The noise correlation matrixes of cascade representation

impedance representation and conductance representation of a two-port network were derived from basic circuit and noise definitions.The noise correlation matrixes of two linked two-port networks were also gotten from basic definitions.Then the noise parameters and

S

parameters of a parallel feedback low noise amplifier were derived using these correlation matrixes.A 1~7 GHz two-stage MMIC LNA was designed on the basis of above formulas and fabricated using 0.5μm GaAs PHEMT processes.After measurement

it is found that from frequency 1.0 GHz to 7.0 GHz

the LNA achieves a power gain of 20 dB as well as a good flatness of only ±0.75 dB

a maximum noise figure of 2.5 dB

input and output VSWRs of better than

2.0 and the output

P

1dB

power of 15 dBm.The design is verified by the measurement results of the MMIC LNA.