Array antenna cell

Abstract

Array antenna cell (105) comprising: - a semiconductor substrate (201); - a first polarizer (207a) located on a first side of the semiconductor substrate; - a second polarizer (207b) located on a second side of the semiconductor substrate, opposite to the first side; and - at least one radiating element (203) interposed between the semiconductor substrate (201) and the second polarizer (207b), said at least one radiating element (203) having a generally annular shape.

Description

Domaine technique

[0001] This description applies generally to electronic devices. It specifically addresses radio antennas, more precisely array antennas and, in particular, the cells that make up these arrays. Technique antérieure

[0002] In various applications, such as satellite communication systems and communication devices on 5G and 6G mobile networks, it would be desirable to have electronically steerable radio antennas, whether in transmission or reflection, operating with sub-THz frequencies, i.e., frequencies from 100 to 500 GHz.

[0003] Among the various radio antenna technologies capable of meeting the needs of applications using sub-THz frequencies, phased array antennas and reconfigurable metasurfaces based on liquid crystals or CMOS technology have been proposed. Phased array antennas offer the advantage of precise control of the beam orientation and provide access to a wide angular range. Reconfigurable metasurfaces based on liquid crystals are more compact than phased array antennas while offering similar advantages. However, phased array antennas have excessively high power consumption and production costs for integration into consumer devices, and reconfigurable metasurfaces suffer from significant losses and relatively low bandwidth.

[0004] Transmitting array or reflecting array antennas ("transmitarray antenna", "reflectarray antenna" in English) have also been proposed.

[0005] However, these antennas are not versatile or are limited when frequencies increase. Résumé de l'invention

[0006] There is a need to overcome some or all of the drawbacks of existing transmitting or reflecting array antennas. In particular, it would be desirable to have transmitting array antennas with high gain, high energy efficiency, and reduced complexity, while also enabling improved phase quantization in both transmission and reflection.

[0007] To this end, one embodiment provides for a network antenna cell comprising: a semiconductor substrate; a first polarizer located on one side of the semiconductor substrate; a second polarizer located on a second side of the semiconductor substrate, opposite the first side; and at least one radiating element interposed between the semiconductor substrate and the second polarizer, said at least one radiating element having a general annular shape.

[0008] According to one embodiment, said at least one radiating element is adapted to switch between transmission phase states and reflection phase states.

[0009] According to one embodiment, the first polarizer and the second polarizer are straight and orthogonal to each other.

[0010] According to one embodiment, the first side is a first face of the semiconductor substrate, and the second side is a second face of the semiconductor substrate.

[0011] According to one embodiment, the radiating element comprises at least a first, a second, a third, and a fourth distinct parts, of the same dimensions, and each having, in top view, the same truncated ring shape.

[0012] According to one embodiment: the first and second parts are connected by a first switch; the second and third parts are connected by a second switch; the third and fourth parts are connected by a third switch; the fourth and first parts are connected by a fourth switch; the first, second, third and fourth switches, being formed in the semiconductor substrate.

[0013] According to one embodiment, the same spacing separates the first and second parts, the second and third parts, the third and fourth parts, and the fourth and first parts.

[0014] According to one embodiment, each of the first, second, third, and fourth parts is located on, and in contact with, the second face of the semiconductor substrate.

[0015] According to one embodiment: the first polarizer comprises a plurality of first conducting bands substantially parallel to each other; and the second polarizer comprises a plurality of second conducting bands substantially parallel to each other and substantially orthogonal to the first conducting bands.

[0016] In one embodiment, the cell further comprises: a first insulating region interposed between the first face of the semiconductor substrate and the first polarizer; and a second insulating region interposed between the second face of the semiconductor substrate and the second polarizer.

[0017] According to one embodiment, the first, second, third, and fourth parts are formed in at least one metallization level of an interconnect stack interposed between the semiconductor substrate and the second polarizer.

[0018] According to one embodiment, the radiating element is adapted to switch between two phase states in transmission and four phase states in reflection.

[0019] According to one embodiment, a first phase state in transmission is obtained when the first and third switches are conducting, and the second and fourth switches are not conducting.

[0020] According to one embodiment, a second phase state in transmission is obtained when the first and third switches are non-conducting, and the second and fourth switches are conducting.

[0021] According to one embodiment, a first phase state in reflection is obtained when the first, second, third, and fourth switches are non-conducting.

[0022] According to one embodiment, a second phase state in reflection is obtained when the first, second, third, and fourth switches are conducting.

[0023] According to one embodiment, a third phase state in reflection is obtained when the first and fourth switches are non-conducting, and the second and third switches are conducting.

[0024] According to one embodiment, a fourth phase state in reflection is obtained when the first and second switches are non-conducting, and the third and fourth switches are conducting.

[0025] According to one embodiment, the radiating element has a general shape that is exclusively annular.

[0026] According to one embodiment, the radiating element has a general circular shape, or oval, or a quadrilateral shape, for example square or rectangular.

[0027] One embodiment provides for an antenna array comprising a plurality of cells as described above.

[0028] According to one embodiment, the semiconductor substrate is common to several cells of the network.

[0029] One embodiment provides an antenna comprising an array as described above and at least one source configured to irradiate one face of the array. Brève description des dessins

[0030] These features and advantages, as well as others, will be described in detail in the following description of particular embodiments, given by way of non-limiting example, in relation to the attached figures, among which: there figure 1 is a schematic and partial side view of an example of an array antenna of the type to which the described embodiments apply by way of example; the figure 2A is a top view of an array antenna cell of the figure 1 ; there figure 2B is a schematic and partial cross-sectional view of an array antenna cell according to the embodiment of the figure 2A ; there figure 2C is a schematic and partial cross-sectional view of an array antenna cell according to the embodiment of the figure 2A ; there figure 3A and the figure 3B are schematic and partial top views of the cell of the figure 2A ; there figure 4 represents, in top view, several configurations of an element of the array antenna cell according to one embodiment; the figure 5 represents graphs of magnitudes and phase shift as a function of frequency; the figure 6 represents, schematically, different configurations of the network of the figure 1 ; there figure 7 represents amplitude graphs (gain in dBi) as a function of an orientation angle and at a fixed frequency. Description des modes de réalisation

[0031] The same elements have been designated by the same reference numerals in the different figures. In particular, structural and / or functional elements common to the different embodiments may have the same reference numerals and may have identical structural, dimensional and material properties.

[0032] For clarity, only the steps and elements necessary for understanding the described embodiments have been shown and are detailed. In particular, embodiments of a transmitting and reflecting array antenna cell are described below. However, the structure and operation of the antenna's primary source(s), intended to irradiate the transmitting or reflecting array, will not be detailed, as the described embodiments are compatible with all or most known primary irradiation sources for transmitting or reflecting array antennas. By way of example, each primary source is adapted to produce a generally conical beam irradiating all or part of the transmitting or reflecting array. Each primary source includes, for example, a horn antenna. By way of example, the central axis of each primary source is substantially orthogonal to the mean plane of the array.

[0033] Furthermore, the manufacturing processes for the transmitting or reflecting networks described will not be detailed, as the construction of the described structures is within the reach of a person skilled in the art based on the indications in this description, for example by implementing standard printed circuit board manufacturing techniques.

[0034] Unless otherwise specified, when referring to two connected elements, this means directly connected without any intermediate elements other than conductors, and when referring to two coupled elements, this means that these two elements can be connected or linked through one or more other elements.

[0035] In the description that follows, when referring to absolute positional qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative positional qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientational qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0036] Unless otherwise specified, the expressions "approximately", "roughly", "about", and "on the order of" mean within 10%, preferably within 5%.

[0037] In the description that follows, the terms "insulating" and "conducting" mean, unless otherwise specified, electrically insulating and electrically conductive respectively.

[0038] Transmitting array antennas typically comprise several elementary cells, each consisting of a first antenna element irradiated by an electromagnetic field emitted by one or more focal sources, a second antenna element transmitting a modified signal outward from the antenna, and a coupling element interposed between the first and second antenna elements. Reflecting array antennas typically comprise several elementary cells, each consisting of an antenna element irradiated by an electromagnetic field emitted by one or more sources, a reflecting element, for example a ground plane, reflecting a modified signal outward from the antenna, and a coupling element between the antenna element and the reflecting element.Transmitter and reflector array antennas are fabricated on PCB (Printed Circuit Board) or CMOS (Complementary Metal-Oxide-Semiconductor) substrates. Each cell of a reconfigurable transmitter or reflector array antenna typically includes at least one switch, such as a PIN diode switch or a switch based on a phase-change material. Transmitter and reflector array antennas offer the advantage of higher efficiency, wider bandwidth, and / or lower production costs compared to phased array antennas and reconfigurable metasurfaces.However, existing transmitting or reflecting array antennas suffer from various disadvantages, such as high transmission losses, excessively narrow transmission and / or reception bands, significant manufacturing complexity, etc.

[0039] There figure 1 is a schematic and partial side view of an example of a 100 transmitting array antenna of the type to which the described embodiments apply by way of example.

[0040] The antenna 100 typically comprises one or more primary sources 101 (a single source 101 in the example shown), positioned at a focal distance F, radiating from a transmitting or reflecting array 103. The source 101 may have any polarization, for example, linear or circular. The array 103 comprises a plurality of elementary cells 105, for example, arranged in a matrix of rows and columns. Each cell 105 typically comprises a first antenna element 105a, located on the side of a first face of the array 103 facing the primary source 101, and a second antenna element 105b, located on the side of a second face of the array opposite the first face. The second face of the array 103 is, for example, directed towards a medium for the transmission of the antenna 100.

[0041] Each cell 105 is capable, in transmission mode, of receiving electromagnetic radiation on its first antenna element 105a and re-emitting this radiation from its second antenna element 105b, for example by introducing a known phase shift. In reception mode, each cell 105 is capable of receiving electromagnetic radiation on its second antenna element 105b and re-emitting this radiation from its first antenna element 105a with the same phase shift.

[0042] The characteristics of the beam produced by antenna 100, in particular its shape (or template) and its maximum emission direction (or pointing direction) θ 0, φ 0 ), depend on the values ​​of the phase shifts respectively introduced by the different cells 105 of the network 103. An amplitude control can also be exerted, by each elementary cell, on the incident electromagnetic wave.

[0043] The incident electromagnetic wave is, in the example of the figure 1 spherical in shape. Each cell receives the incident wave with a different delay because the path differs between the source and each cell. Phase compensation ψ mn within each cell 105 of coordinates x mn , y mn can be expressed using the formulas below: ψ mn = Δ φ sp − 2 π λ sin θ 0 cos φ 0 x mn + sin θ 0 sin φ 0 y mn Δ φ sp = kr mn = 2 π λ x mn 2 + y mn 2 + F 2

[0044] Δ φ sp where k is the spatial delay, and k is the wave number, r mn being the distance between the source and the cell.

[0045] Transmitter or reflector array antennas have the advantage, among others, of exhibiting good energy efficiency and d'être They are relatively simple, inexpensive, and compact. This is mainly due to the fact that the transmitting and receiving networks can be built using planar technology, generally on printed circuit boards.

[0046] This description focuses more specifically on reconfigurable 103 array antennas, allowing the 103 array to be used in transmitter mode (solid arrows) or reflector mode (dashed arrows). The 103 array is considered reconfigurable when the individual 105 elementary cells can be electronically controlled to modify their phase shift value. This allows for dynamic modification of the characteristics of the beam generated by l'antenne, and in particular to change its pointing direction without mechanically moving the antenna or part of the antenna by means of a motorized element.

[0047] Reconfigurable antennas use PIN diodes (of l'anglais Positive Intrinsic Negative (PIN) diodes, coupled or not with patch antennas, can be used to change configurations when operating at frequencies below ten gigahertz. However, some of these solutions only work in transmission or reflection, or they are unsuitable for sub-THz frequencies because the size of the PIN diodes in this case is on the order of millimeters, which is incompatible with the wavelengths used. Such solutions also suffer from instability in reflection due to the use of two resonant modes. Finally, these solutions offer only phase quantization limited to two states in reflection or transmission. They also suffer from limited aperture efficiency and a narrow bandwidth.

[0048] To overcome these drawbacks, the embodiments provide for the use of one or more array antenna cells comprising: a semiconductor substrate; a first polarizer located on a first side of the semiconductor substrate; a second polarizer located on a second side of the semiconductor substrate, opposite to the first side; and at least one radiating element interposed between the semiconductor substrate and the second polarizer, said at least one radiating element having a general annular shape.

[0049] Unlike cases where the radiating element has a conductive part arranged along a diagonal of a circle, which only work in transmission, the described embodiments allow alternating between phase states in transmission and phase states in reflection.

[0050] This allows, for example, two-state phase quantization in transmission and four-state phase quantization in reflection.

[0051] There figure 2A is a top view of a 105 array antenna cell of the figure 1 .

[0052] In this example, the antenna cell 105 comprises a semiconductor substrate, a first polarizer located on one side of the semiconductor substrate, a second polarizer located on a second side of the semiconductor substrate, opposite the first side; and at least one radiating element 203 interposed between the semiconductor substrate and the second polarizer. In the example shown, the polarizers and the semiconductor substrate are rendered transparent for clarity, allowing the radiating element 203 to be more easily distinguished.

[0053] In the example shown, the radiating element 203 has a general annular shape. In other words, this means that the radiating element 203 is in the form of a ring, continuous or not, and that it does not include any branches extending perpendicularly from the periphery of the ring towards the interior. That is to say, the radiating element 203 does not have a "T"-shaped structure where the bottom of the "T" points towards the center of the ring. The ring of the figure 2A does not include a conductive structure, continuous or not, that extends predominantly along one of these radii or diameters. The radiating element 203 is, in other words, in the form of a continuous or discontinuous ring.

[0054] In the example shown, the ring is circular in shape, but in other examples it may be oval, square or rectangular, or in the form of a quadrilateral, or be slightly deformed by the manufacturing processes.

[0055] In the example shown, the radiating element 203 comprises a first, second, third, and fourth part 203-1, 203-2, 203-3, and 203-4, which are distinct, meaning they are separate from one another. In the example shown, the first, second, third, and fourth parts 203-1, 203-2, 203-3, and 203-4 are of the same dimensions; that is, they could be stacked identically, except for manufacturing variations. This allows for the integration of switches and the dynamic modification of the structure's impedance with a defined resolution.

[0056] In the example shown, parts 203-1 and 203-3 are diametrically opposite with respect to the center of the ring described by the radiating element 203. Similarly, parts 203-2 and 203-4 are diametrically opposite.

[0057] In this example, each of the first, second, third, and fourth parts (203-1, 203-2, 203-3, 203-4) has, when viewed from above, the same ring arc shape, in other words, a truncated ring. None of these parts includes a branch whose elongation direction is directed towards the center of the ring, for example. This allows the cell to be used in either transmission or reflection. Indeed, if the radiating element included a conductive track extending along a diagonal of the ring, for example, in a "T" shape, then this diagonal track of the radiating element would act as a polarization rotator by electromagnetic excitation along the direction of this diagonal. The use of this type of radiating element with a diagonal track, coupled with mutually orthogonal polarizers, does not allow for reflection but only for transmission.

[0058] In the example shown, parts 203-4, 203-1 are connected by a first switch S1, parts 203-1, 203-2 are connected by a second switch S4, parts 203-2, 203-3 are connected by a third switch S3, finally parts 203-3, 203-4 are connected by a fourth switch S2.

[0059] When one of the switches is in the conducting state, the parts to which it is connected become electrically connected, which increases the arc length of the ring; in other words, it increases the continuous arc length of the ring. Such an architecture allows for reconfigurable cells capable of switching between at least two phase states in transmission and four phase states in reflection.

[0060] In an unshown example, not all switches are present and some of the adjacent parts are not connected to each other by a switch.

[0061] The switches S1, S2, S3 and S4 are preferably controlled in a substantially simultaneous manner in opening or closing.

[0062] In one example, the same spacing 231, that is, a spacing of the same magnitude, separates parts 203-1 and 203-2, parts 203-2 and 203-3, parts 203-3 and 203-4, as well as parts 203-4 and 203-1. In other words, parts 203-1, 203-2, 203-3, and 203-4 are distributed homogeneously along the periphery of the ring. This allows for phases with a constant phase difference between them and maximizes the transmission or reflection of the electromagnetic wave.

[0063] In the figure 2A A cutting plane BB, perpendicular to the radiating element 203, passes through an axis of symmetry of parts 203-4 and 203-2. Furthermore, another cutting plane CC, perpendicular to the radiating element 203, passes through the center of switches S1 and S3, that is, through the center of the gap 231 separating the parts surrounding switches S1 and S3. Plane CC is, for example, oriented at 135° with respect to plane BB, the angles being measured in the counterclockwise direction.

[0064] The line D1 joining the gap between parts 203-1 and 203-2 and the gap between parts 203-3 and 203-4 describes, for example, an angle of 45° with respect to plane BB. The line D2 joining the gap between parts 203-1 and 203-4 and the gap between parts 203-3 and 203-2 (in other words, the line common to plane CC and the horizontal plane), describes, for example, an angle of 135° with respect to plane BB.

[0065] In one example, the first, second, third and fourth switches S1, S4, S3, S2, are formed in the semiconductor substrate.

[0066] For example, switches S1, S2, S3, S4 are MOS type transistors, PCM (Phase change memory switch) or varactors, etc.

[0067] In one example, the first, second, third, and fourth parts 203-1, 203-2, 203-3, 203-4, are formed in an electrically conductive material, such as a metal, for example copper, or a metallic alloy, or a conductive organic material or one comprising carbon nanotubes or graphene, or even a doped metal oxide such as tin oxide or zinc oxide.

[0068] In one example, the thickness of the first, second, third, and fourth parts 203-1, 203-2, 203-3, 203-4 is between 15 and 100 µm.

[0069] In one example, parts 203-1, 203-2, 203-3, 203-4 have a width between an inner radius of the Rin ring and an outer radius of the Rout ring. Rin and Rout are, for example, between 135 µm and 175 µm.

[0070] In one example, the thickness of the parts of the radiating element 203 is between 30 and 150 µm, for example 35 µm.

[0071] There figure 2B is a schematic and partial cross-sectional view of an array antenna cell according to the embodiment of the figure 2A More specifically, the figure 2B represents the view according to the BB section plane.

[0072] In the example shown, the elementary cell 105 comprises the semiconductor substrate 201. The substrate 201 is, for example, a wafer or a piece of wafer made of a semiconductor material, such as silicon. The semiconductor substrate 201 is, for example, of the CMOS type (Complementary Metal-Oxide-Semiconductor). In this case, the substrate 201 includes, for example, one or more electronic components made using CMOS technology, for example, at least one MOS transistor (Metal-Oxide-Semiconductor). Alternatively, the substrate 201 may be made of a semiconductor material other than silicon, for example, a III-V semiconductor material such as gallium nitride (GaN) or gallium arsenide (GaAs). In one example, the substrate 201 is made of quartz.

[0073] In the illustrated example, the elementary cell 105 comprises the radiating element 203 with its parts shown 203-1, 203-2, and 203-2 located on the semiconductor substrate 201. In this example, the parts of the radiating element are more precisely formed in a stack or interconnecting network 204 located on and in contact with a face 201b of the substrate 201 (the upper face of the substrate 201, in the orientation of the figure 2B In the example shown, the interconnect stack 204 comprises a stack of alternating conductive and insulating layers. For example, the insulating layers are made of silicon dioxide (SiO₂) and have a thickness of approximately 4 µm. The portions of parts 203-1, 203-2, and 203-4 of the radiating element 203 that are intersected by plane BB are represented by dashed rectangles, and the portions set back from this plane BB are represented by solid lines. figure 2B Parts 203-1, 203-2, 203-3, and 203-4 of the radiating element 203 are, for example, metallic layers, also called metallization levels. Although not detailed in the drawings, the interconnect stack 204 includes, for example, in addition to parts 203-1, 203-2, 203-3, and 203-4 of the radiating element 203, conductive tracks formed in the conductive layers and conductive vias, for example, metallic vias, interconnecting conductive tracks located in different conductive layers.

[0074] The radiating elements 203 are formed in at least one of the conductive layers of the interconnect stack 204. In the illustrated example, the radiating elements 203-1, 203-2, 203-3, and 203-4 are formed in a single metallization level, for example, in the upper metallization level, also called the last metallization level, i.e., the metallization level furthest from the semiconductor substrate 201. This example is not, however, limiting, and the radiating elements 203-1, 203-2, 203-3, and 203-4 may, alternatively, be formed in a metallization level other than the last metallization level and / or in several metallization levels of the stack 204. Furthermore, in the example shown, the upper metallization level is coated with an insulating layer of stack 204.This example is not limiting, however, the upper level of metallization could, as an alternative, be flush with the top face of the stack 204.

[0075] Furthermore, although the figure 2B This illustrates a case in which the parts of the radiating element 203 are made in the same metallization level of the interconnecting stack 204. This example is not limiting; alternatively, one of the parts of the radiating element 203 may be formed in a different metallization level than the other radiating element. For example, parts 203-1 and 203-3 of the radiating element 203 are made in a first metallization level of the stack 204, for example, the upper metallization level, and parts 203-2 and 203-4 of the radiating element 203 are made in a second metallization level separated from the first metallization level by one of the insulating layers of the stack 204, for example, a lower metallization level interposed between the substrate 201 and the last metallization level.

[0076] Parts 203-1, 203-2, 203-3 and 203-4 of the radiating element 203 are, for example, of the "on-chip antenna" type.

[0077] In the illustrated example, the elementary cell 105 further comprises insulating regions 205a and 205b located on either side of the semiconductor substrate 201. In this example, the insulating region 205a covers a face 201a of the semiconductor substrate 201 (the lower face of the substrate 201, in the orientation of the figure 2B ) opposite face 201b. The insulating region 205a is, for example, more precisely located on and in contact with face 201a of substrate 201.

[0078] In the example shown, the insulating region 205b is located on the substrate 201 and the portions 203-1, 203-2, 203-3, and 203-4 of the radiating element 203. In this example, the insulating region 205b is specifically located on and in contact with the upper face of the interconnect stack 204. In the example shown where the last metallization layer is coated with an insulating layer, the insulating region 205b is located on and in contact with this insulating layer. In the case where the last metallization layer is flush with the upper face of the interconnect stack 204, the insulating region 205b is located on and in contact with the last metallization layer of the stack 204.

[0079] As an example, the substrate 201 and the interconnect stack 204 form an integrated circuit chip, for example more precisely a CMOS type integrated circuit chip.

[0080] The insulating regions 205a and 205b are, for example, each made of a material with a relative dielectric permittivity εr, also called the "dielectric constant," between 2 and 4. The insulating regions 205a and 205b are, for example, formed in one or more insulating layers of a printed circuit board. Alternatively, each insulating region 205a, 205b can be made of quartz, fused silica, etc. As an example, each insulating region 205a, 205b has a thickness between 100 and 300 µm.

[0081] In the illustrated example, the elementary cell 105 further comprises polarizer-type structures 207a and 207b located on either side of the semiconductor substrate 201. In this example, the polarizer 207a is located on the side of face 201a of the semiconductor substrate 201. In the example shown, the polarizer 207a covers a face of the insulating region 205a opposite the semiconductor substrate 201 (the lower face of the insulating region 205a, in the orientation of the figure 2B ).

[0082] In the example shown, the polarizer 207b is located on the side of face 201b of the semiconductor substrate 201. In this example, the polarizer 207b covers a face of the insulating region 205b opposite the semiconductor substrate 201 (the upper face of the insulating region 205b, in the orientation of the figure 2B ).

[0083] For example, polarizers 207a and 207b are respectively part of the first and second antenna elements 105a and 105b of the elementary cell 105. This corresponds, for instance, to a case where polarizer 207a is positioned opposite the primary source 101 and polarizer 207b is directed towards the external medium, or transmitting medium, of the antenna 100. Alternatively, polarizers 207a and 207b can respectively be part of the second and first antenna elements 105b and 105a of the elementary cell 105. This corresponds, for instance, to a case where polarizer 207a is directed towards the external medium, or transmitting medium, of the antenna 100 and polarizer 207b is positioned opposite the primary source 101. In any case, the polarizer located at the source end is polarized in the same direction as the source.In practice, the polarization of the wave to be transmitted or received is fixed, and the polarizers are rotated to respect this constraint.

[0084] In the case where the insulating regions 205a and 205b are formed in one or more insulating layers of a printed circuit board, the parts 203-1, 203-2, 203-3 and 203-4 and the polarizers 205a and 205b are for example formed in metallic conductive layers, also called metallization levels, of the printed circuit board.

[0085] In the example shown, the switches S1, S4 are formed in the semiconductor substrate 201, for example in regions 209-1 and 209-2 of the substrate 201 symbolized, in figure 2B , by dashed rectangles. Switches S1, S4, for example, are connected to the corresponding parts 203-1, 203-2, 203-3, 203-4 of the radiating element 203 by conductive vias and / or conductive traces of the interconnect stack 204 shown by dashed lines. These connections have not been detailed in figure 2B in order not to overload the drawing.

[0086] As an example, the semiconductor substrate 201 is part of an integrated circuit chip mechanically bonded to the printed circuit board comprising the insulating regions 205a and 205b and the polarizers 207a and 207b by techniques implemented in the mounting of surface-mount electronic components, for example by soldering or via solder balls, for example on the side of region 205a.

[0087] Although the figure 2B This illustrates an example in which a single elementary cell is formed in and on the same substrate; however, this example is not limiting. More generally, all or part of the elementary cells 105 of the transmitting network 103 can be formed in and on the same substrate. Furthermore, although this has not been shown in figure 2B Control and power supply circuits can be provided in the printed circuit board. These circuits may, for example, include shift registers, flip-flops, buffer circuits, etc., adapted to control the switches of the elementary cells 105 to the open or closed state depending on the desired orientation of the beam emitted or received by the antenna 100.

[0088] As an example, the transmitter network 103 may also include control and biasing circuits (not shown in figure 2B ) switches of the elementary cells 105. In general, the transmitting network 103 can include any number of control and biasing circuits associated with any number of sets of elementary cells, each comprising several elementary cells formed on the same semiconductor substrate.

[0089] There figure 2C is a schematic and partial cross-sectional view of a 105 array antenna cell according to the embodiment of the figure 2A More specifically, the figure 2B represents the view according to the CC cutting plane.

[0090] In the example shown, polarizers 207a and 207b are represented as blocks for clarity.

[0091] In this example, parts 203-3 and 203-4 are represented in solid lines because they are arranged indented from the CC plane.

[0092] In the example shown, no part of the radiating element 203 lies within the CC plane. The same is true for cutting planes rotated 90° or 270° with respect to the CC plane. In the case of these 90° or 270° rotated planes, no part of the radiating element 203 would appear cut because no part of the radiating element extends primarily along all or part of a diameter of the radiating element 203.

[0093] In the example shown, the spacing 231 separates the respective ends of the facing parts 203-3 and 203-4. The spacing 231 is, for example, between 10 and 100 µm, preferably around 50 µm. The spacings 231 allow for several configurations of the ring and also ensure a certain degree of electromagnetic isolation between adjacent parts of the radiating element 203.

[0094] There figure 3A and the figure 3B are schematic and partial top views of the cell of the figure 2A More specifically, in the figure 3A only element 207a is represented by transparency, the other parts of the cell are not represented for clarity.

[0095] The BB cutting plan of figures 2A à 2B is represented on the figures 3A et 3B .

[0096] There figure 3A illustrates more precisely an example of the structure of the polarizer 207a arranged on the side of the face 201a of the semiconductor substrate 201.

[0097] In the example shown, the polarizer 207a comprises a plurality of disjoint bands 301 located below and in contact with the insulating region 205a symbolized, in figure 3A , by a dashed square. In one example, the 301 strips have a width W2 between 80 and 200 µm. In this example, the 301 strips are substantially parallel to each other and have a principal elongation parallel to the BB plane. In the illustrated example, the 301 strips are spaced substantially regularly, with a constant pitch W1. In one example, W1 is equal to W2. The 301 strips are, for example, made of a conductive material, such as a metal like copper, or a metal alloy. In one example, the pitch W1 is between 80 and 200 µm.

[0098] When the antenna 100 is operating in transmit mode, the polarizer 207a is adapted to control the transmission, towards the radiating element 203, of waves from the primary source 101. The polarizer 207a allows more precisely the transmission, towards the radiating element 203, of incident waves having a polarization substantially identical to that of the polarizer 207a, that is to say a linear polarization substantially orthogonal to the bands 301, and the reflection of incident waves having a polarization different from that of the polarizer 207a, that is to say a linear polarization parallel to the bands 301.

[0099] There figure 3B illustrates in particular an example of the structure of the polarizer 207b arranged on the side of the face 201b of the semiconductor substrate 201.

[0100] In the example shown, the polarizer 207b comprises a plurality of bands 311 situated on and in contact with the insulating region 205b. In this example, the bands 311 are substantially parallel to each other and have dimensions W2 similar to those of the bands 301. The bands 311 are, for example, substantially orthogonal to the bands 301 of the polarizer 207a. In the illustrated example, the bands 311 are spaced substantially regularly, at a constant pitch, for example, the pitch W1. The bands 311 are, for example, made of a conductive material, such as a metal like copper, or a metal alloy. For the sake of simplifying the manufacture of the elementary cell 105, the bands 311 of the polarizer 207b are, for example, made of the same material as the bands 301 of the polarizer 207a.

[0101] The bands 301 have their longitudinal extension direction oriented at 90° to the longitudinal extension of the bands 311. In an example, the bands 301 and 311 have their longitudinal extension direction oriented at an angle of respectively 45° and -45° with respect to the line D2.

[0102] When the antenna 100 is operating in transmission, the polarizer 207b is, for example, suitable for controlling the transmission, towards the outside environment, of waves from the radiating element 203. The polarizer 207b allows more precisely the transmission, towards the outside environment, of incident waves having a polarization substantially identical to that of the polarizer 207b, that is to say a linear polarization substantially orthogonal to the bands 311, and the reflection of incident waves having a polarization different from that of the polarizer 207b, that is to say a linear polarization parallel to the bands 311.

[0103] One advantage of the radiating element 203 is that it allows for more phase states in reflection and transmission, thus more precise control of the orientation of the beam emitted by the antenna 100.

[0104] There figure 4 represents, in top view, several configurations of an element of the array antenna cell according to an embodiment. More specifically, the figure 4 illustrates two configurations UC1 and UC2 of the radiating element 203 used in transmission, and four configurations UC3, UC4, UC5 and UC6 used in reflection for example.

[0105] In the UC1 configuration, a first phase state in transmission is obtained when switches S1, S3 are non-conducting, and switches S4, S2 are conducting.

[0106] In the UC2 configuration, switches S1, S3 are conducting, and switches S4, S2 are not conducting, which allows a second phase state to be obtained in transmission.

[0107] In the case of configurations UC1 and UC2, the radiating element takes the form of two facing semicircles separated by a non-conductive line oriented along axis D2 and axis D1, respectively. These two semicircles act as a rotator, forming a conductive pseudo-diagonal arranged along axes D2 and D1, respectively. This pseudo-diagonal induces a polarization rotation which, in conjunction with polarizers 207a and 207b, enables transmission.

[0108] The UC1 and UC2 configurations minimize insertion losses while ensuring a wide bandwidth. They also allow for two stable, distinct phase states with a relative phase difference of approximately 180°, enabling phase modulation during transmission.

[0109] In the UC3 configuration, switches S1, S2, S3, and S4 are non-conducting, which allows for a first phase state in reflection. In this configuration, the radiating element adopts a shape comprising four ring arcs, or as represented, circular arcs, separated by non-conducting gaps arranged at the intersection of the ring with axes D2 and D1.

[0110] In the UC4 configuration, switches S1 and S2 are non-conducting, and switches S4 and S3 are conducting, thus providing a second phase state in reflection. In this configuration, the radiating element adopts a generally circular, or ring-like, shape, with two non-conducting gaps located at the intersection of the ring with axes D2 and D1 only on the upper part (in the orientation of the figure 4 ) of the ring.

[0111] In the UC5 configuration, switches S1, S2, S3, and S4 are forward-biased, resulting in a third phase state during reflection. In this configuration, the radiating element adopts a completely circular, or full-ring, shape; that is, the ring is entirely continuous.

[0112] In the UC6 configuration, the first and second switches S1, S4 are non-conducting, and switches S3, S2 are conducting, thus providing a fourth phase state in reflection. In this configuration, the radiating element adopts a generally circular shape with two non-conducting gaps located at the intersection of the ring with the D2 axis only on the upper part (in the orientation of the figure 4 ) of the ring and at the intersection of the ring with axis D1 only on the lower part of the ring.

[0113] The UC3, UC4, UC5, and UC6 configurations allow the individual cells to function as individual resonators, without polarization rotation. This, in conjunction with polarizers 207a and 207b, results in reflection of the incident wave. Depending on the configuration implemented, different modes of the incident wave are selected, resulting in four different reflected phase states. Each of the four phase states is separated by a 90° phase difference. The UC3, UC4, UC5, and UC6 configurations can also be used to form a reflecting array with two phase states separated by 180°, i.e., with a 180° relative phase difference.

[0114] The UC3, UC4, UC5, and UC6 configurations also allow for limited reflection losses while ensuring a wide frequency bandwidth. Aperture efficiency is also improved.

[0115] There figure 5 represents amplitude and phase shift graphs as a function of frequency for a given cell. More specifically, the figure 5 includes a graph a) representing the magnitude in dB, as a function of the frequency expressed in GHz, of parameters S11 in configurations UC1 and UC2, and S21 in configurations UC1 and UC2. The figure 5 also includes a graph b), representing the phase shift expressed in degrees (deg) for the UC1 and UC2 configurations as a function of the frequency expressed in GHz. The figure 5 It also includes a graph (c) representing the magnitude in dB of the parameter S11, as a function of the frequency expressed in GHz, in the UC3, UC4, UC5 and UC6 configurations. figure 5 finally includes a graph d), representing the phase shift expressed in degrees (deg) as a function of the frequency expressed in GHz for the UC3, UC4, UC5, UC6 configurations.

[0116] These graphs show that, for the W and D bands, the 1-dB bandwidth obtained is 63 GHz, or 56% at 112.5 GHz (81–144 GHz). For the H band, the 1-dB bandwidth obtained is 116 GHz, or 44.2% of 262 GHz (204–320 GHz).

[0117] In graph b) which represents the transmission modes UC1 and UC2, two phase states are obtained and their respective differences remain relatively stable over the frequency range from a few GHz to 400 GHz.

[0118] In graph d), which represents the reflection modes, i.e., the UC3, UC4, UC5, and UC6 configurations, four phase states are obtained, and the difference between them remains relatively stable over the frequency range from a few GHz to 400 GHz. The four phase states obtained are, at a given frequency, 0°, 90°, 180°, and 270°.

[0119] There figure 6 represents, schematically, different configurations of the network of the figure 1 More specifically, the figure 6 includes six representations a), b), c), d), e) and f) showing different cell configurations in the 103 array in front view. In this example, the array is 30 by 30 cells.

[0120] In diagrams a) and b), the network operates in transmission mode, and in diagrams c) and d), the network operates in reflection mode. In these diagrams a), b), c), and d), the cells shown in dark color are in the UC1 configuration, and the cells shown in light color are in the UC2 configuration.

[0121] In diagrams a) and b), the network operates in transmission mode at frequencies of 110 and 280 GHz respectively. In diagrams c) and d), the network operates in reflection mode at frequencies of 110 and 280 GHz respectively.

[0122] The cell configurations in representations a) and b) correspond to concentric rings centered on the center of the lattice. Each ring corresponds to one of UC1 or UC2 configurations. As the frequency increases (i.e., when moving from representation a) to representation b)), the number of rings increases and their width decreases.

[0123] The cell configurations in representations c) and d) are the inverse of those in representations a) and b), respectively. In other words, if in representations a) and b) a cell is in configuration UC1, then in representations c) and d) that same cell is ordered to be in configuration UC2. Conversely, if in representations a) and b) a cell is in configuration UC2, then in representations c) and d) that same cell is ordered to be in configuration UC1.

[0124] Representations d) and e) correspond to reflecting network configurations for frequencies of 110 and 280 GHz respectively using UC3, UC4, UC5 and UC6 configurations.

[0125] The cell configurations in representations e) and f) correspond to concentric rings centered on the center of the lattice. Each ring corresponds to one of the cell configurations UC3, UC4, UC5, or UC6. As the frequency increases (i.e., when moving from representation e) to representation f)), the number of rings increases and their respective widths decrease.In examples e) and f), the configurations of the different rings follow a periodic sequence: first, a ring whose cells have the UC3 configuration; then, a second adjacent ring located immediately outside the first ring has its cells configured in UC4; next, a third adjacent ring located immediately outside the second ring has its cells configured in UC5; and a fourth adjacent ring located immediately outside the third ring has its cells configured in UC6. The following ring, outside the fourth ring, returns to a UC3 configuration. The subsequent rings follow the same sequence from the UC3 configuration to the UC6 configuration, and so on.

[0126] By comparing the reflection gains between examples c) and e) or d) and f), a gain improvement of more than 10 points is obtained using the UC3, UC4, UC5, and UC6 configurations compared to using the UC1 and UC2 configurations alone. Quantization losses are thus reduced from 3 dB to 0.8 dB.

[0127] There figure 7 represents amplitude graphs (gain in dBi) as a function of the angle θ and as a function of frequency. More specifically, in graphs a) and b) of the figure 7 The dashed lines represent cases where only the UC1 and UC2 configurations are used in reflection (1-bit RA) for frequencies of 120 GHz and 300 GHz respectively. The solid lines represent cases where the UC3, UC4, UC5, and UC6 configurations are used in reflection (2-bit RA) for frequencies of 120 GHz and 300 GHz respectively.

[0128] In cases a) and b) of the figure 7The central peak has a higher amplitude for the UC3, UC4, UC5 and UC6 configurations. In addition, the amplitudes at angles beyond 10° are more attenuated when the UC3, UC4, UC5 and UC6 configurations are used.

[0129] Various embodiments and variants have been described. Those skilled in the art will understand that certain features of these various embodiments and variants could be combined, and other variants will become apparent to them. In particular, those skilled in the art can adapt the number of parts 203-1, 203-2, 203-3, and 203-4, for example, to have more than four, as well as the number of switches S1, S2, S3, and S4 of the radiating element 203, depending on the intended application. Furthermore, those skilled in the art can select the length of each part 203-1, 203-2, 203-3, and 203-4 according to the desired phase states.

[0130] Finally, the practical implementation of the described embodiments and variants is within the grasp of a person skilled in the art, based on the functional specifications given above. In particular, a person skilled in the art can plan for the integration into the semiconductor substrate 201 of electronic components such as power amplifiers, control circuits, memory, or a processing unit for controlling the open or closed states of the various switches of the radiating element, etc.

Claims

1. Array antenna cell (105) comprising: - a semiconductor substrate (201); - a first polarizer (207a) located on a first side of the semiconductor substrate; - a second polarizer (207b) located on a second side of the semiconductor substrate, opposite to the first side; and - at least one radiating element (203) interposed between the semiconductor substrate (201) and the second polarizer (207b), said at least one radiating element (203) having a generally annular shape.

2. Cell (105) according to claim 1, wherein said at least one radiating element (203) is adapted to switch between transmission phase states and reflection phase states.

3. Cell (105) according to claim 1 or 2, wherein the first polarizer (207a) and the second polarizer (207b) are straight and orthogonal to each other.

4. Cell (105) according to any one of claims 1 to 3, wherein the first side is a first face (201a) of the semiconductor substrate, and the second side is a second face (201b) of the semiconductor substrate.

5. Cell (105) according to any one of claims 1 to 4, wherein the radiating element (203) comprises at least a first, a second, a third, and a fourth part (203-1, 203-2, 203-3, 203-4) distinct, of the same dimensions, and each having, in top view, the same truncated ring shape.

6. Cell (105) according to claim 5, wherein: - the first and second parts (203-4, 203-1) are connected by a first switch (S1); - the second and third parts (203-1, 203-2) are connected by a second switch (S4); - the third and fourth parts are connected by a third switch (203-2, 203-3); - the fourth and first parts (203-3, 203-4) are connected by a fourth switch (S2); the first, second, third and fourth switches (S1, S4, S3, S2), being formed in the semiconductor substrate (201); and / or - the same spacing (231) separates the first and second parts, the second and third parts, the third and fourth parts, as well as the fourth and first parts.

7. Cell (105) according to any one of claims 5 or 6, wherein each of the first, second, third, and fourth parts (203-4, 203-1, 203-2, 203-3) is located on, and in contact with, the second face (201b) of the semiconductor substrate (201).

8. Cell (105) according to any one of claims 1 to 7, wherein: - the first polarizer (207a) comprises a plurality of first conducting bands (301) substantially parallel to each other; and - the second polarizer (207b) comprises a plurality of second conducting bands (311) substantially parallel to each other and substantially orthogonal to the first conducting bands.

9. Cell (105) according to any one of claims 3, or 4 to 8 as dependent on claim 3, further comprising: - a first insulating region (205a) interposed between the first face (201a) of the semiconductor substrate (201) and the first polarizer (207a); and - a second insulating region (205b) interposed between the second face (201b) of the semiconductor substrate and the second polarizer (207b).

10. Cell according to any one of claims 5, or 6 to 9 in their dependence on claim 5, wherein the first, second, third, and fourth parts (203-4, 203-1, 203-2, 203-3) are formed in at least one metallization level of an interconnect stack (204) interposed between the semiconductor substrate (201) and the second polarizer (207b).

11. Cell (105) according to any one of claims 2, or 3 to 10 as dependent on claim 2, wherein the radiating element (203) is adapted to switch between two phase states in transmission and four phase states in reflection.

12. Cell (105) according to any one of claims 6, or 7 to 11 in their dependence on claim 6, wherein: a first phase state in transmission is obtained when the first and third switches (S1, S3) are conducting, and the second and fourth switches (S4, S2) are not conducting; and / or a second phase state in transmission is obtained when the first and third switches (S1, S3) are not conducting, and the second and fourth switches (S4, S2) are conducting; and / or a first phase state in reflection is obtained when the first, second, third, and fourth switches are not conducting; and / or a second phase state in reflection is obtained when the first, second, third, and fourth switches are conducting;and / or a third phase state in reflection is obtained when the first and fourth switches (S1, S2) are non-conducting, and the second and third switches (S4, S3) are conducting; and / or a fourth phase state in reflection is obtained when the first and second switches (S1, S4) are non-conducting, and the third and fourth switches (S3, S2) are conducting.

13. Cell (105) according to any one of claims 1 to 12, wherein: the radiating element has a general exclusively annular shape; and / or the radiating element has a general circular, or oval, or quadrilateral shape, for example square or rectangular.

14. Antenna array (103) comprising a plurality of cells (105) according to any one of claims 1 to 13, and in which the semiconductor substrate (201) is common to several cells (105) of the array.

15. Antenna (100) comprising an array (103) according to the preceding claim and at least one source (101) configured to irradiate one face of the array.

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