Compare VNWA Test Fixtures for S21 Measurement | Line Filters, Inductors, Capacitors and Resistors

This image verifies the difference in S21 data of a Vector Network Analyzer (VNWA3E) DG8SAQ when changing the measurement test fixture.

Verification will be performed using the two types of test fixtures below.

This image verifies the difference in S21 data of a Vector Network Analyzer (VNWA3E) DG8SAQ when changing the measurement test fixture.Verification will be performed using the two types of test fixtures.This is the first one.

Verify the difference in test fixture data using a 500 Ω resistor.

This image verifies the difference in S21 data for a Vector Network Analyzer (VNWA3E) DG8SAQ when changing the measurement test fixture. Verify the difference in test fixture data using a 500 Ω resistor.

Verify differences in test fixture data using common mode filters.

The difference in test fixture data was verified using a 100pF chip ceramic capacitor.

The difference in test fixture data was verified using a 100pF radial lead ceramic capacitor.

The difference in test fixture data was verified using a 1μH choke coil.

The difference in test fixture data was verified using a 150μH choke coil.

Differences in the test fixtures caused differences in the data at frequencies above several tens of MHz.
In particular, the accuracy of the capacitors improved to the point where differences in ESR were noticeable.
Test fixtures are important, but no test fixture is perfect.
All test fixtures are compromises in some way.

Verifying the performance of the test fixture for VNWA Thru mode (S21)