Conformal Optically Fed Phased Array Without Baluns or RF Feed Lines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional antenna arrays face challenges in achieving high-density, high-yield, and low-cost packaging of high-speed high-power photodiodes, particularly in optically driven phased arrays, due to imbalanced operation caused by high frequency RF signal transmission and the need for additional components like baluns and transformers, which affect bandwidth, operational frequency, weight, and cost.
Innovation Solution
A method of manufacturing an optically fed antenna array involving a wafer substrate with layered cladding and core materials, integrated optical waveguides, and photodiodes, where optical signals are converted to RF signals for balanced operation without the need for baluns or transformers, allowing for conformal and low-profile configurations.
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 the RF signal transmission is achieved, but the operation of the radiating elements becomes imbalanced and additional components (baluns, transformers) are required
Solution Approach 1:
The patent replaces the conventional electrical RF transmission system (coaxial lines, baluns, transformers) with an optical transmission system. Optical fibers deliver optical signals directly to photodiodes integrated with each antenna element, eliminating the need for electrical baluns and transformers while maintaining balanced operation. This substitution of the transmission medium fundamentally resolves the contradiction by removing the source of imbalance.
Solution Approach 2:
The patent introduces photodiodes as intermediary devices that convert optical signals to electrical signals at each antenna element. These photodiodes serve as local converters that directly drive the radiating elements in a balanced manner, eliminating the need for external baluns and transformers. The intermediary photodiodes enable balanced operation without adding the complexity of traditional RF transmission components.
2Reliability
If baluns and transformers are added to achieve balanced operation, then the operation balance is improved, but the bandwidth and operational frequency are restricted
Solution Approach 1:
By replacing the electrical RF transmission system with an optical transmission system, the patent eliminates the bandwidth limitations imposed by baluns and transformers. Optical fibers can transmit signals across extremely wide frequency ranges without the resonant frequency constraints of electrical transformers, thereby achieving both balanced operation and wide bandwidth simultaneously.
Solution Approach 2:
The patent changes the fundamental transmission parameter from electrical frequency to optical frequency. This parameter change allows the system to operate over a much broader effective bandwidth, as optical carriers can be modulated across wide frequency ranges without the restrictive impedance matching and resonant frequency requirements that limit electrical baluns and transformers.
3Reliability
If baluns, amplifiers and RF transmission lines are used, then the RF signal transmission is achieved, but the weight and profile of the antenna array increase
Solution Approach 1:
The patent replaces heavy electrical RF transmission infrastructure (coaxial cables, amplifiers, baluns) with lightweight optical fibers and integrated photodiodes. Optical fibers have significantly lower weight and smaller physical dimensions compared to electrical RF transmission lines, directly reducing the overall weight and profile of the antenna array while maintaining effective signal transmission.
4Reliability
If conventional antenna array structures are used, then the RF signal transmission is achieved, but the conformability to non-planar surfaces is limited
Solution Approach 1:
The patent employs flexible optical waveguides and thin-film photodiode structures that can be conformally integrated onto non-planar surfaces. These flexible optical components can bend and adapt to curved surfaces without compromising signal transmission, enabling the antenna array to be mounted on aerodynamic surfaces, curved substrates, or non-planar platforms while maintaining RF performance.
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 solution enables efficient conversion of optical signals to RF signals, reducing physical space and cost while maintaining balanced operation, facilitating conformal integration on non-planar surfaces with reduced complexity and improved performance.
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 to which it is connected
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 substrate, depositing a first cladding layer on the 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.