A Two-Line Time-Domain Gating Method for Characterization of Test Fixture With via Hole Discontinuity

Abstract

The time-domain gating method (TGM) is an accurate and useful method to characterize the test fixtures used in the measurement of high-speed connectors. However, its accuracy can be degraded by the gating error when the test fixture contains the impedance discontinuity near the fixture end facing the device under test. To overcome this limitation, this letter proposes a two-line TGM (2LTGM) for characterizing the test fixtures having the discontinuities such as via holes. The proposed method does not require any modification of the test fixtures with the help of the proposed test structures and T-parameter extraction procedure. The experimental results show that the proposed 2LTGM has an 8 dB lower mean square error than the conventional TGM for the test fixtures having via hole discontinuities at the end. We expect that the 2LTGM can improve the accuracy for characterizing the test fixtures with any discontinuities not limited to the via holes.