RO4350B PCB: Material Guide, Dielectric Constant, Data Sheet & Applications
September 3, 2025
With over 18,000 customers worldwide relying on high-frequency PCB solutions, engineers designing RF circuits for frequencies above 6 GHz face critical challenges: signal loss, impedance instability, and thermal management issues that standard FR4 materials simply cannot address effectively.
Rogers RO4350B emerges as the optimal solution, offering a unique balance of electrical performance and manufacturability. With its precisely controlled dielectric constant of 3.48 ± 0.05 and exceptionally low loss tangent of 0.0037 at 10 GHz, RO4350B enables engineers to achieve stringent performance requirements for 5G infrastructure, automotive radar systems, and aerospace applications while maintaining compatibility with standard PCB manufacturing processes.
Modern high-frequency circuits demand materials that can maintain signal integrity under harsh conditions. RO4350B addresses the limitations of FR4 and provides an industry-standard balance of performance, manufacturability, and cost.
| Parameter | RO4350B / High-Frequency Requirement | Standard FR4 Limitation |
|---|---|---|
| Frequency Range | Stable performance up to 40 GHz | Severe degradation above 1 GHz |
| Dielectric Constant (Dk) | 3.48 ± 0.05 (stable) | Variation ±10–15% with temp/frequency |
| Loss Tangent @ 10 GHz | 0.0037 | 0.015–0.025 |
| Propagation Delay | ≤0.2 ps/inch variation | Highly inconsistent |
| Moisture Absorption | Low, stable | High, dielectric properties shift |
| Glass Weave Effect | Minimal | Causes impedance variation |
RO4350B’s engineered composition addresses the critical performance gaps found in conventional PCB materials through precisely controlled dielectric properties and enhanced thermal characteristics.
Below are properties of the RO4350B that directly address thermal stability and signal integrity challenges in telecom, radar, and aerospace.
| Property | Value | Benefit |
|---|---|---|
| Dielectric Constant (Dk) | 3.48 ± 0.05 | Precise impedance control |
| Loss Tangent @ 10 GHz | 0.0037 | Low signal attenuation |
| Moisture Absorption | 0.06% | Stable electrical properties |
| Z-axis CTE | 32 ppm/°C | Copper-compatible, reduces via stress |
| Thermal Conductivity | 0.69 W/m/K | Effective heat dissipation |
| Operating Temp Range | -55°C to +288°C | Extreme environment reliability |
| Flexural Strength | 275 MPa | Mechanical robustness |
| Peel Strength | 1.4 N/mm | Strong copper adhesion |
Unlike PTFE-based materials that require specialized processing techniques, RO4350B can be fabricated using standard FR4 manufacturing processes. This compatibility reduces manufacturing costs and lead times while maintaining the electrical performance advantages of high-frequency materials.
The material’s excellent drill quality eliminates the need for specialized drill bits or modified drilling parameters. Via formation proceeds smoothly without delamination or resin smearing issues common with other high-frequency substrates.
Choosing between RO4350B and RO4003C depends on balancing performance, cost, and processing needs. Each material excels in different high-frequency applications, and understanding these trade-offs guides the right selection.
| Factor | RO4350B | RO4003C |
|---|---|---|
| Dielectric Constant (Dk) | 3.48 | 3.38 |
| Loss Tangent @ 10 GHz | 0.0037 | 0.0027 |
| Processing | Standard FR4 compatible | Requires specialized processing |
| Cost | Lower | Higher |
| Frequency Suitability | Up to 40 GHz | >40 GHz ultra-low loss |
| Applications | Automotive radar, 5G, cost-sensitive production | Satellite comms, ultra-high frequency |
Use RO4350B when cost and manufacturability matter, while RO4003C is recommended for extreme low-loss needs at >40 GHz.
Specific applications across telecommunications, automotive, aerospace, and digital systems require RO4350B’s unique combination of electrical performance and environmental reliability.
| Application | Requirements | Why RO4350B Fits |
|---|---|---|
| 5G Infrastructure | 24–43 GHz, beamforming, low-loss | Stable Dk, low loss tangent |
| Automotive Radar | 24/77 GHz, -40°C to +85°C | Low CTE, thermal reliability |
| Aerospace | Harsh environments, wide temperature range | Mechanical strength, stable performance |
| High-Speed Digital | Edge rates <100 ps, tight timing | Stable Dk reduces skew, ensures timing |
Comprehensive performance analysis reveals significant advantages of RO4350B over standard materials while highlighting strategic trade-offs with other premium substrates.
| Material | Dielectric Constant (Dk) | Loss Tangent @ 10 GHz | Processing | Cost | Suitable Applications |
|---|---|---|---|---|---|
| FR4 | 4.2–4.8 (unstable) | 0.015–0.025 | Standard | Low | Consumer electronics (<1 GHz) |
| RO4350B | 3.48 ± 0.05 | 0.0037 | Standard FR4 compatible | Medium | 5G, automotive radar, aerospace |
| RO4003C | 3.38 | 0.0027 | Specialized | Medium-high | Satellite, >40 GHz |
| RO4533 | 3.0 | 0.0015 | Specialized | High | Ultra-low loss RF |
| RO4835 | 3.33 | ~0.003 | Specialized | High | Specific impedance-critical designs |
For high-volume applications such as automotive radar and 5G infrastructure, RO4350B’s processing advantages and material cost benefits can result in substantial total cost reduction compared to speciality PTFE materials.
RO4350B’s compatibility with standard PCB manufacturing processes eliminates many fabrication challenges while maintaining the performance advantages of high-frequency materials.
RO4350B’s homogeneous construction eliminates the delamination issues common with PTFE-based materials during drilling operations. Standard carbide drill bits perform effectively without requiring specialized cutting tools or modified drilling parameters.
RO4350B laminates easily with standard FR4 prepregs, enabling hybrid stack-ups that optimize cost and performance. The material’s CTE compatibility with copper ensures reliable via connections through temperature cycling.
Press cycles follow standard parameters (375°F, 400 psi, 90 minutes), eliminating the need for specialized lamination equipment.
All standard surface finishes are compatible with RO4350B, including HASL, ENIG, OSP, and immersion silver. The material’s thermal stability accommodates lead-free soldering temperatures without degradation of electrical properties.
Achieving optimal performance with RO4350B requires careful attention to impedance control, thermal management, and design for manufacturability principles.
Achieving precise impedance control with RO4350B requires careful attention to stack-up design and trace geometry. The material’s stable dielectric constant simplifies impedance calculations and reduces the need for test coupons to verify target values.
For differential pairs, maintain tight coupling by minimizing the separation between traces while ensuring adequate clearance to adjacent signals. Via transitions require careful design to minimize discontinuities. Back-drilling long vias removes unused via stubs that can cause reflections at high frequencies.
While RO4350B provides adequate thermal conductivity for most applications, high-power circuits may require additional thermal management techniques. Thermal vias connecting power components to ground planes improve heat dissipation and reduce component temperatures.
Design for manufacturability principles apply equally to RO4350B designs, but the material’s processing advantages simplify several aspects. Standard via sizes and spacing rules can be used without concern for drilling-related yield issues.
KINGBROTHER’s specialized expertise, Rogers partnership, and advanced manufacturing capabilities deliver reliable RO4350B solutions from prototype through high-volume production.
KINGBROTHER’s 28 years of expertise in high-frequency PCB manufacturing provides the foundation for reliable RO4350B production. Serving over 18,000 customers worldwide through 5 design centers and 4 manufacturing bases, our advanced manufacturing capabilities include precision drilling systems capable of 0.06mm laser-drilled vias and impedance control tolerances of ±5% for prototyping and ±10% for production.
Our technical capabilities extend to complex multilayer constructions with up to 68 layers in prototyping and 32 layers in production. With over 1,000 customers maintaining 10+ year relationships, our temperature and humidity-controlled manufacturing environments ensure consistent material properties throughout the production process.
Every RO4350B PCB undergoes comprehensive electrical testing, including impedance verification, continuity testing, and isolation measurements. Our quality control procedures include cross-sectional analysis to verify via formation quality and layer registration accuracy.
As an authorized Rogers Corporation fabricator with 28+ years of experience, KINGBROTHER maintains direct access to technical support and material certifications required for critical applications. Our partnership ensures authentic material sourcing and access to the latest processing guidelines and design recommendations.
With no minimum order quantity (MOQ) requirements and a proven track record serving customers across communication, automotive, industrial control, AI, and medical equipment sectors, our global supply chain management ensures reliable RO4350B material availability even during supply constraints.
RO4350B PCB material delivers the optimal balance of high-frequency performance and manufacturability for 5G infrastructure, automotive radar, and aerospace applications. With its stable dielectric constant of 3.48 ± 0.05, low loss tangent of 0.0037 at 10 GHz, and compatibility with standard PCB processes, RO4350B enables predictable performance while reducing manufacturing costs compared to specialized PTFE materials. KINGBROTHER’s 28+ years of expertise, Rogers partnership, and advanced capabilities ensure reliable RO4350B manufacturing with comprehensive support from design optimization to production.
Contact KINGBROTHER today to discuss your RO4350B PCB requirements and accelerate your high-frequency design success.
RO4350B (Dk 3.48, loss tangent 0.0037) offers standard FR4 processing compatibility, reducing costs and lead times. RO4003C (Dk 3.38, loss tangent 0.0027) provides slightly lower loss but requires specialized processing. Choose RO4350B for cost-sensitive applications up to 40 GHz; select RO4003C for ultra-low loss requirements above 40 GHz.
RO4350B balances performance and manufacturability for mainstream applications. RO4533 offers ultra-low loss (0.0015) but needs specialized processing. RO4835 provides a lower Dk (3.33) for specific impedance requirements. RO4350B remains optimal for standard high-frequency applications prioritizing processing ease.
RO4350B maintains ±2% dielectric stability versus FR4’s 15-20% variation. Loss tangent at 10 GHz is 0.0037 versus FR4’s 0.015-0.025, providing 4-7 times lower signal attenuation. RO4350B is essential for applications above 2 GHz requiring signal integrity.
RO4350B excels in 5G mmWave beamforming networks, power amplifiers, and antenna arrays for 24-29 GHz and 37-43 GHz bands. Base stations, small cells, and customer premise equipment benefit from its stable dielectric properties and thermal reliability in outdoor installations.
