Return Loss(dB) Formula

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Return loss is a measure of the amount of power reflected back from a transmission line or an antenna, typically expressed in decibels (dB). Check FAQs
Pret=20log10(PiPref)
Pret - Return Loss?Pi - Incident Power Fed into Antenna?Pref - Reflected Power by Antenna?

Return Loss(dB) Example

With values
With units
Only example

Here is how the Return Loss(dB) equation looks like with Values.

Here is how the Return Loss(dB) equation looks like with Units.

Here is how the Return Loss(dB) equation looks like.

5.368Edit=20log10(15.25Edit8.22Edit)
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Return Loss(dB) Solution

Follow our step by step solution on how to calculate Return Loss(dB)?

FIRST Step Consider the formula
Pret=20log10(PiPref)
Next Step Substitute values of Variables
Pret=20log10(15.25W8.22W)
Next Step Prepare to Evaluate
Pret=20log10(15.258.22)
Next Step Evaluate
Pret=5.36796052285508dB
LAST Step Rounding Answer
Pret=5.368dB

Return Loss(dB) Formula Elements

Variables
Functions
Return Loss
Return loss is a measure of the amount of power reflected back from a transmission line or an antenna, typically expressed in decibels (dB).
Symbol: Pret
Measurement: NoiseUnit: dB
Note: Value can be positive or negative.
Incident Power Fed into Antenna
The incident power fed into antenna refers to the power that is delivered from the transmission line to the antenna.
Symbol: Pi
Measurement: PowerUnit: W
Note: Value can be positive or negative.
Reflected Power by Antenna
Reflected power by antenna refers to the power that is not effectively transmitted from a source, such as a transmitter or generator, into a load or an antenna system.
Symbol: Pref
Measurement: PowerUnit: W
Note: Value should be greater than 0.
log10
The common logarithm, also known as the base-10 logarithm or the decimal logarithm, is a mathematical function that is the inverse of the exponential function.
Syntax: log10(Number)

Other formulas in Transmission Line and Antenna Theory category

​Go Velocity Factor
Vf=1K
​Go Phase Constant in Telephone Cable
Φ=ωRC2
​Go Velocity of Propagation in Telephonic Cable
VP=2ωRC
​Go Voltage Maxima
Vmax=Vi+Vr

How to Evaluate Return Loss(dB)?

Return Loss(dB) evaluator uses Return Loss = 20*log10(Incident Power Fed into Antenna/Reflected Power by Antenna) to evaluate the Return Loss, The Return loss(dB) formula is defined as logarithmic ratio measured in dB that compares the power reflected by the antenna Pr to the power that is fed into the antenna from the transmission line Pi. Return Loss is denoted by Pret symbol.

How to evaluate Return Loss(dB) using this online evaluator? To use this online evaluator for Return Loss(dB), enter Incident Power Fed into Antenna (Pi) & Reflected Power by Antenna (Pref) and hit the calculate button.

FAQs on Return Loss(dB)

What is the formula to find Return Loss(dB)?
The formula of Return Loss(dB) is expressed as Return Loss = 20*log10(Incident Power Fed into Antenna/Reflected Power by Antenna). Here is an example- 5.367961 = 20*log10(15.25/8.22).
How to calculate Return Loss(dB)?
With Incident Power Fed into Antenna (Pi) & Reflected Power by Antenna (Pref) we can find Return Loss(dB) using the formula - Return Loss = 20*log10(Incident Power Fed into Antenna/Reflected Power by Antenna). This formula also uses Common Logarithm Function function(s).
Can the Return Loss(dB) be negative?
Yes, the Return Loss(dB), measured in Noise can be negative.
Which unit is used to measure Return Loss(dB)?
Return Loss(dB) is usually measured using the Decibel[dB] for Noise. Neper[dB], MilliDecibel[dB] are the few other units in which Return Loss(dB) can be measured.
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