Multiple-beam antenna system with active modules and digital beam-forming

• US 5,034,752 A
• Filed: 06/27/1990
• Issued: 07/23/1991
• Est. Priority Date: 07/04/1989
• Status: Expired due to Fees

• Current Assignee: Thomson-CSF
• Original Assignee: Thomson-CSF
• Inventors: Roger, Joseph, Pourailly, Jean-Louis
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/544,321
• Time in Patent Office: 391 Days
• Field of Search: 342/373, 342/149, 342/154
• US Class Current: 342/373
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 25/00 Antennas or antenna systems providing at least two radiating patterns arrangements for changing or varying the orientation or the shape of the directional pattern H01Q3/00
• CPC Class Codes: H01Q 3/26 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 H01Q3/12, H01Q3/22, H01Q3/24 take precedence

Abstract

Such a system typically comprises: a plurality of elementary antennas configured in an array, each having an associated active module, a plurality of DBF modules, each receiving a microwave signal coming from the active modules and delivering complex digital data (I, Q) representing the input signal; and DBF processor means preparing weighted sums on the basis of this complex digital data, the weighting corresponding to a reception channel defining a narrow beam of the radiation pattern of the antenna. The system further comprises a plurality of prefiltering spatial circuits, each of which receives a plurality of signals coming from the active module and delivers, to an associated DBF module, a signal which is a sum, weighted in amplitude, of certain of the signals received at input, each DBF module being thus associated with a sub-array, the different sub-arrays thus forming being imbricated with one another and the weighting being chosen so that the pattern of the sub-array is a sectoral pattern that essentially lets through only the signals coming from a restricted zone of space. The number of spatial prefiltering circuits and DBF modules is smaller than that of the elementary antennas, and the processor means simultaneously process the outputs signals from the spatial prefiltering circuits so as to obtain, for the radiation pattern of the antenna, an equivalent number of simultaneous, distinct beams of homogeneous quality.

Claims

1. A digital beam-forming antenna with active modules comprising:

a plurality of elementary antennas configured in an array;

a plurality of amplifier active modules, equal in number to the elementary antennas and each associated, respectively, with one of these modules;

a plurality of spatial prefiltering circuits, each of which has a plurality of inputs each connected to one of said active modules and an output delivering a signal which is a sum, weighted in amplitude, of the signals received at input;

a plurality of DBF modules, each having an input connected to the output of a respective prefiltering circuit and two outputs giving, in digital form, complex data I, Q representing the signal received at input, each of said DBF modules being thus associated with a sub-array of the array of said elementary antennas, the different sub-arrays thus formed being interleaved with one another and the weighting of the signals of each sub-array being chosen so that its pattern is a sectoral pattern essentially letting through only the signals coming from a restricted zone of space, the number of said spatial prefiltering circuits as well as said DBF modules associated with them being smaller than the number of elementary antennas; and

DBF processor means using the complex digital data delivered by said DBF modules to prepare weighted sums of this data according to predetermined weightings to obtain, for the radiation pattern of the antenna, a plurality of distinct, simultaneous and narrow beams.

2. The antenna system of claim 1, wherein the weighting achieved by the DBF processor means is an adaptive weighting providing for the convergence of aiming in a desired spatial direction.

3. A digital beam-forming antenna with active modules comprising:

a plurality of elementary antennas configured in an array;

a plurality of amplifier active modules, equal in number to the elementary antennas and each associated, respectively, with one of these modules;

a plurality of DBF modules, equal in number to the active modules and each associated, respectively, with one of these modules, each receiving the microwave signal coming from the active module and delivering, at output, complex digital data (I, Q) representing the signal received at input;

spatial prefiltering circuits having a plurality of inputs receiving said digital data from said DBF modules and a plurality of outputs to deliver weighted sums of at least certain of the digital data received at input, so as to form sub-arrays of the array of elementary antennas, the different sub-arrays thus formed being imbricated with one another and the weighting of the signals of each sub-array being chosen so that its pattern is a sectoral pattern essentially letting through only the signals coming from a restricted zone of space; and

DBF processor means using the complex digital data delivered by said DBF modules of the system to prepare weighted sums of these data according to predetermined weightings to obtain, for the radiation pattern of the antenna, a plurality of distinct, simultaneous and narrow beams.

4. The antenna system of claim 3, wherein the weighting done by the DBF processor means is an adaptive weighting that provides for the convergence of aiming in a desired spatial direction.