Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q5/00—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
  • H01Q5/30—Arrangements for providing operation on different wavebands
  • H01Q5/378—Combination of fed elements with parasitic elements
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q1/00—Details of, or arrangements associated with, antennas
  • H01Q1/36—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith
  • H01Q1/38—Structural form of radiating elements, e.g. cone, spiral, umbrella; Particular materials used therewith formed by a conductive layer on an insulating support
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
  • H01Q19/22—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of a single substantially straight conductive element
  • H01Q19/26—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of a single substantially straight conductive element the primary active element being end-fed and elongated
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q19/00—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic
  • H01Q19/28—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of two or more substantially straight conductive elements
  • H01Q19/32—Combinations of primary active antenna elements and units with secondary devices, e.g. with quasi-optical devices, for giving the antenna a desired directional characteristic using a secondary device in the form of two or more substantially straight conductive elements the primary active element being end-fed and elongated
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01Q—ANTENNAS, i.e. RADIO AERIALS
  • H01Q9/00—Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
  • H01Q9/04—Resonant antennas
  • H01Q9/30—Resonant antennas with feed to end of elongated active element, e.g. unipole

Definitions

• the present invention belongs to the field of compact directional antennas.
• the invention relates to a compact directional antenna suitable for geolocating connected objects emitting radio signals, as well as a device using such an antenna.
• the size of an antenna generally depends on the wavelength for which the antenna is designed: the lower the working frequency, the greater the associated wavelength, and the more the dimensions of an antenna suitable for this frequency of work are large.
• RF Harrington demonstrated in 1959 that an antenna whose dimensions can be included in a sphere of radius R has a directivity proportional to (R 2 + 2R). In other words, the more compact the antenna, the weaker its directivity.
• An existing solution for producing a directional antenna consists in placing several unit antenna elements in a network. Only one of these elements, called the “radiator element”, is supplied electrically. The other elements, called “parasitic elements” are supplied by mutual induction. The electromagnetic field radiated by the antenna in a given direction corresponds to the sum of the fields radiated by each of the elements. By correctly placing the various elements relative to each other, it is possible to focus the power radiated by the antenna in a preferred direction and therefore increase the directivity of the antenna.
• the various elements of the network are of the same nature and have similar shapes and dimensions. These are, for example, electric dipoles which can be formed by rods or metal ribbons.
• the best-known example of such an antenna is the Yagi-Uda antenna (named after its inventors, Hidetsugu Yagi and Shintaro Uda).
• the dimensions of a transmission or reception device using such an antenna depend not only on the dimensions of the antenna, but also on the dimensions of the electronic card which carries the various electronic components of the device.
• This electronic card is generally connectorized to the antenna, and it must be positioned so that it does not disturb the performance of the antenna. This generally contributes to relatively large dimensions of the transmission or reception device.
• the object of the present invention is to remedy all or part of the drawbacks of the prior art, in particular those described above, by proposing an antenna exhibiting good performance both in terms of directivity, of radiation efficiency and of compactness.
• the antenna according to the invention also has the possibility of integrating the electronic components of a reception device either directly on a ground plane of the antenna, or on a printed circuit board positioned opposite and close to the ground plane of the antenna. This makes it possible to limit the dimensions of the receiving device, while avoiding disturbing the performance of the antenna.
• the directivity of an antenna in one direction is the ratio between the pfd density radiated by the antenna in this direction at a given distance and the power density that would be radiated by an isotropic antenna radiating the same total power. .
• Directivity has no unit, it is usually expressed in isotropic decibels (dBi).
• dBi decibels
• the term “directivity of an antenna” is generally understood to mean the value of the directivity of the antenna in the direction in which the directivity is maximum.
• the radiation efficiency of an antenna is defined by the ratio between the radiated power and the power injected at the input of the antenna. This parameter reflects the losses present on the antenna.
• the gain of an antenna in a given direction is the product of the directivity of the antenna in that direction and the radiation efficiency of the antenna.
• the present invention proposes a directional antenna comprising an array of unit antenna elements.
• the array comprises an active antenna element, called a “radiator element”, intended to be electrically connected to a radiofrequency source or receiver, and at least one passive antenna element supplied by mutual induction, called a “parasitic element”.
• the radiator element is a parasitic resonator antenna comprising a monopoly, a ground plane and a parasitic cell placed in the near field of the monopoly.
• Such an antenna differs from antennas of the prior art in that the radiator element has a different nature from parasitic elements.
• the radiator element in fact exhibits a magnetic dipole behavior while the other elements of the network behave like electric dipoles.
• the antenna according to the invention is particularly efficient in terms of directivity and radiation efficiency while remaining very compact.
• the presence of a ground plane which is not generally sought in this type of antenna, can advantageously make it possible to integrate all or part of the electronic modules of a transmitter and / or receiver device comprising such a antenna.
• the invention may also include one or more of the following characteristics, taken in isolation or in any technically possible combination.
• the radiator element and said at least one parasitic element of the network are formed in the same plane. The use of a planar network makes it possible to limit the size of the antenna.
• the network comprises at least one parasitic element of reflector type and at least one parasitic element of director type.
• a reflector element and a director element are aligned with the radiator element, on either side of the radiator element, along an axis of the array corresponding to a direction in which the gain of the antenna is maximum.
• the presence of at least one reflector element and at least one director element improves the performance of the antenna in terms of directivity.
• the antenna has three parasitic elements including a reflector element and two directing elements, each parasitic element being formed by an electric dipole bent in the form of meanders.
• each parasitic element being formed by an electric dipole bent in the form of meanders.
• the monopoly is intended to be electrically connected to the radiofrequency source or receiver, and the parasitic cell of the radiator element takes the form of an open loop.
• the working frequency of the antenna is less than one gigahertz
• the array of elements has a length of less than twenty centimeters and a width of less than ten centimeters
• the antenna has a maximum value of Directivity greater than 8 dBi and radiation efficiency greater than -3 dB.
• the ground plane of the radiator element comprises electrical tracks for an electronic circuit of a transmission or reception device, said electrical tracks being etched within the ground plane.
• the present invention relates to a transmitter or receiver device comprising a directional antenna according to one any of the previous embodiments.
• the transmitter or receiver device further comprises an electronic circuit positioned opposite the ground plane of the radiator element of the antenna.
• Such an electronic circuit corresponds to a set of electronic components of at least one electronic module of the receiving device.
• the various electronic components are generally interconnected using a printed circuit on a printed circuit board (PCB, for “Printed Circuit Board” in English.
• PCB printed circuit board
• FIG. 1 a schematic representation of a first face of a printed circuit board on which is produced a particular embodiment of an antenna according to the invention
• FIG. 2 a schematic representation of the other side of the printed circuit board shown in Figure 1,
• FIG. 3 a particular embodiment of the parasitic cell of the radiator element of the antenna according to the invention
• FIG. 5 another particular embodiment of the parasitic cell
• FIG. 7 a radiation pattern of the antenna according to the invention for a particular embodiment
• FIG. 8 a radiation pattern of the antenna according to the invention for another particular embodiment
• FIG. 9 a detailed representation of the ground plane of the radiator element of the antenna according to a particular embodiment.
• FIG. 1 schematically shows a particular embodiment of an antenna 10 according to the invention.
• the antenna 10 comprises an array 12 of four unit antenna elements.
• Network 12 is a planar network. In other words, all the antenna elements forming the network 12 are arranged in the same plane. This makes it possible to limit the volume occupied by the antenna 10, and therefore to limit the dimensions of the receiving device which carries the antenna 10.
• the various antenna elements are arranged on a printed circuit board 1 1 (PCB for “Printed Circuit Board” in Anglo-Saxon literature).
• radiator element 20 When the antenna 10 operates in transmission, one of the elements, called “radiator element 20" is electrically supplied by an RF source, that is to say by an electric current oscillating at the frequency of a radio wave.
• radio wave is meant an electromagnetic wave whose frequency varies from a few Hertz (Hz) to several hundred Gigahertz (GHz). This current is for example conveyed between the source and the antenna by a power cable (for example a coaxial cable).
• the RF source and the power cable are not shown in the figures.
• the radiator element 20 When the antenna 10 is operating in reception, the radiator element 20 is electrically connected to an RF receiver. The electric current induced by the electromagnetic field observed at the radiator element 20 can thus be converted into an electrical signal and then amplified at the RF receiver.
• the connection between the antenna 10 and the RF receiver can be made, in a conventional manner, by a coaxial cable.
• the other three elements are not supplied electrically. These are passive elements supplied by coupling by mutual induction.
• This type of network 12 in which a single element is electrically supplied makes it possible to limit the size of the antenna 10 because there is no need to create a complex electric supply network for the different elements.
• the radiator element 20 and the three parasitic elements 30 are aligned in a direction 13 in which the gain of the antenna 10 is maximum.
• One of the parasitic elements 30 acts as a "reflector element 31", while the other two parasitic elements 30 act as "guiding elements 32".
• a reflector element 31 is disposed with respect to the radiator element 20 opposite to the direction 13 of maximum gain of the antenna 10.
• a directing element 32 is disposed with respect to the radiator element 20 in the direction 13 of. maximum gain of the antenna 10. In other words, a reflector element 31 and a directing element 32 are arranged on either side of the radiator element 20.
• the electric current which circulates in the radiator element 20 produces by radiation an electromagnetic field which induces currents in the other elements.
• the current induced in the parasitic elements 30 in turn produces other electromagnetic fields which induce current in the other elements (both in the parasitic elements 30 and in the radiator element 20).
• the current flowing in each element is the result of the interaction between all the elements. It depends on the positions and dimensions of each element.
• the electromagnetic field radiated by the antenna 10 in a given direction is the sum of the electromagnetic fields radiated by each of the elements of the network 12.
• Each element has a different amplitude and a different phase of the current. One can thus observe constructive or destructive additions of electromagnetic fields according to the phase shift specific to each element.
• a directing element 32 which is placed towards the front of the antenna 10 reinforces the electromagnetic field in the direction 13 (i.e. in the direction radiator element 20 towards the directing element 32).
• a reflector element 31 which is placed towards the rear of the antenna 10 reflects the electromagnetic field to strengthen it in the direction 13 (i.e. in the direction of the reflector element 31 towards the radiator element 20).
• the positions and dimensions of the elements of the network 12 are calculated so that the phases of the resulting currents are such that the addition of electromagnetic fields is minimal towards the back and maximum forward.
• the phase and the amplitude of the currents induced in the elements is such that the current induced in the radiator element 20 connected to the RF receiver is minimum for the waves coming from the rear and maximum for waves coming from the front relative to the direction 13.
• the parasitic elements 30 are electric dipoles formed by metal ribbons printed on the printed circuit board 11. As shown in Figure 1, to limit the dimensions of the antenna, each electrical dipole is bent in a meandering shape. Each dipole has two branches 33. The two branches 33 of a dipole are symmetrical with each other with respect to an axis along the direction 13 of maximum gain of the antenna 10 and passing through the middle of the card 1. 1 of the printed circuit on which the antenna 10 is manufactured. For each electric dipole, the two branches 33 can be separated by a phase shift circuit 34 comprising resistive, capacitive and / or inductive components making it possible to optimize the directivity performance of antenna 10. The phase shift circuits 34 make it possible in particular to introduce at the level of each parasitic element 30 the phase shift necessary to optimize the directivity of the antenna 10.
• Figure 1 shows one side of the printed circuit board 1 1 on which are arranged the various elements of the antenna 10.
• Figure 2 shows the other side of the printed circuit board 1 1.
• the radiator element 20 is a parasitic resonator antenna comprising a monopoly 21, a ground plane 22 and a parasitic cell 23 placed in the near field of the monopoly 21.
• the ground plane 22 comprises two superposed layers, each layer being respectively arranged on one face of the printed circuit board 1 1.
• the two layers of the ground plane 22 are thus facing each other.
• the two layers of the ground plane 22 are for example electrically connected to one another by a multitude of vias 24.
• the term “via” is understood to mean a metallized hole in the printed circuit board 11 which makes it possible to establish a connection. between the two faces of said card 11. It should be noted that nothing prevents the use of a ground plane 22 which has only a single layer disposed on only one of the faces of the printed circuit board 11.
• the ground plane 22 is made of an electrically conductive material, for example metal.
• the ground plane 22 has a rectangular shape.
• the ground plane 22 can be a flat electrical conductor taking another form, and the choice of a particular shape for the ground plane 22 only represents variants of the invention.
• the monopoly 21 is formed by a metal strip printed on the face of the printed circuit board 1 1 opposite the face on which the electric dipoles of the parasitic elements 30 are printed.
• the RF source (for an antenna in transmission) and / or the RF receiver (for a receiving antenna) is (are) electrically connected on the one hand to the monopoly 21 by a first power supply cable (positive pole) and on the other hand to the ground plane 22 by a second power cable (negative pole).
• a coaxial cable can be used for the power cable.
• the part of the monopoly 21 which appears superimposed on the ground plane 22 in FIG. 2 is in fact slightly raised compared to the ground plane 22, in other words the monopoly 21 is not directly in contact with the plane mass 22.
• An impedance matching circuit can be added, for example at the connection of the monopoly 21 with the source or the RF receiver.
• the parasitic cell 23 is formed by a printed ribbon in the form of an open loop.
• open loop is meant that the tape forms a loop, but that the two ends of the tape do not touch. In other words, an opening is made in the loop.
• the loop takes the form of a rectangle. It should however be noted that other shapes are possible for the parasitic cell 23.
• the loop can also take the form of an oval ring (see Figure 3), the shape of the letter D (see figure 4), or the shape of a semi-circle or a semi-oval with a rectilinear portion to partially close the semi-circle or the semi- oval (see Figure 5). In all cases, an opening should be left in the buckle.
• the parasitic cell 23 takes the form of a Z resonator rather than the form of an open loop.
• the radiator element 20 corresponds to an NFRP resonator (acronym for "Near-Field Resonant Parasitic") using a capacitive loop (NFRP antenna of the CLL type, acronym for "Capacitively Loaded Loop”).
• the parasitic cell 23 is placed in the near field of the monopoly 21.
• the monopoly 21 has a capacitive behavior and is indirectly adapted by the parasitic cell 23 which in turn has an inductive behavior.
• a resonant circuit of the LC type is thus obtained, by a phenomenon of coupling by evanescent waves in the near field between the monopoly 21 and the parasitic cell 23, which results in the propagation of a wave in the far field.
• Such a radiator element 20 has the advantage on the one hand of presenting a unitary radiation pattern oriented in the axis of the array 12 of the antenna 10, that is to say in the direction 13 in which it is desired to obtain the maximum gain (which contributes to the good directivity of the antenna 10 in this direction 13), and on the other hand to include a ground plane 22 (the advantage linked to the presence of the ground plane 22 will be discussed later in the description).
• the use of such a radiator element 20, different from the parasitic elements 30, makes it possible to obtain very good performance not only in terms of directivity, but also in terms of radiation efficiency.
• the antenna 10 has a directivity greater than 8 dBi and an output efficiency greater than -3 dB, which means that more than 50% of the power injected into the antenna 10 is radiated. by antenna 10.
• a similar antenna for which the radiator element 20 would be formed by an electric dipole identical to the parasitic elements 30 has a directivity which is only slightly better of the order of 9 dBi, but a radiation efficiency of less than -15 dBi, which means that less than 5% of the power injected into the antenna is radiated.
• the monopoly 21 is arranged on the face of the printed circuit board 11 opposite to the face on which the parasitic cell 23 is arranged. However, nothing prevents the monopoly 21 and the parasitic cell 23 from being arranged. on the same face of the printed circuit board 11. Thus, in particular embodiments, all the elements of the network 12 of the antenna 10 can be arranged on the same face of a printed circuit board.
• the monopoly 21 and the parasitic cell 23 are each arranged on a different face of the printed circuit board 11, as shown in Figures 1 and 2, the coupling between these two elements is mainly of an electrical nature.
• the coupling between these two elements is mainly magnetic in nature. It is advantageous, in terms of size, that the monopoly 21 and the parasitic cell 23 are each arranged on a different face of the printed circuit board 1 1, because they can then be superimposed, as shown in Figures 1 and 2.
• the antenna 10 described above with reference to Figures 1 and 2 is an antenna 10 for a receiving device used to geolocate connected objects emitting radio signals.
• the working frequency is at 869.5 MHz
• the receiving device must have sufficiently small dimensions for the receiving device to fit in the hand of a user, in the manner for example of a TV remote control.
• the searched for connected objects recurrently emit radio signals at the working frequency, and the user can move and point the receiving device in different directions in space to attempt to detect a signal emitted by an object.
• the antenna should therefore have a strong directivity to accurately detect the direction in which a detected object is located, as well as good radiation efficiency to increase the distance of detection of an object by the receiving device.
• the printed circuit board 1 1 on which the antenna 10 is made has a length of 165 mm and a width of 50 mm.
• the various radiating elements monopoly 21 and parasitic cell 23 of the radiator element 20, parasitic elements 30
• the two layers of the ground plane 22 are printed on the printed circuit board 1 1 in the form of a layer of copper 18 ⁇ m thick.
• each branch of the electric dipole has a total length of 96 mm and a width of 2 mm.
• the monopoly 21 has a length of 11 mm and a width of 1 mm.
• Each layer of the ground plane 22 is a rectangle 48 mm long and 18 mm wide.
• the loop of the parasitic cell 23 is formed by a tape 2 mm wide forming a rectangle 47 mm in length and 18 mm in width.
• the inter-element distance has been carefully studied so as to obtain the best possible compromise between size and coupling.
• This distance is particularly small relative to the inter-element distance generally observed in a conventional network (where it is typically of the order of half a wavelength at the working frequency).
• This small distance is necessary to obtain the “super-directive” behavior.
• the closer the elements of the network 12 are to each other the more one tends towards a theoretical directivity of the antenna 10 of the order of N 2 , where N is the number of elements in the network 12.
• N is the number of elements in the network 12.
• the smaller the inter-element distance the more the coupling between the elements is increased, which has a negative effect on the efficiency of the network 12. An acceptable compromise must therefore be reached between directivity and efficiency.
• the geometry of the antenna 10 was frozen, it was simulated, in a conventional manner, with electromagnetic simulation software to obtain the unit radiation patterns and the parameters S of the network 12 (from the English “Scattering parameters ”, These are the distribution coefficients to describe the electrical behavior of an antenna element as a function of input signals).
• the radiation patterns and the S parameters were then processed by an algorithm to determine the complex weight to be applied to each parasitic element 30 to optimize the directivity of the antenna 10 in a given direction.
• An approach of the “curve fitting” type was used, in which one seeks to minimize the difference, in the sense of least squares, between an ideal template and the diagram actually obtained by applying the weights. complex.
• the radiation pattern of the antenna 10 obtained is a linear combination of the different unit patterns. This is the sum of the unit diagrams of the various antenna elements of the array 12 weighted respectively by their complex weight.
• FIG. 7 schematically represents a radiation pattern at 869.5 MHz of the antenna 10 previously described with reference to FIGS. 1 and 2 when the phase shift circuit 34 of the director element 32 furthest from the radiator element 20 consists in a capacitor C2 of value 15 pF, the phase shift circuit 34 of the directing element 32 most close to the radiator element 20 consists of a capacitor C3 of value 10 pF, and the phase shifting circuit 34 of the reflector element 31 consists of a capacitor C4 of value 8.2 pF.
• the directivity of the antenna 10 is represented by the curve 41.
• the directivity in the direction 13 assumes a satisfactory value, greater than 8 dBi.
• front / back ratio is not optimal since a relatively large secondary lobe exists in the direction opposite to the direction of the main lobe.
• front / rear ratio is meant the ratio between the directivity in the direction 13 towards the front of the antenna 10 and the directivity in the opposite direction towards the rear of the antenna 10.
• a parametric study with the electromagnetic simulation software has shown that by taking a value of 8.2 pF for the capacitor C3 of the phase shift circuit 34 of the director element 32 closest to the radiator element 20, it is possible to increase the front / rear ratio by about ten dB without significantly degrading the directivity of antenna 10 (the latter going from 8.75 dBi to 8.25 dBi).
• the front / rear ratio is greater than 20 dB.
• the corresponding radiation pattern is shown in Figure 8.
• the directivity of antenna 10 is shown by curve 42 on this diagram.
• capacitors C2, C3 and C4 are surface mounted ceramic capacitors (SMD type components for "Surface Mounted Component", or SMD for "Surface Mounted Device”).
• FIG. 9 schematically represents a layer of the ground plane 22 of the radiator element 20 of the antenna 10. As illustrated in the figure
• holes that is to say zones 25 without copper are provided within the ground plane 22.
• tracks 26 and pads 27 of copper electrical circuit are printed. by screen printing, in a conventional manner, on the printed circuit board 1 1 on which the antenna 10 is produced.
• the tracks 26 form a copper path making the electrical interconnection between the electronic components which will be soldered at the level of the pads 27.
• the largest dimension of a zone 25 without copper is negligible compared to the wavelength of the working frequency of the antenna 10, for example the largest dimension of a zone 25 without copper does not exceed a tenth of the wavelength of the working frequency of the antenna 10.
• Such arrangements make it possible to guarantee that the ground plane 22 correctly plays its role within the radiator element 20 even if a part of the plane of mass 22 is used to accommodate electronic components of the receiving device.
• the ground plane 22 comprises two layers of copper (one layer on each side of the printed circuit board 11 on which the antenna 10 is made) connected by vias. Only one layer of the ground plane 22 is shown in FIG. 9. Electronic components can be arranged on one of the two layers, or else on the two layers of the ground plane 22. None prevents either, as indicated previously, that the ground plane 22 has only one layer.
• electronic components of the receiving device can be arranged on another printed circuit board than the printed circuit board 1 1 on which the antenna is made
• the printed circuit board on which electronic components of the receiving device are arranged can advantageously be positioned facing the ground plane 22, at a small distance from the ground plane 22, for example a few millimeters. only.
• the ground plane 22 advantageously makes it possible to shield any electromagnetic disturbances generated by the electronic components of the receiving device. Such electromagnetic disturbances would in fact be liable to disturb the operation of the antenna 10.
• the present invention achieves the objectives set.
• the antenna 10 exhibits very good performance both in terms of directivity, radiation efficiency and compactness.
• the antenna according to the invention also has the possibility of integrating the electronic components of the receiving device either directly on the ground plane 22 of the antenna 10, or on a printed circuit board positioned opposite and close to the ground plane 22 of the antenna 10. This contributes to limiting the dimensions of the receiving device, while avoiding disturbing the performance of the antenna.
• the invention has been described by considering an antenna 10 for a reception device having the objective of locating connected objects emitting radio signals. However, following other examples, nothing excludes considering other applications.
• the antenna 10 can be perfectly adapted to a transmitter device, or to a transmitter-receiver device.
• parasitic elements 30 for an antenna 10 can be considered for other choices. The same goes for the number of guiding elements and the number of reflective elements. In particular, nothing prevents having parasitic elements 30 of different sizes, for example director elements 32 shorter than the reflector element (s) 31.
• the parasitic resonator antenna corresponding to the radiator element 20 can be produced in different ways.
• the parasitic cell 23 can take different forms, the ground plane 22 can have only one layer instead of two, etc. These different choices only represent variants of the invention.
• the array 12 of elements of the antenna 10 has a length less than 200 mm and a width less than 100 mm (or even a length less than 165 mm and a width less than 50 mm) for a working frequency less than 1 GHz (especially, working frequency is 869.5 MHz).
• the antenna 10 has a maximum directivity value greater than 8 dBi and a radiation efficiency greater than 50%. In variants of the invention, another working frequency, and other dimensions of the antenna 10 are obviously possible. Different values of directivity and radiation efficiency could then be obtained.

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• Aerials With Secondary Devices (AREA)
• Variable-Direction Aerials And Aerial Arrays (AREA)

Applications Claiming Priority (2)

Publications (3)

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• 2019
  • 2019-03-19 FR FR1902798A patent/FR3094142B1/fr active Active
• 2020
  • 2020-03-16 US US17/431,417 patent/US20220336949A1/en not_active Abandoned
  • 2020-03-16 WO PCT/EP2020/057049 patent/WO2020187821A1/fr unknown
  • 2020-03-16 ES ES20710525T patent/ES2966228T3/es active Active
  • 2020-03-16 EP EP20710525.5A patent/EP3942649B1/de active Active

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