Closed-Loop Polarized ULF/VLF Antenna With Segmented Ferrite Core
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Solution Overview
Problem
Existing transceiver antennas for transmitting signals with wavelengths larger than the radiation wavelength are inefficient and lack polarization discrimination, with ferrite rod arrays experiencing cross-talk issues and efficiency drops with decreasing length-to-diameter ratios.
Innovation Solution
A transmission antenna with a closed-loop core and two electrically-conductive windings that generate opposing magnetic fluxes, allowing for polarized signal transmission with a flat frequency response and minimal cross-talk, enabling broadband transmission and independent control of multiple polarized signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If ferrite rod arrays are used to increase efficiency at lower frequencies, then transmission efficiency is improved, but cross-talk between individual ferrite rods limits the ability to control polarization and directionality
Solution Approach 1:
The antenna divides the ferrite core into multiple discrete segments (first ferrite rod segment, second ferrite rod segment, third ferrite rod segment) with windings on specific segments. This segmentation allows independent control of magnetic flux in different regions, enabling polarization control while maintaining efficiency.
Solution Approach 2:
Different segments of the ferrite core have different winding configurations (e.g., first winding on first segment, second winding on second segment). This creates local variations in magnetic properties that enable directional control and polarization discrimination while maintaining overall system efficiency.
2Volume of moving object
If the length to diameter ratio of ferrite rod is decreased, then the antenna becomes more compact, but the efficiency of the ferrite rod drops dramatically
Solution Approach 1:
The ferrite core is segmented into multiple rods with windings on specific segments rather than requiring a single long rod. This allows the antenna to achieve compact dimensions while maintaining efficient magnetic coupling through the segmented structure.
Solution Approach 2:
Multiple ferrite rod segments are combined into a unified core structure with coordinated windings. The segments work together to maintain magnetic flux efficiency while allowing a more compact overall antenna design compared to a single long rod.
3Adaptability or versatility
If conventional antennas are used for broadband transmission, then frequency coverage is improved, but polarization discrimination is not provided
Solution Approach 1:
Different windings are placed on different segments of the ferrite core with specific orientations. This creates localized magnetic field regions with different polarization characteristics, enabling polarization discrimination while maintaining broadband operation through the distributed structure.
Solution Approach 2:
The winding configurations on different ferrite segments are asymmetrically arranged to produce distinct polarization states. This asymmetry enables polarization control and discrimination while the distributed segmented structure supports broadband frequency operation.
4Adaptability or versatility
If multiple windings are added to provide multiple polarized signals, then signal versatility is improved, but device complexity increases
Solution Approach 1:
Multiple windings are combined on a shared segmented ferrite core structure rather than using separate antenna elements. This merging approach enables multiple polarized signals to be generated from a single integrated device, reducing overall complexity while maintaining versatility.
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 antenna achieves high-efficiency, nearly frequency-independent transmission of polarized signals with strong polarization within the closed-loop plane, suitable for applications like ground penetrating radar and misaligned-beam radar, with minimal cross-talk between windings.
Implementation Method 1
The first winding has an electrically-conductive wire transversely wound around a first segment of the closed-loop core, and is configured for generating a magnetic flux in a first direction along the closed-loop core when electrical current passes through the first winding
Data Source
AI summary
A transmission antenna includes a closed-loop core having at least two electrically-conductive windings arranged on the closed-loop core. The windings are each electrically-actuated to generate a magnetic flux along the closed-loop core in opposing directions. The transmission antenna may generate a polarized magnetic field within a plane of the closed-loop core and provide broadband transmission of a polarized signal having a relatively flat frequency response. The transmission antenna is electrically-small, and the frequency of the polarized signal is nearly independent of the size of the closed-loop core. Multiple polarized signals may be provided, each being independently and continuously controlled through actuation of the windings. The direction of the polarized signal may also be varied. Additional windings for receiving a signal may simultaneously be employed on the closed-loop core. A method for transmitting a polarized signal with the transmission antenna is also provided.