# Ultra-Broadband Wearable Antenna with Thermal Sensitivity Based on Surface-Modified TiO2-PTFE-PDMS Nanocomposites

## TL;DR

Researchers developed a flexible, temperature-sensitive antenna using a special composite material that could be useful in wearable medical devices.

## Contribution

The novel contribution is the creation of a TiO2-PTFE-PDMS nanocomposite with tunable dielectric properties and thermal sensitivity for wearable antennas.

## Key findings

- The composite material showed optimal dielectric properties at a 5% KH570 mass fraction in the 2–12 GHz range.
- An ultra-wideband antenna with a frequency range of 2.37–11.66 GHz was fabricated using the composite.
- The antenna exhibited temperature-sensitive linear frequency shift characteristics suitable for thermal detection.

## Abstract

In this study, a composite substrate with adjustable dielectric properties was prepared, and its promising application in wearable medical device antennas was demonstrated. 3-Methacryloxypropyltrimethoxysilane (KH570) was used to modify titanium dioxide (TiO2) nano-powder, and the modified powder was blended with a mixture of polydimethylsiloxane (PDMS) and polytetrafluoroethylene (PTFE) under the action of anhydrous ethanol. The resulting polymer material had the advantages of hydrophobicity, softness, low loss, and a high dielectric constant. Meanwhile, the effects of the KH570 mass fraction on the microstructure and dielectric properties of TiO2-PTFE-PDMS composites were investigated, and the results showed that when the mass fraction was 5%, the composites exhibited better dielectric properties in the range of 2–12 GHz. Finally, an ultra-wideband antenna with an operating frequency band in the range of 2.37–11.66 GHz was prepared based on this composite substrate. The antenna demonstrated significant potential for future applications in detecting environmental thermal changes due to its special temperature-sensitive linear frequency shift characteristics, and its effect on the human body under bending conditions was studied. In addition, specific absorption rate (SAR) measurements were performed to assess the effects of antenna radiation on the human body in practical applications.