MODELING AND MEASUREMENT OF WIDE FET STRUCTURES

A wide FET structure is considered as a voltage controlled directional coupler. A model for the device has been developed taking into accoun t its distributed nature. The variation with bias of the source-drain S-parameters is presented and the model compares very well with measur ed results up to 20 GHz. The results show large variations in forward coupling from source to drain. The model has been used to investigate the effects of different gate terminations. Improved performance was t hen predicted and obtained, with 50 OMEGA loads. For this case the gat e associated S-parameters are also presented.