Introduction

Rogers RT/duroid 6202 is a ceramic-filled fluoropolymer composite material designed for fabricating high frequency radio frequency (RF) and microwave printed circuit boards (PCBs). This article provides an overview of Rogers 6202, examining its properties, composition, key characteristics, fabrication guidelines and typical applications that use this material.

What is Rogers RT/duroid 6202?

Rogers RT/duroid 6202, also referred to as RO6202, is an advanced dielectric substrate engineered specifically for high frequency microwave applications requiring stable electrical performance. Some key features include:

• Ultra-low and consistent dielectric constant of 2.94
• Low loss tangent of 0.0015 at 10 GHz
• Thermoplastic fluoropolymer resin system
• Woven E-glass reinforced construction
• Excellent dimensional stability
• Lead-free compatibility and RoHS compliant
• Usable over a wide frequency range up to mmWave bands
• Sheets available in thicknesses from 0.05 mm to 3.18 mm

With these characteristics optimized for low loss and tight dielectric tolerances, Rogers 6202 provides a high performance substrate choice for microwave PCB fabrication.

Dielectric Properties

The critical dielectric characteristics that make Rogers 6202 suitable for microwave frequencies are:

Stable Dielectric Constant

• Consistent relative permittivity of 2.94 from 1 to 40 GHz
• Extremely tight tolerance of ±0.04
• Near zero moisture absorption

Low Loss Tangent

• Loss tangent of 0.0015 at 10 GHz
• Dissipation factor less than 0.0020 up to 18 GHz
• Enables high quality factors for RF circuits

Thermal Stability

• Dielectric constant variation of only -30ppm/°C
• Retains stable electrical properties over temperature

Mechanical Characteristics

In addition to its electrical performance, Rogers 6202 also demonstrates good mechanical and thermal properties:

• Tensile modulus of 2070 MPa for dimensional stability
• Tensile strength of 48 MPa
• Flexural strength of 62 MPa
• Lead-free assembly compatible with Tg of 280°C
• Withstands multiple reflows up to 288°C peak temperature
• Low z-axis CTE of 25 ppm/°C
• Good thermal conductivity of 0.69 W/mK

The woven fiberglass reinforcement boosts 6202’s mechanical rigidity and strength compared to unfilled PTFE substrates.

Laminate Composition

Rogers RT/duroid 6202 combines the attributes of several materials in its composite construction:

• PTFE fluoropolymer resin – Gives excellent electrical performance and stability across frequency range and temperatures. Also provides good chemical resistance.
• Ceramic filler – Further enhances dielectric properties and thermal conductivity.
• E-glass microfiber reinforcement – The woven glass fabric multilayer construction offers dimensional stability and improves mechanical rigidity.
• Fluoropolymer impregnation – The PTFE resin fully impregnates the glass layers for robust structure and electrical integrity.

This precise combination of resins, reinforcements and fillers gives RT/duroid 6202 a compelling property mix for microwave PCB fabrication.

Common Designations

Rogers RT/duroid 6202 material is also available under several variants:

• RO6202 – Regular version
• RO6202CH – Circuit substrate prepreg
• RO6202DK – Prepreg with increased melt flow
• RO6202LoPro – Thinner laminates
• RO6202PR – Polyimide reinforced for extreme environments

The core substrate properties remain similar between these versions, with the suffixes indicating specialized constructions suited for particular PCB design needs.

Availability

Rogers RT/duroid 6202 laminates are available globally through authorized Rogers distributors or directly from Rogers Corporation. The material is offered in sheet sizes up to 18 x 24 inches (457 x 610 mm).

Standard thicknesses range from 0.05 mm (2 mils) up to 3.18 mm (125 mils). Non-standard custom thicknesses can also be produced on request.

Fabrication Guidelines

Rogers provides specific material handling instructions and PCB fabrication guidelines when using their RF materials like RT/duroid 6202:

• Allow ±0.05mm thickness tolerance in layouts
• Ensure chemical compatibility if combining with bonding prepregs
• Limit unsupported conductor spans between layers
• Use two-sided bonded construction above 3.18mm thickness
• Employ multiple small diameter thermal vias for heat dissipation
• Maintain 0.1-0.2mm finished hole annular rings
• Minimize Z-axis lamination pressure and temperature

Following these recommendations helps maximize both fabrication yield and high frequency electrical performance.

Typical Applications

Some example microwave applications where Rogers RT/duroid 6202 provides an excellent PCB substrate choice include:

• Satellite communication systems
• 5G cellular infrastructure equipment
• Automotive radar and sensors
• Aerospace avionics and antenna substrates
• Medical radiology equipment
• Test and measurement instrumentation
• Microwave radio/wireless backhaul links
• Military electronic warfare systems
• High energy research lab equipment

The stable dielectric properties and low loss of 6202 support reliable operation up to Ku band and beyond in these microwave systems.

Benefits of Rogers RT/duroid 6202

Rogers 6202 laminates offer these benefits when used for RF and microwave PCB fabrication:

• Extremely tight control of dielectric constant for precise impedances
• Low loss tangent to reduce signal attenuation
• High thermal conductivity for heat dissipation in RF designs
• Excellent dimensional stability over temperature due to reinforced construction
• Withstands soldering processes required for component attachment
• Lightweight substrate suitable for weight-sensitive applications
• Reduced EMI/RFI interference due to woven glass presence
• Good availability and reasonable cost

Conclusion

Rogers RT/duroid 6202 laminates provide PCB designers with an advanced radio frequency substrate engineered for stable, low loss performance vital in microwave and millimeter wave circuits. The highly controlled dielectric properties, woven glass reinforcement and ceramic filling make 6202 a material of choice for applications like radar sensors, 5G equipment, satellite links and test instrumentation operating up to 40 GHz frequencies. With the rapid growth in cutting-edge microwave systems, Rogers 6202 delivers an optimal platform for transforming these high frequency designs into reality.

Frequently Asked Questions

What are common copper weights used with Rogers 6202 material?

1/2 oz (18 um) to 2 oz (70 um) electrodeposited or rolled copper foils are typical for microwave circuits on Rogers 6202. The 1 oz (35 um) weight provides a good balance of thickness for many applications.

Does Rogers 6202 require special handling or storage precautions?

No special handling is needed beyond standard PCB material controls. Rogers 6202 has unlimited shelf life at room temperature and typical humidity levels.

What makes 6202 different from other popular RF laminates like RT/duroid 5880?

RT/duroid 6202 has slightly lower loss tangent, better thermal performance and reduced moisture absorption compared to 5880. But both provide excellent high frequency PCB performance.

Can you combine Rogers 6202 with FR4 layers to make multilayer boards?

Yes, Rogers 6202 layers can be interleaved with properly chosen FR4 prepregs to create hybrid multilayer boards. But large Dk differences between layers is undesirable.

Is the woven glass reinforcement pattern visible in Rogers 6202 laminates?

No, the distribued microfiber glass threads in 6202 are not visibly discernible unlike some other woven glass reinforced laminates that show a fabric weave pattern.