Here is the professional translation and structured organization of the board-to-board connector technical document:

Chapter 1 Fundamental Concepts & Working Principles
1.1 Definition & Functional Positioning
Board-to-board connectors are core components in electronic systems enabling signal/power interconnections between PCBs, with three essential functions:

• Electrical interconnection: Establish reliable low-impedance conductive paths
• Mechanical support: Provide physical alignment and stress buffering
• Modular design: Enable rapid module assembly/maintenance

1.2 Typical Structural Composition

1.3 Working Principle Diagram (Illustration)

Chapter 2 Technical Characteristics Analysis
2.1 Core Performance Indicator Matrix

2.2 Electrical Characteristics Analysis
Contact resistance model:

R_c = \frac{ρ}{2a} + \frac{σ}{A}

Where:
ρ = Material resistivity
a = Contact point radius
σ = Surface film resistivity
A = Actual contact area

2.3 Mechanical Performance Highlights
Mating force control:

• Bicurved contact design reduces 40% mating force vs single-point
• Optimal plating: Au(0.25μm)+Ni(1.5μm)
• 5° lead-in angle decreases peak force 30%

Chapter 3 Evolution & Technological Development
3.1 Product Classification
By pitch:

• Standard: 2.54mm/2.0mm
• Fine: 1.27mm/1.0mm
• Ultra-fine: 0.5mm/0.4mm

By contact type:

• Spring contact (75% market share)
• Rigid press-fit
• Welded (laser)

Emerging technologies:

• Wireless connectors (60GHz mmWave)
• Optical interconnects (≥28Gbps)
• Anisotropic conductive film

Chapter 4 Material Science & Manufacturing
4.1 Key Material Technologies
Contact material evolution:

• Traditional: Brass (28%IACS)
• Improved: Phosphor bronze (50%IACS)
• Advanced: Cu-Ni-Si alloy (800MPa, 45%IACS)

Insulation material comparison:

Chapter 5 Testing & Validation
5.1 Comprehensive Testing
Initial verification:

• Solderability (245℃±5℃ dip)
• Coplanarity (<0.1mm)

Environmental tests:

• Thermal cycling (-55℃↔+125℃, 1000 cycles)
• Damp heat (85℃/85%RH, 1000h)

Mechanical tests:

• Mating cycles (20,000)
• Vibration (20-2000Hz, 3-axis)

Chapter 6 Applications & Selection
6.1 Typical Applications

• 5G Communications: Backplane connectors (112Gbps)
• EV: High-voltage connectors (1000VDC)
• Medical: IP68 waterproof
• Industrial: Vibration-resistant (10-2000Hz)

6.2 Selection Matrix