Técnica de mejora de la linealidad para amplificadores en tecnología FET de doble puerta

Abstract

In this paper, a novel bias control technique is proposed for obtaining a linear response in class C amplifiers based on Dual Gate FET technology. An illustrative DGFET transistor has been characterized in terms of its intermodulation distortion (IMD) behaviour versus input power, paying particular attention to the evolution of the gate-to-source voltage where the sweetspot appears. Using this technique, an amplifier has been designed, being the sweet-spot controlled over an 8 dB input power range, allowing a maximum gain variation of 1 dB. Finally, experimental results of this sweet-spot enhancement are shown, either using the classical twotone excitation or a real QPSK modulated signal.