Parasitic effects of spiral inductors on the performance of GaAs-based MMIC low noise amplifier

This paper is discusses about parasitic effect of spiral inductors on 5.8 GHz low noise amplifier (LNA) performances based on 0.5 mum GaAs pHEMT technology. Using S-parameter simulation, performance of the LNA between lump and distributed circuit are compared at 5.8 GHz. Electrical performance of the LNA performances by placing ideal components with non-ideal components shows that noise figure is increased by 2.31 dB, gain is decreased by 11.38 dB and input and output return loss is increased by 0.31 dB and 4.31 dB respectively. By using non-ideal components in the lump circuit analysis, it is shown that the spiral inductor has a noticeable impact on the LNA performance. The parasitic effects including self resonance on spiral inductors is discussed. This analysis is essential to ensure the simulation results yield realistic measured results for the fabricated LNA. Therefore the designer will have a good estimation on the performance of the LNA performance during the design stage prior to the testing stage.