6.78-MHz Class E Power Amplifier with Low Output Power Variation against the Load Impedance Variation

A power amplifier structure is presented that has a low output variation against the load impedance at 6.78 MHz using two Class E amplifiers and λ/4 transmission line. with another high are connected in parallel phase difference of 90° Each generates same under nominal conditions to achieve maximum efficiency. The can be reduced during operation, which increases from one decreases time when changed value. Therefore, efficiency maintained better compared conventional balanced structure. experiments show proposed an 16.18 %–18.4 6% less than For high-power mode both amplifiers, 13.54–21.53 W 75.41 %–80.16 % were obtained. An 4.67–8.76 77.89 %–82.48 obtained low-power mode, only operates.