VSWR Calculator
Calculate Voltage Standing Wave Ratio, reflection coefficient, return loss, and power transmission efficiency
Calculate VSWR Parameters
VSWR
Voltage Standing Wave Ratio
Reflection Coefficient
Γ (Gamma) - magnitude
Return Loss
RL in decibels (dB)
Mismatch Loss
IL in decibels (dB)
VSWR must be ≥ 1 (ideal value is 1:1)
VSWR Analysis Results
Minimal reflection, excellent impedance matching
Example Calculations
Example 1: Excellent Matching
VSWR: 1.2:1
Reflection Coefficient: Γ = (1.2-1)/(1.2+1) = 0.091
Reflected Power: 100 × 0.091² = 0.8%
Through Power: 99.2% (excellent efficiency)
Example 2: Moderate Mismatch
VSWR: 2:1
Reflection Coefficient: Γ = (2-1)/(2+1) = 0.333
Reflected Power: 100 × 0.333² = 11.1%
Return Loss: -20 × log(0.333) = 9.54 dB
Example 3: Poor Matching
VSWR: 3:1
Reflection Coefficient: Γ = (3-1)/(3+1) = 0.5
Reflected Power: 100 × 0.5² = 25%
Through Power: 75% (significant power loss)
VSWR Quality Guide
Key Formulas
Applications
Understanding VSWR and Transmission Line Theory
What is VSWR?
VSWR (Voltage Standing Wave Ratio) is a measure of impedance matching efficiency in RF transmission systems. It represents the ratio of maximum to minimum voltage along a transmission line, indicating how well the load impedance matches the characteristic impedance of the transmission line.
Key Concepts
- •Perfect Match: VSWR = 1:1 (no reflections)
- •Standing Waves: Result from forward and reflected waves
- •Power Loss: Higher VSWR means more reflected power
Practical Implications
Good VSWR (1:1 to 2:1)
- • Efficient power transfer
- • Minimal heating in transmission line
- • Good antenna performance
- • Suitable for most applications
Poor VSWR (>3:1)
- • Significant power loss
- • Heating of transmission line
- • Potential equipment damage
- • Reduced system efficiency
Related Parameters
Reflection Coefficient (Γ)
Represents the ratio of reflected to incident voltage. Range: 0 (perfect match) to 1 (total reflection).
Return Loss (RL)
Measures how much power is reflected back, expressed in dB. Higher values indicate better matching.
Mismatch Loss (IL)
Power loss due to impedance mismatch, expressed in dB. Represents unavailable power at the load.
Power Efficiency
Percentage of input power successfully delivered to the load versus reflected back to the source.