E-band automotive radar is an important growth area in the millimeter wave testing industry. Teradyne currently offers UltraFLEXplus RF solutions up to 24GHz. In this paper, a DIB based modular expansion solution for automotive radar testing on the UltraFLEXplus is introduced. On the UltraFLEXplus tester, an UltraWave24G instrument is used in conjunction with either an up-converter module (UCM) or a down-converter module (DCM) to source or measure a 76 to 81 GHz continuous wave (CW) signal. An optional switch Front-End-Module, either a single-throw-six-pole (SP6T) FEM or single-throw-eight-pole (SP8T) FEM, can be combined with either the UCM or DCM to present six or eight waveguide ports to the DUT. When using a DIB extension instrument such as these frequency converters, calibration is a concern. This paper will further describe the calibration solution and its usage in the production setting. In this paper, the authors will introduce the DX81 DIB extension instrument, review some key specifications, and present the calibration method.