This calculator finds the resistor values (R1) required for a reflection attenuator network, which reduces signal strength while maintaining impedance matching. It’s useful in RF circuits where controlled attenuation and stable impedance are critical.
Formulas
R1(Ω) < Zo = Zo × [ (10^(dB/20) – 1) / (10^(dB/20) + 1) ]
R1(Ω) > Zo = Zo × [ (10^(dB/20) + 1) / (10^(dB/20) – 1) ]
Formula Explanation
- Zo is the characteristic impedance (in ohms).
- dB is the desired attenuation level in decibels.
- The two resistor values maintain symmetry in the network, ensuring consistent reflection attenuation.
Example
Input: Attenuation = 121 dB, Zo = 5 Ω
Result: R1 < Zo = 5 Ω, R1 > Zo = 5 Ω
Who uses it
Helpful for RF engineers and test technicians designing attenuators for calibration setups and precise signal control.