Near-field analysis of a thick lens and horn combination: theory and measurements

Author

Tuovinen, Jussi ; Hirvonen, Taavi M. ; Räisänen, Antti V.

Author_Institution

Five Coll. Astronom. Obs., Massachusetts Univ., Amherst, MA, USA

Volume

40

Issue

6

fYear

1992

fDate

6/1/1992 12:00:00 AM

Firstpage

613

Lastpage

619

Abstract

At millimeter-waves quasi-optical systems are commonly designed based on the Gaussian beam and thin lens approximation. The accuracy of the Gaussian beam and thin lens approximation was studied in the case of a corrugated horn and a thick Teflon lens (focal length to lens diameter ratio f/D=1.2) combination at 87 GHz. A special near-field measurement system was constructed. A large disagreement between the measured and theoretical values with the approximative method was obtained. The measurements showed that the thin lens approximation breaks down when the distance from the input beam waist to the lens is less than 1.5 D. Theoretical values obtained with a thick lens model based on ray tracing and use of exact Huygens´ aperture integration principle agree well with the measurements

Keywords

antenna radiation patterns; lens antennas; waveguide antennas; 87 GHz; Gaussian beam; Huygens´ aperture integration principle; MM wave; Teflon lens; corrugated horn; horn antenna; lens antenna; near-field measurement; quasi-optical systems; ray tracing; thick lens; thin lens approximation; Extraterrestrial measurements; Laboratories; Laser beams; Lenses; Millimeter wave measurements; Millimeter wave technology; Optical beams; Optical design; Optical propagation; Thickness measurement;

fLanguage

English

Journal_Title

Antennas and Propagation, IEEE Transactions on

Publisher

ieee

ISSN

0018-926X

Type

jour

DOI

10.1109/8.144594

Filename

144594