Phased-Array RF Receiver Using Optical Processing Against Jamming
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Solution Overview
Problem
Conventional RF receivers are limited in dynamic range by spurious intermixing of signals and/or jamming, which cannot be distinguished from genuine signals, leading to reduced performance and increased latency.
Innovation Solution
The RF signals are upconverted by fiber-coupled optical phase modulators driven by a phased-array antenna, generating optical sidebands that preserve phase and amplitude information, allowing spatial separation of signal sources before electrical detection, enhancing dynamic range and resistance to jamming through optical processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RF receivers process signals directly in the electrical domain, then the device complexity is low, but the dynamic range is limited due to spurious intermixing of signals and jamming
Solution Approach 1:
The patent replaces the conventional electrical domain signal processing system with an optical domain system. RF signals are converted to optical signals using electro-optic modulators, processed in the optical domain, and then converted back to electrical signals for detection. This substitution enables spatial separation of signal sources through optical processing, thereby improving dynamic range and resistance to jamming while maintaining manageable device complexity through modular architecture.
2Measurement precision
If RF signals are processed in the electrical domain, then the processing speed is high, but spurious intermixing occurs reducing measurement precision
Solution Approach 1:
The patent introduces an optical domain as an intermediary between RF signal reception and electrical domain detection. RF signals are first converted to optical signals, which serve as intermediaries that can be spatially separated and processed without the spurious intermixing problems of direct electrical processing. This intermediary approach maintains processing speed while significantly improving measurement precision through optical spatial filtering and signal separation techniques.
3Reliability
If optical processing is used to separate signal sources spatially, then the dynamic range improves, but the device complexity increases due to additional optical components
Solution Approach 1:
The patent segments the signal processing function into distinct modules: RF antenna array, electro-optic modulators, optical processing elements, and photodetector array. Each segment performs a specific function and can be independently optimized. This segmentation allows the system to achieve high dynamic range and jamming resistance through optical spatial separation while managing device complexity through modular, scalable architecture where each component is relatively simple but collectively provides sophisticated signal processing capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the dynamic range and tolerance to jamming by processing RF signals in the optical domain, enabling real-time angle of arrival determination and effective suppression of unwanted signals, thus improving receiver performance.
Implementation Method 1
a phased-array antenna that include a plurality of antenna elements and a corresponding plurality of electro-optic modulators. The antenna elements are arranged in a first pattern and configured to receive RF signals from at least one source
Implementation Method 2
The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals
Implementation Method 3
Each of the optical channels has an output, and the plurality of channel outputs is arranged in a second pattern that corresponds to the pattern of the antenna elements
Implementation Method 4
A detector, for example a photodiode, may be configured to receive at least a portion of the composite optical signal and to extract non-spatial information from a received RF signal
Data Source
AI summary
A method of RF signal processing comprises receiving an incoming RF signal at each of a plurality of antenna elements that are arranged in a first pattern. The received RF signals from each of the plurality of antenna elements are modulated onto an optical carrier to generate a plurality of modulated signals that each have at least one sideband. The modulated signals are directed along a corresponding plurality of optical channels with outputs arranged in a second pattern corresponding to the first pattern. A composite optical signal is formed using light emanating from the outputs of the plurality of optical channels. Non-spatial information contained in at least one of the received RF signals is extracted from the composite signal.