Comparing high-frequency control devices

To evaluate the three semiconductor materials, a HEMT device structure was selected as optimum for highfrequency switching and control functions. The resistances and capacitances forming the HEMT equivalent circuit can be subdivided into configurations representing the two switch states (on and off). For most control applications, at frequencies of most interest, the on-- state impedance is mostly resistive while the off-state impedance is mostly capacitive.