Array antennas with notched radiation patterns
AssigneeBAE System Aerospace Inc.
InventorsAlfred R. Lopez, Henry L. Bachman
Life of this patent
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Abstract
A source of interference signals may be present at a fixed incident angle relative to a stationary antenna. Horizontal array antennas are provided with radiation pattern notches or nulls at selected fixed angles to suppress reception of interference signals. By excitation of elements on the left side of an array in opposite phase relative to elements on the right side and provision of an appropriate line-length differential between left and right radiation element feed lines, a radiation pattern notch is positioned at a selectable angle relative to boresight. Notch width optimization is provided by use of relative excitation levels of radiating elements as disclosed. Other configurations are disclosed.
Claims18
An array antenna, to provide sector coverage with a radiation pattern notch at a selected angle (Θ) within the sector, comprising:
- a horizontal linear array of radiating elements including at least one left-side element and at least one right-side element, all left-side elements arranged for nominally opposite-phase excitation relative to all right-side elements;
- a power divider/combiner;
- and
- left and right coupling lines respectively coupled between the power divider/combiner and the left-side and right-side elements, including a left coupling line having a line-length differential (LL-LR) relative to a right coupling line, said line-length differential selected to provide a phase differential between excitation of left-side and right-side elements to modify said nominally opposite-phase excitation to produce said radiation pattern notch at the selected angle (Θ), relative to array boresight.
An array antenna, to provide sector coverage with a radiation pattern notch at a selected angle (Θ) within the sector, comprising:
- a horizontal linear array of radiating elements including at least one left-side element and at least one right-side element;
- a power divider/combiner;
- and
- left and right coupling lines respectively coupled between the power divider/combiner and the left-side and right-side elements, including a left coupling line having a line-length differential (LL-LR) relative to a right coupling line, said line-length differential selected to provide a phase differential between excitation of left-side and right-side elements to produce said radiation pattern notch at the selected angle Θ, relative to array boresight.
An array antenna, to provide sector coverage with a radiation pattern notch at a selected angle (Θ) within the sector, comprising:
- a horizontal linear array of radiating elements including at least one left-side element and at least one right-side element, all left-side elements arranged for nominally opposite-phase excitation relative to all right-side elements;
- a power divider/combiner;
- and
- left and right coupling lines respectively coupled between the power divider/combiner and the left-side and right-side elements, including a left coupling line having a line-length differential (LL-LR) relative to a right coupling line, said line-length differential selected to provide a phase differential between excitation of left-side and right-side elements to modify said nominally opposite-phase excitation to produce said radiation pattern notch at the selected angle (Θ), relative to array boresight, where nominally θ = sin - 1 ( L R - L L D )
- with D equal to the lateral spacing between adjacent radiating elements.
Dependencies are inferred from the claim text.