A 2.4/5.2/5.8 GHz Triple-Band Common-Gate Cascode CMOS Low-Noise Amplifier

This paper presents a 2.4/5.2/5.8 GHz, triple-band, common-gate, cascode CMOS low-noise amplifier using only a band-selection switch that alters the equivalent LC tank and thus the resonant frequencies of the tank. The aspect ratio of the cascode MOS device is designed to optimize the gain-bandwidth product of the proposed low-noise amplifier so that wideband performance can be achieved. The proposed triple-band low-noise amplifier is suitable for use in the frequency-partitioning scheme that utilizes a wideband frontend with three medium-sized bands, to implement wideband RF frontend architecture for software-defined radio. Theoretical analyses of the input impedance, noise factor, and three resonant frequencies of the switched LC tank that show good agreement with the experimental results are also presented. The measured 3-dB bandwidths of the three bands of 2.4, 5.2, and 5.8 GHz are 720, 1080, and 910 MHz, respectively, which demonstrate the feasibility of the proposed design methodology. The proposed low-noise amplifier provides forward gains () of 10.6, 17.4, and 15.6 dB, with minimum noise figures of 4.96, 5.16, and 5.57 dB, for the three operation bands. A test chip with a die area of was fabricated using a 0.18- RF-CMOS process. The proposed triple-band low-noise amplifier consumes only 3.6 mW, excluding the buffer, from a supply voltage of 1.8 V.