Find the value of a capacitor or an inductor with the miniVNA

How to find the value of a capacitor, an inductor or the resonance frequency of
a serial L/C circuit with the miniVNA using the vna/J software from DL2SBA.

Setup Connect the capacitor and the inductor to the miniVNApro 'DUT' SMA port
as shown on the photo. The vna/J software is running in 'reflection' mode.
For this test a 47 pF capacitor (C) and a 22 uH inductor (L) have been used.
In theory the resonance frequency of this L/C circuit should be 4.949 MHz.

Find the resonance frequency of the L/C circuit You can download the EXCEL sheet and use it as below.

Or run the vna/J software in 'reflection' mode.
You should get something like the graph below. The resonance frequency is where 'XS' equal to zero and
where 'RP' is equal to +180 or -180 degrees. In this case the resonance frequency is 5'137 MHz
because the inductor and the capacitor used for this test are not very precise, probably +- 10%

Find the value of an unknown capacitor (C) The value of the inductor is known (22 uH) and the value
of the resonance frequency taken from the vna/J chart is also known (5.137 MHz). Fill the Excel sheet
with those values, then you will get the capacitor value.

Find the value of an unknown inductor (L) The value of the capacitor is known (47 pF) and the value
of the resonance frequency taken from the vna/J chart is also known (5.137 MHz). Fill the Excel sheet
with those values, then you will get the inductor value.

This method is not very accurate, but it can give you an approximate value of the unknown element. Is much better if you can use a capacitor or inductor meter.