Bias Tee (T) Calculator

This tool calculates the Capacitor and Inductor values for a Bias T design.

Enter the following:

• Impedance
• Impedance ratio
• Frequency of operation

Formula

The minimum value of Capacitance is

C = 1/(2*π*f*X_c)

The Inductance value is

L = X_L/(2*π*f)

where

• f = Frequency of operation
• X_c = R/n
• X_L = R*n
• R = Impedance
• n = Impedance Ratio

Background

This calculator helps determine the Inductor and Capacitor values for a Bias Tee (also known as Bias T). Note that these are minimum values associated with the circuit.

Bias Tees are used in Software-defined radios and receivers.

USB Bias Tee

The Bias T shown below can be used to provide a voltage of +5V through the USB port or any other voltage using the DC header pins to power a remote amplifier.

HackRF One Software-Defined Radio