Coupled stepped-impedance resonator (CSIR) based concurrent dual band filtering LNA for wireless applications

Design and development of a concurrent dual-band filtering Low Noise Amplifier has been presented in this paper. Filtering LNA helps in the miniaturization and reduction in noise figure of the transceiver by eliminating an extra band pass filter (BPF) at the output. A CSIR based BPF structure has been used as output matching network. The dual-band bandpass filtering LNA drains 20-mA of current from a 2.8-V supply voltage. Proposed LNA achieves measured voltage gains of 11.6 and 8.9 dB, reflection coefficients of -25 and -12 dB, and noise figures of 3.96 and 2.85 dB at 2.4 and 5.7 GHz, respectively. Measured characteristics of the designed LNA show reasonable gain at widely separated pass bands in 2.4- and 5.7-GHz WLAN bands with ~ 40 dB of stopband attenuation.