Highly-Efficient and Low-Power Class-E Amplifier for Miniaturization Using a Small Antenna

This paper presents the design of a low-power (200mW) highly-efficient VHF Class-E amplifier that can be directly integrated with a small (0.38λ) dipole CubeSat satellite antenna. This design is enabled by our novel procedure to shape the transistor drain voltage and current waveforms using only the conventional Class-E load circuit components. Our method attains a Class-E amplifier with a fundamental optimum load impedance equal to the low resistance (≤sssim 50Ω) and capacitance of a small antenna and simultaneously maximizes the drain efficiency for fixed output power and supply voltage. The prototype achieves a power-added efficiency (PAE) of 60.7% with an output power of 113.5mW for fixed supply voltage of 10V and power budget of less than 200mW, whilst directly interfaced with a 25-j147Ω small antenna load. This result demonstrates the potential of our proposed design approach to enable the miniaturization of small satellite communication systems.