LAMINATES: DK, DF AND TRACE WIDTH
What are the Dk and Df of Nanya NPG-198K?
Nanya NPG-198K has a dielectric constant (Dk) of 3.28 and a loss factor (Df) of 0.0016 at 10 GHz, as published by its maker. A 50 ohm surface microstrip over a 0.2 mm dielectric comes out about 0.440 mm wide on it, against 0.353 mm on standard FR-4.
- AGC/Nelco Meteorwave 8000 publishes the same Dk at 10 GHz; the two differ in Tg (°C): 200 (DMA) against 185 (DMA) for Meteorwave 8000.
- Dielectric loss on that microstrip is about 0.051 dB per inch at 10 GHz, and the signal travels at about 135 ps per inch.
- Buried as a stripline between planes 0.4 mm apart, 50 ohms needs a trace about 0.174 mm wide.
50 ohm surface microstrip, 1 oz copper
| Dielectric height | Trace width on NPG-198K | On standard FR-4 |
|---|---|---|
| 0.1 mm | 0.209 mm | 0.166 mm |
| 0.2 mm | 0.440 mm | 0.353 mm |
| 0.5 mm | 1.14 mm | 0.920 mm |
| 1.6 mm | 3.73 mm | 3.02 mm |
As published
| Property | Value |
|---|---|
| Dk @ 10GHz | 3.28–3.34 |
| Df @ 10GHz | 0.0016–0.0035 |
| Tg (°C) | 200 (DMA) |
| Halogen-Free | No |
| Target Data Rate | 400G+ |
Nearest grades in the catalogue by Dk at 10 GHz
| Laminate | Dk | Df | Tg |
|---|---|---|---|
| AGC/Nelco Meteorwave 8000 | 3.28 | 0.0016 | 185 (DMA) |
| Nelco Meteorwave 8000 | 3.28 | 0.0016 | 165 (TMA) |
| Shengyi Synamic 8GN | 3.28 | 0.0019 | 205 (DMA) |
How this was counted
Dk and Df are the maker's published values at 10 GHz, from the MPBxChange material catalogue, which keeps each source's test frequency and method. Where a maker publishes a range, the midpoint is used. Widths are solved with the Hammerstad and Jensen microstrip equations and Wadell's stripline form, for 1 oz copper, and are a starting point: Dk moves with frequency, resin content and glass style, and a fabricator's field solver is the authority. Standard FR-4 here is the median of 22 FR-4 grades in the catalogue (Dk 4.4).