A fusion bandwidth extension technique for broadband low‐noise amplifier

Summary Wideband low‐noise amplifiers (LNAs) are widely used in 5G and 6G communication systems. This paper first analyzes two common bandwidth extension technologies: the stagger tuning technique and the magnetically coupled resonators (MCR) technique. Then, a four‐stage LNA based on double‐tuned transformer combined with stagger tuning idea and MCR idea was proposed. In order to improve the broadband characteristics of the LNA, the loose coupling double‐tuned transformer is carefully designed. Compared with the traditional stagger tuning LNA, it has better broadband characteristics, lower element error sensitivity, and lower design complexity. This designs a gain bandwidth product of 1.48 T with a −3‐dB bandwidth in 9.11 GHz and the noise factor is lower than 3 dB, which covers more than 45% −3‐dB fractional bandwidth. The LNA consumes 37‐mW power with a 1.1‐V supply and occupies 1.22 × 0.4 mm2. According to the needs of broadband and multiband applications of LNA, this work combines two bandwidth expansion methods to design broadband LNA. The proposed design method has high gain bandwidth product, low element error sensitivity, and design complexity.