Patch Antenna Temperature Measurement via Dielectric Resonance
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Solution Overview
Problem
Existing temperature measurement techniques, such as thermocouples, face challenges in high-temperature environments like gas turbine engines due to reliability issues and space constraints, and existing antenna-based methods do not effectively account for significant dielectric constant changes with temperature.
Innovation Solution
A method using a patch antenna with a dielectric substrate to measure temperature by analyzing the change in dielectric constant through microwave electronics, where a network analyzer sends electromagnetic signals and measures reflection coefficients to calculate the antenna's center frequency, which is then mapped to temperature using a calibration curve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouples or other temperature measurement devices are embedded within the antenna, then temperature measurement capability is improved, but device complexity and space requirements increase
Solution Approach 1:
The antenna structure is designed to serve dual functions: both as an electromagnetic radiating element and as a temperature sensor. The dielectric substrate material experiences temperature-induced changes in its dielectric constant, which directly affect the antenna's resonant frequency. By monitoring the antenna's operating frequency, temperature information is obtained without requiring separate measurement devices, thus eliminating additional wiring and reducing overall device complexity.
Solution Approach 2:
The antenna itself performs the temperature measurement function by utilizing the temperature dependence of its dielectric substrate's dielectric constant. The structure essentially measures its own temperature through the frequency shift caused by thermal effects on the dielectric material, eliminating the need for external thermocouples or separate sensing elements that would require additional installation complexity.
2Reliability
If active cooling is used to maintain antenna operating temperature, then antenna functionality is improved, but device complexity and cooling system requirements increase
Solution Approach 1:
Instead of attempting to maintain the antenna at a constant operating temperature through active cooling, the invention embraces the high temperature environment by designing the antenna with a dielectric substrate specifically selected for its stability and performance at elevated temperatures. The measurement technique compensates for temperature effects by monitoring frequency shifts, allowing the antenna to function reliably without complex cooling systems. The dielectric material is chosen to withstand the thermal environment while providing measurable frequency-temperature characteristics.
3Ease of manufacture
If the dielectric constant change with temperature is not accounted for, then antenna design is simplified, but measurement precision deteriorates
Solution Approach 1:
The system incorporates a feedback mechanism where the antenna's operating frequency is continuously monitored and used to determine the dielectric constant of the substrate material. By tracking frequency shifts that result from temperature-induced dielectric constant changes, the system accurately determines temperature. This feedback approach maintains design simplicity while achieving high measurement precision, as the frequency measurement directly provides temperature information through the known frequency-dielectric constant relationship.
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 allows for accurate temperature measurement in high-temperature environments without the need for additional wiring or complex embedding, leveraging the existing antenna structure and materials that withstand extreme temperatures.
Implementation Method 1
All dielectric materials exhibit some change in dielectric constant as a function of temperature
Implementation Method 2
The center frequency of a patch antenna is based on a designed resonance frequency that is a function of the metallization geometry as well as the dielectric constant
Implementation Method 3
Antennas are used to transmit and receive electromagnetic energy
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
A temperature measurement technique for calculating a temperature in a high temperature environment by monitoring a change in resonant frequency of a resonant structure loaded with a dielectric material. A response curve for a reflection coefficient S11 associated with the resonant structure is generated, typically by the use of a network analyzer connected to the resonant structure via a cable. A minimum point for the response curve is identified to detect the resonant frequency for the resonant structure. A calibration map is applied to the minimum point to identify a temperature associated with the resonant frequency of the resonant structure. The temperature associated with the resonant frequency of the resonant structure represents the temperature of the high temperature environment.