RO4350B Material Properties
| Property | RO4350B | RO4003C (comparison) |
|---|
| Relative permittivity εr (10 GHz) | 3.66 ± 0.05 | 3.55 ± 0.05 |
| Loss tangent tan δ (10 GHz) | 0.0037 | 0.0027 |
| Temperature coefficient of εr | +50 ppm/°C | +40 ppm/°C |
| Halogen-free | Yes | No (standard) |
| CAF resistance | Excellent | Good |
| UL 94 flame rating | V-0 | V-0 |
| Standard PCB process | Yes | Yes |
50 Ω Microstrip Width on RO4350B
| Substrate H | W for 50 Ω | εe | λ/4 at 5 GHz | λ/4 at 24 GHz |
|---|
| 0.254 mm (10 mil) | 0.56 mm | 2.88 | 8.83 mm | 1.84 mm |
| 0.508 mm (20 mil) | 1.13 mm | 2.89 | 8.81 mm | 1.84 mm |
| 1.524 mm (60 mil) | 3.38 mm | 2.90 | 8.78 mm | 1.83 mm |
Insertion Loss Comparison
| Frequency | RO4350B | RO4003C | FR4 |
|---|
| 2.4 GHz (100 mm) | ~0.6 dB | ~0.5 dB | ~1.7 dB |
| 5 GHz (100 mm) | ~1.1 dB | ~0.9 dB | ~3.5 dB |
| 10 GHz (100 mm) | ~2.0 dB | ~1.5 dB | ~7.0 dB |
| 24 GHz (100 mm) | ~5.5 dB | ~4.0 dB | N/A |
When to Choose RO4350B vs RO4003C
- Choose RO4350B when: halogen-free is required (RoHS compliance, automotive), CAF resistance needed for high-humidity environments, slightly higher εr (3.66 vs 3.55) helps with more compact line widths
- Choose RO4003C when: lowest possible loss is critical (higher Q filter designs), mmWave above 20 GHz where 0.001 tan δ difference matters
RF View Microstrip Calculator: Enter εr=3.66 for RO4350B to compute 50 Ω trace widths, guided wavelengths, and quarter-wave lengths at your operating frequency. Offline in the Utilities tab.
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