VNA fixture
Convert length, one-way delay, and electrical angle, or estimate a line length from measured phase.
Blank length, delay, angle, phase values, or extra turns mean zero. Frequency and dielectric values are required. Use cable velocity factor or effective permittivity. Bulk board permittivity is not generally the effective value of a microstrip. These calculations assume a uniform, nondispersive line.
Port extension is entered as physical one-way delay per port; reflection compensation accounts for the round trip. Trace electrical delay follows the measured trace delay. The sign and entry convention depend on the instrument control; consult its help.
Enter two measured phase values at increasing frequencies. For a uniform line, decreasing unwrapped phase gives positive delay.
Unwrapped Δφ = end − start + 360° × extra turns. Example: +170° → −170° across a wrap uses +1 turn for +20°. Two samples cannot resolve the number of turns; choose it from the measured trace. Negative delay is shown as a signed estimate, not a physical cable length.
Reflection travels out and back through a fixture. Its trace phase slope represents twice the physical one-way delay; transmission through that same line represents one traversal. Phase-slope estimates can include DUT dispersion and resonance.
Static calculations in your browser. No measurement data is uploaded.