Experimental microwave-signal-propagation study on GaAs MESFET's using especially fabricated transistor structures

Wave-propagation along the electrodes of an FET is reported to be experimentally investigated. A GaAs MESFET with large "gate width" and connecting pads at both ends of the gate and drain electrodes was fabricated. Using S-parameter measurement wave impedances, attenuation- and phase constants were obtained. Based on these measured S-parameters, the loads required at the normally open ends of the gate and the drain lines were calculated in order to achieve a maximally available gain (MAG) for the normal two-port transistor. These calculations are in very good agreement with the experimental results obtained by producing the required free-end loading terminations by tunable loads. It is thus also shown that a significant improvement of the MAG is possible.