Segmentally Time-Variant Antenna for VLF Transmission
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Solution Overview
Problem
Existing electrically short antennas face limitations in efficiently transmitting Very Low Frequency (VLF) waves due to high impedance and reflection issues, which restricts broadband VLF generation and usage in applications like global navigation and underground sensing.
Innovation Solution
A segmentally time-variant antenna with individually controllable segments, such as an ionized plasma antenna, where conductivity is modulated to allow pulses to propagate one-way, preventing reflections and enhancing efficiency by dynamically controlling the flow of current and charge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional electrically short antennas are used for VLF transmission, then the antenna size can be kept small, but the radiation efficiency deteriorates due to high impedance and reflection issues
Solution Approach 1:
The patent applies plasma as a dynamically controllable medium where conductivity can be rapidly switched between ionized (conductive) and non-ionized (insulating) states. This dynamic property allows the antenna to efficiently radiate during transmission while maintaining a compact form factor, resolving the contradiction between small size and radiation efficiency.
Solution Approach 2:
The patent changes the electrical parameters of the antenna medium by ionizing plasma to achieve high conductivity during transmission, then de-ionizing to reduce losses when not in use. This parameter change enables efficient broadband VLF transmission from electrically short structures without the traditional efficiency penalties.
2Adaptability or versatility
If broadband VLF transmission is achieved using traditional antennas, then the bandwidth can be increased, but the antenna length must be increased to accommodate the wavelength requirements
Solution Approach 1:
The time-variant conductivity of plasma segments allows broadband signal transmission from electrically short structures. By dynamically controlling which plasma segments are ionized during different phases of the broadband signal, the antenna achieves broadband performance without requiring physical lengths comparable to the wavelengths being transmitted.
Solution Approach 2:
The patent divides the plasma antenna into multiple independently controllable segments. Each segment can be ionized at different times, enabling broadband signal transmission through constructive interference of multiple frequency components while maintaining a compact overall structure.
3Productivity
If plasma conductivity is rapidly modulated to prevent pulse reflection, then the transmission efficiency is improved, but the device complexity increases due to multiple controllable segments
Solution Approach 1:
The patent uses periodic modulation of plasma segment conductivity synchronized with the transmitted pulse timing. This periodic switching pattern, where segments are ionized in sequence as the pulse propagates, efficiently prevents reflections and maintains forward wave propagation without requiring complex real-time control algorithms.
Solution Approach 2:
The system incorporates timing feedback based on the known pulse propagation velocity through plasma. The segment controller uses this feedback to precisely time the ionization and de-ionization of each segment, ensuring optimal reflection prevention while maintaining manageable system complexity through deterministic control.
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 enables efficient broadband transmission of VLF waves, overcoming the limitations of traditional antennas by maintaining high efficiency and small size without sacrificing bandwidth, and is applicable across various frequency ranges.
Implementation Method 1
The ionized plasma antenna can comprise electrodes corresponding to the individual segments of the plurality of segments, the electrodes energized and de-energized by the segment controller to modulate the conductivity of plasma in the individual segments
Data Source
AI summary
Various methods, apparatus, devices and systems are provided for electrically short antennas for efficient broadband transmission. In one example, among others, a system includes a segmentally time-variant antenna and a segment controller that can control conductivity of individual segments of the segmentally time-variant antenna. The conductivity of the individual segments is modulated to allow a pulse to propagate from the proximal end to the distal end of the segmentally time-variant antenna and impede a reflection of the pulse from propagating back to the proximal end of the segmentally time-variant antenna. In another embodiment, a method includes injecting a pulse at a first end of a segmentally time-variant antenna and modulating conductivity of individual segments to allow the pulse to propagate to a second end of the segmentally time-variant antenna and impede a reflection of the pulse from propagating back to the first end.