Microwave Imaging Using a Disordered Cavity with a Dynamically Tunable Impedance Surface

Journal Article (Journal Article)

We perform microwave imaging using a dynamically reconfigurable aperture based on a tunable disordered cavity. The electrically large cavity is cubic with a spherical deformation and supports a multitude of distinct electromagnetic modes that vary as a function of excitation frequency. With a set of irises introduced into one wall of the cavity, the cavity modes couple to spatially distinct radiative modes that vary as a function of the driving frequency. To increase the diversity of the radiated fields, we replace one of the cavity walls with a variable impedance surface consisting of a set of varactor-populated mushroom structures grouped into pixels. The reflection phase of each pixel is independently changed with application of a voltage bias, effectively altering the surface impedance. We demonstrate high-fidelity imaging and examine the role of the impedance-tunable boundary condition, revealing superior performance in comparison with just frequency-diverse measurements. We also demonstrate single-frequency imaging, which can significantly reduce the demands on the required microwave source. The dynamic cavity imager may find relevance in security screening, through-wall imaging, biomedical diagnostics, and radar applications.

Full Text

Duke Authors

Cited Authors

  • Sleasman, T; Imani, MF; Gollub, JN; Smith, DR

Published Date

  • November 29, 2016

Published In

Volume / Issue

  • 6 / 5

Electronic International Standard Serial Number (EISSN)

  • 2331-7019

Digital Object Identifier (DOI)

  • 10.1103/PhysRevApplied.6.054019

Citation Source

  • Scopus