VNA Setup Parameters
| Parameter | Typical Setting | Effect |
|---|---|---|
| Frequency range | Operating band ± 50% | Wider range reveals out-of-band behavior |
| Number of points | 401–1601 | More points → finer frequency resolution |
| IF bandwidth | 1–10 kHz | Narrower IFBW → less noise, slower sweep |
| Source power | −10 to 0 dBm | Low enough not to compress DUT; high enough for good SNR |
| Reference impedance | 50 Ω | Standard for all RF/microwave work |
SOLT Calibration Step-by-Step
- Connect Short standard to Port 1: VNA measures S11 ≈ 0 dB at 180°
- Connect Open standard to Port 1: S11 ≈ 0 dB at 0°
- Connect Load (50Ω) to Port 1: S11 should read < −40 dB
- Repeat S, O, L on Port 2
- Thru connection (Port 1 → Port 2): S21 = 0 dB ± 0.05 dB
- VNA computes error correction coefficients → calibration complete
Best Practices for Accurate Measurements
- Allow VNA to warm up 30+ minutes before calibration (frequency stability)
- Calibrate at room temperature; recalibrate if temperature changes >5°C
- Use phase-stable cables; avoid flexing between calibration and measurement
- Clean SMA connectors with IPA wipe before each connection
- Terminate unused ports in precision 50Ω loads (not open!) during measurement
- Torque SMA to 0.9 N·m (8 in-lbs) — not over-torqued, not loose
After Measurement: Export and Analyze with RF View
- Save measurement: File → Save Data → Touchstone → .s2p
- Select format: DB (most common), MA, or RI
- Transfer to Android (USB, email, cloud)
- Open in RF View → instant plot with all parameter views
- Auto Match → design matching network from measurement
RF View VNA Companion: After any VNA measurement, export .s2p and load in RF View for full analysis — Smith chart, matching design, Monte Carlo — on Android. Free on Google Play.