WO2021171119A1 - Antenne active comprenant une antenne cadre blindée - Google Patents

Antenne active comprenant une antenne cadre blindée Download PDF

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Publication number
WO2021171119A1
WO2021171119A1 PCT/IB2021/051064 IB2021051064W WO2021171119A1 WO 2021171119 A1 WO2021171119 A1 WO 2021171119A1 IB 2021051064 W IB2021051064 W IB 2021051064W WO 2021171119 A1 WO2021171119 A1 WO 2021171119A1
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WO
WIPO (PCT)
Prior art keywords
active antenna
amplifier
transmission line
antenna
conductor
Prior art date
Application number
PCT/IB2021/051064
Other languages
English (en)
Inventor
Frédéric Broyde
Evelyne Clavelier
Original Assignee
Tekcem
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Tekcem filed Critical Tekcem
Publication of WO2021171119A1 publication Critical patent/WO2021171119A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q7/00—Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop
    • H01Q7/04—Screened antennas
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01Q—ANTENNAS, i.e. RADIO AERIALS
    • H01Q23/00—Antennas with active circuits or circuit elements integrated within them or attached to them
    • 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
    • H01Q5/20—Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements characterised by the operating wavebands
    • H01Q5/25—Ultra-wideband [UWB] systems, e.g. multiple resonance systems; Pulse systems
    • 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
    • H01Q5/307—Individual or coupled radiating elements, each element being fed in an unspecified way
    • H01Q5/314—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors
    • H01Q5/321—Individual or coupled radiating elements, each element being fed in an unspecified way using frequency dependent circuits or components, e.g. trap circuits or capacitors within a radiating element or between connected radiating elements

Definitions

  • Active antenna comprising a screened loop aerial
  • the invention relates to an active antenna comprising a screened loop aerial, for instance an antenna for radio communications and/or electromagnetic field measurements.
  • Loop aerials more commonly referred to as “loop antennas”, and screened loop aerials, more commonly referred to as “shielded loop antennas”, are well known to specialists. They are used for radio reception applied to electromagnetic field measurements, to direction finding and to radio communications. Some characteristics and limitations of these antennas for these uses are explained in the article of F. Broyde and E. Clavelier entitled “Contribution to the Theory of Planar Wire Loop Antennas Used for Reception”, published in the journal IEEE Transactions on Antennas and Propagation, vol. 68, no. 3, in March 2020. In particular, this article explains to what extent it is possible to consider that these antennas measure a component of an incident magnetic field, that is to say a magnetic component of an incident electromagnetic field.
  • the screen (also referred to as “shield”) of a screened loop aerial typically operates as a loop aerial.
  • Screened loop aerials used for radio reception provide better results than unscreened loop aerials, because they are not affected by a common-mode current flowing on the cable linking the antenna to a measuring instrument or a radio receiver, induced by an incident electromagnetic field received as a signal, or by electromagnetic disturbances.
  • a prior art active antenna comprising: a screened loop aerial, the screened loop aerial being a single-turn screened loop aerial, the screened loop aerial being small compared to said wavelength in vacuum, the screened loop aerial having a port, an impedance presented by this port being referred to as “impedance of the screened loop aerial”; an amplifier, the port of the screened loop aerial being coupled to an input of the amplifier, the input of the amplifier having an impedance referred to as “input impedance of the amplifier”, an absolute value of the input impedance of the amplifier being, at any frequency in the known frequency band, much less than an absolute value of the impedance of the screened loop aerial, an output voltage of the amplifier being, at a given frequency in the known frequency band, equal to the product of an input current of the amplifier and a transimpedance, an
  • the active antenna shown in Fig. 1 comprises: a first element (1), the first element being a transmission line having an outer conductor (11) and an inner conductor (12), the transmission line having a first end (101) and a second end (102), the outer conductor having a first end at the first end of the transmission line, the outer conductor having a second end at the second end of the transmission line, the inner conductor having a first end at the first end of the transmission line, the inner conductor having a second end at the second end of the transmission line, the first element being a part of the screened loop aerial; a second element (2), the second element being an electric conductor, the second element having a first end (201) and a second end (202), the first end of the second element being coupled to the first end of the inner conductor, the second element being a part of the screened loop aerial; a part referred to
  • a suitable amplifier may for instance be a transimpedance amplifier or a transresistance amplifier similar to the ones discussed in paragraph 8.11 of the book of P. Horowitz and W. Hill entitled “The Art of Electronics, Third Edition”, published by Cambridge University Press in 2015, or to the ones which are used in the patent of the United States of America number 5,352,984 entitled “Fault and splice finding system and method”, or in the international application number PCT/DE2006/000415 (WO 2006/097071) entitled “Active reception antenna system”.
  • first active antenna consisting of such a screened loop aerial and such an amplifier
  • second active antenna consisting of a loop aerial having the same size as the screened loop aerial, and of the same amplifier as the one used in the first active antenna
  • a first problem is that the least upper bound of the frequency band over which the antenna factor is substantially independent of the frequency is much lower for the first active antenna than for the second active antenna. To compensate this reduction, it is necessary to reduce the size of the screened loop aerial, which entails, at frequencies less than the least upper bound, an increase of the product of the antenna factor and the noise voltage density at the output of the active antenna (this density being expressed in r.m.s. volt per square root of hertz), whereas the designer wishes that this product is as small as possible at these frequencies.
  • the prior art does not disclose an active antenna comprising a screened loop aerial, the active antenna having an antenna factor which is substantially independent of the frequency in a known frequency band having a specified least upper bound, and the active antenna being such that, at frequencies less than the least upper bound, a product of its antenna factor and the noise voltage density at the output of the active antenna is small.
  • a second problem is that the first active antenna is easily disturbed by a radio signal at a frequency greater than the least upper bound, because the sensitivity of the screened loop aerial is much lower in the known frequency band, where the screened loop aerial is electrically small, than at some frequencies higher than the least upper bound, especially near some resonant frequencies of the screened loop aerial. If the active antenna is disturbed by a radio signal at a frequency greater than the least upper bound, desensitization and/or cross-modulation and/or intermodulation may occur.
  • the known solution to protect the first active antenna from a radio signal at a frequency greater than the least upper bound uses a low-pass filter inserted between the port of the screened loop aerial and the input of the amplifier.
  • Figure 2 shows a plot of the absolute value of an impedance of the screened loop aerial of the active antenna shown in Fig. 1, as a function of frequency.
  • the specialist understands that the impedance of the screened loop aerial and the input impedance of the amplifier are such that an effective low-pass filter introduces unwanted variations of the antenna factor as a function of frequency, which strongly reduce the least upper bound.
  • the prior art does not disclose an active antenna comprising a screened loop aerial, the active antenna having an antenna factor which is substantially independent of the frequency in a known frequency band having a specified least upper bound, the active antenna being not easily disturbed by a radio signal at a frequency greater than the least upper bound, and the active antenna being such that, at frequencies less than the least upper bound, a product of its antenna factor and the noise voltage density at the output of the active antenna is small.
  • the purpose of the invention is an active antenna, without the above-mentioned limitations of known techniques.
  • Coupled always refers to an electrical coupling.
  • “coupled” may indicate that the items are directly coupled, that is to say connected (or, equivalently, in electrical contact) to one another, and/or that the items are indirectly coupled, in which case an electrical interaction different from direct coupling exists between the items, for instance through one or more components.
  • Coupled When applied to two multi-terminal items, such as ports, connectors, etc, “coupled” may indicate that the items are directly coupled, in which case each terminal of one of the items is directly coupled to one and only one of the terminals of the other item, and/or that the items are indirectly coupled, in which case an electrical interaction different from direct coupling exists between the terminals of the items, for instance through one or more components.
  • a port In what follows, in line with circuit theory, a port has exactly two terminals.
  • An active antenna of the invention is an active antenna for radio reception in a known frequency band, the known frequency band having a least upper bound, the active antenna comprising: a first element, the first element being a transmission line having an outer conductor and an inner conductor, the transmission line having a first end and a second end, the outer conductor having a first end at the first end of the transmission line, the outer conductor having a second end at the second end of the transmission line, the inner conductor having a first end at the first end of the transmission line, the inner conductor having a second end at the second end of the transmission line, the first element being a part of a screened loop aerial; a second element, the second element being an electric conductor, the second element having a first end and a second end, the first end of the second element being coupled to the first end of the inner conductor, the second element being a part of the screened loop aerial; at least one single-port linear device, said at least one single -port linear device being coupled to the first end of the transmission line, an
  • At least one of the single-port linear devices is a resistor.
  • the one or more single-port linear devices present to the first end of the transmission line, at a frequency greater than said least upper bound, an impedance whose real part ranges from one-half to two times the real part of a characteristic impedance of the transmission line.
  • the active antenna may further comprise a passive linear filter having an input and an output, the input of the passive linear filter being coupled to the second end of the inner conductor, the input of the amplifier being coupled to the output of the passive linear filter, so that, in this case, the input of the amplifier is indirectly coupled to the second end of the inner conductor, through the passive linear filter.
  • a passive linear filter having an input and an output, the input of the passive linear filter being coupled to the second end of the inner conductor, the input of the amplifier being coupled to the output of the passive linear filter, so that, in this case, the input of the amplifier is indirectly coupled to the second end of the inner conductor, through the passive linear filter.
  • Figure 1 is a drawing of an active antenna of the prior art
  • Figure 2 is a plot of the absolute value of an impedance of the screened loop aerial of the active antenna shown in Fig. 1, as a function of frequency;
  • Figure 3 is a drawing of an active antenna of the invention (first embodiment);
  • Figure 4 is a drawing of a part of the active antenna shown in Figure 3 (first embodiment);
  • Figure 5 is a drawing of an active antenna of the invention (fourth embodiment);
  • Figure 6 is a second drawing of the active antenna shown in Figure 5 (fourth embodiment);
  • Figure 7 is a third drawing of the active antenna shown in Figure 5 (fourth embodiment).
  • Figure 8 is a plot of the absolute value of an impedance of a passive antenna which is a part of the active antenna shown in Fig. 5, as a function of frequency.
  • an active antenna of the invention for radio reception in a known frequency band, the known frequency band being the band 1 MHz to 300 MHz, the known frequency band having a least upper bound denoted by and equal to 300 MHz, the active antenna comprising: a first element (1), the first element being a transmission line having an outer conductor (11) and an inner conductor (12), the transmission line having a first end (101) and a second end, the outer conductor having a first end at the first end of the transmission line, the outer conductor having a second end at the second end of the transmission line, the inner conductor having a first end at the first end of the transmission line, the inner conductor having a second end at the second end of the transmission line; a second element (2), the second element being an electric conductor, the second element having a first end (201) and a second end, the first end of the second element being coupled to the first end of the inner
  • Figure 3 shows the whole active antenna. In Figure 3, the hidden edges and the hidden outlines are not shown.
  • the transmission line is a rectangular transmission line similar to the ones studied in the article of T.-S. Chen entitled “Determination of the Capacitance, Inductance and Characteristic Impedance of Rectangular Lines”, published in September 1960 in thcjournal IEEE Transactions on Microwave Theory and Techniques.
  • a cross-section of the rectangular transmission line comprises the inner conductor, which has a rectangular or circular cross-section, located inside the outer conductor, which has a rectangular and hollow cross- section.
  • the inner conductor is fixed in the outer conductor by utilizing insulating parts.
  • the characteristic impedance of this transmission line is close to 94 ohms at 100 MHz.
  • a cross-section of the second element is a rectangular and hollow electric conductor, similar to the outer conductor.
  • Figure 4 shows a part of the active antenna, in the vicinity of the first end of the transmission line and of the first end of the second element.
  • Figure 4 shows how the first terminal of the single-port linear device is directly coupled to the first end of the second element, and how the second terminal of the single-port linear device is directly coupled to the first end of the outer conductor (11).
  • Figure 4 shows a connection (14) through which the first end of the second element is coupled to the first end of the inner conductor.
  • Figure 4 shows that it is possible to consider that the first terminal of the single-port linear device is coupled to the first end of the inner conductor (12), through the connection (14).
  • the single -port linear device is coupled to the first end of the transmission line, in such a way that an impedance seen by the first end of the transmission line is affected by an impedance of the single-port linear device.
  • Figure 4 also shows an insulating part (13) used to support the inner conductor (12) in the outer conductor (11).
  • the specialist sees that the outer conductor, the base and the second element form a single- turn polygonal winding, the winding being used as a loop aerial.
  • the specialist also sees that the first element, the base and the second element form a screened loop aerial, which is a single-turn screened loop aerial similar to the one shown in Fig. 5 -22(a) of paragraph 5-4 of chapter 5 of said book of R.C. Johnson, and to the one shown in Fig. 9F of the report of G.A. Morgan, Jr. entitled “Analysis and calibration of loop probes for use in measuring interference fields”, published by the Naval Research Laboratory as NRL Report R-3486, in June 1949.
  • the first element is a part of the screened loop aerial
  • the second element is a part of the screened loop aerial
  • the base is a part of the screened loop aerial
  • this passive antenna comprises: the first element, the second element, the base and the single-port linear device.
  • the least upper bound corresponds to a wavelength in vacuum, equal to the velocity of light in vacuum divided by / MAX -
  • the base is hollow.
  • the amplifier is installed inside the base, and is power fed by a battery or a rechargeable battery.
  • the amplifier has an input impedance, denoted by Z j , an absolute value of the input impedance being less than 4 ohms, at any frequency in the known frequency band.
  • the amplifier is such that, if the output port is coupled to a suitable load, for instance a measuring receiver presenting an impedance close to 50 ohms, a voltage across the output port is equal to the product of an input current of the amplifier and a transimpedance, denoted by Z T , an absolute value of the transimpedance being substantially constant in the known frequency band.
  • the single-port linear device behaves substantially as a 94 ohms resistor.
  • the single-port linear device has, at a frequency greater than said least upper bound, a resistance and a reactance, the resistance being greater than an absolute value of the reactance.
  • the single-port linear device presents to the first end of the transmission line, at a frequency greater than said least upper bound, an impedance whose real part ranges from one-half to two times the real part of a characteristic impedance of the transmission line.
  • the first end of the transmission line sees, at any frequency, an impedance which results from its coupling to said polygonal winding and to the single-port linear device.
  • the specialist understands that it is possible to consider that the polygonal winding and the single-port linear device are connected in parallel. Second embodiment.
  • the second embodiment of a device of the invention also corresponds to the active antenna shown in Figures 3 and 4, and all explanations provided for the first embodiment are applicable to this second embodiment.
  • the input of the amplifier is directly coupled to the second end of the inner conductor, hence to the port of the passive antenna consisting of the screened loop aerial and the single-port linear device.
  • An impedance seen by the input of the amplifier is therefore an impedance of said passive antenna.
  • the active antenna comprises a screened loop aerial
  • the active antenna has an antenna factor which is substantially independent of the frequency in the known frequency band, and the active antenna is such that, at frequencies less than the least upper bound, a product of its antenna factor and the noise voltage density at the output of the active antenna is small. Consequently, the active antenna is a solution to the first problem described above in the section on prior art.
  • the active antenna comprises a passive linear filter having an input and an output; the input of the passive linear filter is coupled to the second end of the inner conductor, hence to the port of the passive antenna consisting of the screened loop aerial and the single-port linear device; and the input of the amplifier is coupled to the output of the passive linear filter.
  • An impedance seen by the input of the passive linear filter is therefore an impedance of said passive antenna.
  • the specialist understands that the characteristics of said passive antenna and of the amplifier interact in such a way that the single-port linear device increases the least upper bound of the frequency band over which the antenna factor of the active antenna is substantially independent of the frequency, and that it has been possible to obtain that the passive linear filter is a low-pass filter which effectively attenuates the frequencies greater than 2-5 / MAX > and which does not introduce unwanted variations of the antenna factor as a function of frequency, at the frequencies less than or equal to / A/ l v .
  • the active antenna comprises a screened loop aerial
  • the active antenna has an antenna factor which is substantially independent of the frequency in the known frequency band
  • the active antenna is not easily disturbed by a radio signal at a frequency greater than the least upper bound
  • the active antenna is such that, at frequencies less than the least upper bound, a product of its antenna factor and the noise voltage density at the output of the active antenna is small. Consequently, the active antenna is a solution to the first problem and to the second problem described above in the section on prior art.
  • an active antenna of the invention for radio reception in a known frequency band, the known frequency band being the band 9 kHz to 30 MHz, the known frequency band having a least upper bound denoted by / A/ l v and equal to 30 MHz
  • the active antenna comprising: a first element (1), the first element being a transmission line having an outer conductor (11) and an inner conductor (12), the transmission line having a first end and a second end, the outer conductor having a first end at the first end of the transmission line, the outer conductor having a second end at the second end of the transmission line, the inner conductor having a first end at the first end of the transmission line, the inner conductor having a second end at the second end of the transmission line, the first element being a part of a screened loop aerial; a second element (2), the second element being an electric conductor, the first element being a part of a screened loop aerial; a second element (2), the second element being an electric conductor, the first element being a part of a screened
  • Figure 5 is a front view of the active antenna.
  • the base comprises a fastening ring (5).
  • the fastening ring is used to fasten the active antenna to an antenna mast (9).
  • the base (3) is a box, the box containing the passive linear filter and the amplifier. This box may for instance be a metallic box. Thus, the base may provide a shielding of the passive linear filter and of the amplifier, that is to say an electromagnetic screening of the passive linear filter and of the amplifier.
  • Figure 6 is a front view of the active antenna without the lid of the base, and without the screws used to fasten the lid of the base to the base.
  • Figure 6 shows an electronic assembly (6) which comprises the passive linear filter and the amplifier.
  • Figure 7 is a back view of the active antenna, showing a coaxial connector (7) which materializes the output port, and a power supply connector (8) allowing to power feed the amplifier.
  • Said least upper bound corresponds to a wavelength in vacuum, equal to the velocity of light in vacuum divided by the least upper bound.
  • a sum of a length of the transmission line, measured from its first end to its second end, a length of the second element, measured from its first end to its second end, and a length, measured on the base, from the second end of the outer conductor to the second end of the second element, is less than a quarter of said wavelength in vacuum.
  • the screened loop aerial which is composed of the first element, the second element and the base, is consequently electrically small.
  • the transmission line is rigid.
  • the transmission line is a coaxial transmission line whose characteristic impedance is close to 75 ohms at 100 MHz.
  • the transmission line may for instance comprise a rigid or semi-rigid coaxial cable, suitably bent.
  • the transmission line may for instance comprise a flexible coaxial cable inserted in a rigid tube made of a dielectric material comprising a polymer, the rigid tube having a circular cross-section and being bent.
  • the transmission line may for instance comprise a flexible coaxial cable having a center conductor, a dielectric surrounding the center conductor, and a metallic braid surrounding the dielectric, the coaxial cable having no insulating jacket surrounding the metallic braid, the coaxial cable being inserted in a rigid metallic tube, the rigid metallic tube having a length, the rigid metallic tube having a circular cross-section and being bent, the metallic braid being in electric contact with the rigid metallic tube along the entire length of the rigid metallic tube, said inner conductor being the center conductor, said outer conductor being composed of the metallic braid in electric contact with the rigid metallic tube.
  • the second element may for instance comprise a rigid metallic bar, the rigid metallic bar having a circular cross-section, of the same diameter as the outer conductor, the rigid metallic bar being bent.
  • the second element may for instance comprise a rigid metallic tube, the rigid metallic tube having a circular cross-section, of the same diameter as the outer conductor, the rigid metallic tube being bent.
  • the second element may for instance be a conductor of a coaxial cable, for instance a shield of a semi-rigid coaxial cable.
  • the amplifier is a transimpedance amplifier or a transresistance amplifier, as defined above in the section on prior art.
  • the amplifier has an input impedance, an absolute value of the input impedance being very small at any frequency in the known frequency band, and the amplifier is such that, when the output port is coupled to a suitable load, a voltage across the output port is equal to the product of an input current of the amplifier and a transimpedance, an absolute value of the transimpedance being substantially constant in the known frequency band.
  • Each of the single-port linear devices is a 150 ohms resistor. From dc to each of the single-port linear devices behaves substantially as an ideal 150 ohms resistor. Consequently, each of the single -port linear devices has, at a frequency greater than said least upper bound, a resistance and a reactance, the resistance being greater than an absolute value of the reactance.
  • the specialist understands that two 150 ohms resistors connected in parallel as shown in Fig. 5 present a lower stray inductance than a single 75 ohms resistor of the same series.
  • the single-port linear devices present to the first end of the transmission line, at a frequency greater than said least upper bound, an impedance whose real part ranges from one-half to two times the real part of a characteristic impedance of the transmission line.
  • the screened loop aerial and the single-port linear devices form a passive antenna.
  • Simulations show that the characteristics of the screened loop aerial and of the single-port linear devices interact in such a way that, over a very broad frequency range, an absolute value of the ratio of the impedance of said passive antenna to an effective length of said passive antenna is substantially independent of the frequency; and in such a way that, from / Ai l v /3 to 5 , the impedance of said passive antenna has an absolute value which is approximately close to 75 ohms, and is approximately a resistance. More precisely, Figure 8 is a plot of the absolute value of the impedance of said passive antenna, as a function of frequency.
  • the specialist understands that the characteristics of said passive antenna and of the amplifier interact in such a way that the single port linear devices increase the least upper bound of the frequency band over which the antenna factor of the active antenna is substantially independent of the frequency, and that it has been possible to obtain that the passive linear filter is a low-pass filter which effectively attenuates the frequencies greater than 2 , and which does not introduce unwanted variations of the antenna factor as a function of frequency, at the frequencies less than or equal to / A/ I V .
  • the active antenna comprises a screened loop aerial
  • the active antenna has an antenna factor which is substantially independent of the frequency in the known frequency band
  • the active antenna is not easily disturbed by a radio signal at a frequency greater than the least upper bound
  • the active antenna is such that, at frequencies less than the least upper bound, a product of its antenna factor and the noise voltage density at the output of the active antenna is small.
  • the antenna factor is the ratio of the intensity of the electric field of an incident plane wave to the voltage developed by the active antenna across a specified impedance
  • the antenna factor is expressed in inverse of meter.
  • the specialist understands that the product of this antenna factor expressed in inverse of meter and a noise voltage density at the output of the active antenna expressed in r.m.s. volt per square root of hertz is a noise-equivalent electric field density, expressed in r.m.s. volt per meter per square root of hertz.
  • the active antenna has, at frequencies less than the least upper bound, a small noise-equivalent electric field density, expressed in r.m.s. volt per meter per square root of hertz.
  • the antenna factor is the ratio of the intensity of the magnetic field of an incident plane wave to the voltage developed by the active antenna across a specified impedance
  • the antenna factor is expressed in siemens per meter. Therefore, the active antenna has, at frequencies less than the least upper bound, a small noise-equivalent magnetic field density, expressed in r.m.s. ampere per meter per square root of hertz.
  • the specialist understands that the active antenna is a solution to the first problem and to the second problem described above in the section on prior art, and that the active antenna has ideal characteristics to perform accurate electromagnetic field measurements.
  • the output of the active antenna of the invention may for instance be connected to an end of a feeder (i.e., feed line), the feeder having another end which is coupled to a radio communication receiver, a measuring receiver, or a spectrum analyzer.
  • a feeder i.e., feed line
  • the active antenna of the invention is particularly suitable for electromagnetic field measurements, and for direction finding.
  • the active antenna of the invention may also comprise other devices, for instance a device which indicates when the level of the signals applied to the amplifier produces, or could produce, a non-linear behavior, leading for instance to saturation or overload at the output.

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  • Details Of Aerials (AREA)

Abstract

L'invention concerne une antenne active comprenant une antenne cadre blindée, par exemple une antenne pour des communications radio et/ou des mesures de champ électromagnétique. Une antenne active de l'invention comprend : un premier élément (1), le premier élément étant une ligne de transmission ayant un conducteur externe (11) et un conducteur interne (12), le premier élément étant une partie d'une antenne cadre blindée ; un second élément (2), le second élément étant un conducteur électrique, le second élément étant une partie de l'antenne cadre blindée ; une base (3) ; un dispositif linéaire à port unique (4) ayant, à une fréquence, une résistance et une réactance, la résistance étant supérieure à une valeur absolue de la réactance ; un filtre linéaire passif ; un amplificateur ayant une entrée et une sortie, l'entrée de l'amplificateur étant couplée à la sortie du filtre linéaire passif ; et un port de sortie, le port de sortie étant couplé à la sortie de l'amplificateur.
PCT/IB2021/051064 2020-02-28 2021-02-10 Antenne active comprenant une antenne cadre blindée WO2021171119A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR2002047A FR3107788B1 (fr) 2020-02-28 2020-02-28 Antenne active comportant un cadre blindé
FRFR2002047 2020-02-28

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Citations (6)

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Publication number Priority date Publication date Assignee Title
FR871799A (fr) * 1939-11-05 1942-05-09 Telefunken Gmbh Perfectionnements aux cadres radioélectriques
US2615134A (en) * 1946-01-09 1952-10-21 Rca Corp Antenna
FR2002047A1 (fr) 1968-02-16 1969-10-03 Standard Oil Co
US5352984A (en) 1992-11-04 1994-10-04 Cable Repair Systems Corporation Fault and splice finding system and method
WO2006097071A1 (fr) 2005-03-16 2006-09-21 Eads Deutschland Gmbh Systeme d'antenne de reception actif
US7750866B2 (en) * 2005-05-30 2010-07-06 Nxp B.V. Diversity antenna assembly for wireless communication equipment

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR871799A (fr) * 1939-11-05 1942-05-09 Telefunken Gmbh Perfectionnements aux cadres radioélectriques
US2615134A (en) * 1946-01-09 1952-10-21 Rca Corp Antenna
FR2002047A1 (fr) 1968-02-16 1969-10-03 Standard Oil Co
US5352984A (en) 1992-11-04 1994-10-04 Cable Repair Systems Corporation Fault and splice finding system and method
WO2006097071A1 (fr) 2005-03-16 2006-09-21 Eads Deutschland Gmbh Systeme d'antenne de reception actif
US7750866B2 (en) * 2005-05-30 2010-07-06 Nxp B.V. Diversity antenna assembly for wireless communication equipment

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