Design Techniques and Intermodulation Analysis of Broad-Band Solid-State Power Amplifiers

This paper presents balanced circuit techniques for the reduction and cancellation of the dominating third-order intermodulation tion product generated by broad-band solid-state power amplifiers. These techniques are applicable to collocated transmitters where the interference enters through the output port of the transmitter. A rigorous derivation is presented to prove the validity of the intermodulation canceliation by using a quadrature-hybrid coupling scheme in a balanced circuit configuration. The results are valid for arbitrary nonlinear characteristics exhibited by general classes of amplifiers, as well as isolators.