Flat. 8 Mm Ultra-wideband Low-noise Gain Amplifier Is Developed

The noise figure of a microwave or millimeter-wave system basically lies on the noise of the front amplifier, so the Low Noise Amplifier (LNA) plays critical role for the receiving system.Countries all invest a great deal of manpower and material resources to the development of LNA, the trend is toward continuing to improve the performance of technical indicators.The 8-mm 26～40GHz and 18～40GHz ultra-wideband gain-flatness LNAs are designed based on Microwave Monolithic Integrated Circuit(MMIC),using the hybrid integration method of two-stage amplification.Because the amplitude-frequency characteristic after cascading two MMIC cannot meet the demand of the gain flatness, millimeter-wave microstrip gain equalizer is designed to amend the gain flatness of the ultra-wideband LNA.This thesis analyses and discusses the basic theory of the gain equalizer and the basic unit to achieve a balanced response. Microstrip resonator with resistance and the input and output matching circuits are maked to constitute a millimeter-wave microstrip gain equalizer design template.Computer optimization method is used to design the millimeter-wave microstrip gain equalizer.The most greatly equalized quantity of the millimeter-wave microstrip gain equalizer achieves 5dB in the 26⁴0GHz scope and achieves 3dB in the 18⁴0GHz scope.Testing results show that 26⁴0GHz ultra-wideband LNA:gain(G)>25dB, gain flatness(ΔG )≤+/-2.5dB, VSWR≤2, P_1dB>10dBm,noise figure(NF)<5dB.18～40GHz ultra-wideband LNA:gain(G)>22dB, gain flatness(ΔG )≤+/-2.5dB, VSWR≤2, P_1dB>8dBm,noise figure(NF)≤5.3dB.