Pad-open-short de-embedding method extended for 3-port devices and non-ideal standards

This paper presents an extension of a three step de-embedding (Pad-Open-Short) method to a 3-port device for accurate on wafer MMIC S-parameters measurements. In the proposed method, an equivalent circuit-model using lumped elements is established according to the test-fixture. Furthermore, classical Pad-Open-Short method introduces systematic errors, observed beyond 20 GHz, due to perfect ‘Open’ and ‘Short’ standards assumption. This work also proposes a generalized Pad-Open-Short method with non-ideal standards. To validate the performance of this new method, reliable data were obtained from simulations and measurements of a GaAs transistor from UMS foundry operating up to 40 GHz.