A 8–40 GHz, 8 mW LNA with 27 dB peak gain and 5.2 dB NF for multiband applications

An extremely-wideband, 8-40 GHz, low power Low Noise Amplifier (LNA) is presented in this paper. The LNA utilizes a novel combination of design techniques, namely resistive feedback, emitter degeneration, and shunt-peaked split-inductor to provide wideband input and noise matching. Furthermore, the LNA is designed as 3-stage amplifier to provide better gain control through stagger-tuning method, to meet gain specification across the entire band. The proposed LNA was implemented in 0.18 μm SiGe BiCMOS process with 150 GHz f_T. The design achieves a peak gain of 27 dB with minimum Noise Figure (NF) of 5.2 dB. The gain of the LNA is greater than 15.2 dB and NF is less than 7.2 dB from 8-40 GHz. The LNA consumes only 6.7 mA from a 1.2 V supply and occupies an area of only 0.26 mm². Using the proposed architecture, this work demonstrates LNA with extremely wide bandwidth and 3.7X improvement in FoM over comparable state-of-the-art designs.

I. Introduction

Traditionally, wireless transceivers operating in frequency bands such as X, Ku, K and Ka (7.3-to-40 GHz) are customized to operate in a single band. Recent advances in circuit design techniques have created the possibility to integrate all of the above bands into a single system, to create a multiband system. Such a system, capable of operating in all the above bands, would significantly reduce the physical size, and cost of operation in a multiband application environment and provide a reconfigurable front-end. In such a receiver, due to its position at the front, LNA is the most crucial block. However, design of such wideband LNA has proved far more difficult. Mainly, due to the challenges involved in achieving simultaneous wideband input and noise matching, while maintaining reasonable gain across all four bands of operation.