An Ultrawideband Power Amplifier Based on Negative Feedback

This letter explores the feasibility of incorporating a negative feedback structure into ultrawideband power amplifiers (UWB PAs) to enhance both gain and efficiency flatness. A design methodology for UWB PAs is provided, considering the influence of a negative feedback structure on power amplifier (PA) design. The desired load impedance space is determined using power and efficiency contours. The multisection Chebyshev impedance transformation serves as the output matching technique in designing the UWB PA. The measured results indicate that the PA delivers an output power between 42 and 44.8 dBm and a drain efficiency (DE) ranging from 57.6% to 71.3%, with a bandwidth of 0.33–3.7 GHz.