EP2728670A1 - Antenne pour signaux RF - Google Patents

Antenne pour signaux RF Download PDF

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Publication number
EP2728670A1
EP2728670A1 EP13190824.6A EP13190824A EP2728670A1 EP 2728670 A1 EP2728670 A1 EP 2728670A1 EP 13190824 A EP13190824 A EP 13190824A EP 2728670 A1 EP2728670 A1 EP 2728670A1
Authority
EP
European Patent Office
Prior art keywords
aerial
mhz
radiator element
band
stub
Prior art date
Legal status (The legal status 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 status listed.)
Ceased
Application number
EP13190824.6A
Other languages
German (de)
English (en)
Inventor
Alessandro Vittorio Botta
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Individual
Original Assignee
Individual
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Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP2728670A1 publication Critical patent/EP2728670A1/fr
Ceased legal-status Critical Current

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Classifications

    • 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
    • H01Q19/30—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 centre-fed and substantially straight, e.g. Yagi antenna

Definitions

  • the present invention relates to an aerial for radio frequency signals.
  • Aerials are known in the state of the art for radio frequency signals; said aerials generally consist of a radiator element adapted to generate the electromagnetic field (e.g. the radio frequency signal), a reflector and a plurality of director elements capable of modifying the electromagnetic field to make the aerial more directional and increase the gain.
  • Various aerials are present in the state of the art, which allow the reception and transmission of linearly polarized electromagnetic fields such as, for example, Yagi-Uda aerials comprising a supplied dipole (of the half-wave or folded type), a passive dipole which is longer than the supplied dipole, which serves as a reflector element, and a plurality of shorter passive director dipoles; the supplied dipole is arranged between the longer passive dipole and the plurality of shorter passive director dipoles and all the dipoles are aligned equi-oriented along an axis orthogonal to the dipoles.
  • Yagi-Uda aerials comprising a supplied dipole (of the half-wave or folded type), a passive dipole which is longer than the supplied dipole, which serves as a reflector element, and a plurality of shorter passive director dipoles; the supplied dipole is arranged between the longer passive dipole and the plurality of shorter passive director dipoles and all the dipoles are aligned equi-oriented along an
  • the field excited by the supplied dipole induces currents on the passive dipoles and said currents alter the radiation diagram with respect to the individual dipole; by opportunely designing the length and spacing of the individual elements, a directional aerial is obtained both on the horizontal plane and on the vertical plane with maximum radiation along the alignment axis.
  • Yagi-Uda aerials are highly used as receiving aerials for television type radio frequency signals.
  • Said aerials are designed to receive television signals in aVHF frequency band from 47 to 230 Mhz and a UHF frequency band from 470 MHz to 862 MHz; said aerials, called large band aerials, must have, a substantially constant gain for the entire band, a good linearity and directionality in said frequency bands.
  • the frequency band for television signals will be reduced to 790 MHz starting from 2013, so as to leave a band between 790 and 862 MHz for LTE standard mobile telephony.
  • a portion of the UHF band between 790 and 862 MHz will no longer be used for television signals but will be used for 4G-Long Term Evolution (LTE) mobile phone services.
  • the UHF band is restricted from 470-862 Mhz to 470-790 Mhz
  • filters on the market e.g. SAW filters
  • existing aerials for example filters to integrate with the balun of the aerials or to arrange on the cable of the aerial
  • filters on the aerial for example filters to integrate with the balun of the aerials or to arrange on the cable of the aerial
  • pass-band or band-elimination filters are adapted to filter and attenuate a radiofrequency signal; said filter are called pass-band or band-elimination filters.
  • the introduction of said filters on the aerial in addition to have a high cost, results in a degradation of the features of the aerials because it involves a great attenuation on the entire band.
  • the object of the present invention is to provide an aerial for radio frequency signals which meets the aforesaid European decision by maintaining unchanged the gain values on the bandwidth and the linearity features of the large band aerial.
  • said object is achieved by means of an aerial configured to receive and/or transmit radio frequency signals, said aerial comprising a reflector, at least one radiator element, a plurality of director elements and a rod element for supporting said reflector, said radiator element and said plurality of director elements, characterized by comprising at least two stubs mounted on the rod element and arranged between the reflector and the radiator element, said two stub being arranged in parallel to each other and one above the rod element and the other under the rod element.
  • Figures 1-6 show an aerial 1 for transmitting and receiving radio frequency signals, in particular linearly polarized radio signals in the UHF band, preferably an aerial configured to receive television signals, particularly linearly polarized radio signals in the UHF band.
  • Aerial 1 comprises a rod element 2 on which, going from end 21 to end 22 of the rod element, a reflector 3, a radiator element 4 and a plurality of director elements 5 are mounted opportunely spaced from each other and sized to optimize the aerial gain; as is known, director elements, together with reflector 3, give the aerial directivity towards the transmitting source of the signals, for example a television broadcaster.
  • the radiator element or radiator 4 (better shown in figures 9 and 11 ) is adapted to generate and/or receive linearly polarized radio signals and comprises an electrically supplied electroconductive element.
  • the radiator element 4 comprises a balun arranged in the housing 41 of element 4, which allows the impedance of the radiator element 4 to be matched to the one of the coaxial cable to which the aerial is connected by means of an opportune connector (not shown in the figures).
  • Reflector 2 and the director elements 5 are passive elements.
  • aerial 1 When transmitting, aerial 1 receives, by means of the balun, an alternating voltage which is transferred to the radiator element 4 where a time-variable charge distribution is achieved to create a linearly polarized electromagnetic field, i.e. the radio frequency signal to be transmitted.
  • the electromagnetic field received When receiving, the electromagnetic field received generates a time-variable charge distribution in the radiator element 4, e.g. a current, which is transferred to the coaxial cable by means of the balun.
  • a time-variable charge distribution in the radiator element 4 e.g. a current
  • Reflector 3 is preferably of dihedral type.
  • Reflector 3 comprises two metal grids 31 mounted on opposite sides of the rod element 2 by means of opportune fastening means 32 so as to form, with the horizontal plane, the opposite sides of a dihedral according to an opportune angle.
  • reflector 3, the radiator element 4 and the director elements 5 are aligned and equi-oriented along an axis orthogonal thereto, i.e. along the direction of maximum aerial gain.
  • the director elements 5 are preferably of the closed-loop type and are mounted so that the plane on which the loop rests is orthogonal to the direction of maximum aerial gain.
  • Each one of the director elements 5 comprises a support element 51 for the securing thereof on the rod element 2; the director elements 5 are mounted on the rod element 2 so that the respective geometrical centers are aligned along an axis which corresponds or is parallel to the direction of maximum aerial gain.
  • the number of the director elements 5, dimension thereof and the distance between them may be varied to improve aerial directivity and gain.
  • the aerial comprises at least one passive dipole, for example a stub 10 (better shown in figure 6 ), i.e. a cylindrical hollow or solid element but even an element with a different geometrical shape, preferably made of aluminium, mounted on the rod element 2 between reflector 3 and the radiator element 4.
  • a passive dipole for example a stub 10 (better shown in figure 6 ), i.e. a cylindrical hollow or solid element but even an element with a different geometrical shape, preferably made of aluminium, mounted on the rod element 2 between reflector 3 and the radiator element 4.
  • the dimensions of stub 10 are suitable for the wave length of the operational magnetic field, i.e. the magnetic field related to the radio frequency signals.
  • stub 10 between reflector 3 and the radiator element 4 allows acting as a band-limiting filter for the UHF frequency band for television signals from 470 MHz to 862 MHz, i.e. it is adapted to cut the aforesaid UHF frequency band so that the upper limit of the band is in a range between 790 and 830 MHz.
  • stub 10 is arranged adjacent to the radiator element 4 so as to cut the UHF frequency band at 790 MHz thus obtaining an aerial which meets the requirements of the aforesaid European decision.
  • stub 10 is a resonator which, when immersed in the magnetic field generated by the radiator element 4 in the position between reflector 3 and the radiator element 4, acts as an aerial frequency band limiter.
  • Stub 10 is a resonator normally tuned to a resonance frequency higher than the limit frequency of the aerial frequency band, i.e. if a band width is wanted from 470 MHz to 790 MHz, stub 10 is to resound at a frequency higher than 790 MHz, e.g. 830 MHz.
  • stub 10 i.e. its diameter and length, and the distance thereof from the radiator element 4 are selected in accordance with the portion of band to be eliminated.
  • the dimensions of the radiator element remaining unchanged, the length of the stub, the diameter thereof and the distance thereof from the radiator element affect the bandwidth of the aerial; in particular, by increasing the length or the diameter of the stub, the frequency bandwidth of the aerial is decreased.
  • the greater the length of stub 10 the smaller the band width of the aerial, i.e. the length of the stub is inversely proportional to the bandwidth of the aerial, while when the length of stub 10 is equal, the greater the diameter thereof and the smaller the bandwidth of the aerial.
  • the distance of stub 10 from the radiator element affects the falling edge of the aerial gain; the smaller said distance, the steeper the falling edge of the aerial gain at the desired frequency, e.g. 790 MHz.
  • Stub 10 is a passive metal element, i.e. it is not supplied. Stub 10 may be mounted on the rod element 2, above or under the rod element 2; stub 10, the radiator element 4 and the director elements 5 are aligned along an axis orthogonal thereto.
  • the aerial comprises another stub 11 arranged again between reflector 3 and the radiator element 4 and in parallel to the stub 10; the two stubs 10, 11 are arranged one under and one above the rod element 2 with the rod element 2 again interposed between the two stubs 10, 11.
  • Stub 11 is smaller than stub 10 and, when combined with stub 10, allows a more effective band-elimination filter to be obtained, in particular of the UHF band for television signals.
  • Stub 11 acts in particular at the frequencies over 800 MHz.
  • the combination of stub 10 with stub 11 arranged in parallel one above and the other under the rod element 2 allows a band-elimination filter to be obtained which is adapted to eliminate the frequency band from 790 MHz to a frequency ranging between 860 MHz and 900 MHz.
  • a band attenuation ranging between 10 and 14 dbmV; there is a steep decrease of the gain at 790 MHz, while there is a steep increase of the gain at the frequency ranging between 862-900 MHz.
  • a band-elimination filter which is adapted to eliminate the frequency band from 790 MHz to 900 MHz.
  • the upper frequency of the band-elimination filter has been chose at 900 MHz and not at 862 MHz for minimizing the interferences with the LTE transmissions at the adjacent frequencies.
  • the distance between the two stubs 10, 11 is a few centimeters, for example 2.45 cm.
  • the diameter of the stubs 10, 11 is 6 mm and the distance from the center of the radiator element 4 is 30 mm.
  • the combination of the stubs 10 and 11, which are arranged in parallel one above and the other under the rod element 2, allows the features of a large band aerial, as the band linearity, to be unchanged in the frequency band from 470 MHz to 790 MHz.
  • Figure 7 shows an aerial in accordance with a variant of the embodiment of the present invention
  • the aerial in figure 7 comprises all the elements of the aerial in figures 1-5 , and also a further stub 12, arranged between the radiator element 4 and the first director element 5 of the plurality of director elements and mounted again on the rod element 2 so as to be aligned with the director elements 5.
  • Stub 12 does not affect the directivity of the aerial, rather the stability of the aerial gain because stub 12 acts as impedance matching between the director elements 5 and the radiator element 4.
  • Stub 12 allows making the aerial gain more stable in the band going from 470 MHz to 790 MHz.

Landscapes

  • Aerials With Secondary Devices (AREA)
  • Input Circuits Of Receivers And Coupling Of Receivers And Audio Equipment (AREA)
  • Burglar Alarm Systems (AREA)
EP13190824.6A 2012-10-31 2013-10-30 Antenne pour signaux RF Ceased EP2728670A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IT001872A ITMI20121872A1 (it) 2012-10-31 2012-10-31 Antenna per segnali in radiofrequenza.

Publications (1)

Publication Number Publication Date
EP2728670A1 true EP2728670A1 (fr) 2014-05-07

Family

ID=47471914

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13190824.6A Ceased EP2728670A1 (fr) 2012-10-31 2013-10-30 Antenne pour signaux RF

Country Status (2)

Country Link
EP (1) EP2728670A1 (fr)
IT (1) ITMI20121872A1 (fr)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105226397A (zh) * 2014-07-03 2016-01-06 智勤科技股份有限公司 具有高隔离度的天线装置
IT201800010806A1 (it) * 2018-12-17 2020-06-17 Marco Mastrantonio Antenna m

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897497A (en) * 1959-03-13 1959-07-28 Jr Lewis H Finneburgh Selective multiple channel tv antennas
FR1321567A (fr) * 1962-02-08 1963-03-22 Perfectionnement aux antennes réceptrices pour très hautes fréquences, notamment pour télévision
GB940353A (en) * 1960-12-05 1963-10-30 Hans Kolbe Improvements in or relating to directional antennae
DE1298161B (de) * 1964-04-24 1969-06-26 Siemens Ag Yagi-Antenne fuer nur einen Frequenzbereich
EP2639882A1 (fr) * 2012-03-15 2013-09-18 Angel Iglesias, S.A. Dispositif de réception de signaux radio à filtrage de fréquence

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2897497A (en) * 1959-03-13 1959-07-28 Jr Lewis H Finneburgh Selective multiple channel tv antennas
GB940353A (en) * 1960-12-05 1963-10-30 Hans Kolbe Improvements in or relating to directional antennae
FR1321567A (fr) * 1962-02-08 1963-03-22 Perfectionnement aux antennes réceptrices pour très hautes fréquences, notamment pour télévision
DE1298161B (de) * 1964-04-24 1969-06-26 Siemens Ag Yagi-Antenne fuer nur einen Frequenzbereich
EP2639882A1 (fr) * 2012-03-15 2013-09-18 Angel Iglesias, S.A. Dispositif de réception de signaux radio à filtrage de fréquence

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
EUROPEAN UNION, OFFICIAL JOURNAL OF THE EUROPEAN UNION, May 2010 (2010-05-01)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105226397A (zh) * 2014-07-03 2016-01-06 智勤科技股份有限公司 具有高隔离度的天线装置
TWI549361B (zh) * 2014-07-03 2016-09-11 智勤科技股份有限公司 具有高隔離度的天線裝置
CN105226397B (zh) * 2014-07-03 2018-01-23 智勤科技股份有限公司 具有高隔离度的天线装置
IT201800010806A1 (it) * 2018-12-17 2020-06-17 Marco Mastrantonio Antenna m

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Publication number Publication date
ITMI20121872A1 (it) 2014-05-01

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