A 0.3–1.4 GHz inductorless CMOS variable gain LNA based on the inverter cell and self-forward-body-bias technique

In this paper, a low noise amplifier with variable gain is proposed in the frequency range of 0.3–1.4 GHz. The proposed circuit is composed of two inverter cell stages in which a variable feedback resistance is used to control the gain in the second stage. In both stages, self-forward-body-bias technique is utilized to reduce the power consumption and improve the circuit performance. High voltage gain, wide range of gain variation, low power consumption, and low noise figure are the most important features of the proposed variable gain low noise amplifier. The circuit is designed and simulated in standard 0.18-µm technology, and consumes 146 × 108 μm2 of chip area. Operated with a supply voltage of 1.2 V, power consumption of the proposed amplifier is 8 mW with a wide flat gain ranging from −24.9 to 21 dB in variable-gain mode of operation. The proposed circuit in the high-gain mode, operates as a low noise amplifier with high performance and low power consumption where the gain is greater than 20 dB, S11 is less than −24 dB, and noise figure is less than 2 dB in the entire operating frequency range. In this case, the IIP3 is equal to −9.5 dBm.