Wireless High Temperature Sensing Chipless Tag Based on a Diamond Ring Resonator

At a Glance

Metadata	Details
Publication Date	2023-03-25
Journal	Micromachines
Authors	Bo Wang, Youwei Li, Tingting Gu, Ke Wang
Institutions	Xi’an University of Posts and Telecommunications
Citations	3
Analysis	Full AI Review Included

Executive Summary

This research details the design and simulation of a passive, wireless, chipless temperature sensor tag optimized for extreme high-temperature environments.

Core Value Proposition: Provides real-time, passive temperature monitoring (200 °C to 1000 °C) in harsh environments where traditional sensors (thermocouples, thermal imagers) fail or require power.
Structure and Materials: The sensor utilizes a double diamond split ring resonator (SRR) structure, printed using Platinum metal on an Alumina ceramic (Al₂O₃) substrate.
Sensing Principle: Temperature change alters the permittivity (dielectric constant, ε_r) of the Alumina substrate. This change shifts the sensor’s resonant frequency (f), allowing temperature to be measured remotely via frequency monitoring.
Performance Metrics: Achieved a wide operating range (800 °C span) with a high average sensitivity of 0.375 MHz/°C, significantly outperforming many existing ceramic-based sensors.
Miniaturization: The sensor features a compact size of 23 x 23 x 0.5 mm³, making it suitable for integration into small components.
Frequency Response: The resonant frequency (f) is inversely proportional to temperature (T). As T rises from 200 °C to 1000 °C, the frequency shifts monotonically downward by 300 MHz (from 6.79 GHz to 6.49 GHz).

Technical Specifications

Parameter	Value	Unit	Context
Overall Sensor Size	23 x 23 x 0.5	mm³	Miniaturized design dimensions.
Operating Temperature Range	200 to 1000	°C	Wide range for high-temperature monitoring.
Total Frequency Shift	300	MHz	Shift observed across the 800 °C range (6.79 GHz to 6.49 GHz).
Average Sensitivity (S)	0.375	MHz/°C	Relative sensitivity across the full operating range.
Maximum Sensitivity (S)	0.6	MHz/°C	Sensitivity observed at the lower end of the temperature range.
Substrate/Sensing Material	Alumina Ceramic (Al₂O₃)	N/A	Selected for high thermal resistance (sintered near 2000 °C).
Resonator Material	Platinum (Pt)	N/A	Printed metal structure.
Dielectric Constant Range (ε_r)	9.8 to 11.0	N/A	Corresponds to 200 °C to 1000 °C.
Inner Ring Split (b)	0.34	mm	Key design parameter for resonant frequency tuning.
Outer Ring Split (a)	4.14	mm	Key design parameter for resonant frequency tuning.
Fabrication Method	Screen Printing	N/A	Simple, low-cost manufacturing process.

Key Methodologies

The sensor design and characterization relied heavily on electromagnetic simulation and material property analysis:

Structural Design: A double diamond split ring resonator (SRR) structure was selected for its good Radar Cross Section (RCS) frequency response, high Q value, and simple, symmetrical design, allowing for easy adjustment of equivalent capacitance and inductance.
Material Selection: Alumina ceramic was chosen as the substrate due to its high thermal conductivity, mechanical strength, and inherent temperature-dependent dielectric constant (ε_r).
Fabrication Method: The Platinum resonator structure was designed to be applied to the Alumina substrate surface using low-cost, simple screen printing technology.
Simulation Environment: The High-Frequency Structure Simulator (HFSS) software was used to model the passive wireless sensor system.
Boundary Conditions: Simulation boundaries were defined using Perfect Electrical Conductor (PEC) planes (perpendicular to the y-axis) and Perfect Magnetic Conductor (PMC) planes (perpendicular to the x-axis).
Temperature Simulation: The effect of temperature (T) was simulated by monotonically increasing the substrate’s dielectric constant (ε_r) from 9.8 (200 °C) to 11.0 (1000 °C).
Response Characterization: The simulation confirmed the inverse relationship: T increases → ε_r increases → resonant frequency (f) decreases. This relationship was quantified and fitted into two quasi-linear equations for practical temperature extraction.

Commercial Applications

This passive, high-temperature sensing technology is critical for industries requiring non-contact, real-time condition monitoring in extreme heat:

Aerospace and Aviation: Real-time monitoring of turbine engine blades, combustion chambers, and high-speed components to prevent deformation and catastrophic failure.
Industrial Manufacturing: Monitoring expensive workpieces, thermal reactors, and gasifier parts in high-temperature furnaces and processing equipment.
Energy Production: Condition monitoring within power generation systems, including nuclear reactors and high-temperature heat exchangers, where traditional electronics cannot survive.
Passive RFID/IoT: Use as a chipless tag for asset tracking and environmental monitoring in harsh, high-heat industrial Internet of Things (IoT) environments.
Ceramic Component Testing: Integration into high-power microwave or RF ceramic components to monitor internal temperature fluctuations during operation.

View Original Abstract

A passive wireless sensor is designed for real-time monitoring of a high temperature environment. The sensor is composed of a double diamond split rings resonant structure and an alumina ceramic substrate with a size of 23 × 23 × 0.5 mm3. The alumina ceramic substrate is selected as the temperature sensing material. The principle is that the permittivity of the alumina ceramic changes with the temperature and the resonant frequency of the sensor shifts accordingly. Its permittivity bridges the relation between the temperature and resonant frequency. Therefore, real time temperatures can be measured by monitoring the resonant frequency. The simulation results show that the designed sensor can monitor temperatures in the range 200~~1000 °C corresponding to a resonant frequency of 6.79~~6.49 GHz with shifting 300 MHz and a sensitivity of 0.375 MHz/°C, and demonstrate the quasi-linear relation between resonant frequency and temperature. The sensor has the advantages of wide temperature range, good sensitivity, low cost and small size, which gives it superiority in high temperature applications.

Tech Support

Original Source

DOI: https://doi.org/10.3390/mi14040731

References

2021 - All-Ceramic LC Resonator for Chipless Temperature Sensing Within High Temperature Systems [Crossref]
2014 - Photoresponse of an electrically tunable ambipolar graphene infrared thermocouple [Crossref]
2019 - An experimental method for improving temperature measurement accuracy of infrared thermal imager [Crossref]
2014 - Technologies for printing sensors and electronics over large flexible substrates: A review [Crossref]
2013 - SAW-RFID enabled temperature sensor [Crossref]