EP1142063B1 - Telecommunication device with shaped electronic scanning arrays and associated telecommunication terminal - Google Patents

Description

The present invention relates to the field of telecommunications, especially microwave, and concerns more particularly a telecommunications device with scanning networks conformed electronics. It also relates to a telecommunications in a satellite constellation system and a wireless communication terminal for communicating with domestic equipment.

So far, commercial satellite communications were almost entirely carried out by geostationary satellites, particularly interesting because of their unchanging relative positions in the sky. However, the geostationary satellite has major drawbacks such as significant attenuations of transmitted signals related to distance separating the user antennas of the geostationary satellite (of the order of 36,000 kilometers, the corresponding losses then amounting to around 205 dB in the Ku band) and transmission delays (typically of the order of 250 ms to 280 ms) thus becoming clearly noticeable and annoying especially for real-time applications such as telephony, videoconferencing, etc. In addition, the geostationary orbit, located in the equatorial plane, poses a visibility problem for high latitudes, angles of elevation becoming very low for regions close to the poles.

• l'utilisation de satellites sur des orbites elliptiques inclinées, le satellite étant alors quasi stationnaire au-dessus de la région située à la latitude de son apogée pendant une durée pouvant atteindre plusieurs heures,
• la mise en oeuvre de constellations de satellites en orbites circulaires, notamment en orbite basse ("Low Earth Orbit" ou LEO en langue anglaise) ou en orbite moyenne ("Mid Earth Orbit" ou MEO en langue anglaise), les satellites de la constellation défilant à tour de rôle en visibilité du terminal usager pendant une durée allant d'une dizaine de minutes à environ une heure.

The alternatives to the use of the geostationary satellite are:

• the use of satellites on inclined elliptical orbits, the satellite then being almost stationary above the region situated at the latitude of its apogee for a period of up to several hours,
• the implementation of constellations of satellites in circular orbit, in particular in low orbit ("Low Earth Orbit" or LEO in English) or in medium orbit ("Mid Earth Orbit" or MEO in English), satellites of the constellation scrolling in turn in visibility of the user terminal for a period ranging from ten minutes to approximately one hour.

In both cases, the service cannot be provided permanently by a single satellite, the continuity of the service requiring scrolling above of the service area of several satellites succeeding each other.

We already know, in particular by application EP-A-0512487 (Alcatel Space), a telecommunications device with scanning networks electronics comprising M alignments of radiating sources (13) arranged according to a generator (12) of a surface of revolution and a switch coupling said M alignments to N lines of a network of combiners / dividers (NLM), said switch being able to supply N adjacent alignments at a given time; a single phase shifter being connected to each generator of radiant elements.

La présente invention concerne un perfectionnement aux structures ci-dessus.

La présente invention a pour objet un dispositif de télécommunication à réseaux à balayage électronique du type comportant M premiers alignements (90, ...97) de premières sources rayonnantes (5) en réseaux, lesdites sources étant alignées selon une génératrice d'une surface de révolution, et un commutateur (12) couplant lesdits M alignements à N lignes d'un réseau (14) de combineurs / diviseurs, avec N<M, ledit commutateur étant apte à alimenter N alignements adjacents à un instant donné de manière à contrôler la direction en azimuth, caractérisé en ce qu'il comporte de plus des déphaseurs (10) intercalés entre les sources rayonnantes d'une même génératrice et un contrôleur (40) pour contrôler le commutateur et les déphaseurs (10) de manière à ajuster le diagramme de rayonnement résultant desdits N alignements selon la direction en élévation.

On the other hand, US Pat. No. 4,605,932 describes a radiating structure with scanning arrays comprising first and second arrays of sources arranged according to surfaces of revolution symmetry superposed to operate around a first and a second central frequency:

The present invention relates to an improvement to the above structures.

The present invention relates to a telecommunication device with electronic scanning networks of the type comprising M first alignments (90, ... 97) of first radiating sources (5) in networks, said sources being aligned along a generator of a surface. of revolution, and a switch (12) coupling said M alignments to N lines of a network (14) of combiners / dividers, with N <M, said switch being able to supply N adjacent alignments at a given time so as to control azimuth steering, characterized in that it further comprises phase shifters (10) interposed between the radiating sources of the same generator and a controller (40) to control the switch and the phase shifters (10) so as to adjust the radiation pattern resulting from said N alignments in elevation direction.

According to an additional characteristic, seconds phase shifters (190, 191, 192, 193) each control a phase shift additional of the N alignments supplied, said phase shift varying according to a phase gradient so that each source of N supplied alignments is supplied in an equiphase manner.

According to yet another additional characteristic, it further includes M 'second alignments of second sources radiant arranged on a second substrate superimposed on the first substrate, said first and second sources being arranged so as to not to be facing each other, the second alignments of second radiating sources operating at a central frequency different from that of early alignments from early sources radiating.

According to a preferred embodiment, at each position of the satellite, at a given time, in the radio radiation space of the device, corresponds a pair of values (N, ΔΦ), N corresponding to N adjacent alignments supplied by said switch and ΔΦ representing the value of the phase shift introduced by said first phase shifters to the sources of N alignments.

• la figure 1 représente un schéma en perspective d'un dispositif selon l'invention,
• la figure 2.a représente un mode de réalisation du dispositif selon l'invention alors que les figures 2.b et 2.c représentent des variantes du mode de réalisation de la figure 2.a selon des spécifications différentes du système de satellites,
• la figure 3 représente une pluralité d'alignements selon un mode de réalisation de l'invention,
• les figures 4.a et 4.b représentent des variantes schématiques du mode de réalisation de la figure 3,
• la figure 5.a représente une variante de réalisation d'un alignement selon l'invention alors que la figure 5.b représente une succession d'alignements selon cette variante,
• la figure 6 représente une variante du mode de réalisation de la figure 3,
• la figure 7 représente une variante du dispositif selon l'invention,
• la figure 8 représente un mode de réalisation d'un circuit d'émission/réception de signaux selon l'invention,
• la figure 9 représente une variante du dispositif selon l'invention,
• la figure 10.a représente schématiquement les premiers déphaseurs selon l'invention alors que les figures 10.b et 10.c représentent des modes de réalisation de ces déphaseurs.

Other characteristics and advantages of the present invention will emerge from the description of the exemplary embodiments and of the variants which will follow, taken by way of nonlimiting examples, with reference to the appended figures in which:

• FIG. 1 represents a perspective diagram of a device according to the invention,
• FIG. 2.a represents an embodiment of the device according to the invention whereas FIGS. 2.b and 2.c represent variants of the embodiment of FIG. 2.a according to different specifications of the satellite system,
• FIG. 3 represents a plurality of alignments according to an embodiment of the invention,
• FIGS. 4.a and 4.b represent schematic variants of the embodiment of FIG. 3,
• FIG. 5.a represents an alternative embodiment of an alignment according to the invention while FIG. 5.b represents a succession of alignments according to this variant,
• FIG. 6 represents a variant of the embodiment of FIG. 3,
• FIG. 7 represents a variant of the device according to the invention,
• FIG. 8 represents an embodiment of a signal transmission / reception circuit according to the invention,
• FIG. 9 represents a variant of the device according to the invention,
• Figure 10.a schematically shows the first phase shifters according to the invention while Figures 10.b and 10.c show embodiments of these phase shifters.

To simplify the description, the same references will be used in these last figures to designate the elements filling identical functions.

Figure 1 shows a perspective diagram of a device 1 according to the invention. This comprises a conical substrate 2 with vertex O, of half-angle at the top α and radius R on its circular base 3. The substrate itself rests on a conical support, not shown. In this figure, it a plurality of generators 4 has been illustrated connecting the vertex O with the base 3 according to a plan normal to this base. For reasons of clarity, lozenges radiant 5 are only illustrated on one of the generators 4, all of the radiating pellets in a network on a generator forming an alignment, but all the alignments are arranged on the envelope of the cone to cover a 360 ° radiation field. For more details on the alignments, we can refer to the book "Engineering techniques" E3280 Antennas, Chapter 3: Alignments. In FIG. 1, the device 1 receives the signals from a satellite 6 according to a diagram 7. In the configuration as shown, the device 1 receives the satellite without distortion in elevation of sound radiation diagram 7. The depointing is illustrated in dotted lines maximum of this diagram defined by the characteristics of the device for that this has an angle of reception of the satellites in elevation going from 0 ° at 90 °. The depointing in elevation is defined by a phase shift of the radiation pattern for a given group of powered alignments.

Figure 2.a shows schematically an embodiment of the device according to the invention. According to the specifications of this first mode embodiment, the device must cover a radiation field by relative to the horizontal from 0 ° to 90 ° in elevation. In this context, the angle α is determined equal to 45 °. In this way, center networks of phase 80, 81 undergo a phase shift allowing a depointing going from -45 ° 45 ° to optimal viewing axes without offset respective 800, 810.

Figures 2.b and 2.c show variants of the Figure 2.a according to different system specifications of scrolling satellites. In the case of Figure 2.b, where the specification of the system allows an angle of reception of the satellites on the local horizon of 10 °, the angle α is 50 ° whereas, in Figure 2.c, in the case where the satellite system has a large number of satellites passing by according to predefined trajectories, thus ensuring the existence of several satellites in the radiation space at a given time, the angle of minimum capture relative to the local horizon can be set at 40 °, which determines the angle α to a value of 65 °.

FIG. 3 represents a plurality of alignments 90, 91, ... 97 in a network of circular radiating pads 5, two adjacent pads 5 being separated by an adjustable phase shifter 10. Note that, in the following, we will only describe the elements of a network corresponding to the same surface 45, 46 (see FIG. 9), the description of the second network being identical in its constitution, only the positioning of the pellets in look of each network is explained below. In this case, the The network to be described will be the one used for receiving signals. The second network used for transmitting signals will not be described but its constitution remains the same as that of the receiving network (tablets radiant, phase shifters, connections to a switch by terminals 110, ... 117 described below). Each alignment 90, 91, ... 97 has each two ends, one with a radiating patch and the other comprising a radiating patch connected respectively to terminals 110, 111, ... 117 of a switch 12. The switch is connected to a combiner / divider 14 by four supply lines (N = 4) 130, 131, 132, 133. The switch 12 allows thanks to a control signal Sc from a microcontroller 40 to supply four alignments, by example 90 to 93, among the seven (M = 7) alignments of the network. He is at point out that only a limited number of pellets have been shown and alignments for the sake of clarity of the drawings but the number of alignments is of the order of a hundred. The selection of these four alignments 90 to 93 is carried out according to a pre-established selection method from a table contained in a read-only memory 41 and comprising a ephemeris of the positions of the satellites over time and / or taking account of the level of the signals received on the reception circuit. In this last case, the microcontroller has in a read-only memory a threshold value. When receiving signals whose level drops in below the threshold value, the microcontroller controls the supply of four adjacent alignments, for example 91 to 94. In any event, three of the selected alignments must be among the alignments previously fed to allow regular monitoring and smoothly. If the radiation pattern generated by these four alignments does not allow reception with an adequate level, the microcontroller continues its circular switching to four other adjacent alignments until the level requirement greater than the threshold value is met. Of course, the method of selection of N alignments is not limited to the methods described above and can be extended to any other method. The fourth supplied alignments are connected to the four lines 130 to 133 of the combiner / divider whose output / input is connected by a link 15 with a transmission / reception circuit described below. Each alignment 90 to 97 is arranged on the surface of the cone 2 according to a generator 4 thereof. The pellets are excited by feed lines 50, the pellets and the lines 50 being etched on the upper surface of the oriented substrate towards the radiation area of the device. Of course, using two substrate layers, pellets and excitation lines can be engraved on opposite sides.

Figures 4.a and 4.b show variants of the embodiment of FIG. 3. In FIG. 2, the same phase shifter 10 is common to two alignments 900, 901 whereas in FIG. 4.b, the same phase shifter 10 is common to four alignments 902, 903, 904, 905. The supply of the alignments 90, 91, ... 97 can be done, according to the figure 4.a, in groups of two alignments or, according to Figure 4.b, in groups of four, or more. This reduces the total number of phase shifters for the network (typically this number is divided by two, four, ... and generally divided by i), since two, four (generally i) pellets belonging to adjacent alignments have their phase adjusted by the same phase shifter. This grouping of alignments also allows reduce the number of ports 110 to 117, reducing complexity and let alone the cost of the switch. The switch initially comprising M ports for the reception network for the M alignments of the sources of the reception network (M other ports being intended for connections of M source network alignments) and N ports for lines connected to the combiner / divider, can, thanks to the invention, display only m ports for M alignments and n ports for lines connected to the combiner / divider with m and n such that: m <M, m = M / k, and n <N, and n = N / k with k = 2, 4, ... i.

• aux pastilles d'un même réseau qui sont proches du sommet de ne pas être trop proches les uns des autres, minimisant ainsi les interférences,
• d'espacer suffisamment les pastilles d'un même réseau proches du sommet pour ne pas être en regard de pastilles du second réseau selon une coupe normale des surfaces comprenant les sources.

FIG. 5.a represents another variant of an alignment of pads 18. Each pad 18 is rectangular, of constant height L according to the height of the cone 2 and of width W increasing, according to a predefined law, for example linearly, as a function inverse of the distance from the patch to the base 3 of the cone. The consistency of the height L for the same surface allows the patches to operate at the same frequency. On the other hand, the reduction in width W as mentioned above allows:

• to the pellets of the same network which are close to the top not to be too close to each other, thus minimizing interference,
• enough spacing of the pellets of the same network close to the top so as not to be opposite the pellets of the second network according to a normal section of the surfaces comprising the sources.

Figure 5.b represents a succession of pad alignments 18 according to the variant of FIG. 5.a. This estate is arranged on a plane before being shaped into a cone.

FIG. 6 represents a variant of FIG. 3. In FIG. 6, between each line 130, 131, 1.32, 133 and each input / output terminal corresponding to the combiner / divider 14 is a phase shifter 190, 191, 192, 193 allowing additional adjustment of the phases corresponding to each alignment or group of alignments to which it is associated. This adjustment is controlled by the microcontroller 40.

According to a variant of the invention illustrated in FIG. 7, the device -1 has a frustoconical shape. This configuration is interesting for low elevation angles. It is also more suitable for keep almost constant distances between pads belonging to two adjacent alignments. Indeed, in the case of a conical device, the radiating pellets close to the top 0 suffer from being close to them of each other compared to those near the base.

FIG. 8 represents an embodiment of a circuit transmission / reception 20 connected to the combiner / divider 14 of FIG. 3. The latter includes a circulator 21, an input of which is connected to a circuit transmission 22 of signals, an output is connected to a reception circuit 23 signals and an input / output is connected to the combiner / divider 14 via the line 15. The reception circuit 23 successively comprises in the direction signal reception filter, 24 bandpass filter around the central reception frequency, a weak amplifier 25 noise, a mixer 26 receiving on a first input the signal filtered by the filter 24 and amplified by the amplifier 25 and on a second input a output signal from a local oscillator 27. The output of the mixer provides a intermediate frequency signal for an indoor unit of a dwelling not shown on which the transmission / reception device is placed according to the invention. The transmission circuit 22 comprises in the transmission direction signals a mixer 28 whose first input receives a signal in indoor unit intermediate frequency, a second input from a local oscillator 29 transposing the signal into transmission frequency mixer inlet. The latter's output signal attacks the input a power amplifier 30. The amplifier output is connected to the input of a bandpass emission filter 31 filtering said signal around the transmission frequency to deliver it to the input of circulator 21. Thus, the circuit 23 is an intermediate frequency conversion circuit while circuit 22 is a transmission frequency conversion circuit, usually at microwave frequencies. The outlet of the mixer 26 delivering the signal in intermediate frequency for the indoor unit is also connected to the microcontroller 40 which uses the received signal to detect its level as previously explained. Thus, the circuit 20 makes it possible to receive the reception signals from the first reception network described above and to transmit the signals to be transmitted to the second network.

• en vue de pouvoir recevoir deux satellites simultanément. Selon cette variante, un réseau peut être dédié à la réception/émission de signaux relatif à un premier satellite alors que la seconde est dédiée à la réception/émission de signaux relatif à un second satellite. Comme précédemment mentionné, il est nécessaire que les pastilles de chacune des surfaces ne se superposent pas, de sorte que les pastilles de la surface supérieure ne perturbent pas l'émission/ réception de signaux des pastilles de la surface inférieure,
• une surface peut être dédiée à l'émission et la seconde pour la réception, comme précédemment envisagé. On n'utilise alors pas de circulateur mais on a deux accès directs : un à l'emission et un à la réception. Cela permet d'optimiser séparément chaque réseau (fréquence centrale de fonctionnement, largeur de bande, diagramme de rayonnement, etc...). Dans ce cas également, afin de réduire le couplage entre émission et réception, les pastilles ne se superposent pas.

This superposition of several layers of substrates is implemented for several purposes:

• in order to be able to receive two satellites simultaneously. According to this variant, a network can be dedicated to the reception / transmission of signals relating to a first satellite while the second is dedicated to the reception / transmission of signals relating to a second satellite. As previously mentioned, it is necessary that the pellets of each of the surfaces do not overlap, so that the pellets of the upper surface do not disturb the transmission / reception of signals from the pellets of the lower surface,
• one surface can be dedicated to transmission and the second for reception, as previously envisaged. We then do not use a circulator but we have two direct accesses: one to the transmission and one to the reception. This makes it possible to optimize each network separately (central operating frequency, bandwidth, radiation pattern, etc.). In this case also, in order to reduce the coupling between transmission and reception, the pellets do not overlap.

According to a variant described in Figure 9, in order to widen the bandwidth of the device according to the invention, on each network (respectively first and second network) said main network is associated an auxiliary network also comprising radiating pads. He was represented a couple of layers for the same main network. On the layer (called surface) of upper substrate 45 (without ground plane) are engraved tablets superimposed on the tablets of the lower layer 46. Each network of pads of the upper substrate resonates around a center frequency slightly offset from that of the opposite network from which it is located, to allow a widening of the band of operating frequency of the network torque composed of the two main and auxiliary networks opposite.

FIG. 10.a illustrates, framed by dotted lines, a phase shifter 10 of terminals 1, 2, with diodes, for controlling the phase shift ΔΦ between the pads of an alignment, which fixes the deflection of the beam in elevation  such that: ΔΦ = 2Πd * sin / λ.

Figure 10.b is an embodiment of this phase shifter. This one includes variable capacity diodes 341, 342 ("variable identical capacitor "or" varactors "placed in ports 3, 4 of a 3dB / 90 ° hybrid coupler. The microcontroller varies the voltage from polarization of these diodes, which modifies the junction capacity of these last and therefore the reflection coefficient of these diodes. The phase shift between ports 1 and 2 is modified. So the microcontroller continuously controls phase variations of phase shifters.

Figure 10.c shows another embodiment of the phase shifter: it has two varactor diodes 351, 352 placed on the line transmission between ports 1 and 2 and the phase shift between ports 1 and 2 is controlled by the bias voltage of these diodes.

The device according to the invention can be advantageously used, but not exclusively, for reception and / or transmission in a system communication via satellites, especially scrolling, or in a home automation system for the connection between different equipment servants.

Of course, the invention is not limited to the modes of realization and variants as described. Thus the device 1 according to the invention has been described around a conical surface 2. Any other symmetrical surface of revolution perhaps envisaged. In addition, it is also possible a surface 2 with symmetry of revolution truncated in at least one section normal of the surface passing through the central surface axis. In this case of figure, the revolution is no longer total 360 ° but will be partial.

Claims (9)

1. Telecommunications device with electronic scanning arrays of the type comprising M first alignments (90, ...97) of first radiating sources (5) in arrays, the said sources being aligned along a generatrix of a surface of revolution, and a switch (12) coupling the said M alignments to N lines of an array (14) of combiners/dividers, where N < M, the said switch being capable of feeding N adjacent alignments at a given instant ton control the azimuthal direction, characterized in that, in addition, it comprises phase shifters (10) inserted between the radiating sources of the same generatrix and a controller (40) to control the switch and the phase shifters (10) so as to adjust the radiation pattern resulting from the said N alignments according to the elevational direction.
2. Device according to Claim 1, characterized in that the radiating sources are formed by patches etched on a substrate forming the said surface of revolution and directly excited by printed lines which are on the same plane as the said patches.
3. Device according to Claim 1, characterized in that the radiating surface of each radiating source increases with the distance separating the said source from the coupling point (110, ...117) of the alignment (90, ...97) to which the said source belongs with the said switch.
4. Device according to Claims 1 and 2, characterized in that the dimensions of each radiating source are determined such that, along one alignment, it operates at the same predetermined central frequency.
5. Device according to Claims 1 to 4, characterized in that one and the same phase shifter (10) is common to several alignments such that it can adjust the phase of several sources.
6. Device according to Claims 1 to 5, characterized in that second phase shifters (190, 191, 192, 193) each control an additional phase shift of N fed alignments, the said phase shift varying according to a phase gradient such that each source of N fed alignments is fed in an equiphase manner.
7. Device according to Claims 1 to 6, characterized in that the surface of revolution consists of a cone or of a truncated cone.
8. Device according to Claims 1 to 7, characterized in that, in addition, it comprises M' second alignments of second radiating sources placed on a second substrate superimposed on the first substrate, the said first and second sources being placed such that they do not face each other, the second alignments of the second radiating sources operating at a central frequency different from that of the first alignments of the first radiating sources.
9. Device according to one of Claims 1 to 8, characterized in that at each satellite position, at a given instant, in radioelectric radiation space of the device, has corresponding co-ordinates (N, ΔΦ), where N corresponds to N adjacent alignments fed by the said switch and ΔΦ represents the phase shift introduced by the said first phase shifters to the sources of N alignments.

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