12 GHZ LOW-NOISE MMIC AMPLIFIER WITH GAAS PULSE-DOPED MESFETS

A monolithic four-stage low-noise amplifier (LNA) was successfully dem onstrated for direct broadcast satellite (DBS) down-converters using 0 .3 mum gate pulse-doped GaAs MESFET's. This paper presents the design and test results of the LNA. The key feature of the research is a deta iled demonstration of the difference between a noise figure of the fou r-stage LNA and an optimal noise figure of an employed FET with simula tion and experiments. This LNA shows VSWR's of below 1.5: 1 as well as a noise figure of 1.1 dB and a gain of 28 dB at 12 GHz. To the best o f our knowledge, it is the lowest noise figure reported so far in 12 G Hz-band MMIC amplifiers. In the power characteristics, a 1 dB compress ion point (P1dB of 10 dBm and a third order intercept point (IP3) of 1 9 dBm were shown.