Know what the numbers mean before you design
Tutorials and tools for RF engineers, with a plain-language layer for students.
Tutorials
Expert detail first, then a plain-language version.
VNA IF Bandwidth and Averaging: Noise vs Sweep TimeEach 10 dB of noise reduction costs about 10 times the sweep time, whether you cut the IF bandwidth by 10 or average 10 sweeps. Averaging cannot remove drift, systematic errors or crosstalk, so check those first.SOLT Calibration Step by Step: Short, Open, Load and ThruA SOLT calibration measures an ideal short (reflection coefficient -1), an open (+1) and a load (0), then a thru between the ports. The result holds only for the frequency range, IF bandwidth, power level and cable setup used.L-Network Matching: Low-Pass or High-Pass Version?Matching 50 ohm to 200 ohm needs Q = sqrt(3) = 1.732. The low-pass version uses 13.78 nH and 1.378 pF, the high-pass version 1.838 pF and 18.38 nH, and the choice depends on the DC path and the filtering you want.Microstrip Width for 50 Ohm on a 1.6 mm FR-4 BoardOn FR-4 (er 4.4) a microstrip line reaches 50 ohm at a width-to-height ratio of about 1.9, which is about 3 mm on a 1.6 mm board. Wider strips lower the impedance and narrower strips raise it.When to Put an Attenuator Pad in an RF ChainA fixed pad of A dB passes 10^(A/10) of the power, so a 10 dB pad passes 0.1 and turns the other 0.9 into heat. It can improve return loss by up to twice its attenuation, but it costs signal level and, in front of a receiver, noise figure.All tutorialsTools
Formulas and limits shown.
Attenuator padsdBm converterL-network matchingMicrostrip impedanceS2P viewerVSWR and return lossAll calculatorsRF View app: plot, simulate and batch-check S-parameters. Free for Windows and Android.Get the app