# Rogers RO4350B PCB Laminate _Published: 2026-04-18_ Table of Contents Toggle - What Is RO4350B PCB Material? - RO4350B Datasheet Overview - Key Features of RO4350B PCB Material - What Is the Dielectric Constant of RO4350B? - Applications of RO4350B PCB Material - RO4350B vs RO4003C vs FR‑4 - How to Choose RO4350B for Your PCB Design? - Frequently Asked Questions - Get RO4350B PCB Support **[RO4350B PCB material](https://www.bestpcbs.com/blog/2025/07/ro4350b-pcb-material-why-choose-it-for-high-frequency-pcb/)** is one of the most widely used laminates for high-frequency circuit design, especially in RF, microwave, and high-speed digital applications. As signal frequencies continue to increase in modern electronics—such as 5G communication, automotive radar, and satellite systems—the limitations of standard FR4 materials become more evident. Engineers increasingly require materials that can maintain **low signal loss, stable dielectric performance, and reliable thermal behavior**. ![](https://www.bestpcbs.com/blog/wp-content/uploads/2026/04/6b77e95a9ff84d8880d968bf3dd5da4c.png) **Rogers RO4350B PCB Laminate** ## What Is RO4350B PCB Material? [RO4350B PCB](https://www.bestpcbs.com/blog/2025/07/ro4350b-pcb-material-why-choose-it-for-high-frequency-pcb/) material is a **hydrocarbon ceramic-filled laminate** developed by Rogers Corporation, specifically engineered for high-frequency and RF circuit applications. Unlike standard FR4 materials, RO4350B is designed to deliver: - Low dielectric loss for minimal signal attenuation - Stable dielectric constant (Dk) across wide frequency ranges - High thermal reliability under lead-free assembly - FR4-compatible processing, reducing manufacturing complexity This combination allows engineers to design **RF, microwave, and [high-speed PCBs](https://www.bestpcbs.com/products/high-speed-pcb.htm)** with predictable electrical performance while maintaining scalable production. ## RO4350B Datasheet Overview Category Property RO4350B Typical Value Engineering Meaning Thermal Tg (DSC/TMA) >280 °C Excellent thermal stability, lead‑free safe Td (5% weight loss) ≥390 °C High thermal decomposition resistance T260 >30 min Strong resistance to delamination T288 >15 min Withstands high‑temp reflow CTE (X/Y) 10–12 ppm/°C Matches copper, minimal warpage CTE (Z‑axis, 280 °C and high Td ensure stability during multiple lead‑free reflows. Low CTE in X/Y/Z axes reduces thermal stress, greatly improving via and board reliability under thermal cycling. **3. Easy Processing Like FR‑4** Unlike PTFE materials, RO4350B uses standard drilling, plating, and lamination. It supports mixed stackups with FR‑4, cutting cost while keeping RF performance. **4. Low Moisture & High Environmental Stability** Water absorption ≤0.06% maintains consistent electrical properties in high humidity. V‑0 rating and robust mechanical strength suit automotive, industrial, and aerospace environments. **5. Versatile Multilayer Compatibility** Paired with RO4450B prepreg for multilayer RF boards. Supports hybrid designs: RO4350B for RF layers, FR‑4 for digital/power layers to balance performance and BOM cost. ## What Is the Dielectric Constant of RO4350B? The **[RO4350B dielectric constant](https://www.bestpcbs.com/blog/2026/04/rogers-ro4350b-pcb-laminate/)** is: - 3.48 ± 0.05 at 10 GHz - ~3.66 for design calculations This value remains **stable from MHz to tens of GHz**, which is critical for impedance-controlled RF designs. **Why This Matters** A stable Dk enables: - Accurate 50Ω transmission line design - Reliable RF matching networks - Consistent signal timing and phase control In contrast, FR4 materials show significant variation with frequency, which leads to impedance drift. ## Applications of RO4350B PCB Material - 5G base stations, antennas, microwave filters - Automotive radar (24 GHz / 77 GHz ADAS) - RF power amplifiers, couplers, dividers - Satellite communications, aerospace radar - High‑speed backplanes and interconnects - WLAN, RFID, point‑to‑point radio - Test & measurement instrumentation ## RO4350B vs RO4003C vs FR‑4 Property RO4350B RO4003C Standard FR‑4 Dk @10 GHz 3.48 3.38 ~4.4 Df @10 GHz 0.0037 0.0027 0.020–0.030 Tg >280 °C >280 °C 130–150 °C Thermal Conductivity 0.69 0.64 ~0.25 FR‑4 Process Compatibility Yes Yes N/A Flame Retardant V‑0 Non‑V‑0 V‑0 Max Frequency Up to 77 GHz+ Up to 40 GHz ~3 GHz Cost Medium Medium‑High Low Best For General RF, 5G, automotive radar Ultra‑low‑loss RF Low‑speed digital ## How to Choose RO4350B for Your PCB Design? Choose RO4350B if: - Your design involves RF, microwave, or high‑speed signals >3 GHz - You need stable impedance and low insertion loss - You want FR‑4‑like processing but better performance - Applications: automotive radar, 5G, aerospace, test instruments - You need V‑0 flame retardant for commercial/industrial use Consider alternatives if: - Extreme low loss → RO4003C - Pure cost priority → FR‑4 / S1000H - Non‑RF low‑speed digital → standard high‑Tg FR‑4 ## Frequently Asked Questions **1. What is the difference between RO4350B and FR-4?** While both can be processed using standard fabrication methods, they differ significantly in electrical performance. **RO4350B** is a hydrocarbon/ceramic laminate designed for high-frequency applications (up to 77 GHz), offering a stable dielectric constant (Dk) and much lower signal loss (Loss Tangent of **0.0037**) compared to **FR-4** (Loss Tangent of **~0.015–0.025**). FR-4 typically struggles with signal integrity above 2–3 GHz, whereas RO4350B maintains its properties into the millimeter-wave range. **2. Is RO4350B compatible with standard lead-free soldering?** Yes. RO4350B has a high glass transition temperature (**Tg > 280°C**) and a decomposition temperature (**Td**) of **390°C**. This makes it fully compatible with automated assembly and lead-free reflow soldering processes, which typically peak around 260°C. Its low Z-axis coefficient of thermal expansion (**32 ppm/°C**) also ensures that plated through-holes (PTH) remain reliable during thermal cycling. **3. What is the Dielectric Constant (Dk) of Rogers 4350B?** The standard design Dielectric Constant for RO4350B is **3.48 ± 0.05** at 10 GHz. This value is exceptionally stable across a wide frequency range, which is critical for designing controlled impedance transmission lines and wideband matching networks. **Note:** For very thin materials (e.g., 0.004″), the Dk specification may shift slightly to 3.36. **4. How does RO4350B compare to RO4003C?** Both belong to the Rogers 4000 series, but the primary difference is the flame retardancy rating. **RO4350B** is **UL 94 V-0** rated, making it the industry standard for commercial and active devices where fire safety certification is required. **RO4003C** is not UL 94 V-0 rated, though it offers a slightly lower loss tangent (**0.0027**) and a slightly lower Dk (**3.38**), making it preferable for specific passive applications where every fraction of a decibel counts. **5. Does RO4350B require special plasma etching for through-hole plating?** No. Unlike PTFE-based materials (like the Rogers 5000 or 6000 series), RO4350B is a **thermoset hydrocarbon** laminate. This means it can be processed using standard epoxy/glass (FR-4) techniques. It does **not** require specialized via preparation, such as sodium naphthenate or plasma etching, which significantly reduces manufacturing costs and lead times. ## Get RO4350B PCB Support If your project involves RF or high-speed PCB design, selecting the right material is critical. We’re happy to support you with: - Stack-up design - RF PCB optimization - Fast PCB & PCBA production 📧 sales@bestpcbs.com Feel free to reach out — your project will be supported by engineers who understand real RF challenges.