FR2908559A1 - MULTI-PORT COUPLER FOR THE POWER SUPPLY OF ONE OR MORE ANTENNAS BY SINGLE SOURCES FROM ONE TO THE OTHER, ANTENNA AND ANTENNA SYSTEM INTEGRATING THE COUPLER - Google Patents

Abstract

The invention relates to a system with one or more antennas comprising radiating elements (15), characterized in that it comprises a ring multiport coupler (1) for supplying the radiating elements by several power sources (G1, G2). The invention also extends to a ring multiport coupler allowing such a supply of the radiating elements of one or more antennas.

Description

The field of the invention is that of telecommunication antennas,

  and more particularly that of flat antennas for radio-relay systems (FH antennas). Flat antennas now tend to be preferred over satellite dishes. Flat antennas have the advantage of being equivalent surface, globally as effective as parabolic antennas. And these flat antennas are characterized by their compactness and low weight. A flat antenna comprises a network of radiating elements integrated in the dielectric substrate of the antenna. The flat antenna more specifically comprises a set of linear subarrays parallel to each other, each linear subarray consisting of a set of radiating elements. The radiating elements are typically each consisting of a conductive square surface having a corner connected to a subnetwork supply line (typically in the form of a micro-ribbon line). The power supply of the flat antenna is conventionally performed by providing the antenna with a coaxial connector, and by connecting the antenna to a waveguide via a guide-coaxial transition.

  However, the increase in the frequency used for the radio links implies the reduction of the physical dimensions of the elements of the antenna. This reduction leads to difficulties in producing the coaxial probe feed solution. In order to answer this problem, solutions of direct supply by waveguide have been proposed, for example (see in particular on this subject the French patent application of the Applicant filed on November 14, 2005 under n 0511527) by placing electromagnetic coupling by slot between a power supply source (typically a waveguide) and the supply lines of the radiating elements of the flat antenna.

An antenna of this type, however, is associated with a single radio equipment (i.e. a single transmit / receive channel). In other words, an antenna system has only one input. It would be desirable, however, to optimize the antennal system to provide antennal system sharing among a plurality of radio equipment, thereby associating multiple transmit / receive channels with one or more antennas. The invention aims to meet this need, and proposes for this purpose, and according to a first aspect, an antenna comprising radiating elements, characterized in that it comprises a ring multiport coupler for supplying the radiating elements by several power sources isolated from each other. Some preferred, but not limiting, aspects of this antenna are as follows: it comprises a substrate on which the radiating elements are arranged, and in that the ring coupler is a microstrip ring disposed on the substrate; the coupler has at least two inputs each in the form of an access port for a power source, said access ports being distributed along the circumference of the ring so that a A wave entering an access port splits into two waves rotating in opposite directions on the ring and arriving in phase opposition to the levels of the other access ports; the coupler has at least two outputs each in the form of a radiating element supply port, said power ports being distributed along the circumference of the ring so that an incoming wave in an access port splits into two waves rotating in opposite directions on the ring and arriving in phase at each power port; the antenna comprises a microstrip line connected to each output port of the coupler; In the antenna, in which the radiating elements are arranged in the form of linear sub-networks, each sub-network being connected to a sub-network supply line, a microstrip line connected to an output port of coupler serves as a subnet power line; In the antenna, in which the radiating elements are arranged in the form of linear sub-networks, each sub-network being connected to a sub-network supply line, a microstrip line connected to an output port of the sub-network; coupler is disposed transversely to a set of linear subnets for supplying each subnet supply line of said set; the substrate rests on a ground plane in which slots are made opposite each of the access ports, so as to achieve an electromagnetic coupling by slot between the ring and a power source arranged with respect to the plane of mass for exciting an access port 15 of the ring; each of the access ports of the ring comprises a coupling pad intended to collect the energy radiated through the slot by a power source; power sources are waveguides; A waveguide is a waveguide having a U-shaped section, arranged so that the ground plane serves as a wall closing the space of the waveguide; and - the power sources are microstrip lines or triplate lines.

According to a second aspect, the invention relates to an antenna system, each comprising radiating elements, characterized in that it comprises a ring multiport coupler for supplying the radiating elements of the antennas by several isolated power sources to each other. others.

According to another aspect, the invention relates to a multiport coupler for feeding one or more antennas by at least two power sources, characterized in that it consists of a microstrip ring having at least two inputs each in the form of an access port for a power source, said access ports being distributed along the circumference of the ring so that a wave entering a port The access port splits into two waves that rotate in opposite directions on the ring and arrive in phase opposition with the levels of the other access ports. Other aspects, objects and advantages of the present invention will become more apparent upon reading the following detailed description of preferred embodiments thereof, given by way of non-limiting example, and with reference to the accompanying drawings. which: Figure 1 is a diagram showing an antenna according to the invention connected via a coupler three transmission / reception chains; Figure 2 shows the frequency spectrum of a FH transmission; Figure 3 is a diagram illustrating the transmission, and reception, of several different channels on the same antenna; Figure 4 shows the resulting spectrum at an antenna of Figure 3; Figures 5 and 6 illustrate the design of a ring coupler having five inputs; Figures 7, 8 and 9 show a possible embodiment of the ring coupler microstrip technology, the ring being integrated in the antenna substrate; FIG. 10 represents a possible embodiment of the supply of the radiating elements of an antenna; Fig. 11 shows a ring coupler having microstrip access; Figures 12 and 13 are diagrams showing an antenna system according to the second aspect of the invention.

With reference to the diagram of FIG. 1, there is shown an antenna A connected via a multiport coupler 1 to three transmission / reception chains C1, C2 and C3. The coupler 1, which will be detailed in more detail later, makes it possible to develop an antenna A having several inputs (the chains C1, C2 and C3) not interfering with each other. An illustrative and nonlimiting example of application of such an antenna is that of an antenna having two transmission / reception channels, one serving for transmission / reception of the useful signal (for example a GSM signal ), and the other used to check the conditions of reception of said useful signal (tracking chain, or Cracking according to the English terminology). Another example of application is that of the transmission FH. In the field of radio links, duplex transmission is provided with a duplex deviation which depends on the frequency band. For radio-relay systems at 38 GHz, for example, the signals are transmitted with a duplex difference of about 1 GHz between transmission and reception. The frequency spectrum of such a transmission is shown diagrammatically in FIG. 2, in which the duplex deviation between the reception band and the transmission band is referred to as Ed. As shown diagrammatically in FIG. the multiport coupler 1 makes it possible to envisage the transmission of several different channels on the same antenna A1, and the reception of the different channels on the same antenna A2.

FIG. 4 shows the resulting spectrum at the antenna A1 at the output of the multiport coupler 1. It will be noted that the inputs (duplex transmissions 1, 2 and 3) of the antenna do not interfere with each other. with each other. In particular, the reception of the channels 2 and 3 takes place in the duplex deviation separating the transmission from the reception of the channel 3.

It is thus clear that the coupler makes it possible to multiply the bit rate of an FH link without adding an antenna, which proves to be particularly advantageous for meeting the needs of integration of the antennas, especially in an urban environment. According to a first aspect, the invention relates to an antenna, in particular a flat antenna, comprising radiating elements (or patch according to the English terminology). The antenna also includes a ring multiport coupler for powering the radiating elements from multiple power sources isolated from each other. The multiport coupler has at least two inputs each in the form of an access port for a power source, said access ports 10 being distributed along the circumference of the ring so that a A wave entering an access port splits into two waves rotating in opposite directions on the ring and arriving in phase opposition at the levels of the other access ports. FIGS. 5 and 6 show the design of a ring multiport coupler having 5 inputs (an input that can serve as an access port for a power source). Note that in general, a coupler according to the invention can be designed to include 2n + 1 inputs, with n an integer greater than or equal to 1. The ring 2 of Figure 5 has an electrical perimeter of 5X / 2. We consider a reference access at the level of the arrow F. A wave entering the ring 2 at the reference port F divides into two waves which turn in opposite directions on the ring 2. There exists then along the circumference of the ring different remarkable places separated by a distance of X / 4. These remarkable places .25 correspond to: - places where the two waves combine in phase (the difference of path traveled by each of the two waves is k * a ,, with k equal to 1 or 2 in the example here selected ); places where the two waves combine in phase opposition (the difference in path traveled by each of the two waves is (2p + 1) * X / 2, with p equal to 0, 1 or 2 in the example here retained); These remarkable places are denoted access O and PI for respectively: Access 0, corresponding to a place where the signals emitted by the reference access arrive in phase; PI access, corresponding to a place where the signals emitted by the reference access arrive in phase opposition (in theory they cancel each other out, in practice we find the strongly attenuated incident signal, for example of 25 dB). Thus the reference access can be considered as being isolated from the PI accesses. Similarly, if we consider a PI access it is found that it is also isolated from the reference access and other PI accesses. As illustrated in FIG. 6, it is decided to position the I / O inputs of the coupler (that is to say the access ports for a power source) on the places PI. This provides maximum isolation of the inputs relative to each other.

The coupler AA outputs (i.e., the antenna ports serving as radiator supply ports) are positioned at the locations 0 of the reference port. Note that if we consider another PI access, the output AA is also positioned at a location 0 for this other PI access. Thus, at the AA antenna port, all (at least attenuation) of the signals from each of the I / O inputs are collected. Note also that according to the principle of reciprocity, a wave coming from the antenna, and returning to the ring 2 will recombine in phase at the I / O access, and in phase opposition at the other outputs AA. This ensures the distribution of a signal from the antenna to the five I / O accesses, as well as the isolation of the different antenna accesses between them. According to a preferred embodiment, and with reference to the partial perspective view of FIGS. 7, 8 and 9, the antenna is of the flat antenna type comprising a ground plane 3, and a substrate 4 attached to the plane of mass. on which is disposed a printed circuit containing said radiating elements.

In the context of this embodiment, the coupler is in the form of a ring 2, preferably made in microstrip technology to be integrated in the printed circuit disposed on the substrate 4. FIG. 7 represents an overall view illustrating the physical structure of the multiport microstrip ring coupler. Figure 8 shows more precisely the waveguide access subsystem, while Figure 9 more closely represents the microstrip access subsystem. In the coupler of FIGS. 7, 8 and 9, two I / O access ports 1 and I / O 4 for a power source and two power supply ports AA 1 and AA 4 for radiating elements are used. In this configuration, the coupler is a quadrupole with two inputs and two outputs. As is apparent in FIGS. 7 and 8, the substrate 4 rests on a ground plane 3 in which slots 5, 6 are made opposite each of the I / O access ports 1 and I / O 2. In this way, an electromagnetic coupling is produced by slot between the ring 2 and a power source arranged with respect to the ground plane to excite an access port of the ring. Preferably, the ring 2 has, at each access port, a coupling pad 7, 8, for example circular, placed above the corresponding slot 5, 6 to collect the energy radiated through said slot by a power source. According to a possible embodiment, the power sources are waveguides. FIGS. 7, 8 thus represent the end of two waveguides G1, G4 each connected to an input of the coupler (ie to an I / O access port 1, I / O 4 for a power supply ). The waveguides may be U-shaped guides in section (for example by machining a channel in a metal body), arranged with respect to the ground plane so that the ground plane serves as a guide. wall closing the space of the waveguide.

The waveguides may also be rectangular guides, pressed against the ground plane and in each of which a slot is made to be matched with one of the slots in the ground plane.

Furthermore, it will be noted that, preferably, a waveguide G1, G2 is terminated by short-circuiting it at a distance of 2 ^ / 4 from the slot, so as to report an open circuit at the level of the slot and maximize the energy transfer from the waveguide to the microstrip line. According to another possible embodiment (not shown), the power sources are triplate lines. A triplate line may comprise a conductive line sandwiched between two triplate line ground planes, and a wave radiation slot is then formed in one of the triplate line ground planes which is pressed against the ground plane. 3 of the antenna so that one of the slits of the ground plane and the slot of the triplate line are superimposed. Alternatively, a triplate line may comprise a conductive line sandwiched between two ground planes of triplate line, the ground plane of the antenna constituting one of the plane plane of triplate line.

According to yet another possible embodiment, the power sources are access lines in microstrip technology. FIG. 11 schematically shows a ring multiport coupler with microstrip access. A microstrip line 9 serving as a power source is positioned transversely to a slot 5 in the ground plane of the antenna. The ring 2 forming the coupler is integrated with the substrate attached to the ground plane. In this way, the energy conveyed by the microstrip line 9 radiates through the slot 5 and is collected by the ring 2. It will be noted that in this embodiment, three metallization layers are used, with a lower layer containing microstrip access, an intermediate layer containing the ground plane with its slot, and the upper layer containing the coupler ring. Furthermore, it will be noted that, preferably, the microstrip line 9 is terminated at a distance from the slot, so as to yield an open circuit at the slot and to maximize the energy transfer of the guide. waves towards the microstrip line. Referring now to the outputs of the coupler (radiating element supply ports such as AA1 and AA4 in FIGS. 7 and 8), and as shown in FIG. 10, it will be noted that a microstrip line 10, 10 11 is connected to each output port of the coupler. For this purpose, as is apparent in FIG. 9, the ring may have, at a remarkable location 0, a microstrip line portion 12, 13 extending from the ring in the direction of the radius of the ring passing through this remarkable place, towards the outside of the ring to a supply port 15 for radiating elements AA4, AA1. The ports AA4, AA1 then allow, as illustrated in Figure 9, to connect a microstrip line 10, 11 to the portion 12, 13 extending from the ring. It will be recalled (see FIG. 10) that the radiating elements 15 of a flat antenna are typically arranged in the form of linear sub-networks, each sub-network being connected to a sub-network supply line 16. According to a possible embodiment, represented in FIG. 10, a microstrip line 10, 11 connected to an output port AA1, AA4, of the coupler 1 is arranged transversely to a set of linear subnetworks 25 to feed each of the lines subnetwork power of said set. In another possible embodiment (not shown), a microstrip line connected to an output port of the coupler serves as a subnetwork power line.

Furthermore, it will be noted that it is also possible to connect several antennas at the output of the coupler, in particular via the lines 10, 11 of microstrips connected to a radiating element supply port. The coupler described above can thus be used in antennas with several inputs and several outputs (MIMO antennas according to the English terminology Multiple Input, Multiple Output), by allowing the reception of several independent signals on the same layer (multiple accesses in source of power, for example several waveguide accesses) and transmission to several directions (several outputs, in particular in the form of a microstrip line, supply of radiating elements. FIG. 12, the multiport coupler 1 used in an antenna system comprising a plurality of antennas A1, A2, A3, A4, A5, each comprising radiating elements, for supplying the radiating elements of the antennas by several power sources. isolated from each other (inputs E1,..., E5) An example of application of the antenna system of FIG. 12 is shown in FIG. , and consists in using the coupler 1 as a switch in a redundant system having two inputs E1, E2 and two antennas A1, A2. Another example of application is that of adapting the radiation pattern of the antenna system according to the circumstances, for example in the context of mobile telephony to orient the beam of the antenna system where the radiation is located. , taking into account the displacement of the users within the cell covered by the antenna. It is specified for purely illustrative and non-limiting, that an application that we will do the coupling according to the invention relates to transmissions in the band of 37.21 GHz to 38.64 GHz. Furthermore, it will be understood that the invention is not limited to an antenna or an antenna system, but also extends to a multiport coupler as described above.

Claims (15)

  Antenna comprising radiating elements (15), characterized in that it comprises a ring multiport coupler (1) for supplying the radiating elements by several supply sources (G1, G4) isolated from each other.   2. Antenna according to claim 1, characterized in that it comprises a substrate (4) on which the radiating elements (15) are arranged, and in that the ring coupler is a microstrip ring (2) disposed on the substrate .   Antenna according to one of claims 1 or 2, characterized in that the coupler (1) has at least two inputs (I / O 1, I / O   4) each in the form of an access port for a power source (G1, G4), said access ports being distributed along the circumference of the ring (2) so that a wave entering an access port divides into two waves rotating in opposite directions on the ring and arriving in phase opposition to the levels of the other access ports. 4. Antenna according to claim 3, characterized in that the coupler (1) has at least two outputs (AA1, AA4) each in the form of a radiating element supply port, said power ports being distributed along the circumference of the ring so that a wave entering an access port splits into two waves rotating in opposite directions on the ring and arriving in phase at each power port.   5. Antenna according to claim 4, characterized in that it comprises a microstrip line (10, 11) connected to each output port (AA1, AA4) of the coupler. 2908559 13   Antenna according to claim 5, wherein the radiating elements (15) are arranged in the form of linear sub-networks, each sub-network being connected to a subnetwork supply line (16), characterized in that a microstrip line connected to a coupler output port serves as a subnetwork feed line.   Antenna according to claim 5, wherein the radiating elements (15) are arranged in the form of linear sub-networks, each sub-network being connected to a subnetwork supply line (16), characterized in that a microstrip line (10, 11) connected to an output port of the coupler is disposed transversely to a set of linear subnets for supplying each of the subnet supply lines of said set. 15   8. Antenna according to one of claims 2 to 7, characterized in that the substrate (4) rests on a ground plane (3) in which slots (5, 6) are made opposite each of the ports of access (I / O 1, I / O 4), so as to achieve an electromagnetic coupling by slot between the ring (2) and a power source (G1, G4) arranged with respect to the ground plane 20 (3). ) to excite an access port of the ring.   9. Antenna according to claim 8, characterized in that each of the access ports of the ring comprises a coupling pad (7, 8) for harvesting the energy radiated through the slot (5, 6) by a power source (G1, G4).   10. Antenna according to one of claims 1 to 9, characterized in that the power sources are waveguides (G1, G4). 30   Antenna according to claim 10 when taken in combination with one of claims 8 or 9, characterized in that a waveguide is a waveguide having a U-shaped section, arranged in such a manner that the ground plane serves as a wall closing the space of the waveguide.   12. Antenna according to one of claims 1 to 9, characterized in that the power sources are microstrip lines (9) or triplic lines.   13. Antenna system comprising a plurality of antennas (A1, .., A5), each comprising radiating elements, characterized in that it comprises: a multiport ring coupler (1) for supplying the radiating elements of the antennas by several power sources (El,   ., E5) isolated from each other ... CLFM: 14. Multiport coupler (1) for feeding one or more antennas 15 by at least two power sources, characterized in that it consists of a microstrip ring (2) having at least two inputs each in the form of an access port for a power source, said access ports being distributed along the circumference of the ring so that a wave entering an access port is divided into two waves 20 rotating in opposite directions on the ring and arriving in phase opposition to the levels of the other access ports.   15. Coupler according to the preceding claim, characterized in that each of the access ports comprises a coupling pad (5, 6) for harvesting the energy radiated through a slot by a power source.