VSWR
VSWR = (1 + |Γ|) / (1 − |Γ|)
Quick answer
This calculator solves VSWR = (1 + |Γ|) / (1 − |Γ|) for VSWR. With Reflection Coefficient |Γ| 0.0011, the result is 1.002. It solves in 2 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
Voltage Standing Wave Ratio measures the impedance mismatch between a transmission line and its load. A perfect match gives VSWR = 1:1 (Γ = 0), meaning all power is absorbed by the load. Higher VSWR values indicate worse matching with more power reflected back to the source. VSWR of 2:1 means about 11% of power is reflected, while 3:1 reflects 25%. Excessive VSWR can damage transmitter amplifiers due to reflected power and creates standing waves that cause voltage peaks along the transmission line.
Variables
- VSWR — Voltage Standing Wave Ratio (dimensionless, ≥1)
- |Γ| — Magnitude of reflection coefficient (0 to 1)
Practical Notes
VSWR targets: antenna systems <1.5:1, general RF <2:1, broadband acceptable <3:1. A VSWR of 1.5:1 corresponds to return loss of 14 dB and 4% reflected power. Network analyzers measure VSWR directly. In practice, achieving VSWR < 1.2:1 over a wide bandwidth requires careful impedance matching using stubs, transformers, or matching networks.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| VSWR | VSWR | — | — |
| gamma | Reflection Coefficient |Γ| | — | — |
Step by step
- 1. What you know: Reflection Coefficient |Γ| 0.0011
- 2. The relation: VSWR = (1 + |Γ|) / (1 − |Γ|)
- 3. Substitute: gamma = 0.0011
- 4. Result: VSWR = 1.002
Worked examples
Minimum range
Given: Reflection Coefficient |Γ| 0.055
Result: VSWR = 1.116
Low range
Given: Reflection Coefficient |Γ| 0.55
Result: VSWR = 3.444
Typical
Given: Reflection Coefficient |Γ| 0.0011
Result: VSWR = 1.002
High range
Given: Reflection Coefficient |Γ| 0.00176
Result: VSWR = 1.004
Maximum range
Given: Reflection Coefficient |Γ| 0.0176
Result: VSWR = 1.036
Solving for each variable
Solve for VSWR
Reflection Coefficient |Γ| 0.055 → 1.116
Solve for Reflection Coefficient |Γ|
VSWR 0.025 → -0.9512
How VSWR changes with Reflection Coefficient |Γ|
| Reflection Coefficient |Γ| (input) | VSWR (result) |
|---|---|
| 2.42 × 10⁻⁴ | 1 |
| 6.05 × 10⁻⁴ | 1.001 |
| 0.00121 | 1.002 |
| 0.001815 | 1.004 |
| 0.00242 | 1.005 |
| 0.00363 | 1.007 |
| 0.00484 | 1.01 |
| 0.00968 | 1.02 |
| 0.01694 | 1.034 |
| 0.0242 | 1.05 |
Embed this calculator
Paste this into any page. It keeps working when this page updates, and credits the source.
<iframe src="https://vbatpower.com/embed/vswr/" width="100%" height="460" style="border:1px solid #1f2a37;border-radius:12px" loading="lazy" title="VSWR"></iframe>
<p><a href="https://vbatpower.com/formulas/vswr/">VSWR</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate VSWR?
Use VSWR = (1 + |Γ|) / (1 − |Γ|). With Reflection Coefficient |Γ| 0.0011, VSWR works out to 1.002.
What is the formula for VSWR?
The formula is VSWR = (1 + |Γ|) / (1 − |Γ|). Voltage Standing Wave Ratio measures the impedance mismatch between a transmission line and its load.
How do you find Reflection Coefficient |Γ| when you know the other values?
Rearrange for Reflection Coefficient |Γ|: with VSWR 0.025, Reflection Coefficient |Γ| is -0.9512.
Related Concepts
All Signal & RF formulas →Need more features?
Save calculations, import telemetry data, simulate battery discharge, and collaborate with your team.
Try the App