Bias Tee Component Calculator

Posted by GPIO Labs on

GPIO LABS · RF TOOLS

Bias Tee Component Calculator

Enter your operating frequency range and system impedance to size the inductor and capacitor for a bias tee — and check whether a single L/C pair can realistically cover that range before you commit to a board spin.

Set equal to the minimum for a single-frequency (narrowband) design
System impedance
Reactance margin
MIN INDUCTANCE (L)
MIN CAPACITANCE (C)
XC (low)Z0XL (high)
How is this calculated?

Both components are sized against your minimum frequency, since that's where each has the hardest job: the inductor's reactance is at its lowest there (hardest to block RF), and the capacitor's reactance is at its highest there (hardest to pass RF). If both work at f_min, they only get better as frequency rises — at least until a real inductor's self-resonant frequency intervenes, which is what the feasibility check above accounts for separately.

Target reactances are set from your margin and impedance choice, then solved for component value: