Usage Guide

This page covers the main workflows and features of touchstone.parser.

Parsing Files

Parse a Touchstone file from disk:

from touchstone.parser import TouchstoneParser

data = TouchstoneParser.parse("amplifier.s2p")

The parser auto-detects the number of ports from the file extension (.s1p, .s2p, .s3p, etc.) and parses the option line, comments, and data.

Accessing S-Parameters

Access individual S-parameters across all frequencies:

# Get S21 (transmission) as a complex array
s21 = data.get_s(to_port=2, from_port=1)

# Get S11 (reflection) as a complex array
s11 = data.get_s(to_port=1, from_port=1)

Access data at a specific frequency index:

# Get the FrequencyPoint at index 0
point = data[0]
print(point.frequency_hz)

# Access a specific parameter from the matrix
s11_at_point = point[0, 0]
print(s11_at_point.magnitude_db)

RF Calculations

Compute common RF metrics directly from the parsed data:

# Insertion loss (|S21| in dB, positive values)
il = data.to_insertion_loss()

# Return loss (|S11| in dB, positive values)
rl = data.to_return_loss()

# Voltage Standing Wave Ratio from S11
vswr = data.to_vswr()

Filtering Data

Filter data to a specific frequency range:

# Keep only data in the 2–3 GHz range
passband = data.in_frequency_range(2.0e9, 3.0e9)
print(f"Filtered points: {passband.n_freq}")

Use a custom predicate for advanced filtering:

# Keep only frequencies where S11 magnitude < 0.5
import numpy as np

filtered = data.where(lambda pt: np.abs(pt[0, 0].value) < 0.5)

Exporting Data

Export parsed data to CSV:

# Write to a CSV file
data.to_csv("output.csv")

# Or get the CSV as a string
csv_string = data.to_csv_string()

Write back to Touchstone format (round-trip):

from touchstone.parser import write_snp

write_snp(data, "output.s2p")

Conversion Utilities

Use standalone conversion functions:

from touchstone.parser import (
    db_to_mag, mag_to_db,
    deg_to_rad, rad_to_deg,
    ma_to_complex, db_to_complex, ri_to_complex,
    normalize_frequency,
)

# Convert -3 dB to linear magnitude
mag = db_to_mag(-3)  # ≈ 0.7079

# Normalize 2.4 GHz to Hz
freq_hz = normalize_frequency(2.4, "GHz")  # 2.4e9

Working with NetworkParameter

The NetworkParameter class provides rich access to individual S-parameter values:

from touchstone.parser.models.network_parameter import NetworkParameter

# Create from magnitude and angle
param = NetworkParameter.from_magnitude_angle(0.9, -45.0)

print(param.magnitude)       # 0.9
print(param.magnitude_db)    # ≈ -0.92 dB
print(param.phase_degrees)   # -45.0
print(param.real)            # real component
print(param.imaginary)       # imaginary component

# Arithmetic operations
result = param * 2.0
conjugate = param.conjugate()

Supported Formats

Feature

Supported

Touchstone v1.0 / v1.1

✅

1-port (.s1p)

✅

2-port (.s2p)

✅

Multi-port (.s3p, .s4p, …)

✅

Real-Imaginary (RI)

✅

Magnitude-Angle (MA)

✅

Decibel-Angle (DB)

✅

Hz / kHz / MHz / GHz

✅

S / Y / Z / H / G parameters

✅

Comments and metadata

✅