Radio frequency device having an optimized radiation pattern for

Abstract

A radio frequency signal transmitting and / or receiving device (900) intended to be integrated into a motion detection system in a motor vehicle and comprising: a printed circuit (930); at least one planar antenna (910), referred to as a T-shaped antenna, comprising a first metal excitation surface and a first ground plane which are superimposed, at least one of the first ground plane and the first metal excitation surface having a T-shaped region; the radiation pattern of the T-shaped antenna presents two strong radiation side lobes which are oriented substantially parallel to the plane of the printed circuit and are separated by a weak central radiation area; and-at least one planar antenna (920), referred to as a rectangular antenna, comprising a second metallic excitation surface and a second ground plane which are superimposed, the second metallic excitation surface comprising a rectangular region, the rectangular region has a generally rectangular shape and is configured to cause the radiation pattern of the rectangular antenna to exhibit two strong radiation sidelobes oriented substantially orthogonal to the plane of the printed circuit and separated by a weak central radiation region.

Description

Technical Field

[0001] The present invention relates to the motor vehicle field and more particularly to a device for transmitting and / or receiving radio frequency signals, intended to form part of a motion detection system in a motor vehicle. Background Art

[0002] Motion detection systems are known in the prior art that are intended to be integrated into a motor vehicle for detecting a motion made by a user located outside or even inside the vehicle. The motion detection is then used to control the activation of a predetermined function of the motor vehicle, in particular the opening of an active cover, such as a side door or a tailgate or a trunk access door.

[0003] Motion detection is advantageously based on the emission of radio frequency signals and the analysis of return signals reflected by the environment, in particular by moving objects in the environment. The analysis may include: determining a phase shift associated with the instantaneous position of the object; and / or determining a Doppler frequency associated with the instantaneous velocity of the object.

[0004] In this context, the term "radio frequency" relates to an electromagnetic signal whose carrier frequency is between 3 kHz and 300 GHz, more preferably between 2 GHz and 30 GHz.

[0005] The transmission and reception of radio frequency signals can be performed by means of at least one planar antenna (antenne planaire) (or "antenne patch") integrated on a printed circuit, as described, for example, in patent application EP 3 546 979. A patch antenna comprises a metallic excitation surface, generally of square shape, separated from a ground plane by a dielectric substrate. Patch antennas have the advantage of providing a large aperture beam directed along an axis orthogonal to the plane of the printed circuit. Figure 1A A motor vehicle 1 is illustrated in a schematic manner, which is equipped with such a transmitting and / or receiving device 10 , which is arranged here at the rear of the vehicle 1 .

[0006] exist Figure 1B and Figure 1C , the rear area of ​​the vehicle 1 is shown schematically and in a top view. A transmitting and / or receiving device 10 is located in the central area of ​​the rear edge of the vehicle 1 . Figure 1B and Figure 1C Also shown is a user's foot 11 ready to perform a predetermined action intended to control the opening of the tailgate of the vehicle.

[0007] exist Figure 1B In FIG. 1 , the foot 11 is located at a distance d0 from the rear edge of the vehicle, facing the transmitting and / or receiving device 10. The foot 11 is then at a distance d1 from the transmitting and / or receiving device 10. Figure 1C, the foot 11 is still at a distance d0 from the rear edge of the vehicle, but it is laterally offset relative to the transmitting and / or receiving device 10. The foot 11 is then at a distance d2 from the transmitting and / or receiving device 10, wherein d2 is greater than d1.

[0008] The power transmitted by the RF antenna is 1 / d 2 where d is the distance to the target. The power of the signal returning to the transmitting and / or receiving device 10 is therefore reduced by 1 / d 2 The square change of .

[0009] One object of the present invention is to provide a solution which allows Figure 1B When positioned as in the example above, the antenna is not blinded, and when the foot is positioned as in the example above, the antenna is not blinded. Figure 1C In other words, one object of the invention is to propose a device for transmitting and / or receiving radio frequency signals, intended to be integrated into a motion detection system in a motor vehicle and allowing the influence on the positioning of a target (for example a foot of a user) to be limited depending on whether the target is aligned or offset in the lateral direction relative to the transmitting and / or receiving device. Summary of the invention

[0010] This object is achieved with a device for transmitting and / or receiving radio frequency signals, the device being intended to be integrated into a motion detection system in a motor vehicle and comprising:

[0011] - printed circuits;

[0012] - at least one first radiofrequency antenna integrated on the printed circuit and dedicated to transmitting and / or receiving radiofrequency signals propagating in the first detection zone; and

[0013] - at least one second radiofrequency antenna integrated on the printed circuit and dedicated to transmitting and / or receiving radiofrequency signals propagating in a second detection zone different from the first detection zone.

[0014] According to the present invention:

[0015] - at least one first radio frequency antenna is configured to: present a radiation pattern having two strong radiation side lobes separated by a weak central radiating region, the two lobes being oriented substantially parallel to the plane of the printed circuit; and

[0016] - at least one second radio frequency antenna is configured to present a radiation pattern having two strong radiation side lobes separated by a weak central radiating region, the two lobes being oriented substantially orthogonal to the plane of the printed circuit (the term "substantially" being defined hereinafter).

[0017] More particularly, according to the present invention:

[0018] at least one first radio frequency antenna is constituted by at least one planar antenna called a T-shaped antenna, the T-shaped antenna comprising a superimposed first metallic excitation surface and a first ground plane, at least one of the first ground plane and the first metallic excitation surface having a T-shaped area, so that the radiation pattern of the T-shaped antenna exhibits two strong radiation side lobes separated by a weak central radiation area; and

[0019] -At least one second RF antenna is constituted by at least one planar antenna referred to as a rectangular antenna, the rectangular antenna comprising a superimposed second metallic excitation surface and a second ground plane, the second metallic excitation surface comprising a rectangular area having a generally rectangular shape and configured to cause the radiation pattern of the rectangular antenna to present two strong radiation side lobes separated by a weak central radiation region.

[0020] By virtue of its T-shaped area, at least one T-shaped antenna presents a radiation pattern with two strong radiation side lobes separated by a weak central radiation area. Thus, the variation of the intensity of the radio frequency signal reflected by the target is strongly reduced depending on whether the target is aligned or offset in the lateral direction relative to the antenna.

[0021] By virtue of its rectangular area, at least one rectangular antenna presents a radiation pattern with two strong radiation side lobes separated by a weak central radiation area. Thus, the variation of the intensity of the radio frequency signal reflected by the target is strongly reduced depending on whether the target is aligned or offset in the lateral direction relative to the antenna.

[0022] The invention thus allows providing a device for transmitting and / or receiving radio frequency signals intended to be integrated into a motion detection system in a motor vehicle and which allows limiting the influence on the positioning of a target depending on whether the target is laterally aligned or offset relative to the transmitting and / or receiving device.

[0023] An obvious solution for solving this technical problem would have been to use pairs of antennas, each of which transmits in one of two opposite lateral directions.

[0024] The idea on which the invention is based is to adapt the radiation pattern of the planar antenna instead. This solution allows to retain a limited number of antennas and thus provide a compact device with reduced manufacturing costs.

[0025] This compactness is particularly advantageous in the automotive sector, where the presence of reinforcements, in particular at the rear of the vehicle, leaves only a small space available for elements such as the device according to the invention.

[0026] The present invention also provides a wide viewing angle by virtue of the use of a planar antenna.

[0027] The T-shaped antenna according to the invention also allows for radiation outside of directions orthogonal to the plane of the printed circuit without resorting to a square planar antenna mesh. This again ensures optimum compactness.

[0028] In a favorable way:

[0029] - the first detection zone is oriented along a plane substantially parallel to the plane of the printed circuit; and

[0030] - The second detection zone is oriented along a plane that is substantially orthogonal to the plane of the printed circuit.

[0031] Preferably:

[0032] - two strong radiation side lobes of the radiation pattern of the T-shaped antenna are directed along two respective axes, both lying in a plane substantially parallel to the plane of the printed circuit; and

[0033] The two strong radiation side lobes of the radiation pattern of the rectangular antenna are directed along two respective axes, both lying in planes substantially orthogonal to the plane of the printed circuit.

[0034] “Substantially parallel to the plane of the printed circuit” means “inclined by less than 20° by absolute value, even by less than 10° by absolute value, even by less than 5° by absolute value relative to the plane of the printed circuit”.

[0035] “Substantially orthogonal to the plane of the printed circuit” means “inclined by less than 20° in absolute value, even less than 10° in absolute value, even still less than 5° in absolute value relative to the plane orthogonal to the plane of the printed circuit”.

[0036] Preferably, the T-shaped region comprises a base portion and an upper portion, wherein the upper portion is formed by a first straight bar of length L1, and wherein the base portion is formed by a second straight bar perpendicular to the first straight bar.

[0037] Advantageously, the ratio L1 / λ 1 Between 1 / 8 and 1 / 6, where λ 1 It is the center wavelength of the RF signal transmitted and / or received by the T-Antenna in use.

[0038] The T-shaped region may have a height L2 defined along an axis parallel to the second straight rod, and a ratio L2 / λ 1 can be between 0.45 and 0.65, where λ 1 It is the center wavelength of the RF signal transmitted and / or received by the T-Antenna in use.

[0039] Advantageously, the T-shaped region belongs to one of the first ground plane and the first metallic energization surface, wherein the base of the T coincides with and is aligned with the straight region of the other of the first ground plane and the first metallic energization surface.

[0040] As a variant, the T-shaped area may belong to one of the first ground plane and the first metallic energizing surface and extend opposite a second T-shaped area belonging to the other of the first ground plane and the first metallic energizing surface.

[0041] Preferably, the rectangular area of ​​the rectangular antenna has a height L3 and a width L4, wherein the ratio L3 / L4 is greater than or equal to 1.5.

[0042] Ratio L3 / λ 2 is advantageously between 0.8 and 1, where λ 2 is the center wavelength of the RF signal transmitted and / or received by the rectangular antenna in use.

[0043] Ratio L4 / λ 2 can be between 0.45 and 0.55, where λ 2 is the center wavelength of the RF signal transmitted and / or received by the rectangular antenna in use.

[0044] In a favorable way:

[0045] - the T-shaped antenna is configured so that its two strong radiation side lobes are directed along two respective axes inclined to each other at an angle between 120° and 160°; and

[0046] The rectangular antenna is configured such that its two strong radiation side lobes are directed along two respective axes inclined to each other at an angle between 120° and 160°.

[0047] The invention also covers a motion detection system intended to be integrated into a motor vehicle and comprising:

[0048] - a device according to the invention; and

[0049] - a signal processing module configured to receive as input an electrical signal from the device and to analyse the electrical signal so as to provide as output information related to an action performed by a human operator.

[0050] Preferably, the system further comprises an opening control unit configured to receive as input information relating to an action performed by the human operator and in response provide instructions for opening the flap of the motor vehicle.

[0051] The invention also covers a motor vehicle comprising a device according to the invention, wherein in use the device is arranged at the rear of the motor vehicle, wherein one of the first detection zone and the second detection zone is oriented towards the rear of the vehicle, and wherein the other of the first detection zone and the second detection zone is oriented towards the ground. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Other features and advantages of the present invention will become more apparent upon reading the following description. The description is purely illustrative and should be read with reference to the accompanying drawings, in which:

[0053] [ Figure 1A ] illustrates in a schematic manner a motor vehicle equipped with a transmitting and / or receiving device according to the prior art;

[0054] [ Figure 1B ]Illustrated in a schematic manner Figure 1A a device and a foot positioned facing the device;

[0055] [ Figure 1C ]Illustrated in a schematic manner Figure 1A a device and a foot laterally offset relative to the device;

[0056] [ Figure 2 ] Figure 2 A motor vehicle equipped with a transmitting and / or receiving device according to the invention is illustrated in a schematic manner;

[0057] [ Figure 3A ]、[ Figure 3B ]、[ Figure 3C ]、[ Figure 3D ] illustrates in a schematic manner according to various views a first embodiment of a T-shaped antenna in a transmitting and / or receiving device according to the invention;

[0058] [ Figure 4A ]、[ Figure 4B ] to illustrate schematically the use of FIG. 3A to FIG. 3D T-shaped antenna;

[0059] [ Figure 5A ]、[ Figure 5B ]、[ Figure 5C ] illustrates in a schematic manner according to various views a second embodiment of a T-shaped antenna in a transmitting and / or receiving device according to the invention;

[0060] [ Fig. 6A ]、[ Figure 6B ]、[ Figure 6C ] illustrates in a schematic manner according to various views a third embodiment of a T-shaped antenna in a transmitting and / or receiving device according to the invention;

[0061] [ Fig. 7A ]、[ Figure 7B ]、[ Figure 7C ]、[ Fig.7D ] illustrates in a schematic manner in various views a first embodiment of a rectangular antenna in a transmitting and / or receiving device according to the invention;

[0062] [ Fig. 8A ]、[ Figure 8B ] to illustrate schematically the use of 7A to 7D Rectangular antenna;

[0063] [ Fig. 9 ] illustrates in a schematic manner an example of a transmitting and / or receiving device according to the present invention; and

[0064] [ Fig.10 ] illustrates in a schematic manner an action detection system according to the present invention. DETAILED DESCRIPTION

[0065] In at least some of the figures, the axes of an orthogonal coordinate system (Oxyz) have been indicated.

[0066] Figure 2 A motor vehicle 2 which is equipped with a transmitting and / or receiving device 20 according to the invention is illustrated in a schematic manner.

[0067] Here, but in a non-limiting manner, the transmitting and / or receiving device 20 is arranged at the rear of the vehicle 2 . The device 20 here forms part of a motion detection system intended to detect foot movements made by a human operator standing behind the vehicle 2 .

[0068] According to the invention, the transmitting and / or receiving device 20 comprises:

[0069] - printed circuits (see below);

[0070] - at least one first radio frequency antenna dedicated to transmitting and / or receiving radio frequency signals propagating in the first detection zone Z1; and

[0071] - at least one second radiofrequency antenna dedicated to transmitting and / or receiving radiofrequency signals propagating in the second detection zone Z2.

[0072] It is possible to have a single first radio frequency antenna (respectively, a second radio frequency antenna) that performs both transmission and reception of signals. As a variant, it is possible to have two first radio frequency antennas (respectively, two second radio frequency antennas) that perform transmission or reception of signals, respectively. This variant unexpectedly provides greater compactness.

[0073] Here, the first detection zone Z1 extends behind the vehicle 2, while the second detection zone Z2 extends under the vehicle 2. Preferably, the first detection zone Z1 and the second detection zone Z2 are adjacent. Together, they cover the entire zone in which a foot moving in a swinging motion at the rear of the vehicle 2 moves. The use of these two detection zones provides an optimal differentiation of interfering movements such as pedestrians passing behind the vehicle. Furthermore, the antenna associated with the first transmission zone Z1 can be used to detect the presence of a vehicle in the vicinity and control the wake-up of a motion detection system comprising the device 20 according to the invention.

[0074] According to the present invention:

[0075] - the first radio frequency antenna associated with the first detection zone Z1 is a planar antenna, referred to as a T-shaped antenna, described below; and

[0076] The second radiofrequency antenna associated with the second detection zone Z2 is a planar antenna, called a rectangular antenna, described below.

[0077] First refer to FIG. 3A to FIG. 3D A first embodiment of a T-shaped antenna in a device according to the invention is described.

[0078] The T-shaped antenna 310 is formed on a printed circuit and includes the following elements stacked in the following order along an (Oz) axis orthogonal to the (Oxy) plane of the printed circuit:

[0079] - a first metal excitation surface 311;

[0080] - a dielectric substrate 312; and

[0081] - A first ground plane 313 .

[0082] Figure 3A Antenna 310 is shown in a cross-sectional view in an (Oyz) plane orthogonal to the (Oxy) plane.

[0083] The first ground plane 313 designates a conductive flat metal surface that is intended to be electrically connected to the electrical ground of the electrical circuit housing the antenna 310 .

[0084] The first metal excitation surface 311 indicates a conductive flat metal surface, which is intended to be electrically connected to an electrical supply source providing an electrical excitation signal. The electrical supply source is, for example, an oscillator. The electrical excitation signal has a carrier wave whose frequency belongs to the radio frequency domain.

[0085] Preferably, the size of the first ground plane 313 is larger than that of the first metal excitation surface 311 , wherein the ratio between their respective areas is greater than or equal to 5, or even greater than or equal to 10.

[0086] The dielectric substrate 312 corresponds to a layer of a single-layer or multi-layer printed circuit. The first metallic activation surface 311 and the first ground plane 313 correspond to metallization on respective faces of said layer.

[0087] Figure 3B The first ground plane 313 is shown in a top view in the (Oxy) plane. The first ground plane 313 is composed of a T-shaped region 313A and a main region 313B that are formed integrally together.

[0088] The main region 313B is, for example but not in a limiting manner, rectangular in shape. Its area is greater than the area of ​​the region 313A, wherein for example the ratio between the respective areas of the region 313A and the region 313B is greater than 10.

[0089] The “T-shape” means “composed of a first segment 3131A forming an upper portion and a second segment 3132A forming a base portion, wherein one end of the second segment 3132A is cut into a central region of the first segment 3131A”.

[0090] Preferably, and as in Figure 3B As shown in FIG. 1 , the first segment 3131A and / or the second segment 3132A are straight. Preferably, and as shown in FIG. Figure 3B As shown in FIG. 3 , the second segment 3132A intercepts the first segment 3131A at the center of the first segment. Also preferably, and as shown in FIG. Figure 3B As shown in FIG. 3 , the first segment 3131A and the second segment 3132A are perpendicular to each other.

[0091] The first section 3131A has a length L1. Advantageously, the ratio L1 / λ 1 Between 1 / 8 and 1 / 6, where λ 1 is the central wavelength of the radio frequency signal that the antenna 310 is configured to transmit and / or receive. Thus, for a signal whose carrier is between 2 GHz and 30 GHz, the length L1 is, for example, between 1 mm and 25 mm.

[0092] The T-shaped region 313A has a height L2. The height L2 is defined in the (Oxy) plane along an axis perpendicular to the first section 3131A. Here, the height L2 corresponds to the extension of the second section 3132A plus the thickness of the first section 3131A.

[0093] Advantageously, the ratio L2 / λ 1 is close to 0.5, for example between 0.4 and 0.6, more preferably between 0.45 and 0.55, more preferably still between 0.48 and 0.52, wherein λ 1As defined above. Thus, for a signal whose carrier is between 2 GHz and 30 GHz, the length L2 is for example between 4 mm and 90 mm.

[0094] Advantageously, the ratio L2 / L1 is between 2.5 and 5, more preferably between 3 and 4.

[0095] Figure 3C The first metal energization surface 311 is shown as a top view in the (Oxy) plane. The first metal energization surface 311 is here formed by a reduced width conductive line 311A ​​and an impedance matching surface 311B.

[0096] One end of the conductive wire 311A ​​has a straight segment shape, and the remaining portion of the conductive wire 311A ​​ensures electrical connection with an electrical supply source.

[0097] The impedance matching surface 311B is rectangular in shape, wider than the conductive line 311A ​​and centered thereon in the width direction. The impedance matching surface 311B is intended to perform simple impedance matching to match the impedance of the antenna 310 to the 50 ohm electrical trace feeding it.

[0098] Figure 3D The antenna 310 is shown from a top view in the (Oxy) plane, with the dielectric substrate being transparent to facilitate reading of the figure. It is seen that the antenna 310 has a planar symmetry with respect to a plane orthogonal to the (Oxy) plane.

[0099] Figure 3D It is also shown that at least a portion of the straight segment 311A ​​of the first metal excitation surface 311 overlaps with the base 3132A of the T-shaped area 313A of the first ground plane 313. In particular, the base 3132A is completely covered again by the straight segment 311A. One end of the straight segment 311A ​​extends until it faces the upper edge of the T-shaped area 313A, at the upper part 3131A of the T-shaped area. Here, and in an advantageous manner, the straight segment 311A ​​and the base 3132A of the T-shaped area have the same width.

[0100] As for the impedance matching surface 311B, it is located in a main area 313B facing the first ground plane 313, offset with respect to the T-shaped area 313A.

[0101] Figure 4A and Figure 4B Schematically illustrates the use of FIG. 3A to FIG. 3D T-shaped antenna 310. Figure 4A is a top view in the (Oxy) plane, where the dielectric substrate 312 is shown transparently. Figure 4B is a cross-sectional view in the (Oyz) plane.

[0102] In use, the first ground plane 313 is electrically connected to the electrical ground 31, while the first metallic energizing surface 311 is electrically connected to the electrical supply 32, as described above.

[0103] The T-shaped antenna 310 exhibits a radiation pattern that includes two strong radiation side lobes 341 separated by a weak central radiation region 342. To facilitate understanding, the radiation pattern is shown here as superimposed on the antenna. The figure does not show the exact location of the emission origin point at the antenna (especially because the far-field emission is of interest). The relevant teaching is the general shape and orientation of the radiation pattern in space.

[0104] Each of the side lobes 341 is centered on a respective axis 343. The axis 343 lies in a plane substantially parallel to the plane of the printed circuit. "Substantially parallel" means that the angle of inclination relative to the plane of the printed circuit is less than or equal to 20°, even less than or equal to 10°, even less than or equal to 5° in absolute value. The volume covered by the radiation pattern of the T-shaped antenna 310 advantageously corresponds to the first detection zone Z1, respectively to the second detection zone Z2 (see Figure 2 ).

[0105] Axis 343 (and side lobe 341 ) here have a plane symmetry with respect to a plane orthogonal to the (Oxy) plane of the printed circuit and parallel to base 3132A of the T-shaped region. Axis 343 (and side lobe 341 ) here have a plane symmetry with respect to the (Oxz) plane.

[0106] The angular difference between the axes 343 is advantageously between 120° and 160°, wherein an angle of 180° corresponds to π radians.

[0107] Next refer to FIG. 5A to FIG. 5C The illustrated variant 510 will only be described with respect to the variant 510. FIG. 3A to FIG. 3C The difference in the antenna is used to describe variation 510.

[0108] Figure 5A The first ground plane 513 is shown in a top view in the (Oxy) plane. The first ground plane 513 is formed here by a straight region 513A and a main region 513B which are formed together as one piece.

[0109] Figure 5B The first metal energizing surface 511 is shown as a top view in the (Oxy) plane. The first metal energizing surface 511 is formed here by a conductive line 511A, a T-shaped region 511B and an impedance matching surface 511C.

[0110] The definition of the T-shaped area is the same as above.

[0111] The impedance matching surface 511C is as described above. It is located at a distance from the T-shaped region.

[0112] The conductive line 511A is located in a continuation of the base of the T in the T-shaped region 511B, and has the same width as the base.

[0113] Figure 5C Antenna 510 is shown from a top view in the (Oxy) plane, with the dielectric substrate being transparent to facilitate reading of the figure.

[0114] Figure 5C It is shown that the straight segment 513A of the first ground plane 513 coincides with the base of the T of the T-shaped region 511B.

[0115] The straight section 513A extends to the upper end of the T-shaped region 511B on the upper side of the T. The straight section 513A does not extend beyond the upper portion of the T.

[0116] Opposite ends of the straight segment 513A are located at a junction with the main region 513B of the first ground plane 513 , defining a junction between the conductive line 511A and the T-shaped region 511B.

[0117] The details given above regarding the dimensions of the T-shaped area apply in the same way in this variant.

[0118] In use, the first ground plane and the first metallic excitation surface are connected to the reference Figure 4A and Figure 4B Connect in the same way as described to obtain a similar radiation pattern.

[0119] Next refer to FIG. 6A to FIG. 6C The illustrated variant 610 will only be described with respect to the variant 610. FIG. 5A to FIG. 5C The difference in the antenna is used to describe variation 610.

[0120] Here, the first ground plane 613 is as shown in FIG. FIG. 3A to FIG. 3C It is thus composed of a T-shaped region 613A and a main region 613B ( Fig. 6A ).

[0121] In addition, the first metal excitation surface 611 is as shown in FIG. FIG. 5A to FIG. 5C It is thus composed of a conductive line 611A, a T-shaped region 611B and an impedance matching surface 611C ( Figure 6B ).

[0122] The T-shaped region 611B belonging to the first metal excitation surface 611 overlaps the T-shaped region 613A belonging to the first ground plane ( Figure 6C ). The impedance matching is therefore optimal.

[0123] In use, the first ground plane and the first metallic excitation surface are connected to the reference Figure 4A and Figure 4B Connect in the same way as described to obtain a similar radiation pattern.

[0124] Next refer to Figures 7A to 7D An embodiment of a rectangular antenna in a transmitting and / or receiving device according to the present invention is described.

[0125] In the same manner as the T-shaped antenna, the rectangular antenna 720T is formed on a printed circuit and includes:

[0126] - A second metal excitation surface 721;

[0127] - a dielectric substrate 722; and

[0128] - A second ground plane 723 .

[0129] Fig. 7A The rectangular antenna 720 is shown in a cross-sectional view in the (Oxz) plane orthogonal to the (Oxy) plane of the printed circuit.

[0130] The definitions of the ground plane and correspondingly the metallic excitation surface are the same as given with reference to the T-shaped antenna. Likewise, the second ground plane 723 and the second metallic excitation surface 721 are formed by metallization on two opposite faces of a layer of a printed circuit (dielectric substrate 722).

[0131] Here, and as in Figure 7B As shown in FIG. 7 , the second ground plane 723 is formed by a flat metal surface, for example, a square or rectangular surface.

[0132] Figure 7C The second metal excitation surface 721 is shown in a top view in the (Oxy) plane. The second metal excitation surface 721 includes a rectangular area 721A, an impedance matching area 721B, and a conductive line 721C, which ensures electrical connection with an electrical supply source. The second metal excitation surface 721 has a plane symmetry with respect to a plane orthogonal to the (Oxy) plane.

[0133] Rectangular region 721A is here at the origin of electromagnetic radiation of rectangular antenna 720. Rectangular region 721A has a generally rectangular shape.

[0134] Here, the rectangular area 721A has a rectangular shape, and has two small recesses 7211A on both sides thereof in the junction area with the conductive line 721C. The two small recesses 7211A participate in 50Ω impedance matching over a wide frequency range. The cumulative surface of these recesses is less than 10% of the total surface of the rectangular area 721A. The rectangle has a height L3 defined here along the (Oy) axis and a width L4 defined here along the (Ox) axis, wherein L3 is strictly greater than L4.

[0135] Advantageously, the ratio L3 / L4 is greater than or equal to 1.5, even greater than or equal to 1.8. The ratio is advantageously between 1.5 and 2.3, even between 1.8 and 2.3, including the limits. In this respect, the invention differs from the substantially square-shaped patch antennas known in the prior art.

[0136] Advantageously, the ratio L3 / λ 2 Between 0.8 and 1, where λ 2 is the center wavelength (preferably, λ) of the RF signal that the rectangular antenna 720 is configured to transmit and / or receive. 1 =λ 2 ). Thus, for a signal whose carrier is between 2 GHz and 30 GHz, the length L3 is, for example, between 8 mm and 150 mm. In this respect, the present invention differs from the prior art known in which the shape is substantially equal to the side length λ 2 / 2 square shaped patch antenna.

[0137] Also in an advantageous manner, the ratio L4 / λ 2 is close to 0.5, for example between 0.4 and 0.6, more preferably between 0.45 and 0.55, and still more preferably between 0.48 and 0.52, wherein λ 2 As described above, therefore, for a signal whose carrier is between 2 GHz and 30 GHz, the length L4 is, for example, between 4 mm and 90 mm.

[0138] Advantageously, L2 and L4 are substantially equal, differing by approximately + / - 10%.

[0139] Rectangular region 721A is located at one end of conductive line 721C, in direct physical contact with the latter.

[0140] Conductive line 721C has a reduced width, smaller than dimensions L3 and L4 of rectangular area 721 A. Here, but in a non-limiting manner, conductive line 721C extends along a linear axis.

[0141] The impedance matching region 721B is rectangular in shape, with a surface smaller than that of the rectangular region 721A, and has a surface ratio greater than or equal to 4. The impedance matching region 721B is located at a distance from the rectangular region 721A along the conductive line. The impedance matching region 721B is centered with the conductive line 721C in the width direction. It is intended only to perform impedance matching.

[0142] Fig.7D The rectangular antenna 720 is shown from a top view in the (Oxy) plane, with the dielectric substrate being transparent to facilitate reading of the figure. Fig.7D The rectangular region 721A (and the impedance matching region 721B) are shown extending opposite the second ground plane 723 .

[0143] Fig. 8A and Figure 8B Schematically illustrates the use of 7A to 7D Rectangular antenna 720. Fig. 8A is a cross-sectional view in the (Oyz) plane orthogonal to the plane of the printed circuit. Figure 8B is a top view in the (Oxy) plane, where the dielectric substrate is represented as transparent.

[0144] In use, the second ground plane 723 is electrically connected to the electrical ground 71, while the second metallic energizing surface 721 is electrically connected to the electrical supply 72, as described above.

[0145] Rectangular antenna 720 exhibits a radiation pattern comprising two strong radiation side lobes 741 separated by a weak central radiating region 742. Again, the figure does not represent the exact location of the emission origin point at the antenna. The relevant teaching is the general shape and orientation of the radiation pattern in space.

[0146] Each of the side lobes 741 is centered on a respective axis 743. The axis 743 lies in a plane substantially orthogonal to the plane of the printed circuit. "Substantially orthogonal" means that the angle of inclination relative to the plane orthogonal to the plane of the printed circuit is less than or equal to 20°, even less than or equal to 10°, even less than or equal to 5° in absolute value. The volume covered by the radiation pattern of the rectangular antenna 720 advantageously corresponds to the second detection zone Z2, respectively to the first detection zone Z1 (see Figure 2 ).

[0147] The axis 743 (and the side lobe 741) has a plane symmetry here with respect to a plane orthogonal to the (Oxy) plane of the printed circuit and parallel to the long side of the rectangular area 721A. The axis 743 (and the side lobe 741) has a plane symmetry here with respect to the (Oxz) plane parallel to the long side L3 of the rectangular area 721A. The angular difference between the axes 743 is advantageously between 120° and 160°.

[0148] Fig. 9 An example of a transmitting and / or receiving device 900 according to the invention is illustrated in a schematic manner. The device 900 comprises, integrated on a same printed circuit 930:

[0149] - T-shaped antenna 910 according to the present invention, as in FIG. 3A to FIG. 3D as shown in the figure; and

[0150] -Rectangular antenna 920 according to the present invention, as in 7A to 7D As shown in the figure.

[0151] In use the same metal surface may respectively form the first and second ground planes for both antennas and be connected to electrical ground 91. As a variant, in use the first and second ground planes extend in different layers of the printed circuit and both are connected to electrical ground 91.

[0152] On opposite sides of the printed circuit, different metal surfaces form the metal excitation surface of the T-shaped antenna and the metal excitation surface of the rectangular antenna, respectively, which in use are connected to a first electrical supply 92 and a second electrical supply 92', respectively.

[0153] in a favorable manner, and as in Fig. 9 As shown in , the base of the T of antenna 910 is perpendicular to the long side of the rectangular area of ​​rectangular antenna 920. This arrangement allows for the desired orientation of the four main transmit lobes associated with the two antennas together in the context of motion detection as described in the background.

[0154] in a favorable manner, and as in Fig. 9 As shown in FIG. 1 , the T-shaped antenna 910 and the rectangular antenna 920 are also aligned along an axis parallel to the base and the long sides of the T. This arrangement allows to minimize interference between the two antennas. It also ensures a substantially common origin between the respective radiations of the two antennas.

[0155] In an advantageous manner, the device according to the invention also comprises an electronic component (not represented) for shaping and / or preprocessing of electrical signals, which is integrated on the same printed circuit. Such an electronic component is configured to shape the respective signal sent as input by each of the antennas of the transmitting and / or receiving device according to the invention, and / or is configured to perform preprocessing (in particular mixing and filtering) of the electrical signal provided as output by each of said antennas.

[0156] Preferably, the printed circuit accommodates at least one antenna whose radiation pattern is oriented along a plane substantially parallel to the plane of the printed circuit and at least one antenna whose radiation pattern is similar but oriented along a plane substantially orthogonal to the printed circuit. Thus, a 90° rotation of the printed circuit preserves the orientation of the radiation pattern. The printed circuit can thus be freely oriented according to local integration constraints.

[0157] at last, Fig.10 A motion detection system 1000 according to the invention is illustrated in a schematic manner. The latter comprises:

[0158] - a transmitting and / or receiving device 100 according to the invention; and

[0159] A signal processing module 150 configured to receive as input the electrical signals from the device 100, to analyse said electrical signals and to provide as output information 151 related to the actions performed by the human operator.

[0160] The signal processing module 150 includes at least one processor, at least one memory and input and output interfaces, which may be, for example, at least one microcontroller.

[0161] Here, and in an advantageous manner, the system 1000 further comprises an opening control unit 160 configured to receive as input information 151 relating to an action and to provide instructions 161 for opening a flap of the motor vehicle when said information 151 relates to a predetermined action.

[0162] The opening control unit 160 comprises at least one processor, at least one memory and an input and output interface, which is, for example, at least one microcontroller.

[0163] The invention is not limited to the examples described above and covers many variants of the device according to the invention corresponding, for example, to other combinations of T-shaped antennas and rectangular antennas.

[0164] The invention has been described in the context of opening a control cabin or tailgate, but finds application in other remote control of motor vehicle functions, such as opening of a side door using the device according to the invention integrated in a side pillar of the vehicle.

[0165] In an undeclared variant of the T-shaped antenna, the T-shaped area is formed by a half T located in the first ground plane and a half T belonging to the first metallic excitation surface, wherein the two half Ts are symmetrical to each other according to a plane orthogonal to the plane of the printed circuit.

Claims

1. A device (20, 900) for transmitting and / or receiving radio frequency signals, which is intended to be integrated into a motion detection system in a motor vehicle and comprises: - a printed circuit (930); - at least one first radiofrequency antenna (310, 510, 610, 910) integrated on the printed circuit and dedicated to transmitting and / or receiving radiofrequency signals propagating in the first detection zone (Z1); and - at least one second radiofrequency antenna (720, 920) integrated on the printed circuit and dedicated to transmitting and / or receiving radiofrequency signals propagating in a second detection zone (Z2) different from the first detection zone; Features: - the at least one first radio frequency antenna (310, 510, 610, 910) is constituted by at least one planar antenna called a T-shaped antenna, the T-shaped antenna comprising a superimposed first metal excitation surface (311, 511, 611) and a first ground plane (313, 513, 613), at least one of the first ground plane and the first metal excitation surface having a T-shaped area (313A, 511B, 613A), so that the radiation pattern of the T-shaped antenna exhibits two strong radiation side lobes (341) separated by a weak central radiation area (342); and -The at least one second RF antenna (720, 920) is composed of at least one planar antenna called a rectangular antenna, which includes a superimposed second metal excitation surface (721) and a second ground plane (723), the second metal excitation surface including a rectangular area (721A), the rectangular area having a generally rectangular shape and configured to cause the radiation pattern of the rectangular antenna to present two strong radiation side lobes (741) separated by a weak central radiation area (742).

2. The device (20, 900) according to claim 1, characterized in that: - said two strong radiation side lobes (341) of the radiation pattern of the T-shaped antenna are oriented along two respective axes (343) both lying in planes inclined at less than 10° in absolute value relative to the plane of the printed circuit (930); and - the two strong radiation side lobes (741) of the radiation pattern of the rectangular antenna are oriented along two respective axes (743) both located in planes inclined less than 10° in absolute value relative to a plane orthogonal to the plane of the printed circuit (930).

3. The device (20, 900) according to claim 1 or 2, characterized in that The T-shaped region (313A, 511B, 613A) comprises a base (3132A) and an upper portion (3131A), wherein the upper portion is formed by a first straight bar of length L1, and wherein the base is formed by a second straight bar perpendicular to the first straight bar.

4. The device (20, 900) according to claim 3, characterized in that The ratio L1 / λ1 is between 1 / 8 and 1 / 6, where λ1 is the center wavelength of a radio frequency signal transmitted and / or received by the T-shaped antenna (310, 510, 610, 910) in use.

5. The device (20, 900) according to claim 3 or 4, characterized in that The T-shaped region (313A, 511B, 613A) has a height L2 defined along an axis parallel to the second straight rod (3132A), and a ratio L2 / λ1 is between 0.45 and 0.65, where λ1 is the center wavelength of a radio frequency signal transmitted and / or received by the T-shaped antenna (310, 510, 610, 910) in use.

6. The device (20, 900) according to any one of claims 3 to 5, characterized in that A T-shaped region (313A, 511B) belongs to the first ground plane (313, 513) and the first metal excitation surface (311, 511), wherein the base (3132A) of the T overlaps and aligns with a straight region (311A, 513A) of the other of the first ground plane and the first metal excitation surface.

7. The device (20) according to any one of claims 3 to 5, characterized in that The T-shaped region (613A) belongs to one of the first ground plane and the first metal excitation surface, and extends toward the second T-shaped region (611B) belonging to the other of the first ground plane and the first metal excitation surface.

8. The device (20, 900) according to any one of claims 1 to 7, characterized in that The T-shaped area (313A, 613A) belongs to the first ground plane (313, 613).

9. The device (20, 900) according to any one of claims 1 to 8, characterized in that The rectangular region (721A) of the rectangular antenna (720, 920) has a height L3 and a width L4, wherein the ratio L3 / L4 is greater than or equal to 1.

5.

10. The device (20, 900) according to claim 9, characterized in that The ratio L3 / λ2 is between 0.8 and 1, where λ2 is the center wavelength of a radio frequency signal transmitted and / or received by the rectangular antenna (720, 920) in use.

11. The device (20, 900) according to claim 9 or 10, characterized in that The ratio L4 / λ2 is between 0.45 and 0.55, where λ2 is the center wavelength of a radio frequency signal transmitted and / or received by the rectangular antenna (720, 920) in use.

12. The device (20, 900) according to any one of claims 1 to 11, characterized in that: - the T-shaped antenna (310, 510, 610, 910) is configured so that its two strong radiation side lobes (341) are oriented along two respective axes (343) tilted to each other at an angle between 120° and 160°; and The rectangular antenna (720, 920) is configured so that its two strong radiation side lobes (741) are oriented along two respective axes (743) that are tilted to each other at an angle between 120° and 160°.

13. A motion detection system (1000) intended to be integrated into a motor vehicle (2) and comprising: - an apparatus (20, 900) as claimed in any one of claims 1 to 12; and - a signal processing module (150) configured to receive as input an electrical signal from the device (20, 900) and to analyse the electrical signal so as to provide as output information (151) related to an action performed by a human operator.

14. The system (1000) of claim 13, wherein: Also included is an opening control unit (160) configured to receive as input information (151) related to an action performed by a human operator and in response provide instructions (161) for opening a movable cover of the motor vehicle.

15. A motor vehicle (2) comprising a device (20, 900) as described in any one of claims 1 to 12, wherein in use, the device (20, 900) is arranged at the rear of the motor vehicle, wherein one of the first detection zone (Z1) and the second detection zone (Z2) is oriented towards the rear of the vehicle, and wherein the other of the first detection zone (Z1) and the second detection zone (Z2) is oriented towards the ground.

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