RT-duroid 5870 laminates are high-performance microwave and radio frequency (RF) circuit materials manufactured by Rogers Corporation. These laminates are widely used in high-frequency applications due to their low dielectric constant, low loss tangent, and excellent stability under various environmental conditions.

1. Key Features of RT-duroid 5870

1. Low Dielectric Constant (ϵr=2.33\epsilon_r = 2.33ϵr​=2.33):
   • Minimizes signal delay and ensures efficient propagation of electromagnetic waves.
   • Suitable for high-speed digital and RF circuits.
2. Low Loss Tangent (tan⁡δ\tan \deltatanδ):
   • Typically 0.0012 at 10 GHz, ensuring minimal signal loss.
   • Ideal for applications requiring low insertion loss.
3. PTFE-based Composition:
   • The laminate is reinforced with glass microfibers, providing mechanical stability while maintaining the desirable electrical properties of PTFE.
4. Low Moisture Absorption:
   • Moisture absorption is typically less than 0.02%, making it suitable for humid environments.
   • Ensures consistent performance in varying environmental conditions.
5. Temperature Stability:
   • Can operate over a wide temperature range, typically from -200°C to +200°C.
   • Exhibits minimal thermal expansion, reducing stress on solder joints and other components.
6. Chemical Resistance:
   • Resistant to most chemicals, making it durable in harsh environments.

2. Applications of RT-duroid 5870

1. High-Frequency Circuits:
   • Antennas, amplifiers, and filters for RF and microwave communication systems.
2. Aerospace and Defense:
   • Radar systems, satellite communication devices, and avionics.
3. Space Applications:
   • Low outgassing properties make it ideal for use in vacuum and space environments.
4. Automotive Radar Systems:
   • Used in advanced driver-assistance systems (ADAS) and vehicle-to-everything (V2X) communication.
5. Medical Devices:
   • High-frequency imaging systems and sensors.

3. Typical Properties of RT-duroid 5870

Property	Value	Notes
Dielectric Constant (ϵr\epsilon_rϵr​)	2.33	± 0.02 tolerance.
Loss Tangent (tan⁡δ\tan \deltatanδ)	0.0012 @ 10 GHz	Ensures low signal loss.
Moisture Absorption (%)	< 0.02	High reliability in humid environments.
Thermal Conductivity (W/m·K)	0.2	Adequate heat dissipation for RF devices.
Operating Temperature (°C)	-200 to +200	Wide temperature range for various uses.
Peel Strength (N/mm)	0.7	Good adhesion of copper cladding.
Density (g/cm³)	~2.1	Lightweight material.

4. Fabrication Considerations

1. Drilling and Machining:
   • Use carbide or diamond-coated tools to prevent fraying of the PTFE/glass microfiber composite.
2. Etching and Metallization:
   • Chemical treatments may be required to enhance copper adhesion due to PTFE’s inert surface.
3. Lamination:
   • Handle with care to avoid contamination and maintain consistent dielectric properties.
4. Thermal Expansion Management:
   • While RT-duroid 5870 has low CTE\text{CTE}CTE, ensure compatible materials are used to prevent stress during thermal cycling.

5. Comparison with RT-duroid 5880

Feature	RT-duroid 5870	RT-duroid 5880
Dielectric Constant (ϵr\epsilon_rϵr​)	2.33	2.20
Loss Tangent (tan⁡δ\tan \deltatanδ)	0.0012	0.0009
Reinforcement Material	Glass microfiber	Glass microfiber
Cost	Moderate	Slightly higher
Primary Application	Broad RF and microwave use	Ultra-low loss RF systems

6. Advantages

• High signal integrity for RF and microwave applications.
• Stable performance under extreme environmental conditions.
• Reliable for both commercial and aerospace applications.

7. Disadvantages

• Higher cost compared to standard FR-4 materials.
• PTFE-based laminates require specialized handling and fabrication techniques.