Multichip MMIC package for X and Ka bands

A new multichip monolithic microwave integrated circuit (MMIC) package operable to X and K_a bands has been developed and tested. This package provides space for mounting up to five MMIC chips and has three radio frequency (RF) and five dc feed-throughs. The RF feed-throughs are of a mixed-mode, conductor-backed coplanar waveguide design that minimizes reflections and insertion loss over a wide bandwidth. The dc feed-throughs permit bias access for up to five chips and internal mounting of chip bypass capacitors. Prototypes of the package have been built and tested using miniature coplanar probes. Test results indicate that the RF feed-throughs meet design goals to about 30 GHz and can be used to about 35 GHz. The package has been analyzed using a “Composite Model” approach in which individual elements are separately analyzed and modeled and then combined in a circuit simulator to provide a complete package model. This approach has provided quite good agreement with measured data