Rogers high-frequency circuit boards, including RT-duroid® laminates, experience temperature rise when carrying direct current (DC) or radio frequency (RF) signals. The amount of heat generated depends on conductor properties, laminate material, current type, and thermal management strategies. Understanding these factors is crucial for reliable high-frequency PCB design.
Factors Affecting Temperature Rise
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Conductor Properties: Wider and thicker copper traces reduce resistance and heat generation. High-conductivity materials, such as copper, further minimize heating.
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Current Type: DC mainly generates heat through resistive losses, while RF signals can produce additional heating due to skin effect and dielectric losses.
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Laminate Properties: Materials like RT-duroid 5870 and 5880 have moderate thermal conductivity. Dielectric loss can increase heating at high frequencies.
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Environmental and Design Considerations: High ambient temperatures, limited airflow, and insufficient thermal vias can increase the PCB temperature.
Design Recommendations
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Thermal Management: Use thermal vias, heat sinks, and copper planes to efficiently dissipate heat.
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Copper Thickness and Trace Width: Increase trace dimensions to lower resistance and reduce heating.
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Material Selection: For power-dense or high-frequency applications, choose laminates with higher thermal conductivity.
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Impedance Control: Proper trace impedance reduces signal reflections and power loss.
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Simulation Tools: Use thermal and RF simulations to predict temperature rise in complex designs.
Practical Example
In a typical design, a standard RT-duroid PCB carrying moderate DC or RF currents will see a small temperature increase, which can be effectively managed with thermal vias and proper copper trace sizing. With good design practices, the board can operate reliably without overheating.
Conclusion
Proper thermal management is essential for high-frequency PCB reliability. By optimizing trace dimensions, using thermal vias and heat sinks, and selecting appropriate Rogers laminates, designers can ensure stable performance, maintain signal integrity, and extend the lifespan of high-frequency PCBs.
Temperature Rise Esitmations in Rogers High Frequency Circuit Boards Carrying Direct or RF Current
