Browsing by Author "Akarsu, Gokberk"

Now showing 1 - 6 of 6

Citation - Scopus: 2
Design of Triple-Band Bandpass Filter Using Inverted Microstrip Ridge Gap Waveguide for Ka-Band Applications
(IEEE, 2022) Cengiz, Mehmet Faruk; Nakmouche, Mohammed Farouk; Fawzy, Diaa E.; Allam, A. M. M. A.; Akarsu, Gokberk; Taher, Hany
In this paper, a triple-band inverted microstrip Ridge Gap Waveguide (RGW) filter is designed using a double octagonal ring resonator (RR) with corner cuts. The design parameters are optimized using the Finite Difference Time Domain (FDTD) method (CST studio simulator). The filter is implemented on Rogers RT5880 (epsilon(r) =2.2, thickness of 0.787 mm and loss tangent tan delta = 0.0009). It is selected because of its low losses at high frequencies. The proposed design operates within the Ka frequency band (27-40 GHz), with resonance frequencies of 32.32 GHz, 35.75 GHz, and 38.12 GHz. The return losses reach levels of about -35 dB, -25 dB, and -32 dB for the three bands, respectively. The filter exhibits a low insertion losses of about 0.6 dB, 1.1 dB, and 0.9 dB at the three resonant frequencies, respectively.
Citation - WoS: 1
Citation - Scopus: 4
Development of a Novel Ultra-Wideband Textile-Based Metamaterial Absorber for Mm-Wave Band Applications
(IEEE, 2022) Akarsu, Gokberk; Cengiz, Mehmet Faruk; Fawzy, Diaa E.; Zengin, E. Buse; Allam, A. M. M. A.; Taher, Hany; Cleary, Frances
This work proposes an ultra-wideband Metamaterial (MM) absorber for smart electronic textile (etextile) applications. The design is based on a novel cell geometry composed of two combined letter patches (A&S) printed on a grounded textile substrate. This unit cell geometry is specifically developed and optimized for millimeter-wave (mm-wave) applications. In this study, different types of textiles are considered, namely, Felt, Denim, and Polyester, and the achieved -10 dB reflective fractional bandwidths are about 50.36%, 44.49% and 41.42%, respectively. A comparison between conventional counterparts PCB-based dielectrics (FR-4 and Rogers RT-5880) and textile-based fabrics (Felt, Denim, and Polyester) indicates that the bandwidths exhibited by textile fabrics are significantly wider. This study also demonstrates that the bending of textile-based materials has an inverse effect on the -10 dB bandwidth, as the material's surface curvature increases. The current design is more compact, thin, and more efficient in terms of absorptivity in comparison to other reported absorbers and structures in the literature. The obtained results can be considered promising for the development of ultra-wideband e-textile-based applications such as energy harvesting, health monitoring, and camouflage systems.
Citation - Scopus: 3
Development of a Symmetric Metamaterial Absorber With Bandwidth Improvements for 5g Millimeter-Wave Applications
(Institute of Electrical and Electronics Engineers Inc., 2022) Akarsu, Gokberk; Buse Zengin E.; Nakmouche M.F.; Cengiz, Mehmet Faruk; Fawzy, Diaa E.; Allam A.M.M.A.; Taher H.
This study presents the development of a one-layer symmetrical Metamaterial Absorber (MMA) for millimeter-wave (mm-wave) applications. The target is to enhance the narrow band behavior and to achieve ultra-wideband with high absorptivity rates. The design is based on octagonal shaped cut rings and octagonal patches printed on grounded rigid substrate. A novel unit cell is developed and enhanced with the use of lumped elements technique to obtain ultra-wideband absorbers with high absorptivity rates. It is implemented on Rogers RT5880 with dielectric relative permittivity ? r=2.2, dielectric loss tangent of tan ?=0.0009, thermal conductivity of 0.2 W/m. K and with a 1.575 mm thickness. The characteristics of the MMA are examined in term of different resistive values, geometries, and angle of incidence. The obtained results show great enhancements in both the-10 dB bandwidth and in the absorptivity rates. The narrow bandwidth of the symmetrical design is enhanced by a factor of about 200 with average absorptivity of about 98% over the whole bandwidth. The current design is a very suitable for applications in the mm-wave. © 2022 IEEE.
Citation - WoS: 8
Citation - Scopus: 12
A Novel 5g Wideband Metamaterial Based Absorber for Microwave Energy Harvesting Applications
(IEEE, 2021) Akarsu, Gokberk; Nakmouche, Mohammed Farouk; Fawzy, Diaa E.; Allam, A. M. M. A.; Baskoy, Kadir; Cengiz, Mehmet Faruk
This paper proposes a novel design of a compact and thin metamaterials (MMs) based wideband absorber aiming at specific microwave energy harvesting for 5G applications. The developed unit cell is obtained by combining two letters-like patches printed on a grounded dielectric substrate. The developed operating band is achieved based on the superposition of the two-resonances generated by the two letters. The simulations are based on Rogers RT5880 (thickness of 1.575 mm, dielectric constant of epsilon r=2.2, loss tangent of tan delta=0.009) and FR-4 substrates (thickness of 1.2 mm dielectric constant of epsilon r=4.3, loss tangent of tan delta=0.02). The obtained results show a wide 10 dB absorption bandwidth in the frequency range between 18 GHz and 30 GHz with absorptivity close to 99% for normal and oblique incident up top to 30 degrees in the case of Rogers RT5880. An absorptivity rate of 96% is obtained for the cased of FR-4 because of high dielectric losses. The obtained results are reasonable compared to other studies in the literatures.
Citation - Scopus: 4
Optimizing Ridge Gap Waveguide Based Slot Antenna Shape for Maximum Gain and Bandwidth for Satellite Applications
(IEEE, 2022) Cengiz, Mehmet Faruk; Akarsu, Gokberk; Fawzy, Diaa E.; Allam, A. M. M. A.
This work proposes different V-band antennas optimized to operate at 70 GHz with various geometric slots. The development is based on substrate integrated gap waveguide (SIGW) technology. Five geometries are considered, namely, rectangular, circular, hexagon, T-shape, and U-shape, with the target of maximizing the realized gain and bandwidth. The Finite Difference Time Domain (FDTD) technique is used to optimize the design parameters (CST studio simulator). The overall size of the developed antenna is 8.4x7.2x0.87 mm(3). The maximum obtained realized gain is found to be 10.98 dBi for the antenna with a rectangular slot. The circular slot antenna shows the highest S-11 < -10 dB bandwidth of 5.35 GHz in the range 66.53-71.88 GHz. The developed slot antennas are very appropriate for point-to-point wireless communication systems and inter-satellite and mobile satellite applications.
Citation - Scopus: 1
An Ultra-Wideband Textile-Based Perfect Superstrate Metamaterial Absorber for 6g Applications
(Institute of Electrical and Electronics Engineers Inc., 2023) Allam, A.M.M.A.; Helala, M.A.; Ghanem, M.G.; Raafat, M.A.; Fawzy, Diaa E.; Akarsu, Gokberk; Abbas, M.A.
This paper presents an ultra-wideband textile-based perfect Metamaterial absorber for 6G applications. The design geometry of the unit cell is based on a modified split ring resonator and optimized akin to the word 6G. It enables a wideband in sub-THz at the standard of FCC. The structure consists of three layers; the ground layer, the textile layer, and MTM resonators. The two resonators are 6G and L shaped. The structure is optimized in terms of the different dimensions of both resonators. For more enhancement of the absorptivity band, superstrate textile material is added on top of the resonator's structure. It enhances the band by 6 %. The structure is subjected to different angles of incidence to study the sensitivity of the absorber to that angle. It contributes a bandwidth of 17.135 GHz up to 30 degrees and an FWHM of more than 33.332 GHz up to 45 degrees. The textile material used is felt having a permittivity of 1.27, thickness of 0.6 mm, and tangent loss of 0.016. The overall size of the absorber is 2.4 mm x 2.4 mm x 1.27 mm. © 2023 IEEE.