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From bulk toward micro-structured TiO2 ceramics for all-dielectric metamaterials at terahertz frequencies: what process?
Published online by Cambridge University Press: 29 September 2025
Abstract
In this study, we aimed to develop high permittivity 
$\text{TiO}_{2}$ ceramics ideal for the fabrication of all-dielectric metamaterials (ADM) operational in the terahertz frequency. 
$\text{TiO}_{2}$ ceramic pellets have been fabricated from a commercial powder. A comparative analysis was conducted between spark plasma sintering (SPS) and conventional sintering process. Characterizations were then carried out in the range of 0.2–1.4 THz using THz time-domain spectroscopy. We observed that the samples fabricated by the SPS and post-annealing treatment exhibit a high permittivity associated with minimal loss (
${\varepsilon^{ \prime}} \simeq$ 100 and 
$\tan\delta \lt $ 0.015). These characteristics make these samples optimal candidates for achieving a negative or near-zero effective index in all-dielectric metamaterials. In addition, four micro-structuring processes were investigated to produce ADM operating in the terahertz range from the ceramics:
(i) micro-molding,
(ii) direct 
$\text{TiO}_{2}$ etching by inductively coupled plasma,
(iii) saw cutting and
(iv) femtosecond laser etching.
Information
- Type
- Research Paper
- Information
- Copyright
- © The Author(s), 2025. Published by Cambridge University Press in association with The European Microwave Association.
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