• Electronics and Telecommunications Trends
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• v.36 no.3
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• pp.119-132
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• 2021

To accommodate various mobile communication frequency bands, the study of metamaterial antennas have begun since the mid-2000s to solve the Trilemma problem between antenna gain-occupied bandwidth-size. As an adaptive reconfiguration function is required in a multi-array antenna system since 4G, the metamaterial array antenna using low-power variable elements has been used to change the basic structure of the antenna. Recently, reconfigurable intelligent surface (RIS), which is made of metasurface with reconfigurability, has been studied to effectively cope with the randomly varying radio channels and be used for various purposes such as reflection/transmission/modulation. As a result of RIS-related patent information analysis in this study, it was confirmed that most of the patents are metamaterial antennas and metamaterial array antennas, but the metasurface antenna technology was in the early stages. Particularly, as the intelligent metasurface antenna is in a more initial stage, the investment to R&D of RIS is urgent to secure patent competitiveness in B5G and 6G.

• Journal of Advanced Navigation Technology
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• v.28 no.2
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• pp.225-231
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• 2024

In this article, a new approach is presented to improve the unchangeable function of a ready-made millimeter-wave antenna system. By designing a metamaterial surface appropriate for the given geometry and fixed electrical characteristics of the device, the properties of the radiated fields of the RF product are changed to have directivity and higher antenna gain. Unlike other designs using periodic metamaterials for a single patch, an aperiodic metasurface is developed to handle two patches. For a higher received signal strength and a longer RF path in the 24 GHz-radio link, an aperiodic metasurface enhances the radiated fields by 10 dB.

• ETRI Journal
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• v.41 no.2
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• pp.160-166
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• 2019

A novel analytical method based on the cavity mode theory to design a metasurface (MS) is proposed in this study. We carefully analyzed the phase and amplitude characteristics of the incident wave and transmitted wave, and successfully designed a circular polarization conversion MS by introducing a cutting structure with wider operation bandwidth and higher radiation direction gain compared with that of the original MS. For the measurements, a microstrip antenna operating at 2.4 GHz was used as the source antenna to verify the designed MS. The simulation and measurement results agree well with each other.

• Journal of electromagnetic engineering and science
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• v.17 no.4
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• pp.202-207
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• 2017

This paper presents the performance of a planar, low-profile, and wide-gain-bandwidth leaky-wave slit antenna in different thickness values of high-permittivity gallium arsenide substrates at terahertz frequencies. The proposed antenna designs consisted of a periodic array of $5{\times}5$ metallic square patches and a planar feeding structure. The patch array was printed on the top side of the substrate, and the feeding structure, which is an open-ended leaky-wave slot line, was etched on the bottom side of the substrate. The antenna performed as a Fabry-Perot cavity antenna at high thickness levels ($H=160{\mu}m$ and $H=80{\mu}m$), thus exhibiting high gain but a narrow gain bandwidth. At low thickness levels ($H=40{\mu}m$ and $H=20{\mu}m$), it performed as a metasurface antenna and showed wide-gain-bandwidth characteristics with a low gain value. Aside from the advantage of achieving useful characteristics for different antennas by just changing the substrate thickness, the proposed antenna design exhibited a low profile, easy integration into circuit boards, and excellent low-cost mass production suitability.

• Journal of Satellite, Information and Communications
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• v.11 no.1
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• pp.37-40
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• 2016

We designed an antenna structure with the circular polarization metamaterial superstrate which increases the directivity of the primary antenna as a lens. The metamaterial superstrate removes the necessity of the array antenna and complicated feed. Plus, it provides the Fabry-perot cavity with the circular polarization. With regard to the primary antenna, a CRLH antenna is adopted to have the size-reduction from the conventional half-wavelength patch antenna.