Low-noise amplifiers in wireless communications: state of the art, two new wideband all-active LNAs in SiGe-BiCMOS

Abstract

The aim of this paper is three-fold. First, it introduces the low-noise amplifier, its relevance in modern wireless communications receivers and the performance expected of it. Then, it presents an exhaustive review of the existing topologies, presenting their advantages and shortcomings. And finally, it introduces a new class of LNAs, based on current conveyors, describing the founding principle and the performances of two new LNAs, one single-ended and the other differential. Both these new LNAs offer the following notable advantages over existent topologies: total absence of passive elements (and the smallest LNAs in their respective classes); wideband performance, with stable frequency responses from 0 to 3 GHz; easy gain control over wide ranges (0-20 dB). Comparisons with other topologies prove that the new class of LNA implementations greatly advances the state of the art. These amplifiers are ideally suited to today's multiband receivers.

Analysis of process variations' impact on a 2.4 GHz 90 nm CMOS LNA

“…Narrowband common source inductive degenerated LNA (CS-LNA) has been widely used for short-range wireless CMOS implementations [1][2][3]. Among its weak point is its sensitivity to process variations.…”

Characteristics of interface states in irradiated Pd/n-SiGe as derived from frequency- and temperature-dependent admittance

“…SiGe technologies, known for their high transconductance at low current, are particularly attractive for high frequency low noise amplifiers as well as power amplifiers since SiGe is believed to have several advantages over GaAs in terms mainly of reduced chip area, chip robustness and reliability at high current densities [1][2][3]. SiGe heterojunction bipolar transistors are considered, in this context, as non-expensive alternative to AlGaAs/GaAs-based power amplifiers, which are key components in the wireless communication applications [4]. On the photodetection application front, the addition of Ge to Si is known to enhance the absorption coefficient over a wide spectral range, which allows a reduction of the detector thickness, and, therefore, enables faster detectors than with pure Si [5].…”