Flexible ultra-wideband cartoon-shaped antenna based on a composite with customizable dielectric properties

Abstract

This paper presents a flexible ultra-wideband (UWB) and deformation-insensitive antenna. The proposed antenna was based on a Mickey-shaped patch, a coplanar waveguide fed, and a flexible composite substrate, which was built by a polydimethylsiloxane (PDMS) matrix and short-diameter powders of polytetrafluoroethylene (PTFE), with customizable dielectric properties. Furthermore, PTFE, magnesium oxide, titanium oxide, and zirconia powders were used as four fillers with different weight ratios to modify and control the dielectric properties of the dielectric substrate (the relative permittivity: 2.75–3.07, the dielectric loss tangent: 0.02–0.05), and then we characterized PDMS-based composites through Young’s modulus, Raman spectra, and surface topography. Finally, we fabricated and measured the proposed antenna with the dimensions of 50 mm × 60 mm × 0.5 mm. The measured reflection coefficient curves showed an operating frequency band from 1.9 GHz to 43.5 GHz, and the measured fractional bandwidth reached 183.3%. It was proved that the antenna had stable performance when it was bent or stretched. Moreover, the antenna was simulated and measured in the proximity of the human body, which verified the antenna robustness and safety for use on a human. The proposed UWB and deformation-insensitive antenna is a promising candidate for wearable applications and wireless communication.