Cascaded distributed power amplifier with non-identical transistors and inter-stage tapered impedance

A concept technique of cascaded distributed power amplifier (DPA) with non-identical transistors and controlled inter-stage tapered impedance for wideband applications is presented. The topology solves the gain peaking effect (expansion) at cut-off frequency and guarantees sufficient stability margins. The advantages of the proposed technique are explored analytically before prototype fabrication. At measurement level, 10 W output power, 32 dB gain and PAE (power-aided-efficiency) in excess of 15% are recorded from 70-2000 MHz. A good agreement between simulations and measurements was obtained.