Antenna array apparatus with duplex architecture

Abstract

An antenna array apparatus (1) with duplex architecture, comprising: a plurality of antenna elements (11) arranged in a planar configuration on a panel (10), wherein the plurality of antenna elements comprises a first subset of antenna elements defining a receiver, Rx, array (13), and a second subset of antenna elements defining a transmitter, Tx, array (14); and a decoupling arrangement (100) comprising a periodic structure configured on the panel to counteract nearfield coupling between the Rx array and the Tx array.

Description

[0001] ANTENNA ARRAY APPARATUS WITH DUPLEX ARCHITECTURE

[0002] Technical field

[0003] This disclosure relates to the field of antenna arrays with duplex architecture, comprising a plurality of antenna elements arranged in a planar arrangement. A first subset of the antenna elements defines a receiver array, and a second subset defines a transmitter array.

[0004] Background

[0005] Broadly speaking, antenna arrays comprising a plurality of antenna elements may have the benefit of being configured to combine radio signal components received in a multitude of the antenna elements so as to obtain selectable spatial sensitivity for monitoring radio signal reception in various directions. Correspondingly, in transmission, a multitude of the antenna elements may be configured to transmit radio signal components such that they constructively combine to obtain concentration of radiated power in one or more selected directions. In an antenna array apparatus with duplex architecture, different subsets of antenna elements may operate concurrently, where one subset defines a receiver array, and a second subset defines a transmitter array.

[0006] One use of antenna arrays is in wireless communication, such as radio communication. In wireless communication, a wireless channel is used to transfer information and data between different nodes acting as transmitter and receiver, using an electromagnetic wave signal. It is therefore beneficial if the wireless channel is constructed to ensure that the signal successfully reaches the receiver. Besides applying sufficient transmit power, the use of antenna arrays is advantageous, as it allows for so- called beamforming, whereby transmitted energy may be focused and directed towards the receiver. Beamforming and beam management has been more frequently considered since the development of the so-called 5G version of wireless communication under supervision of the 3rdGeneration Partnership Project (3GPP), and particularly for use in the mm wave spectrum. An antenna array apparatus with duplex architecture may be employed at various radio nodes of a wireless communication system. The antenna array may be reconfigurable, wherein the antenna elements may be suitably fed such that a combined bearer is obtained with suitable directional properties according to a beamforming pattern. In some examples, such an antenna array apparatus may be used at a radio base station. Another type of device of similar technology is a panel station or forwarding station, herein referred to as a coverage-enhancing device (CED), configured to forward a signal from a transmitter radio node towards a receiver radio node. By way of example, such a CED is sometimes referred to as a Reconfigurable Intelligent Surface (RIS), alternatively a Large Intelligent Surface (LIS). Such CEDs using reconfigurable panels aim to influence the wireless channel in a passive or active way, wherein its antenna elements, arranged in an array, reflect electromagnetic waves with a digitally configurable phase shift, and possibly with gain (active RIS). Such CEDs are typically designed to reflect impinging electromagnetic waves, though they can also be designed to transmit impinging electromagnetic waves or be transmissive to deflect impinging electromagnetic waves passing through the panel of the CED. In order to relay the signal from the transmitter radio node to the receiver radio node, the CED applies a beamforming pattern.

[0007] A challenge in the art of antenna arrays with duplex architecture is related to mutual coupling between transmitter array and receiver array, particularly nearfield coupling. Such coupling may result in limitation of obtainable or maximum gain of the antenna array apparatus. This is particularly related to scenarios where the transmitter array and receiver array are positioned close to each other, such as configured on the same panel or on adjacent panels. There is thus need for improvement of antenna array apparatuses with duplex architecture, e.g., in the context of obtainable gain, with the objective to enhance coverage and improve spatial multiplexing capability.

[0008] Summary

[0009] The general object outlined above is overcome by providing an antenna array apparatus in accordance with the claims. According to one aspect, the antenna array arrangement comprises: a plurality of antenna elements arranged in a planar configuration on a panel, wherein the plurality of antenna elements comprises a first subset of antenna elements defining a receiver, Rx, array, and a second subset of antenna elements defining a transmitter, Tx, array; and a decoupling arrangement comprising a periodic structure configured on the panel to counteract nearfield coupling between the Rx array and the Tx array.

[0010] The proposed solution allows for improved operation of the antenna array apparatus, in particular at large angles with respect to boresight. The decoupling arrangement, which is configured to provide isolation between subarrays, facilitates spatial multiplexing, enabling the simultaneous transmission of multiple data streams in many different directions, leading to higher spectral efficiency.

[0011] Various additional features are set out in the dependent claims.

[0012] Brief description of the drawings

[0013] Various examples will be described with reference to the drawings, in which:

[0014] Fig. 1 schematically illustrates an antenna array apparatus according to the proposed solution;

[0015] Fig. 2 schematically illustrates an antenna array apparatus according to the proposed solution, further configured for full duplex operation;

[0016] Fig. 3 schematically illustrates coupling between a Tx array and an Rx array at large angles relative to boresight of the panel;

[0017] Fig. 4 shows a configuration of an antenna array;

[0018] Fig. 5A shows an antenna array apparatus with a decoupling arrangement according to one example of the proposed solution;

[0019] Fig. 5B illustrates a decoupling effect obtained by a solution configured according to Fig. 5A;

[0020] Fig. 6A shows an antenna array apparatus with a decoupling arrangement according to another example of the proposed solution;

[0021] Fig. 6B illustrates a detail from the drawing of Fig. 6A;

[0022] Fig. 7A illustrates a mathematical representation of an array configured according to Fig. 4; Fig. 7B illustrates a mathematical representation of an array configured according to Fig. 5A;

[0023] Fig. 8 shows an antenna array apparatus with a decoupling arrangement according to another example of the proposed solution;

[0024] Fig. 9 illustrates a detail from the drawing of Fig. 8;

[0025] Fig. 10 illustrates details from the drawings of Figs 8 and 9;

[0026] Fig. 11 illustrates diagrams indicating the obtained decoupling effect;

[0027] Fig. 12A shows an alternative embodiment of the antenna array apparatus of Fig. 8;

[0028] Fig. 12B shows another alternative embodiment of the antenna array apparatus of Fig. 8;

[0029] Fig. 13 illustrates a use case of the antenna array apparatus according to the proposed solution.

[0030] Detailed description

[0031] In the following description, for purposes of explanation and not limitation, details are set forth herein related to various examples. However, it will be apparent to those skilled in the art that the present disclosure may be practiced in other examples that depart from these specific details. In some instances, detailed descriptions of well- known devices, circuits, and methods are omitted so as not to obscure the description of the present disclosure with unnecessary detail. The functions of the various elements including functional blocks, including but not limited to those labeled or described as “computer”, “processor” or “controller”, may be provided through the use of hardware such as circuit hardware and / or hardware capable of executing software in the form of coded instructions stored on computer readable medium. Thus, such functions and illustrated functional blocks are to be understood as being either hardware-implemented and / or computer-implemented and are thus machine-implemented. In terms of hardware implementation, the functional blocks may include or encompass, without limitation, digital signal processor (DSP) hardware, reduced instruction set processor, hardware (e.g., digital or analog) circuitry including but not limited to application specific integrated circuit(s) (ASIC), and (where appropriate) state machines capable of performing such functions. In terms of computer implementation, a computer is generally understood to comprise one or more processors or one or more controllers, and the terms computer and processor and controller may be employed interchangeably herein. When provided by a computer or processor or controller, the functions may be provided by a single dedicated computer or processor or controller, by a single shared computer or processor or controller, or by a plurality of individual computers or processors or controllers, some of which may be shared or distributed. Moreover, use of the term “processor” or “controller” shall also be construed to refer to other hardware capable of performing such functions and / or executing software, such as the example hardware recited above.

[0032] The drawings provide performance plots and are otherwise to be regarded as being schematic, where representations and elements illustrated in the drawings are not necessarily shown to scale. Rather, the various elements are represented such that their function and general purpose become apparent to a person skilled in the art. Any connection or coupling between functional blocks, devices, components, or other physical or functional units shown in the drawings or described herein may also be implemented by an indirect connection or coupling. A coupling between components may also be established over a wireless connection. Functional blocks may be implemented in hardware, firmware, software, or a combination thereof.

[0033] Generally speaking, the antenna array apparatus according to the proposed solution may be used for concurrent or overlapping reception and transmission of an electromagnetic wave signal, or signal for short. This may e.g. apply in a scenario where the antenna array apparatus is used by a base station to transmit and receive signals. In some examples, the antenna array apparatus may be employed for deflecting an incoming signal. The antenna array apparatus may in such an example also add gain to a received signal before transmitting it. This may e.g. apply in a scenario where the antenna array apparatus is used in a CED to convey or forward signals. In some examples, the antenna array apparatus may be employed for transmitting a signal and concurrently monitoring reception of a signal, such as for sensing of objects in the environment, e.g. in a radar application.

[0034] An antenna array is as such a known concept, which uses a configuration of multiple antennas or antenna elements arranged in a systematic pattern to achieve desired characteristics such as increased gain, improved directivity, beamforming, or diversity reception / transmission. The individual antennas in the array are spaced apart in a precise manner to exploit the constructive interference of electromagnetic waves, thereby enhancing certain properties of the antenna system. The antenna array technology may be used for improving performance of wireless communication systems by focusing the signal, or sensitivity of receiving signals, in a specific direction, increasing signal strength, reducing interference, or enabling spatial diversity reception. As noted, a beneficial feature of antenna arrays is the possibility of obtaining beamforming. Beamforming is a signal processing technique used in antenna arrays to focus the transmission or reception of electromagnetic waves in a specific direction. It may involve adjusting the phase and / or amplitude of the signals transmitted or received by each antenna element in the array in such a way that the waves from different elements constructively interfere in the desired direction, while cancelling out or minimizing interference from other directions. Basic function and character of antenna arrays, as well as the concept of beamforming, are well known in the art and will therefore not be described in greater detail herein.

[0035] Fig. 1 schematically shows an example of an antenna array apparatus 1 with duplex architecture. In the context of the proposed solution, the antenna array apparatus 1 comprises at least one receiver (Rx) array 13 and one transmitter (Tx) array 14. Each array comprises a plurality of antenna elements (or antennas) 11 arranged on a panel 10. That is, each of the at least one Rx array 13 and one Tx array 14 are defined by a respective plurality, or subset, of antenna elements (or antennas) 11. An amplifier unit 12 may be included, connecting the Rx array 13 with the Tx array 14. A control unit 20 may further be included, configured to control the antenna array to accomplish beamsteering.

[0036] Fig. 2 schematically shows a further example of an antenna array apparatus 1 with duplex architecture, which reuses terms described with reference to Fig. 1. In this context, the antenna array apparatus may further be configured for duplex operation of conveying communication signals, such as in a CED (e.g., an active RIS) capable of independent uplink (UE) and downlink (DL) operation. The antenna array may thus comprise a first pairing of a first Rx array 13 and a first Tx array 14, e.g., for UL, and a second pairing of a second Rx array 15 and a second Tx array 16, e.g., for DL. In addition to the first amplifier unit 12, described with reference to Fig. 1 and connecting the first Rx array 13 with the first Tx array 14, a second amplifier unit 12-2 may connect the second Rx array 15 with the second Tx array 16. The panel 10 carrying the antenna elements 11 may be a single panel, or comprise subpanels arranged adjacent to each other. In this context, separate Rx and Tx subpanels may be provided. The panel 10 may thereby be referred to as a multi-panel.

[0037] Fig. 3 schematically illustrates operation of an example of the antenna array apparatus 1, showing beamforming using one Rx array 13 and one Tx array 14. It should be noted that the drawing is schematic, and not to scale. Both arrays may be configured to have flexible beam-steering scanning, by control using the control unit 20, to direct sensitivity to different directions. This may be used to specifically increase or focus spatial sensitivity towards a target 30. In this context, it may be noted that the target 30 may be a radio node, such as a base station or a UE, in the case of wireless signaling or communication. In other examples, the target 30 may be a passive reflecting object, e.g., in the context of wireless sensing or radar operation.

[0038] Specifically, when wide angles are configured, illustrated in the drawing as spatial sensitivity towards the target 30, space wave coupling is likely to occur, and the beams may excite strong surface wave coupling. In this context, space wave coupling may comprise near field coupling over the air. Additionally, surface wave coupling may occur on the panel 10, which may comprise a printed circuit board (PCB) on which the antenna elements 11 are formed. A consequence may be that the Tx and Rx beams will overlap, and the beam from Tx array 14 will be received directly by the Rx array 13. The surface wave coupling may further reduce the array gain of Tx and Rx. The coupling level becomes high when beam-steering angle is larger than 40-55 degrees, with reference to a normal direction from the panel 10. Due to the sidelobes, the mutual coupling between Tx and Rx panel are higher, the allowed power amplification is limited by this parameter. Specifically, when the target 30 is positioned in a direction 9 that has a large angle to boresight direction, the coupling between Tx and Rx is very strong, including space wave coupling component and surface wave coupling component, where the space wave coupling is dominant. As noted, the transmitted signals will be directly received by the Rx. When the beams point to the largest angle, the sidelobe level (of the respective Rx and Tx beams) will be higher than that in boresight direction, which leads strong mutual coupling between Tx and Rx. That means when the beams of Tx array 14 and the Rx array 13 point to largest angle, it has the strongest coupling. Hence, the coupling between Tx and Rx has to be reduced especially when the beams of Tx and Rx point to large angle to boresight direction. Specifically, over-the-air coupling needs to be addressed to obtain improved isolation against mutual coupling, which may include space wave direct beam coupling but particularly sidelobe coupling.

[0039] A solution for obtaining decoupling is therefore desirable. In order to improve the array scanning with a good gain, isolation at all scanning angle of beam-steering needs to be improved.

[0040] For this purpose, an antenna array apparatus 1 with duplex architecture is proposed, comprising: a plurality of antenna elements 11 arranged in a planar configuration on a panel

[0041] 10, wherein the plurality of antenna elements 11 comprises a first subset of antenna elements defining an Rx array 13, and a second subset of antenna elements defining a Tx array 14; and a decoupling arrangement comprising a periodic structure configured on the panel to counteract nearfield coupling between the Rx array 13 and the Tx array 14.

[0042] Various examples and details associated with the proposed antenna array apparatus will be described going forward.

[0043] Fig. 4 schematically illustrates an antenna array comprising an Rx array 13 and a Tx array 14, as explained in the foregoing. Each array comprises 4x4 antenna elements

[0044] 11, by way of example. The Rx array and the Tx array are arranged on a common panel

[0045] 10, which may comprise adjacent sub-panels. This drawing represents a state of the art configuration, which may lead to unwanted over-the-air coupling, particularly for large beam angels, as explained. The antenna elements 11 are arranged in a planar configuration on the panel 10, meaning that they are arranged in a common, or substantially common, plane. The panel 10 comprises a carrier for the antenna elements

[0046] 11, such as a PCB. The antenna elements may be formed on the carrier by coating or deposition of conductive material, or as separate components soldered or otherwise attached to the carrier. The antenna elements 11 may further be arranged in a configured pattern, having a size adapted to an operation wavelength, such as 1 / 4 of that wavelength, and with a predefined gap between adjacent antenna elements 11 according to the planar configuration, such as about 1 / 2 of said wavelength.

[0047] Various aspects of the proposed solution will be described below with reference to the drawings. The proposed solution thus involves a decoupling arrangement for an antenna array apparatus. For the sake of simplicity, the examples will mainly be described based on the example of Fig. 4 and having a corresponding planar configuration of the antenna elements 11, but should not be seen as limited to that configuration. The decoupling arrangement comprises a periodic structure 100 configured on the panel 10 to counteract nearfield coupling between the Rx array 13 and the Tx array 14 by reducing coupling effects as described herein. The periodic structure comprises a plurality of elements, including conductive elements, disposed on the panel 10 adjacent to the antenna elements 11.

[0048] Fig. 5A shows an example of a decoupling arrangement for an antenna array apparatus according to one aspect. Specifically, the plurality of elements of the decoupling arrangement 100 comprises a plurality of parasitic elements on the panel, configured to form the periodic structure to obtain a lateral separation of phase centers of the Tx array and the Rx array.

[0049] In one example, as shown, this is obtained by the parasitic elements comprising parasitic patches 101 arranged outwardly of the adjacent Rx array 13 and the Tx array, adjacent to the antenna elements 11. Each parasitic element may be formed by a conductive element or coating, arranged on the panel 10.

[0050] The parasitic patches 101 are in some examples distributed with a periodicity (of the periodic structure) matching a periodicity of the antenna elements 11, as illustrated. Each parasitic patch 101 may thus form an end element outwardly of a row or column of antenna elements 11, which row / column comprises both Rx elements and Tx elements. The drawing shown an example where the parasitic patches are of the same, or about the same, size and configuration as the antenna elements 11, whereas other configurations are plausible. A little smaller or larger than the size of the antenna elements 11 also works. The objective is to obtain ample induced current on the parasitic patches 101, which serves to move the phase center of the Rx array and Tx array away, and apart from each other. The size (side length) of the parasitic patches 101 is less than 1 / 2 of the wavelength due to dielectric loading, and the side length of the parasitic patches 101 is in some examples between 1 / 4 and 1 / 2 of a center free space wavelength at which the antenna array apparatus is configured to operate. This may be configured dependent on the dielectric constant of the carrier on which the antenna elements 11 and parasitic patches are disposed, and this size range holds for a carrier of a standard FR4 PCB material. Each parasitic patch 101 may have a rectangular or quadratic shape with sides. The periodic structure may in some examples define a pitch between adjacent parasitic patches of about 1 / 2 of said wavelength.

[0051] Fig. 5B schematically shows how shows how periodic structure acts to obtain, or causes, the lateral separation of phase centers of the Tx array 14 and the Rx array 13. Specifically, Fig. 5B shows the Tx array 14 with its antenna elements 11 on the panel (or sub-panel) 10, from a side view corresponding to the embodiment of Fig. 5A. In the drawing, an equiphasic surface 51 is shown, corresponding to the Tx array without the applied decoupling arrangement 100 (i.e., corresponding to Fig. 4). Moreover, the corresponding equiphasic surface 52 is shown, corresponding to the Tx array configured with the decoupling arrangement 100 (i.e., corresponding to Fig. 5A). Since the periodic structure of parasitic patches 101 is arranged outwardly of the adjacent Rx array 13 and the Tx array, each individual array (the Tx array being shown in Fig. 5B) will only be affected in a noticeable way on one side (right, in the drawing). Consequently, a lateral shift dl (i.e., in the plane of the panel 10) of the equiphasic surface is obtained. A corresponding lateral shift is obtained in the opposite direction for the Rx array 13. By means of the lateral shift(s), causing separation of phase centers of the Rx array 13 and Tx array, isolation against over-the-air coupling is improved.

[0052] Returning to Fig. 5A, further improvement may be obtained by including parasitic strips 102 as additional parasitic elements. Experimentation and testing have indicated that this may provide the additional benefit of improved isolation at various beam angles. This is obtained by the parasitic strips 102 causing a change in current phase on the antenna elements 11, which makes the isolation improved when Tx and RX antenna elements 11 have nearly opposite phase.

[0053] In some examples, the parasitic strips 102 extend parallel to a borderline between the Rx array 13 and the Tx array 14, i.e., parallel to columns of the antenna elements 11. The parasitic strips 102 are thus provided in accordance with a periodic structure according to the antenna elements 11, with parasitic strips 102 extending adjacent to columns of antenna elements 11 with one parasitic patch 101 on each side (over and under) outwardly of the respective column.

[0054] The parasitic strips 102 will add suppressing currents which may cause impedance change. However, this effect may be minimized by optimizing a gap between parasitic strip 102 and the adjacent antenna element 11. In this context, the optimization of the size of the gap is carried out by simulations to increase the isolation S21 by changing the phase to be opposite for Tx and Rx antenna elements 11. Here, the known term S21 represents the signal level coupled between Tx port to Rx port via near field, similar to the pathloss for far field. Larger S21 value means higher isolation. The optimization included a simulation process, wherein the isolation level of the Tx / Rx array is simulated when the gap is set at different dimensions. The simulation shows that when at a gap of about 1 mm, such as between 0.5 and 1.5 mm, impedance matching is the best.

[0055] Tests have shown an improvement by accomplishing 17dB isolation at large scanning angles (beam angels) for S-parameter S21, such as over 35 degrees, or beyond. The lateral shift dl obtained using the proposed solution is the largest at the largest beam scanning angle. The parasitic patches 101 and the strips 102 both contribute to the isolation improvement, and the combined decoupling scheme of loading parasitic patches 101 and strips 102 is preferred.

[0056] According to some aspects of the proposed solution, the periodic structure of the decoupling device is configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path, between the Rx array 13 and the Tx array 14. Moreover, according to some aspects, the periodic structure may extend at least between the Rx array 13 and the Tx array 14.

[0057] Fig. 6A schematically illustrates one example of the antenna array apparatus according to those aspects, specifically a decoupling arrangement for an antenna array apparatus, based on the example of Fig. 4. The decoupling arrangement comprises a periodic structure 100 configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path, to counteract nearfield coupling between the Rx array 13 and the Tx array 14 configured on the panel 10.

[0058] Specifically, the decoupling arrangement 100 comprises a plurality of parasitic elements in the form of capacitive strips 110 on the panel. Fig. 6B shows a close-up view of an example of one strip 110. Each capacitive strip 110 is divided into segments 111, configured according to said periodic structure.

[0059] In some examples, as shown in Fig. 6A, each segment 111 extends alongside two adjacent antenna elements 11. A gap 112 between successive segments 111 is formed in the parasitic strip, wherein the gap 112 is located at, i.e., alongside, each antenna element 11. Moreover, each segment 111 comprises a plurality of separate and parallel sub-strips 112, extending along said capacitive strip. Each sub-strip 112 forms a separate parasitic element.

[0060] According to the embodiment described with reference to Figs 6 A and 6B, the capacitive strips 110 are closely positioned at the edge of and respectively surrounding the Rx array 13 and the Tx array 14, adjacent to the antenna elements 11, to form a second coupling path besides the original coupling path between those arrays. A capacitance between radiation patches (antenna elements 11) and the capacitive strips 110 is formed so that a phase delay of 90° is generated. Correspondingly, a phase delay of 180°, caused by the capacitance between Rx array 13 and its surrounding strips 110, and the capacitance between the Tx array 14 and its surrounding strips, is generated in the second coupling path. Therefore, the coupling components of two coupling paths can be cancelled with each other, thereby reducing the coupling between the Rx array 13 and the Tx array 14. Even though the antenna array has function of beam-steering, the second coupling path always has a phase difference of 180° with original coupling path so that the coupling of Tx / Rx array can always been reduced.

[0061] Figs 7 A and 7B are referred to below, to further describe the decoupling principle upon which the antenna array arrangement according to various examples of the proposed solution is based, such as the examples provided in Figs 6A and 6B.

[0062] Figs 7 A and 7B provide the CS loading decoupling principle using a two-element example. An original array is presented in Fig. 7A (principally corresponding to Fig. 4), wherein Fig. 7B represents an array according to the proposed solution, implementing ta configuration exemplified in Figs 6A and 6B. We can find it has a direct coupling path between two array elements. Assuming the original coupling has an amplitude of a, and phase of 0, the S-parameters matrix can be expressed as:

[0063] The capacitance between antenna and strip can be seen as a phase shifter. The value of the phase delay is 0X= 90°. The new S-parameters matrix can be calculated as: Where, the coupling of the second path can be expressed as:

[0064] Here, the b is the coupling coefficient amplitude between original patch and capacitive strip, according to Fig. 7B.

[0065] The total coupling of the Tx / Rx array after loading CS can be expressed as:

[0066] The formula (3) also illustrates that the coupling of second coupling path always has a phase delay of 180°no matter what directions the beams of Tx / Rx point. Moreover, the formula (5) demonstrates that the coupling of Tx / Rx can be perfectly reduced after generating the second coupling path by loading CS, which has a phase delay of 180°to enable the perfect cancellation between the second and original coupling paths. Additionally, the formula (5) repeals that the phases of the array before and after decoupling almost keep unchanged, which is the unique characteristic of our proposed decoupling method in this paper. The phase-invariant property of array before and after decoupling is a distinguished characteristic from other decoupling methods of coupling component propagation suppression. Because the surface wave coupling component suppression contributes to the change of total coupling, which typically is derived from the superposition of surface wave and space wave vectors, where these two coupling components have different phases.

[0067] The parasitic strips 110 are preferably configured very close to the adjacent antenna elements 11, such as between 2 and 3% of the wavelength of the antenna array. By way of example, the distance between the parasitic strips 110 and the antenna elements 11 is just below 2mm at 4Ghz. Tests of a model and prototype according to the example of Figs 6A and 6B, with surrounding capacitive strips 110, have indicated that matching remains, and that isolation has improved 15dB at a 44-degree angle. In these tests, antenna elements with a side length a of 20.8 mm were printed on a top surface of an RO 4350B substrate, serving as carrier of the panel 10, wherein a spacing between the antenna elements 11 was 38 mm. According to the decoupling arrangement, 5 columns of sub-strips 112 were further printed to form the capacitive strip 110. The capacitive strip 110 surrounds the respective Rx array 13 and Tx array 14 and is configured to be separated into the segments 111. Each segment 111 is 38,4 mm long, and a gap of 4 mm is formed between adjacent segments 111. Each sub-strip 112 has a width of 0.5 mm and a spacing between adjacent sub-strips 112 is equally 0.5 mm. The capacitive strips 110 were employed close to the antenna elements 11 with a gap of 2 mm (0.0067% of the wavelength at 4GHz) to form capacitance.

[0068] Another example will now be described, based on the aforementioned aspect of the proposed solution, wherein the periodic structure of the decoupling device is configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path, between the Rx array 13 and the Tx array 14.

[0069] Fig. 8 schematically illustrates a perspective view of another example of the antenna array apparatus according to those aspects, specifically a decoupling arrangement for an antenna array apparatus. The antenna array apparatus comprises a periodic structure 100, arranged adjacent to the antenna elements 11, configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path, to counteract nearfield coupling between the Rx array 13 and the Tx array 14 configured on the panel 10. The periodic structure 100 extends at least between the Rx array 13 and the Tx array 14. Specifically, the decoupling arrangement 100 comprises a meta surface wall 120, standing upright from the panel and comprising the periodic structure.

[0070] As is seen in Fig. 8, the meta surface wall 120 comprises a plurality of cells 130 configured according to said periodic structure to create coupling paths of opposing phase between the Rx array 13 and the Tx array 14.

[0071] Fig. 9 illustrates this configuration of the meta surface wall 120 more clearly, and that the cells 130 comprise two types of cells, or units, 131 and 132. Each cell 130 comprises a multilayer structure 121-125, as will be described further with reference to Fig. 10 below. The different types of cells 131, 132 may be configured in an alternating arrangement along the meta surface wall 120, as shown. The drawing indicates the decoupling principle used, wherein the cells 131, 132 of the meta surface wall 120 provides a polarization rotation surface. Path 1 is obtained by components passing through cells 131 with a phase of 9, whereas Path2 is obtained by components passing through cells 132 with a phase of 9 +180°. Hence, these components will combine destructively and optionally result in cancellation, to obtain decoupling.

[0072] Fig. 10 shows one cell 130, which thus forms one unit of the meta surface wall 120. The meta surface wall 120 comprises a side strip 121 at a first side. As can be seen in Fig. 9, this side strip may be shared by all cells 130 of the same meta surface wall 120. At the opposing side of the meta surface wall 120, individual patch elements 122 are configured for each of the cells 131, 132, thus defining the individual cells or units. For each cell 130, the side strip 121 and the patch elements 122 on the opposing side of the meta surface wall 120, are configured to operate as a polarization rotator. A middle layer 123 is further comprised, comprising an aperture structure or grid 124 with a lattice which toggles orthogonally between the cells 131, 132 according to the periodic structure. This way, the alternating arrangement along the meta surface wall 120 is obtained, at which alternating opposite phase is accomplished.

[0073] The middle layer 123 may further comprise dielectric members 125, 126, separating the aperture grid 124 from the side strip 121 and the individual patch elements 122. In some examples, the meta surface wall 120 projects less than 1 / 3 of a wavelength of operation of the antenna array apparatus 100, such as 1 / 4 of said wavelength.

[0074] In some examples, where the meta surface wall 120 is configured on one of the arrays 13, 14, the side strip 121 may be directed away from the other one of the arrays 13, 14.

[0075] Fig. 11 shows diagrams indicating the decoupling effect obtained by a decoupling arrangement according to this aspect of the proposed solution, comprising the meta surface wall 120 having a plurality of cells 130 configured according to said periodic structure 131, 132 to create coupling paths of opposing phase between the Rx array 13 and the Tx array 14.

[0076] Various alternative configurations of the antenna array apparatus 1 according to the proposed solution are plausible, comprising the meta surface wall 120 as described. Specifically, the meta surface wall may comprise a plurality of wall members at each of the subsets of antenna elements 11, i.e., both on the Rx array 13 and on the Tx array 14, comprising wall members extending between columns of the antenna elements 11. Said wall members may extend parallel to a border line between the Rx array 13 and the Tx array 14. In this context, for each column of antenna elements 11 on one of those arrays 13, 14, the decoupling arrangement comprises one upright wall member extending alongside said column of antenna elements 11 and between that column and the other antenna array 13,14. This corresponds to the decoupling arrangement that has already been shown in Fig. 8. By way of example, the following alternative examples may be noted (reference numerals not repeated, reference is made to the preceding drawings).

[0077] Fig. 12A shows a configuration of the decoupling arrangement, wherein a single wall member is arranged between each column of antenna elements (as opposed to the embodiment of Fig. 8, where two wall members are provided between adjacent columns of Rx antenna elements and Tx antenna elements). This configuration may provide a greater freedom of design, as the same pattern of antenna elements 11 and wall members of the meta surface wall 120 is configured throughout the panel 10. This may be particularly beneficial where the control unit 20 is configured to selectively configure the antenna elements 11 to form part of one anyone of the Rx array 13 or the Tx array 14.

[0078] Fig. 12B shows a configuration corresponding to that of Fig. 12A, but where wall members are further arranged between each row of antenna elements. It may be noted that the corresponding arrangement may be applied for the embodiment of Fig. 8. This configuration may be suitable for a full duplex antenna array apparatus 1 according to claim 2, to obtain decoupling between each adjacent array 13, 14, 15, 16 of the panel

[0079] 10. In such embodiments, said wall members encompass each of the antenna elements

[0080] 11.

[0081] With reference to the control unit 20 of the antenna array apparatus 1, shown in Figs 1 and 2, the control unit may implement logic circuitry configured to control the antenna array apparatus 1, e.g. for configuration of the antenna elements to obtain beam- steering. The logic circuitry may include a processing device 21, including one or multiple processors, microprocessors, data processors, co-processors, and / or some other type of component that interprets and / or executes instructions and / or data. Processing device 21 may be implemented as hardware (e.g., a microprocessor, etc.) or a combination of hardware and software (e.g., a system-on-chip (SoC), an applicationspecific integrated circuit (ASIC), etc.). The processing device 21 may be configured to perform one or multiple operations based on an operating system and / or various applications or programs. The logic circuitry may further include memory storage 22, which may include one or multiple memories and / or one or multiple other types of storage mediums. For example, memory storage 22 may include a random access memory (RAM), a dynamic random access memory (DRAM), a cache, a read only memory (ROM), a programmable read only memory (PROM), flash memory, and / or some other type of memory. Memory storage 22 may include a hard disk (e.g., a magnetic disk, an optical disk, a magneto-optic disk, a solid state disk, etc.). The memory storage 22 is configured for holding computer program code, which may be executed by the processing device 21. Software defined by said computer program code may include an application or a program that provides a function and / or a process. The software may include device firmware, an operating system (OS), or a variety of applications.

[0082] By way of example, Fig. 13 illustrates a field of use for the antenna array apparatus 1 according to the proposed solution. This drawing schematically illustrates a wireless communication scenario, providing an example of a scene in which the solutions provided herein may be incorporated. A wireless network 300 comprises an access network 320, such as a 5G NR access network, usable for communication over an air interface with further stations, such as the wireless device 350. Such wireless devices are commonly referred to as User Equipment (UE). The access network may comprise a plurality of access nodes or base stations 321, 322, configured to provide a wireless interface for connection to, inter alia, the UE 350. For an NR implementation, the base station may be referred to as a gNB. Each base station comprises a point of transmission and reception, referred to as a Transmission and Reception Point (TRP), which coincides with an antenna of the respective base station. Logic for operating the base station may be configured at the TRP or at another physical location. The wireless network 100 further includes a core network 310, to which the access network 320 is connected. The core network 310 is in turn connected to other communication networks 330, such as the Internet.

[0083] The UE 350 may be any device operable to wirelessly communicate with the network 300 through the base stations 321, 322, such as a mobile telephone, computer, tablet, a machine to machine (M2M) device, an loT (Internet of Things) device or other. The UE 350 may be stationary or mobile. An antenna array apparatus 1 is configured to operates as a CED, such as a RIS, is usable for conveying signals between an access node 321 of the access network 320 and further stations, such as the UE 350. The CED 1 may in this context be used in uplink (UL), wherein the UE 350 acts as transmitter and the access node 321 acts as receiver, and / or in downlink (DL), wherein the access node 321 acts as transmitter and the UE 350 acts as receiver. While the drawing of Fig. 13 illustrates a scenario where the CED 1 is operated to convey a signal between the access node 321 and the UE 350, it shall be noted that the CED 1 may alternatively be employed for conveying a signal between two UEs, i.e., in a device-to-device (D2D) setup.

[0084] Various features and explanatory basis for the proposed solution have been outlined in the foregoing. The proposed solution may take any shape as provided herein, including any combination of the items set out below.

[0085] Item 1. An antenna array apparatus (1) with duplex architecture, comprising: a plurality of antenna elements (11) arranged in a planar configuration on a panel (10), wherein the plurality of antenna elements comprises a first subset of antenna elements defining a receiver, Rx, array (13), and a second subset of antenna elements defining a transmitter, Tx, array (14); and a decoupling arrangement (100) comprising a periodic structure configured on the panel to counteract nearfield coupling between the Rx array and the Tx array.

[0086] Item 2. The antenna array apparatus of item 1, wherein the periodic structure is configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path.

[0087] Item 3. The antenna array apparatus of item 1 or 2, wherein the periodic structure extends between the Rx array and the Tx array.

[0088] Item 4. The antenna array apparatus of item 3, wherein the decoupling arrangement comprises a meta surface wall (120), standing upright from the panel and comprising the periodic structure.

[0089] Item 5. The antenna array apparatus of item 4, wherein the meta surface wall comprises a plurality of cells (130) configured according to said periodic structure to create coupling paths of opposing phase between the Rx array and the Tx array.

[0090] Item 6. The antenna array apparatus of item 5, wherein the meta surface wall comprises a side strip (121) at a first side, individual patch elements (122) for each of the cells at an opposing second side, wherein each cell is configured to provide a polarization rotation function.

[0091] Item 7. The antenna array apparatus of item 6, wherein the first side of the meta surface wall, configured on one of the arrays (13, 14) is directed away from the other one of the arrays.

[0092] Item 8. The antenna array apparatus of item 6 or 7, wherein a middle layer (124) of each cell comprises an aperture grid forming a lattice which toggles orthogonally between the cells according to the periodic structure.

[0093] Item 9. The antenna array apparatus of item 8, wherein the middle layer comprises dielectric members (125, 126) separating the aperture grid from the side strip and the individual patch elements.

[0094] Item 10. The antenna array apparatus of any of items 4-9, wherein said antenna elements are configured to operate at a predetermined radio frequency, and wherein said meta surface wall projects less than 1 / 3 of a wavelength of said predetermined radio frequency.

[0095] Item 11. The antenna array apparatus of any of items 4-10, wherein said meta surface wall comprises a plurality of wall members at each of the subsets of antenna elements, comprising wall members extending between columns of said antenna elements.

[0096] Item 12. The antenna array apparatus of item 11, wherein said wall members extend parallel to a border line between the Rx array and the Tx array.

[0097] Item 13. The antenna array apparatus of item 11 or 12, wherein said wall members encompass each of the antenna elements.

[0098] Item 14. The antenna array apparatus of any preceding item, comprising a control unit (20) arranged to selectively configure the antenna elements to form part of one of the Rx array or the Tx array.

[0099] Item 15. The antenna array apparatus of any of items 1-3, wherein the decoupling arrangement comprises a capacitive strip (110) on the panel, wherein the capacitive strip is divided in segments (111) configured according to said periodic structure.

[0100] Item 16. The antenna array apparatus of item 15, wherein each segment extends alongside two adjacent antenna elements, and wherein a gap (112) between successive segments is formed at each antenna element. Item 17. The antenna array apparatus of item 15 or 16, wherein each segment comprises a plurality of separate and parallel sub-strips (113), extending within said capacitive strip.

[0101] Item 18. The antenna array apparatus of any of items 15-17, wherein a first capacitive strip extends around the Tx array and a second capacitive strip extends around the Rx array.

[0102] Item 19. The antenna array apparatus of item 1, wherein the decoupling arrangement comprises a plurality of parasitic elements (101, 102) on the panel, configured to obtain a lateral separation of phase centers of the Tx array and the Rx array.

[0103] Item 20. The antenna array apparatus of item 19, wherein said Rx array and the Tx array are arranged adjacent to each other, and wherein the parasitic elements comprise parasitic patches (101) arranged outwardly of the Rx array and the Tx array.

[0104] Item 21. The antenna array apparatus of item 20, wherein the parasitic elements comprise parasitic strips (102) extending parallel to a borderline between the Rx array and the Tx array, each parasitic strip extending adjacent one column of antenna elements and one parasitic patch on each side outwardly of said one column.

[0105] Item 22. The antenna array apparatus of any of items 19-21, comprising a control unit (20) arranged to selectively configure the antenna elements to form part of one of the Rx array or the Tx array.

[0106] Item 23. The antenna array apparatus of any preceding item, wherein said panel comprises a first subpanel carrying the Rx array, and a second subpanel carrying the Tx array, wherein the first and second subpanels are arranged adjacent to each other in a substantially common plane.

[0107] Item 24. The antenna array apparatus of any preceding item, further comprising an amplifier unit (12) connecting the Rx array with the Tx array.

Claims

CLAIMS1. An antenna array apparatus (1) with duplex architecture, comprising: a plurality of antenna elements (11) arranged in a planar configuration on a panel (10), wherein the plurality of antenna elements comprises a first subset of antenna elements defining a receiver, Rx, array (13), and a second subset of antenna elements defining a transmitter, Tx, array (14); and a decoupling arrangement (100) comprising a periodic structure configured on the panel to counteract nearfield coupling between the Rx array and the Tx array.

2. The antenna array apparatus of claim 1, wherein the periodic structure is configured to obtain opposite phase cancellation between coupling components over a first coupling path and a second coupling path.

3. The antenna array apparatus of claim 1 or 2, wherein the periodic structure extends between the Rx array and the Tx array.

4. The antenna array apparatus of claim 3, wherein the decoupling arrangement comprises a meta surface wall (120), standing upright from the panel and comprising the periodic structure.

5. The antenna array apparatus of claim 4, wherein the meta surface wall comprises a plurality of cells (130) configured according to said periodic structure to create coupling paths of opposing phase between the Rx array and the Tx array.

6. The antenna array apparatus of claim 5, wherein the meta surface wall comprises a side strip (121) at a first side, individual patch elements (122) for each of the cells at an opposing second side, wherein each cell is configured to provide a polarization rotation function.

7. The antenna array apparatus of claim 6, wherein the first side of the meta surface wall, configured on one of the arrays (13, 14) is directed away from the other one of the arrays.

8. The antenna array apparatus of claim 6 or 7, wherein a middle layer (124) of each cell comprises an aperture grid forming a lattice which toggles orthogonally between the cells according to the periodic structure.

9. The antenna array apparatus of claim 8, wherein the middle layer comprises dielectric members (125, 126) separating the aperture grid from the side strip and the individual patch elements.

10. The antenna array apparatus of any of claims 4-9, wherein said antenna elements are configured to operate at a predetermined radio frequency, and wherein said meta surface wall projects less than 1 / 3 of a wavelength of said predetermined radio frequency.

11. The antenna array apparatus of any of claims 4-10, wherein said meta surface wall comprises a plurality of wall members at each of the subsets of antenna elements, comprising wall members extending between columns of said antenna elements.

12. The antenna array apparatus of claim 11, wherein said wall members extend parallel to a border line between the Rx array and the Tx array.

13. The antenna array apparatus of claim 11 or 12, wherein said wall members encompass each of the antenna elements.

14. The antenna array apparatus of any preceding claim, comprising a control unit (20) arranged to selectively configure the antenna elements to form part of one of the Rx array or the Tx array.

15. The antenna array apparatus of any of claims 1-3, wherein the decoupling arrangement comprises a capacitive strip (110) on the panel, wherein the capacitive strip is divided in segments (111) configured according to said periodic structure.

16. The antenna array apparatus of claim 15, wherein each segment extends alongside two adjacent antenna elements, and wherein a gap (112) between successive segments is formed at each antenna element.

17. The antenna array apparatus of claim 15 or 16, wherein each segment comprises a plurality of separate and parallel sub-strips (113), extending within said capacitive strip.

18. The antenna array apparatus of any of claims 15-17, wherein a first capacitive strip extends around the Tx array and a second capacitive strip extends around the Rx array.

19. The antenna array apparatus of claim 1, wherein the decoupling arrangement comprises a plurality of parasitic elements (101, 102) on the panel, configured to obtain a lateral separation of phase centers of the Tx array and the Rx array.

20. The antenna array apparatus of claim 19, wherein said Rx array and the Tx array are arranged adjacent to each other, and wherein the parasitic elements comprise parasitic patches (101) arranged outwardly of the Rx array and the Tx array.

21. The antenna array apparatus of claim 20, wherein the parasitic elements comprise parasitic strips (102) extending parallel to a borderline between the Rx array and the Tx array, each parasitic strip extending adjacent one column of antenna elements and one parasitic patch on each side outwardly of said one column.

22. The antenna array apparatus of any of claims 19-21, comprising a control unit (20) arranged to selectively configure the antenna elements to form part of one of the Rx array or the Tx array.

23. The antenna array apparatus of any preceding claim, wherein said panel comprises a first subpanel carrying the Rx array, and a second subpanel carrying the Tx array, wherein the first and second subpanels are arranged adjacent to each other in a substantially common plane.

24. The antenna array apparatus of any preceding claim, further comprising an amplifier unit (12) connecting the Rx array with the Tx array.5

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