Gain-Enhanced Distributed Amplifier Using Negative Capacitance

This paper presents a new high-gain structure for the distributed amplifier. Negative capacitance cells are exploited to ameliorate the loading effects of parasitic capacitors of gain cells in order to improve the gain of the distributed amplifier while keeping the desired bandwidth. In addition, the negative capacitance circuit creates a negative resistance that can be used to increase the amplifier bandwidth. Implemented in 0.13-mu m IBM's CMRF8SF CMOS, the proposed six-stage distributed amplifier presents an average gain of 13.2 dB over a bandwidth of 29.4 GHz. The measured input return loss is less than -9 dB and the output return loss is less than -9.5 dB over the entire bandwidth. With a chip area of 1.5 mm x 0.8 mm, the amplifier consumes 136 mW from a 1.5-V dc power supply.