Fiber optic feed network for radar
First Claim
1. In a radar having electrical transmitting and receiving circuitry and a phased array antenna having a plurality of radiating elements for the radiation of microwave signals, a feed system coupling the antenna with the transmitting and receiving circuitry, the feed system comprising:
- beamforming means for processing microwave signals to steer the antenna beam and making those signals available at a plurality of input/output ports;
a plurality of optical fibers, each of which is for exclusively coupling signals between a particular input/output port of the beamforming means and a particular radiating element of the antenna;
multiplexing means at opposite ends of each of said fibers for two-way communication of optical signals;
a plurality of electro-optic modulating means one each coupled to input terminals of said multiplexing means for applying optical signals modulated by an electric waveform;
a plurality of photoelectric detecting means one each coupled to output ports of said multiplexing means for detecting electric waveforms in an optical signal applied to the multiplexing means; and
sources of optical radiation, said sources differing in frequency and being coupled to respective input ports of said modulating means to permit separation of respective ones of optical signals applied to said optical fibers by said multiplexing means, and wherein said modulating means connecting with said input/output ports of said beamforming means for modulating optical radiation with transmit signals, said photoelectric detecting means connecting with elements of said antenna for exciting said elements with electric signals having the transmit waveform.
3 Assignments
0 Petitions
Accused Products
Abstract
In a radar having electrical transmitting and receiving circuitry, and an antenna for the radiation of microwave signals, there is provided an optical feed system which couples the antenna with the transmitting and receiving circuitry. The feed system includes a set of optical multiplexers interconnected by sets of optical fibers. Microwave energy of the radar is converted to optical radiation for communication to the antenna, and then converted back to the microwave energy. Electro-optic modulators and photoelectric detectors provide for the energy conversion. A plurality of signals, including both signals having the transmit waveform as well as control signals, can be simultaneously coupled via the optical fibers by utilization of radiation of differing frequencies. The multiplexers include dichroic mirrors for separation of the radiations of the differing frequencies. The fiber optic feed system retains the full beam steering capacity of the radar and permits the use of conventional electronic circuitry with the feed network of the optical feed system.
-
Citations
20 Claims
-
1. In a radar having electrical transmitting and receiving circuitry and a phased array antenna having a plurality of radiating elements for the radiation of microwave signals, a feed system coupling the antenna with the transmitting and receiving circuitry, the feed system comprising:
-
beamforming means for processing microwave signals to steer the antenna beam and making those signals available at a plurality of input/output ports; a plurality of optical fibers, each of which is for exclusively coupling signals between a particular input/output port of the beamforming means and a particular radiating element of the antenna; multiplexing means at opposite ends of each of said fibers for two-way communication of optical signals; a plurality of electro-optic modulating means one each coupled to input terminals of said multiplexing means for applying optical signals modulated by an electric waveform; a plurality of photoelectric detecting means one each coupled to output ports of said multiplexing means for detecting electric waveforms in an optical signal applied to the multiplexing means; and sources of optical radiation, said sources differing in frequency and being coupled to respective input ports of said modulating means to permit separation of respective ones of optical signals applied to said optical fibers by said multiplexing means, and wherein said modulating means connecting with said input/output ports of said beamforming means for modulating optical radiation with transmit signals, said photoelectric detecting means connecting with elements of said antenna for exciting said elements with electric signals having the transmit waveform. - View Dependent Claims (2, 3, 4, 5)
-
-
6. In an electronically steerable phased array radar having a beamformer with input/output ports and an antenna, the beamformer for processing microwave signals including means for delaying signals coupled to individual radiators of the antenna, an optical feed system for coupling signals from the beamformer to the antenna, the optical feed system comprising:
-
a set of optical transmission paths connecting respective input/output ports of the beamformer with respective ones of the antenna radiators; a plurality of first converting means one each connected between respective input/output beamformer ports and said respective transmission paths for converting electric signals of said beamformer to optical signals, said optical signals propagating along said respective transmission paths toward said antenna; and a plurality of second converting means one each connected between said respective antenna radiators and said respective transmission paths for converting optical signals to electric signals, for radiation from said radiators as the radar transmitted signal. - View Dependent Claims (7, 11)
-
-
8. In an electronically steerable array antenna having a beamformer for processing microwave signals which is spaced apart from radiating elements of the antenna, an optical feed system for coupling signals between said beamformer to said radiating elements comprising:
-
a set of optical transmission paths disposed between said beamformer and said radiating elements for exclusively coupling respective input/output ports of the beamformer to respective radiating elements; a plurality of multiplexing means one each connecting with said set of optical transmission paths for providing two-way transmission of optical signals along said transmission path; and a plurality of converting means one each coupled to said transmission paths for providing a conversion between optical energy and electric energy whereby electric signals of said beamformer and said respective radiating elements can be converted to optical signals for transmission along said transmission paths followed by conversion back to electric signals. - View Dependent Claims (9, 10)
-
-
12. In a radar system having electrical transmitting and receiving circuitry and a phased array antenna in which the plurality of radiating elements are connected to respective transmit/receive modules, a feed system coupling the transmit/receive modules with the transmitting and receiving circuitry comprising:
-
beamforming means for processing microwave transmit and received signals to steer the antenna beam and making the processed transmit signals available at a plurality of input/output ports; a plurality of optical fibers, each of which is for exclusively coupling signals between a particular input/output port of the beamforing means and a particular transmit/receive module; optical source means for producing optical radiation for conduction by the plurality of optical fibers; a plurality of electro-optic modulating means, each of which is for coupling an optical fiber to the optical radiation and for modulating that radiation by applying the processed transmit signal from the respective input/output port of the beamforming means thereto; and a plurality of photoelectric detecting means, each of which is coupled to a respective optical fiber, for detecting electrical transmit signals in an optical signal conducted by the optical fibers and applying the detected transmit signals to the respective transmit/receive module. - View Dependent Claims (13, 14, 15, 16, 17)
-
-
18. In a radar system having electrical receiving circuitry and a phased array antenna in which the plurality of radiating elements are connected to respective transmit/receive modules, a feed system coupling the transmit/receive modules with the receiving circuitry comprising:
-
beamforming means for processing microwave received signals to steer the antenna beam and for receiving the received signals at a plurality of input/output ports; a plurality of optical fibers, each of which is for exclusively coupling signals between a particular input/output port of the beamforming means and a particular transmit/receive module; optical source means for producing optical radiation for conduction by th plurality of optical fibers; a plurality of electro-optic modulating means, each of which is for coupling an optical fiber to the optical radiation and for modulating that radiation by applying the received signal from the respective transmit/receive module thereto; and a plurality of photoelectric detecting means, each of which is coupled to a respective optical fiber, for detecting electrical received signals in an optical signal conducted by the optical fibers and applying the detected received signals to the respective input/output port of the beamforming means. - View Dependent Claims (19, 20)
-
Specification