A Near-Field Probe for Subwavelength-Focused Imaging

Author

Markley, Loïc ; Eleftheriades, George V.

Author_Institution

Edward S. Rogers Sr. Dept. of Electr. & Comput. Eng., Univ. of Toronto, Toronto, ON, Canada

Volume

58

Issue

3

fYear

2010

fDate

3/1/2010 12:00:00 AM

Firstpage

551

Lastpage

558

Abstract

A near-field antenna array probe is presented that can perform subwavelength-focused imaging at a distance of 0.25?? . The array is composed of a centrally fed dipole with open-circuited secondary dipoles placed less than half a wavelength away on each side. Together, they produce a subwavelength focal spot that can be used to detect the presence of small wire loops with subwavelength resolution. This is done by raster scanning the array over the focal plane and monitoring the probe return loss for perturbations. An experiment was conducted that verified the 1-D subwavelength imaging of two loops placed in the focal plane. The minimum resolvable loop separation was 0.31?? for the array probe compared to 0.72?? for the single-dipole probe. The array probe had a 13% resolution bandwidth for two loops spaced at 0.4??.

Keywords

antenna feeds; dipole antenna arrays; image processing; 1D subwavelength imaging; fed dipole; focal plane; loop separation; near-field antenna array probe; open-circuited secondary dipoles; perturbations; probe return loss; raster scanning; single-dipole probe; subwavelength focal spot; subwavelength resolution; subwavelength-focused imaging; wire loops; Near-field focusing; near-field imaging; subwavelength focusing; subwavelength imaging;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2010.2040409

Filename

5415526