Liquid cold plates are one of the most effective ways to remove heat from high-power defense electronics—especially radar, EW, power conversion, and advanced RF systems. As GaN technology, digital signal processing, and high-density payload electronics continue to increase power density, air cooling alone is no longer sufficient. Program teams are turning to liquid cooling to maintain performance, prevent thermal runaway, and ensure long-term mission reliability.

This guide provides a deep, engineering-focused look at what liquid cold plates are, how they work, when they’re used, and the key considerations for aerospace and defense applications.

What Is a Liquid Cold Plate?

A liquid cold plate is a thermal management device that transfers heat from an electronic component to a liquid coolant flowing through internal channels or tubes. Instead of relying on air as the heat transfer medium, liquid cold plates use a coolant—typically water/glycol, PAO, or other dielectric fluids—to remove heat far more efficiently.

At the most basic level, a liquid cold plate includes:

•  A metal base plate (typically aluminum or copper)
•  Internal fluid channels (machined, brazed, or gun-drilled)
•  Inlet/outlet ports for coolant flow
•  Mounting surfaces for electronics modules, RF devices, or power components
•  Seals, O-rings, or welded joints depending on design requirements

Because liquid has much higher thermal capacity than air, cold plates can manage 5–10× the heat flux of typical air-cooled solutions.

Why Liquid Cooling Is Rising Across Defense Programs

GaN Devices Produce Extreme Heat Flux

Modern GaN-based Radar and EW systems generate significant thermal loads. Junction temperatures quickly approach failure thresholds if heat is not removed efficiently.

Liquid cold plates provide:

•  Higher heat transfer coefficients
•  Lower thermal resistance
•  Better temperature uniformity across RF devices

SWaP Pressures Leave No Space for Air Cooling

In airborne or missile applications, system size shrinks while power increases. Fans and heat sinks cannot keep up.

Improved Reliability and Reduced Thermal Cycling

Air cooling causes large temperature swings, especially in varying altitude environments. Liquid cooling keeps electronics more stable, extending component life.

Future System Requirements

Next-generation platforms—hypersonic vehicles, directed energy concepts, and new space architectures—are driving thermal demands. Liquid cold plates are fast becoming a baseline requirement.

How Liquid Cold Plates Work

1. Heat transfers into the metal baseplate.
2. Coolant moves through internal channels.
3. Heat is absorbed by the coolant.
4. The coolant carries heat away to a heat exchanger.

Types of Cold Plate Channel Designs

• Machined & brazed cold plates
• Tube embedded cold plates
• Additive manufactured cold plates

Common Coolants

•  PAO
•  Ethylene glycol/water
•  Dielectric fluids
•  Space-rated fluids

Liquid Cold Plates for RF & Defense Electronics

Applications include:

•  RF power amplifiers
•  Radar & EW LRUs
•  Power conversion modules
•  Space payload electronics

Critical Design Considerations

•  Thermal resistance & uniformity
•  Structural requirements
•  Vacuum vs. dip brazing
•  Corrosion management
•  Pressure drop constraints

Manufacturing Factors

•  Tolerance control
•  Cleanliness & leak testing
•  Brazing quality
•  Precision machining
•  Program manufacturing stability

Where Liquid Cold Plates Are Used

•  AESA radar
•  EW systems
•  Missile guidance and tracking electronics
•  Spacecraft payloads
•  High-power computing systems

Why Work With Vitesse

•  Precision machining
•  Automated dip-brazing & vacuum brazing
•  Experience in radar, EW, missile, and space programs
•  Scalable production capability

Conclusion

Liquid cold plates are essential for high-power defense electronics. They provide performance, reliability, and SWaP advantages needed for mission success.