EP3756238A1

EP3756238A1 - Antenna system

Info

Publication number: EP3756238A1
Application number: EP19712036.3A
Authority: EP
Inventors: Daniele Piazza; Mauro FACCO
Original assignee: Adant Technologies Inc
Current assignee: ADANT TECHNOLOGIES Inc
Priority date: 2018-02-23
Filing date: 2019-02-21
Publication date: 2020-12-30
Anticipated expiration: 2039-02-21
Also published as: WO2019162883A1; IT201800002979A1; EP3756238B1; EP3756238C0

Abstract

The invention is an antenna system (1) comprising: at least one active radiating member (2) designed to emit and receive an electromagnetic signal (E) with frequency (fE) included between 100KHz and 100THz; at least one substantially laminar parasitic member (5) designed to be positioned peripherally with respect to the active member (2) and provided with two or more conductive sections (6, 7, 8, 9) having predetermined shape and length and configured to be selectively coupled with the radiating member (2) in such a way as to vary the directivity and the radiation pattern of the electromagnetic field emitted by the system; a plurality of switching devices (13) associated with the conductive sections (6, 7, 8, 9) to selectively connect the conductive sections (6, 7, 8, 9) to a reference potential (P) and promote their selective coupling with the active member (2); an electronic control unit (8) designed to selectively power the active member (3) with a predetermined electric signal and to control the status of the switching devices (13). The active member (2) is configured to emit an electromagnetic signal with frequency included within an operating band (B) whose width exceeds 5% of the frequency (fE ') of the electric signal with which it is powered, the conductive section (6, 7, 8, 9) formed in the parasitic member (5) is configured to be coupled with the active member (2) when the frequency (fE) of the electromagnetic signal (E) emitted by the latter is included in a respective predetermined sub-band (B1, B2,...) of the operating band (B).

Description

ANTENNA SYSTEM

DESCRIPTION

Field of application of the invention

[001 ] The present invention concerns the technical sector of telecommunications and antennas and the subject of the invention is an antenna system designed to promote the transmission of information through the emission of an electromagnetic field.

State of the art

[002] As is known, in the last years the sector of telecommunications has become one of the most advanced sectors in terms of technological progress.

[003] More specifically, the need to transmit a large quantity of data in increasingly shorter time frames has led to an increase in the technical evolution of many electronic devices used in the telecommunications sector, such as, for example, modulators, transmitters, receivers, amplifiers, filters, etc.

[004] In the last years these devices have been designed to process signals having increasingly higher frequency and to ensure rated operation within an increasingly higher frequency band.

[005] Today it is not unusual to find on the market devices that make it possible to process signals with frequency included between a few dozens Kilohertz and a few dozens Terahertz.

[006] Even the technical sector of antennas has benefited from this technological progress, since the antenna is a fundamental component for the transmission of data without the use of wires, fibres or other concentrated physical means.

[007] In view of the strong miniaturization that characterizes the telecommunications sector every day more, the antenna, like all the other components, must have a minimum size and be configured to operate also with frequencies belonging to different bands, so that the same component can transmit data intended for different services.

[008] For example, the antennas used in the automotive sector (FM/GPS/GSM) or in WiFi modems (2,4GHz - 5GHz) are typical examples of this type of component.

[009] In addition to being able to operate with frequencies belonging to different bands, last generation antennas are also capable of adapting their directivity according to the demand, in order to constantly ensure an optimal performance level.

[0010] In practice, antennas of this type can be reconfigured, which means that their behaviour can be adapted to the intended use in order to guarantee the maximum directivity possible in all conditions.

[001 1] The patent US 9,263,798 granted to Adant Technologies, Inc. describes a radiating system made up of a grounding screen, a plurality of first and second active radiating members designed to emit an electromagnetic signal with a predetermined frequency, a plurality of parasitic members configured to selectively resonate with the first or with the second antennas and a plurality of switching devices designed to connect the parasitic members in such a way as to promote the coupling of the latter with the first or the second antennas.

The selective coupling of one or more parasitic members makes it possible to vary the system’s radiation pattern and thus to modify the directivity of the beam according to the needs.

This system comprises also an electronic control unit designed to selectively vary the condition of the switching devices in order to promote the selective coupling of the parasitic portions.

[0012] A first drawback posed by this solution lies in that the first and the second active radiating members are configured to emit an electromagnetic field at two different discrete frequencies, typically close to 2,4GHz and 5GHz.

[0013] This special configuration limits the field of application of the radiating system, since the entire transmission and reception chain must be centred exclusively on these two reference frequencies and this does not allow signals with frequency falling within bands that are different from those indicated above to be transmitted or received.

[0014] Furthermore, the behaviour of the antenna is particularly directive in correspondence with the reference frequencies, while this parameter declines considerably already in the range of said frequencies.

[0015] A further drawback posed by these configurations lies in that the electrical operating characteristics of the radiating system remain such as to correspond to the design values only when the transmitted/received signals are included within a very narrow band centred on the reference frequencies.

[0016] It can thus be affirmed that these radiating systems are optimized to operate in a substantially monochromatic frequency regime and this represents a strong limit for all the applications where it is necessary to emit and receive signals belonging to different frequency bands using a single device.

[0017] The drawbacks described above can be found also in the antenna systems described in the patent documents US7,088,306 - US2003/210204 - US2002/0244468. These systems, in fact, are designed to emit and/or receive monochromatic electromagnetic signals centred on specific discrete frequencies and therefore have the same limits as the system described in the above mentioned document US9,263,798. Description of the invention

[0018] The present invention aims to overcome the drawbacks illustrated above by providing an innovative antenna system.

[0019] More specifically, the main object of the present invention is to provide an antenna system configured to emit and receive electromagnetic signals whose frequency can vary continually within a predetermined frequency band.

[0020] It is a further object of the present invention to provide an antenna system that makes it possible to emit and receive electromagnetic signals that have a predetermined and relatively large bandwidth, are not of the monochromatic type and are centred on discrete frequencies.

[0021] It is another object of the present invention to provide an antenna system that is capable of receiving and transmitting electromagnetic signals whose frequency falls within several distinct bands.

[0022] It is a further object of the present invention to provide an antenna system with high directivity of transmission and reception of the electromagnetic signal, even when the frequency of the latter is not monochromatic and varies, even continually, within a predetermined band.

[0023] It is another, yet not the least object of the present invention to provide an antenna system capable of ensuring that the design specifications remain substantially constant even when it transmits and receives electromagnetic signals which are not monochromatic and whose frequency varies within one or more predetermined widthbands.

[0024] These objects, together with others that are highlighted in greater detail below, are achieved by an antenna system of the type described in claim 1 .

[0025] Other objects that are better described below are achieved by the radiating system according to the invention carried out as described in the dependent claims. Brief description of the drawings

[0026] The advantages and characteristics of the present invention are clearly illustrated in the following detailed description of some preferred but non-limiting embodiments of an antenna system of the type described, with particular reference to the following drawings, wherein:

- Figures 1 A and 1 B respectively show a perspective view and a top view of an antenna system according to the invention in a first configuration;

- Figures 2A, 2B and 2C respectively show two perspective views and a top view of an antenna system according to the invention in a second configuration;

- Figures 3A, 3B, 3C and 3D refer to a third configuration of an antenna system according to the invention and more specifically they show two perspective views, an exploded perspective view of a first detail of said system and a complete exploded view;

- Figure 4 shows a schematic perspective view of an antenna system according to the invention in a second configuration;

- Figures from 5 to 9 are radiation patterns of the system shown in Figures 3A - 3D, respectively at the frequencies 810MHz, 910MHz, 1860M Hz, 2140MHz and 3550MHz.

Detailed description of the invention

[0027] The subject of the present invention is an antenna system, indicated by the reference number 1 here below and designed to be used in a telecommunications system in order to emit or receive electromagnetic signals with which a plurality of numerical data are associated.

[0028] More specifically, the antenna system 1 comprises at least one active radiating member 2 designed to emit and receive an electromagnetic signal E with predetermined frequency ίe.

[0029] The active member 2 is configured to emit and receive a signal E within a wide frequency band, typically included between 100KHz and 100THz.

[0030] As better illustrated in the Figures, the shape of the active member 2 is selected in such a way as to guarantee the transmission and reception of an electromagnetic signal E included within an operating band B of frequencies f_E with predetermined bandwidth, wherein the extreme values (bottom and top) of said bandwidth are in any case defined by the frequencies specified above.

[0031] Further on in this description, the terms“frequency band” and“bandwidth” are used as synonyms and indicate the value, expressed in Hertz, of the amplitude occupied by the frequency spectrum of a signal transmitted/received by the antenna system.

[0032] The system 1 will be configured to emit and/or receive an electromagnetic signal E whose spectrum can partially or completely occupy the operating band B or whose frequency varies over time in such a way as to“wipe” the operating band B, partially or completely.

[0033] The present antenna system is thus configured to emit electromagnetic signals E of the polychromatic type, meaning signals having variable frequency ίe and/or signals whose spectrum is included within a specific band B, differently from the known systems that are designed to work only with one (or maximum two) discrete monochromatic frequencies.

[0034] For example, the active member 2 of the system 1 shown in Figures 1A and 1 B has a pointed shape and a substantially hexagonal cross section.

[0035] The active members 2 of the system represented in Figures 2A- 2C have a more complex geometric shape including, in particular, a substantially triangular base 3 defining a longitudinal development axis L connected to a substantially transverse L- shaped expansion 4.

[0036] The geometric shape selected for the active members 2 of the system represented in Figures 3A - 3D is even more complex, in fact said active members 2 are provided with a base 3 similar to that used in the previous configuration, but provided with one pair of corresponding transverse extensions 4 arranged in a position in which they are rotated by 180°.

[0037] These special shapes of the active member are selected in such a way as to maximize some electrical parameters that are typical of antennas (directivity, gain, impedance, etc.) within the operating band B.

[0038] The shape of the active member 2 is selected in such a way as to promote the emission of an electromagnetic field E designed to propagate mainly along a substantially longitudinal direction L.

[0039] In the configurations of the invention illustrated in the Figures there are also several active members 2 that can be used individually or in pairs.

[0040] These active members 2 are configured to emit and receive a signal E with frequency ίe included between approximately 700M FIz and approximately 3600MFIz.

[0041] Conveniently, the operating band B of the signal E emitted by the active member 2 can have a width BW not smaller than 5% of the frequency ίe’ of the signal emitted/received by the active member 2 in that precise instant.

[0042] For example, if the active member 2 is emitting a signal with frequency ίe’ equal to 1000MHz, the width BW of the band B will not be less than f0.05 = 50MHz.

[0043] Furthermore, in most cases said band B will be centred on the frequency f_E’.

[0044] There is at least one substantially laminar parasitic member 5 designed to be positioned peripherally with respect to the active member 2.

[0045] Each parasitic member 5 is provided with two or more conductive sections 6, 7, 8, 9 having predetermined shape and length.

[0046] The shape and length of the conductive sections 6, 7, 8, 9 are selected in such a way as to promote, in particular circumstances that are described in greater detail below, the selective electromagnetic coupling of the same conductive sections 6, 7, 8, 9 with the active member 2 in order to vary the directivity and the radiation pattern of the electromagnetic field E emitted by the system.

[0047] In other words, when the active member 2 is emitting a signal E included in the band B, it will be possible to selectively couple one or more parasitic members 5 in such a way that the conductive sections 6, 7, 8, 9 formed in the latter can be electrically coupled with the active member.

[0048] In the present description, the term “coupling” is used to describe the electromagnetic resonance phenomenon that can occur between two conductive bodies physically separated from each other.

[0049] The coupling that takes place between the active member and the conductive sections makes it possible to perform a dynamic change of the overall electric configuration of the system 1 , allowing its directivity and radiation pattern to be modified.

[0050] In the configuration of the system illustrated in Figures 1A and 1 B, there are two parasitic members 5, each one of which has two respective conductive sections 6, 7.

[0051] In this case, each conductive section 6, 7 is defined by respective conductive strips 6’, 7’ electrically connected to corresponding solid conductive areas 6”, 7” that in this specific case are substantially in the shape of a triangle and of a rectangle.

[0052] In the configuration of the system illustrated in Figures 2A - 2C there are three parasitic members 5 designed to be coupled with a corresponding active member 2.

[0053] In this case, each parasitic member 5 is provided with three conductive sections 6, 7, 8 formed therein, which are defined by strips 6’, 7’ and by solid polygonal areas 8’, in a manner similar to that described with reference to the previous example.

[0054] In the configuration of the system illustrated in Figures 3A - 3D each active member 2 is associated with four parasitic members 5, whose sections 6, 7, 8, 9 were obtained using conductive strips 6’, 7’, 8’, 9’; 6”, 7”, 8”, 9” having predetermined length and shape. In this specific case, each conductive section is constituted by at least one longitudinal strip 6’, 7’, 8’, 9’ and at least one transverse strip 6”, 7”, 8” joined in correspondence with the level of a respective end.

[0055] As already described above, the antenna system 1 that is the subject of the present invention may comprise, in its minimum configuration, a single active member 2 and a single parasitic member 5; however, it is evident that this system can use a total number of active members and parasitic members greater than one and in any case different from that visible in the illustrated configurations.

[0056] The number of the active members 2 and of the parasitic members 5, respectively, can vary according to the field of application of the system and to the desired directivity and electromagnetic pattern values.

[0057] For example, in the preferred configuration of the invention illustrated also in Figures 2A - 2C and 3A - 3D, the system 1 comprises at least one pair of active radiating members 2 and at least two pairs of parasitic members 5, each pair being configured to be selectively coupled with a corresponding active member 2.

[0058] Conveniently, the phase centre C associated with each conductive section is positioned at a predetermined distance di, d₂ from the active member 2 and said distance di, d₂ varies according to the frequency ίe of the electromagnetic signal E that can be emitted by the latter.

[0059] The expression“phase centre” indicates the specific analytic point associated with each conductive section, from which an imaginary spherical wave propagates in far field conditions (the so-called Fraunhofer region).

[0060] In the context of the present invention, the expression“phase centre” is also meant to define a sort of“electrical centre of gravity” of each conductive section 6, 7, 8, 9, indicating in this regard a hypothetical point in which it is possible to concentrate the structure of the same while at the same time maintaining its electric and electromagnetic behaviour unchanged.

[0061] As better illustrated in the Figures, the distance di, d₂ that separates the phase centre of each conductive section 6, 7, 8, 9 from the corresponding active member 2 decreases as the frequency ίe of the signal E emitted by the same member increases.

[0062] Consequently, the conductive section 6, 7, 8, 9 nearest to the active member is configured to resonate at a higher frequency compared to that of the furthest conductive section 6, 7, 8, 9.

[0063] In the configurations illustrated in Figures from 2A to 3D, the parasitic member 5 comprises a first laminar portion 10 including the conductive sections 6, 7 designed to be coupled with the active member 2 when the latter emits signals E with predetermined frequencies ίe” included in the band B, and a second laminar portion 1 1 including the conductive sections 8, 9 designed to be coupled with the active member 2 when the latter emits signals E with frequencies f_E’” (f_E’” > ίe”) that are higher but still falling within the same band B.

[0064] As better illustrated in Figure 3C, fixing means 12 can be provided, which are obtained in the first portion 10 and in the second portion 1 1 and are designed to promote the removable connection of the same, in such a way as to obtain a unitary parasitic member 5.

[0065] The installation of this unitary parasitic member 5 will make it possible to position the first portion 10 at a distance di from the active member that is greater than the distance d₂ that separates the second portion 11 from said active member 2.

[0066] Preferably, the first portion 10 of each parasitic member 5 can be arranged correspondence with the sides of a regular polygon, for example a square, a pentagon, a hexagon, etc.

[0067] The sides of said polygon, in any case, will all be positioned at the same distance di from the active member 2.

[0068] This arrangement of the first portion 10 will thus make it possible to position the phase centres C of the conductive sections 6, 7 formed in the first portion 10 at respective differentiated distances di’, di” from the active member 2.

[0069] Also the phase centres C of the conductive sections 8, 9 formed in the second portion 11 are positioned at differentiated distances d₂’, d₂” from the active member 2.

[0070] As already described above, the distances d₂’, d₂” of the conductive sections 8, 9 formed in the second portion 11 are shorter than the distances di’, di” of the conductive sections 7, 9 formed in the first portion 10.

[0071] According to a peculiar aspect of the invention, each conductive section 6, 7, 8, 9 is configured to be coupled with the active member 2 when the frequency ίe of the electric signal emitted by the latter is included within a respective sub-band B’ of the operating band B (B’<B).

[0072] More specifically, the shape and size of the conductive sections 6, 7, 8, 9 formed in the corresponding parasitic members 5 can be selected in such a way that they can be coupled with the active member 2 when the latter emits an electromagnetic frequency signal respectively included in a first group of sub-bands Bi or in a second group of sub bands E¾2.

[0073] More specifically, the selective coupling of the active member 2 with the corresponding conductive sections 6, 7, 8, 9 can take place during the emission or reception of non-monochromatic electromagnetic signals E whose bandwidth is included within the respective sub-band Bi, Bi’.

[0074] The union of the first group of sub-bands Bi and the second group of sub-bands B₂ can correspond to the operating bandwidth BW (B = Bi + B₂) or can be smaller than said band B and the frequency of the first group of sub-bands Bi is lower than the frequency of the second group of sub-bands B₂ (Bi < B₂).

[0075] Conveniently, the conductive sections 6, 7 of the first portion 10 can be configured to be coupled with the active member 2 when the latter emits an electromagnetic signal E with frequency ίe included in the first group of sub-bands Bi, while the conductive sections of the second portion 1 1 can be configured to be coupled with the active member 2 when the latter emits an electromagnetic signal E with frequency ίe included in the second group of sub-bands B₂.

[0076] In general, the antenna system according to the invention can be provided with an active radiating member 2 designed to emit a polychromatic electromagnetic signal E whose spectrum is distributed within the operating band B and with two or more parasitic members 5, each one of which has conductive sections 6, 7, 8, 9 especially sized to resonate in a specific sub-band Bi and B₂.

[0077] For example, the sub-band B₂ will include higher frequencies than those contained in the sub-band Bi (Bi < B₂), even if both of these sub-bands Bi and B₂ are contained within the operating band B.

[0078] As better illustrated in Figures from 3A to 3D, in the case of a system 1 with operating band B included between 700MFIz and 3600MFIz, the section 6 of the first portion having greater extension can be configured to be coupled with the active member 2 when the frequency of the emitted signal E is included in a sub-band of the first group Bi =700MHz-960MHz.

[0079] The other section 7 formed in the first portion and having smaller extension can be configured to be coupled with the active member 2 when the frequency of the emitted signal E is included in a higher sub-band of the first group Bi’ = 1600MHz- 2100MHz.

[0080] The conductive section 8 formed in the second portion and having substantially the shape of an“L” can be configured to be coupled with the active member 2 when the latter emits a frequency signal included in a sub-band of the second group B₂ = 2200MHz-2700MHz, while the other conductive section 9 formed in the second portion 11 can be configured to be coupled with the active member 2 when the latter emits a frequency signal included in a higher sub-band of the second group B₂’ = 3400-3600M Hz.

[0081] Even in this case, the coupling between the active members 2 and a single parasitic conductive section 6, 7, 8, 9 can take place for the signals E whose spectrum partially (or completely) occupies the corresponding sub-band of the first group Bi, Bi’ or of the second sub-group B₂, B₂’.

[0082] Conveniently, the system comprises a plurality of switching devices 13 associated with the conductive sections 6, 7, 8, 9 of at least one parasitic member 5 to selectively connect it to a predetermined reference potential P and promote its selective coupling with the active member 2.

[0083] An electronic control unit 14 is also provided, which is respectively designed to power the active member 2 with a signal E with frequency ίe included between 100KHz and 100Thz and to control the status (ON=closed/OFF=open) of each single switching device 13.

[0084] The switching devices 13 and the electronic control unit 14 are both visible in Figure 1A, in a schematic view, and in Figure 3B.

[0085] When the electronic control unit 14 promotes the closing of a switching device 13 (bringing it to status ON), the reference potential P is applied to the respective conductive section 6, 7, 8, 9 associated with it, and the application of this voltage allows the said section to enter into resonance with the active member 2 at the frequency f_E of the electromagnetic signal E emitted by the latter.

[0086] On the contrary, when the electronic control unit 14 promotes the opening of the switching device 13 (maintaining it in status OFF), the respective conductive section 6, 7, 8, 9 is brought to a potential different from the reference potential P.

[0087] In this special condition, the section is “neutral” with respect to the electromagnetic signal E emitted by the active member 2, meaning that no resonance takes place between these two components and the conductive part of the section does not interfere with the emitted signal E.

[0088] Conveniently, the reference potential P can be null and thus the system 1 may comprise an electric ground 15 obtained on a substantially laminar support layer 16 to which the active radiating member 2, the parasitic member 5 and the plurality of switching devices 13 are anchored.

[0089] In general, by varying the status of the switching devices 13 it will be possible to promote the coupling of the conductive sections 6, 7, 8, 9 of each parasitic member 5 in such a way as to promote the selective resonance of said sections with the active member 2 in the respective sub-bands Bi or B₂, as already described in paragraphs [0076] - [0083]

[0090] More specifically, as shown in greater detail in Figure 3B, the switching devices 13 can be made up of diodes having a terminal 17 connected to the respective conductive section 6, 7, 8, 9 and the other terminal 18 connected to the electric ground 15 obtained on the lower surface 19 of the support layer 16.

[0091] The switching of the diodes thus makes it possible to selectively connect the respective conductive section 6, 7, 8, 9 to the ground 15 with null potential.

[0092] In the configuration of the invention illustrated in Figures from 2A to 3D, the conductive sections 6, 7, 8, 9 of each parasitic member 5 are connected to six diodes, four of which associated with the first portion 10 and the remaining two associated with the second portion 11.

[0093] As a result, said system 1 has twenty-four diodes selectively controlled by the electronic control unit 14, so as to couple the respective sections 6, 7, 8, 9 with a single active member 2.

[0094] Preferably, as better visible in the configuration of the invention illustrated in Figures from 3A to 3D, each section 6, 7, 8, 9 can have a free end 20 designed to be anchored to the support layer 16.

[0095] The latter, in fact, is provided with a plurality of slits 21 designed to allow the insertion of the corresponding free ends 20 of the conductive sections 6, 7, 8, 9.

[0096] For example, each conductive section 6, 7, 8, 9 may comprise one pair of associated free ends 20 designed to be inserted in corresponding slits formed in the laminar support layer 16.

[0097] The switching devices 13 can be positioned correspondence with said free ends 20 once the latter have been inserted in the slits 21. [0098] More specifically, as schematically illustrated in Figure 3B, a terminal 17 of the diodes 13 can be welded to the free end 20 of the section 6, 7, 8, 9, while the other terminal 18 can be welded to the electric ground 15.

[0099] Furthermore, it is preferable to use a capacitive member 22 interposed between the conductive sections 6, 7, 8, 9 to stop the flow of a direct current that, if necessary, may flow along an electric path K comprising one pair of free ends 20 associated with said sections 6, 7, 8, 9.

[00100] As better illustrated in Figures 3B and 3C, the capacitive members 22 can be interposed between two branches of the transverse conductive strip 6”, 7” that defines the sections 6, 7 formed in the first portion 10 of the parasitic member 5, configured so that they can be coupled with the active member 2 when the latter emits a signal with frequency ίe included in the first group of sub-bands Bi.

[00101 ] In order to increase the directivity of the signal emitted by the active member 2 it is possible to position further metallic elements 23, 24 having a predetermined shape around said active member 2.

[00102] Said elements 23, 24 are configured to be coupled with the active member 2 substantially for all the frequencies falling within the operating band B.

[00103] Following several experimental tests, it has been possible to verify that the use of two substantially annular metallic elements 23, 24, positioned in such a way as to surround the active member completely, brings considerable benefits in terms of beam directivity.

[00104] It is possible to further optimize the directivity of the system 1 by shaping said annular elements 23, 24 substantially as a hexagon and arranging said components around the active member 2 in a substantially concentric position.

[00105] In the configuration of the invention illustrated in Figure 4 it is possible to observe an electronic component indicated with the reference number 25 and generally consisting of an inductor. This component 25 is mounted on a corresponding conductive section 6” of the parasitic member 5 that is designed to resonate with the active member 2 in the lower sub-band Bi.

[00106] The application of this electronic component 25 makes it possible to vary the electromagnetic behaviour of the corresponding conductive section 6” when the electromagnetic signal E emitted by the active member 2 has a frequency ίe that is higher than a predetermined value f_H. In other words, the presence of this component 23 makes it possible to inhibit the resonance of the conductive section 6” with respect to signals E with frequency exceeding the predetermined value (ίe > ), in such a way as to make said section substantially electromagnetically inert for frequencies higher than f_H.

[00107] The electronic component 23 thus has the function of permitting the resonance of the conductive section 6” in the corresponding lower sub-band Bi, at the same time ensuring its complete electromagnetic uncoupling (and consequent non-resonance) with respect to all the electromagnetic signals E whose frequency exceeds the sub-band B1.

[00108] Figures 4, 5 and 6 show the radiation patterns of the system when the active member emits an electromagnetic signal with frequency f_E respectively equal to 810MHz (Figure 4), 910M Hz (Figure 5), 1860M Hz (Figure 6), 2140M Hz (Figure 7) and 3550M Hz (Figure 8).

[00109] The system 1 may also comprise a transceiver device, not illustrated in the Figures, positioned on the support layer 16 and connected to the active member 2.

[001 10] With this configuration it will thus be possible to provide a system that integrates all the electronic components necessary to make a transceiver device.

[001 1 1 ] In this case, the electronic control unit 8 may comprise a processor, not illustrated in the Figures, either, which is connected to the transceiver device.

[001 12] Said processor, in addition to selectively controlling the opening and closing of the switching devices 13, can be programmed in such a way as to execute a plurality of instructions designed to promote the processing of the electric signals sent and received by the active radiating member 2 and of the numerical data associated with them.

[001 13] The present invention can be carried out in other variants, all of which fall within the scope of the inventive features claimed and described herein; these technical details can be replaced by different but technically equivalent components and materials; the invention can be carried out in any shapes and sizes, provided that they are compatible with its intended use.

[001 14] The reference numerals and signs added in the claims and the description are designed to make the text clearer to understand and must not be considered as elements designed to limit the technical scope of application of the objects or processes they are meant to identify.

Claims

1 . An antenna system (1 ), comprising:

- at least one active radiating member (2) designed to emit and receive an electromagnetic signal (E) with frequency (f_E) included between 100kHz and 100THz;

- at least one substantially laminar parasitic member (5) designed to surround said at least one active member (2) and provided with two or more conductive sections (6, 7, 8, 9) having predetermined shape and length, said two or more conductive sections (6, 7, 8, 9) being configured to be selectively coupled with said active radiating member (2) for varying the directivity and the radiation pattern of the electromagnetic field emitted by the radiating system;

- a plurality of switching devices (13) associated with said conductive sections (6, 7, 8, 9) of said at least one parasitic member (5), the switching devices (13) of said plurality being designed to selectively connect said two or more conductive sections (6, 7, 8, 9) to a predetermined reference electric potential (P) to promote the selective coupling of said conductive sections (6, 7, 8, 9) with said at least one active member (2);

- an electronic control unit (8) designed to selectively emit a predetermined electric signal to said at least one active member (3) and to control the status of said switching devices (13);

characterized in that:

- said active member (2) is configured to emit and receive an electromagnetic signal with a frequency spectrum included within an operating band (B) whose bandwidth exceeds 5% of the frequency (ίe') of the electric signal which supply to said active member (2) in real-time;

- each conductive section (6, 7, 8, 9) formed in said at least one parasitic member (5) is configured to be coupled with said at least one active member (2) when the frequency spectrum of the electromagnetic signal (E) emitted by the latter is distributed in a respective predetermined sub-band (B1 , B2) of said operating bandwidth (B).

2. System as claimed in claim 1 , characterized in that the phase centre (C) of each one of said conductive sections (6, 7, 8, 9) is located at a predetermined distance (di ; d₂) from said active member (2), said distance (di, d₂) being variable as a function of the frequency (f_E’) of the electromagnetic signal (E) emitted by said active member (2).

3. System as claimed in claim 2, characterized in that said distance (di ; d₂) decreases as the frequency (f_E’) of the electromagnetic signal (E) emitted by said at least one active member (2) increases.

4. System as claimed in claim 3, characterized in that said parasitic member (5) comprises two or more conductive sections (6, 7, 8, 9) configured to be coupled with said active member (3) when the frequency (f_E’) of the signal (E) emitted by said active member (2) is selected within a first group of sub-bands (Bi) or within a second group of sub-bands (B₂), the frequencies of said first group of sub-bands (Bi) being lower than the frequencies of said second group of sub-bands (B₂).

5. System as claimed in claim 4, characterized in that each parasitic member (5) has a first laminar portion (10) in which at least one conductive section (6, 7) is formed, said at least one conductive section (6, 7) being designed to be coupled with said at least one active member (2) when the frequency (f_E’) of the electromagnetic signal (E) emitted by the latter is included within said first group of sub-bands (B1 ), each first portion (10) being placed correspondence with the sides of a regular polygon, said sides being spaced substantially at the same distance (di) from said at least one active member (2).

6. System as claimed in claim 5, characterized in that each parasitic member (5) has a second laminar portion (1 1 ) in which at least one conductive section (6, 7) is formed, said at least one conductive section (6, 7) being designed to be coupled with said at least one active member (2) when the frequency (f_E ) of the electromagnetic signal (E) emitted by the latter is included within said second group of sub-bands (B2), said second portion (1 1 ) being spaced from said at least one active member (2) by a predetermined distance (d₂) that is shorter than the distance (di) that separates said at least one active member (2) from the sides of said polygon.

7. System as claimed in claim 1 , characterized in that it comprises a substantially laminar support layer (16) to which said at least one active radiating member (2), said at least one parasitic member (5) and said plurality of switching devices (13) are anchored.

8. System as claimed in claim 7, characterized in that the conductive sections (6, 7, 8, 9) formed in said plurality of parasitic members (5) comprise one end (20) designed to be anchored to said support layer (16), said switching devices (13) being positioned in correspondence with the level of said ends (20) to selectively connect the latter to said reference electric potential (P).

9. System as claimed in claim 8, characterized in that each conductive section (6,

7, 8, 9) formed in said plurality of parasitic members (5) comprises a pair of ends (20) with which a respective pair of switching devices (13) is associated, said electronic control unit (14) being configured to selectively activate a single switching device (13) of said pair in order to promote the electromagnetic coupling of the respective conductive section (6, 7, 8, 9) with said at least one active member (2) when the latter emits a signal with frequency included within a limited range of a band (Bi) of the first group or of a band (B₂) of the second group.

10. System as claimed in claim 8, characterized in that it comprises a capacitive member (22) mounted on at least one conductive section (6”, 6”) formed in said parasitic member (4) in order to block the circulation of a DC current along an electrical path (K) comprising one or both of the free ends (20) of said conductive sections (6”, 7”).

1 1. System according to claim 10, characterized in that it comprises an electric ground (15) formed in said support layer (16) and having a substantially null reference electric potential (P), said plurality of switching devices (13) being designed to selectively connect the conductive sections (6, 7, 8, 9) of at least one parasitic member (5) to said electric ground (15) in order to apply said null reference potential to said sections (6, 7,

8, 9).

12. System as claimed in claim 1 , characterized in that it comprises one pair of active radiating members (2) and at least two pairs of parasitic members (5), each pair of parasitic members (5) being designed to be selectively coupled with a predetermined active radiating member (2) of said pair.

13. System as claimed in claim 7, characterized in that it comprises a transceiver device positioned on said support layer (16) and connected to said at least one radiating active member (2).

14. System as claimed in claim 13, characterized in that said electronic control unit (8) comprises a processor connected to said transceiver device, a plurality of instructions being installed in said processor for promoting the processing of the electric signals transmitted and received by said at least one active radiating member (2) and of the numerical data associated with them.