MXPA00000471A - Device for transmitting and receiving microwaves subjected to circular polarisation - Google Patents

Abstract

The invention concerns a device for transmitting and receiving microwaves comprising a planar radiating element. Said device is characterised in that the radiating element (60) has, for transmitting and receiving, substantially orthogonal accesses (68, 66), the phase shift of the transmission and reception signals and the shape of the radiating element being such that the transmission and reception signals, whereof the frequencies are different, are subjected to circular polarisation in opposite directions.

Description

DEVICE FOR EMISSION AND RECEPTION OF HYPERFERENCE WAVES, CIRCULARLY POLARIZED The invention relates to an idspositivo emission and reception of microwave waves or circularly polarized microwaves.

Devices of this kind are commonly used in telecommunications systems. These »10 emission and reception devices are usually designed to emit important powers and receive light powers. This is the case, for example, in the telecommunication systems in which the signals are surveyed by geostationary satellites.; fifteen In these devices, the emission frequencies and the reception frequencies are different to prevent the reception signals from being disturbed by the emission signals. It is also necessary to provide filtering means so that in each way, the desired frequency can be received or emitted and the frequency of the other way eliminated. The separation between the signals must be particularly careful when the emission and the reception are simultaneous.

REF. 32361 These devices often contain a waveguide source and a high rejection duplicator in the respective emission and reception bands. They therefore have an important saturation that can not be suitable for all. applications, particularly for terminals of telecommunication systems in which each subscriber must have an emitter and a receiver.

In particular, the ultrafrequency wave emission and reception devices can be used on a regular basis, for both domestic and professional uses, in satellite telecommunication systems.

For example, telecommunication systems of this type are developed for applications called "multimedia". In these systems, a constellation of satellites in low orbits, of altitude between 800 to 1500 km, or medium, altitude between 6000 and 12000 km is expected. The orbits are called "low or medium" as opposed to geostationary satellites whose altitude is 36000 km. The satellites aim to ensure communication between land users. The communications thus transmitted are of a multimedia nature, that is, they concern television signals, audio signals, video, numerical data of all kinds, programs, telephone or telecopy signals. In relation to communications surveyed by geostationary satellites, the low altitude of the satellites reduces the distance of communication and thus the delays due to propagation, which facilitates the inetractivity of these systems. In addition, with constellations, coverage can be optimized, for example by privileging areas of high population density, since a geostationary orbit privileges the areas near the equator.

A terrestrial user can not communicate with a satellite other than during the course of time that this satellite is "in view" of the user; this duration is generally of the order of twenty minutes. It is therefore necessary that, on the one hand, the user's antenna can follow the satellite over its trajectory and, on the other hand, the user can instantly switch communication over the next satellite, which enters his field of vision, since the satellite precedent is leaving his field of vision. The instantaneous commutation is especially necessary for interactive communications for which an interruption of the service, even if it is of short duration, is not contemplated. To solve this problem, a device for transmitting and receiving two antennas is generally envisaged, one of which is moved to follow the satellite with which the user communicates and the other is on hold and focused towards the beginning of the vision of the next satellite.

The transmitting and receiving devices and, in particular, their antennas, intended for such telecommunication systems must be particularly light and of reduced dimensions to facilitate the movement and installation on the roof of a building (particularly of an individual house) and, thus, , fix the aesthetic.

In addition, it may be advantageous to associate the two transmitting and receiving devices in a common focusing lens. In that case, these two devices must coexist in a limited space, which reinforces the need for light saturation and lightweight of these devices.

Under these conditions, it is hardly contemplated to mention a high rejection waveguide / duplicator configuration that is heavy and saturating. It is then used to a more compact technology of which the most common is called "micro tape". But with this technology, the known solutions to the problem of isolation between the emission and reception drags important losses that degrade the quality of connection or force the transmission of the antenna.

For example, JP 10 022728 discloses a circular polarization antenna resorting to such technology and used for a single type of transmission, namely, transmission or reception and then for a single frequency band. Accordingly, an emitting and receiving device should comprise two antennas of this type with a hybrid coupler since the same type of polarization is used for the two frequency bands.

JP 06 140835 concerns a circular polarization antenna containing a patch for emission and a patch for reception. Accordingly, an access by frequency band is provided, which means an oversizing of the antenna.

The invention provides a particularly compact transmitting and receiving device which allows simultaneous emission and reception and ensures a minimized disturbance of the signal received by the emitted signal, a slight loss emission and a reception with a slight interference factor, is say with a signal to high interference ratio.

The transmission and reception device according to the invention is characterized in that the emission and reception signals have circular polarizations of inverse directions and because the antenna of the device contains a radiating element with two accesses, or orthogonal lines, one for emission and another for reception.

Following a first embodiment, the radiant element is a compact element that contains an aapilamiento of: .a short-circuit cavity; an intermediate cavity; .A cavity of adaptation; .a rectangular section of polarizing waveguide, The three short-circuit, intermediate and adaptation cavities that allow regulating access adaptation in relation to the desired frequency bands, an access that is arranged between the short-circuit cavity and the intermediate cavity, the other access that is arranged between the intermediate cavity and the adaptation cavity.

Following a second embodiment, the radiating element contains at least one planar tablet.

To obtain circular polarizations in opposite directions, the plane radiating element must not have a circular shape, but a deformed shape, for example according to semi-bevels.

The emission and reception signals that are in orthogonal polarizations already ensure a certain isolation between emission and reception, of the order of 20 dB.

In addition, the retained technology, with a planar element of non-circular shape and perpendicular access, minimizes the interference and the weight of the antenna. In particular, the number of elements of the device is minimized since it is not necessary to foresee either a circulator, which would prevent the use of two reverse polarizations, or a 90 ° hybrid coupler that transforms orthogonal linear polarizations into circular polarizations of inverse directions.

The minimization of the number of components contributes to the minimization of the cost of the device.

Given that the emission and reception frequency bands are different, the radiating element must be able to operate on a relatively wide band comprising the two useful bands. To optimize this broad-band operation, in one embodiment, two superimposed planar radiating elements of different dimensions are provided, one resonant over a frequency corresponding to the emission band, and another resonant according to a frequency that is in the reception band.

The two radiating elements are, for example, arranged in a cavity, which optimizes the directivity of the radiating element. In effect, the cavity prevents back and side radiation and limits the radiation in a useful cone, directed towards the source of emission and reception with which the device communicates, particularly a satellite in trajectory, as explained above.

When two superimposed radiating elements are provided, it is possible either to foresee the accesses on one of these elements, preferably the one of inferior position, or to foresee accesses without contact with any of the two elements. In the latter case, the accesses are preferably below the lower radiant element.

Other characteristics and advantages of the invention will appear with the description of certain of these embodiments, this being done referring to the drawings annexed to the present on which: Figure 1 is a diagram showing the use of an emission and reception device according to the invention in a satellite telecommunication system in the path, Figure 2 is a diagram of an antenna comprising two transmitting and receiving devices according to the invention, this antenna also being used in a satellite telecommunication system, Figure 3 is a diagram of a part of the transmission and reception device according to the invention, Figures 3a and 3b are diagrams analogous to that of Figure 3, but for variants corresponding to the previous stage of the technique, Figure 4 is a diagram in the top of an emission and reception device according to the invention, Figure 5 is a diagram of the transmission and reception circuits of the device according to the invention, Figure 6 represents an embodiment of reception circuits, and Figure 7 is an open and detailed perspective view of another embodiment of the compact radiant element.

In the telecommunication system represented on FIG. 1, a set of satellites 10, 12 circulates on an orbit 14 at an altitude of approximately 1000 to 1500 km above the surface 16 of the earth. Each satellite contains means of emission and reception to relieve a communication between terrestrial users and access stations to specific services, such as data banks. A user terminal 18 which establishes an interactive communication with another user or a terrestrial station (not shown) by means of satellite 12 is thus represented on FIG. 1. The interactive character of communication is symbolized by a double arrow 20 on the path of the electromagnetic waves between the antenna 22 of the satellite 12 and the antenna 24 of the subscriber 18.

The antenna 24 is, for example, arranged on the roof of an individual house. It contains a focusing surface 26, for example spherical, as depicted on FIG. 2, and two radiating elements 28 and 30 movable on the focal surface 26 of the antenna 24.

The radiating element 28 is programmed to follow the satellite 12 with which the user is in view, while the radiating element 30 is in a waiting position. The latter remains pointed towards the zone of appearance of the next satellite. In effect, when the satellite 12 leaves the field of view of the antenna and that the next satellite enters this field of vision, the radiating element 30 replaces the element 28 used to effect the communication. The switching of the element 28 to the element 30 can be carried out instantaneously.

In the example shown in FIG. 1, the user 18 is provided with a device 32 that allows the satellites to be monitored, the emission and reception of the signals controlled and, possibly, deciphering these signals. This control device is connected to a micro-computer 34 or analog memory organ in which information related to the positions of the satellites are recorded, so that at any moment the motors that ensure the movement of the satellites can be controlled. radiant elements 28 and 30 so that they are pointed accurately towards the satellites. > If a microcomputer is used, it can also be used to receive or broadcast programs.

In this multimedia application example, it is also envisaged to connect, by means of a connector or distributor 36, a telephone or telecopy line 38 and a receiver 40 for television or radio broadcasts.

FIG. 2 shows a more detailed example of an antenna 24 with radiating elements 28 and 30. In this embodiment, a fixed lens 42 is provided, which allows to receive a hyperfrequency beam over a solid angle of sufficient value to collect the signals of satellites in trajectory in the user's vision area. This lens focuses the received rays on a spherical surface 0 on which the radiating elements 28 and 30 move. This lens 42 is supported by two uprights of which only one, reference 44, is visible on Figure 2.

The radiating elements 28 and 30 are movable on the focusing spherical surface 26. For this purpose, two motors and two arms are provided for each of these elements. For simplicity, only the motors and arms of the radiating element will be described 28.

To displace the radiating element 28, a first motor 46 integral with a lower support 48 is provided and whose shaft makes it possible to rotate the arm at the end of which is the second motor 52 which itself carries a forearm 54 at the end of which there is a radiant element 28. To ensure the displacement of the radiating element 28, the motors 46 and 52 are controlled by information provided by the microcomputer 34 'or the like.

To each radiating element 28, 30 there is associated an emission circuit and a reception circuit that will be described later in relation to figure 5.

The terminals 18 that are apparatuses of great diffusion, it is essential that they are of slight saturation, of light weight and of a minimized cost. The need for a slight saturation and a light weight is reinforced by the fact that the emission and reception devices are mobile and are associated in a small volume, that of the antenna 24.

This minimization of saturation, weight and price should be compatible with high performances needed by, particularly the high flow of information and the simultaneity of the emission and reception. From this point of view, the isolation between the emission and reception signals presents a difficult problem to solve, especially in the context mentioned above, of slight saturation and of a slight price.

In the example, the reception band Rx is from 11.7 to 12.45 GHz (it can be extended up to 12.55 GHz), while the emission band Tx is from 14 to 14.3 Ghz. The emission power is a few watts, on the order of 2 to 3.

The radiant element according to the invention is of the compact type and has, for the emission and reception, substantially orthogonal access, the phase shift of the emission and reception signals and the shape of the radiating element being such that the emission and reception, whose frequencies are different, are circularly polarized in inverse directions.

Following a first embodiment (Figure 7), the radiant element contains a stack of the following elements: a short-circuit cavity 220; an intermediate cavity 221; .an adaptation cavity 222; .A rectangular section of waveguide 'polarizing 223.

The three short-circuit, intremediay and adaptation cavities allow regulating the adaptation of the accesses in relation to the desired frequency bands.

For this purpose, an access 224 is arranged between the short-circuit cavity and the intermediate cavity, the other access 225 that is arranged between the intermediate cavity and the adaptation cavity.

The operation can be described schematically by the following points: The mono-band or bi- band aspects are administered by the three short-circuit, intermediate and adaptation cavities.

The radioactive interface constituted by the rectangular section of polarizing waveguide 223 makes it possible to propagate two orthogonal TE01 and TE10 modalities in the desired bands. From the fact of the rectangular section, the group speed of the modalities TE01 and TE10 differ slightly, which allows to create a phase shift between these two modalities. The phase quadrature between the two modalities is obtained when the conditions in the limits of the rectangular section 223 and its length (approximately? G / 4) are adequate: the antenna generates the circular polarization.

The orthogonality of the accesses -224 and 225 allows an isolation between the access and the superimposed excitation of two pairs of modalities TE01 and TE10 with opposite quadrature conditions for each pair allowing a double circular polarization to be obtained.

The cavity formed by the rectangular section -223 and the access part on the one hand and the radiative part on the other hand allows the obtaining of a phase quadrature condition of modalities TEQ1 and TE10 on large band amplitudes.

The stack containing the short-circuit cavity 220, the intermediate cavity 221 and the adaptation cavity 222 constitutes a cavity which is shown to be circular on FIG. 7. This cavity can also be substantially square in shape. Their sides are then substantially perpendicular to the excitation lines 224a and 225a constituting the accesses respectively 224 and 225 and consequently inclined at approximately 45 ° in relation to the rectangular section 223.

With respect to Figure 7, the technology represented by the accesses 224 and 225 corresponds to a triplaca solution, but other solutions can be selected depending on the application, such as for example: .a co-axial solution; .a micro-band solution inverted or not in relation to the Z axis of the antenna signal R; .for the lower access 224, a grooved or wave-guided coupling; .a waveguide solution for applications beyond the Ku band; . a mixed solution such that each access 224, 225 is made following one of the preceding solutions.

In order to ensure electrical contact between the different cavities presented in the alignment of the Z axis, the engravings may be double-sided with metallic holes. This last solution is justified particularly for applications in bands of frequencies higher than 6 GHz (band C).

Following a second embodiment, the radiating element is of planar type and comprises a pad or "patch" 60 (FIG. 3) which has the shape of a circle truncated by parallel semi-bevels 62-64. To this pad 60 are associated two accesses 66 and 68 in micro-ribbed lines that form a 90 ° angle. These two accesses 66 and 68 are excited by signals 90 ° out of phase. The access 66 corresponds to the reception and is therefore connected, in particular, to a light interference amplifier 70, while the access 68 corresponds to the emission and is thus connected, among others, to a power amplifier 72.

The excitation of lines 66 and 68 by 90 ° offset signals allows to obtain emission and reception signals that are circular polarizations in inverse directions. The orthogonal polarizations of the emission and reception signals, added to the frequency bands other than these signals, allow an isolation of the order of 20 dB between these signals. The planar technology used to realize the radiant element minimizes its cost, its saturation and its weight. In addition, the realization in two shortcuts minimizes the number of components and allows to pass hybrid coupler in wide band or circulator corresponding to the previous stage of the technique such as that represented by figure 3a (use of a circulator) and by the Figure 3b (use of a hybrid coupler).

In the known example shown on FIG. 3a, there is provided a truncated circular flat wafer 74 having an access connected to the output of the power amplifier 72? (emission circuit) by means of a circulator 76. Access 78 is also connected to the reception path, ie to a light interference amplifier 70 ?, by means of the same circulator 76.

In the example of figure 3b, there is provided a planar radiating element 80 of unbroken circular shape having two orthogonal accesses 82 and 84 connected to two terminals, respectively 86 and 88, of a hybrid coupler 90 containing two other terminals, respectively 92 and 94. the terminal 92 is connected to the input of a light interference amplifier 70_, and the terminal 94 is connected to the output of the power amplifier 72. In a manner known per se, the 90 ° hybrid coupler can transform orthogonal linear polarizations, on its terminals 92 and 94, into circular polarizations in opposite directions on its terminals 86 and 88. As well as accesses 82 and 84, the signals have polarizations Circular of inverted senses. The hybrid coupler 90 is preferably of the wide band type. For this purpose, one or several supplementary branches 96 are provided in micro-tape, also in a manner known per se.

HE. is now going to describe, in relation to Figure 4, an embodiment of a planar emission and reception device that can be used preferably with the embodiment of Figure 3.

In this example, two superposed planar tablets are provided, respectively 98 and 100. Each of these tablets has a shape corresponding to that shown in figure 3, that is to say the shape of a semi-beveled circle. However, the dimensions of these pills are different. One of them, the lower tablet 98, has dimensions corresponding to a resonance in the reception band and the upper tablet has lighter dimensions corresponding to a resonance in the emission band (the highest frequencies).

The two pads have a relative diusposition such that they have the same central axis perpendicular to their planes) and that their bevels are parallel.

The accesses 102 are arranged under the lower tablet 98. On the figure 4 a single access is visible. These accesses are in line with micro-tape or triplaca suspended. They are connected to the filtering circuits and to the amplifiers of slight interference or power by means of microtape or triplet lines. In the example, the filtering and adapting means are also in the micro-tape or triplet line.

The pellets as well as the accesses are arranged in a cylindrical cavity 110 open towards the top and having a bottom 112.

This cavity 110 limits the cone of emission and reception of the ultrafrequency waves in order that this cone is relatively narrow, directed towards the satellite 12.

The bottom of the cavity is connected to a channel 114 of axis perpendicular to the axis 116 of the cylindrical cavity 110. In this channel there is arranged a substrate 118 which contains, on the one hand, the access lines 102 and, on the other hand, filtering circuits and adaptation in micro tape or triplet lines 120. The substrate also, at the end of the channel 114 opposite the cavity 110, of the active elements 5 such as transistors 122 of amplifiers. The end part of the channel 114 that contains the transistors 122 in planar micro-tape technique is separated from the circuits 120, preferably in triple planar suspended technique, by means of a sealing wall 124.

The end of the channel 114 comprises a terminal 128 for the reception signals and a terminal 130 for the emission signals.

The upper opening 132 of the cavity 110 is closed by a protective cap 134 in plastic material such as Teflon or ABS. » In variant (not shown) the accesses are on one of the pads, for example the reference 98.

It is also possible to provide a single tablet with accesses on this pad or at a distance from the latter.

We will now describe, in relation to Figure 5, another provision that relates to filtering and amplification that minimizes interference, particularly that generated by filtering, always allowing the cost of realizing the circuits to be reduced. In addition, the losses are minimized.

The emission and the reception that are carried out simultaneously, the elimination, by filtering, of the emission frequencies in the reception circuits as well as the elimination, by filtering, of the reception frequencies, in the emission circuits must be particularly effective.

For this purpose, planar filters and an amplification and filtering in several stages are foreseen in each circuit. The attenuation, or rejection, of the filter that is closest to the radiating element has a value that is a fraction of the attenuation necessary to eliminate the frequencies to be suppressed. In one example, the total rejection rate necessary to eliminate the emission (or reception) frequencies is of the order of 50 dB and the rejection of the filter of the first (or of the last stage) is only of the order of 14 dB. This last value is calculated as a function of the compression point of the first transistor (amplifier) in reception (or of the interference factor of the last transistor, amplifier, in emission), of the power to be emitted, or of the isolation between the two ports of the source (radiant element).

The amplification provided by the last stage of amplification and preferably that which can be obtained with a transistor of very slight interference.

In this way, the interference seen by the radiating element is minimized. In fact, the interference depends above all on the interference provided by the amplification stage and the filter closest to this element. On the other hand, the interference provided to the radiating element by the furthest stages of amplification and filtering do not intervene except in an attenuated manner, since this interference is diminished in proportion to the advantage of the intermediate amplification stages that lie between the - Radiant element and the filter generator of the interference.

In addition, the planar filters of moderate rejection can be carried out easily, at a moderate cost, since the substrates used can be of a low recovery price. It is known that filtering in a planar micro-tape technique (or suspended triplaca) requires, for high rejection rates, relatively expensive aluminum substrates, since for lighter rejection rates, cheaper substrates can be used, for example. example based on PTFE, as will be seen later.

In the example shown on FIG. 5, the reception circuit comprises a first part 140 disposed between the access 142 of the chip 144 of the radiating element and an end of a cable 146. ' A second part 148 is disposed between the other end of the cable 146 and the demodulator (not shown) of the reception circuit.

The access 142 is directly connected to the input of a first filter 150 of the pass band type for the reception frequencies and the band-cut type for the emission frequencies. For emission frequencies, it has a relatively moderate rejection characteristic, 14 dB. For the reception frequency, the attenuation (or loss) is of slight value, of the order of 0.2 dB.

This first filter 150 is connected to the input of a first amplifier passage 152, to a single transistor in the example.

This amplifier 152 has an advantage of 8 dB in the example. It is noteworthy that this 8 dB advantage is not the maximum advantage that can be obtained with a transistor. But, in the example, the interference is minimized to a slight detriment of the advantage, as will be seen later in relation to Figure 6.

This first part 140 of the reception circuit also contains a second filter-amplification stage pair, namely a filter 154 whose input is connected to the output of the first amplifier 152 and a second amplifier 156 constituted, in the example, by a single transistor. The filter 154 has a rejection of 10 dB for the emission frequencies and a slight rejection, 0.2 dB, for the reception frequencies. Amplification stage 156 has an advantage of 10 dB.

In this example, the stray emission signal at the output of step 156 is less than 10 dBm.

The cable 146 - which, in the example, introduces an attenuation of 1.5 dB - is connected to the second filtering and amplification part 148 comprising a third filter pair 158 - amplifier 160. The filter 158 receives the signal provided by the cable 146 and releases a signal to the third amplifier 160. The attenuation of the filter 158 for the emission frequencies is 26.5 dB and the attenuation of the filter 158 for the emission frequencies is 26.5 dB and the attenuation for the reception frequencies of 1.8. dB. The amplification stage 160 has two transistors and its advantage is 18 dB.

At the output of step 160, a filtered complement signal is obtained from the emission parasitic signals. This output is connected, in a conventional manner, to a mixer 162 which receives a local oscillator signal at 10.75 GHz over another input. The output of the mixer 162 is connected to the reception demodulator by means of a low pass filter 166.

The attenuation of the parasitic frequencies that is effected by each of the filters is in accordance with the advantage of the associated amplifier in such a way that this attenuation is sufficient to prevent misalignment, or saturation (or compression), of the transistor ( es) of the amplifier by the parasitic emission signal. It is then necessary that each filter be arranged towards the start of the associated amplifier. By "to the beginning", it is understood here that the filter must be closer to the radiating element than the amplifier of the same pair.

The overall interference factor of the reception circuit is, essentially, that of the first filtering stage 150 and amplification 152.

The coaxial cable 146, as well as the corresponding coaxial cables 170 and 172 for the transmission circuit, form in the example, a deviation around the motors that can be wound or let loose depending on the displacement of the arm.

The second part 148 of the reception circuit (as well as the corresponding part of the transmission circuit) is, in the example, at the base of the antenna, that is to say in the vicinity of the center 48 (FIG. 2).

The first part 142 of the reception circuit is realized in technology called "hybrid without regulation", that is to say that active elements such as transistors are deposited directly on a substrate, without a case, and that the substrate has planar conductors, for example made by gravure. This embodiment allows the interference factor to be further minimized, ie to maximize the signal to interference ratio. Weight and saturation are also minimized.

On the other hand, the part of the circuit 148 located at the foot of the antenna, which is furthest away from the radiating element, can be made more conventionally in integrated technology such as the technology called "MMIC" ("Monolithic Integrated Circuit"). mincroondas ", that is, monolithic integrated circuit hyper frequencies). Indeed, as already indicated, the interference introduced in this step 148 intervenes little in the overall interference factor. Likewise, the losses of the highest rejection index filter 158 (26.5 dB in the example), which avoids compression or dealignment of the transistors of step 160, also intervene less critically than for part 140.

In part 140, the substrates are, for example, substrates RO 3006 or RO 4003 distributed by the company Rogers Corporation. They are constituted by a matrix of flexible organic matter such as PTFE (polytetrafluoroethylene) reinforced by glass microfibers and in which ceramic particles are trapped to increase the dielectric constant and then decrease the size of the circuits. This substrate is covered, on the one hand, by a layer of copper that constitutes the mass, while on the other side it is also coated with photo-etchable copper to make the circuits.

The emission circuit is analogous to the reception circuit. The emission access 180 of the chip 144 is connected to the output of a first filter 182 whose input is connected to the output of an amplification stage 184. the attenuation of the filter 182 is 14 dB for the reception and 0.2 frequencies. dB for the emission frequencies. The advantage of amplifier 184 is 8 dB.

The input of amplifier 184_ is connected to the • output of a filter 186 that receives the output signal of an amplification stage 188. The attenuation of the filter 186 is 10 dB for the reception frequencies and 0.2 dB for the emission frequencies. The advantage of the stage of amplification 188 is 8 dB.

The other part of the emission circuit is also at the foot of the antenna, in the vicinity of the support > 48 (figure 2), and contains a filter 190 connected to the cable 170 or 172 by means of a switch 1173. The filter 190 receives the output signal from an amplification stage 192 of four transistors. The attenuation of the filter 190 is 30 dB for the reception frequencies and 1.8 dB for the emission frequencies. The advantage of the amplifier 192 is 32 dB.

The input of the amplifier 192 is connected to the output of a mixer 194 by means of a filter 196. The mixer has two inputs which, in a conventional manner, are connected on the one hand to the emission modulator (m or shown), and on the other hand part, to a local oscillator of emission at 13.05 GHz.

For this emission circuit, the advantage of the stepwise division is that the last stage, directly connected to the access 180, presents slight losses from the fact of the slight rejection rate of the filr 182 and the relatively slight advantage of the step 184.

The cable 172 is connected to the emission circuits in the second radiating element (not shown). Otherwise, the part of the emitting circuit in the communicator 173, filter 190, amplifier 192, filter 196 and mixer 194 is common to the two radiating elements. On the contrary, the other parts of the circuit are individual in each radiating element.

An example of a particularly simple and efficient embodiment of the first receiving circuit part 140 is shown in FIG. 6. The first part (182, 184, 186, 188) of the emission circuit can be carried out analogously; it will not be described in detail.

An "important feature of this embodiment is that of filters 150 and 154.

It is known that these filters must have characteristics of bandpass to slight loss for the reception frequencies, and bandpass of strong attenuation for the emission frequencies.

Each of these filters comprises at least one planar conductor element, formed by an engraving which, in the example, is transverse to the current propagation engraving 200. It is thus seen that the filter 150 contains a first elongate rectangular metal engraving 202 perpendicular to the metal engraving 200, and is terminated in a classical open circuit. The filter 150 also contains a second engraving 204 or line in derivation on the line 200. This end 204 is terminated by a pseudo "short-circuit", this short-circuit that is disguised by a large capacitive piece 206. In this latter case, a connection with the mass by metallic holes.

The end 202 that is terminated in open circuit must have an extension I such that it has at its joint with the main line 200 an open circuit for the emission frequencies and a short circuit for the reception frequencies.

This extension I must be a multiple of ^ for the wavelengths I that correspond to the reception frequencies and a multiple of H for the wavelengths corresponding to the emission frequencies.

To achieve this goal, extension I is selected at an equal value of Id / 4, Id being a wavelength corresponding to a frequency f equal to the difference ft-fr between two frequencies ft and fr, ft being a frequency of the emission band and fr, a frequency of the reception band. The frequencies fa, ft fr are also selected to satisfy the following relationships:Ft = (2m + 1) fc Fr = 2mfc In these formulas, m, is a positive integer.

In this way, the length I is a multiple of for the emission frequencies and is a multiple of for the reception frequencies. Under these conditions, the element 202 constitutes a short circuit for the reception frequencies and an open circuit for the emission frequencies.

The end 204, terminated by the large capacitive piece 206 that simulates a short circuit in the joint 204-206, must have a length I 'selected such that the element constitutes a short circuit for the emission frequencies and an open circuit for reception frequencies. A length of I 'of Id / 4 will be selected, Ia corresponding to a frequency fa = ft-fr / with: ft = 2mfa / y fr = (2m-l) fd Whatever the embodiment, the desired result is obtained, namely the strong attenuation of the emission frequencies and the undisturbed transmission of the reception frequencies.

In the example for which the R-band is 11.7 to 12.45 GHz and the T-band is 14 to 14.3 GHz in the case of Cape 204 terminated by a pseudo-short circuit, the frequencies fL, ft and fa can be selected of following values. fr = 11.75 GHz ft = 14.1 GHz fr = 5f = and f- = 6 fa For the element 202 terminated in open circuit, on the contrary, frequencies fL and fa will be selected, such that fr, is an even multiple of f3 and f is an odd multiple of fj.

It is to be noted that either a filter element 202 alone can be used, without the filter element 204-206, either the filter element 204-206 alone, without the element 202, either finally as it was represented, the two filtering elements simultaneously.

The amplifier stage 152 contains a transistor 208 as well as recorded for the impedance matching and the polarization of the electrodods. The transistor 208 is, in the example, a transistor of type FHX13X of the Fujitsu brand. Its grid is connected to the line 200 by means of a rectangular engraving 210. The polarizations are applied to engravings of square shapes, 212 for the grid polarization and 214 for the drain polarization.

The stage 152 is connected to the filtering stage 154 by means of a capacitor 216 for adaptation and decoupling between the bias voltages on the graphs 212 and 214.

The source of the transistor 208 is connected to the ground by means of an inductance 220, which performs the role of a counter-reaction and consists of a ribbon or wiring or connection wire. The value of this inductance 220 is optimized in order to minimize the interference. It has been found that this minimization of interference can lead to a decrease in the advantage; but this decrease is slight and does not alter the amplification performances.

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention is that which is clear from the present description of the invention.

Having described the invention as above, it is claimed as property in the following:

Claims (16)

1. Apparatus for transmitting and receiving microwave hyper waves that contain a radiating element, which is characterized in that the radiating element has, for the emission and reception, substantially orthogonal accesses, the phase shift of the emission and reception signals and the reception of the signal. form of the radiating element that are such that the emission and reception signals, whose frequencies are different, are polarized in inverse directions.

2. Device according to claim 1, characterized in that the emission and reception signals are simultaneous.

3. Device according to claim 1 or 2, characterized in that the radiating element is a compact element that contains a stack of: .a short-circuit cavity; an intermediate cavity; .A cavity of adaptation; a rectangular section of polarizing waveguide, the three short circuit, intermediate and adaptation cavities that allow regulating the adaptation of the accesses with the desired frequency bands, an access that is arranged between the short circuit cavity and the intermediate cavity, the other access that is arranged between the adaptation cavity.

4. Device according to claim 1 or 2, characterized in that the radiating element contains at least one planar tablet.

5. Device according to claim 4, characterized in that the tablet has a circular shape with deformations.

6. Device according to claim 5, characterized in that the deformations are constituted by semi-bevels, for example parallel.

7. Device according to claim 5 or 6, characterized in that the radiating element contains superimposed tablets.

8. Device according to claim 7, characterized in that the two superposed tablets are arranged in a cavity.

9. Device according to claim 7 or 8, characterized in that the dimensions of the pads are different, one of the pads that resonates for the emission frequencies and the other paw that resonates for the reception frequencies.

10. Device according to any one of claims 7 to 9, characterized in that the accesses are at a distance from the lower tablet.

11. Device according to any one of claims 4 to 9, characterized in that the accesses are in contact with a tablet.

12. Device according to claim 8, characterized in that the cavity is extended by a channel containing planar access circuits.

13. Device according to any one of the preceding claims, characterized in that the emission access is directly connected to the output of an amplification and filtering circuit of the emission signals and in which the reception access is directly connected to the input of a filtering and amplification circuit of the received signals.

14. Device according to any one of the preceding claims, characterized in that the emission frequencies are in the band of 14 to 14.3 GHz and the reception frequencies in the band of 11.7 to 12.45 klO GHz.

15. Microwave and microwave emission and reception device for a: satellite telecommunication system on a trajectory around the earth, which is 15 characterized in that it comprises two transmission and reception devices according to any one of the preceding claims, these two emission and reception devices that are associated to a same focal surface that receives the signals coming from the satellites.

16. Device according to claim 15, characterized in that it contains motive means for each transmitting and receiving device to follow the movement of a satellite. 25