Abstract
This paper presents the design and post-layout analysis of a dual-mode low-noise amplifier (LNA) operating in both narrowband (2.4 GHz) and ultra-wideband (3.1 GHz-10.6 GHz) frequency ranges, aimed at wireless communication applications. The narrowband LNA employs a single-stage inductively degenerated common-source configuration with a current reuse technique, while the ultra-wideband LNA utilizes a two-stage architecture with a double-resonance load network and resistive shunt feedback to ensure wide bandwidth and flat gain. Performance is further enhanced through source degeneration and cascoded feedback, optimizing impedance matching and gaining flatness across the ultra-wideband range. Implemented using 180 nm CMOS technology in Cadence Virtuoso, post-layout simulations demonstrate a gain of 17.9 dB for narrowband and 17.5 dB for ultra-wideband mode. The noise figure is 3.8 dB and 5.9 dB for narrowband and ultra-wideband modes, respectively. Both modes achieve input and output matching below - 10 dB, reverse isolation below - 40 dB, and power consumption of 25.41 mW (narrowband) and 14.79 mW (ultra-wideband) from a 1.8 V supply. The P1 dB is achieved at - 21.8 dBm for narrowband and - 18.8 dBm for ultra-wideband mode, with corresponding third order input intercept point (IIP3) values of -18.3 dBm and - 14.9 dBm. The LNA demonstrates stability with a factor (Kf) greater than 1 across both modes, ensuring robustness. The total post-layout area is 0.71 mm(2). This dual-mode LNA delivers strong performance across a broad frequency range with low power consumption and excellent stability, making it a viable solution for advanced wireless communication systems.