RF PCB Laminate Material Comparison (Taconic vs. ISOLA vs. Rogers)

PCB Manufacturing

The Importance of choosing the correct RF PCB Material

Selecting the PCB substrate material is a critical performance factor when designing PCBs for RF applications.

The optimal combination of electrical and mechanical attributes is required for complex microwave structures which are mechanically reliable and electrically stable.

An extremely low thermal coefficient of dielectric constant provides the electrical stability sought after by designers of filters, oscillators, and delay line applications.

Taconic, ISOLA, and Rogers all manufacture PCB laminate materials designed for high-performance, high-speed/RF/microwave applications.

RF PCB Material Comparison

Factors to consider when choosing an RF PCB material

A low Z-axis coefficient of thermal expansion (CTE) is necessary for the superior reliability of plated through-holes.

To achieve a narrow range of positional tolerances, it is imperative to match the X and Y coefficient expansion of the PCB substrate to copper.

Increasing surface mount reliability by reducing stress at solder joints and allowing the expansion of the PCB laminate up to the minimum amount of low CTE is a benefit of a material with low tensile modulus.

  • thermal performance
  • low dissipation factor (Df)
  • stable Df characteristics
  • low Z-axis Coefficient of Thermal Expansion (CTE)
  • skew mitigation properties
  • characteristics to improve rise times
  • jitter reduction
  • conductor loss reduction

One of the key characteristics of high-frequency laminate material is the stability of the dissipation factor (Df) since this will tell you how signal losses occur and their distribution across the frequency band of operation.

Also, a stable dielectric constant (Dk) and consequently a stable impedance across the length and width of a substrate is important.

High-frequency laminates display little change in the Dk with variations in temperature over a wide range.

In an RF or microwave circuit, the value of the dielectric constant will impact the PCB’s trace sizes and therefore the size of the PCB. Higher Dk PCB materials can result in smaller PCBs.

The table below displays the key electrical and mechanical attributes of the Taconic, ISOLA, and Rogers for ease of comparison.

PCB Material Comparison table – Part 1 of 5

ManufacturerTaconicTaconicTaconic
ProductTLX-6,7,7,9,0TLY-5RF35
Material TypePTFE / GlassPTFE / GlassPTFE / Glass
Lead-Free Process CompatibleYesYesYes
Halogen FreeNoNoNo
Flammability UL94V-0V-0V-0
Glass Transition Temp Tg
Celcius
Td (Decomposition Temp) by TGA – ºC
Dk 1 GHz
Dk 2-3 GHz3.5 (±0.10)
Dk 10-12 GHz2.45-2.65  (±0.04)2.2  (±0.03)
Df 1 GHz
Df 2-3 GHz0.00120.002
Df 10-12 GHz0.00155 – 0.00210.0009
Moisture Absorption (%)0.02%0.02%0.02%
CTE X-Axis (PPM/ºC) Pre Tg212619
CTE Y-Axis (PPM/ºC) Pre Tg231524
CTE Z-Axis (ppm/ºC) Pre Tg21521764
Material ConsideredRFRFRF
Peel Strength – 1oz (35μm) – N/mm2.13.041.5
T260
T288 – minutes
Flexural strength – N/mm2X – 199
Y – 142		X – 96.1
Y – 89.32		X – 152
Y – 124
Young’s modulus – N/mm2X – 6,757
Y – 8,274		9.65 x 103
Tensile strength – N/mm2X – 245
Y – 190		X – 187
Y – 145
Volume Resistivity – MΩ/cm1.110 x 10101×10101.26×109
Dielectric strength – V45,000106,023
Surface Resistivity – MΩ/cm6.605 x 1081×1081.46×108
Dimensional stability – mm/M-0.038
Thermal Conductivity – W/mK0.14 – 0.220.220.32

PCB Material Comparison table – Part 2 of 5

ManufacturerTaconicTaconicIsola
ProductRF35TCTSM-DS3Astra MT77
Material TypePTFE / GlassPTFE / GlassPPE Blend
Lead Free Process CompatibleYesYesYes
Halogen FreeNoNoNo
Flammability UL94V-0V-0
Glass Transition Temp Tg
Celcius		200
Td (Decomposition Temp) by TGA – Celcius420526360
Dk 1 GHz
Dk 2-3 GHz3
Dk 10-12 GHz3.5 (±0.05)3 (±0.05)3
Df 1 GHz
Df 2-3 GHz0.002
Df 10-12 GHz0.00110.00110.002
Moisture Absorption (%)0.05%0.07%0.10%
CTE X-Axis (PPM/ºC) Pre Tg111012
CTE Y-Axis (PPM/ºC) Pre Tg131612
CTE Z-Axis (ppm/ºC) Pre Tg342350-70
Material ConsideredRFRFRF
Peel Strength – 1oz (35μm) – N/mm1.231.461
T260>60
T288 – minutes>60
Flexural strength – N/mm2X – 88.94
Y – 80.67		X – 81
Y – 51		X – 338
Y – 269
Young’s modulus – N/mm2X – 4,599
Y – 4,392		X – 6,708
Y – 6,784
Tensile strength – N/mm2X – 62.19
Y – 53.37		X – 48
Y – 26		X – 214
Y – 165
Volume Resistivity – MΩ/cm5.19 x 1081.1 x 1071.33 x 107
Dielectric strength – V22,44121,57545,400
Surface Resistivity – MΩ/cm6.42 x 1072.3 x 1061.33 x 105
Dimensional stability – mm/M
Thermal Conductivity – W/mK0.920.650.45

PCB Material Comparison table – Part 3 of 5

ManufacturerRogersRogersRogers
ProductRT/duroid 5870RT/duroid 5880RT/duroid 6002
Material TypePTFE /GlassPTFE / GlassCeramic / PTFE
Lead Free Process CompatibleYesYesYes
Halogen FreeNoNoNo
Flammability UL94V-0V-0V-0
Glass Transition Temp Tg
Celcius
Td (Decomposition Temp) by TGA – Celcius500500500
Dk 1 GHz
Dk 2-3 GHz
Dk 10-12 GHz2.33  (±0.02)2.2  (±0.02)2.94 (±0.04)
Df 1 GHz0.0005 (1MHz)0.0004 (1MHz)
Df 2-3 GHz
Df 10-12 GHz0.00129E-040.001
Moisture Absorption (%)0.02%0.02%0.02%
CTE X-Axis (PPM/ºC) Pre Tg223112
CTE Y-Axis (PPM/ºC) Pre Tg284816
CTE Z-Axis (ppm/ºC) Pre Tg17323724
Material ConsideredRFRFRF
Peel Strength – 1oz (35μm) – N/mm4.85.51.6
T260
T288 – minutes
Flexural strength – N/mm2
Young’s modulus – N/mm2
Tensile strength – N/mm21,300
1,280  (@ 23 ºC)		1,070
860 (@ 23 ºC)		828 (@ 23 ºC)
Volume Resistivity – MΩ/cm2×1072×1071×106
Dielectric strength – V
Surface Resistivity – MΩ/cm2×1073×1071×107
Dimensional stability – mm/M
Thermal Conductivity – W/mK0.22 (@ 80 ºC)0.20 (@ 80 ºC)0.60  (@ 23 ºC)

PCB Material Comparison table – Part 4 of 5

ManufacturerRogersRogersRogers
ProductRT/duroid 6006RT/duroid
6010.2LM		RT/duroid 6202
Material TypeCeramic / PTFECeramic / PTFECeramic / PTFE
Lead Free Process CompatibleYesYesYes
Halogen FreeNoNoNo
Flammability UL94V-0V-0V-0
Glass Transition Temp Tg
Celcius
Td (Decomposition Temp) by TGA – Celcius500500500
Dk 1 GHz
Dk 2-3 GHz
Dk 10-12 GHz6.15 (±0.15)10.2 (±0.25)2.94 ± 0.04
Df 1 GHz
Df 2-3 GHz
Df 10-12 GHz0.00270.00230.002
Moisture Absorption (%)0.05%0.01%0.10%
CTE X-Axis (PPM/ºC) Pre Tg472415
CTE Y-Axis (PPM/ºC) Pre Tg342415
CTE Z-Axis (ppm/ºC) Pre Tg1174730
Material ConsideredRFRFRF
Peel Strength – 1oz (35μm) – N/mm2.52.11.6
T260
T288 – minutes
Flexural strength – N/mm2 X – 2634
Y – 1951		X – 4364
Y – 3751
Young’s modulus – N/mm2X – 627
Y – 517		 X- 931
Y – 559
Tensile strength – N/mm21007
Volume Resistivity – MΩ/cm2×1075×1051×106
Dielectric strength – V
Surface Resistivity – MΩ/cm7×1075×1061×109
Dimensional stability – mm/M
Thermal Conductivity – W/mK0.49 (@ 80ºC)0.86 (@ 80ºC)0.68

PCB Material Comparison table – Part 5 of 5

ManufacturerRogersRogersRogersRogers
ProductRO3210RO3003TMM-3TMM-10
Material TypeCeramic / PTFECeramic / PTFECeramic, hydrocarbon, thermoset polymerCeramic, hydrocarbon, thermoset polymer
Lead Free Process CompatibleYesYesYesYes
Halogen FreeNoNoNoNo
Flammability UL94V-0V-0
Glass Transition Temp Tg
Celcius
Td (Decomposition Temp) by TGA – Celcius500500425425
Dk 1 GHz
Dk 2-3 GHz
Dk 10-12 GHz10.2 ± 0.503 ± 0.043.27 ± 0.0329.2 ±0.230
Df 1 GHz
Df 2-3 GHz
Df 10-12 GHz0.00270.0010.0020.0022
Moisture Absorption (%)<0.1%0.04%0.06%0.09%
CTE X-Axis (PPM/ºC) Pre Tg13171521
CTE Y-Axis (PPM/ºC) Pre Tg161521
CTE Z-Axis (ppm/ºC) Pre Tg34252320
Material ConsideredRFRFRFRF
Peel Strength – 1oz (35μm) – N/mm112.22
T260
T288 – minutes
Flexural strength – N/mm21.721.79
Young’s modulus – N/mm2
Tensile strength – N/mm2x – 3992
y – 3565		x – 930
y – 823
Volume Resistivity – MΩ/cm1×1031×1073×1092×108
Dielectric strength – V441285
Surface Resistivity – MΩ/cm1×1031×107>9X1094×107
Dimensional stability – mm/Mx- -0.06
y – 0.07
Thermal Conductivity – W/mK0.810.50.70.76