EP0350364A1 - Wideband receiving antenna - Google Patents

Wideband receiving antenna Download PDF

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Publication number
EP0350364A1
EP0350364A1 EP89401791A EP89401791A EP0350364A1 EP 0350364 A1 EP0350364 A1 EP 0350364A1 EP 89401791 A EP89401791 A EP 89401791A EP 89401791 A EP89401791 A EP 89401791A EP 0350364 A1 EP0350364 A1 EP 0350364A1
Authority
EP
European Patent Office
Prior art keywords
aerial
antenna
cone
characterized
height
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.)
Granted
Application number
EP89401791A
Other languages
German (de)
French (fr)
Other versions
EP0350364B1 (en
Inventor
Claude Boulesteix
Maurice Elkael
Joel Jeannolle
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Thales SA
Original Assignee
Thomson CSF SA
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
Priority to FR8809309A priority Critical patent/FR2634068B1/en
Priority to FR8809309 priority
Application filed by Thomson CSF SA filed Critical Thomson CSF SA
Publication of EP0350364A1 publication Critical patent/EP0350364A1/en
Application granted granted Critical
Publication of EP0350364B1 publication Critical patent/EP0350364B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q9/00Electrically-short antennas having dimensions not more than twice the operating wavelength and consisting of conductive active radiating elements
    • H01Q9/04Resonant antennas
    • H01Q9/30Resonant antennas with feed to end of elongated active element, e.g. unipole
    • H01Q9/40Element having extended radiating surface
    • HELECTRICITY
    • H01BASIC ELECTRIC ELEMENTS
    • H01QANTENNAS, i.e. RADIO AERIALS
    • H01Q5/00Arrangements for simultaneous operation of antennas on two or more different wavebands, e.g. dual-band or multi-band arrangements
    • H01Q5/50Feeding or matching arrangements for broad-band or multi-band operation

Abstract

The invention relates to an antenna intended for the reception of waves in the myriametric to decametric and even metric bands. The antenna comprises an aerial (A) of the inverted cone type, placed in elevation with respect to the ground and coupled to the receivers (R, R ') to be supplied by as many channels made of passive elements as of receivers; each channel has its filter cell (L1-C1, L2-C2), its impedance matching circuit (T1, T2) for coupling to the receiver (R, R ') and possibly a resistor (R1, R2) serving in particular to adjust, at an optimal reception level, the signal supplied to the receiver. Application to broadband reception antennas.

Description

  • The present invention relates to a broadband antenna, intended for reception on wavelengths ranging from the myriametric range (corresponding to the VLF band of Anglo-Saxon literature) to the decametric range (corresponding to the HF band of the Anglo-Saxon literature) and even metric (corresponding to the VHF band of Anglo-Saxon literature).
  • There are reception antennas operating from myriametric waves to HF waves. However, these antennas are active antennas, that is to say that they comprise active, non-linear components, such as transistors. These active antennas have various drawbacks:
    - they require power,
    - because of their relatively large effective height, they are very sensitive to jammers constituted, for example, by a neighboring transmitting antenna,
    - they have significant non-linearities due to the active components used for impedance matching and, moreover, these active components generate significant noise,
    - they are very sensitive to disturbances due to electromagnetic pulses of high amplitude.
  • The object of the present invention is to avoid or, at the very least, to reduce these drawbacks.
  • This is obtained by the association of an aerial specially designed to present a wide band of frequencies of use, and of channels studied to achieve an optimal coupling between the aerial and the receivers to be connected to this aerial.
  • According to the present invention, a broadband reception antenna is proposed, characterized by the combination of an aerial of inverted cone type, of a conductive support for placing the top of the cone in elevation relative to the ground. of a height of the order of magnitude of the height of the cone and of a passive adaptation circuit comprising n channels (n: positive integer) relating respectively to n reception frequency bands, each channel being coupled to the aerial and comprising, in series, a filtering cell to isolate its reception frequency band and a broadband impedance matching transformer.
  • The present invention will be better understood and other characteristics will appear with the aid of the description below and of the figures relating thereto which represent:
    • - Figure 1, a perspective view of an antenna according to the invention
    • FIG. 2, a partial view, in section, of the antenna according to FIG. 1,
    • - Figure 3, the electrical diagram of the antenna according to Figure 1.
  • In the various figures, the corresponding elements have been designated by the same references.
  • FIG. 1 shows an antenna according to the invention, the aerial of which, A, comprises an inverted cone, B, surmounted by a roof sheet, T; the cone rests on a foot P.
  • The inverted cone, B, of the aerial is produced by means of eight metal rods B1 to B8 regularly arranged according to generatrices of the cone; the cone makes an angle of 33 degrees and the rods which constitute it have a length of 1.50 meters. The choice of an aerial of the inverted cone type is due to the fact that the "thick" structure of such an aerial ensures a wide operating band.
  • The roof sheet, T, is formed by eight metal rods of one meter, arranged in a star and fixed by rivets on the upper ends of the rods B1 to B8. The presence of this roof sheet makes it possible to greatly increase the internal capacity of the aerial.
  • The rigidity of the cone and of the roof ply is reinforced by a vertical metal rod, D, arranged along the axis, not shown, of the cone; this rod D is fixed, at its upper end, to the center of the star formed by the roof ply; the fixing, at their lower end, of the rods of the inverted cone B and of the rod D will be specified with the aid of FIG. 2. It should be noted that the rod D being entirely disposed inside the cone, does not participate not radio activity from the air.
  • The foot P comprises a vertical metal cylinder P1, 1.20 meters high and 18 centimeters in diameter surmounted by a cover, P2, whose role is to ensure the mechanical connection between the cylinder and the aerial while electrically insulating from each other; the constitution of the cover P2 will be specified with the aid of FIG. 2. The cylinder P1, the height of which is of the order of magnitude that of the cone B, is fixed to the ground by means of a metal base, P3, formed of a horizontal plate and four vertical brackets welded to the lower end of the cylinder P1. The use of a foot, such as the P foot, to raise the aerial above the ground, was determined by the desire to increase the effective height of the antenna, i.e. the ratio between the voltage available at the antenna feed point and the incident field in the vicinity of the antenna.
  • FIG. 2 is a partial view, in a vertical sectional plane passing through the rod D, of the foot P and of the bottom of the aerial A of the antenna according to FIG. 1. For ease of representation, a cutout, indicated by two lines broken in axis lines, allowed to reduce in the drawing the length of the foot by removing the central part which is identical to the top of the bottom part and the bottom of the top part of the foot.
  • Figure 2 shows the metal plate of the base P3 which is welded to the lower end of the cylinder P1 and which rests on the ground. A mounting assembly, not shown, is associated with the base, it is made of threaded rods which pass vertically through the plate of the base P3, of bolts aimed on the threaded rods and coming to bear on the plate, and of blocks of concrete poured into the ground and in which are taken the lower ends of the threaded rods.
  • FIG. 2 also shows the constitution of the upper part of the foot P, with the cover P2 crossed by the rods of the aerial A and by a spark gap Y, with a printed circuit G whose electrical diagram is shown in FIG. 3 and with connections between the aerial, the printed circuit, the cylinder P1 and two coaxial antenna output plugs, S1-S2, S3-S4, which pass through the wall of the lower part of the cylinder P1. The cover P2 includes a horizontal metal plate J which covers an insulating plate K placed on a collar secured to the upper end of the cylinder P1; the fixing of the plate K on the flange on the one hand and of the plate J on the plate K on the other hand is ensured by means of screws not shown. The spark gap Y, the housing of which is insulating, is closed by a cap accessible above the plate J; spark gap Y is in electrical contact, through one of its terminals, with plate J and, through the other of its terminals, with cylinder P1 to which it is connected by means of a metal support welded to the internal wall of the cylinder P1. The printed circuit G, which is arranged in the cylinder P1 in the immediate vicinity of the cover, is an adaptation circuit intended to allow coupling between the aerial A and receivers to be connected to the sockets S1-S2 and S3-S4; the adaptation circuit carried by the printed circuit is in electrical contact on the one hand at a point N with the tip of the cone of the air thanks to a connection H which is none other than the extension of the rod D below the cover P2 and on the other hand, over the entire periphery M of the printed circuit, with the internal wall of the metal cylinder P1; two cables Q1, Q2 provide the connections between the printed circuit G and the sockets S1-S2, S3-S4. It should be noted that the rods such as B1, B5 and D pass through the metal plate J through holes to the walls of which they are welded so as to give good rigidity to the aerial and to ensure a strictly identical potential at the lower ends of all the stems.
  • Figure 3 is an electrical diagram of the antenna according to Figures 1 and 2 with, in addition, two resistors R and R 'connected respectively to the sockets S1-S2 and S3-S4; these two resistors include the receivers intended to be connected to the antenna. FIG. 3 represents the aerial A of FIGS. 1 and 2 with its terminals N and M corresponding respectively to the hot spot and to the ground of the antenna.
  • Between terminals M and N is connected the spark gap Y, which has a parasitic capacity of 5 pF. This spark gap is designed to short-circuit, and thus preserve the components mounted downstream of it, when it detects an "electromagnetic attack" picked up by the aerial A. This detection occurs when the voltage across the terminals of the spark gap exceeds the spark gap threshold voltage; there is then ionization of the gas contained in the spark gap tube which produces an electric arc between the terminals of the spark gap and this arc which forms a short circuit persists the time that the disturbance lasts.
  • Between the terminals M and N are also connected two channels which lead respectively to resistors R and R ′ appearing receivers.
  • The first channel, which will be called the high channel, is designed to lead to a receiver working in the 2-30 mHz band. It comprises, in series from terminal N to terminal M, a resistor R1 of 330 ohms, a capacitor C1 of 220 pF and an inductance L1 of 100 microhenrys; an impedance matching transformer, T1, with a 4/1 ratio to its primary, one terminal of which is grounded, connected in parallel to the inductor L1 and its secondary, one terminal of which is to ground, connected to resistance R; a capacitor C ′ drawn in dashed lines represents the parasitic capacitance, of the order of 10 pF, which exists at the primary of the transformer T1.
  • The second channel, which will be called the low channel, is designed to lead to a receiver working in the band 20-100 kHz. It comprises, in series from terminal N to terminal M, a resistor R2 of 10 kilo-ohms and an inductance L2 of 0.7 Henry. A capacitor C2 of 100 pF is mounted in parallel on the inductor L2 as well as the primary of an adaptation transformer of impedance, T2, of ratio 25/1; the secondary of the transformer T2, one of the two output terminals of which is grounded, is connected to the resistor R2.
  • In the assembly according to FIG. 3 the resistors R1 and R2 have several functions:
    - adjust the level of the signal supplied to the receiver connected to the channel, so that this receiver operates at the optimum received signal level, that is to say with a level sufficient to allow listening but no more, so as to don't have too much noise,
    - serve to protect the track against residual parasitic voltage not stopped by the spark gap during, for example, a lightning strike.
  • It should be noted that the resistors R1 and R2 are actually constituted by two sets of resistors, the total values of which are those indicated above, and that mobile short-circuits make it possible to short-circuit all or part of the resistors R1 and R2 so as to optimize reception depending on the site where the antenna is located.
  • The filter cell constituted by the capacitor C1 and the inductor L1 is intended to isolate the high channel from the low channel by ensuring high-pass filtering, while the filter cell L2-C2 isolates the low channel from the high channel by forming a plug circuit substantially centered on 20 kHz. It should be noted that, in the assembly according to FIG. 3, the values indicated for L1, L2 and C2 respectively take into account the parasitic inductances at the terminals of the primary of the transformers T1 and T2 and the parasitic capacitance at the terminals of the primary of the transformer T2.
  • The antenna which has just been described presents an omnidirectional radiation pattern in azimuth for a polarization. vertical electric field and a single lobe diagram, with a zero on the vertical axis, for vertical polarization of the electric field. As regards the effective height of the antenna, that is to say the V / E ratio between the voltages supplied at the terminals of the receivers and the module of the incident field in the vicinity of the antenna, the following results have been obtained:
    -effective height in the band 20 to 100 kHz:
    -40 to -35 dB.m
    - effective height in the band 2 to 30 MHz:
    -13 to -8 dBm
    these values, which are compatible with the noise levels of galactic, atmospheric and industrial origin received by the air, ensure good reception sensitivity while minimizing the influence of any interferers existing in the vicinity of the air.
  • In addition, it should be noted that the antenna, which has just been described, can be used with a receiver working at the bottom of the metric band subject to an adaptation of the high channel for such use; it should also be noted that this antenna has good protection against electromagnetic attack and, due to the passive nature of its components as long as the spark gap Y is not triggered, has a high level of operating linearity.
  • The present invention is not limited to the example described, thus the number of channels can be reduced to 1 or be greater than 2; each channel is determined according to the receiver for which it is intended and the isolation to be achieved in relation to the other channels. Similarly, the antenna may not include a spark gap or use, in its channels, filter cells and adaptation circuits of impedance different from those described with the aid of FIG. 3.

Claims (4)

1. Broadband reception antenna, characterized by the combination of an aerial (A) of inverted cone type (B), of a conductive support (P) to place the top (N) of the cone in elevation with respect to the ground (S) of a height of the order of magnitude of the height of the cone and of a passive adaptation circuit comprising n channels (n: positive integer) relating respectively to n reception frequency bands, each channel being coupled to the aerial and comprising, in series, a filtering cell (C1-L1, C2-L2) to isolate its reception frequency band and a broadband impedance matching transformer (T1, T2) .
2. Antenna according to claim 1, characterized in that at least one of the n channels comprises in series an attenuating element (R1, R2).
3. Antenna according to one of the preceding claims, characterized in that it comprises a spark gap (Y) coupled to the aerial to constitute protection against lightning.
4. Antenna according to one of the preceding claims, characterized in that the aerial (A) comprises a roof (T) constituted by a planar element disposed at the base of the inverted cone (B) of the aerial to increase the height effective and equivalent capacity of the air.
EP89401791A 1988-07-08 1989-06-23 Wideband receiving antenna Expired - Lifetime EP0350364B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
FR8809309A FR2634068B1 (en) 1988-07-08 1988-07-08 Broadband receiving antenna
FR8809309 1988-07-08

Publications (2)

Publication Number Publication Date
EP0350364A1 true EP0350364A1 (en) 1990-01-10
EP0350364B1 EP0350364B1 (en) 1995-01-11

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Family Applications (1)

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EP89401791A Expired - Lifetime EP0350364B1 (en) 1988-07-08 1989-06-23 Wideband receiving antenna

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EP (1) EP0350364B1 (en)
DE (1) DE68920494T2 (en)
FR (1) FR2634068B1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2500056C1 (en) * 2012-05-11 2013-11-27 Открытое акционерное общество "Омский научно-исследовательский институт приборостроения" (ОАО "ОНИИП") Helical hf antenna
EP2784874A3 (en) * 2013-03-24 2014-12-03 Delphi Deutschland GmbH Broadband monopole antenna for vehicles for two frequency bands separated by a frequency gap in the decimeter wavelength

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB529152A (en) * 1938-05-24 1940-11-14 Telefunken Gmbh Improvements in or relating to radio aerial arrangements
GB598548A (en) * 1944-12-01 1948-02-20 William Joseph O Brien Improvements in or relating to antennae for radio transmitters
US2954559A (en) * 1959-03-24 1960-09-27 Allen A Yurek Prefabricated sleeve antenna
US3273067A (en) * 1963-03-28 1966-09-13 Whittaker Corp Hybrid ring multicoupler for a plurality of pairs of transmitters
US3701159A (en) * 1970-12-18 1972-10-24 Nat Defence Canada Discone antenna
US4095229A (en) * 1977-02-22 1978-06-13 General Motors Corporation Triband vehicle antenna
FR2591039A1 (en) * 1985-12-04 1987-06-05 Thomson Csf Wide bandwidth discone antenna

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB529152A (en) * 1938-05-24 1940-11-14 Telefunken Gmbh Improvements in or relating to radio aerial arrangements
GB598548A (en) * 1944-12-01 1948-02-20 William Joseph O Brien Improvements in or relating to antennae for radio transmitters
US2954559A (en) * 1959-03-24 1960-09-27 Allen A Yurek Prefabricated sleeve antenna
US3273067A (en) * 1963-03-28 1966-09-13 Whittaker Corp Hybrid ring multicoupler for a plurality of pairs of transmitters
US3701159A (en) * 1970-12-18 1972-10-24 Nat Defence Canada Discone antenna
US4095229A (en) * 1977-02-22 1978-06-13 General Motors Corporation Triband vehicle antenna
FR2591039A1 (en) * 1985-12-04 1987-06-05 Thomson Csf Wide bandwidth discone antenna

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2500056C1 (en) * 2012-05-11 2013-11-27 Открытое акционерное общество "Омский научно-исследовательский институт приборостроения" (ОАО "ОНИИП") Helical hf antenna
EP2784874A3 (en) * 2013-03-24 2014-12-03 Delphi Deutschland GmbH Broadband monopole antenna for vehicles for two frequency bands separated by a frequency gap in the decimeter wavelength

Also Published As

Publication number Publication date
FR2634068A1 (en) 1990-01-12
DE68920494T2 (en) 1995-05-18
EP0350364B1 (en) 1995-01-11
FR2634068B1 (en) 1990-09-14
DE68920494D1 (en) 1995-02-23

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