Experimental characterization of LINC outphasing combiners' efficiency and linearity

In this paper, an experimental characterization of the efficiency and linearity of resistive and outphasing combiners for linear amplification using non linear components (LINC) amplifiers is presented. The combining efficiency is measured for three combiners, i.e., one Wilkinson combiner and two Chireix combiners, with different electric stub lengths. The measured results are compared to theoretical predictions for the three cases. The nonlinear effects of Chireix combiners are highlighted and phase adjustment of one of the system's branches is proposed to linearize it. We show that linearization is feasible in this manner only at the expense of reduced efficiency.

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