Power HEMT CAD for wireless communications applications

This paper presents a model for the breakdown process in power HEMT devices used in mobile communications systems. The model is integrated into a fast quasi-two-dimensional physical simulator. The work is based on a study of the complex interactions between the different breakdown mechanisms, including avalanche, and the influence of design parameters. The model takes account of the tunnelling effects in the region of the gate metallization. A new thermal model is included which monitors the channel temperature and controls the tunnelling mechanism. The design and measurements of 38 GHz MMIC power amplifiers designed for use in a QPSK communications link are presented.