A novel EER structure for reducing complexity using negative resistance amplifier

This letter presents a novel envelope elimination and restoration (EER) structure using the negative resistance class F power amplifier. Due to the extremely high gain characteristic of the negative resistance amplifier in very narrow bandwidth, it operates in saturation mode. This characteristic is applied to the proposed EER. Using this technique, a limiter, a drive amplifier, and a class F power amplifier in conventional EER can be substituted with the negative resistance class F power amplifier. This technique greatly reduces the complexity of conventional EER without degradation of efficiency and linearity. The measured results show efficiency of 60% and less than-26 dBc IMD levels for two-tone test in PCS band at 27-dBm output power.