Ferrite Circulator Thermal Management via Dielectric Attachments

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Solution Overview

Problem

Conventional ferrite waveguide circulators face challenges in achieving high power handling and thermal management due to limited thermal conductivity paths, leading to increased temperature rises and reduced performance in high-power applications.

Innovation Solution

The use of thermally conductive dielectric attachments on the side and face surfaces of the ferrite element, such as boron nitride, aluminum nitride, or beryllium oxide, to enhance heat transfer and minimize dielectric loading, thereby increasing the surface area contact and reducing the path length for thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional dielectric transformers are used for impedance matching, then impedance matching performance is improved, but thermal conductivity path is limited and temperature rise increases

Engineering Contradiction:
Improveimpedance matching performanceVSAvoidtemperature rise
Core Design Contradiction:
Measurement precisionVSTemperature

Solution Approach 1:

The patent adds thermal management in a new dimension by attaching thermally-conductive dielectric attachments to the side surfaces of the ferrite element, complementing the existing face surface attachments. This multi-dimensional thermal conduction approach maintains impedance matching while providing additional thermal pathways to reduce temperature rise.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent uses composite material structures combining ferrite elements with thermally-conductive dielectric materials (such as aluminum nitride, boron nitride, or beryllium oxide) to achieve both electrical impedance matching and enhanced thermal conductivity, resolving the contradiction between RF performance and thermal management.

Inventive Principle:
Principle #40Composite materials

2Power

If ferrite element size is increased to handle higher power, then power handling capability is improved, but thermal management becomes more difficult

Engineering Contradiction:
Improvepower handling capabilityVSAvoidthermal management
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The patent segments the thermal management function from the ferrite element itself by adding separate thermally-conductive dielectric attachments. These attachments act as dedicated thermal conduction pathways, allowing the ferrite element to be sized for power handling while the attachments manage the thermal dissipation independently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The thermally-conductive dielectric attachments serve as intermediary structures between the ferrite element and the heat sink. They mediate the thermal transfer, allowing high power handling in the ferrite element while providing efficient thermal conduction through the attachments to the heat sink, thus managing temperature rise.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Temperature

If thermally-conductive dielectric attachments are added to side surfaces, then thermal conductivity is improved, but device complexity increases

Engineering Contradiction:
Improvethermal conductivityVSAvoiddevice complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The thermally-conductive dielectric attachments serve multiple functions simultaneously: they provide thermal conduction pathways, maintains electrical insulation between the ferrite element and heat sink, and can contribute to impedance matching. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the thermal management function with the existing dielectric structure by using thermally-conductive dielectric materials for the attachments. This combines previously separate functions (electrical insulation and thermal management) into a single integrated component, reducing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 approach significantly improves the thermal performance of ferrite circulators, allowing them to handle higher average power levels and reducing temperature rises, making them suitable for a broader range of high-power applications and enhancing their survivability.

Implementation Method 1

at least one thermally-conductive dielectric attachment is affixed to at least one of the side surfaces of the ferrite element... significantly improves the thermal performance of ferrite circulators... enhancing heat transfer and minimizing dielectric loading, thereby increasing the surface area contact and reducing the path length for thermal conductivity

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

When a magnetizing field is created in this ferrite element, a gyromagnetic effect is created that can be used for circulating the microwave signal from one waveguide arm to another

Methodology Applied
Scientific EffectGyromagnetic effect: Electromagnetic Induction

Data Source

PatentEP1997184B1Ferrite waveguide circulator with thermally-conductive dielectric attachments
Publication Date: 2018.08.15 EMS TECHNOLOGIES INC
  • EP1997184B1 patent drawingFigure 1
  • EP1997184B1 patent drawingFigure 2~3
  • EP1997184B1 patent drawingFigure 4

AI summary

The present invention improves the geometry of ferrite circulators in order to increase the average power handling by decreasing the temperature rise in the ferrite and associated adhesive bonds. Embodiments of the present invention utilize dielectric attachments on the sides of the ferrite element, which maximizes the area of contact and minimizes the path length from the ferrite element out to the thermally conductive attachments.