Spring Mounted Chip Termination Thermal Mismatch
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Solution Overview
Problem
Conventional chip terminations in RF and microwave circuits face thermal expansion mismatch issues due to the use of ceramic chips mounted on copper flanges, leading to poor thermal performance and high voltage standing wave ratio (VSWR).
Innovation Solution
An integrated spring mounted chip termination system that eliminates the need for a mounting flange by directly attaching the chip termination to a heatsink using a formed ground spring, improving thermal conductivity and reducing thermal expansion mismatch, while enhancing power handling and VSWR through increased ground contact on the chip termination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic chip is mounted on a copper flange, then the chip termination can be used for heatsinking, but thermal expansion mismatch occurs leading to poor thermal performance and high VSWR
Solution Approach 1:
The patent removes the copper flange from the assembly, extracting the source of thermal expansion mismatch. The chip termination is mounted directly to the heatsink without the intermediate flange, eliminating the CTE incompatibility between copper and ceramic materials while maintaining effective heatsinking through direct thermal contact.
Solution Approach 2:
The patent employs a composite mounting structure where the chip termination is directly coupled to the heatsink, creating a unified thermal path. This composite approach integrates the ceramic chip, mounting substrate, and heatsink into a single thermal management system that optimizes heat transfer while avoiding material incompatibility issues.
2Area of stationary object
If a conventional flange mount is used, then the chip termination can be mounted, but the profile is larger and ground contact is insufficient
Solution Approach 1:
The patent merges the mounting function and ground contact function into a single integrated structure. The heatsink serves both as the mechanical mounting platform and as the ground reference, eliminating the need for separate flange and ground path components. This integration maximizes ground contact area while simplifying the overall device structure.
Solution Approach 2:
The heatsink is designed to perform multiple functions simultaneously: it provides mechanical support for mounting the chip termination, serves as the ground reference for RF signals, and acts as the thermal management system. This multi-functional approach reduces the number of components needed while improving ground contact and reducing profile.
3Temperature
If a copper flange is used for mounting, then the assembly can be constructed, but thermal conductivity is reduced due to thermal expansion mismatch
Solution Approach 1:
The copper flange is removed from the assembly, eliminating the thermal barrier it creates through thermal expansion mismatch. Direct mounting of the chip termination to the heatsink creates an uninterrupted thermal path, maximizing thermal conductivity without the intermediate copper layer that would otherwise impede heat transfer.
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 integrated spring mounted chip termination system improves power dissipation and RF performance by eliminating thermal expansion mismatch and increasing ground contact, resulting in reduced profile and enhanced VSWR across the frequency range.
Implementation Method 1
a formed ground spring connected to the ground contact of the chip termination, the formed ground spring configured to attach the chip termination to the heatsink
Implementation Method 2
chip terminations are used at the end of a circuit to terminate a signal to ground by converting RF energy into heat
Data Source
AI summary
An integrated spring mounted chip termination for converting energy of a circuit into heat to be absorbed by a heatsink. The integrated spring mounted chip termination includes an input tab configured to connect to the circuit. The integrated spring mounted chip termination also includes a chip termination having a top surface. The chip termination includes an input contact located on the top surface and configured to connect to the input tab, a resistor element located on the top surface and connected to the input contact, and a ground contact located on the top surface and connected to the resistor element. The integrated spring mounted chip termination also includes a formed ground spring connected to the ground contact of the chip termination, the formed ground spring configured to attach the chip termination to the heatsink, such that the chip termination and the heatsink are in contact.