HBT low power consumption 2-4.5 GHz variable gain feedback amplifier

The authors report the results on a 2-4.5-GHz GaAs HBT (heterojunction bipolar transistor) low-noise and ultralow-power feedback amplifier. The amplifier has a minimum noise of 3.9 dB and 10.5-dB gain with less than 40 mW of power consumption. The amplifier is self-biased through a 5-V supply. At optimum noise bias, the minimum noise figure is 3.7 dB with 15-dB associated gain. The amplifier gain ranges from 10.5 to 24 dB by changing the voltage supply from 5 to 12 V. The corresponding noise variation is 1 dB. At a maximum gain of 24 dB the corresponding noise figure and IP3 are 4.65 dB and 21 dBm.<
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