1.40/2.42/4.21-GHz Triple-Band Concurrent LNA Using Inductor Coupling

This paper presents a triple-band concurrent LNA using inductor coupling. The proposed triple-band matching circuit which is implemented for both input and output consists of the dual-band notch filter with the mutual induction circuit. This type of triple-band matching circuit realizes a small occupied area. The measured
$\boldsymbol{s}_{11}, \boldsymbol{s}_{22}, \boldsymbol{s}_{21}$
, and
$\it NF$
were -3.88, -19.72, 14.44, and 2.50 dB at 1.40 GHz, -9.21, -27.97, 14.17, and 2.97 dB at 2.42 GHz, and -8.85, -4.63, 9.96, and 3.02 dB at 4.21 GHz, with 22.8 mW under 1.8 V supply voltage, designed by using the 180 nm CMOS process.