LDMOS RF power amplifiers with improved IMD performance

An LDMOS RF power amplifier for RF multichannel wireless systems with improved performance characteristics such as intermodulation distortion (IMD) is presented. The injeclion of the fundamental signal second harmonics in the amplifier together with the two fundamental signals will produce additional IM products at the output. By proper selection of phase and amplitude of the injected second harmonic signals, it is possible to make the third order IM products produced by the second harmonics and the original third order IM products out of phase and equal in amplitude.