Ultra-Low Noise Amplifier for X-Band SiGe BiCMOS Phased Array Applications

This brief presents, a low noise amplifier (LNA) with sub-1dB noise figure (NF) at X-Band. Different than generally known noise-and-power match technique, the presented LNA is designed by considering impedance between the base-collector terminals of an HBT in common-emitter configuration. The presented amplifier stage can achieve sub-1 dB NF performance with ~10 dB gain. The LNA dissipates 19.8 mW of dc power and has 0.77 dB NF while occupying 0.4 mm². It succeeds 1.5 dBm of input-referred compression point. To the best of authors' knowledge, the presented work achieves the best NF performance in the literature of any LNA that utilizes SiGe technology.

I. Introduction

Recent enhancements in integrated circuit technology give rise to steering the direction of the multiple antenna elements electronically, which allows fast beam scanning in phased array systems. In a phased array system, Transmit/Receive (T/R) module is one of the significant blocks in the system, due to being dominant in complete high frequency performance of the array, such as noise figure (NF), and total gain [1]. A general T/R module include various sub-blocks that have different functionalities; among these LNA is an essential block of the receiver chain, determining sensitivity performance and effecting overall gain, NF, and linearity of a receiver. In addition, LNA also suppresses noise that contributes the remaining blocks of the chain [2].