Non-linear distortion in gallium arsenide MESFET control and switchcircuits

摘要

GaAs MESFETs offer significant advantages over conventional PINndiodes in many RF and microwave control applications. However, thenMESFET shows significant non-linearities that can affect its circuitnperformance at power levels less than 30 dBm, in contrast with the PINndiode which may be used to control kilowatts of power. It is thereforennecessary to determine the MESFET non-linear behavior so that meaningfulncomparisons may be made against PIN diodes in similar controlnapplications. The author presents a small-signal non-linear model fornthe MESFET, which is then used in a discussion of those MESFETnparameters controlling distortion in switch and attenuator applications.nIn addition, those factors controlling distortion that also play a rolenin governing the power handling and switching figure of merit in controlnMESFETs are discussed. The non-linear MESFET model is compared with anpreviously published non-linear PIN diode model under identical circuitnconditions. The non-linear MESFET model is verified with experimentalndata of second and third order harmonic distortion intercept point