Heat Transfer Analysis and Validation for Improving Thermal Dissipation Characteristics of Miniaturized Transmitter = 초소형 송신기의 방열 특성 개선을 위한 열전달해석 및 검증

다국어 초록 (Multilingual Abstract)

This study focuses on the cooling design of Miniaturized Transmitter, addressing structural and spatial constraints in response to demands for miniaturization and high performance. Due to the anticipated increase in the use of high-density and generating components and integration levels, it is necessary to improve the thermal dissipation characteristics of Miniaturized Transmitter to ensure adequate temperature margins. To achieve this, Graphite and Copper sheet are applied according to the mounting environment of Miniaturized Transmitter. The study is divided into a basic model and models with each type of sheet applied. To ensure thermal reliability under operational environmental requirements, thermal transfer analysis and actual measurements were conducted for verification. Considering the boundary conditions where Miniaturized Transmitter operates within a sealed space without forced convection and is mounted on an internal structure, thermal transfer analysis at both ambient and high temperatures confirmed that the primary heat-generating components operate within their permissible temperature limits.

By applying the copper sheet to secure additional temperature margins for the components, an increase of over 6% in temperature margin was achieved compared to the basic model. Furthermore, the correlation analysis between the simulation and experimental results demonstrated a discrepancy of only 1%, proving the reliability of the simulation results.

To minimize the air gap between the copper sheet and the bottom surface of housing, applying a bimetallic interface bonding method such as brazing is expected to achieve high thermal conductivity efficiency, thereby securing additional temperature margins.

Keywords: Miniaturized Transmitter; Thermal Analysis; Thermal Interface Material; Graphite; Copper; Convective Heat Transfer Coefficient

국문 초록 (Abstract)

본 연구는 초소형 송신기의 소형화 및 고성능화 요구에 따라, 구조적 및 공간적 제약을 고려한 냉각 설계를 수행하였다. 소형화와 고성능화로 인해 고밀도 발열 소자의 사용 증가와 집적도 증가가 예상되므로, 초소형 송신기의 방열 특성 개선을 통해 온도 마진을 확보하기 위해 Graphite 및 Copper 소재의 Sheet를 초소형 송신기의 장착 환경에 맞추어 적용하였다. 기본 모델과 각 Sheet가 적용된 모델로 구분하여, 운용 환경 요구에 따른 열적 신뢰성을 확보하기 위해 열전달 해석 및 실제 측정을 통해 검증하였다.

초소형 송신기는 강제 대류가 없는 밀폐된 공간과 내부 구조체에 장착되어 운용되는 경계 조건을 고려하여 상온 및 고온 열전달 해석을 수행한 결과, 주요 발열 소자가 동작 허용 온도 기준 내에서 작동함을 확인할 수 있었다. 소자의 추가적인 온도 마진 확보를 위해 Copper Sheet를 적용한 결과, 기본 모델 대비 6% 이상의 온도 마진을 확보하였다. 또한, 해석 및 실험 결과에 대한 상관관계를 분석한 결과, 1%의 오차율을 보여 해석 결과가 신뢰할 수 있음을 입증하였다.

Copper Sheet과 초소형 송신기 하우징 바닥면 사이의 공기층(Air Gap)을 최소화하기 위해 써멀구리스 또는 이중금속 계면 접합(브레이징) 방식을 적용하면 높은 열전도 효율을 달성하여 추가적인 온도 마진을 확보할 수 있을 것으로 기대된다.

주요어 : 송신기, 열전달해석, 열계면물질, 그라파이트, 구리, 대류열전달계수

목차 (Table of Contents)

• Table of Contents ⅰ
• Symbol Table ⅳ
• List of Figures ⅴ
• List of Tables ⅶ
• Abstract ⅷ
• Chapter 1 Introduction 1
• 1.1 Background and Trends of Research 1
• 1.2 Necessity of the Research 2
• 1.3 Research Objective 2
• Chapter 2 Overview and Design of Miniaturized Transmitter 4
• 2.1 Function of the Transmitter 4
• 2.2 Mounting Environment of Transmitter 5
• 2.3 Shape and Specifications of Transmitter 6
• 2.4 Design and Fabrication of Miniaturized Transmitter 7
• Chapter 3 Thermal Transfer Analysis and Methodology of Miniaturized
• Transmitter 10
• 3.1 Analysis Modeling for Thermal Transfer Analysis 10
• 3.1.1 Analysis Model and Simplification 10
• 3.1.2 Materials and Properties 12
• 3.2 Thermal Transfer Analysis Method 13
• 3.2.1 Thermal Transfer Analysis Solution 13
• 3.2.2 Physical Mechanisms of Natural Convection 15
• 3.3 Experimental Setup and Method 17
• 3.3.1 Ambient Temperature Experimental Setup and Method ·· 17
• 3.3.2 Experiment for Surface Temperature Measurement 18
• 3.3.3 Experiment for Temperature Measurement of Heat-Generating
• Components 19
• 3.4 Thermal Transfer Analysis Condition 21
• 3.4.1 Finite Component Method 21
• 3.4.2 Boundary Condition 22
• 3.4.3 Heat Generation and Operating Temperature of Each
• Component 24
• Chapter 4 Comparison of Thermal Transfer Analysis and Experimental
• Result 26
• 4.1 Result of Thermal Transfer Analysis 26
• 4.1.1 Model Ⅰ Ambient Temperature Thermal Transfer Analysis
• Result 26
• 4.1.2 Model Ⅱ Ambient Temperature Thermal Transfer Analysis
• Result 28
• 4.1.3 Model Ⅲ Ambient Temperature Thermal Transfer Analysis
• Result 30
• 4.1.4 Comparison of Ambient Temperature Thermal Transfer
• Analysis Result 32
• 4.1.5 Model Ⅰ High Temperature Thermal Transfer Analysis
• Result 33
• 4.1.6 Model Ⅱ High Temperature Thermal Transfer Analysis
• Result 35
• 4.1.7 Model Ⅲ High Temperature Thermal Transfer Analysis
• Result 37
• 4.1.8 Comparison of High Temperature Thermal Transfer
• Analysis Result 39
• 4.2 Experimental Result 40
• 4.2.1 Model Ⅰ Experimental Result 40
• 4.2.2 Model Ⅱ Experimental Result 41
• 4.2.3 Model Ⅲ Experimental Result 42
• 4.2.4 Experimental Results for Temperature Measurement of Heat-
• Generating Component 43
• Chapter 5 Conclusion 45
• Reference 47
• 국문요지 50
• 감사의 글 51
• 영문연구윤리서약서 52
• 국문연구윤리서약서 53