Output power performance of dual-fed and single-fed distributed amplifiers

Abstract

It is well known that the dual-fed distributed amplifier utilizes all FET output power, whereas up to a half is wasted in the single-fed distributed amplifier. We show that both the single-fed and antiphase-input dual-fed distributed amplifiers are able to achieve power equalization among the FETs at microwave frequencies when the FETs are spaced 180°. Such power equalization allows identical (and optimum) load lines for all FETs. The dual-fed amplifier has the added advantage of being less affected by losses.