X-band Monolithic Low Noise Amplifier

This paper mainly introduce the circuit design,layout design and simulation result of X band PHEMT transistor MMIC low noise amplifier. It deeply researches extraction method of nonlinear model and optimization technique of CAD resign. Matching circuit, bias circuit and topology structure are all designed. So that, it achieves low noise and high gain as small-scale as possible, and ensures minimize of gate dimension and as high-linearity as possible.This MMIC LNA's working frequency is 9～11GHz. We use three-stage circuits of topology structure. This paper uses ADS design software. Each stage selects appropriate topology or circuit architecture appropriate for that particular LNA. Aim at noise factor, gain and VSWR proceed optimization. Input and output ports all match to 50ohm. After each stage achieves design demand, cascade of three-stage circuits proceed optimization.At last, the X band MMIC LNA achieves a noise factor of less than 0.75dB, a gain of more than 33.9dB, and good VSWR of less than 1.3 over the 9～11 GHz band. Input and output ports all match to 50ohm. It accords with the performance index.