The PCB was produced with the 4-layer stackup from Aisler (as of 2022):
| Layer | Base Th. | Final Th. | Material | εr | Df |
|---|---|---|---|---|---|
| Mask | Elppemer AS 2467 SM-DG | 3.70 | |||
| Top | 18 µm | 40 µm | Copper | ||
| 69 µm | 68.13 µm | Prepreg 1080 / R-1551 (W) | 4.30 | 0.013 | |
| 69 µm | 68.13 µm | Prepreg 1080 / R-1551 (W) | 4.30 | 0.013 | |
| 2 | 35 µm | 35 µm | Copper | ||
| 1130 µm | 1130 µm | FR4 Core / R-1566 (W) | 4.60 | 0.010 | |
| 3 | 35 µm | 35 µm | Copper | ||
| 69 µm | 68.13 µm | Prepreg 1080 / R-1551 (W) | 4.30 | 0.013 | |
| 69 µm | 68.13 µm | Prepreg 1080 / R-1551 (W) | 4.30 | 0.013 | |
| Bot. | 18 µm | 40 µm | Copper | ||
| Mask | Elppemer AS 2467 SM-DG | 3.70 |
The dielectric parameters are in the range from 2..6 GHz; for more details, see here.
The RF structures were simulated and optimized in CST.
S-Parameters of a 20 mm trace:
| Frequency | Loss |
|---|---|
| 1 GHz | 0.049 dB/cm |
| 6 GHz | 0.16 dB/cm |
| 8 GHz | 0.20 dB/cm |
Geometry:
Swept Parameters:
- Tline width: ±0.3 mm
- Prepreg thickness: ±20 µm
- Prepreg Dk: ±0.1 → almost no impact
Swept Parameters:
- Via diameter: 0.25 mm, 0.50 mm
- Via annular ring: 0.25 mm, 0.50mm
- Gap between annular rings is fixed at 0.025 mm.
S-Parameters:
Geometry:
S-Parameters:
Impact of GND-Cutout:
Geometry:
Top Cu:
Inner (GND) Cu:
S-Parameters:
Geometry:
