Rogers 4350 PCB laminate compared to Panasonic Megtron6 PCB material

PCB material selection is a crucial component in the performance of a circuit assembly.  In the past, typically FR4 was specified. But, with high-speed designs, the use of the correct laminate is critical. The use of a material with a lower dielectric constant (Dk) is advisable and preferred. This not only ensures the best signal performance, but it will also minimize any signal distortion or phase jitter of the signal.

Choosing the material for your PCB must take into consideration these factors:

  • Mechanical strength
  • Thermal characteristics
  • Electromagnetic loss
  • Environmental stability of the material in varying humidity and temperature settings
  • RF-power handling capability
  • Compatibility and use in hybrid constructions
  • Cost

Rogers RO4350B Laminates

The Rogers RO4350B laminates provide a low dissipation factor (Df), which boosts the power delivered and therefore enables high-power applications. Also, their low dielectric constant (Dk) permit rapid signal propagation. RO4350B laminates do not call for the special through-hole treatments or handling procedures as PTFE based materials. These materials are UL 94 V-0 rated for active devices and high power RF designs.

Summary of features:

  • Dk of 3.48 +/- 0.05
  • Dissipation factor of 0.0037 at 10 GHz
  • Low Z-axis coefficient of thermal expansion at 32 ppm/°C


  • Processes like FR-4 at lower fabrication cost
  • Competitively priced
  • Excellent dimensional stability

Standard Thickness:

  • 0.004” ( not available in panel sizes larger than 24”x18”)
  • 0.0066”
  • 0.010”
  • 0.0133”
  • 0.0166”
  • 0.020”
  • 0.030”

Panasonic MEGTRON6 – R-5775 Laminates

The MEGTRON6 laminates are high speed, ultra-low loss materials with impressive HDI and thermal performance

Summary of features:

  • Dk 3.4, Df 0.004@12GHz
  • Tg (DMA) 185°C
  • T288(with copper) >120min.

    Find out the main differences between 2 of the most commonly used high-frequency, high-speed laminates; Rogers 4350B and Panasonic Megtron 6.


    PropertyRogers RO4350BConditionTest MethodPanasonic R-5775(N) – Low Dk glass cloth versionPanasonic R-5775 – Normal glass clothTest Method
    Dielectric Constant (Dk)3.48 ± 0.0510 GHz/23°CIPC-TM-650
    Clamped Stripline

    3.40 (@1 GHZ)

    3.35 (@12 GHZ)

    3.6 (@12 GHZ)IPC-TM-650
    Dissipation Factor tan (Df)0.0037
    10 GHz/23°C
    2.5 GHz/23°C

    0.002 (@1 GHZ)

    0.004 (@12 GHZ)

    0.002 (@1 GHZ)

    0.004 (@12 GHZ)

    Thermal Coefficient+50 ppm/°C-50°C to 150°CIPC-TM-650 ppm/°C45 ppm/°CIPC TM-650 2.4.24
    Volume Resistivity1.2 X 1010 MΩ•cmCOND AIPC-TM-650 X 109MΩ•cm1 X 109MΩ•cmIPC TM-650
    Surface Resistivity5.7 X 108COND AIPC-TM-650 X 1081 X 108IPC TM-650
    Electrical StrengthZ- axis 31.2 KV/mm0.51mm (0.020”)IPC-TM-650
    Tensile ModulusX- 16,767 MPa
    X- 14,153 MPa
    RTASTM D638    18,000    19,000JIS C 6481
    Tensile StrengthX- 203 MPa
    Y- 130 MPa
    RTASTM D638
    Flexural Strength255 MPaIPC-TM-650 2.4.4
    Dimensional Stability<0.5 mm/mafter etch
    IPC-TM-650 2.4.39A
    Coefficient of Thermal Expansion(X)10 ppm/°C-55 to 288°CIPC-TM-650 2.4.4114-16 @ 260°C14-16 @ 260°CIPC-TM-650
    Coefficient of Thermal Expansion(Y)12 ppm/°C-55 to 288°CIPC-TM-650 2.4.4114-16 @ 260°C14-16 @ 260°CIPC-TM-650
    Coefficient of Thermal Expansion(Z)32 ppm/°C-55 to 288°CIPC-TM-650 2.4.4145 @ 260°C45 @ 260°CIPC-TM-650
    Tg>280 °C TMAAIPC-TM-650
    Td390 °C TGAASTM D3850410410TGA
    Thermal Conductivity0.69 W/m/°K80°CASTM C518
    Moisture Absorption0.06%48 hrs immersion
    0.060” sample Temperature 50°C
    ASTM D5700.14%0.14%IPC-TM-650
    0.030″ sample
    Density1.86 gm/cm323°CASTM D792
    Copper Peel Strength0.88 N/mmafter solder float 1 oz. EDC FoilIPC-TM-650 kN / m0.8 kN / mIPC-TM-650
    Flammability94V-0UL 9494V-0UL 94V-0
    Lead-Free Process CompatibleYes
    Time to delamination at 288°C with copper>120 min>120 minIPC-TM-650


    In sum

    As a part of the design process, PCB designers need to specify materials that offer an optimal or near-optimal price-performance ratio. To achieve this task PCB materials need to be researched, analyzed, evaluated, and selected.

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