Optically Driven Plasma Antenna for Inactive State Transparency
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Solution Overview
Problem
Existing plasma antennas remain electrically visible when inactive, leading to scattering, reflecting signatures, and interference with nearby antennas, as they do not have a mechanism to be turned off and rendered invisible.
Innovation Solution
An optically driven, geometrically reconfigurable plasma antenna that uses a laser or light emitting diode to impinge on a passive semiconductor wafer, creating a microwave reflector with a spatially and temporally defined plasma area, which becomes transparent to microwaves when the light source is turned off, allowing the antenna to be electrically invisible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a plasma antenna is used for wireless signaling, then antenna functionality is achieved, but the antenna remains electrically visible when inactive, causing scattering and reflecting signatures
Solution Approach 1:
The patent applies dynamics by making the antenna structure dynamically controllable through optical injection. The plasma density in the semiconductor wafer can be dynamically adjusted by controlling the intensity and duration of light injection, allowing the antenna to transition between active and invisible states. This dynamic control enables the antenna to adapt its electrical properties based on operational requirements.
Solution Approach 2:
The patent changes the physical parameter of plasma density through optical injection to control antenna visibility. By varying the carrier concentration in the semiconductor material using light, the antenna's electrical properties are fundamentally altered. When inactive, the plasma density is reduced to levels that make the antenna electrically invisible, thereby eliminating scattering and reflecting signatures while maintaining structural integrity.
2Reliability
If a plasma antenna is used for wireless signaling, then transmitting and receiving capability is achieved, but interference and coupling with other nearby antennas occurs when inactive
Solution Approach 1:
The patent enables dynamic control of antenna interference characteristics through optical injection timing and duration. When the antenna is inactive, the optical injection is reduced or stopped, causing plasma density to decay and the antenna to become electrically invisible. This dynamic state change prevents coupling and interference with other nearby antennas while preserving full transmitting and receiving capability when active.
3Use of energy by moving object
If a reflecting surface is added behind the photoconducting wafer to enable low light intensity operation, then antenna generation at low light intensities is achieved, but the antenna remains electrically visible due to constant presence of conducting reflector
Solution Approach 1:
The patent extracts or removes the permanent conducting reflector from the antenna structure and replaces it with a transient plasma reflector created through optical injection. The plasma in the semiconductor wafer itself provides the necessary reflection capability temporarily during active operation, then disappears when injection stops. This eliminates the constant electrical visibility problem caused by permanent reflectors while maintaining low light intensity operation benefits.
Solution Approach 2:
The patent changes the reflector's physical state from permanent conducting material to transient plasma. By controlling optical injection parameters, the plasma density is adjusted to provide sufficient reflection during active operation, then naturally decays to invisible levels when inactive. This parameter control allows the same structure to serve both as low-light enabler and visibility controller.
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 effectively reduces scattering and interference by becoming electrically invisible when inactive, minimizing coupling with other antennas through its ability to change reflectivity based on light exposure.
Implementation Method 1
A laser or light emitting diode (LED) fed, geometrically reconfigurable plasma or electron hole concentration antenna
Implementation Method 2
A highly ionized plasma is essentially a good conductor, and therefore plasmas can serve as transmission line elements for guiding waves, or antenna surfaces for radiation
Data Source
AI summary
There is provided an optically driven, transmitting and receiving antenna transformable into an electrically invisible antenna when inactive, including a light source, a semiconductor wafer illuminatable by the light source and a microwave source or sensor. The wafer has a surface for forming optically induced plasma or electron hole concentration, assuming a spatial and temporal pattern defined by a light beam impinging thereon. Upon the wafer being exposed to the light beam having a power level sufficient for creating a dense plasma or electron hole concentration in the wafer, the wafer becomes reflective to microwaves, and returns to transparency when light from the light source is turned off.