Phased-array mapping for beamspace processing and beamspace processor
An apparatus and method is provided to correlate radiation beams, such as RF beams, optical beams, and/or acoustic beams. A plurality of sensors are distributed according to a first pattern and disposed adjacent to a first interference region. The plurality of sensors may capture incoming radiation and convert the incoming radiation to a plurality of signals. A plurality of radiating elements are distributed according to a second pattern that differs from the first pattern and are disposed adjacent to a second interference region. A plurality of channels are connected between the sensors and the radiating elements, each channel connecting a corresponding sensor to receive a corresponding signal. Each of the radiating elements is in communication with a corresponding one of the plurality of channels to provide an outgoing radiation corresponding to the signal received by the channel. The second pattern has a relationship to the first pattern such that first and second beams of incoming radiation in the first interference region captured by the plurality of sensors are respectively mapped to corresponding first and second beams of outgoing radiation emitted by the plurality of radiating elements into the second interference region.
1. An RF transmitter, comprising:
an interference space configured to receive N modulated optical signals transmitted at a first edge of the interference space to a second edge of the interference space, the N modulated optical signals forming N optical beams in the interference space that are superimposed with each other at the second edge of the interference space;
a plurality of channels at the second edge of the interference space to capture the N optical beams as corresponding virtual beams within the channels;
a plurality of photodetector each in communication with a corresponding channel to convert an optical signal received by the corresponding channel to a corresponding RF electrical signal; and
an antenna array comprising a plurality of antenna elements each connected to a corresponding photodetector and configured to receive the corresponding RF electrical signal of the photodetector to generate a corresponding electromagnetic RF signal,
wherein N is an integer greater than 1,
wherein the antenna elements of the antenna array are arranged in a first pattern, and
wherein ends of the channels are positioned at the second edge of the interference space and are arranged in a second pattern that is different from the first pattern.
2. The RF transmitter of claim 1 ,
wherein the antenna array is configured to emit N RF beams in response to the RF electrical signals provided by the photodetectors,
where each of the N modulated optical signals corresponds to a different one of the N RF beams.
3. The RF transmitter of claim 2 ,
wherein the antenna elements are arranged in a two dimensional (2D) array as the first pattern, and
wherein the ends of the channels are arranged in a one dimensional (1D) array as the second pattern.
4. The RF transmitter of claim 3 , further comprising N optical waveguides having ends at the first edge of the interference space and configured to transmit the N modulated optical signals into the interference space,
wherein the ends of the N optical waveguides at the first edge of the interference space are arranged in a one dimensional array.
5. The RF transmitter of claim 4 , further comprising electro optic modulators configured to generate the N modulated optical signals and provide the N modulated optical signals to the interference space via the N optical waveguides.
6. The RF transmitter of claim 3 , wherein the second arrangement of the ends of the channels has a relationship with the first arrangement of the plurality of antennas such that the locations of the ends of the N optical waveguides at the first edge of the interference space determine respective propagation directions of corresponding RF beams emitted by the antenna array.
7. The RF transmitter of claim 3 , wherein the ends of the channels are arranged along a curved line.
8. The RF transmitter of claim 3 , the ends of the channels are arranged along a line that lies within a first plane and each of the N modulated optical propagate in a direction along the first plane.
9. The RF transmitter of claim 3 , wherein at least the channels and the interference space are formed in a first semiconductor chip, wherein propagation directions of the optical signals in the channels and propagation directions of the N modulated optical signals in the interference space are in directions parallel to the upper surface of a substrate of the first semiconductor chip.
10. The RF transmitter of claim 3 , further comprising a processor configured to encode information into each of the N modulated optical signals, the encoded information of each of the N modulated optical signals being provided with a corresponding RF beam transmitted by the antenna array.
11. The RF transmitter of claim 3 , wherein the plurality of antenna elements and the plurality of channels form an array/beamspace transformer configured to correlate a 2D beamspace array to a 1D beamspace array, each beamspace representing a set of resolvable beams of the transmitter in reciprocal space.
12. The RF transmitter of claim 11 ,
wherein the 1D beamspace array may be represented in real space by the N modulated optical signals at the first edge of the interference space.
13. The RF transmitter of claim 3 , wherein the first and second edges of the interference space respectively correspond to an input focal plane and an output focal plane of one or more lenses provided in the interference space.
14. The RF transmitter of claim 13 , wherein the one or more lenses comprises one or more cylindrical lenses.
15. The RF transmitter of claim 13 , wherein the interference space comprises free space.
16. The RF transmitter of claim 13 , wherein the interference space comprises a slab waveguide.
17. The RF transmitter of claim 13 , further comprising a filter that is positioned within the interference space, the filter being configured to isolate a sideband from each of the optical signals in the interference space.
18. The RF transmitter of claim 13 , further comprising an optical source configured to provide an optical carrier signal and a reference optical signal,
wherein the reference optical signal has a frequency offset from the optical carrier signal by a set amount and is phased locked with the optical carrier signal,
wherein the transmitter further comprises N electro optical modulators configured to modulate the optical carrier signal by a corresponding one of N data signals to generate the N modulated optical signals
wherein the RF transmitter further comprises one or more optical combiners to combine the reference optical signal with each of the optical signals of the channels to allow heterodyne detection of a corresponding RF signal represented with each of the optical signals.
19. The RF transmitter of claim 4 , wherein the plurality of channels, the interference space and the N optical waveguides form an optical processor, wherein the optical processor is interfaced with the antenna array to simultaneously emit N RF beams each having a carrier frequency within a frequency range of about 3 kHz-300 GHz.
20. The RF receive of claim 3 , wherein the channels comprise a lenslet/sensor array with lenslets of the lenslet/sensor array being arranged at the second edge of the interference space.
21. A method of RF signal processing, comprising:
providing an optical carrier signal of a first frequency and a reference optical signal of a second frequency, the first frequency and the second frequency differing by a set amount,
modulating the optical carrier signal with N data streams to form N modulated optical signals, where N is an integer greater than 1;
transmitting the N modulated optical signals as into an interference space at a first edge of the interference space with N optical waveguides arranged in a 1D array at the first edge, the N modulated optical signals respectively forming N optical beams in the interference space that are superimposed at a second edge of the interference space;
capturing the N optical beams as corresponding virtual beams within channels arranged in a 1D array at the second edge of the interference space;
converting optical signals of the channels to corresponding RF electrical signals; and
receiving the RF electrical signals with respective antenna elements of an antenna array to operate the respective antenna elements to thereby simultaneously emit N separate RF beams by the antenna array,
wherein each of the N modulated optical signals corresponds to an RF beam, and
wherein the location of the corresponding one of the N optical waveguides determines a propagation direction of the corresponding RF beam.