Load Pull Bias Tee

Abstract

Load-Pull measurement of high power devices requires the insertion of broadband impedance transformer jig between the connectorised set-up and the device under test. For stability and baseband impedance reasons, the biasing scheme is also implemented on the DUT side of these transformer circuits, and requires surface mount device format inductors and capacitors. The combined presence of the transformer and biasing circuit leads to some de-embedding inaccuracies as the broadband characterization of the transformer is altered by the biasing circuit. This paper describes how to improve the situation by splitting biasing and impedance transformation through the insertion of a load pull specific bias tee, which design is presented as well as its performance.