• MUHARREM KARAASLAN

Articles written in Bulletin of Materials Science

• Metamaterial-based high efficiency portable sensor application for determining branded and unbranded fuel oil

In this study, we have developed an efficient metamaterial (MTM)-based portable fuel oil sensor in order to distinguish branded and unbranded fuel-oil samples. Electromagnetic properties of the fuel-oil samples are experimentallyobtained and these data are defined in numerical analysis to design and test the performance of MTM sensor. Then, simulated MTM-based sensor structure is fabricated and measured to observe the efficiency and agreement to numerical results. Numerical and experimental studies are conducted in the microwave frequencies of 10–11 GHz. The experiment results are in accordance with the simulation ones. It can be seen from the results that the proposed MTM-based sensor can be implemented into the sensor industry for distinguishing the branded and unbranded fuel oil for several frequency regions.

• Exhibition of polarization conversions with asymmetric transmission theory, natural like chiral, artificial chiral nihility and retrieval studies for K- and C-band radar applications

In this study, asymmetric transmission, natural chirality phenomena and a retrieval study with chiral metamaterials (MTMs) are numerically and experimentally focussed, investigated and discussed by examining the polarization conversion effect. Suggested multi-functional designs have simple geometries ($\pi$-shaped), low losses and huge optical activities. In addition, these new designs are numerically and experimentally retrieved in the study. The proposed model has many advantages with respect to the asymmetric transmission and chiral MTM studies in the literature. These advantages arehaving simple geometries ($\pi$-shaped), large asymmetric transmissions, small chirality like natural materials and also hug chirality can also be provided by rotating one of the resonators. Besides, the proposed structure can be easily reconfigured for other frequency regimes to provide new chiral MTMs or can be adopted for different application areas from defence systems to stealth technology which will be examined in our future studies.

• Electromagnetic simulations of polarization-insensitive and wide-angle multiband metamaterial absorber by incorporating double asterisk resonator

A novel multiband metamaterial absorber (MTMA) is proposed which is capable of well presenting a polarization-insensitive and wide incident angle stability in the microwave frequency range. The proposed MTMA comprisingtwo vertically stacked asterisk-based copper resonators separated by dielectric layer of flame retardant type four and backed with a thin copper film. High-frequency structure simulator was used to simulate the absorber and to depict surface current distribution. The results showed that the absorber is operated at three narrow bands with high absorptivity of about 92, 100 and 100% at frequencies of 2.75, 4.3 and 9.5 GHz, respectively. The position of the resonant peaks can be effectively tuned by adjusting the geometry parameters of the structure, thereby achieving a multiband, polarization-independent andwide-angle absorber. The designed structure is important for the application of sensors, thermal images and in constructing broad multiband signals for electromagnetic compatibility/interference.

• # Bulletin of Materials Science

Volume 44, 2021
All articles
Continuous Article Publishing mode

• # Dr Shanti Swarup Bhatnagar for Science and Technology

Posted on October 12, 2020

Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
Chemical Sciences 2020