VLF Scatterer Array for Ocean Surface Signal Control
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Solution Overview
Problem
Conventional VLF transmitters are large and costly, relying on massive size and ionospheric propagation, making them difficult to control and intercept-resistant, with limited ability to manage signal coverage.
Innovation Solution
A distributed array of electrically small scatterers on autonomous platforms coupled to electrically small transmitters, using tunable or static reactance elements to control VLF signal propagation and minimize radiation outside the desired area, allowing for precise control of signal coverage without increasing transmitter power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional large monolithic VLF transmitters are used, then VLF signal coverage over large areas is achieved, but transmitter size and power requirements become massive
Solution Approach 1:
The patent divides the conventional monolithic VLF transmitter into multiple distributed scatterers arranged in an array. Each scatterer is electrically small and can be independently controlled, allowing the system to achieve large coverage area without requiring a single massive transmitter structure
Solution Approach 2:
The patent introduces an array of scatterers as intermediary elements between the VLF transmitter and the propagation medium. These scatterers modify the electromagnetic field distribution to extend coverage area while keeping individual transmitter components small
2Area of stationary object
If conventional VLF transmitters rely on ionospheric propagation, then signals are broadcast over extremely large areas, but signal interception becomes easier
Solution Approach 1:
The patent applies local quality by configuring the scatterer array to create localized field enhancement in specific directions while suppressing radiation in others. This allows concentrated signal delivery to target areas rather than omnidirectional broadcast, reducing interception opportunities
Solution Approach 2:
The patent employs dynamic control of the scatterer array through phased array techniques, allowing real-time adjustment of signal direction and coverage area. This dynamic steering capability enables precise signal confinement to intended receivers, minimizing exposure to potential interceptors
3Power
If conventional VLF transmitters use massive structures, then efficient VLF transmission is achieved, but control of signal coverage is limited
Solution Approach 1:
The patent implements dynamic control through independent phase and amplitude adjustment of each scatterer element. This allows the system to adaptively shape the radiation pattern, steer beams, and control coverage area in real-time while maintaining transmission efficiency
Solution Approach 2:
The patent utilizes parameter changes by varying the phase and amplitude of signals fed to each scatterer. These parameter adjustments enable flexible control of signal coverage characteristics without compromising the fundamental transmission efficiency of the VLF system
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
Enables extended VLF signal coverage over a contained area without massive transmitters or power, reducing signal interception risks and improving directional control of radiation.
Implementation Method 1
control of electromagnetic wave propagation on the ocean surface
Implementation Method 2
Each scatterer in the array preferably comprises an electrically small antenna, in a preferred embodiment this antenna is a small monopole although any variety of electrically small antennas could be used, such as electrically small loop antennas. The reactive tuning elements may comprise tunable capacitors and inductors
Data Source
AI summary
An array of preferably electrically small scatterers is spaced at more or less regular intervals from a central transmitter. Each scatterer element includes a tunable or static reactive load which allows the propagation and fields generated by the central transmitter to be precisely controlled. Each scatterer element in the array also includes a resistive element whose value may change as a function of a distance between each scatterer and the central transmitter and which typically increases as a function of that distance. The central transmitter in the array nominally comprises an antenna, matching network, RF driver, and a vehicle, which may be a maritime vehicle or platform. The antenna for this transmitter may be comprised of an electrically small monopole oriented normal to the surface of the ocean or an electrically small loop antenna oriented with its magnetic moment parallel to the surface of the ocean.