High power added efficiency at 35GHz on InP DH HEMTs

A delta doped AlInAs/GaInAs on InP high electron mobility transistors (HEMT s) has been realised with an AlAs/AlInAs superlattice barrier layer and a g ate length of 0.25 mu m. A very high breakdown voltage of 10 V when the dev ice is operated as a transistor has been demonstrated. Power measurements. performed at 35 GHz with an active load pull bench, have shown that a state of the art power added efficiency of 43.2% has been obtained with an assoc iated power gain of 6.2 dB and an output power density of 200 mW/mm. The de vice was biased near to class B operation.