Wideband reflection type MMIC attenuator with constant phase

Author

Nam, S. ; Ashtiani, A.E. ; Oztek-Yerli, C.F. ; Robertson, I.D.

Author_Institution

Dept. of Electron. Eng., King´´s Coll., London, UK

Volume

34

Issue

1

fYear

1998

fDate

1/8/1998 12:00:00 AM

Firstpage

91

Lastpage

93

Abstract

A method for reducing the unwanted insertion phase variation in an MMIC reflection type attenuator with wide bandwidth (>20 GHz) is described. The analogue reflection type amplitude control circuit uses cold-FETs as variable resistance reflection terminations. At high frequencies, very high phase variation is unavoidable due to the parasitic voltage-dependent reactance. Instead of tuning-out the parasitic reactance of the cold-FET, a novel symmetrical control method is presented for a two-stage attenuator. The phase shift variations from each stage cancel each other by the use of `complementary´ control signals

Keywords

field effect MMIC; waveguide attenuators; amplitude control circuit; cold-FETs; complementary control signals; constant phase; parasitic voltage-dependent reactance; phase shift variations; phase variation; reflection type MMIC attenuator; symmetrical control method; two-stage attenuator; unwanted insertion phase variation; variable resistance reflection terminations;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el:19980071

Filename

654542