When You Need Batch SNP Processing
RF engineers accumulate hundreds of Touchstone files from VNA measurements, EM simulations, and component datasheets. Common batch operations include:
- Format conversion: Tools export in different formats (some in MA, others in DB or RI). Mixing formats causes overlay comparison errors.
- Port remapping: VNA fixture port order doesn't match schematic port convention
- Frequency resampling: Two files have different frequency grids — cannot directly compare or cascade
- S4P slicing: Differential-to-common-mode S4P needs to be sliced to port-pair S2P for single-ended analysis
- CSV export: Non-RF tools (Excel, Python) can't read Touchstone — need to convert to CSV
Step 1: Format Conversion (DB ↔ MA ↔ RI)
DB format: magnitude in dB + angle in degrees
Line: freq S11_dB S11_ang S21_dB S21_ang S12_dB S12_ang S22_dB S22_ang
RI format: real + imaginary parts
Line: freq S11_re S11_im S21_re S21_im ...
MA format: linear magnitude + angle
Line: freq S11_mag S11_ang ...
Conversion DB→RI:
mag_linear = 10^(S_dB/20)
re = mag_linear · cos(ang°·π/180)
im = mag_linear · sin(ang°·π/180)
In RF View Batch Converter: select all source files, choose target format, tap Convert. All files are rewritten with the new options line and data format in the same batch.
Step 2: Port Remapping
VNA physical port order: Port1=A, Port2=B (fixture A–B)
Desired schematic order: Port1=Input, Port2=Output
If VNA measured: P1=Output, P2=Input
Need to swap S21↔S12 and S11↔S22:
New S11 = old S22
New S22 = old S11
New S21 = old S12
New S12 = old S21
For S4P (duplexer): may need complete 4×4 matrix permutation
RF View Port Change: select port mapping from dropdown menu
Step 3: Frequency Resampling
File A: 100 MHz to 3 GHz, 201 points (linear)
File B: 700 MHz to 6 GHz, 501 points (logarithmic)
To compare or cascade them, resample to a common grid:
Target: 700 MHz to 3 GHz, 500 points, linear spacing
Method: linear or cubic interpolation of S-parameter real/imaginary parts
(NOT dB values — interpolate RI, then convert if needed)
RF View Frequency Change: set start, stop, number of points → Apply to all files
Step 4: SxP to S2P Extraction
S4P file (4-port duplexer): ports 1=TX, 2=RX, 3=ANT, 4=GND Extract TX→ANT path: S31 from S4P → save as S2P with port1=TX, port2=ANT S3P file (3-port power divider): port1=IN, port2=OUT1, port3=OUT2 Extract IN→OUT1: S21 from S3P → save as S2P RF View: select source port pair, extract to new .s2p file for single-path analysis
Step 5: Batch Export to CSV
Wide CSV format (one row per frequency, all S-parameters as columns): Freq_GHz, S11_dB, S11_ang, S21_dB, S21_ang, S12_dB, S12_ang, S22_dB, S22_ang 1.000, -0.45, 168.2, -15.3, -47.6, -38.2, -51.2, -0.62, 163.4 ... Summary CSV (one row per file — bandwidth, IL, rejection): Filename, f0_GHz, IL_dB, BW3dB_MHz, Rejection_dB, S11_min_dB filter_A.s2p, 1.815, 1.8, 40.5, 52.3, -15.2 filter_B.s2p, 1.817, 2.1, 38.9, 48.7, -13.6
RF View Batch Converter: Select any number of SNP files, then apply format conversion, port remapping, frequency resampling, and SxP slicing — all in one operation. Export to CSV for further analysis in Excel or Python. Available on Android without a PC.