Correlation between gate current and RF power performances of millimeter HEMT's

An original study on the power limitations of PHEMT's is presented using the gate current as criterion. Firstly, the optimal biasing point is determined using the DC gate current. Secondly, power measurements are performed with an automated active load pull system (2640GHz) to establish correlation between gate current and output power limitation. The behaviour of the gate current versus load impedances is also investigated. It is then possible to optimize the power performances to provide physical understanding and allow a reverse engineering.