GaN MMIC Micro Heat Exchanger Cooling for Radar Modules
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Solution Overview
Problem
Phased array radar systems using gallium nitride monolithic microwave integrated circuits face heat dissipation challenges with traditional cooling methods, which are inadequate for higher power levels and require modifications to existing equipment racks and sub-systems, and existing microcoolers lack the necessary heat transfer area and advanced materials for effective cooling.
Innovation Solution
The integration of a micro heat exchanger with a coolant input and output directly to the microwave integrated circuit, combined with a miniature pump or compressor, enables multiphase microfluidic cooling using highly conductive materials like silicon carbide and diamond, allowing for efficient heat dissipation without extensive architectural changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If gallium nitride monolithic microwave integrated circuits are used to operate at higher power levels, then power output is improved, but heat generation increases making traditional cooling methods inadequate
Solution Approach 1:
The cooling system is segmented into multiple functional components: a micro heat exchanger integrated directly with the GaN MMIC, a separate coolant circulation system with input/output ports, and a condenser system. This segmentation allows each component to be optimized for its specific function while working together to manage the high heat flux from the power amplifier circuitry.
Solution Approach 2:
A coolant fluid acts as an intermediary medium between the heat-generating GaN MMIC and the external cooling system. The coolant absorbs heat directly at the heat exchanger integrated with the MMIC, transports it through the circulation system, and dissipates it at the condenser, enabling effective heat removal without direct thermal contact between the high-power circuitry and external cooling components.
2Device complexity
If traditional heat transfer configuration is used, then system simplicity is maintained, but heat dissipation capability is insufficient for high power levels
Solution Approach 1:
The micro heat exchanger is merged directly with the GaN MMIC structure, integrating the cooling function into the circuitry itself. This integration minimizes thermal resistance and eliminates the need for separate, complex cooling assemblies, thereby improving heat dissipation capability while maintaining relative system simplicity.
3Temperature
If new heat transfer configuration is implemented to improve cooling, then heat dissipation is enhanced, but extensive architectural changes to radar system and subsystems are required
Solution Approach 1:
The coolant circulation system serves multiple functions: it cools the GaN MMIC through the integrated heat exchanger, provides structural support through the side rails, and enables thermal management across different power levels. This multi-functionality allows the same system architecture to handle both the improved cooling requirements and maintain compatibility with existing radar system configurations.
4Ease of manufacture
If existing microcoolers are used, then device availability is maintained, but they lack required heat transfer area and advanced materials for effective GaN MMIC cooling
Solution Approach 1:
The micro heat exchanger is constructed from diamond, an advanced material with exceptional thermal conductivity, and is integrated with silicon carbide substrates used in the GaN MMIC. This composite material approach provides the high heat transfer area and thermal management performance required for effective GaN MMIC cooling, while the microfabrication techniques used are compatible with existing semiconductor manufacturing processes.
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
This solution effectively manages heat generated by gallium nitride circuits at higher power levels, enabling operation up to 10-20 W/mm gate power levels while maintaining compatibility with existing radar system configurations and reducing thermal resistance, allowing for efficient heat transfer with reasonable pressure drops.
Implementation Method 1
coolant can be delivered directly to the integrated circuitry itself to thermally manage the circuitry
Implementation Method 2
multiphase microfluidic cooling of a GaN based transmit and receive integrated microwave module can be accomplished
Data Source
AI summary
A radar transmit and receive integrated microwave module with conductively cooled condenser side rails and one or more vacuum brazed fluid distribution manifold cold plates in fluid communication with the side rails. There are one or more transmit and receive modules on a cold plate. Each module includes a coolant input and a coolant output. One or more gallium nitride monolithic microwave integrated circuits are within each transmit and receive module and each include a micro heat exchanger in fluid communication with the coolant input and the coolant output of the transmit and receive module to directly cool the gallium nitride monolithic microwave integrated circuit.