Method for reducing side lobes in antenna patterns

• US 5,252,983 A
• Filed: 08/24/1992
• Issued: 10/12/1993
• Est. Priority Date: 09/11/1991
• Status: Expired due to Term

• Current Assignee: National Space Development Agency of Japan
• Original Assignee: National Space Development Agency of Japan
• Inventors: Sezai, Toshihiro
• Primary Examiner(s): Blum, Theodore M.
• Application Number:
  US07/933,673
• Time in Patent Office: 414 Days
• Field of Search: 342/382
• US Class Current: 342/382
• CPC Class Codes: G01K 11/006 using measurement of the effect of a material on microwaves or longer electromagnetic waves, e.g. measuring temperature via microwaves emitted by the object G01K17/003, G01J5/00 take precedence; measuring the effect of a material on X-, gamma- or particle radiation G01K11/30
• CPC Class Codes: G01S 7/2813 Means providing a modification of the radiation pattern for cancelling noise, clutter or interfering signals, e.g. side lobe suppression, side lobe blanking, null-steering arrays specially adapted to secondary radar systems G01S13/762; aerials or aerials systems H01Q21/29, H01Q25/00
• CPC Class Codes: H01Q 21/296 Multiplicative arrays

Abstract

A method for reducing side lobes wherein an antenna system comprises a main antenna and a sub antenna which does not have an isotropic antenna pattern in a direction (X direction) of an orientation of a side lobe of the main antenna to be reduced which is arranged in such a way that the sub antenna adjoins the main antenna in the direction (Y direction) perpendicular to the X direction and the beam axis of the sub antenna coincides with the beam axis of the main antenna; wherein an antenna beam of the antenna system is scanned in the X direction and a signal received with the main antenna is multiplied by a signal received with the sub antenna on the condition that phases of both signals coincide with each other.

Claims

1. A method for reducing side lobes in an antenna pattern, comprising the steps of:

(a) providing an antenna system which includes;

a main antenna for receiving radio waves; and

at least one sub antenna which does not have an isotropic antenna pattern in a first direction coinciding with the orientation of a side lobe of said main antenna to be reduced, said at least one sub antenna being arranged such that said at least one sub antenna adjoins said main antenna in a second direction perpendicular to said first direction and a beam axis of each said at least one sub antenna coincides with a beam axis of said main antenna;

(b) scanning an antenna beam in said first direction with said antenna system; and

(c) multiplying a signal received with said main antenna by signals received with said at least one sub antenna as long as phases of each of these signals coincide with each other.

2. A method for reducing side lobes in an antenna pattern as defined in claim 1, wherein said step of providing an antenna system includes providing a plurality of said sub antennas, and wherein said step of multiplying includes the steps of adding together each signal received with each said sub antenna and then multiplying the resultant added signal by said signal received with said main antenna.

3. A method for reducing side lobes in an antenna pattern as defined in claim 1, wherein said step of providing an antenna system includes providing a plurality of said sub antennas, and wherein said step of multiplying includes the steps of sequentially multiplying each signal received with each said sub antenna by said signal received with said main antenna.

4. A method for making a reduction in a beam width in addition to a reduction in side lobes in an antenna pattern, comprising the steps of:

(a) providing an antenna system which includes;

a main antenna for receiving radio waves; and

at least one sub antenna which does not have an isotropic antenna pattern in a first direction coinciding with an orientation of a side lobe of aid main antenna to be reduced, said at least one sub antenna being arranged such that said sub antenna adjoins said main antenna in a second direction perpendicular to said first direction and a beam axis of each said at least one sub antenna coincides with a beam axis of said main antenna;

(b) scanning an antenna beam in a direction other than either the first direction or the second direction with said antenna system; and

(c) multiplying a signal received with said main antenna by signals received with said at least one sub antenna as long as phases of each of these signals coincide with each other.

5. A method for making a reduction in a beam width in addition to a reduction in side lobes in an antenna pattern as defined in claim 4, wherein said step of providing an antenna system includes providing a plurality of said sub antennas, and wherein said step of multiplying further includes the steps of adding together each signal received with each said sub antenna and then multiplying the resultant added signal by the signal received with said main antenna.

6. A method for making a reduction in a beam width in addition to a reduction in side lobes in an antenna pattern as defined in claim 4, wherein said step of providing an antenna system includes providing a plurality of said sub antennas, and wherein said step of multiplying includes the steps of sequentially multiplying each signal received with each said sub antenna by said signal received with said main antenna.