Dual-Taper Spoof Plasmon Waveguide for Permittivity Sensing
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Solution Overview
Problem
Existing plasmonic sensors face challenges in detecting small permittivity changes associated with analytes in the electromagnetic frequency range, particularly for gas and fluid sensing, due to weak dependence on phase composition, and require improved sensitivity and compatibility with low-cost production methods.
Innovation Solution
A spoof plasmonic sensor with a waveguide featuring dual-tapered spoof plasmon cavities on a substrate that changes permittivity upon contact with an analyte, allowing for detection through electromagnetic signal modification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional plasmonic sensors are used for gas and fluid sensing, then the sensing mechanism is established, but the sensitivity is insufficient due to weak dependence on phase composition and small permittivity changes
Solution Approach 1:
The patent transforms the sensing mechanism from direct detection of small permittivity changes to detection of large temperature changes induced by phase transitions. When the substrate material undergoes phase transition (e.g., from crystalline to amorphous state), its permittivity changes dramatically (from ~2.5 to ~4.0), providing a strong sensing signal that overcomes the weakness of detecting small permittivity changes in conventional plasmonic sensors.
Solution Approach 2:
The patent directly utilizes phase transitions of the substrate material as the sensing mechanism. The substrate is designed to undergo phase transition at specific temperatures, causing abrupt changes in its electromagnetic properties. This allows the sensor to detect temperature changes through the phase transition phenomenon, achieving high sensitivity in the microwave frequency range where conventional sensors struggle.
2Measurement precision
If photonic plasmonic devices are used, then high sensing precision is achieved, but the device dimensions are extremely small (∼100 nm) making fabrication complex and costly
Solution Approach 1:
The patent transitions from photonic scale (nanometer dimension) to microwave scale (millimeter/centimeter dimension) by changing the operating frequency dimension. The spoof plasmon waveguide structures have periodic grooves with spacings on the order of millimeters rather than nanometers, allowing the same plasmonic sensing mechanism to operate at microwave frequencies where the device dimensions are thousands of times larger, enabling standard fabrication techniques to be used.
Solution Approach 2:
The patent replaces the optical field (photonic) with microwave electromagnetic field. By operating in the microwave frequency range instead of optical frequencies, the device dimensions scale up from nanometer to millimeter scale, allowing conventional PCB fabrication and metal deposition techniques to be used instead of complex nanofabrication processes required for photonic devices.
3Adaptability or versatility
If periodic grooves are used to extend plasmonic sensing to microwave range, then the application range is expanded, but the device dimensions increase making integration with external antennas more challenging
Solution Approach 1:
The patent merges the spoof plasmon waveguide structure with the substrate material itself, creating an integrated sensing platform. The periodic grooves are etched directly into the substrate, and the substrate material serves dual purposes as both the structural support and the phase-transitioning sensing element. This integration eliminates the need for separate antenna components and simplifies the overall device architecture, making it easier to fabricate and deploy.
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 sensor provides nearly instantaneous detection of analytes with high sensitivity, capable of detecting permittivity changes down to 0.1% and operating in the 1-100 GHz frequency range, suitable for gas and fluid sensing with ease of manufacturing.
Implementation Method 1
a substrate with a superior surface; and a conductive material disposed on the superior surface, wherein the conductive material defines a waveguide, wherein the waveguide defines spoof plasmon cavities comprising the substrate, and wherein the substrate is configured to change in permittivity when contacted by an analyte
Implementation Method 2
electric fields have increased localization in the substrate region which serves to improve sensing response to substrate permittivity changes
Implementation Method 3
periodic grooves, in effect, create a planar metamaterial surface whose properties are determined by effective permittivity and permeability parameters
Data Source
AI summary
A method to detect the presence and or concentration of an analyte in the environment of a spoof plasmon sensor having the steps of: providing a spoof plasmon sensor into an environment; interrogating said spoof plasmon sensor with an electromagnetic signal; collecting a modified electromagnetic signal from the spoof plasmon sensor; and analyzing the modified electromagnetic signal to detect an analyte in the environment of the sensor. A spoof plasmon sensor for detecting an analyte having a substrate with a superior surface; and a conductive material disposed on said superior surface, said conductive material defining a waveguide having a dual tapering shape, wherein said waveguide defines spoof plasmon cavities which are exposed substrate, where said substrate is configured to change in permittivity when contacted by an analyte.