Conformal Optical Phased Array Feed Without Baluns
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Solution Overview
Problem
Conventional antenna arrays face challenges with balanced operation due to high input resistance in RF signal transmission, leading to imbalanced operation of radiating elements, and the use of baluns and other components restricts performance, particularly at high frequencies, increasing costs and complexity.
Innovation Solution
An optically fed antenna array system is developed, where optical fibers transmit signals to photodiodes, eliminating the need for baluns and other components by converting electrical signals to optical and back to electrical within the antenna array, allowing for a low-profile, conformal design with reduced physical space occupation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional 50-Ω coaxial line feeding is used to transmit RF signals to the antenna, then signal transmission is achieved, but balanced operation of the antenna elements deteriorates due to high input resistance
Solution Approach 1:
The patent replaces the conventional electrical RF signal transmission system (coaxial lines, baluns, impedance transformers) with an optical signal transmission system. Optical fibers carry modulated light signals to photodiodes that convert them back to electrical signals, eliminating the need for baluns and impedance matching components while achieving balanced antenna operation.
Solution Approach 2:
The patent introduces optical fibers and photodiodes as intermediary components between the signal source and the antenna elements. The optical fiber transmits the signal in the optical domain, and the photodiode converts it back to electrical form, serving as a mediator that avoids the problems of direct electrical transmission at high frequencies.
2Reliability
If baluns and impedance transformers are added to achieve balanced operation, then antenna balance is improved, but bandwidth and operational frequency performance deteriorate
Solution Approach 1:
The patent substitutes the frequency-sensitive electrical transmission system with an optical transmission system. Optical fibers have inherently wide bandwidth and are not subject to the frequency limitations and resonant behaviors that constrain baluns and impedance transformers, thereby expanding the operational frequency range and bandwidth of the antenna system.
3Reliability
If baluns and impedance transformers are incorporated into each radiating element, then balanced operation is achieved, but weight and profile increase
Solution Approach 1:
The patent replaces heavy electrical components (baluns, impedance transformers, coaxial cables) with lightweight optical components (optical fibers, photodiodes). Optical fibers are significantly lighter and more flexible, reducing the overall weight of the antenna array while maintaining signal transmission capability.
4Reliability
If conventional antenna array structures with baluns and RF transmission lines are used, then signal transmission is achieved, but installation complexity increases
Solution Approach 1:
The patent replaces the complex electrical interconnection system with an optical system. Optical fibers are more flexible and easier to route through confined spaces, and their connections are generally simpler and more robust than RF coaxial connections, reducing installation complexity.
5Volume of moving object
If optical fibers are used to feed the antenna array, then physical space occupation is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent merges the optical signal transmission function with the antenna feed system. By integrating photodiodes directly with the antenna elements and using optical fibers as the transmission medium, the system achieves a compact structure that reduces physical space occupation while the manufacturing complexity is managed through standard optical component integration techniques.
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
The optically fed antenna array achieves balanced operation without the need for baluns, enhancing bandwidth, frequency range, and reducing weight and cost, while maintaining high reliability and flexibility, particularly suitable for radar, data-links, communications, and imaging applications.
Implementation Method 1
Each optical fiber outputs its optical signal to a photodiode/antenna pair, where the photodiode receives the optical signal output from the optical fiber and outputs an electrical signal to drive the antenna
Implementation Method 2
transmitting signals are converted from the electrical domain to the optical domain by using electro-optic (EO) modulators
Data Source
AI summary
This disclosure is directed to two-dimensional conformal optically-fed phased arrays and methods for manufacturing the same. The method includes providing a wafer substrate, depositing a first cladding layer on the wafer substrate, and depositing a core layer on the first cladding layer. The method further includes photolithographically patterning the core layer to provide a plurality of optical waveguide cores, and depositing a second cladding layer on the core layer to cover the plurality of optical waveguide cores to provide a plurality of optical waveguides. In addition, the method includes forming a plurality of antennas on the second cladding layer, each antenna of the plurality of antennas located near a termination of a corresponding optical waveguide of the plurality of optical waveguides, and providing a plurality of photodiodes on the second cladding layer, each photodiode of the plurality of photodiodes connected to a corresponding antenna.