High efficiency GaN current-mode class-D amplifier at 2.6 GHz using pure differential transmission line filters

In class-D operation the impedances of the output network at each harmonic frequency at the intrinsic terminals of the transistors are of main importance. This reported work demonstrates a new concept using pure differential transmission line filters for the matching of these impedances. Furthermore, de-embedding techniques are used to compensate the impedance transforming characteristics of the package parasitics. A current-mode class-D (CMCD) amplifier with a power-added efficiency (PAE) of 62% and a corresponding output power of 29.5 W at 2.6 GHz has been demonstrated. To the authors% knowledge, these are the highest reported values of the PAE as well as the output power at this frequency for a CMCD.