A novel design method of highly efficient saturated power amplifier based on self-generated harmonic currents

A novel design method without requiring the special harmonic termination circuit for a highly efficient power amplifier (PA) is proposed. The proposed PA is driven into saturated operation, from the linear to knee region, by adjusting the only fundamental load, and the saturated operation induces self-generated harmonic currents. The current and voltage waveforms can be shaped easily by the harmonic currents, and efficiency of the PA is maximized. From the proposed design concept, a PA is implemented using 45-W GaN HEMT device at 2.655 GHz. The designed PA has a maximum drain efficiency of 71.5% at a saturated output power of 46.8 dBm for CW signal. The PA can be linearized to -46 dBc using the WDFBPD technique for a mobile WiMAX 2FA signal.