Design of two stage low noise amplifier at 2.4 - 2.5 GHz frequency using microstrip line matching network method

Abstract

This study aims to design a Low Noise Amplifier (LNA) with two-stage cascade configuration at frequency of 2.4 -2.5 GHz. The transistor that used in this study has characteristic of high gain and low noise. The design is using microstrip line matching network with single stub technique to minimize parasitic effects. Transistor is using cascade configuration to produce high gain and improve the stability. The simulation results show that the LNA has reached all of expected specification at frequency of 2.45 GHz where S21, NF, S11, S22 are 30.693 dB, 1.248 dB, -70.358 dB and -72.982 dB, respectively; Also other values VSWR input, VSWR output, stability (K), input impedance and output impedance at 50 are 1.001, 1.0004, 5.280, 50.010 + j0.029 and 49.991 + j0.02, respectively. The measurement results show that at frequency of 2.45 GHz, LNA obtained value of S21, S11, S22, VSWR input, VSWR output are 22.17 dB, -4.117 dB, -13.049 dB, 4.297 and 1.572, respectively. Whereas, the best measurement of S21 is 24,05 dB at frequency of 2.05 GHz), S11 is -5.700 dB at frequency of 2.0 GHz, S22 is -27.570 dB at frequency of 2.045 GHz, VSWR input is 3.07 at frequency of 2,0 GHz and VSWR output is 1,09 at frequency of 2.045 GHz.