13.56 MHz class E power amplifier with 94.6% efficiency and 31 watts output power for RF heating applications

Radio frequency power amplifiers (RF PA) are widely used for several applications e.g. wireless communication, wireless power transmission (WPT) and radio frequency heating. In general, the choice of power amplifier´s operating class is based on requirements regarding linearity and power efficiency. For applications in which linearity is not a critical issue whereas high efficiency is desired, switched-mode amplifier e.g. class E is suitable. Switched-mode operation of class E offers high efficiency with a simple topology, leading to optimal costs of production and system operation. This work presents design and implementation of a high power and high efficiency 13.56 MHz class E power amplifier with parallel load circuit. As a power device, LDMOS was chosen. The fabricated class E PA provides Power-Added Efficiency (PAE) of 94.6% with 21.92 power gain when maximum output power of 44.92 dBm (31 W) is delivered to the load. Industrial, Scientific and medical (ISM) bands Class E PA with parallel load circuit.