distributors, each power distributor comprising two S-shaped branches, first deviating from one of them. 'other from the junction point up to two parts then move closer to each other to the respective ends of a resistor (R) through which the branches are connected, then moving apart again one on the other to reach respective access points of the power distributor, the end parts being distant from each other by a distance greater than the distance separating the junction point (J) from the resistor (R ).

[Claim 6] Elementary antenna (1) according to any one of

preceding claims, wherein the first distributor (11) and the second distributor (21) are separated from each other by a straight line (DB) being an orthogonal projection of a bisector of the first straight line (D1) and of the second straight line (D2) on the plane of the distributors.

[Claim 7] Elementary antenna (1) according to claim

previous one, in which the first distributor (11) and the second

distributor (21) are symmetrical to each other with respect to the line (DB).

[Claim 8] Elementary antenna according to any one of

preceding claims, a surface delimiting the first and second power distributors is substantially rectangular, each of the first and second power distributors (11) comprises a common branch (b) comprising an entry-exit point and being connected to two branches, each of the two branches being coupled to one of the conductive lines via an access point of the branch, a straight line connecting the access points of each power distributor extending parallel to and close to a first side of the rectangle and a input / output point of the power distributor being closer to another side of the rectangle parallel to the first side than said straight line.

[Claim 9] An elementary antenna according to any preceding claim, wherein the first radiating element comprises a center (C1), the first excitation point (p1) and the second excitation point (p2) being positioned symmetrically with respect to the center (C 1), and the third excitation point (p3) and the fourth excitation point (p4) being positioned symmetrically with respect to the center (C1).

[Claim 10] An elementary antenna (1) according to any one of the preceding claims, comprising a second radiating element superimposed on the first radiating element.

[Claim 11] Elementary antenna according to any one of

preceding claims, comprising a first elementary assembly of at least one slot (F1) extending linearly opposite the first straight line (D1) and facing the first excitation point (p1) and the second excitation point ( p2) and a second elementary set of at least one slot (F2) extending linearly opposite the second straight line (D2) and facing the third excitation point (p3) and the fourth excitation point (p4 ), the first elementary assembly of at least one slot and the second elementary assembly of at least one slot making it possible to couple the excitation device and the first conductive radiating element.

[Claim 12] An array antenna comprising a plurality of elementary antennas according to any one of the preceding claims.