Rogers RO4350B vs Megtron 6: Which High-Frequency Laminate for Your Next Design?

30-Second Decision

Bottom line: If your design is a dedicated RF front-end (antenna feed, LNA, filter) at 2-20 GHz with fewer than 10 layers, choose RO4350B. If you need a high-layer-count mixed-signal board with both high-speed digital (PCIe Gen5, 112G SerDes) and moderate RF performance, choose Megtron 6.

Electrical Performance: The Numbers That Matter

Dielectric Constant (Dk) Stability

RO4350B maintains Dk within +/-0.05 from 1 to 40 GHz. Megtron 6 shows more variation above 20 GHz, with Dk drift of +/-0.08. For impedance-controlled designs where tight tolerance matters (antenna matching networks, filter tuning), this stability directly affects yield.

Practical impact: A 50-ohm microstrip on RO4350B stays within +/-2 ohms across a 10 GHz bandwidth. The same trace on Megtron 6 may vary +/-4 ohms — acceptable for digital, problematic for RF.

Loss Tangent (Df) and Insertion Loss

At 10 GHz over a 100mm trace:

• RO4350B: 0.28 dB insertion loss
• Megtron 6: 0.34 dB insertion loss
• Standard FR-4 (Dk ~4.4, Df ~0.02): 1.5 dB insertion loss

The 0.06 dB difference between RO4350B and Megtron 6 becomes significant in:

• Phased array feeds with 16+ elements (cumulative loss budget)
• Multi-stage filter designs where every 0.1 dB matters
• Long backplane channels above 25 Gbps NRZ

For PCIe Gen5 (32 GT/s) over 200mm, both materials deliver adequate eye opening. The difference only surfaces at 112G PAM4 channel lengths above 150mm.

Fabrication and Processability

This is where Megtron 6 pulls ahead decisively.

Drilling

RO4350B contains ceramic filler that accelerates drill bit wear. Production runs above 500 panels require more frequent bit changes, adding 5-10% to drilling cost.

Lamination

RO4350B requires:

• Specific bonding films (RO4450F or low-flow prepregs)
• Tighter temperature ramps (2C/min vs 3-4C/min standard)
• Not all fab shops have qualified RO4350B processes

Megtron 6 laminates with standard FR-4 prepregs and press cycles. Any shop running high-Tg FR-4 can process Megtron 6 without qualification.

RF PCB EXPERTISE

Not Sure Which Material Fits Your Design?

Our engineers work with both RO4350B and Megtron 6 daily. Upload your stackup for a material recommendation based on your actual frequency plan.

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Hybrid Stackup: Using Both Materials Together

For complex systems (phased array radar, 5G base station), the optimal approach is often a hybrid stackup:

• RF layers (antenna/feed): RO4350B cores for antenna elements and RF signal routing
• Digital layers (FPGA, SerDes): Megtron 6 for high-speed digital interconnects
• Power layers: Standard high-Tg FR-4 (cost optimization)

Hybrid stackup example (10-layer):

L1  — RO4350B — Antenna/RF signals
L2  — GND (reference)
L3  — Megtron 6 — High-speed digital
L4  — GND
L5  — FR-4 — Power
L6  — FR-4 — Power  
L7  — GND
L8  — Megtron 6 — High-speed digital
L9  — GND (reference)
L10 — RO4350B — RF signals

Challenges of hybrid:

• CTE mismatch between materials creates stress during thermal cycling
• Requires qualification of bonding film between dissimilar materials
• Limited to shops experienced with mixed-dielectric builds
• Add 20-30% to cost vs single-material stackup

AtlasPCB regularly fabricates hybrid Rogers/FR-4 stackups with controlled CTE transitions.

MIXED-DIELECTRIC BUILDS

Hybrid Stackup? We Build Them Weekly.

Rogers + Megtron + FR-4 in a single board. Our lamination team has qualified 40+ hybrid material combinations.

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Application Decision Matrix

PROTOTYPE FAST-TRACK

Rogers and Megtron In Stock

We stock RO4350B (20/30/60mil) and Megtron 6 cores. Prototype in 7-10 days for RF boards.

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Cost Comparison: Real-World Pricing

For a typical 6-layer, 100x100mm, 10-piece prototype run:

Volume pricing at 1000 pcs (same board):

• Standard FR-4: $8-12/board
• Megtron 6: $14-22/board
• RO4350B: $28-45/board

The 2-3x premium for Rogers only makes sense when electrical performance requirements genuinely demand it. Many designers over-specify material — using RO4350B where Megtron 6 suffices wastes 40-60% of material budget.

Standards and Specifications

ATLASPCB

Ready to Compare Quotes?

Upload your design — we quote both RO4350B and Megtron 6 options so you can compare cost vs performance with real numbers.

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Related Reading:

• High-Frequency PCB Design Best Practices
• PCB Hybrid Stackup: Rogers + FR-4 Design Guide
• Megtron 6 vs Rogers 4350B Detailed Laminate Comparison
• Signal Integrity in PCB Design