Both GAN ( Gallium Nitride) and GaAs ( Gallium Arsenide) technologies and materials are important in the semiconductor industry. Specifically GAN on SiC is very important for high frequency high power circuits and Gallium Arsenide has been used in this arena for a while. In a few related posts we examine RF Integrated circuits and use of GAN technology, However, it is interesting to look at the fundamental properties of GAN and GaAs side by side. This has been done in a simple table and is available for interested readers in the Signal Processing Group Inc., website. Just click on the free articles ,,, link to access the table. In forthcoming articles and papers GAN devices, technology and applications are reviewed.