Complete technical reference for designers working with Rogers RO4350B — covering dielectric constant, impedance design, White Tin finish, manufacturing tolerances, and high-frequency applications from 1 GHz to 77 GHz.
RO4350B is a hydrocarbon ceramic laminate engineered for stable Dk across a wide frequency range — critical for predictable impedance in high-frequency designs above 500 MHz.
| Property | Value | Unit | Test Condition | Standard |
|---|---|---|---|---|
| Dielectric Constant (Dk) | 3.48 ±0.05 | — | 10 GHz / 23°C | IPC-TM-650 2.5.5.5 |
| Dissipation Factor (Df) | 0.0037 | — | 10 GHz / 23°C | IPC-TM-650 2.5.5.5 |
| Thermal Coeff. of Dk | +50 | ppm/°C | −50 to +150°C | IPC-TM-650 2.5.5.5 |
| Dimensional Stability | <0.5 / <0.5 | mm/m | after etch x/y | IPC-TM-650 2.4.39 |
| Coefficient of Thermal Expansion (x) | 14 | ppm/°C | −55 to +288°C | IPC-TM-650 2.4.41 |
| Coefficient of Thermal Expansion (y) | 16 | ppm/°C | −55 to +288°C | IPC-TM-650 2.4.41 |
| Coefficient of Thermal Expansion (z) | 50 | ppm/°C | −55 to +288°C | IPC-TM-650 2.4.41 |
| Thermal Conductivity | 0.69 | W/(m·K) | — | ASTM E1461 |
| Glass Transition Temperature (Tg) | >280 | °C | TMA | IPC-TM-650 2.4.24 |
| Decomposition Temperature (Td) | 390 | °C | TGA | IPC-TM-650 2.4.24.6 |
| Peel Strength (1 oz Cu) | 1.1 | N/mm | after thermal stress | IPC-TM-650 2.4.8 |
| Volume Resistivity | 1.7×10⁹ | MΩ·cm | IPC-TM-650 2.5.17 | — |
| Surface Resistivity | 4.2×10⁹ | MΩ/sq | IPC-TM-650 2.5.17 | — |
| Dielectric Breakdown | 31.2 | kV/mm | ASTM D149 | — |
| Parameter | RO4350B | RO4003C | FR4 (standard) | PTFE (Rogers RT/duroid) |
|---|---|---|---|---|
| Dk @ 10 GHz | 3.48 ±0.05 | 3.55 ±0.05 | 4.2–4.8 (variable) | 2.2–2.94 |
| Df @ 10 GHz | 0.0037 | 0.0027 | 0.018–0.025 | 0.0009–0.002 |
| Tg | >280°C | >280°C | 130–170°C | N/A (thermoset) |
| CTE z-axis | 50 ppm/°C | 46 ppm/°C | 70 ppm/°C | 24 ppm/°C |
| Dk Stability vs Freq | Excellent | Excellent | Poor | Good |
| Dk Stability vs Temp | Excellent | Excellent | Poor | Good |
| Water Absorption | 0.06% | 0.06% | 0.10% | <0.02% |
| Standard PCB Process | Yes (like FR4) | Yes (like FR4) | Yes | No (special process) |
| Relative Cost (2-layer) | 3–5×FR4 | 3–5×FR4 | Base | 8–15×FR4 |
| Max Freq. Recommendation | 77 GHz+ | 77 GHz+ | ≤1 GHz | 100+ GHz |
| Core Thickness | Tolerance | Common Copper Weight | Typical Z0 (50Ω microstrip) | Application Notes |
|---|---|---|---|---|
| 0.101 mm (4 mil) | ±0.013 mm | 0.5 oz, 1 oz | ~1.3 mm trace | mmWave, 60–77 GHz |
| 0.168 mm (6.6 mil) | ±0.013 mm | 0.5 oz, 1 oz | ~2.2 mm trace | 5G sub-6 GHz to 30 GHz |
| 0.254 mm (10 mil) | ±0.025 mm | 0.5 oz, 1 oz, 2 oz | ~3.4 mm trace | Most popular – 5–20 GHz |
| 0.508 mm (20 mil) | ±0.038 mm | 1 oz, 2 oz | ~6.8 mm trace | Power amplifiers, 1–10 GHz |
| 0.762 mm (30 mil) | ±0.064 mm | 1 oz, 2 oz | ~10.2 mm trace | High-power RF, base station |
| 1.524 mm (60 mil) | ±0.099 mm | 1 oz, 2 oz | ~20.5 mm trace | Low-freq RF, hybrid boards |
Calculate microstrip and stripline characteristic impedance using RO4350B's measured Dk of 3.48. Results are based on the IPC-2141A and Hammerstad–Jensen models.
Dk locked to 3.48 (Rogers RO4350B @ 10 GHz). Adjust trace geometry to find 50Ω.
RO4350B processes on standard FR4 equipment — no special tooling required. These guidelines ensure yield and dimensional accuracy for RF designs.
Immersion Tin (White Tin) is a leading surface finish choice for Rogers Ro4350b PCB in RF and microwave applications. The flat, co-planar surface preserves trace geometry — critical when microstrip impedance depends on copper edge definition.
Unlike HASL, which deposits solder unevenly and alters effective trace width, White Tin deposits uniformly to 0.8–1.2 μm. This preserves the impedance calculation precision that makes RO4350B valuable in the first place.
RO4350B is the substrate of choice across commercial and defense RF systems wherever FR4's lossy, unstable dielectric would degrade signal integrity.
RO4350B costs 3–6× more than FR4 for equivalent layers — but delivers performance that FR4 simply cannot match above 1 GHz. Here's what drives the price.
Ready to manufacture your Rogers Ro4350b PCB design? PCBSync specializes in Rogers laminates with certified impedance control.
Get a Quote for Rogers Ro4350b PCB →Everything an RF engineer needs to confidently specify and design with RO4350B.
Rogers RO4350B is a proprietary thermoset hydrocarbon ceramic laminate from Rogers Corporation, widely regarded as the industry standard for commercial RF and microwave PCB designs. It is part of the RO4000 series — a family of materials engineered to process on standard FR4 equipment while delivering performance approaching PTFE at a fraction of the complexity and cost.
The "B" suffix denotes the bonded version, which includes glass reinforcement for improved mechanical strength compared to the unreinforced RO4350. The glass-reinforced construction enables tighter dimensional tolerances and better drill registration in multilayer builds.
The dielectric constant (Dk) of 3.48 at 10 GHz determines physical trace dimensions for a given impedance. A lower Dk than FR4 (~4.5) means wider traces for the same impedance — easier to manufacture precisely and less sensitive to etch variation. More importantly, RO4350B's Dk is stable from 1 GHz to 40 GHz, with only a shallow frequency dispersion, unlike FR4 where Dk can vary by 0.3–0.8 across the same range.
This stability directly translates to predictable group delay and phase linearity — essential for wideband radar waveforms, broadband LNAs, and Doherty power amplifier matching networks where phase tracking across bandwidth is a hard design constraint.
The dissipation factor of 0.0037 at 10 GHz is approximately 5–6× lower than standard FR4 (0.018–0.025). In practical terms, a 100mm microstrip line at 10 GHz on RO4350B incurs roughly 0.4–0.6 dB/cm less dielectric loss than the same line on FR4. For a 5 GHz filter with 20mm of transmission line, the board material alone contributes several dB of the loss budget — a difference that dominates system noise figure and output power in sensitive receivers and power-limited transmitters.
Both materials share the same substrate chemistry. RO4003C has a slightly lower Df (0.0027 vs 0.0037) and nearly identical Dk (3.55 vs 3.48) — choose it when insertion loss is the dominant constraint above 20 GHz, such as V-band backhaul or mmWave imaging.
RO4350B is the broader choice: it is certified UL 94 V-0 (flame retardant) out of the box without additive treatments, which simplifies compliance for commercial equipment. It also has a slightly lower Dk, translating to marginally wider traces — more process margin for manufacturers. For most 5G, automotive radar, and Ku-band satellite designs below 40 GHz, RO4350B is the default.
For products with both an RF front-end and a digital processing board, hybrid stackups combining RO4350B RF layers with FR4 digital layers are common. The key requirement is bondply compatibility: Rogers RO4450F prepreg is specifically formulated to bond RO4350B cores in multilayer constructions, offering Dk of 3.52 (close to 3.48) to maintain impedance consistency across the bonding interface.
In hybrid builds, keep all impedance-critical RF signal layers within the RO4350B cores. Digital layers can use standard FR4 prepreg and cores, provided that via stubs are managed (back-drilling recommended above 10 GHz) and cross-plane coupling between RF and digital layers is mitigated by proper ground plane arrangement.
The combination of Rogers Ro4350b PCB with White Tin (Immersion Tin) surface finish is a proven, cost-effective solution for RF and microwave boards. White Tin delivers the flat, co-planar surface geometry that preserves microstrip trace width — directly supporting the impedance accuracy that makes RO4350B worth specifying. PCBSync offers Rogers Ro4350b PCB with White Tin finish with IPC-4554 compliance and controlled impedance verification.