An X-Band State Adjustable Low Noise Amplifier Using Current Reuse Technique

This article presents an on-chip state-adjustable 8 GHz similar to 12 GHz low-noise amplifier (LNA). It has two characteristics. First, an improved current reuse topology is proposed. By connecting a small capacitor in parallel with the drain of the first-stage transistor, the bandwidth is expanded and the in-band flatness is improved. Second, an innovative adaptive bias circuit is designed to cope with the influence of temperature and process on the performance of the amplifier, and a design method for on-chip adjustment of the chip state is proposed for the first time. As a result of these technologies, the chip area is 1.1 mm x 0.8 mm, the chip provides 24.4 dB nominal gain with merely 0.75 dB noise at 10 GHz, and yields 14.5 dBm output power at 1 dB compression point (OP1dB) when biased at 30 mA quiescent current, meanwhile, gain, OP1dB, and quiescent current can be adjusted on-chip. This design improves the comprehensive performance of X-band LNA and provides more flexibility for system engineers in application. The chip is fabricated using Win Semiconductors' 0.15 um InGaAs pHEMT E-mode process.