250 W HVHBT Doherty With 57% WCDMA Efficiency Linearized to ${-}$ 55 dBc for 2c11 6.5 dB PAR

A two-way symmetrical Doherty amplifier exhibiting 250 W saturated power has been developed using high-voltage HBT (HVHBT) GaAs technology biased at 28 V on the collector. Greater than 57% collector efficiency at 50 W (47 dBm) average output power has been demonstrated while achieving -55 dBc linearized ACPR at 5 MHz offset using a two-carrier-side-by-side WCDMA input signal with 6.5 dB PAR measured at 0.01% probability on the CCDF. In addition, a two-stage HVHBT lineup exhibiting 450 W (56.5 dBm) peak power has been demonstrated. The output stage consists of a pair of 250 W two-way symmetrical Doherty amplifiers power combined using a low-loss branchline combiner and driven by a single-ended 100 W class AB high-efficiency amplifier. The lineup demonstrated 44% PAE at 100 W (50 dBm) average output power with 25 dB lineup gain while achieving - 55 dBc linearized ACPR at 5 MHz offset using a two-carrier-side-by-side WCDMA input signal with 6.5 dB PAR measured at 0.01% probability on the CCDF. The lineup exhibits 400 W (56 dBm) PldB at 60% PAE CW, with 45% PAE at 6 dB backoff.