Sub-1-dB and Wideband SiGe BiCMOS Low-Noise Amplifiers for $X$ -Band Applications

In this paper, a design methodology for SiGe HBT-based low-noise amplifiers (LNAs) is proposed that can be utilized for both sub-1-dB noise figure (NF) and wide bandwidth as an alternative to the conventional simultaneous input noise and power matching technique. This paper focuses on the removal of the series base inductor and the inclusion of an output matching network as a design parameter that can be used to achieve both sub-1dB NF and wide bandwidth. The effects of the mentioned design parameters on NF and bandwidth are described and analyzed, including the comparison of results with the conventional design technique. To demonstrate the validity of the analysis and impact of utilizing base-to-collector capacitance on LNA performance metrics, two different LNAs implemented in a 0.13-μm SiGe technology. The first LNA achieves a lower than 1-dB NF with 26-dB gain at 8.5 GHz, and the second LNA exhibits wideband operation, with a better than 10-dB return losses in the range of 8-35 GHz and lower than 3-dB NF from 6 to 20 GHz. The sub-1-dB LNA reaches -17.3 dBm of input-referred compression point (IP1dB), with a power consumption of 62 mW and an area of 0.795 mm
²
. The wideband LNA achieves 17.6 dB of peak gain with a 48.5-mW power consumption and 0.69-mm
²
chip area. To the best of our knowledge, this paper achieves the best NF performance in the literature utilizing a SiGe technology, while the wideband LNA exhibits the best operational bandwidth, together with a reasonable low-noise performance.