High Frequency Circuit Thermal Management via Vertical Stacking

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Solution Overview

Problem

High frequency circuits face challenges in achieving a small size while minimizing signal loss and ensuring effective heat dissipation, as existing designs either result in longer connections and increased size or compromise on heat dissipation for reduced signal loss.

Innovation Solution

The solution involves a high frequency circuit design where the high frequency device is integrated into a substrate with a conductor layer for heat dissipation, using short wiring distances and thermal connections to reduce signal loss and enhance heat dissipation, achieved through a multilayer structure with conductor layers and dielectric layers that allow for efficient signal propagation and heat transfer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If devices are disposed in a planar direction of a substrate, then heat dissipation is improved, but connection length increases and size becomes larger

Engineering Contradiction:
Improveheat dissipationVSAvoidconnection length
Core Design Contradiction:
TemperatureVSLength of moving object

Solution Approach 1:

The patent transitions from planar device arrangement to three-dimensional vertical stacking, where multiple high frequency devices are disposed at different heights above the substrate. This dimensional change allows heat dissipation through the substrate thickness direction while maintaining short horizontal connection lengths between devices and conductor layers.

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

2Loss of energy

If wiring between devices is shortened, then size is reduced and signal loss is minimized, but heat dissipation capability is compromised

Engineering Contradiction:
Improvesignal lossVSAvoidheat dissipation
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The patent separates the functions of signal transmission and heat dissipation into distinct conductor layers. Signal conductor layers provide short vertical connections for minimal signal loss, while dedicated heat dissipation conductor layers are positioned to maximize thermal contact with device back surfaces, allowing both objectives to be achieved simultaneously through functional segmentation.

Inventive Principle:
Principle #1Segmentation

3Temperature

If conductor layers are added for heat dissipation, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The substrate serves multiple functions simultaneously: it provides mechanical support, establishes electrical connections through integrated conductor layers, and acts as a heat dissipation path. The conductor layers are designed to fulfill both signal transmission and thermal management roles, reducing the need for separate dedicated heat sinks or cooling structures.

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

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 design enables a compact high frequency circuit with reduced signal loss and improved heat dissipation characteristics, suitable for communication equipment applications.

Implementation Method 1

the device back surface of the first high frequency device is thermally connected to the conductor layer for heat dissipation

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3432353B1High frequency circuit
Publication Date: 2021.09.01 MITSUBISHI ELECTRIC CORP
  • EP3432353B1 patent drawingFigure 1~3
  • EP3432353B1 patent drawingFigure 4~5
  • EP3432353B1 patent drawingFigure 6~7

AI summary

A printed wiring board includes conductor layers, a core layer having an opening, and a build-up layer. A high frequency device placed within the opening is installed such that a mirror surface is thermally connected to a conductor layer for heat dissipation facing the opening from a lower surface side of the core layer, and terminals on the terminal surface are electrically connected to conductor layers formed on an upper surface side of the core layer.