Low noise distributed amplifiers （DAs） using the novel low noise composite-channel Al0.3 Ga0.7N/ml0.05 Ga0.95 N/ GaN HEMTs （CC-HEMTs） with 1μm-gate-length are designed and fabricated. Simulated and measured results of the DAs are characterized. The measured results show that the low noise DAs have input and output VSWR （voltage standing wave ratio） of less than 2.0,associated gain of more than 7.0dB and gain ripple of less than ldB in the frequency range from 2 to 10GHz. Noise figure of the DAs is less than 5dB in the frequency range from 2 to 6GHz,and less than 6.5dB in the frequency range from 2 to 10GHz. The measured results agree well with the simulated ones.
A current bleeding CMOS mixer with complementary transconductance stage is presented in this paper.The conversion gain of the mixer is increased and the flick noise of the mixer is reduced by inserting the PMOS to form current bleeding circuit in Gilbert mixer.The circuit is designed through SMIC 0.18um CMOS process,the LO frequency is 1.571GHz,RF frequency is 1.575GHz,simulation results show the conversion gain of the mixer is 18.5 dB,SSB NF is about 9.59dB,and third-order input intercept point(IIP3) is-4.6dBm.The mixer consumes 7.8 mA at 1.8 V power supply and the size of the whole layout is 0.73mm×0.68 mm.
ZHANG Sheng CHENG Zhiqun LI Jin ZHOU Pengfei XU Shenjun
