´New´ solutions of Class-E power amplifier with finite dc feed inductor at any duty ratio

`New´ Class-E solutions are proposed by varying three different design parameters which are introduced in the voltage and current equations in order to extend the Class-E `design space´, of which the `new´ solutions can apply to optimal and suboptimal operation. The design procedure of suboptimal Class-E power amplifier (PA) is analysed in details and then a suboptimal Class-E PA based on GaN HEMT CGH40010F is designed to prove the correctness of the `new´ solutions. The measured maximum output power of 39.6 dB, power-added-efficiency of 74.7% and drain efficiency of 78.9% were obtained at 2.6 GHz with a 28 dBm input power. These measurement results show that a similar or better level of efficiency and output power that are reported for optimal Class-E PAs at lower frequencies using the same transistor, and the presented `new´ solutions extend the `design space´ of Class-E PA. This paper give engineers more degrees of freedom to design Class-E PA.