Antenna Matching & Reflection Solver
VSWR to Return Loss Calculator
Convert Voltage Standing Wave Ratio (VSWR), Return Loss (RL in dB), Reflection Coefficient (Γ), and Mismatch Loss with transmitted vs reflected power percentages.
Voltage Ratio
: 1
Positive Magnitude
dB
Reflection Coeff (|Γ|)
0.2000
Mismatch Loss
0.1773 dB
Transmitted Power
96.00 %
Reflected Power
4.00 %
Engineering Reference
VSWR & Return Loss Industry Benchmarks
| VSWR | Return Loss (dB) | Reflection Coeff (|Γ|) | Transmitted Power % | Reflected Power % | Application Standard |
|---|---|---|---|---|---|
| 1.00 : 1 | ∞ dB | 0.000 | 100.00 % | 0.00 % | Theoretical Perfect Match (Zero Reflection) |
| 1.10 : 1 | 26.44 dB | 0.048 | 99.77 % | 0.23 % | Precision Calibration Standards & VNA Ports |
| 1.20 : 1 | 20.83 dB | 0.091 | 99.17 % | 0.83 % | Commercial FM/TV Broadcast Transmitter Output |
| 1.50 : 1 | 13.98 dB | 0.200 | 96.00 % | 4.00 % | Universal 4G/5G Cellular & Wi-Fi Antenna Spec |
| 2.00 : 1 | 9.54 dB | 0.333 | 88.89 % | 11.11 % | Marginal (Triggers PA Protection Power Foldback) |
| 3.00 : 1 | 6.02 dB | 0.500 | 75.00 % | 25.00 % | Severely Mismatched / Damaged Antenna Feeder |
Knowledge Base
Frequently Asked Questions
Common questions about RF power conversions, negative dBm, and voltage calculations.
First calculate the reflection coefficient magnitude: |Γ| = (VSWR − 1) / (VSWR + 1). Then compute Return Loss: RL (dB) = −20 × log₁₀(|Γ|). For example, a VSWR of 1.5:1 yields |Γ| = 0.5 / 2.5 = 0.20, which equals 13.98 dB Return Loss.
For commercial cellular and Wi-Fi networks, a VSWR ≤ 1.5:1 (Return Loss ≥ 14.0 dB) is standard, representing 96.0% transmitted power. High-grade broadcast transmitters require VSWR ≤ 1.2:1 (RL ≥ 20.8 dB). A VSWR ≥ 2.0:1 (RL ≤ 9.5 dB) triggers power foldback on modern transmitters to protect the final output transistors.
Return Loss is the ratio of reflected power to incident power (higher dB is better, representing less reflection). Mismatch Loss is the reduction in delivered load power caused by that reflection (lower dB is better; 0 dB is ideal).
Connecting a 50 Ω transmission line directly to a 75 Ω load produces a VSWR of 75 / 50 = 1.50:1, |Γ| = 0.20, Return Loss = 13.98 dB, and a Mismatch Loss of 0.177 dB (4% reflected power).
In rigorous network analysis (S-parameters), $S_{11}$ is negative (e.g. −14 dB). However, by convention, Return Loss is defined as a positive quantity: RL = −|S₁₁| dB. A return loss of 20 dB means reflected power is 20 dB below incident power.