Array antenna cell

Abstract

Array antenna cell. Array antenna cell (105) comprising: – a semiconductor substrate (201); – a first polarizer (207a) located on one side of the semiconductor substrate; – a second polarizer (207b) 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 (201) and the second polarizer (207b), said at least one radiating element (203) having a generally annular shape. Figure for the abbreviation: Fig. 2A

Description

Title of the invention: Array antenna cell technical field

[0001] This description relates generally to electronic devices. This description relates in particular to radio antennas, more specifically to array antennas and especially to the cells composing these arrays. Previous technique

[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 have the advantage of allowing precise control of the beam orientation emitted by the antenna and providing 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 power consumption and production costs that are too high for integration into consumer devices, and reconfigurable metasurfaces suffer from excessive losses and relatively low bandwidth.

[0004] Transmitting array or reflector 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. Summary of the invention

[0006] There is a need to overcome all or part 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 allowing for improved phase quantization in both transmission and reflection.

[0007] For this purpose, one embodiment provides for an array 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 part, the second and third part, the third and fourth part, as well as the fourth and first part.

[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] According to 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 interconnection 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 exclusively annular shape.

[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. Brief description of the drawings

[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 accompanying figures, among which:

[0031] [Fig.1] is a schematic and partial side view of an example of an array antenna of the type to which, by way of example, described embodiments apply;

[0032] [Fig.2A] is a top view of an array antenna cell of [Fig.1];

[0033] [Fig. 2B] is a schematic and partial cross-sectional view of an antenna cell network according to the embodiment of [Fig.2A];

[0034] [Fig.2C] is a schematic and partial cross-sectional view of an array antenna cell according to the embodiment of [Fig.2A];

[0035] [Fig.3A] and [Fig.3B] are schematic and partial top views of the cell in [Fig.2A];

[0036] [Fig.4] represents, in top view, several configurations of an element of the array antenna cell according to one embodiment;

[0037] [Fig.5] represents graphs of magnitudes and phase shift as a function of frequency;

[0038] [Fig.6] schematically represents different configurations of the network of [Fig.1];

[0039] [Fig.7] represents amplitude graphs (gain in dBi) as a function of an orientation angle and at a fixed frequency. Description of the implementation methods

[0040] The same elements have been designated by the same reference numerals in the different figures. In particular, the 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.

[0041] For the sake of clarity, only the steps and elements useful 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 beam of generally conical shape 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.

[0042] Furthermore, the manufacturing processes for the described transmitting or reflecting networks will not be detailed, as the production of the described structures is within the reach of a person skilled in the art using the information in this description, for example by implementing standard printed circuit board manufacturing techniques.

[0043] Unless otherwise specified, when referring to two elements connected together, this means directly connected without intermediate elements other than conductors, and when referring to two elements coupled together, this means that these two elements can be connected or linked through one or more other elements.

[0044] In the following description, when reference is made to absolute position qualifiers, such as the terms "front", "back", "top", "bottom", "left", "right", etc., or relative position qualifiers, such as the terms "above", "below", "superior", "inferior", etc., or to orientation qualifiers, such as the terms "horizontal", "vertical", etc., reference is made, unless otherwise specified, to the orientation of the figures.

[0045] Unless otherwise specified, the expressions "approximately", "about", "substantially", and "in the order of" mean within 10%, preferably within 5%.

[0046] In the following description, the terms "insulating" and "conducting" mean, unless otherwise specified, electrically insulating and electrically conductive respectively.

[0047] 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 or reflector array antennas are, for example, fabricated on a PCB (Printed Circuit Board) or CMOS (Complementary Metal-Oxide-Semiconductor) substrate. Furthermore, each elementary cell of a reconfigurable transmitter or reflector array antenna includes, for example, at least one switch, such as a PIN diode switch or a switch based on a phase-change material. Transmitter and reflector array antennas have the advantage, compared to phased array antennas and reconfigurable metasurfaces, of offering better efficiency, a wider bandwidth, and / or lower production costs. However, antennas... Existing transmitter or reflector networks suffer from various disadvantages, such as high transmission losses, excessively narrow transmission and / or reception bands, significant implementation complexity, etc.

[0048] Fig. 1 is a schematic and partial side view of an example of a transmitting array antenna 100 of the type to which, by way of example, described embodiments apply.

[0049] 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 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 along 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.

[0050] Each cell 105 is capable, in transmission, of receiving electromagnetic radiation on its first antenna element 105a and of re-emitting this radiation from its second antenna element 105b, for example by introducing a known phase shift. In reception, each cell 105 is capable of receiving electromagnetic radiation on its second antenna element 105b and of re-emitting this radiation from its first antenna element 105a with the same phase shift.

[0051] The characteristics of the beam produced by the antenna 100, in particular its shape (or template) and its maximum emission direction (or pointing direction ^o, ^o), depend on the values ​​of the phase shifts respectively introduced by the different cells 105 of the network 103. Amplitude control can also be exercised, by each elementary cell, on the incident electromagnetic wave.

[0052] The incident electromagnetic wave is, in the example of 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. The phase compensation Wmn within each cell 105 with coordinates xnm, ymn can be expressed according to the formulas below:

[0053] [Math.l] lPmn^^sp- T(sin(tf0)cos(ç^^ sin()sin(^0)ywJ

[0054] [Math.2] ^Psp “ ^mn ~ i

[0055] being the spatial delay, k being the wave number, r mn being the distance between the source and cell.

[0056] Transmitter or reflector array antennas have the advantages, among others, of exhibiting good energy efficiency and being relatively simple, inexpensive, and compact. This stems in particular from the fact that the transmitting or receiving arrays can be manufactured using planar technology, generally on a printed circuit board.

[0057] This description relates more specifically to reconfigurable array antennas 103, allowing the array 103 to be used in transmitter mode (solid arrows) or reflector mode (dashed arrows). The array 103 is said to be reconfigurable when the elementary cells 105 can be individually controlled electronically to modify their phase shift value. This makes it possible to dynamically modify the characteristics of the beam generated by the antenna, and in particular to change its pointing direction without mechanically moving the antenna or any part of the antenna by means of a motorized element.

[0058] Reconfigurable antennas use PIN (Positive Intrinsic Negative) diodes, coupled or not with patch antennas, to change configuration when using frequencies below ten gigahertz. However, some of these solutions only work in transmission or reflection, or they are unusable 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.

[0059] 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 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.

[0060] Unlike cases where the radiating element has a conductive part arranged along a diagonal of a circle, which only function in transmission, The described embodiments allow alternation between transmission phase states and reflection phase states.

[0061] This allows, for example, a two-state phase quantization in transmission and a four-state phase quantization in reflection.

[0062] Figure 2A is a top view of an antenna cell 105 with an array of Figure 1.

[0063] 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, in order to better distinguish the radiating element 203.

[0064] In the example shown, the radiating element 203 has a generally annular shape. In other words, this means that the radiating element 203 is in the form of a ring, continuous or discontinuous, and that it does not include any branch extending perpendicularly from the periphery of the ring towards the interior of the ring. That is to say, the radiating element 203 does not have a "T"-shaped structure with the bottom of the "T" pointing towards the center of the ring. The ring in [Fig. 2A] does not include any conductive structure, continuous or discontinuous, that extends predominantly along one of these radii or along one of these diameters. The radiating element 203 is, in other words, in the form of a continuous or discontinuous ring.

[0065] In the example shown, the ring is circular in shape, but in other examples it may be oval, square or rectangular in shape, or in the form of a quadrilateral, or be slightly deformed by the manufacturing processes.

[0066] In the example shown, the radiating element 203 comprises first, second, third, and fourth parts 203-1, 203-2, 203-3, 203-4, which are distinct, i.e., disjoint from one another. In the example shown, the first, second, third, and fourth parts 203-1, 203-2, 203-3, 203-4 are of the same dimensions, i.e., they could be stacked identically, apart from manufacturing variations. This allows for the integration of switches and the dynamic modification of the structure's impedance with a defined resolution.

[0067] 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.

[0068] In this example, each of the first, second, third, and fourth parts 203-1, 203-2, 203-3, 203-4 has, in top view, the same ring arc shape, in other words, a truncated ring. None of these parts includes a branch of which The elongation direction is directed towards the center of the ring, for example. This allows the cell to be used in 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 through electromagnetic excitation along the direction of this diagonal. The use of this type of radiating element with a diagonal track, coupled with orthogonal polarizers, does not allow for reflection but only for transmission.

[0069] 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.

[0070] When one of the switches is in the conducting state, the parts to which it is connected become electrically connected, which amounts to increasing the arc length of the ring; in other words, it amounts to increasing the non-discontinuous arc length of the ring. Such an architecture makes it possible to obtain reconfigurable cells adapted to switch between at least two phase states in transmission and four phase states in reflection.

[0071] In an example not shown, not all the switches are present and some of the adjacent parts are not connected to each other by a switch.

[0072] The switches SI, S2, S3 and S4 are preferably controlled substantially simultaneously in opening or closing.

[0073] 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 makes it possible to obtain phases with a constant phase difference between them and to maximize the transmission or reflection of the electromagnetic wave.

[0074] In [Fig. 2A], a cutting plane BB, perpendicular to the radiating element 203, passes through an axis of symmetry of parts 203-4 and 203-2. In addition, another cutting plane CC, perpendicular to the radiating element 203, passes through the center of switches SI and S3, in other words, through the center of the gap 231 separating the parts surrounding switches SI and S3. The plane CC is, for example, oriented at 135° with respect to the plane BB, the angles being measured in the trigonometric direction.

[0075] The line DI joining the spacing between parts 203-1 and 203-2 and the spacing between parts 203-3 and 203-4 describes, for example, an angle of 45° with respect to plane BB. The line D2 joining the spacing between parts 203-1 and 203-4 and the spacing between parts 203-3 and 203-2 (in other words, the line common to the plane CC and to the horizontal plane), describes for example an angle of 135° with respect to the BB plane.

[0076] In one example, the first, second, third and fourth switches SI, S4, S3, S2, are formed in the semiconductor substrate.

[0077] For example, the switches SI, S2, S3, S4 are MOS type transistors, PCM (Phase change memory switch) or varactors, etc.

[0078] 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 comprising carbon nanotubes or graphene, or even a doped metal oxide such as tin oxide or zinc oxide.

[0079] 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 pm.

[0080] In one example, parts 203-1, 203-2, 203-3, 203-4 have a width between an inner radius of the ring Rin and an outer radius of the ring Rout. Rin and Rout are, for example, between 135 pm and 175 pm.

[0081] In one example, the thickness of the parts of the radiating element 203 is between 30 and 150 pm, for example 35 pm.

[0082] [Fig. 2B] is a schematic and partial cross-sectional view of an array antenna cell according to the embodiment of [Fig. 2A]. More particularly, [Fig. 2B] represents the view along the section plane BB.

[0083] 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, for example, silicon. The semiconductor substrate 201 is, for example, of the CMOS type (Complementary Metal-Oxide-Semiconductor). In this case, the substrate 201 comprises, 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, an IILV semiconductor material such as gallium nitride (GaN) or gallium arsenide (GaAs). In one example, the substrate 201 is made of quartz.

[0084] 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 [Fig. 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 pm. 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 in [Fig. 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.

[0085] The portions of the radiating element 203 are formed in at least one of the conductive layers of the interconnect stack 204. In the illustrated example, portions 203-1, 203-2, 203-3, and 203-4 of the radiating element 203 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 portions 203-1, 203-2, 203-3, and 203-4 of the radiating element 203 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.

[0086] Furthermore, although [Fig. 2B] 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, as one of the parts of the radiating element 203 may, alternatively, be formed in a metallization level different from that in which the other radiating element is formed. By way of 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 level lower metallization interposed between substrate 201 and the last level of metallization.

[0087] Parts 203-1, 203-2, 203-3 and 203-4 of the radiating element 203 are, for example, of the "on-chip antenna" type.

[0088] 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 [Fig. 2B]) opposite the face 201b. The insulating region 205a is, for example, more precisely located on and in contact with the face 201a of the substrate 201.

[0089] 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 more precisely located on and in contact with the upper face of the interconnect stack 204. In the illustrated example where the last metallization level 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 level 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 level of the stack 204.

[0090] By way of example, the substrate 201 and the interconnect stack 204 form an integrated circuit chip, for example more precisely a CMOS type integrated circuit chip.

[0091] The insulating regions 205a and 205b are, for example, each made of a material having a relative dielectric permittivity er, 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 may be made of quartz, fused silica, etc. By way of example, each insulating region 205a, 205b has a thickness between 100 and 300 µm.

[0092] 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 the face 201a of the semiconductor substrate 201. In the example shown, the polarizer 207a covers a face of the insulating region 205a opposite to the semiconductor substrate 201 (the lower face of the insulating region 205a, in the orientation of [Fig.2B]).

[0093] 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 one face of the insulating region 205b opposite the semiconductor substrate 201 (the top face of the insulating region 205b, in the orientation of [Fig.2B]).

[0094] By way of example, the 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 example, to a case where the polarizer 207a is positioned opposite the primary source 101 and where the polarizer 207b is directed towards the external medium, or transmitting medium, of the antenna 100. Alternatively, the polarizers 207a and 207b may respectively be part of the second and first antenna elements 105b and 105a of the elementary cell 105. This corresponds, for example, to a case where the polarizer 207a is directed towards the external medium, or transmitting medium, of the antenna 100 and where the polarizer 207b is positioned opposite the primary source 101. In any case, the polarizer located on the source side 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 comply with this constraint.

[0095] 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.

[0096] In the example shown, the switches SI, S4 are formed in the semiconductor substrate 201, for example in regions 209-1 and 209-2 of the substrate 201, symbolized in [Fig. 2B] by dashed rectangles. The switches SI, S4 are, for example, 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 [Fig. 2B] in order to avoid cluttering the drawing.

[0097] By way of example, the semiconductor substrate 201 is part of an integrated circuit chip mechanically linked 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 the region 205a.

[0098] Although [Fig. 2B] illustrates an example in which a single elementary cell is formed in and on the same substrate, 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 not shown in [Fig. 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 in the open or closed state according to the desired orientation of the beam emitted or received by the antenna 100.

[0099] By way of example, the transmitter network 103 may further include control and biasing circuits (not illustrated in [Fig.2B]) for the switches of the elementary cells 105. In general, the transmitter network 103 may 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.

[0100] [Fig. 2C] is a schematic and partial cross-sectional view of an array antenna cell 105 according to the embodiment of [Fig. 2A]. More particularly, [Fig. 2B] represents the view along the section plane CC.

[0101] In the example shown, polarizers 207a and 207b are shown as blocks for clarity.

[0102] In this example, parts 203-3 and 203-4 are represented in solid lines because they are set back from plane CC.

[0103] In the example shown, no part of the radiating element 203 is arranged in the CC plane. The same is true with cutting planes rotated 90° or 270° with respect to the CC plane. In the case of these planes rotated 90° or 270°, no part of the radiating element 203 would appear cut because no part of the radiating element extends principally along all or part of a diameter of the radiating element 203.

[0104] 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 pm, preferably about 50 pm. The spacings 231 allow for several configurations for the ring and also ensure a certain degree of electromagnetic isolation between adjacent parts of the radiating element 203.

[0105] Fig. 3A and Fig. 3B are schematic and partial top views of the cell in Fig. 2A. In particular, in Fig. 3A only element 207a is shown in transparency, the other parts of the cell not being shown for clarity.

[0106] The section plane BB of figures 2A to 2B is shown in figures 3A and 3B.

[0107] Figure 3A illustrates more precisely an example of the structure of the 207a polarizer arranged on the side of face 201a of the semiconductor substrate 201.

[0108] 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 [Fig. 3A], by a dashed square. In one example, the bands 301 have a width W2 is between 80 and 200 pm. 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 pm.

[0109] 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.

[0110] Fig. 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.

[0111] 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 WL. The bands 311 are, for example, made of a conductive material, for example, a metal such as 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.

[0112] The bands 301 have their longitudinal extension direction oriented at 90° to the longitudinal extension of the bands 311. In one 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.

[0113] When the antenna 100 is operating in transmit mode, the polarizer 207b is, for example, adapted to control the transmission, towards the external environment, of waves from the radiating element 203. The polarizer 207b allows more precisely the transmission, towards the external 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.

[0114] One advantage of the radiating element 203 is that it allows for more phase states in reflection and transmission, and therefore more precise control of the orientation of the beam emitted by the antenna 100.

[0115] Figure 4 shows, in top view, several configurations of an element of the array antenna cell according to one embodiment. More particularly, 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.

[0116] In the UC1 configuration, a first phase state in transmission is obtained when switches SI, S3 are non-conducting, and switches S4, S2 are conducting.

[0117] In the UC2 configuration, switches SI, S3 are conducting, and switches S4, S2 are non-conducting, which allows a second phase state to be obtained in transmission.

[0118] In the case of the UC1 and UC2 configurations, the radiating element takes the form of two facing semicircles separated by a non-conducting 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 the polarizers 207a and 207b, enables transmission.

[0119] The UC1 and UC2 configurations limit insertion losses while ensuring a wide bandwidth. They also allow for two different stable phase states with a relative phase difference of approximately 180° and enable phase modulation during transmission.

[0120] In the UC3 configuration, switches SI, S2, S3, and S4 are non-conducting, which allows for a first phase state to be obtained 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 the axes D2 and DL.

[0121] In the UC4 configuration, switches S1, S2 are non-conducting, and switches S4, S3 are conducting, which allows a second phase state to be obtained in reflection. In this configuration, the radiating element adopts a generally circular, or ring-like, shape, with two non-conducting gaps arranged at the intersection of the ring with axes D2 and D1 only on the upper part (in the orientation of [Fig. 4]) of the ring.

[0122] In the UC5 configuration, switches SI, S2, S3, and S4 are conducting, which allows for a third phase state to be obtained in reflection. In this configuration, the radiating element adopts a completely circular shape, or a complete ring, that is to say the ring is entirely continuous.

[0123] 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 arranged at the intersection of the ring with the D2 axis only on the upper part (in the orientation of [Fig. 4]) of the ring and at the intersection of the ring with the DI axis only on the lower part of the ring.

[0124] The UC3, UC4, UC5, and UC6 configurations allow the elementary cells to function as individual resonators, without polarization rotation, which, in conjunction with the 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 states can also be used to form a reflecting array with two phase states separated by 180°, i.e., with a 180° relative phase difference.

[0125] The UC3, UC4, UC5, and UC6 configurations also allow for limited reflection losses while ensuring a wide frequency bandwidth. Aperture efficiency is also improved.

[0126] Figure 5 shows amplitude and phase shift graphs as a function of frequency for a given cell. More specifically, Figure 5 includes a graph a) showing the magnitude in dB, as a function of frequency expressed in GHz, of the parameters SU in the UC1 and UC2 configurations, and S21 in the UC1 and UC2 configurations. Figure 5 also includes a graph b) showing the phase shift expressed in degrees (deg) for the UC1 and UC2 configurations as a function of frequency expressed in GHz. Figure 5 further includes a graph c) showing the magnitude in dB of the parameter SI1, as a function of frequency expressed in GHz, in the UC3, UC4, UC5, and UC6 configurations. Fig. 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.

[0127] 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).

[0128] In graph b) which represents the transmission modes UC1 and UC2, two phase states are obtained and their respective deviations remain relatively stable over the frequency range from a few GHz to 400 GHz.

[0129] In graph d), which represents the reflection modes, i.e. the configurations UC3, UC4, UC5, UC6, 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°.

[0130] Figure 6 schematically represents different configurations of the array shown in Figure 1. More specifically, Figure 6 comprises six representations (a), b), c), d), e), and f) showing different cell configurations in the array 103 in front view. In this example, the array has 30 by 30 cells.

[0131] In representations a), b), the network operates in transmission mode and in representations c), d), the network operates in reflection mode. In these representations 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.

[0132] In representations a), b), the network operates in transmission at frequencies of 110 and 280 GHz respectively. In representations c), d), the network operates in reflection at frequencies of 110 and 280 GHz respectively.

[0133] 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. The higher the frequency (i.e., when moving from representation a) to representation b)), the greater the number of rings and the smaller their width.

[0134] 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.

[0135] Representations d) and e) correspond to reflecting network configurations for frequencies of 110 and 280 GHz respectively using the UC3, UC4, UC5 and UC6 configurations.

[0136] 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. The higher the frequency (i.e., when moving from representation e) to representation f)), the more The number of rings increases as 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, reverts to a UC3 configuration. The subsequent rings follow the same sequence from the UC3 configuration to the UC6 configuration, and so on.

[0137] 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.

[0138] Figure 7 shows amplitude (gain in dBi) graphs as a function of angle 0 and frequency. More specifically, in graphs a) and b) of Figure 7, the dashed lines represent the 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 the 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.

[0139] In cases a) and b) of [Fig.7], the 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.

[0140] 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. Those skilled in the art can also choose the length of each part 203-1, 203-2, 203-3, and 203-4 according to the desired phase states.

[0141] Finally, the practical implementation of the described embodiments and variants is within the reach of a person skilled in the art, based on the functional indications given above. In particular, a person skilled in the art is able to plan for integration into the semiconductor substrate 201 of electronic components such as power amplifiers, control circuits, memory or processing unit enabling control of the open or closed states of the various switches of the radiating element, etc.

Claims

Demands

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 (SI); - 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 (SI, S4, S3, S2), being formed in the semiconductor substrate (201).

7. Cell (105) according to claim 6, wherein the same spacing (231) separates the first and second part, the second and third part, the third and fourth part, and the fourth and first parts.

8. Cell (105) according to any one of claims 5 to 7, 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).

9. Cell (105) according to any one of claims 1 to 8, 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.

10. Cell (105) according to any one of claims 3, or 4 to 9 in their dependence 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).

11. Cell according to any one of claims 5, or 6 to 10 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).

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

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

14. Cell (105) according to any one of claims 6, or 7 to 13 in their dependence on claim 6, wherein a second phase state in transmission is obtained when the first and third switches (SI, S3) are non-conducting, and the second and fourth switches (S4, S2) are conducting.

15. Cell (105) according to any one of claims 6, or 7 to 14 in their dependence on claim 2, wherein a first phase-reflecting state is obtained when the first, second, third, and fourth switches are non-conducting.

16. Cell (105) according to any one of claims 6, or 7 to 15 in their dependence on claim 6, wherein a second phase-reflecting state is obtained when the first, second, third, and fourth switches are conducting.

17. Cell (105) according to any one of claims 6, or 7 to 16 in their dependence on claim 6, wherein a third phase state in reflection is obtained when the first and fourth switches (SI, S2) are non-conducting, and the second and third switches (S4, S3) are conducting.

18. Cell (105) according to any one of claims 6, or 7 to 17 in their dependence on claim 6, wherein a fourth phase state in reflection is obtained when the first and second switches (SI, S4) are non-conducting, and the third and fourth switches (S3, S2) are conducting.

19. Cell (105) according to any one of claims 1 to 18, wherein the radiating element has a generally exclusively annular shape.

20. Cell (105) according to any one of claims 1 to 19, wherein the radiating element has a general circular, or oval, or general quadrilateral shape, for example square or rectangular.

21. Antenna array (103) comprising a plurality of cells (105) according to any one of claims 1 to 20.

22. Network (103) according to claim 21, wherein the semiconductor substrate (201) is common to several cells (105) of the network.

23. Antenna (100) comprising an array (103) according to claim 21 or 22 and at least one source (101) configured to irradiate one face of the array.

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