Direct Characterization of Non-Insertable Microwave Test Fixtures for Packaged MMICs

Non-Insertable Microwave fixtures used for testing packaged MMICs are often designed to transition from a coaxial environment at the signal source to either a microstrip or coplanar waveguide (CPW) transmission line at the Device Under Test (DUT). This transmission line becomes the interface between the automatic test equipment (ATE) and a lead of a packaged MMIC during electrical performance testing. Since the calibration reference plane is at the coaxial connector and not at the device under test, the measurements need to be corrected to compensate for the intervening structure. Because the network analyzer cannot be directly connected to the microstrip or CPW transmission line, it is difficult to directly measure the characteristics of this intervening structure. The task is further complicated by the need for a single set of calibration coefficients for a network analyzer that is to be used in a mixed connection environment. This paper presents one solution to the problem of directly and accurately characterizing the electrical performance of non-insertable MMIC test fixtures without using de-embedding procedures.