Multiband RF low noise amplifier (LNA) base on multi section impedance transformer for multi frequency application

In this paper, multiband RF low noise amplifier (LNA) is designed and evaluated. This LNA has a center frequencies 0.95 GHz for GSM, 1.85 GHz for WCDMA, and 2.45 GHz for WLAN application. In order to work on multifrequency, this paper proposed the use of multisession impedance transformer (MIT) as input matching (IM) and output matching (OM).The simulation is performed by Advanced Design System (ADS).The simulation result show that LNA at center frequency of 0.95 GHz has input return loss, S11 =-31.351 dB, output return loss, S22 =-26.004 dB, gain, S21 = 19.084 dB, noise figure, NF = 1.756 dB, stability factor, K = 1.593 and VSWR = 1.056. At center frequency of 1.85 GHz forwide-band code division multiple access (WCDMA) has input return loss, S11 =-25.013 dB, output return loss, S22 =-25.626 dB, gain, S21 = 12.968 dB, noise figure, NF = 1.995 dB, stability factor, K = 2.037 and VSWR = 1.119. At center frequency of 2.45 GHz has input return loss, S11 =-26.691 dB, output return loss, S22 =-26.984 dB, gain, S21 = 8.461 dB, noise figure, NF = 2.991 dB, stability factor, K = 3.024 and VSWR = 1.097. These result indicate that the multiband LNA can operated on the application GSM, WCDMA, and WLAN. These result also show that multisection impedance transformer can be used as impedance matching.