Time-multiplexed phased-array antenna beam switching system
First Claim
1. A time multiplexed opto-electronic signal control system for processing an optical input signal having a predetermined polarization, comprising:
- an opto-electronic signal processing system comprising at least a first and a second signal processing channel, said first and second channel each being adapted to selectively receive said optical input signal and generate a respective channel optical output signal, each of said channels further comprising a plurality of relatively slow speed optical processing devices sequentially coupled together, each of said optical processing devices being adapted to be individually selectively controlled to cumulatively generate respective time-delayed channel optical output signals from each channel; and
time multiplexing means for rapidly switching between respective ones of said signal processing channels to select an active channel to produce a control system output signal comprising sequential ones of active channel output signals and having a relatively short dead time between said sequential active channel output signals;
each of said plurality of relatively slow speed optical processing devices in the non-active channel being adapted to be controlled independently of and concurrently with the operation of said optical processing devices in said active channel to establish an optical configuration to process the next sequential system output signal.
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Accused Products
Abstract
An optical control system for a phased-array antenna system employs a time-multiplexed optical control architecture to provide very fast (a few hundred beams per second) antenna beam scanning using slow (milliseconds) response spatial light modulators in two optical signal processing channels. In each channel a cascade of relatively slow switching speed nematic liquid crystal cell spatial light modulators and associated free space delay units or fiber optic delay cables are disposed to receive transmit or receive optical input signals comprising a plurality of light beams. The control voltages applied to the spatial light modulators determine the paths of the light beams through the cascade and the differential time delay imparted to the light beams in the input optical signal. High speed 90° polarization rotators control the polarization of the transmit and receive optical input signals and the polarization of optical signals passing from the cascade, allowing for selecting the active channel and the transmit or receive mode of the active channel, thus enabling sequential rapid beam scans of the radar with a relatively short dead time between respective transmit/receive sequences. The spatial light modulators in the non-active channel are reconfigured during the dwell time of the active channel to set up for the next transmit/receive sequence.
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Citations
28 Claims
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1. A time multiplexed opto-electronic signal control system for processing an optical input signal having a predetermined polarization, comprising:
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an opto-electronic signal processing system comprising at least a first and a second signal processing channel, said first and second channel each being adapted to selectively receive said optical input signal and generate a respective channel optical output signal, each of said channels further comprising a plurality of relatively slow speed optical processing devices sequentially coupled together, each of said optical processing devices being adapted to be individually selectively controlled to cumulatively generate respective time-delayed channel optical output signals from each channel; and time multiplexing means for rapidly switching between respective ones of said signal processing channels to select an active channel to produce a control system output signal comprising sequential ones of active channel output signals and having a relatively short dead time between said sequential active channel output signals; each of said plurality of relatively slow speed optical processing devices in the non-active channel being adapted to be controlled independently of and concurrently with the operation of said optical processing devices in said active channel to establish an optical configuration to process the next sequential system output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A phased array antenna system comprising:
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a plurality of antenna elements arranged in an array, said array being operable in a transmit or a receive mode; an optical signal processing system coupled to said array and having a plurality of input and output signal paths corresponding to respective transmit and receive sequences of said array, said system being adapted to generate differentially time-delayed optical control signals to control output beam radiation patterns transmitted from said array and to optically process return radiation patterns detected by said array in each of said transmit and receive sequences, said system comprising at least a first and a second signal processing channel each comprising a plurality of relatively slow speed optical processing devices, each of said optical processing devices being adapted to be individually selectively controlled to cumulatively generate a respective channel optical output signal; a modulated laser source optically coupled to said signal processing system to provide an optical input transmit signal having selected characteristics of wavelength, intensity, and modulation, said laser source including means for dividing said optical input transmit signal into a plurality of transmit light beams; an optoelectronic transceiver array to convert the transmit optical control signals into electric array control signals and to convert electrical signals generated by the antenna array in response to return radiation patterns into optical input receive signals comprising a plurality of receive light beams; and time multiplexing means for rapidly switching between said signal processing channels to provide rapid shifting between a transmit and receive sequence of one of said channels and a transmit and receive sequence of the other of said channels with a relatively short dead time therebetween, said slow speed optical processing devices each being adapted to be individually selectively controlled to configure a respective channel to generate a predetermined transmit and receive sequence control signal during the transmit and receive sequence of the other respective channel. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method of processing optical signals to control a phased array antenna having a plurality of antenna elements, comprising the steps of:
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causing said phased array antenna to emit and receive electromagnetic radiation along a selected beam path in a predetermined transmit and receive sequence having a selected dwell time; and time multiplexing the operation of an antenna array control system having at least two signal processing channels to switch rapidly between said channels to select respective transmit and receive sequences to drive said phased array antenna to produce relatively short dead times between the dwell times of the respective transmit and receive sequences; wherein the step of time multiplexing the operation further comprises configuring a plurality of channel optical signal processing devices in the non-driving signal processing channel during the dwell time of the driving channel. - View Dependent Claims (25, 26, 27, 28)
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Specification