Flexible Meander-Line Antenna Array for Wearable Electromagnetic Head Imaging

• Published in: IEEE transactions on antennas and propagation Vol. 69; no. 7; pp. 4206 - 4211
• Main Authors: Alqadami, Abdulrahman. S. M., Stancombe, Anthony E., Bialkowski, Konstanty S., Abbosh, Amin
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.07.2021; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; Antenna arrays; Antenna measurements; Antennas; Compact antenna; electromagnetic (EM) head imaging; flexible antenna; Frequencies; Ground plane; Head; Image reconstruction; Imaging; Impedance; Lightweight; Low cost; meander-line antenna; Medical imaging; Microwave antennas; microwave imaging; on-body matched antenna; Reflectance; Room temperature; Substrates; Target recognition; Vulcanization; Wearable technology
• ISSN: 0018-926X; 1558-2221
• DOI: 10.1109/TAP.2020.3037742

Portable lightweight electromagnetic (EM) head imaging systems for brain stroke detection are of great interest due to the need for fast and low-cost diagnosis tools. This communication presents a wideband and compact flexible meander-line antenna array for a wearable EM head imaging system. The antenna is designed and optimized on a 4 mm thick low-cost, flexible room-temperature-vulcanizing (RTV) silicone substrate in close vicinity to a multitissue head model. The antenna comprises two sections of meander-lines, a full ground plane, and a <inline-formula> <tex-math notation="LaTeX">50~\Omega </tex-math></inline-formula> coaxial connector. The measured reflection coefficient <inline-formula> <tex-math notation="LaTeX">\vert \text{S}_{11}\vert </tex-math></inline-formula> on a human head shows that the proposed antenna operates effectively across the frequency band of 0.45-3.6 GHz, attaining fractional bandwidth (FBW) of 155%. The antenna achieves unidirectional radiations with greater than 9 dB of front-to-rear ratio in the near-field region, and safe-level maximum specific-absorption rate (SAR) below 0.2 W/kg using an input power of 10 dBm. A 16 element antenna array was assembled and experimentally utilized in an EM head imaging system. The reconstructed images of abnormality-emulating targets using a confocal imaging algorithm demonstrate the feasibility of utilizing such flexible and lightweight antennas for wearable EM head imaging systems.