A 0.5 to 4.0GHz Low-Cost Broadband GaAs HBT Low Noise Amplifier

Abstract

In this paper, a compact Darlington low noise amplifier ranging from 0.5 GHz up to 4.0 GHz is proposed in 2μm InGaP/GaAs HBT technology offering fT of 30GHz. This Darlington topology is composed of two common emitter amplifiers, which is used to achieve both advantageous high gain capacity and broad operation bandwidth for multi-system application. A good input and output matching are obtained using a feedback method to achieve low noise performance by adjusting feedback resistor and inductor. Measurement results from 0.5 GHz up to 4.0 GHz show that the proposed low noise amplifier achieved a gain of 17 to 24 dB, a noise figure less than 4.5 dB and input and output voltage standing wave ratio (VSWR) lower than 1.44 and 2, respectively. The output 1-dB compression power is about 17.5 dBm to 20.5dBm. The chip size is only 1.2*1.48 mm2.