FR2984613A1 - OPTICALLY TRANSPARENT PRINTED ANTENNA AND OPTICALLY TRANSPARENT ANTENNA NETWORK - Google Patents

Abstract

The invention relates to an optically transparent antenna comprising: a lower substrate supporting the ground plane of the antenna; an intermediate substrate; an upper substrate; the intermediate substrate being disposed between the lower substrate and the upper substrate, the substrates being optically transparent and preferably glass; the antenna being characterized in that the ground plane comprises an optically transparent conductive deposit, the conductive deposit being the ground plane facing the intermediate substrate; and in that the antenna further comprises: - a radiating assembly disposed between the intermediate substrate and the upper substrate; two transmission lines formed by an optically transparent conductive deposit on the surface of the intermediate substrate facing the ground plane and which respectively extend from two opposite edges of the intermediate substrate to the radiating assembly so that when the lines of transmission are fed, they cause radiation of the radiating assembly.

Description

GENERAL TECHNICAL FIELD The invention relates to the field of telecommunications and particularly that of antennas printed for mobile cellular networks. It relates to a printed antenna and in particular an optically transparent printed antenna whose metal planes consist of an optically transparent conductive deposit, preferably in the form of a grid and printed on substrates, preferably of glass, and it also relates to an antenna assembly comprising several antennas. optically transparent.

STATE OF THE ART A printed antenna usually comprises a ground plane, a radiation plane comprising one or more radiating elements and a dielectric substrate (for example air) interposed between the ground plane and the radiation plane. The radiating element (in English, "patch") usually consists of a conductive surface printed on the radiation plane and fed by a microstrip line (in English, "microstrip") printed on the radiation plane or else on another plane disposed between the ground plane and the radiation plane or by coaxial access under the antenna. Networking such antennas provides better directivity. On the other hand, the relative bandwidth remains limited to a few percent and double polarization is only possible with two linear arrays arranged next to one another, which implies having a larger panel. PRESENTATION OF THE INVENTION The invention proposes to overcome at least one of these disadvantages.

For this purpose, the invention proposes an optically transparent antenna comprising: a lower substrate supporting the ground plane of the antenna; an intermediate substrate; an upper substrate; the intermediate substrate being disposed between the lower substrate and the upper substrate, the substrates being optically transparent and preferably glass; the antenna being characterized in that the ground plane comprises an optically transparent conductive deposit, the conductive deposit being the ground plane facing the intermediate substrate; and in that the antenna further comprises: - a radiating assembly disposed between the intermediate substrate and the upper substrate; two transmission lines formed by an optically transparent conductive deposit on the surface of the intermediate substrate facing the ground plane and which respectively extend from two opposite edges of the intermediate substrate to the radiating assembly so that when the lines of transmission are fed, they cause radiation of the radiating assembly. The invention is advantageously completed by the following characteristics, taken alone or in any of their technically possible combination: the radiating assembly consists of two pellets: a first pellet formed by an optically transparent conductive deposit disposed on the surface of the intermediate substrate facing the upper substrate; a second pellet formed by an optically transparent conductive deposit disposed on the surface of the upper substrate facing the intermediate substrate, the first and second pads being opposite each other, the dimensions of the second pellet being smaller than those the first pellet; the radiating assembly consists of: a support substrate comprising a first pellet formed by an optically transparent conductive deposit disposed on the surface of the support substrate facing the upper substrate; a second wafer formed by an optically transparent conductive deposit disposed on the surface of the upper substrate facing the support substrate, the first and second wafers being opposite each other, the dimensions of the second wafer being smaller than those of the first pellet; the first and second pellets are square patches, the length of the L_P1 side of the first chip being given by L P1 150000 1 / min -3 (f) where fm ,,, and fmax are respectively the minimum and maximum frequencies of the desired bandwidth for the desired operation and where Erleff is the effective relative permittivity of the intermediate substrate surrounding the first pellet, wherein Erleff <Cry with Cri the relative permittivity of the intermediate substrate and wherein the length of the L_P2 side of the second pellet is such that L P2 <L P1; the radiating assembly is further constituted by a third pellet formed by a conductive deposit on the surface of the support substrate facing the intermediate plane, the dimensions of the third pellet being greater than those of the first and second pellets; the first, second and third pellets are square patches, the length of the L_P3 side of the third pellet being given by L P3- 150000 / min + -4 U. where fmin and fmax are respectively the minimum and maximum frequencies of the strip; desired pass-through for the intended operation and where Erleff is the effective relative permittivity of the support substrate surrounding the third wafer and wherein Erleff <Cry with Cri the relative permittivity of the support substrate, wherein the length of the L_P1 side of the first wafer is such that L_P1 <L_P3 and the length of the L_P2 side of the second pellet is such that L_P2 <L P1; the surface of the intermediate substrate facing the support substrate comprises an optically transparent conductive deposit in which two slots have been formed by removal of the conductive deposit in a given pattern, said surface of the intermediate substrate acting as an additional ground plane for the antenna; the slots are H-shaped oriented at an angle of 45 ° relative to each other and in which the transmission lines respectively extend from two opposite edges of the intermediate substrate and terminate by overlapping the H bar of the slots below; the pads are square patches and in which the transmission lines respectively extend from two opposite edges of the intermediate substrate terminate below the pad disposed above the intermediate substrate only; it comprises a metal frame for maintaining in position the ground plane, the lower and upper substrates; The upper substrate comprises a ring formed by an optically transparent deposit framing the second pellet; the metal frame is in electrical contact with the crown. The invention also relates to a set of optically transparent antennas comprising a plurality of optically transparent antennas according to the invention arranged in a linear array and in which the ground plane of each antenna is formed on a substrate common to all the antennas, the intermediate substrate of each antenna is defined from a substrate common to all the antennas, the upper substrate of each antenna is defined from a substrate common to all the antennas.

The set of antennas of the invention may comprise two phase-shifting devices, each phase-shifter having an input and n outputs, n being a number less than or equal to the number of antennas, inserted between a coaxial access and the microstrip lines. supplying one of the two polarizations of the antennas isolated or grouped two by two and provided with a manual and electrical device for progressive phase shift of the radiating elements, the phase-shifting devices being arranged opposite each other. In addition, the set of antennas of the invention may comprise two transparent phase-shifting devices, sandwiched between the lower substrate and the upper substrate, the phase-shifter devices being arranged opposite each other. The invention also relates to a method of manufacturing an optically transparent antenna according to the invention, comprising steps of: - providing a lower substrate supporting a ground plane, an intermediate substrate and an upper substrate the substrates being optically transparent and preferably of glass, the intermediate substrate being intended to be disposed between the substrate supporting the ground plane and the upper substrate; providing a radiating assembly intended to be disposed between the intermediate substrate and the upper substrate; depositing a transparent optical conductive material on the lower substrate, said deposit forming the ground plane; depositing an optically transparent conductive material on the surface of the intermediate substrate in front of the ground plane to define two transmission lines which respectively extend from two opposite edges of the intermediate substrate to the radiating assembly so that when the transmission lines are energized, they cause radiation of the radiating assembly. Finally, the invention relates to a method of manufacturing a set of optically transparent antennas comprising a plurality of optically transparent antennas according to the invention arranged in a linear array and in which the ground planes of each antenna are formed on a substrate common to all the antennas and wherein the intermediate and upper substrates are respectively formed by a substrate common to all the antennas. The invention has many advantages. The antenna of the invention is broadband, that is to say up to about 45% of relative bandwidth and double polarization allowing the association of several antennas, in the form of a linear network for form a panel, directive and dual polarization antenna. The use of this type of antennas allows the implantation of the base stations of the cellular radio networks in the high-traffic areas of the mobile terminals while preserving the urban architecture: - by the integration of the antenna-panels on the facades historic or protected buildings; - the fusion of antenna-panels in the glazed panels of contemporary buildings. PRESENTATION OF THE FIGURES Other features, objects and advantages of the invention will emerge from the description which follows, which is purely illustrative and nonlimiting, and which should be read with reference to the appended drawings, in which: FIG. three-dimensional arrangement of an optically transparent antenna according to a first embodiment of the invention; FIG. 2 illustrates a sectional view of an optically transparent antenna according to a first embodiment of the invention; FIG. 3 illustrates a view from above of the optically transparent antenna of FIG. 1; FIG. 4 illustrates a three-dimensional view of an optically transparent antenna according to a second embodiment of the invention; FIG. 5 illustrates a sectional view of an optically transparent antenna according to a second embodiment of the invention; FIG. 6 illustrates a view from above of an optically transparent antenna according to a second embodiment of the invention; FIG. 7 illustrates a sectional view of an optically transparent antenna according to a third embodiment of the invention; Zo - Figure 8 illustrates a top view of the ground plane of the optically transparent antenna according to the first embodiment of the invention; FIG. 9 illustrates a view from above of the intermediate substrate of the optically transparent antenna according to the first embodiment of the invention; FIG. 10 illustrates a view from below of the intermediate substrate of the optically transparent antenna of the invention; FIG. 11 illustrates a bottom view of the upper substrate of the optically transparent antenna of the invention; Figure 12 illustrates a bottom view of the intermediate substrate of the optically transparent antenna according to the second and third embodiments of the invention; FIG. 13 illustrates a view from above of the support substrate of the optically transparent antenna according to the second and third embodiments of the invention; FIG. 14 illustrates a bottom view of the support substrate of the optically transparent antenna according to the third embodiment of the invention; FIGS. 15a and 15b illustrate two configurations of an antenna assembly 30 of optically transparent antennas according to the invention; FIGS. 16a, 16b and 16c illustrate different configurations and the corresponding performances of the set of antennas of the invention. In all the figures, similar elements bear identical reference numerals. DETAILED DESCRIPTION OF THE INVENTION The following description is understood to mean by material "optically transparent" a material which is transparent in at least a portion of the visible light range, allowing at least about 30% of that light to pass through, and preferably more than 60% of the light. General description of the optically transparent antenna In general, the antenna of the invention comprises a lower substrate 10 supporting the ground plane of the antenna; an intermediate substrate 20 and an upper substrate 30. The intermediate substrate 20 is disposed between the lower substrate 10 and the upper substrate 30. In addition, the ground plane deposited on the lower substrate 10 comprises a conductive deposit 100 (see FIG. 8) optically transparent, the conductive deposit 100 being on the surface of opposite the intermediate substrate 20. The antenna further comprises metal walls 50a, 50b, 50'a, 50'b surrounding the substrates 10, 20 and 30, establishing a direct electrical contact between the conductive deposits 100 and 300 '. The antenna further comprises a radiating assembly 200, 300, 400, 400 ', 40 disposed between the intermediate substrate 20 and the upper substrate and two transmission lines 200a, 200b formed by an optically transparent conductive deposit on the surface of the substrate. intermediate 20 opposite the ground plane 100 and which respectively extend from two opposite edges of the intermediate substrate 20 to the radiating assembly so that when the transmission lines 200a, 200b are energized, they cause a radiation of this radiant whole.

The radiating assembly can take different forms depending on the intended applications. Embodiment: Optically Transparent Two-Pad Printed Antenna According to a first embodiment of the invention, the optically transparent printed antenna comprises two pellets. The radiating element consists of a first wafer 200 formed by an optically transparent conductive deposit disposed on the surface of the intermediate substrate 20 opposite the upper substrate 30 and a second wafer 300 formed by an optically transparent conductive deposit disposed on the surface of the substrate the first and second pads facing each other, the dimensions of the second chip 300 being smaller than those of the first chip 200 (see FIGS. 1 and 2). To provide power, it comprises two transmission lines 200a, 200b formed by an optically transparent conductive deposit on the surface of the intermediate substrate 20 opposite the ground plane 100 and which respectively extend from two opposite edges of the intermediate substrate 20 20 towards the center of the intermediate substrate 20 so that when the transmission lines 200a, 200b are energized, they cause radiation of the first and second pellets 200, 300 located above. According to this embodiment, the two transmission lines 200a, 200b are "micro ribbon inverted" transmission lines, that is to say 25 printed under the intermediate substrate 20 having as a ground plane the conductive deposit 100. In addition, the antenna comprises access Aa, Ab to supply power to the transmission lines 200a, 200b. These accesses include coaxial access.

The antenna further comprises metal walls 50a, 50b, 50'a, 50'b at the ends of the substrates 10, 20 and 30, establishing direct electrical contact between the conductive deposits 100 and 300 '. In particular, the antenna comprises four walls 50a, 50b, 50'a, 50'b two walls 50a, 50'a disposed between the upper substrate 30 and the intermediate substrate 20 on the one hand and others of the transmission lines 200a, 200b so as to leave a clearance between the transmission lines 200a, 200b. At the transmission lines 200a, 200b the walls 50a, and 50'a are spaced apart by a spacing D.

In the same way, two walls 50b, 50'b are arranged between the lower substrate 10 and the intermediate substrate 20 with a clearance at the transmission lines 200a, 200b. Preferably, the first wafer 200 and the second wafer 300 are square patches and the transmission lines 200a, 200b respectively extend from two opposite edges of the intermediate substrate 20 and terminate below the first 200 wafer. only (see Figure 3). In this way, in operation, the transmission lines feed the first chip 200 and the second chip 300 then acts as a parasitic element. The two electromagnetic modes TMO1 and TM10 generated by the resonance of the first chip 200 create two electric fields linearly polarized towards the chip 300, polarized with the same orientation created by the edges of the two power supply lines, these fields being orthogonal to each other .

In operation, the two associated pads allow the element to radiate to have a wide bandwidth and the ability to integrate two polarizations, without adding additional elements. This configuration makes it possible in particular to have a set of narrower transparent antennas with a single row of bipolarized elements (instead of two rows) and to operate in an enlarged band encompassing, for example, two frequency bands of the cellular networks, namely the DCS 1800 in the 1700-1900 MHz band and the 3G 2100 in the 1900-2200 MHz band, ie a single antenna for the broadband 1700-2200 MHz. The operation of said broadband pellets is also valid for other operating bands of the telecommunication spectrum. The dimensions of the pellets are relatively fixed. The dimensions of the first wafer 200 are a function of the medium in which it is excited. Knowing the operating frequencies, the medium, and the electrical characteristics of the feed of the first pad 200 and assuming that the first pad has a square geometry, the length of one side L_P1 is approximately given by: 150000 L P1 1) / min -3 (f. (Equation 1) with Erie <Eni (Equation 2) It should be noted that unlike the first pellet 200, there is no formula for approximating the sizing of In fact, the feeding of the second chip 300 is more complex because it does not rely on a transmission line, but on an electromagnetic coupling with the first chip 200. The constraint is that the second chip pastille 300 having a square geometry (square patch) the relation between the length of a side L_P2 of the second patch 300 and the length of a side L_P1 of the first patch 200 is given by: L_P2 <L P1 (Equation 3) The table below described by way of example the 25 design parameters for operation in the DCS-UMTS band (1700-2200 MHz).

Parameter Description Unit Value L P1 Length of the first pellet side 200 mm 45 mm - L P2 Length of the second pellet side 300 mm 36 mm - E rl Effective relative permitivity of the medium surrounding the first pellet 200 Without unit 3,17 611 Relative Permittivity of the Intermediate Substrate 20 and the Upper Substrate Without Unit 4.7 Minimum Frequency of the MHz Bandwidth 1700 MHz fmax Maximum Frequency of the 2200 MHz MHz Bandwidth In addition, the intermediate substrate 20 and the upper substrate 30, preferably both have a thickness of 3.3 mm and a relative permittivity of 4.7 for operation in the above bands.

Moreover, the upper face of the lower substrate 10 and the lower face of the intermediate substrate 20 are spaced apart by a dielectric which is air with a thickness of 3.3 mm. The upper face of the intermediate substrate 20 and the lower face of the upper substrate 30 are spaced apart by a dielectric which is air with a thickness of 14 mm. 2nd Embodiment: Optically Transparent Two-Pad Printed Antenna with a Supporting Substrate According to a second embodiment of the invention, the optically transparent printed antenna comprises two wafers with a support substrate. The radiating element consists of a support substrate 40 suspended at the ends by non-conductive spacers (not shown). It is preferably made of glass, is disposed between the intermediate substrate 20 and the upper substrate 30 and comprises a first pellet 400 formed by an optically transparent conductive deposit disposed on the surface of the support substrate 40 in front of the upper substrate 30 and a second wafer 300 formed by an optically transparent conductive deposit disposed on the surface of the upper substrate 30 opposite the support substrate 40, the first and second wafers 400 and 300 being opposite each other, the dimensions of the second wafer 300 being lower than those of the first pellet 400 (see Figures 4 and 5). Furthermore, to provide power, it comprises an optically transparent conductive deposit 210 on the intermediate substrate 20 and in front of the substrate 40. Two slots 210a, 210b have been formed by removal of the conductive deposit 210 in a given pattern. This optically transparent conductive deposit 210 thus formed acts as an additional ground plane for the antenna.

On the surface of the intermediate substrate 20 facing the ground plane 10, two transmission lines 200a, 200b formed by an optically transparent conductive deposit respectively extend from two opposite edges of the intermediate substrate 20 towards the center of the intermediate substrate 20 when the transmission lines 200a, 200b are energized, they establish a close electromagnetic coupling with the respective slots 210a and 210b, causing in turn a radiation of the first and second pellets above. The transmission lines are conventional microstrip lines (in English, "microstrip fine") on average 50% more compact than the inverted microstrip line of the first embodiment. This transmission line does not degrade the radiation of the antenna because it is masked by the conductive deposit 210. In the same way as for the first embodiment, the antenna comprises two walls 50b, 50'b which are arranged between the lower substrate 10 and the intermediate substrate 20 with a clearance at the transmission lines 200a, 200b (see detailed description above). In this embodiment, the coupling between the transmission lines 200a, 200b and the pellets is indirect and is achieved via the two slots 210a, 210b obtained by removing the conductive deposit 210 according to the determined pattern or any other geometry. In this way, the field transmitted to the radiating elements is of high polarization purity. And a judicious placement of the two slots makes it possible to achieve an important insulation between the two lines 200a and 200b allowing between the two coaxial accesses of the complete antenna a high isolation level (of the order of 40dB). The geometry of the slots 210a, 210b may vary depending on the requirements (bandwidth compromise, channel isolation). With respect to the first embodiment, the antenna according to the second embodiment makes it possible to have a higher polarization purity because of the existence of a conductive deposit masking the parasitic radiation and a mechanism for power supply which is based this time on a coupling by openings in the ground plane. The sizing principle of the pellets is identical to that of the first embodiment. The sizing of the first and second pellets is also based on equations 1 to 3, and on the parameters presented in the table previously described. As an indication, the lower substrates 10, intermediate 20, upper 30, and support 40 have respective thicknesses of 7 mm, 3.3 mm, 2 mm and 3.3 mm, and are made from optically transparent materials, here glass. The upper face of the lower substrate 10 and the lower face of the intermediate substrate 20 are spaced by 3.3 mm of air. The upper face of the intermediate substrate 20 and the lower face of the support substrate 40 are spaced 3.3 mm of air. The upper face of the intermediate substrate 20 and the lower face of the upper substrate 30 are spaced 18 mm of air.

Seventh Embodiment: Optically Transparent Three-Pad Printed Antenna With Supporting Substrate According to a third embodiment of the invention, the optically printed antenna comprises three pads with a support substrate.

The optically transparent printed optical antenna corresponds to that of the second embodiment and is such that the radiating assembly further comprises elements of the radiating assembly of the second embodiment, a third pellet 400 'formed by a conductive deposit on the surface of the support substrate 40 facing the intermediate substrate 20, the Io dimensions of the third pellet 400 'being greater than those of the first and second pellets 400 and 300 (see Figure 7). In this embodiment when the transmission lines 200a, 200b are energized, they establish close electromagnetic coupling with the respective slots 210a and 210b, in turn causing radiation of the first and second pads above. Here again, the sizing principle of the first, second and third pellets of the radiating element is the same as that used previously, although the number of pellets differs. The antenna of this embodiment extends the bandwidth of the second embodiment. Considering the third pellet 400 'square, the length of the side L P3 of the third pellet 400' is given by 150000 L P3 - 1 / min -4 (f with: In <In 25 And as before, the lengths of the pellets above the third pellet are successively decreasing, considering that the first and second pellets 400 and 300 are square-geometrical (square patch), between the length of one side L_P1 of the first pellet 400 and the length of the first pellet. a side L_P3 of the third pellet 400 'has: L P1 <L P3 And between the length of a side L_P2 of the second pellet 300 and the length of a side L_Pl of the first pellet 400, we have L P2 < L P1 The following table describes the sizing parameters for operation in the DCS-UMTS-LTE band (1700 - 2700 MHz) as an example Parameter Description Unit Value L P3 Length of mm 32 side third pad 400 'L P1 Length of the side of mm 45 the first pellet 400 L P2 The length of the 38 mm side the second pellet 300 E Relative permittivity Without an effective 3,17 unit of the medium surrounding the support substrate 40 E r 1 Without unit 4.7 Relative permittivity of the support substrate 40 Minimum frequency MHz 1700 MHz of the desired bandwidth fmax Maximum frequency MHz 2700 MHz of the desired bandwidth The operation of said broadband wafers is also valid for other bands of operation of the telecommunications spectrum. As an indication, the lower substrates 10, intermediate 20, upper 30, and support 40 have respective thicknesses of 7 mm, 3.3 mm, 2 mm and 3.3 mm, and are made from optically transparent materials, here of glass. The upper face of the lower substrate 10 and the lower face of the intermediate substrate 20 are spaced by 3.3 mm of air. The upper face of the intermediate substrate 20 and the lower face of the support substrate 40 are spaced 3.3 mm of air. The upper face of the intermediate substrate 20 and the lower face of the upper substrate 30 are spaced 18 mm of air. Crown Regardless of the embodiment, the antenna may comprise a ring 300 'formed by an optically transparent deposit framing the patch 300. The ring makes it possible to control the opening of the radiation pattern in the horizontal plane of the antenna . Its geometry is defined by two parameters: the width W_C of the crown and the width of its opening O_C. The opening of the crown O_C is approximated by: 900000 rce (imin f.) The width of the crown W_C, for its part, is approximated by: WC 150000 rc f (J min e, max) The table below describes for example, the sizing parameters of the first embodiment. Parameter Description Unit Value 0 C Opening of the ring mm 190 mm WC Width of the ring mm 30 mm 0 C 2 9846 13 18 Erce Actual relative permittivity of the medium surrounding the ring and the upper substrate 30 Without unit 1.33 Minimum frequency of the desired bandwidth MHz 1900 MHz fmax Maximum frequency of the desired bandwidth MHz 2200 MHz Antenna assembly Antennas according to any one of the embodiments described above may constitute the radiating elements of an antenna array. Figures 15a and 15b illustrate an antenna array of ten antennas A1, A2, A3, A4, A5, A6, A7, A8, A9, A10 (schematized by broken lines) arranged in a linear array (one below 10 the other). As illustrated in these figures, the antenna assembly comprises a lower panel forming the ground plane 10, an intermediate panel 20 corresponding to the intermediate substrate, optionally a support panel 40 corresponding to the support substrate and an upper panel corresponding to the substrate The network is linear and comprises two independent accesses Sa, Sb feeding two sides of each antenna to obtain a linear and orthogonal double polarization. Each radiating element of each antenna comprises two transmission lines, each line being connected directly or via a "Y" coupler via microstrip lines 51a, 51b, 52a, 52b, 53a, 53b, 54a, 54b, 55a, 55b grouping two antennas and printed on the same substrate, to a phase shifter device D (I), D'Il), the antenna array having a phase shifter device Dit D'Il) by polarization.

The microstrip lines 51a, 51b, 52a, 52b, 53a, 53b, 54a, 54b, 55a, 55b are constituted by an optically transparent conductive deposit. Each phase shifter device Dit D'il) has a coaxial output 7/16 'connections via a coaxial cable 60a, 60b low losses.

It is recalled that a phase shifter device Dit D'il) is a device which makes it possible to incline the main lobe of radiation of the network towards the ground (according to the arrows represented in FIGS. 15a and 15b) on the two polarizations, this functionality is also referred to by its English name "ti / t".

Tilt is used to reduce interference between the cells of the different base stations when the antenna array has this function, while optimizing their radio coverage which makes a compromise between the level of interference between the cells and the radio coverage. In urban areas, the tilt is normally between 2 ° and 8 ° but there are important ranges up to 14 °. Dit D'el) phase shifters are designed to be housed along the two long sides of the network to minimize their visual impact. Each phase shifter device Dit, D'il) is connected to a device of two rods 70, 70 'made of a different dielectric material from the air associated with a motor M. The motor M is an electric motor also called RET for " Remote Electrical Tilt ") which is conventionally controlled from a supervision system of several antennal sets. The motor M is housed in one end of the antenna array in an open area of the intermediate lens and between the two coaxial connectors S 7/16 '. The phase shift is obtained by modifying the dielectric medium of the transmission lines inside the phase shifter by the penetration of the rods 70, 70 '.

In particular by actuating the rack 90 (manually or via the motor M having a wheel 80), the two rods 70, 70 'enter the phase shifters (according to the arrows) so as to produce phase variations at the output of each line. The middle outputs are not affected by the phase shift which simplifies the implementation of the phase shifter device. Preferably, the main lobe of the radiation pattern of the antenna assembly can be inclined by moving the phase-shifting devices in three positions POS1, POS2, POS3. In order to further reduce the visual impact of these phase shifters, it is envisaged to make them almost transparent by using the same association "transparent conductive deposit - glass" used to constitute the optically transparent antenna. In the embodiment of FIG. 15b, the internal transmission lines of the phase-shifter device are produced by microstrip lines in transparent conductive deposition, which are preferably used to receive on each side the phase shifter D (I), D'Il) in the form of a glass block which will allow a change in the dielectric medium, the phase shifter D (I), D'Il) is in this transparent embodiment. The phase shift function is obtained by varying the air / glass propagation medium. Indeed, it is known that the phase shift of a transmission line can be obtained from the change of propagation medium of this line. The propagation medium of the transmission lines will then be progressively immersed in a dielectric with a constant Er which will vary from 1 to 4.7 (that of the glass, that is to say that of the phase-shifter device). FIG. 16 illustrates several radiation diagrams for several phase shift values: 2 °, 4 ° and 8 °. As can be seen in this figure, the radiation pattern becomes more and more inclined as the phase shift increases. Optically transparent conductive deposit The ground plane 10, the intermediate substrate 20, the upper substrate 30 and the support substrate 40 are transparent dielectric substrates of the glass or plexiglass type.

The optically transparent conductive deposits 100, 100 ', 200, 200a, 200b, 300, 300', 400, 400 'are for example indium oxide doped with tin ITO or doped tin oxide AgHT silver deposited on a plastic film (for example a polyester film).

To improve transparency conductive deposits can be replaced by a conductive mesh. The mesh used has a number of parameters that influence optical transparency. Note that the size of the mesh can vary locally depending on the electromagnetic activity of the radiating element. For this purpose, reference can be made to patent application FR 10/50392, "An optically transparent printed antenna with a mesh ground plane". Similarly, the mesh of the transmission lines will be tightened to ensure its power function, the tightening of the mesh may be maximum close to the output. It is specified that the conductive mesh is for example made of iron, nickel, chromium, titanium, tantalum, molybdenum, tin, indium, zinc, tungsten, platinum, manganese, magnesium, lead, preferably silver, copper, gold or aluminum or metal alloy chosen according to the electrical conductivity. It typically takes the form of a grid whose ratio between the size of the openings of the mesh and the width of the tracks of the mesh defines the level of optical transparency of the ground plane, the feed line of the feed plane and the radiation plan. Of course, it is not limited to the use of a mesh grid, other forms are of course possible (see also FR 10/50392). It is specified here that the dimensioning of the mesh is characterized by its pitch (or periodicity), by the width and thickness of the conductive tracks (or by the opening made in the pitch).

The conductive deposit can be obtained by various means.

The conductive deposit may thus consist of a metal foil (foil) or a conductive thin layer deposited on an inorganic transparent substrate (silica, glass, sapphire, ...) or organic (plexiglass, polymethylpentene, polycarbonate, polyethylene terephthalate , BCB, ...). It will be noted that the use of low loss flexible polymer substrates facilitates the transfer of the antenna on or in the appropriate supports (window, showcase, vehicle windshield ...). The conductive deposit can be made physically (PVD), for example by spraying, evaporation under vacuum, laser ablation, etc. or by other means, for example chemical deposition (silver plating, copper plating, gilding, aluminide, tin plating, nickel plating, etc.), by screen printing, by electrolytic deposition, by chemical vapor deposition (CVD, PECVD, OMCVD, ...), etc. The openings of the conductive mesh in the sheet or metal film can be made by standard photolithography from a photomask or mask transferred by laser writing on a reserve and the associated chemical etching, or by tampongraphy followed by a chemical etching , or by ion etching through a mask. The mesh can also be directly produced by screen printing through a screen (in English, "screen printing"), by jet printing of a conductive ink (and annealing associated), by electroforming, by direct writing via decomposition under laser beam of an organometallic, etc. METHOD OF MANUFACTURING THE ANTENNA AND THE CORRESPONDING SETUP To manufacture the antenna described above, a manufacturing method comprises steps of providing a lower substrate 10 supporting the ground plane, an intermediate substrate 20 and an upper substrate 30, the substrates being optically transparent and preferably of glass. The intermediate substrate is intended to be disposed between the ground plane and the upper substrate.

In addition, the method comprises a step of providing a radiating assembly 200, 210, 300, 400, 400 ', 40 to be disposed between the intermediate substrate (20) and the upper substrate (30). The radiating assembly is also optically transparent and can take one of the forms described above. Then the method comprises a step of depositing an optically transparent conductive material on the lower substrate so as to define the ground plane. Then comes a step of depositing an optically transparent conductive material on the surface of the intermediate substrate 20 opposite the lower substrate 10 to define two transmission lines 200a, 200b which respectively extend from two opposite edges of the intermediate substrate 20. In addition, the conductive deposit forming the transmission lines 200a, 200b is such that when the radiating assembly is disposed between the lower substrate and the upper substrate and the transmission lines will be energized, they cause radiation of the radiating assembly. . The set of antennas is manufactured in a similar way, the difference being that the various stages of deposition of the optically transparent conductive material make it possible to define the antenna array: the ground planes of each antenna, the upper and lower substrates as well as the radiating assemblies are obtained from optically transparent substrates common to all the antennas.

Claims (17)

REVENDICATIONS1. An optically transparent printed antenna comprising: a lower substrate (10) supporting the ground plane of the antenna; an intermediate substrate (20); an upper substrate (30); the intermediate substrate (20) being disposed between the lower substrate (10) and the upper substrate (30), the substrates being optically transparent and preferably of glass; the antenna being characterized in that the ground plane (10) comprises an optically transparent conductive deposit (100), the conductive deposit (100) being the ground plane (10) facing the intermediate substrate (20); and in that the antenna further comprises: - a radiating assembly (200, 210, 300, 400, 400 ', 40) disposed between the intermediate substrate (20) and the upper substrate (30); two transmission lines (200a, 200b) formed by an optically transparent conductive deposit on the surface of the intermediate substrate (20) facing the ground plane (10) and which respectively extend from two opposite edges of the intermediate substrate (20) to the radiating assembly so that when the transmission lines (200a, 200b) are energized, they cause radiation of the radiating assembly. Optically transparent printed antenna according to claim 1, in which the radiating assembly consists of two pellets (200, 300): a first patch (200) formed by an optically transparent conductive deposit disposed on the surface of the intermediate substrate ( 20) facing the upper substrate (30); a second wafer (300) formed by an optically transparent conductive deposit disposed on the surface of the upper substrate (30) opposite the intermediate substrate (20, 20 '), the first (200) and second (300) pellets being opposite each other, the dimensions of the second pellet (300) being smaller than those of the first pellet (200). 5 An optically transparent printed antenna according to claim 2, wherein the pellets are square patches and wherein the transmission lines (200a, 200b) respectively extending from two opposite edges of the intermediate substrate (20) terminate at below the pellet disposed above the intermediate substrate only. 10 An optically transparent printed antenna according to one of claims 2 to 3, wherein the first (200) and second (300) pellets are square patches, the length of the L_P1 side of the first patch being given by where fmin and fmax 150000 6 x [f '' + -3 (f 1 - f, 'Ù,) 1 are respectively the minimum and maximum L_P 1 frequencies of the desired bandwidth for the desired operation and where Erleff is the effective relative permittivity of the medium. surrounding the first wafer (200), wherein F.sub.eff.sub.r <Er1 with Er1 the relative permittivity of the intermediate substrate (20) and wherein the length of the L_P2 side of the second wafer is such that L_P2 <L_P1. An optically transparent printed antenna according to claim 1, wherein the radiating assembly comprises: a support substrate (40) comprising a first wafer (400) formed by an optically transparent conductive deposit disposed on the surface of the support substrate ( 40) facing the upper substrate (30), a second wafer (300) formed by an optically transparent conductive deposit disposed on the surface of the upper substrate (30) facing the support substrate (40), the first (400) and second (300) pellets being opposite each other, the dimensions of the second pellet (300) being smaller than those of the first pellet (400). An optically transparent printed antenna according to claim 5, wherein the radiating assembly is further comprised of a third wafer (400 ') formed by a conductive deposition on the surface of the support substrate (40) facing the intermediate substrate ( 20), the dimensions of the third wafer (400 ') being greater than those of the first (400) and second (300) wafers. An optically transparent printed antenna according to one of claims 5 to 6, wherein the first (400), second (300) and third pastilles (400 ') are square patches, the length of the L_P3 side of the third patch being given by X f + -4. (fur -finin) 1 where frnin and frnax are respectively the minimum and maximum frequencies of the desired bandwidth for the desired operation and where Erl eff is the effective relative permittivity of the medium surrounding the third pellet (400 ') and wherein Erieff <Cry with Cri the relative permittivity of the support substrate (40), wherein the length of the L_Pl side of the first (400) pellet is such that L_P1 <L_P3 and the length of the L_P2 side of the second pellet (300) is such that L_P2 <L_P 150000 L_P3 An optically transparent printed antenna according to one of claims 5 to 7, wherein the surface of the intermediate substrate (20) facing the support substrate (40) comprises an optically transparent conductive deposit (210) in which two slots (210a, 210b) have been formed by removing the conductive deposit (210) in a predetermined pattern, said surface of the intermediate substrate acting as an additional ground plane for the antenna. An optically transparent printed antenna according to claim 8 wherein the slots (100a, 100b) are H-shaped oriented at an angle of 45 ° to one another and in which the transmission lines (200a, 200b) respectively extend from two opposite edges of the intermediate substrate (20) and terminate by overlapping the H-bar of the slots (200a, 200b) below. 10. An optically transparent printed antenna according to one of the preceding claims, comprising a metal frame for holding in position the ground plane, the lower and upper substrates. An optically transparent printed antenna according to one of claims 2 to 10, wherein the upper substrate (30) comprises a ring (300 ') formed by an optically transparent deposit framing the second wafer (300). An optically transparent printed antenna according to claim 11, wherein the metal frame is in electrical contact with the ring gear (300 '). An optically transparent antenna assembly comprising a plurality of optically transparent printed antennas according to one of the preceding claims disposed in a linear array and wherein the ground plane of each antenna is formed on a substrate common to all antennas, the Intermediate substrate of each antenna is defined from a common substrate to all antennas, the upper substrate of each antenna is defined from a common substrate to all antennas. An optically transparent printed antenna assembly according to claim 13, comprising two phase shifter devices, each phase shifter having an input and n outputs, n being a number less than or equal to the number of antennas, each phase shifter being inserted between a coaxial access and microstrip lines supplying one of the two polarizations of the antennas isolated or grouped two by two, the assembly being provided with a manual and electrical device for progressive phase shift of the radiating elements, the phase-shifting devices being arranged one in facing each other. The optically transparent printed antenna assembly of claim 13 including two transparent phase shifter devices sandwiched between the lower substrate and the upper substrate, the phase shifter devices being disposed opposite each other. 16. The method of manufacturing an optically transparent printed antenna according to one of claims 1 to 12, comprising steps of: providing a lower substrate (10) supporting a ground plane, an intermediate substrate (20) and an upper substrate (30), the substrates being optically transparent and preferably glass, the intermediate substrate being adapted to be disposed between the substrate (10) supporting the ground plane and the upper substrate (30). providing a radiating assembly (200, 210, 300, 400, 400 ', 40) to be disposed between the intermediate substrate (20) and the upper substrate (30); depositing a transparent optical conductive material on the lower substrate, said deposit forming the ground plane; depositing an optically transparent conductive material on the surface of the intermediate substrate (20) facing the ground plane (10) to define two transmission lines (200a, 200b) which extend respectively from two opposite edges of the intermediate substrate ( 20) to the radiating assembly so that when the transmission lines (200a, 200b) are energized, they cause radiation of the radiating assembly. 17. A method of manufacturing a set of optically transparent printed antennas comprising a plurality of optically transparent antennas according to one of claims 1 to 12 disposed in linear array and wherein the ground planes of each antenna are formed on a substrate common to all the antennas and wherein the intermediate and upper substrates are respectively formed by a substrate common to all the antennas.