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    • 专利摘要:
    Radiant cell for multibeam antenna. The present invention relates to a radiant cell for a multibeam antenna comprising four radiating elements intertwined with each other and with longitudinal axes in parallel, so that the radiant cell has a square cross section and where each of the four radiating elements is arranged rotated 90º with respect to its longitudinal axis and its two adjacent radiating elements, where each of the radiating elements comprises: a port; a first section of waveguide connected to the port; a first waveguide resonator with double ridge connected to the port; a second waveguide section with square cross section; a second waveguide resonator with double ridge; a third waveguide section with square cross section; and an opening of radiation; where the radiant element is configured to operate signals with a certain frequency band and a certain polarization. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2647279A1
    申请号:ES201730838
    申请日:2017-06-26
    公开日:2017-12-20
    发明作者:Piero Angeletti；Mariano BAQUERO ESCUDERO；Vicente Enrique BORIA ESBERT；Marco Guglielmi；Giovanni Toso
    申请人:Universidad Politecnica de Valencia；
    IPC主号:
    专利说明:

    Radiant cell for multi-beam antenna
    Technical Field of the Invention
    The present invention relates to the technical field of satellite communications and more specifically to the radiant cells used in multi-beam antennas, with architectures designed for the reuse of frequencies and polarizations that provide the necessary coverage.
    Background of the invention
    Communications satellites require multi-beam antennas to be able to provide bi-directional broadband communications. The multiple high gain beams with overlap, adopting both frequency and polarization reuse, allow to offer the necessary coverage required.
    Typically, a configuration of 4 interlocking beams is chosen. In order to generate multiple high gain beams, electrically large antenna reflectors are commonly used. In particular, most operational multi-beam antennas adopt a single-beam single-feed architecture (SFSB) with adjacent beams generated by reflectors fed by a cluster of speakers.
    Therefore, today the use of a standard configuration with four reflectors is usually used for a typical European coverage, as illustrated in Figure 1, where each horn provides a specific beam. The required beam dimensions will determine the physical size of the reflector and, consequently, also that of the speakers. Therefore, in order to provide contiguous coverage on the Earth's surface, the beams must be placed in separate groups, since the dimensions of the feeders do not allow them to be placed as a single group (cluster) if only one reflector is used.
    The state of the art offers some solutions to generate this type of multi-beam coverage using a single opening. For example, the concept of "reflector fed by focal grouping" (Focal Array Fed Reflector) based on the use of superimposed beams in the focal plane of the reflector, according to which said superposition is performed by connecting individual feeds using a network of beam shaping This type of antenna allows the generation of different beams with a single opening, however, the structure is quite complex at the level of the focus of the cluster.
    An alternative approach is based on the use of a single opening and consists of the superposition or overlap of the adjacent feeds in a completely radiated way, that is, without the need of any very bulky beam shaping network. It has recently been shown that this form of radiation overlap can be obtained using EBG (acronym for Electromagnetic Band Gap) or Fabry-Perot resonators in front of the array.
    However, as explained above, the solutions so far known by the state of the art for applications present great difficulties of implementation, so with long-term perspectives, alternative solutions based on a simpler opening are needed.
    Summary of the invention
    The present invention solves the aforementioned problems by offering a radiant system composed of several groups of basic cells, formed in turn by interlocking radiators based on cutting guides that allow contiguous point beams to be generated using a single main opening. For this purpose, in a first aspect of the present invention, a radiating cell is presented for a multi-beam antenna comprising four radiating elements interwoven with each other and with their longitudinal axes in parallel, so that the radiating cell has a square cross-section and where each of the four radiating elements is arranged rotated 90 ° with respect to its longitudinal axis in relation to its two adjacent radiating elements, where each of the radiating elements comprises:
    - a port, arranged at a free end of the radiant element, configured to
    receive an input signal;
    - a first waveguide section that connects the port to a first resonator;
    - a first waveguide resonator with double ridge, arranged next to the first waveguide section connected to the port;
    - a second waveguide section with square cross-section, next arranged to the first waveguide resonator with double ridge;
    - a second waveguide resonator with double ridge, arranged next to the second waveguide section of square cross section;
    - a third waveguide section with square cross-section, arranged between the second waveguide resonator with double ridge and a radiation aperture;
    where the radiating element is configured to operate signals with a certain frequency band and a certain polarization.
    According to one of the embodiments of the invention, the four radiating elements are configured to operate signals of four different colors, one color for each radiating element, where each color is formed by the combination of a selected frequency between two different frequencies and one polarization selected between two different polarizations, where said signals are orthogonal in frequency and in polarization response.
    Optionally, the first waveguide section of the radiating elements of the radiating cell is selected from a coaxial waveguide with square cross section and a double ridge waveguide.
    It is contemplated to use, in a particular embodiment of the invention, a single radiating cell as a basic building block of a four-color horn.
    Another aspect of the present invention relates to a system comprising a first plurality of radiating cells, such as those described above, arranged in a grid structure, where the arrangement comprises a single radiation aperture equal to the sum of the radiation apertures. of the radiating elements of the radiating cells of the arrangement.
    A signal distribution network connected to the grid structure is also contemplated, where said distribution network is configured to provide an input signal with a certain color to the port of the corresponding radiating element.
    Optionally, according to one of the embodiments of the invention in which the grid structure comprises a plurality of radiating cell clusters, it is contemplated that each of the clusters have interconnections between the radiating elements operating with the same color of the radiating cells of the grouping, so that each grouping forms a beam associated with a color, with an offset phase center U2 with respect to the phase center of the grouping of adjacent homologous radiating cells, where L is the dimension of the grouping.
    Optionally, according to one of the embodiments of the invention in which the grid structure comprises a plurality of radiating cell clusters, it is contemplated that each of the clusters have interconnections between the radiating elements operating with the same color of the radiating cells of the grouping, so that each grouping forms a beam associated with a color, with an offset phase center with respect to the phase center of the grouping of adjacent homologous radiating cells, so that the phase centers are arranged according to a triangular structure
    One of the embodiments of the invention further comprises a single parabolic reflector element configured to reflect the beams formed by the radiating cell clusters. Advantageously, the present invention is capable of replacing a conventional system based on 3 or 4 openings, which translates into a significant reduction in the number of satellite dishes.
    The present invention contemplates that, according to one of its embodiments, one or more radiating cells of the plurality of radiating cells arranged in the grid structure has a degree of reuse equal to four, where the degree of reuse of a radiating cell is associated with the number of beams of those participating in its conformation.
    A particular embodiment of the present invention contemplates a second plurality of radiant cells identical to the first plurality, arranged consecutively to the first plurality in a parallel plane, which further comprises a plurality of phase shifters that interconnect each radiating element of the radiating cells of the first plurality of radiating cells with a homologous radiating element of the second plurality of radiating cells. Thus, the functionality of the above concepts can be extended to a corresponding practical application with a multi-beam architecture in which a standard power cluster illuminates a transmission cluster formed by radiating cells of those described above. Advantageously, the phase shift introduced by the phase shifters is such that it allows converting the received wavefront into a new flat wavefront with a different beam pointing for each color. In this way, the radiation direction is independent for each of the four beam colors, and the antenna is capable of generating all the necessary beams with a single aperture.
    A particular embodiment of the present invention contemplates a plurality of phase shifters, where each phase shifter of the plurality of phase shifters is connected at one end to a radiating element of a radiating cell of the first plurality of radiating cells and at the opposite end is connected to a short circuit. Thus, the functionality of the above concepts can be extended to a corresponding practical application with a multi-beam architecture in which a standard power cluster illuminates a reflection cluster formed by radiating cells of those described above. Advantageously, the phase shift introduced by the phase shifters is that necessary to convert the received wavefront to another flat wavefront with a different beam pointing for each different color. Also in this case the radiation direction is independent for each of the four colors, and the antenna is capable of generating all beams with a single aperture.
    Optionally and according to one of the embodiments of the invention, it is contemplated that the radiating cells of the first plurality of radiating cells comprise at least one 90 ° hybrid coupler configured to operate with circular polarizations.
    According to one of the implementation possibilities of the present invention, the system is configured to operate with a first plurality of transmission frequency bands and a second plurality of reception frequency bands.
    The present invention contemplates in one of its possible embodiments, a plurality of printed circuits, where each of the printed circuits is implemented with a functionality identical to that of a radiating cell.
    For a more complete understanding of these and other aspects of the invention, their objects and advantages, reference may be made to the following specification and the accompanying drawings.
    Description of the drawings
    To complete the description that is being made, and in order to contribute to a better understanding of the features of the invention, according to an example of one of the embodiments thereof, accompanying said description as an integral part thereof. , some drawings are included in which, by way of illustration and not in form
    restrictive, the following is represented: Figure 1.- shows a scheme of a single feed per beam according to the state of the art. Figure 2.- shows a diagram of a radiant cell according to the present invention. Figure 3.- shows a diagram of a radiating element of a radiating cell. Figure 4.- shows a simulation of an infinite group of radiators. Figure 5.- shows a first embodiment of a multi-beam antenna based on a single reflector fed by a grouping of elements according to the present invention.
    Figures 6a and 6b.- show a second embodiment of a multi-beam antenna basedin an element transmission cluster according to the present invention.Figures 7a and 7b.-show a third embodiment of a multi-beam antenna basedin a reflection group of elements according to the present invention.Figures 8a and 8b.- show a first example design of the grouping offeeding.Figure 9.- shows the interconnections of the beamforming sub-array network,according to the design of figure 8.Figure 10.- shows the degree of reuse of the elementary cells, according to thedesign of figure 8.Figures 11a-11d.-show the beam shaping networks for beams offrequency and polarization homologs, according to the design of figure 8.Figures 12a-12d.-show the sub-arrays corresponding to figures 11a-11d.Figures 13a and 13b.-show a second example design of thefeed grouping.
    Figure 14.- shows the interconnections of the beamforming sub-array network,according to the design of figure 13.Figure 15.- shows the degree of reuse of the elementary cells, according to thedesign of figure 13.Figures 16a-16d.-show the beam shaping networks for beams offrequency and polarization homologs, according to the design of figure 13.Figures 17a-17d.-show the sub-arrays corresponding to figures 16a-16d.Figures 18a and 18b.- show a third example design of the groupingof feeding.Figure 19.- shows the interconnections of the beamforming sub-array network,according to the design of figure 18.
    Figure 20.- shows the degree of reuse of the elementary cells, according to the
    design of figure 18.
    Figures 21a-21d.-show the beam shaping networks for beams of
    frequency and polarization homologs, according to the design of figure 18.
    Figures 22a-22d.-show the sub-arrays corresponding to figures 21a-21d.
    Figure 23.- shows two embodiments of the present invention applied to horns
    in rectangular and circular guide.
    Figure 24.- shows an embodiment of a radiant cell of the present invention
    implemented in multilayer peB circuits.
    Detailed description of the invention
    What is defined in this detailed description is provided to help a thorough understanding of the invention. Accordingly, people moderately skilled in the art will recognize that variations, changes and modifications of the embodiments described herein are possible without departing from the scope of the invention. In addition, the description of functions and elements well known in the state of the art is omitted for clarity and conciseness.
    Of course, the embodiments of the invention can be implemented in a wide variety of architectural platforms, protocols, devices and systems, so the specific designs and implementations presented in this document are provided solely for purposes of illustration and understanding, and never to limit aspects of the invention.
    The present invention discloses a radiating cell (21) for a multi-beam antenna, which acts as a radiating element and which in turn is composed of several interlocking radiators (22) based on cutting guides, as can be seen in Figure 2. Specifically, in one of the embodiments of the invention, this array includes four elements associated with two different polarizations and two different frequencies, which are physically interwoven but behave as completely overlapping elements from an electromagnetic radiation point of view. Thus, said radiating cell can be advantageously used as a radiating elementary cell in different antenna architectures, allowing contiguous point beams to be generated using a single main opening.
    A preferred configuration of a single cell, consisting of 4 openings (elements), as well as the detailed geometric configuration of one of the four radiating elements, respectively, are detailed in Figure 3. Thus, a radiating element of the unit cell shown in the embodiment of Figure 3, comprises two waveguide resonators with double ridge, and several uniform waveguide sections. Specifically, according to one of the embodiments, a radiator element comprises a port (31) with coaxial excitation located at one end, through which the input signal is fed to the radiating element; a coaxial waveguide section (32) of square cross section that connects the input port to the first resonator; a uniform waveguide section in double ridge that acts as the first resonator (33); a square waveguide section that acts as a coupling element (34) between the first and the second resonator; a second section of coaxial waveguide of square cross-section acting as a second resonator (35); and a square waveguide section that acts as a coupling element
    (36) between the second resonator and the radiation opening (free space).
    To demonstrate that the innovative element described in this document (elementary radiant cell) can adequately produce a uniform field in the opening of the elementary cell from each of the 4 separate beam ports, commercial software (FEST3D) capable of Simulate the electromagnetic behavior of a set of radiators as described above and shown in Figure 2. To simplify the calculations, the size of the group (or cluster) is assumed to be infinite, which is a very common assumption in Engineering of antennas for the analysis of large clusters (arrays), as in this case, obtaining an acceptable accuracy if we have to analyze in detail the behavior of a single radiating element.
    Figure 4 shows the results obtained with these simulations if the radiated power is observed perpendicular to the grouping or "array" (broadside direction) of an infinite group of radiators as shown in Figure 2. In the broadside direction only Consider vertical polarization, based on the configuration of the unit cell (21).
    In the reflection of the input ports (41-44) of each constituent element of the unit cell (22), it is observed that the structure of the present invention behaves like two two-pole filters, whose responses are centered around the center frequencies of each color (19.75 GHz in (4 1-42) and 20.15 GHz in (43-44) for this example). For elements whose pass band is centered on the first frequency, the power radiated by the vertical element (22) is maximum (45) around the first frequency and forms a beam 1, while the power radiated by the arranged element horizontally (22) is minimal (46). Similarly, for elements whose pass band is centered on the second frequency, the power radiated by the vertical element (22) is maximum (48) around the second frequency and forms a beam 2, while the radiated power for the horizontally arranged element (22) it is minimal (47). In the case of considering the horizontal polarization in the broadside direction, the power radiated by the horizontally arranged elements would be maximum within the pass band of each element (thus forming beams 3 and 4), and the power radiated by the you do 1 and 2 would be minimal.
    From the results shown in Figure 4 it can also be deduced that the power radiated by the beams centered at a frequency is relatively low within the other band of the other beams, guaranteeing a low mutual coupling between beams. For this, a suitable filter order (2 in the example shown) must be chosen for the frequency separation of the different passbands. In addition, in Figure 4 it is observed that the power rejection at frequencies outside the pass band is relatively high (for example, (41) in the rejection band of (43 ', which minimizes the power coupling between colors orthogonal with the same polarization and different pass band.
    Therefore, the described elementary cell essentially behaves as four integrated components, more specifically as an antenna, an orthodontic transducer (OMT) and two diplexers (that is, one for each polarization). The function of the diplexers is to provide the necessary frequency isolation between the beams generated in the same polarization. Thus, it is demonstrated that the radiating cell presented in Figure 2 can generate four independent and orthogonal beams, as a combination of two pass bands centered at different frequencies and two orthogonal polarizations (linear in the example shown, but that could be circular to right and left).
    Although interleaved array clusters ("interleaved array" in English) composed of different types of elements are already known in this field, usually the basic radiation elements in the leading-edge technology of interlaced clusters, have dimensions of at least half wavelength and have an equivalent aperture close to that of the physical area they occupy.
    In contrast, the present invention proposes a radiating cell grouping in which the adjacent radiating elements, based on cutting guides, have dimensions of the order of a quarter of a wavelength, being physically interwoven (i.e., each of them occupies a portion of the cell) but they have an antenna aperture equivalent theoretically equal to four times their physical opening: that is, the physical opening is reused four times. Therefore, in practice the four elements are completely overlapped in terms of the electromagnetic field, and the electromagnetic field produced in the opening is composed of the superposition of four different signals (which are characterized by having two different polarizations and two different operating frequencies. ), which explains why even though the four elements are physically intertwined, they behave as completely overlapping elements at the electromagnetic level. This property does not violate any physical law, since the four signals associated with the four "colors" can share and completely reuse the same opening by being, by design, orthogonal in frequency and in polarization response.
    According to different embodiments of the present invention, the radiating cell described above can be applied to different antenna architectures, in particular three different types of possible multi-beam architectures (or practical applications) are highlighted below:
    Figure 5 refers to the first of these embodiments or applications of the present invention, where a multi-beam antenna based on a single reflector (51) or lens (constituted by a single or multiple apertures) and fed by one or more is represented power clusters (52) of cutting radiation elements that illuminate the reflector or lens of the system. In this antenna the power grouping (or sub-array) is composed of radiating elements of the basic radiating cell, the same ones that make up the interlocking radiating elements based on cutting guide.
    Figures 6a and 6b refer to the second of these embodiments or applications of the present invention, where a multi-beam antenna (61) is represented based on one or more transmission groups (62) ("transmitarray 'in English) of elements of radiation to the cut and an element of the basic cell (63) of the transmission group or 'transmitarray'. The multi-beam antenna 61 comprises one or more feed groups
    (64) illuminating the clusters in transmission (62) or "transmitarrays" composed of radiating elements of the basic cell (63), which make up the interlocking elements radiating to the cut.
    Figures 7a and 7b refer to the third of these embodiments or applications of the present invention, where a multi-beam antenna (71) is represented based on one or more reflection groups (72) ("reflectarray" in English) of elements of radiation to the cut and an element of the basic cell (73) of said group of reflection or "reflectarray". The multi-beam antenna 71 comprises one or more feed groups (74) illuminating the reflection or "reflector, /" groups composed of radiating elements of the basic cell (73), which make up the interlocking radiating elements based on guides to the cut.
    Next, the 3 embodiments presented above in Figures 5, 6 and 7 for a transmission operation are detailed in more detail, although the same concept can be extended to the operation in reception or to a hybrid operation in transmission reception. Similarly, the present invention is detailed for four "colors" of frequency reuse (two polarizations and two frequencies), but it can also be extended to different frequency reuse schemes.
    First embodiment This first embodiment, or application of the present invention, comprises a multi-beam antenna based on a reflector or lens system (consisting of a single or multiple apertures) and one or more power groups that illuminate the reflector or lens system. In this antenna, the supply array (sub-array) is composed of radiating elements based on cutting guides, such as those described above for the basic radiating cell.
    When considering a power sub-array illuminating a reflector system or lens, its cut-off elements must be characterized by the same phase so that they produce beams in the orthogonal direction to the radiation grouping (term known as "broadside direction" in English terminology). Of course the sub-arrays have different phase centers with respect to the focal point of the reflector or lens system, and this different location of the phase centers is what allows the automatic generation of a re-orientation or pointing direction (effect " squint ") in the beam reflected by the reflector system or lens.
    The first problem that the designer needs to address is the identification of an adequate number of cells (shape and dimensions of the sub-array / grouping) capable of illuminating the reflector antenna effectively, that is to say with a typical lighting efficiency and losses due to limited overflow (or spill-over), and at the same time being able to handle the typical power values associated with each beam at the primary power level. The diameter of a sub-array / cluster that generates a beam, is indicated with L, and can typically vary between 2-3 wavelengths (evaluated at the center frequency) up to 6-7 wavelengths. This value depends mainly on the type of optics selected (that is, the diameter and focal length of the reflector or lens).
    The second problem that the designer needs to solve is the synthesis of the different shaping networks of identical beams (one per beam, that is, one per "color"), so that the distance between the shaping networks of adjacent beams is approximately equal to U2. This means that adjacent beams are generated by sub-arrays Groups with overlapping openings.
    Figures 8a, 8b represent a first model example of the feed array / array (80), where a shape of the square sub-array (81) formed by 2x2 elementary cells (82) is selected. Therefore, each sub-array is composed of 4 contiguous elementary cells, arranged in a square grid-shaped structure. Each sub-array / grouping input is distributed, through a distribution network, to the inputs of the homologous elementary cells (that is, to the radiating elements (83) identified by operating at the same frequency and with the same polarization , or what is the same, identified by operating with the same color) that constitute each subarray / grouping and produce the corresponding beam (84).
    Figure 9 shows the inter-array sub-array of the beam-forming network of the homologous ports of the elementary cells, as well as the radiating elements used for cutting. Figure 10 shows the degree of reuse of the elementary cells.
    Figures 11a-11d show the beam shaping networks for homologous frequency and polarization beams (the same color) and in the series figures 12a-12d the corresponding homologous sub-arrays are shown. The 4 contiguous elements that make up an elementary cell are completely overlapping, and the corresponding 4 sub-arrays that affect the same elementary cell are also completely overlapping and translated U2. In this way, a power grouping / array can be designed whose radiators (sub-array of the same color) having a dimension L and a distance between phase centers equal to U2.
    The level of sub-array overlap, sub-array size and sub-array phase centers can be selected in several ways taking into account different performance optimization objectives.
    5 Figures 13a, 13b represent a second exemplary design of the feed grouping (130), a square sub-array form (131) consisting of 3x3 elementary cells (132) is selected. Each sub-array is composed of 9 contiguous elementary cells, arranged in a square grid-shaped structure. And each sub-array / grouping input is distributed through a network of input shaping
    10 homologs of the elementary cells (ie, to the radiating elements (133) identified by the same frequency and the same polarization) that constitute each subarray / grouping and produce the corresponding beam (134). the elementary cells that constitute the feeding group, and the phase centers of the beams are arranged in the form of a triangular grid (Iattice).
    Figure 14 shows the inter-array sub-array of the beam shaping network of the homologous ports (same color) of the elementary cells. Thus, the radiating elements can also be identified when cutting and the degree of reuse of the elementary cells used, which is explicitly detailed in Figure 15.
    Figures 16a-16d show the beam shaping networks for homologous frequency and polarization beams (the same color) and the corresponding homologous sub-arrays are shown in the series of Figures 17a-17d.
    25 Figures 18a, 18b represent a third model example of the feed array / array (180). The grid layout selected for the elementary cells constitutes an additional degree of freedom in the design, as in this third design example, where the elementary cell (182) remains square, but the grid layout chosen is triangular and the subarrays ( 181) consist of 4 elementary cells (182)
    30 rhomboid. Thus, the elementary cells that constitute the feeding group and the phase centers of the beams are arranged in a triangular grid arrangement.
    Figure 19 shows the inter-array sub-array of the beam shaping network of the homologous ports (same color) of the elementary cells. They can also
    35 observe the radiating elements at the cut (183) and the degree of reuse of the elementary cells used, which is more explicitly detailed in Figure 20.
    Figures 21 a-21 d show the beam shaping networks for frequency beams and homologous polarization (iso-color), and the corresponding homologous subarrays are shown in the series of Figures 22a-22d.
    The architecture of the power supply arrays / arrays of this first application, consisting of cutting elements, together with a reflector or lens system with a single main aperture, represents an innovative multi-beam antenna system capable of replacing a conventional antenna system based on 3 or 4 main openings. In practice, this translates into significant savings in terms of parabolic antennas, which in turn guarantees a much simpler accommodation on the satellite, maintaining similar complexity in terms of clustering / power array. However, these networks are perfectly periodic and regular.
    Therefore, one of the main innovations of the present invention relates to the radiating elementary cell described herein, consisting of cut-off elements based on double-ridge waveguides. In addition, the length of the elementary radiant element is significantly shorter than the length of the speakers used in the standard configurations of the state of the art, such as that shown in Figure 1.
    Second Embodiment This second embodiment, or application of the present invention, comprises a multi-beam antenna based on one or more feed clusters that illuminate one or more transmission clusters -transmitarrays-composed of radiating elements, the same that make up the interlocking elements radiating to the cut.
    In the transmission configuration, as can be seen in Figures 6a and 6b, two identical configurations (arrays) are consecutively connected with a number of phase shifters (65) that connect the ports of a cluster ( receiver array) with the corresponding ports of the other cluster (transmitter array). By correctly selecting the phase shift introduced between the two arrays (arrays), an input beam can be received from a given direction and retransmit the same beam in another direction.
    This application, schematically represented in Figure 6a, includes a power array (64) and a transmission array (62). The radiating elements of the power supply configuration are designed so that they are able to effectively illuminate the transmission cluster of the receiving aperture (i.e., it exhibits spill-over-limited overflow losses). The receiving opening of the transmission group is composed of a first receiving group (68) of cut elements organized into radiating elements of the elementary cell; in the same way, the transmitting opening of the transmission group is composed of a second transmitting group (69) of cut elements organized in radiating elements of the elementary cell. The receiving elements (66) are connected to the homologous transmission elements (67) through a phase shifter (65).
    Each element of the feed grouping is capable of transmitting simultaneously in the four colors (two polarizations and two frequencies). Each color is filtered at the local level by compensation between the elements receiving the cut to subsequently be properly outdated (or delayed in time) and recombined by the elements to the cut in transmission. The phase shift introduced is such that it allows converting the received wavefront into a new flat wavefront with a different beam pointing for each color. In this way, the radiation direction is independent for each of the four beam colors, and the antenna is capable of generating all the necessary beams with a single aperture.
    Third embodiment This third embodiment, or application of the present invention, comprises a multi-beam antenna based on one or more feed groups that illuminate one or more reflection groups -reflectarrays-composed of radiating elements, the same that make up the elements interlaced to the cut .
    In this configuration, as can be seen in Figure 7a, the grouping (array) is used as a mirror in the sense that the incident beams are reflected by the structure. For a normal mirror, the direction of reflection would follow Snell's law, but in a reflection group like the one proposed in this third embodiment, the direction of the reflected beams can be adjusted by properly selecting the value of the connected phase shifters (75) to the short circuits.
    This embodiment, schematically represented in Figure 7a, includes a power array (74) and a reflection array (72). The radiating elements of the power configuration are designed so that they are able to effectively illuminate the opening of the cluster in reflection. The opening of the array in reflection is made up of the cut elements organized into radiant elements of the elementary cell. The ports of the radiating elements to the cut are connected to the phase shifters - delay lines - terminated in short circuit, as can be seen in Figure 7b.
    Each element of the feed grouping is capable of transmitting simultaneously in the four colors (two polarizations and two frequencies). Each color is filtered locally, at reception, by the elements radiating to the cut, duly offset (or delayed in time) after reflection, and are duly recombined by the elements to the cut in transmission. The phase shift introduced is that necessary to convert the received wavefront to another flat wavefront with a different beam pointing for each different color. Also in this case the radiation direction is independent for each of the four colors, and the antenna is capable of generating all beams with a single aperture.
    In the embodiments presented above by way of example, two linear polarizations have been considered. However, the extension to a circular polarization could easily be obtained for the three proposed applications by introducing 90 ° hybrid couplers (3-dB) in the elementary cell of the radiating elements, as described below for each one of the realizations:
    In the first embodiment, pairs of radiating elements at the cut that operate at the same frequency and with orthogonal linear polarizations are connected to the output of the 3 dB hybrid coupler that has as input two circularly polarized signals at the same frequency.
    In the second application, it is assumed that the power group illuminates the group in reception with linearly polarized and frequency multiplexed signals. The elements at the cut of the first grouping or rear grouping receive signals independently in a single linear polarization and frequency. After choosing the appropriate phase, the signal feeds a 3 dB hybrid coupler whose outputs are connected to pairs of radiating elements at the cut of the second grouping or frontal grouping that operates at the same frequency and with orthogonal linear polarizations, thus generating a field circularly polarized Thus, in the case of a design example with a four-color frequency / polarization reuse, the grouping into
    Transmission generates four circular polarizations from the four linear polarizations entering the system.
    In the third application, it is assumed that the power cluster illuminates the cluster in reflection with circularly polarized and frequency multiplexed signals. The pairs of radiant elements to the cut that operate at the same frequency and with orthogonal linear polarizations, are connected to a 3 dB hybrid coupler whose outputs are two orthogonal signals with circular polarization. A phase shifter of different phase is added to the two outputs. Via reflection, the two signals pass again through the phase shifters and enter the coupler at 3 dB from the opposite direction, thereby generating orthogonally polarized fields with the necessary offset.
    In the embodiments presented above as an example, a four-color frequency / polarization reuse scheme with contiguous frequencies has been considered. In particular, the frequencies considered are both in transmission or reception, but in a hybrid transmission / reception configuration, using as an example a configuration with two Ka frequency bands and one centered at 20 GHz and the other centered at 30 GHz, the radiators adjacent cuts of the same elementary cell would be considerably separated in frequency, so that the electromagnetic interactions would be considerably reduced and the behavior of the system would be improved. In turn, it is possible to use the solution proposed by the present invention with more than four frequency / polarization colors using the same elementary cell.
    On the other hand, in addition to the main applications described above, the solution proposed by the present invention can be used in additional configurations, such as those indicated below:
    In the basic structure of the radiator shown in Figures 2 and 3, the input power is injected into the four elementary radiating elements with a coaxial waveguide, but said description is not limiting and in fact, different types of feeding by waveguide. As an illustrative example, in another embodiment of the invention a structure is used where the input waveguide is a double ridge type guide, with a section in the form of .oH ". In particular, the waveguide double ridge - which can also be used in the configurations of the transmitting and receiving arrays or arrays - helps to make a simpler fabrication and assembly of the entire antenna.In addition, the use of the double ridge guide as an input guide results in a structure in which there are only two types of junctions between waveguides, that is, the junction between the ridge waveguide and the empty square guide, and the junction between the four openings to the cut and the free space. therefore a significant simplification of the electromagnetic simulation effort, which translates into a reduction in the design time and cost of the proposed solutions.
    Unlike the previous structures, where the radiator has always referred to infinite or very large periodic clusters, Figure 23 shows a possible configuration in which a single elementary radiating cell, with four radiating elements, is used as a basic block construction for a four-color horn, rectangular (230) or circular (231).
    The basic structure of the radiator, shown in the previous embodiments, has generally been used as an infinite (or large) periodic grouping composed of metal waveguide structures. However, the same basic concept can be implemented using multilayer printed circuits.
    (240) (peS), as shown in Figure 24. The structure shown in Figure 24 describes a direct radiation array or array equivalent to the original structure shown in Figures 2 and 3. Therefore, so similar to that described about the original structure of Figures 2 and 3, the basic structure of Figure 24 can also be modified to become a grouping / array of the reflector or "reflectarray" and transmitter "or transmitarray" type. In addition, although the structure of Figure 24 only uses stacked PCBs, the possibility of using a combination that integrates layers of metal guides with stacked PCSs is also contemplated.
    Some preferred embodiments of the invention are described in the dependent claims that are included below.
    In this text, the word "understand" and its variants (such as "understanding", etc.) should not
    be interpreted in an exclusive way, that is, they do not exclude the possibility that what is described includes
    other elements, steps, etc.
    The description and drawings simply illustrate the principles of the invention. Therefore, it should be appreciated that those skilled in the art will be able to devise various provisions that, although not explicitly described or shown herein, represent the principles of the invention and are included within its scope. In addition, all the examples described in this document are provided primarily for pedagogical reasons to help the reader understand the principles of the invention and the concepts contributed by the inventor (s) to improve the technique, and should be considered as non-limiting with respect to such examples and conditions specifically described. In addition, everything stated in this document related to the principles, aspects and embodiments of the invention, as well as the specific examples thereof, encompass equivalences thereof.
    Although the present invention has been described with reference to specific embodiments, those skilled in the art should understand that the foregoing and various other changes, omissions and additions in the form and detail thereof can be made without departing from the scope of the invention such as defined by the following claims.
    权利要求:
    Claims (14)
    [1]
    1.-Radiant cell for a multi-beam antenna comprising four radiating elements interwoven with each other and with their longitudinal axes in parallel, so that the radiating cell has a square cross section and where each of the four radiating elements is arranged rotated 90 ° with respect to its longitudinal axis in relation to its two adjacent radiating elements, where each of the radiating elements comprises:
    - a port, disposed at a free end of the radiating element, configured to receive an input signal;
    - a first waveguide section that connects the port with a first resonator;
    - a first waveguide resonator with double ridge, arranged next to the first waveguide section connected to the port;
    - a second waveguide section with square cross-section, next arranged to the first waveguide resonator with double ridge;
    - a second waveguide resonator with double ridge, arranged next to the second waveguide section of square cross section;
    - a third waveguide section with square cross-section, arranged between the second waveguide resonator with double ridge and a radiation aperture;
    where each of the radiating elements is configured to operate signals with a certain frequency band and a certain polarization.
    [2]
    2. Radiant cell according to claim 1, wherein the 4 radiating elements are configured to operate signals of 4 different colors, one color for each radiating element, where each color is formed by the combination of a selected frequency between two different frequencies. and a polarization selected from two different polarizations, where said signals are orthogonal in frequency and in polarization response.
    [3]
    3. Radiant cell according to any of the preceding claims wherein the first waveguide section of the radiating elements is selected between a coaxial waveguide with square cross section and a double ridge waveguide.
    [4]
    4.-Horn to feed a multibeam antenna, wherein the horn comprises at least one radiating cell according to any of the preceding claims.
    [5]
    5. System according to any of the preceding claims, comprising a first plurality of said radiating cells arranged in a grid structure, wherein the arrangement comprises a single radiation opening equal to the sum of the openings
    of radiation of the radiating elements of the radiating cells of the arrangement.
    [6]
    6. System according to claim 5, further comprising a signal distribution network connected to the grid structure, wherein said distribution network is configured to provide an input signal with a certain color to the port of the corresponding radiating element.
    [7]
    7. System according to claim 6, wherein the grid structure comprises a plurality of groups of radiating cells, wherein each of the groups comprises interconnections between the radiating elements operating with the same color of the radiating cells of the grouping, so that each grouping forms a beam associated with a color, with an offset phase center L / 2 with respect to the phase center of the adjacent homologous radiating cell cluster, where L is the grouping dimension.
    [8]
    8. System according to claim 6, wherein the grid structure comprises a plurality of groups of radiating cells, wherein each of the groups comprises interconnections between the radiating elements operating with the same color of the radiating cells of the grouping, so that each grouping forms a beam associated with a color, with an offset phase center with respect to the phase center of the adjacent homologous radiating cell cluster so that the phase centers are arranged according to a triangular structure
    [9]
    9. System according to any of the preceding claims 7-8 which further comprises a parabolic reflector element configured to reflect the beams formed by the radiating cell clusters.
    [10]
    10. System according to any of claims 5-9, wherein one or more radiating cells of the plurality of radiating cells arranged in the grid structure has a degree of reuse equal to 4, where the degree of reuse of a cell Radiant is associated with the number of beams of those participating in its conformation.
    [11]
    11. System according to any of claims 5-10 comprising a second plurality of radiant cells identical to the first plurality, arranged consecutively to the first plurality in a parallel plane, which further comprises a plurality of interconnecting phase shifters each radiating element of the radiating cells of the first plurality of radiating cells with a homologous radiating element of the second plurality of radiating cells.
    [12]
    12. System according to any of claims 5-10, further comprising a plurality of phase shifters, wherein each phase shifter of the plurality of phase shifters 5 is connected at one end to a radiating element of a radiating cell of the first plurality of cells. radiant and at the opposite end is connected to a short circuit.
    [13]
    13. System according to any of the preceding claims, wherein the radiating cells of the first plurality of radiating cells comprise at least one 90 ° hybrid coupler configured to operate with circular polarizations.
    14. System according to any of the preceding claims, wherein the system is configured to operate with a first plurality of transmission frequency bands and a second plurality of reception frequency bands.
    [15]
    15. System according to any of claims 5-14 comprising a plurality of printed circuits, wherein each of the printed circuits is
    15 implemented with functionality identical to that of a radiant cell.
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    同族专利:
    公开号 | 公开日
    WO2019002641A1|2019-01-03|
    ES2647279B2|2018-06-21|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US20100207833A1|2008-12-18|2010-08-19|Agence Spatiale Europeene|Multibeam Active Discrete Lens Antenna|
    US20100259346A1|2009-04-13|2010-10-14|Viasat, Inc.|Dual-polarized multi-band, full duplex, interleaved waveguide antenna aperture|
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    ES201730838A|ES2647279B2|2017-06-26|2017-06-26|Radiant cell for multi-beam antenna|ES201730838A| ES2647279B2|2017-06-26|2017-06-26|Radiant cell for multi-beam antenna|
    PCT/ES2018/070401| WO2019002641A1|2017-06-26|2018-06-01|Radiating cell for multibeam antenna|
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