Hi,

I am trying to measure quality factor,ESR and the inductance vales of chip inductors using a PNA in the 100Mhz to 6Ghz range. We have made a simple test fixture that has a SMA(m) connector and the other end of the connector connected to a PCB with a centre conductor and ground plane(See pic attached).

We do a one port cal over the frequency band. Then we do auto port extension by connecting the fixture and leaving it open.

Then we place the inductor between the centre conductor and the ground plane and read the values on the smith chart for the ESR(the real part) and the inductance value by placing markers at the frequencies desired. The q factor is calculated as the real part/imaginary part.

Is this an accurate method for measuring the inductors?Can we see the SRF(self resonant frequency) by looking at the frequency point where on the smith chart, the inductive impedance turns capacitive?

Rgds

I am trying to measure quality factor,ESR and the inductance vales of chip inductors using a PNA in the 100Mhz to 6Ghz range. We have made a simple test fixture that has a SMA(m) connector and the other end of the connector connected to a PCB with a centre conductor and ground plane(See pic attached).

We do a one port cal over the frequency band. Then we do auto port extension by connecting the fixture and leaving it open.

Then we place the inductor between the centre conductor and the ground plane and read the values on the smith chart for the ESR(the real part) and the inductance value by placing markers at the frequencies desired. The q factor is calculated as the real part/imaginary part.

Is this an accurate method for measuring the inductors?Can we see the SRF(self resonant frequency) by looking at the frequency point where on the smith chart, the inductive impedance turns capacitive?

Rgds

If you will be using the inductor shunt-to-ground, then mount it shunt-to-ground on a transmission line trace and measure all 4 S-parameters. In general, the S21 will be much more sensitive to SRF.

If youw ill be using it as a series element (such as a low pass filter) then place it in series with a transmission line.

I recomment to evaluate the inductor's equivalent value near the region where the resistance and reactance are of similar magnitude, as that is the point that the component value deviates strongly from ideal and is likely no longer usuable as for it's intended purpose.