Novel high gain and broadband GaAs MMIC distributed amplifiers with traveling-wave gain stages

Abstract

Using the concept of traveling-wave gain stages, novel GaAs MMIC distributed amplifiers are designed to achieve high-gain over several octaves of bandwidth. The cascaded single-stage distributed amplifiers (CSSDAs) are used as traveling-wave gain stages to improve the gain performance of conventional distributed amplifier (CDA). By selecting the low pass filter (LPF) topology for the CDA and CSSDA and tuning the gain shape of CDA and CSSDA, a wide-band performance of the broadband amplifier, called CDA-CSSDA-2 is obtained. The CDA-CSSDA-2 achieves 22 /spl plusmn/ 1.5 dB small signal gain from 0.1 to 40 GHz with a chip size of 1.5 /spl times/ 2 mm/sup 2/. This distributed amplifier produces gain-bandwidth product (GBW) of 503 which is the highest among all GaAs based distributed amplifiers. The flat group delay of the proposed distributed amplifier also proves the feasibility of this methodology for digital optical communications and broadband pulse applications.