An MMIC low-distortion variable-gain amplifier using active feedback

Author

Nishikawa, Kenjiro ; Tokumitsu, Tsuneo

Author_Institution

NTT Wireless Syst. Labs., Kanagawa, Japan

Volume

43

Issue

12

fYear

1995

fDate

12/1/1995 12:00:00 AM

Firstpage

2812

Lastpage

2816

Abstract

A new low-distortion variable-gain amplifier (VGA) is proposed and analyzed. The VGA´s gain is controlled through changing the transconductance of a common-drain FET (CDF) in the negative feedback path. The analysis and prototype results indicate that the third-order intermodulation-distortion ratio is greatly improved at high input-power levels due to a drastic reduction in the VGA´s input impedance and the CDF´s unilateral characteristic. The gain in a wide temperature range maintains stability due to the combination effect of the transconductances of the CDF and the amplifying FET. This CDF feedback VGA is very useful for developing a wide-dynamic range front-end MMIC. The noise and thermal performances were also measured

Keywords

MMIC amplifiers; feedback amplifiers; field effect MMIC; integrated circuit noise; intermodulation distortion; microwave amplifiers; thermal stability; MMIC low-distortion amplifier; active feedback; common-drain FET; input impedance; intermodulation-distortion ratio; noise performance; thermal performance; third-order IMD ratio; transconductance; unilateral characteristic; variable-gain amplifier; wide-dynamic range front-end MMIC; FETs; Impedance; MMICs; Negative feedback; Noise measurement; Performance evaluation; Prototypes; Stability; Temperature distribution; Transconductance;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/22.475639

Filename

475639