Impedance SWR
Calculate resistive-load reflection coefficient, SWR, and return loss.
Description
A resistive-load mismatch gives reflection magnitude, standing-wave ratio and return loss.
A resistive-load mismatch gives reflection magnitude, standing-wave ratio and return loss. Infinite boundary quantities use a largest-finite-number sentinel.1
Calculate resistive-load reflection coefficient, SWR, and return loss.
When to use Impedance SWR
Use this tool to calculate resistive-load reflection coefficient, SWR, and return loss.
Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
How to use Impedance SWR and understand its results
- Prepare the optical measurements, geometry, fitted coefficients or caller-selected thresholds requested. Confirm wavelength, radius/diameter, pulse-width, angle and unit conventions before running the calculation.
- Enter loadResistanceOhms, lineImpedanceOhms using the field table and calculation rules, then run the tool.
- Read reflectionCoefficientMagnitude, standingWaveRatio, returnLossDb. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| loadResistanceOhms | Resistive load (Ω) | number; minimum: 0 | Required |
| lineImpedanceOhms | Line impedance (Ω) | number; minimum: 0 | Required |
Enter nonnegative load and positive line resistance. At Γ≥1 return Number.MAX_VALUE for SWR and zero dB; at Γ=0 return SWR one and Number.MAX_VALUE for return loss.
Γ=|(R−Z)/(R+Z)|; SWR=(1+Γ)/(1−Γ); RL=−20log10Γ Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| reflectionCoefficientMagnitude | Reflection coefficient magnitude | number; minimum: 0; maximum: 1 |
| standingWaveRatio | Standing-wave ratio | number; minimum: 1 |
| returnLossDb | Return loss (dB) | number; minimum: 0 |
{
"input": {
"loadResistanceOhms": 75,
"lineImpedanceOhms": 50
},
"output": {
"reflectionCoefficientMagnitude": 0.2,
"standingWaveRatio": 1.4999999999999998,
"returnLossDb": 13.979400086720375
}
}Limitations and assumptions
Sentinels represent divergent limits, not physical finite readings. Reactive impedance, frequency and complex phase are excluded.
Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use PBS Extinction: Calculate PBS extinction ratio, decibels, and leakage fraction. For a complementary task, use Ring Isolation Ratio: Calculate forward/reverse isolation in a unidirectional ring cavity.
References
-
Impedance SWR — tool.io
Similar or alternative tools
- PBS Extinction
Calculate PBS extinction ratio, decibels, and leakage fraction.
- Ring Isolation Ratio
Calculate forward/reverse isolation in a unidirectional ring cavity.