Transformer-based class-E CMOS PA with shunt LC network

This paper proposes a transformer-based class-E CMOS power amplifier (PA) with shunt LC network. The conventional class-E PA circuits contains a series inductor and capacitor in the load network; the proposed class-E PA was realized only with a pair of inductor and capacitor connected in shunt at the output load network. The shunt network exhibits a higher quality factor Q with a finite value of shunt inductor. Therefore, the presence of the higher order of harmonics in the output can be further suppressed and thus reducing the series resistance imposed by the shunt inductor. As a result, the efficiency is enhanced for a given output power.