Cellular antenna
An antenna for communicating with mobile devices in a land-based cellular communication system via an antenna beam having a width, azimuth angle and downtilt angle. The antenna includes: a two dimensional array of radiating elements ( 31 - 34 ); and a feed network ( 35 - 39 ) from a feed line to the radiating elements. The feed network includes: downtilt phase shifting means ( 35,36 ) for varying the phase of signals supplied to or received from the radiating elements so as to vary the downtilt angle of the antenna beam; azimuth phase shifting ( 38,39 ) means for varying the phase of signals supplied to or received from the radiating elements so as to vary the azimuth angle of the antenna beam; and beam width adjustment means ( 37 ) for varying the power or phase of signals supplied to or received from the radiating elements so as to vary the width of the antenna beam.
1. An antenna for communicating with mobile devices in a land-based cellular communication system via an antenna beam having a width and an angle, the antenna including:
a plurality of radiating elements; and
a feed network from a feed line to the radiating elements, the feed network including:
adjustable power dividing means for varying the division of power between radiating elements so as to vary the width of the antenna beam;
adjustable phase shifting means for varying the phase of signals supplied to or received from the radiating elements so as to vary the angle of the antenna beam; and
a land-base antenna system including one or more antennas;
control means adapted to provide signals to the antenna(s) to adjust a characteristic of the antenna beam;
wherein the control means includes:
means for receiving a command to change a beam characteristic of one of the antennas;
means for calculating the beam characteristics required for all of the antennas to achieve a desired coverage; and
means for adjusting one or more beam characteristic of each antenna as required to achieve the desired coverage.
2. The antenna of claim 1 wherein the power dividing means divides power between one or more central radiating elements and two or more outer radiating elements positioned on opposite sides of the central radiating element(s).
3. The antenna of claim 2 wherein the phase shifting means adjusts the relative phase between the pair of outer radiating elements.
4. The antenna of claim 3 wherein the phase relationship between the central radiating element(s) and the power dividing means is substantially fixed for all values of beam angle.
5. The antenna of claim 2 wherein the angle is an azimuth angle.
6. The antenna of claim 2 wherein the angle is a downtilt angle.
7. The antenna of claim 2 wherein the phase shifting means can vary the azimuth and downtilt angle of the antenna beam.
8. The antenna of claim 1 wherein the power dividing means is substantially non-attenuating.
9. The antenna of claim 1 wherein the or each phase shifting means is adjusted by varying the relative position of two or more phase shifting components.
10. A land-based antenna system including one or more antennas according to claim 1 and an encoder for encoding downlink signals for transmission to the radiating elements according to a code-division multiplexing (CDMA) scheme.
11. The land-based antenna system of claim 10 including control means adapted to provide signals to the antenna(s) to adjust a characteristic of the antenna beam.
12. The system of claim 11 wherein the control means includes:
graphical user interface means for graphically displaying parameters of the configuration of a plurality of antennas wherein, via use of an input device, the graphical elements may be manipulated to adjust parameters of the configuration; and
communication means for sending control signals to an actuation means to adjust parameters of an antenna in accordance with those displayed by the graphical user interface.
13. A land-based cellular communication system including one or more systems according to claim 10 , and a remote control center for issuing commands to each system to adjust antenna beam characteristics of each system.
14. A land-based antenna system including one or more antennas according to claim 1 , and a decoder for decoding uplink signals received from the radiating elements according to a code-division multiplexing (CDMA) scheme.
15. The system of claim 1 wherein the control means comprises a local receiver adapted to receive commands from a remote control center.
16. An antenna system as claimed in claim 1 , further comprising:
control means for driving electromechanical means associated with each phase shifting means wherein the control means includes processing means to control the antenna in accordance with control data supplied thereto.
17. The antenna of claim 1 wherein the power dividing means includes:
an adjustable phase shifter for adjusting the relative phase between signals on a pair of signal lines; and
a hybrid coupler which is coupled to the pair of signal lines.
18. The antenna of claim 17 wherein the adjustable phase shifter adjusts the length of one of the pair of signal lines compared to the length of the other signal line.
19. The antenna of claim 17 wherein the hybrid coupler is a 90 degree hybrid coupler.
20. The antenna of claim 17 wherein the power coupler further includes a splitter/combiner coupled to the pair of signal lines.
21. The antenna of claim 20 wherein the splitter/combiner is a hybrid coupler.
22. The antenna of claim 21 wherein the splitter/combiner is a 90 degree hybrid coupler.
23. An antenna system as claimed in claim 1 , wherein control signals are provided to the antenna(s) over a wireless link.