Performance with matched and unmatched wilkinson combiners

Two kinds of RF power combiner are studied. Matched Wilkinson combiner shows very good linearity but low power efficiency. Unmatched Wilkinson combiner used at the output of class-B amplifiers can be optimized in order to obtain the same good linearity of a matched Wilkinson combiner but better efficiency. Careful attention has to pay to the amplifier impedance to stop instability that may create undesirable oscillation in the system. Analytical and ADS simulation are presented to support this work. Excellent agreement between simulations and analysis is obtained in all cases considered.