Modified class-F distributed amplifier

The class-F power amplifier is known for its high efficiency. The class-F single-ended dual-fed distributed amplifier integrates both class-F amplification and efficient power combining in the one circuit, without using additional n-way power combiners. In this letter the earlier reported circuit topology and design method is modified to account for drain parasitic reactances. A 1.8-GHz amplifier employing two packaged field effect transistors was designed and tested. The measured drain dc efficiency and corresponding output power with an input generator available power of 14 dBm was 71% and 22dBm, respectively.