Wireless Temperature Sensor With Parasitic Antenna
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Solution Overview
Problem
Existing remote wireless temperature measurement systems face challenges such as delicate tag/switch connections, antenna de-tuning due to conductive objects, and potential damage from high temperatures, limiting their effectiveness and ease of integration into objects being measured.
Innovation Solution
A wireless temperature sensor system with a transponder and a parasitic antenna, where the parasitic antenna includes a temperature-sensitive transducer that changes impedance at predetermined temperatures, eliminating the need for physical connections and allowing for thermal insulation, enabling reliable temperature measurement beyond the tag's rated operating temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tag is physically connected to the thermal switch using fine connection wires and connectors, then the temperature measurement function is achieved, but the device becomes difficult to incorporate within the object and the connection becomes delicate
Solution Approach 1:
The system divides the temperature sensing function into two separate components: a thermal switch that contacts the object and a transponder tag that communicates wirelessly. This segmentation eliminates the need for physical connections between the tag and switch, solving both the delicate connection and integration difficulty problems.
Solution Approach 2:
A parasitic antenna is introduced as an intermediary element that couples the transponder tag to the thermal switch through electromagnetic induction. This allows energy and signal transfer without direct physical connection, eliminating connection reliability issues while maintaining functional integration.
2Ease of manufacture
If the tag is placed close to the object to facilitate incorporation, then the manufacturing difficulty is reduced, but the antenna becomes de-tuned by the conductive object and communication is compromised
Solution Approach 1:
The parasitic antenna acts as an intermediary that decouples the transponder tag from direct proximity requirements with the object. The thermal switch can be positioned close to the object for easy integration, while the tag remains at an optimal distance for communication through the parasitic antenna's electromagnetic coupling.
3Reliability
If the connection between switch and tag is lengthened to eliminate adverse effects from the object, then the communication is enhanced, but the difficulty of incorporation into the object increases
Solution Approach 1:
The system separates the thermal switch (which remains close to the object) from the transponder tag (which can be positioned optimally for communication). The parasitic antenna enables functional connection without requiring physical proximity, achieving both good communication and easy integration.
4Temperature
If the tag/switch combination is used to measure high object temperatures, then the temperature measurement range is extended, but the integrated circuitry of the tag may be destroyed or tag communication may be disrupted
Solution Approach 1:
The system separates the high-temperature exposure function (thermal switch contacting the object) from the sensitive electronics (transponder tag). The thermal switch can withstand high temperatures while the tag remains in a cooler zone, extending the measurement range without compromising tag integrity.
Solution Approach 2:
The parasitic antenna serves as a thermal and electrical intermediary, allowing the thermal switch to be in direct contact with the high-temperature object while the transponder tag communicates through electromagnetic coupling from a protected position, preventing thermal damage to the electronics.
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 system provides reliable, wireless temperature measurement across a wide range of objects, including food servingware, with improved integration and durability, allowing for accurate temperature sensing without damaging the integrated circuitry and enabling additional features like data storage.
Implementation Method 1
the parasitic antenna includes a temperature-sensitive transducer operable to change the impedance value of the parasitic antenna when the object being temperature-sensed reaches a predetermined temperature
Implementation Method 2
The sensor includes a transponder including a transponder antenna and a circuit operably coupled with the transponder antenna, the circuit operable to extract energy from electromagnetic signals received by the transponder antenna
Data Source
AI summary
Temperature measurement systems (20) include a temperature sensor (22) and an electronic signal interrogator (24). The temperature sensor (22) has a transponder (26) equipped with an antenna (28), and a separate parasitic antenna (32) with a temperature-sensitive transducer (34, 68-74, 78a-84a), while the interrogator (24) has a transmitter (42) and antenna (40). The sensor (22) is designed to be placed in thermal contact with an object to be temperature-measured, with the interrogator (24) placed in proximity to the object. The systems (20) may be used with food servingware domes (88, 114), which can be preheated and placed over a food-bearing plate to maintain the temperature of the food.