Steerable beam antenna system using butler matrix
US4882588A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 14, 1988 |
| Grant date | Nov 21, 1989 |
| Priority date | — |
| Expiry date | Nov 14, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B7/2041
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A steerable beam antenna system for use in satellite communication systems and including a main reflector and an antenna array having a plurality of feed elements is disclosed. The antenna array is positionable at or near at least one focal point of the main reflector, and its feed elements can receive microwaves from or transmit microwaves toward the main reflector. A Butler matrix having multiple input ports and multiple outputs is connected to the array of feed elements and substantially performs a spatial Fourier transformation on a generated set of signals to be transmitted which have a predetermined phase relationship between the signals, which is necessary to create the steerable beam. The Butler matrix also can perform an inverse spatial transformation on a set of incoming signals focused on the array by the reflector and received by the feed elements. By using a Butler matrix, the antenna system of the present invention is able to communicate with multiple ground stations simultaneously and with high gain using many virtual spot beams, each oriented to a distinct location on the earth that is dependent on the relative frequency of the beam.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.