Each PCB material family is optimized for a different combination of electrical, thermal and mechanical requirements. The tables below summarize how the five major families compare so you can land on the right starting point before we sit down on a stackup review.
At-a-glance comparison
| Characteristic | FR-4 | High-Speed | RF / Microwave | Polyimide | Metal Core |
|---|---|---|---|---|---|
| Primary use | General electronics | High-speed digital | RF & microwave | Flex / high-temp | High-power / thermal |
| Typical applications | Consumer, industrial | Servers, networking, data center | RF, microwave, antennas | Flex, rigid-flex, aerospace | LED, power electronics |
| Dielectric Constant (Dk) | ≈ 4.0 – 4.7 | ≈ 2.9 – 3.6 | ≈ 2.2 – 3.0 | ≈ 3.4 – 3.8 | N/A |
| Dissipation Factor (Df) | 0.015 – 0.025 | 0.002 – 0.008 | 0.0009 – 0.003 | 0.006 – 0.012 | N/A |
| Thermal conductivity (W/m·K) | 0.25 – 0.4 | 0.3 – 0.6 | 0.2 – 0.5 | 0.2 – 0.4 | 1.0 – 8.0 |
| Tg (°C) | 130 – 180 | 170 – 200 | 150 – 200 | 250 – 350 | N/A |
| Td (°C) | 300 – 340 | 320 – 380 | 320 – 400 | 500+ | N/A |
| CTE (ppm/°C, z-axis range) | 55 – 70 | 45 – 65 | 30 – 50 | 20 – 45 | 15 – 25 |
| Operating temp range (°C) | −40 to +125 | −40 to +150 | −40 to +200 | −55 to +200 | −40 to +200 |
| Signal speed capability | Low – moderate | High (10–56+ Gbps) | Very high (GHz+) | Moderate | Low |
| Heat dissipation | Limited | Moderate | Limited | Limited | Excellent |
| Mechanical strength | Good | Good | Moderate | Excellent | Excellent |
| Flexibility | Rigid | Rigid | Rigid | Flexible | Rigid |
| Impedance control | Limited | Excellent | Excellent | Moderate | Limited |
| Manufacturing complexity | Low | Medium | High | High | Medium |
| Relative cost | Low | Medium | High | High | Medium – High |
Representative materials by family
| Family | Manufacturer | Material | Dk | Df | Tg (°C) | Typical use |
|---|---|---|---|---|---|---|
| FR-4 | Isola | FR406 | 4.2 | 0.017 | 170 | General electronics |
| FR-4 | Panasonic | R-1755V | 4.4 | 0.020 | 170 | Industrial PCBs |
| High-Speed | Isola | I-Speed | 3.6 | 0.005 | 200 | High-speed digital |
| High-Speed | Panasonic | Megtron 6 | 3.2 | 0.002 | 185 | Servers, networking |
| High-Speed | Rogers | RO4350B | 3.48 | 0.0037 | 280 | High-speed + RF hybrid |
| RF | Rogers | RO4003C | 3.38 | 0.0027 | 280 | RF & microwave |
| RF | Rogers | RT/duroid 5880 | 2.20 | 0.0009 | 500+ | Microwave, antennas |
| Polyimide | DuPont | Kapton | 3.5 | 0.007 | 360 | Flex & aerospace |
| Polyimide | Panasonic | R-F775 | 3.4 | 0.008 | 250 | Rigid-flex |
| Metal Core | Bergquist | Thermal Clad IMS | — | — | — | LED & power (k = 2.0–8.0 W/m·K) |
| Metal Core | Denka | Aluminum IMS | — | — | — | Power electronics (k = 1.5–5.0 W/m·K) |
How to pick the right family
| If your design is… | Best starting point |
|---|---|
| Cost-sensitive, general digital / analog | FR-4 (standard or High-Tg) |
| Multi-Gbps SerDes, switches, AI / HPC backplanes | High-speed (Megtron 6/7/8, I-Tera, Tachyon, Astra) |
| RF, microwave, mmWave, antennas | RF (Rogers RO4000, RT/duroid, ceramic-filled PTFE) |
| Flex, rigid-flex, harsh thermal cycling | Polyimide |
| LED lighting, motor drives, dense power conversion | Metal Core (aluminum or copper) — pair with heavy copper as needed |
Hybrid stackups
You don’t have to commit to one family. We routinely build hybrid stackups — for example Megtron 6 cores around the high-speed differential pairs, FR-4 elsewhere — to hit the performance you need without the full cost of an all-low-loss build.
Need help on your build?
Talk to a Sunrise PCB engineer.