Analysis of the dual-fed distributed power amplifier

The dual-fed distributed amplifier is a variation of the conventional single-fed distributed amplifier. Namely, the input signal is fed to both ends of the input line and the power appearing at the ends of the output line is combined. This approach has the advantages of utilising power in both the forward and backward travelling waves on the output line, and the drain output power can be equalised among the FETs. In this paper, the operational behaviour of the dual-fed distributed power amplifier is investigated and the optimum operating conditions are identified. It has been shown that uniform power distribution can be achieved when the spacing between each FET is of the order of the guide wavelength and is dependent on the phase difference of the two input signals