Amplifiers for RF and microwave multichannel wireless systems

An amplifier for RF and microwave multichannel wireless systems where the third order IM distortion has been reduced is presented. The injection of the difference frequency of the two input signals in the amplifier together with the n fundamental signals will produce additional IM products at the output. By proper selection of phase and amplitude of the injected difference frequency signal, 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. As a result third order IM products will be eliminated, in principle. The experimental results on a commercially available amplifier are presented