Optimal dual-band impedance transformers with wide bandwidths for frequency dependent complex loads

Presented is a synthesis method for dual-band impedance transformers (DBIT) for an RC type of complex load, with the advantage of optimal performance for given required bandwidths. A lowpass to dual-bandpass frequency transformation is applied to the classic lowpass prototype matching network, resulting in a DBIT network whose ending impedance levels are changed by impedance de-normalization and by inserting an ideal transformer. Measured results have validated the feasibility of the method.