Balun S-Parameter Analysis Procedure
- Load balun .s3p file in RF View
- SNP Converter → Port Extraction: extract P1→P2 as "bal_pos.s2p" and P1→P3 as "bal_neg.s2p"
- Load both .s2p files simultaneously in S-Parameter Plot
- S21 dB overlay: both should be −3 dB (or spec'd coupling) at operating frequency
- Delta between two traces = amplitude imbalance (target <±0.5 dB)
- Switch to Phase view: Phase(P1→P3) − Phase(P1→P2) should equal −180°
- Delta marker: reads exact phase balance error vs 180°
Interpreting Results
| Measurement | Pass Criterion | RF View Method |
|---|---|---|
| Amplitude balance | |S21|−|S31| < ±0.5 dB | S21 overlay delta marker |
| Phase balance | |Phase(S31)−Phase(S21)−180°| < 5° | Phase view delta marker |
| Input return loss | S11 > 15 dB RL | BW Marker on S11 |
| Insertion loss | < 0.5 dB (typ), < 1.5 dB (max) | Single marker on S21 |
RF View Balun Analysis: Extract port pairs, overlay S21/S31 for amplitude check, use Phase view with delta marker for 180° balance. Free on Android.