Microwave probe for circuit/device testing

A probe for the high frequency measurement of discrete semiconductor devices in a naked form is described. Because conventional coplanar based probes cannot measure such devices directly, an artificial package usually needs to be fabricated to enable the device to be probed via the artificial package pads. The new probe avoids this need and overcomes the severe problems normally encountered in de-embedding the packaging effects from the device data. The design of the probe and its RF performance are described with the use of GaAs terminations. The usefulness of the probe in assessing packaging effects in microwave bipolar devices is demonstrated by measuring the S-parameters of a bipolar device in a naked and packaged environment