A graphic design method for matched low-noise amplifiers

Author

Albinsson, Bj?¶rn M.

Author_Institution

Div. of Network Theory, Chalmers Univ. of Technol., Gothenburg, Sweden

Volume

38

Issue

2

fYear

1990

fDate

2/1/1990 12:00:00 AM

Firstpage

118

Lastpage

122

Abstract

A graphic design method for matched low-noise amplifiers is presented in which all necessary design information is given in the load plane. It is possible to work exclusively in the load plane, as the input-matching requirement makes the source admittance dependent on the load admittance. As a consequence of the bilinear transformation involved, all parameters may be presented by circles. Analytic equations giving the centers and the radii of the circles in the load plane are presented. Two kinds of amplifier configurations are considered: a single-stage amplifier with an input-match requirement and a two-stage cascade amplifier. The latter is required to have an output match and noise-optimized second stage, in addition to an input match. For the single-stage case the noise figure, the power gain, the stability, and the input network are treated. In the cascade design, the total noise figure, the interstage network, and the available gain are treated as well. A design example for the case of lossless feedback is presented

Keywords

amplifiers; cascade networks; graphs; impedance matching; network synthesis; LNA; available gain; bilinear transformation; graphic design method; input network; input-matching requirement; interstage network; load admittance; load plane; lossless feedback; matched low-noise amplifiers; network synthesis; noise figure; noise-optimized second stage; output match; power gain; single-stage amplifier; source admittance; stability; two-stage cascade amplifier; Admittance; Design methodology; Equations; Feedback; Graphics; Impedance matching; Low-noise amplifiers; Noise figure; Scattering parameters; Terrorism;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

Conference_Location

2/1/1990 12:00:00 AM

ISSN

0018-9480

Type

jour

DOI

10.1109/22.46419

Filename

46419