Wearable Electromagnetic Head Imaging System Using Flexible Wideband Antenna Array Based on Polymer Technology for Brain Stroke Diagnosis

IEEE Trans Biomed Circuits Syst. 2019 Feb;13(1):124-134. doi: 10.1109/TBCAS.2018.2878057. Epub 2018 Oct 25.

Abstract

Given the increased interest in a fast, portable, and on-spot medical diagnostic tool that enables early diagnosis for patients with brain stroke, a new approach of a wearable electromagnetic head imaging system based on the polymer material is proposed. A flexible low-profile, wideband, and unidirectional antenna array with electromagnetic band gap (EBG) and metamaterial (MTM) unit cells reflector is utilized. The designed antenna consists of a 4 × 4 radiating patch loaded with symmetrical extended open-ended U-slots and fed by combination of series and corporate transmission lines. A mushroom-like 10-EBG unit cell arrays are arranged around the feeding network to reduce surface waves, whereas 4 × 4 MTM unit cells are placed on the back-side of the antenna to enable unidirectional radiation. The antenna is designed and embedded on a multilayer low cost, low loss, transparent, and robust polymer poly-di-methyl-siloxane (PDMS) substrate and optimized to operate in contact with the human head. The simulated and measured results show that the antenna has a fractional bandwidth of 53.8% (1.16-1.94 GHz), more than 80% of radiation efficiency, and satisfactory field penetration in the head tissues with a safe specific absorption rate. An eight-element array is then configured on 300 × 360 × 4.1 mm3 PDMS material covering an average human head size and used as a worn part of the imaging system. A realistic-shaped 3-D specific anthropomorphic mannequin (SAM) head phantom is used to verify the performance of the designed array. The imaging results indicate the possibility of using the designed conformal array to detect a bleeding inside the brain using a confocal image algorithm.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brain / pathology*
  • Computer Simulation
  • Electromagnetic Radiation*
  • Head
  • Humans
  • Imaging, Three-Dimensional
  • Magnetic Resonance Imaging
  • Microwaves
  • Numerical Analysis, Computer-Assisted
  • Phantoms, Imaging*
  • Polymers
  • Reproducibility of Results
  • Stroke / diagnosis*
  • Wearable Electronic Devices*

Substances

  • Polymers