Telecommunications – Carrier wave repeater or relay system – Directive antenna
Reexamination Certificate
1998-07-31
2001-01-30
To, Doris H. (Department: 2745)
Telecommunications
Carrier wave repeater or relay system
Directive antenna
C455S011100, C455S562100, C342S368000, C342S370000, C342S373000, C343S824000, C343S844000, C343S893000
Reexamination Certificate
active
06181914
ABSTRACT:
The present invention relates to systems for transmitting radio signals, and more particularly in such systems, to repeaters which are used for receiving radio signals from a transmitter and for retransmitting them to a receiver.
BACKGROUND OF THE INVENTION
In mobile telephone systems, for example those known under the acronym GSM for “global system for mobile communications”, the user must be reachable regardless of location, and this must be possible particularly in a dense urban environment. To this end, the tops of certain buildings are fitted with transceiver “base” stations which communicate with users either directly if they are within the range of the antenna of the base station, or indirectly via active reflector antennas or “active repeaters” which, as their name implies, reflect radio signals transmitted by the nearby base station and vice versa for user returns to the base station.
Each reflecting antenna is in fact made up of two antennas, one having its radiation pattern pointing towards the base station and the other having its radiation pattern pointing towards the user, with the two antennas being interconnected by two electrical amplification paths, one for the station-to-user direction and the other for the user-to-station direction.
Such pairs of antennas suffer from the major drawback of having directional radiation patterns to avoid the risk of oscillation, thereby restricting the user coverage zone of such an antenna and increasing the number of reflective antennas that need to be used to cover a given zone. This gives rise to ever-increasing numbers of reflective antennas on the tops of buildings, thereby leading to higher overall cost.
OBJECT AND SUMMARY OF THE INVENTION
The object of the present invention is thus to provide an active repeater for a transmission system in which the repeater has a radiation pattern that is not very directional on reception and on transmission, and that uses a single transceiver antenna.
The invention thus provides an active repeater for a transmission system, the repeater comprising:
an antenna made up of a plurality of juxtaposed radiating elements which are grouped together in two separate identical matrix arrays; and
amplification paths for connecting each radiating element of one array to the radiating element of the other array having the same matrix position, with each amplification path having identical gain and phase shift so that the wave received by the first array at an angle of incidence &thgr; is retranmsitted by the second array as a wave having an angle of incidence &bgr; such that &thgr;=&bgr;.
The two radiating elements which are interconnected by an amplification path are far enough apart from each other to obtain isolation between the two radiating elements greater than the gain of the amplification path.
REFERENCES:
patent: 2880310 (1959-03-01), Jakes, Jr.
patent: 3390333 (1968-06-01), Klawsnik et al.
patent: 3731313 (1973-05-01), Nagai
patent: 3754258 (1973-08-01), Coleman
patent: 4806938 (1989-02-01), Meadows
patent: 5280297 (1994-01-01), Profera, Jr.
patent: 5392152 (1995-02-01), Higgins et al.
patent: 0 104 536 A2 (1984-04-01), None
patent: 2 471 679 (1981-06-01), None
Alcatel
Sughrue Mion Zinn Macpeak & Seas, PLLC
To Doris H.
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