Ku-band low noise multistage amplifier MIC design having performance comparable to MMIC

Abstract

A novel common source three stage microwave integrated circuit (MIC) low noise amplifier (LNA) is designed, analyzed, fabricated and tested at Ku-band. Each stage is operated at 2V-15mA rating to achieve optimum desired gain-noise performance taking care of trade-offs. 30dB gain with 1.4dB minimum noise figure is achieved at 13GHz. Input port is noise matched giving input return loss of -13dB. Power matched output port provides output return loss of -27dB. It has -57dB isolation to ensure the unconditional stability. However, the circuit is also tested with 1V-2.6mA lower operating bias point. It keeps the DC power consumption as low as 7.8mW. In this case, the measurements show a 26dB gain with 2.14dB noise figure, -9dB input return loss, -18dB output return loss and -60dB isolation. MIC results show circuit's potential to achieve a comparable response to that of monolithic microwave integrated circuits (MMIC). Circuit performance is optimized by proper selection of the stability resistors for multistage configuration. Device used here is a high electron mobility transistor (HEMT). The circuit is fabricated on 25mil alumina substrate (εr=9.9, tanδ=0.0007 at 10GHz) with gold plated Kovar carrier plate.