EP0814537B1 - Procédé et dispositif de réduction des champs arrières et abaissés sous l'horizon dans un groupe d'antennes - Google Patents
Procédé et dispositif de réduction des champs arrières et abaissés sous l'horizon dans un groupe d'antennes Download PDFInfo
- Publication number
- EP0814537B1 EP0814537B1 EP19970401351 EP97401351A EP0814537B1 EP 0814537 B1 EP0814537 B1 EP 0814537B1 EP 19970401351 EP19970401351 EP 19970401351 EP 97401351 A EP97401351 A EP 97401351A EP 0814537 B1 EP0814537 B1 EP 0814537B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- antennae
- field
- elementary
- antennas
- group
- 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.)
- Expired - Lifetime
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q3/00—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system
- H01Q3/26—Arrangements for changing or varying the orientation or the shape of the directional pattern of the waves radiated from an antenna or antenna system varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01Q—ANTENNAS, i.e. RADIO AERIALS
- H01Q21/00—Antenna arrays or systems
- H01Q21/29—Combinations of different interacting antenna units for giving a desired directional characteristic
Definitions
- the invention relates to a method and a device for decrease the rear radiation of an antenna while lowering this weakened radiation to a selected area below the horizon. She applies more particularly to aerials made up of at least two elementary antennas including the phases are opposite in pairs on the back of said air.
- Such a system mainly allows a diffusion linear or not of a plurality of transmitters operating on the same frequency, synchronized or no. This is particularly the case of a chain of transmitters isofrequencies along a highway, the weak radiation of the antennas on their rear reducing considerably the length of the interference zone with the previous transmitter.
- the system allows to reduce to a few hundred meters the interference zone between relays.
- the effect backward radiation cancellation of the antenna array is disturbed.
- the upper antenna being located at 34 m, and the antenna less than 2 m below, there is a difference of a few dB between the two radiations in the area interference. It is therefore necessary to compensate for these side effects so that a minimum of energy reaches the interference zone.
- the object of the invention is therefore to reduce the rear radiation of an array of antennas emission while lowering this attenuation towards a selected area under the horizon.
- the vertical interval between the elementary antennas of a couple is related to the wavelength and the intrinsic structure of the antenna. According to a particular form of the invention, this interval is about 2 m.
- the device for implementing the invention is characterized in that it includes a distributor of variable power to adjust the amplitude of the field radiated by each of the elementary antennas of so as to obtain identical result fields in a specific area behind the group of antennas and a phase correction device on each of the elementary antennas in order to obtain an opposition of perfect phase.
- the power distributor consists of a volume conductor of length ⁇ / 4, of a fixed line and of two moving lines moving relative to the previous in order to increase the level of the low antenna and reduce that of the high antenna.
- the lines are supplied by serial lines open to their ends (intangible short circuit between the beginning of the serial line and that of the mobile line).
- the phase correction device is consisting of an adjustable line
- the antennas elementary 1 and 2 of the aerial radiation system 3 radio transmitter are arranged one above the other and shifted horizontally.
- the height H1 of the upper antenna 2 is 34 m. and the antenna lower 1 is located below at an interval ⁇ H about 2 m.
- the receiving antenna 4 of a vehicle traveling on the highway culminates at a height H2 about 2 m.
- Each antenna radiates a V field. makes the horizontal shift of ⁇ / 4 of the antennas the field V1 of antenna 1 and field V2 of antenna 2 are added forward, so that we have forward from the transmitter a resulting field equal to V1 + V2, and retreat backwards, so that the field resulting back from the transmitter is V2 - V1.
- the radiation is reflected on the floor.
- the receiving antenna also captures the resulting reflected field and this disrupts reception.
- the receiving antenna 4 receives from the transmitting antenna 1 a direct field V1 (X1, Y1) and a reflected field VR1 (X2, Y2); from antenna 2 a direct field V2 (X3, Y3) and a reflected field VR2 (X4, Y4).
- Y1 and Y3 are neighbors of 0.
- the object of the invention is to lower the value of R.
- the device according to the invention is shown in the figure 3.
- the signal from the transmitter 5 is transmitted to the dispatcher variable power 6 which adjusts the amplitude of signals to elementary antennas to compensate the difference in levels received by the receiver since each of the antennas due to their difference altitude so as to obtain a minimum field R in a area given behind the antennas.
- this power distributor consists of a cylinder comprising a central line coupled to two lines to variable coupling by rotation.
- the mobile lines are excited by an open serial line connection for make a non-contact rotating joint.
- the rotation two lines with variable coupling around the line central allows to distribute the power
- Each of the adjusted outputs of the distributor is connected to an adjustable phase correction line 7 for the antenna signal 1 and 8 for the antenna signal 2.
- this area is the interference zone between the rear radiation of the transmitter and the front radiation of the transmitter previous in a linear broadcasting chain simulcast.
Landscapes
- Variable-Direction Aerials And Aerial Arrays (AREA)
Description
- on sélectionne l'endroit où le champ résultant doit être minimal en ajustant les phases de chacune des antennes élémentaires de telle façon que la valeur minimale du champ soit obtenue dans une zone déterminée à l'arrière du groupe d'antennes et vue de celui-ci sous un angle déterminé. Les antennes étant situées à des hauteurs différentes, les niveaux reçus sur la route de chacune d'entre elles sont différents. Ce phénomène est dû à ce que les zones de réflexion n'étant pas situées au même endroit, la sommation du trajet direct et du trajet réfléchi pour chaque antenne donne une valeur différente. On égalise les amplitudes des antennes élémentaires en répartissant la puissance de façon que le champ reçu résultant soit minimal dans la zone choisie.
Claims (5)
- Procédé de réduction des champs arrière d'un groupe d'antennes directionnelles comportant au moins un couple d'antennes élémentaires décalées entre elles verticalement d'un certain intervalle et horizontalement de λ/4, caractérisé en ce que :on sélectionne l'endroit où le champ résultant doit être minimal en ajustant les phases de chacune des antennes élémentaires de telle façon que la valeur du champ soit réduite dans une zone déterminée à l'arrière du groupe d'antennes et vue de celui-ci sous un angle déterminé sous l'horizon,on égalise les amplitudes des signaux reçus des antennes élémentaires en répartissant la puissance de façon que le champ rayonnés résultant soit minimal dans la zone choisie.
- Dispositif de rayonnement d'une émission radioélectrique, comportant un système aérien d'antennes constitué d'au moins un couple d'antennes élémentaires décalées verticalement d'une certaine hauteur et horizontalement de λ/4, caractérisé en ce qu'il comporte en outre un répartiteur de puissance variable permettant d'ajuster l'amplitude des champs reçus de chacune des antennes élémentaires et un dispositif de correction de phase sur chacune des antennes élémentaires, de manière à obtenir un champ résultant nul dans une zone déterminée à l'arrière du groupe d'antennes et vue de celui-ci sous un angle déterminé sous l'horizon.
- Dispositif selon la revendication 2, caractérisé en ce que le répartiteur de puissance est constitué par un volume conducteur de longueur égale à λ/4, d'une ligne fixe et de deux lignes mobiles, excitées par une connexion ligne ouverte, se déplaçant par rapport à la précédente de manière à augmenter le niveau de l'antenne basse et à réduire celui de l'antenne haute.
- Dispositif selon la revendication 2, caractérisé en ce que le dispositif de correction de phase est constitué d'une ligne ajustable.
- Application du procédé selon la revendication 1 à une chaíne d'émetteurs isofréquences le long d'une voie de circulation.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR9607603A FR2750257B1 (fr) | 1996-06-19 | 1996-06-19 | Procede et dispositif de rayonnement a fort rapport avant/arriere dirige |
| FR9607603 | 1996-06-19 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0814537A1 EP0814537A1 (fr) | 1997-12-29 |
| EP0814537B1 true EP0814537B1 (fr) | 2004-11-17 |
Family
ID=9493195
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP19970401351 Expired - Lifetime EP0814537B1 (fr) | 1996-06-19 | 1997-06-16 | Procédé et dispositif de réduction des champs arrières et abaissés sous l'horizon dans un groupe d'antennes |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0814537B1 (fr) |
| DE (1) | DE69731582D1 (fr) |
| FR (1) | FR2750257B1 (fr) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4196436A (en) * | 1978-11-14 | 1980-04-01 | Ford Motor Company | Differential backlobe antenna array |
| US5107273A (en) * | 1981-05-11 | 1992-04-21 | The United States Of America As Represented By The Secretary Of The Army | Adaptive steerable null antenna processor with null indicator |
| US4423392A (en) * | 1981-11-30 | 1983-12-27 | Wolfson Ronald I | Dual-mode stripline antenna feed performing multiple angularly separated beams in space |
| FR2639492B1 (fr) * | 1988-11-23 | 1994-07-29 | Autoroutes Cie Financ Indle | Procede et dispositif de radiodiffusion isofrequence a interferences attenuees |
-
1996
- 1996-06-19 FR FR9607603A patent/FR2750257B1/fr not_active Expired - Fee Related
-
1997
- 1997-06-16 DE DE69731582T patent/DE69731582D1/de not_active Expired - Lifetime
- 1997-06-16 EP EP19970401351 patent/EP0814537B1/fr not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| DE69731582D1 (de) | 2004-12-23 |
| FR2750257A1 (fr) | 1997-12-26 |
| FR2750257B1 (fr) | 1998-08-21 |
| EP0814537A1 (fr) | 1997-12-29 |
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