# US 2021/0242941 A1 · Distributed array for direction and frequency finding

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- Number: US 2021/0242941 A1
- Document ID: US20210242941A1
- Status: Published application
- Kind: A1
- Application number: 17/151,565
- Filed: 2021-01-18
- Published: 2021-08-05
- Earliest claimed: 2015-08-03
- Assignees: Phase Sensitive Innovations, Inc.
- Applicants: Phase Sensitive Innovations, Inc.
- Inventors: Janusz Murakowski; Christopher Schuetz; Garrett Schneider; Shouyuan Shi
- Web page: https://patentgrep.com/patent/US20210242941A1

## CPC

- H04B 10/2575: Radio-over-fibre, e.g. radio frequency signal modulated onto an optical carrier
- H04B 10/00: Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B 10/69: Electrical arrangements in the receiver
- H04B 2210/006: Devices for generating or processing an RF signal by optical means
- H04B: TRANSMISSION

## Abstract

An optical imaging system and method that reconstructs RF sources in k-space by utilizing interference amongst modulated optical beams. In some examples, the system and method may record the interference pattern produced by RF-modulated optical beams conveyed by optical fibers having unequal lengths. The photodetectors record the interference, and computational analysis using known tomography reconstruction methods is performed to reconstruct the RF sources in k-space.

## Claims

### Claim 1

An optical imaging receiver comprising:
a phased-array antenna including a plurality of antenna elements arranged in a first pattern configured to receive RF signals from at least one RF source;
a plurality of electro-optic modulators corresponding to the plurality of antenna elements, each modulator configured to modulate an optical carrier with a received RF signal to generate a plurality of modulated optical signals;
a plurality of optical channels configured to carry the plurality of modulated optical signals and configured to cause interference amongst the optical signals, each of the plurality of optical channels having an output to emanate the corresponding modulated optical signal out of the corresponding optical channel, the outputs of the plurality of optical channels arranged in a second pattern which does not correspond to the first pattern;
a plurality of photodetectors for recording the optical signal interference; and
a module for computationally reconstructing RF sources in k-space from the recorded interference.