Design of a high efficiency class-F power amplifier with large signal and small signal measurements

In this paper, a modified class-F power amplifier is designed and implemented with new method at 900 MHz frequency. The meandered line compact microstrip resonant cell (MLCMRC), with simple structure is proposed to use as a harmonic control circuit (HCC). The proposed MLCMRC correctly acts as open-circuit at third and fifth harmonics and acts as short-circuit at second and fourth harmonics. In this design, the proposed PA is integrated with simple MLCMRC, while the large conventional matching lines are omitted, which leads to harmonics suppression, size reduction, and PAE improvement at same time. The proposed class-F power amplifier is characterized by small-signal and large-signal measurements to evaluate its performance. The maximum obtained gain for the proposed PA is 18.5 dB. Also, this design can obtain 74% PAE under 15 dBm input power, which shows 5% and 10% improvement in the maximum gain and PAE, respectively compared to the conventional class-F PA. Moreover, the applied MLCMRC resulted in the 36% size reduction, compared to the same PA without MLCMRC. (C) 2019 Elsevier Ltd. All rights reserved.