A g/I-Based Low-Power LNA for Ka-Band Applications

Area of Science:

• Electrical Engineering
• Radio Frequency (RF) and Microwave Engineering
• Semiconductor Device Design

Background:

• The demand for high-frequency communication systems, particularly for 5G New Radio (NR) in the n257 band, necessitates efficient Low-Noise Amplifiers (LNAs).
• Traditional LNA designs often face trade-offs between power consumption, noise performance, and gain at high frequencies like Ka-band.
• The gm/ID methodology offers a promising approach for optimizing transistor performance in moderate inversion, crucial for low-power RF circuit design.

Purpose of the Study:

• To design and simulate a low-power, low-noise amplifier (LNA) optimized for Ka-band (28 GHz) 5G NR applications.
• To apply the gm/ID methodology at high frequencies (Ka-band) for the first time, exploring its benefits in RF/MW scenarios.
• To achieve a high figure of merit (FoM) by balancing gain, noise figure, and power consumption.

Main Methods:

• Implementation of a cascode LNA architecture using 45 nm silicon-on-insulator (SOI) technology.
• Application of the gm/ID methodology to optimize transistor operation in the moderate inversion region for enhanced efficiency.
• Post-layout simulations were conducted to evaluate circuit performance, including gain, noise figure, and return loss.

Main Results:

• The designed LNA achieves a very low power consumption of 1.98 mW from a 0.9 V supply.
• The amplifier operates at a central frequency of 28 GHz, suitable for the 5G NR n257 band.
• Post-layout simulations show a gain of 11.4 dB, a noise figure (NF) of 3.8 dB, and an input return loss (IRL) better than 12 dB.
• The design demonstrates a remarkable figure of merit (FoM) compared to conventional approaches, with performance metrics comparable to other designs but with significantly lower power usage.

Conclusions:

• The gm/ID methodology is effectively applied to a Ka-band LNA design, demonstrating its viability at high frequencies.
• The proposed LNA offers a competitive solution for 5G Ka-band applications requiring high performance and ultra-low power consumption.
• This design contributes to the advancement of efficient RF front-end components for next-generation wireless communication systems.