High-Temperature Antenna Connection for SAW Sensor Reliability
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Solution Overview
Problem
Existing electrical connections for high-temperature applications, such as surface acoustic wave sensors, face challenges with radio frequency losses and mechanical instability due to the limitations of solder joints, which melt at high temperatures and lose effectiveness over time.
Innovation Solution
A metal stud with a groove is used to connect the antenna pole to the electrical component, providing a heat-resistant and mechanically stable connection that improves antenna operation and heat transfer, while an insulating coating prevents grounding and allows for precise temperature measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a solder joint is used to connect the antenna to the electrical component, then the connection is easy to manufacture, but the connection loses effectiveness at high temperatures exceeding 300°C
Solution Approach 1:
The patent changes the material parameter of the connection from solder (low melting point) to a metal pad with high melting point material. This parameter change allows the connection to withstand temperatures exceeding 300°C while maintaining electrical conductivity and mechanical strength, directly resolving the high-temperature reliability issue.
Solution Approach 2:
The patent replaces the solder joint mechanical system with a metal pad system that uses mechanical attachment (screws, clips, or interference fit) combined with direct metal-to-metal electrical contact. This substitution eliminates the melting point limitation of solder while maintaining ease of manufacture through standardized mechanical fastening methods.
2Reliability
If a cement dome is used to protect the solder joint, then the solder joint is protected from melting, but the connection ages poorly and loses effectiveness over time
Solution Approach 1:
The patent extracts and eliminates the cement dome protection layer entirely. Instead of protecting the solder joint indirectly through encapsulation, the design uses a metal pad that inherently withstands high temperatures without requiring protective encapsulation. This removal of the cement dome eliminates the aging and effectiveness loss issues associated with the encapsulation material.
Solution Approach 2:
The patent replaces the cement dome (which degrades over time) with a metal pad that is inherently durable and does not require replacement or maintenance. The metal pad maintains its protective and conductive functions indefinitely under high-temperature conditions, eliminating the time-dependent degradation problem.
3Reliability
If a thick cement dome is used to protect the connection, then the solder joint is adequately protected, but the antenna performance deteriorates due to increased distance from the antenna element
Solution Approach 1:
The patent removes the cement dome entirely, eliminating the source of RF losses caused by increased distance between the antenna element and the connection point. The metal pad provides adequate protection and electrical connection without requiring the thick encapsulation that causes RF energy loss.
4Temperature
If a metal pad is used instead of solder joint, then high temperature resistance is improved, but the manufacturing complexity increases
Solution Approach 1:
The metal pad serves multiple functions simultaneously: it provides electrical conductivity, mechanical support, thermal management, and high-temperature resistance. This multi-functionality consolidates what would otherwise require multiple separate components (solder joint, protective dome, mechanical support structure), actually reducing overall device complexity while achieving superior temperature resistance.
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 solution ensures reliable electrical and mechanical connections at high temperatures, maintaining effectiveness over multiple melting/solidification cycles and enhancing the precision of temperature measurements.
Implementation Method 1
the metal pad allows for good heat transfer between the object whose temperature is being measured and the sensor
Implementation Method 2
surface acoustic wave (SAW) temperature sensors
Implementation Method 3
passive components with elastic surface waves arranged on single-crystal or composite substrates (piezoelectric films or layers deposited or transferred onto substrates)
Data Source
Figure 1~5
Figure 4a~6c
AI summary
The invention relates to an electrical device adapted to operate at a high operating ambient temperature, which device comprises an electrical component (10a, 10b) mounted inside a casing (20), a transmission/reception antenna (30a, 30b) and at least one electrical and mechanical connection between the electrical component and the antenna, the electrical and mechanical connection comprising: - a metal pad (40a, 40b) positioned under the casing, the antenna being connected to said pad; - an electrical connection tab (11) having a first end connected to the electrical component; and fixing means (50) adapted to secure the pad and a second end of the connection tab of the component. Application, for example, to the production of temperature sensors of the surface guided elastic wave type.