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US 4,387,378 AGranted
Antenna having electrically positionable phase center
AssigneeHarris Corporation
InventorAlbert S. Henderson
Life of this patent
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AssigneeHarris Corporation
InventorAlbert S. Henderson
Estimating the term…
An antenna (50) is disclosed herein whose phase center may be electrically moved relative to a main receiving/radiating element. The main receiving element (56) is located in a cavity (54) in a ground plane (52). Spaced around the main receiving element are a number of paracletic elements (58, 60, 62, 64), each of which has at least two switchable reactance states. In one state, there is little coupling between the paracletic element and the main receiving element. In another state, coupling is increased so that the phase center of the antenna shifts towards the paracletic element. A sequencer (100) supplies bias voltages to switching diodes (84, 86) to control the reactance states of the paracletic elements and thus the position of the phase center of the antenna. The antenna may be used as a tracking feed (14) for a directional lens or reflector system (12).
A tracking antenna including electromagnetic energy directing means for directing electromagnetic energy to or from a vertex, and a tracking feed located at said vertex, said tracking feed comprising primary radiating/receiving means for receiving or transmitting electromagnetic energy and having a unidirectional radiating pattern, a plurality of paracletic means fixedly positioned about said unidirectional radiating pattern of said primary radiating/receiving means, each having at least two selectable impedance states for controllably shifting the position of the phase center of said tracking feed relative to said directing means, and means for controlling said impedance states of said plurality of paracletic means so as to shift the position of said phase center in a known manner, whereby a signal received by said primary radiating/receiving means is modulated by said controlled phase center shifting and may be processed to derive tracking information therefrom.
An antenna comprising
Apparatus comprising:
Apparatus comprising:
Apparatus comprising electromagnetic energy directing means for focusing electromagnetic energy at a vertex, a feed antenna having a directional amplitude pattern, said feed antenna being disposed at said vertex and pointed so that said energy directing means is disposed within said pattern, non-parasitic reactance means for electromagnetically interacting with said feed antenna to shift its phase center by an amount dependent upon the reactance of said reactance means, said reactance means having a controllable reactance, and control means for controlling the reactance of said reactance means so as to shift the position of said phase center in a known manner, whereby a signal received by said feed antenna is modulated in accordance with said controlled phase center shifting.
Apparatus comprising:
Dependencies are inferred from the claim text.