This post by Ain Rehman. Looking through the literature a HEMT model that seems to be understandable and useful for hand calculations seems to be the Chalmers model. It is intuitive and resembles the familiar MOSFET type models that designers have been used to. Signal Processing Group Inc.is in the process of developing some useful relationships from this model that can be used for simple first order calculations for design. These relationships will be tested thoroughly and all assumptions validated. At the conclusion of this exercise a set of equations will be presented that will allow hand calculations to be made, to within a reasonable degree of accuracy as a starting point of a HEMT ( or pHEMT ) circuit design. Please visit our website for other technical information and our service and product offerings.