LAMINATES: DK, DF AND TRACE WIDTH
What are the Dk and Df of Panasonic R-1566(W)?
Panasonic R-1566(W) has a dielectric constant (Dk) of 4.6 and a loss factor (Df) of 0.012 at 1 GHz, as published by its maker. A 50 ohm surface microstrip over a 0.2 mm dielectric comes out about 0.340 mm wide on it, against 0.353 mm on standard FR-4.
- Shengyi S1000H publishes the same Dk at 1 GHz; the two differ in Df: 0.012 against 0.011 for S1000H.
- Dielectric loss on that microstrip is about 0.045 dB per inch at 1 GHz, and the signal travels at about 154 ps per inch.
- Buried as a stripline between planes 0.4 mm apart, 50 ohms needs a trace about 0.117 mm wide.
50 ohm surface microstrip, 1 oz copper
| Dielectric height | Trace width on R-1566(W) | On standard FR-4 |
|---|---|---|
| 0.1 mm | 0.160 mm | 0.166 mm |
| 0.2 mm | 0.340 mm | 0.353 mm |
| 0.5 mm | 0.889 mm | 0.920 mm |
| 1.6 mm | 2.92 mm | 3.02 mm |
As published
| Property | Value |
|---|---|
| Tg (°C) | 148 (DSC) |
| Td (°C) | 350 |
| Dk @ 1GHz | 4.6 |
| Df @ 1GHz | 0.012 |
| Z-CTE (ppm/°C) | 40 |
| IPC-4101 | IPC-4101/94 |
| Lead-Free | Yes |
| Halogen-Free | Yes |
Nearest grades in the catalogue by Dk at 1 GHz
| Laminate | Dk | Df | Tg |
|---|---|---|---|
| Shengyi S1000H | 4.6 | 0.011 | 155 (DSC) |
| Shengyi S1141 | 4.6 | 0.015 | 140 (DSC) |
| ITEQ IT158 | 4.6 | 0.016 | 155 |
How this was counted
Dk and Df are the maker's published values at 1 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).