Reconfigurable parasitic control for antenna arrays and subarrays
First Claim
1. A reconfigurable RF antenna array comprising:
- a plurality of antenna elements spatially distributed over an array aperture;
wherein at least two of said antenna elements each comprise at least one driven component, and at least one of said antenna elements is a controlled parasitic antenna element that has a largest dimension of about one-half wavelength at the lowest frequency of its operational bandwidth and contains within its radiating aperture (a) at least one driven component, (b) at least one parasitic component, and (c) at least one controllably variable reactance load connected to said at least one parasitic component; and
an array controller connected to said at least one variable reactance load to control the electromagnetic properties of said at least one controlled parasitic antenna element and thereby to control, at least in part, a predetermined characteristic of said array.
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Accused Products
Abstract
Reconfiguration of parasitically controlled elements in a phased array is used to expand the range of operational functions. Embedded array elements can be frequency tuned, and bandwidth can be improved by using reconfiguration to broaden the bandwidth of the embedded elements. For high gain arrays, beam squint can be a limiting factor on instantaneous bandwidth. Reconfiguration can alleviate this problem by providing control of the element phase centers. Scan coverage can be improved and scan blindness alleviated by controlling the embedded antenna patterns of the elements as well as by providing control of the active impedance as the beam is scanned. Applying limited phase control to the elements themselves can alleviate some of the complexity of the feed manifold. A presently preferred method of designing reconfigurable antennas is to selectively place controlled parasitic elements in the aperture of each of the antenna elements in the phased array. The parasitic elements can be controlled to change the operational characteristics of the antenna element. The parasitic elements are controlled by either switching load values in and out that are connected to the parasitic elements or are controlled by applying control voltages to variable reactance circuits containing devices such as varactors. The parasitic elements can be controlled by the use of a feedback control subsystem that is part of the antenna system which adjusts the RF properties of the parasitic components based on some observed metric. The controllable characteristics include directivity control, tuning, instantaneous bandwidth, and RCS.
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Citations
26 Claims
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1. A reconfigurable RF antenna array comprising:
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a plurality of antenna elements spatially distributed over an array aperture; wherein at least two of said antenna elements each comprise at least one driven component, and at least one of said antenna elements is a controlled parasitic antenna element that has a largest dimension of about one-half wavelength at the lowest frequency of its operational bandwidth and contains within its radiating aperture (a) at least one driven component, (b) at least one parasitic component, and (c) at least one controllably variable reactance load connected to said at least one parasitic component; and an array controller connected to said at least one variable reactance load to control the electromagnetic properties of said at least one controlled parasitic antenna element and thereby to control, at least in part, a predetermined characteristic of said array. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for controlling at least one predetermined characteristic of a reconfigurable RF antenna array, said method comprising:
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arranging a plurality of antenna elements spatially distributed over an array aperture; wherein at least two of said antenna elements each comprise at least one driven component, and at least one of said antenna elements is a controlled parasitic antenna element that has a largest dimension of about one-half wavelength at the lowest frequency of its operational bandwidth and contains within its radiating aperture (a) at least one driven component, (b) at least one parasitic component, and (c) at least one controllably variable reactance load connected to said at least one parasitic component; and controlling changes in at least said at least one variable reactance loads thereby to control the electromagnetic properties of said at least one controlled parasitic antenna element and thereby control, at least in part, a predetermined characteristic of said array. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A method for providing a reconfigurable RF antenna array, said method comprising:
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co-locating at least one reactively-controlled parasitic component with at least one driven component within an antenna element radiating aperture having a largest dimension of about one-half wavelength at the lowest frequency of its operational bandwidth for at least one of plural radiating antenna apertures having a driven component in a phased array of radiating antenna element apertures; and controlling said parasitic components by changing the value of a reactance connected thereto to change operational characteristics of the corresponding co-located driven and parasitic antenna components for said at least one of plural radiating apertures in said array to control, at least in part, a predetermined characteristic of said array. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26)
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Specification