Lens-Coupled Fiber Array Receiver for Optical RF Angle Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional RF receivers are limited by dynamic range due to spurious intermixing of signals and jamming, which leads to reduced ability to distinguish genuine signals from unwanted products, and require cumbersome computations for determining the angle of arrival of RF signals.
Innovation Solution
The implementation of a wideband RF phased-array receiver that upconverts RF signals to the optical domain using electro-optic modulators, allowing for spatial separation of signal sources before detection, thereby reducing nonlinear signal mixing and enhancing dynamic range and resistance to jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RF receivers process signals in the RF domain, then the receiver structure is simple, but the dynamic range is limited due to spurious intermixing of signals and jamming
Solution Approach 1:
The patent replaces the conventional RF-domain signal processing system with an optical-domain system. RF signals are converted to optical signals through electro-optic modulation, allowing signals to be processed in the optical domain rather than the RF domain. This substitution eliminates spurious intermixing and jamming issues that limit dynamic range in conventional RF receivers, while the optical processing architecture provides the necessary functionality for signal separation and angle of arrival determination.
Solution Approach 2:
The patent introduces an optical intermediary system consisting of electro-optic modulators, optical waveguides, and optical detectors. These components act as intermediaries that convert RF signals to optical signals, transmit them through optical waveguides with spatially separated paths, and detect them at the output. This intermediary optical system enables signals from different spatial locations to be processed independently, improving dynamic range by preventing signal intermixing.
2Measurement precision
If conventional RF receivers determine angle of arrival using computations, then the receiver is simple, but the process is cumbersome and time-consuming
Solution Approach 1:
The patent performs preliminary spatial separation of signals in the optical domain before detection. Optical waveguides are arranged to spatially separate signals originating from different directions, and optical phase shifts are applied in advance to steer signals to appropriate detectors. This preliminary spatial and phase processing eliminates the need for complex post-detection computations to determine angle of arrival, providing real-time measurement without time-consuming calculations.
Solution Approach 2:
The patent transitions from RF-domain signal processing to optical-domain processing, adding a spatial dimension to signal separation. Optical waveguides are positioned at different locations and orientations to create spatially distinct signal paths. This dimensional approach allows angle of arrival to be determined by the spatial distribution of optical signals at the detector array, replacing computational methods with direct spatial measurement.
3Reliability
If RF signals are upconverted to optical domain using electro-optic modulators, then dynamic range improves, but device complexity increases
Solution Approach 1:
The patent segments the optical processing system into distinct functional modules: electro-optic modulators for RF-to-optical conversion, optical waveguides for signal transmission and spatial separation, optical phase shifters for beam steering, and optical detectors for signal detection. Each module performs a specific function and can be independently optimized or replaced. This segmentation manages complexity by organizing the optical processing architecture into manageable, functionally-separated components.
Solution Approach 2:
The patent employs universal optical components that can handle multiple signal channels simultaneously. A single optical waveguide array can process multiple RF signals from different antenna elements, and a single detector array can detect multiple optical signals. The electro-optic modulators and optical phase shifters are configured to operate across broad frequency ranges, providing multi-functional capability that reduces the need for separate components for each signal channel, thereby managing overall system complexity.
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 signals in the optical domain, enabling real-time determination of signal angle of arrival and simultaneous processing of multiple RF signals across a broad frequency range.
Implementation Method 1
The plurality of electro-optic modulators may also be configured to generate a corresponding upconverted optical signal by mixing the corresponding RF signal with an optical carrier beam
Implementation Method 2
a first bundle of optical waveguides, each optical waveguide may have an end and be in communication with a corresponding one of the plurality of electro-optic modulators to receive and transmit a respective upconverted optical signal
Implementation Method 3
an interference space to receive the plurality of upconverted optical signals transmitted by the first bundle of optical fibers to form a composite beam
Implementation Method 4
a sensor array comprising a plurality of sensors arranged in a detection plane that is in optical communication with the interference space to receive the composite beam. Additionally, each of the sensors of the sensor array may be positioned to receive a respective portion of the composite beam impinged thereon
Data Source
AI summary
An RF receiver may include antenna elements to receive RF signals, and electro-optic modulators to generate corresponding upconverted optical signals by mixing an RF signal with an optical carrier beam. The RF receiver may include a transmission array having a first bundle of optical waveguides that receive and transmit upconverted optical signals from their ends. The ends may be arranged in a first pattern. The RF receiver may include an interference space to receive the upconverted optical signals to form a composite beam, and an array of single mode optical fibers that have lenses positioned in a detection plane to receive a portion of the composite beam. The first pattern of the ends generates an RF emitter interference pattern at the detection plane, and the single mode optical fiber lenses have a geometric arrangement that corresponds to the first RF emitter interference pattern.