Maker Label Studio

VSWR / Return Loss Calculator

Convert a single RF impedance match value into VSWR, return loss, reflection coefficient, and mismatch loss.

Input

Results

Cited category: Engineering & Surveying
VSWR
-
Voltage standing wave ratio.
Return loss
-
Higher return loss indicates a smaller reflection.
Reflection coefficient |Γ|
-
Magnitude of the RF reflection coefficient.
Mismatch loss
-
Power loss from impedance mismatch.

Engineering & Surveying formulas used

Self-tests

Self-tests have not been run.

About the VSWR / Return Loss Calculator

RF engineers, antenna installers, radio amateurs, and test technicians use a VSWR return loss calculator to convert between standing wave ratio, reflection coefficient, return loss, and mismatch loss. Enter any known value to see the equivalent impedance-match metrics. It helps interpret analyzer readings and datasheet limits without repeatedly applying logarithmic formulas by hand.

How it works

  1. Enter VSWR, return loss, reflection coefficient, or mismatch loss.
  2. Convert the value into the other common RF match metrics.
  3. Review whether the result meets the antenna, cable, or connector requirement.
  4. Use calibrated measurement equipment for acceptance testing.

Frequently asked questions

How are VSWR and return loss related?

Both describe impedance mismatch. VSWR is derived from the magnitude of the reflection coefficient, while return loss expresses reflected power as a positive dB value when reported in the common RF convention.

Is lower VSWR always better?

Lower VSWR means a better match, but system performance also depends on antenna pattern, feedline loss, bandwidth, power handling, receiver sensitivity, and installation environment.

What is mismatch loss?

Mismatch loss is the power not delivered to the load because some energy is reflected by impedance mismatch. It is calculated from the reflection coefficient and reported in dB.

Can return loss be negative?

Some instruments or S-parameter displays show S11 as a negative dB value, while return loss is often reported as the positive magnitude. Check the sign convention before comparing specifications.

Does VSWR identify the cause of a bad antenna system?

No. It shows mismatch severity, not the cause. Water intrusion, wrong connector, damaged coax, nearby metal, poor ground plane, or antenna tuning can all produce poor readings.

References