Antenna assembly producing steerable beam and null

• US 4,017,867 A
• Filed: 02/25/1976
• Issued: 04/12/1977
• Est. Priority Date: 02/25/1976
• Status: Expired due to Term

• Current Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Original Assignee: Bell Telephone Laboratories, Inc. (Nokia Corporation)
• Inventors: Claus, Alfons Jozef
• Primary Examiner(s): Lieberman, Eli
• Application Number:
  US05/661,060
• Time in Patent Office: 412 Days
• Field of Search: 343/844, 343/853, 343/854, 343/100 SA, 340/6 R
• US Class Current: 342/368
• CPC Class Codes: H01Q 3/2617 Array of identical elements

Abstract

A prior art antenna ass embly comprises an array of elements, a steerable beamformer for producing a desired beam and a processor interconnecting the elements and the beamformer to introduce a steerable null. Presently disclosed is a processor which broadens the steerable null while not adversely affecting its low sensitivity character. This processor includes two or more beamformers uniquely related to one another and means for substracting combinations of their outputs from the various inputs to the steerable beamformer.

Claims

1. In an antenna assembly comprising

an array of antenna elements,

a steerable beamformer which when connected to said elements establishes a sensitivity pattern containing a steerable beam, and

a processor having input ports identifiable as 1 through n and output ports identifiable as 1 through n, said processor being connected between said elements and said steerable beamformer for reducing the sensitivity of said assembly in a steerable direction,

an improvement CHARACTERIZED IN THAT said processor comprises

at least two nonsteerable beamformers having their input ports connected in common,

means connected between said nonsteerable beamformer input ports and said processor input ports to steer a beam produced by a first of said nonsteerable beamformers in a desired direction,

said nonsteerable beamformers constructed so that said first nonsteerable beamformer establishes a sensitivity pattern with a single beam and each subsequent nonsteerable beamformer establishes a sensitivity pattern having a pair of beams whose axes of maximum sensitivity form an angle which includes all such angles formed by its predecessors,

a plurality of summers identifiable as 1 through n for summing predetermined portions of the outputs from said nonsteerable beamformers, and

means for subtracting the output of each of said summers from the input to the similarly identified processor input port and applying the difference to the similarly identified processor output port, whereby signals in said differences have the same phase relations with respect to one another as they have in said processor inputs.

2. An assembly in accordance with claim 1 in which

each of said nonsteerable beamformers comprises a plurality of amplifiers connected in series with its input ports, respectively, and a summer for summing the outputs of its amplifiers, and

each of said 1 through n summers comprises a plurality of amplifiers connected in series with its input ports, respectively, and means for summing the outputs of its amplifiers, the gain of each of said summer amplifiers being substantially equal to that of the amplifier which both is in the nonsteerable beamformer to which the summer amplifier is connected and is connected to the processor input port similarly identified as said summer containing said summer amplifier.

3. In an antenna assembly having a steerable null and a steerable beam in its sensitivity pattern where said assembly comprises

an array of antenna elements,

a steerable beamformer which when connected to said elements establishes a sensitivity pattern containing said steerable beam, and

a processor having input ports identifiable as 1 through n and output ports also identifiable as 1 through n, said processor being connected between said elements and said steerable beamformer, and furthermore, said processor comprising a nonsteerable beamformer, first means connected between said input ports and said nonsteerable beamformer for steering a beam in the sensitivity pattern established by said nonsteerable beamformer in the direction of said null, and second means for subtracting the output of said nonsteerable beamformer from each of the inputs applied to said input ports and applying the results thereof to said output ports corresponding to the input ports contributing to said results, said second means including delay means to cause the signals in said results to have the same phase relations with respect to one another as they have in said inputs,

an improvement CHARACTERIZED IN THAT said processor further comprises

at least a second nonsteerable beamformer having its input ports connected to the input ports of said first nonsteerable beamformer, said nonsteerable beamformers constructed so that said first nonsteerable beamformer establishes a sensitivity pattern with a single beam and each subsequent nonsteerable beamformer establishes a sensitivity pattern having a pair of beams whose axes of maximum sensitivity form an angle which includes all such angles of its predecessors, and

a plurality of summers, identifiable as 1 through n, for summing predetermined portions of the outputs from said nonsteerable beamformers and applying the summer outputs to said second means to subtract the output of each of said summers from said input on the similarly identified processor input port.

4. An assembly in accordance with claim 3 in which

each of said nonsteerable beamformers comprises a plurality of amplifiers connected in series with its input ports, respectively, and a summer for summing the outputs of its amplifiers, and

each of said 1 through n summers comprises a plurality of amplifiers connected in series with its input ports, respectively, and means for summing the outputs of its amplifiers, the gain of each of said summer amplifiers being substantially equal to that of the amplifier which both is in the nonsteerable beamformer to which the summer amplifier is connected and is connected to the processor input port similarly identified as said summer containing said summer amplifier.