The comparison of the linearity performance for three PHEMTs have been investigated in Ka band. The studied transistors are a single recessed PHEMT, a double recessed PHEMT and a double recessed dual channel PHEMT. The main result is : at a given output power level, the double recess allows a large improvement of the intermodulation ratio (IMR), thanks to its higher drain-source bias voltage capability, compared to the single recess. The second result is : the double recessed PHEMTs comparison shows that the dual channel, thanks to a more wide and uniform ransconductance distribution than the single channel, is a better solution for linearity application at 26GHz
