Araştırma Çıktıları | WoS | Scopus | TR-Dizin | PubMed
Permanent URI for this communityhttps://hdl.handle.net/20.500.14719/1741
Browse
17 results
Search Results
Publication Metadata only Low-Powered Agriculture IoT Systems with LoRa(Institute of Electrical and Electronics Engineers Inc., 2020) Kokten, Esma; Çalişkan, Bahadir Can; Karamzadeh, Saeid; Gelal, Ece; Aboltins, A.; Litvinenko, A.; Kokten, Esma, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Çalişkan, Bahadir Can, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Gelal, Ece, Department of Computer Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyMonitoring is key to increase the efficiency of food storage in the open field in terms of cost, logistics and quality of the crops. For the long range data transmission in such environments, mobile technologies are not suitable, as the end devices are generally battery-limited. In this work, a prototype has been developed for monitoring goods in storage. The battery life time of this prototype is analysed in terms of calculations as well as measurements, on LoRa technology. Our results show that (i) while sleeping current has the smallest percentage, it has the greatest impact in increasing battery life, (ii) monitoring node shall have low self discharge battery for long battery life, and (iii) sensors are the main power sink that deplete battery. © 2020 Elsevier B.V., All rights reserved.Publication Metadata only Wide Angle Frequency Scanning Antenna for X-Band Applications(Institute of Electrical and Electronics Engineers Inc., 2020) Karamzadeh, Saeid; Rafiei, Vahid; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Rafiei, Vahid, Microwave and Antenna Group, GraphenePi Company, Istanbul, TurkeyBeam Steering antennas are a significant part of the communication systems applications requiring tracking or frequent repositioning. In this work, a new high gain broadband leaky-wave antenna is presented for X-band applications. The impedance bandwidth of the proposed Antenna is 32.65% and the scanning angle is 160 degrees. The fabricated antenna results are in good agreement with the simulation results. © 2021 Elsevier B.V., All rights reserved.Publication Metadata only Circularly Polarized MTS Based Antenna Design for C Band Applications, C Band Uygulamalar icin Dairesel Polarize MTS Tabanl Anten Tasarm(Institute of Electrical and Electronics Engineers Inc., 2020) Karamzadeh, Saeid; Rafiei, Vahid; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Rafiei, Vahid, Microwave and Antenna Group, GraphenePi Company, Istanbul, TurkeyA new broadband metasurface (MTS) circularly polarized (CP) patch array utilizing a sequential-phase feeding network is presented. In this study, the MTS method is used to increase the 3-dB axial ratio (AR) and impedance bandwidths. The prototype of the proposed array has been fabricated to validate designed parameters. The measured S11<-10dB is 2.1 GHz (4.5-6.6 GHz), and the measured 3-dB AR bandwidth is 1.3 GHz (4.9-6.2 GHz). The measured peak gain is about 16.4dBic and the gain variation is less than 3 dB within the AR bandwidth. © 2021 Elsevier B.V., All rights reserved.Publication Metadata only A New Approach for Age Estimation System Based on Speech Signals(Institute of Electrical and Electronics Engineers Inc., 2021) Fidan, Armagan; Bircan, Rabia Ozge; Karamzadeh, Saeid; Fidan, Armagan, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Bircan, Rabia Ozge, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyDeveloping technology and innovations have led to the development in many areas, and the age estimation with the human voice is a research area that has increased its popularity recently. For security problems or in the advertising sector, age recognition applications with voice have been used. Sound is structurally complex, but it has been seen that it is possible to extract the characteristic features of the sound. The designed system was created without giving any gender information in order to estimate age from human speech. The most popular audio feature extraction methods are Mel-Frequency Cepstrum Coefficient (MFCC) and Perceptual Linear Prediction (PLP) which were used in this study. In addition, Chroma features were also used. This study, it is aimed to get the highest efficiency from the voice features by using different feature extractors and rearranging the dataset according to the feature importance priority. For this purpose, eight age groups were formed from a dataset containing different speakers and so, the MLP (Multi-Layer Perceptron) classification method was used. Mozilla Open-Source Dataset was used in our system, and the highest accuracy rate of age classification was observed as 94.34% being the highest score in the literature. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only A Compact Low SAR Value Circularly Polarized Wearable Antenna Design for 5G Applications(Institute of Electrical and Electronics Engineers Inc., 2022) Gokdemir, Melih; Saeidi, Tale; Karamzadeh, Saeid; Akleman, Funda; Gokdemir, Melih, Department of Electronics and Communication Engineering, İstanbul Teknik Üniversitesi, Istanbul, Turkey; Saeidi, Tale, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Akleman, Funda, Department of Electronics and Communication Engineering, İstanbul Teknik Üniversitesi, Istanbul, TurkeyIn this study, a wideband wearable antenna is proposed for 5G and IoT applications. The presented circularly polarized coplanar waveguide antenna has a compact size (16mm x 21.5mm). The other result of the novel design which makes this antenna one of the best choices for wearable applications is its low SAR values. These values are 0.0846 and 0.0497 W/kg for mass densities of 1g and 10g, respectively. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only A Wearable Circularly Polarized Antenna for 5G Applications, 5G Uygulamalari için Giyilebilir Dairesel Polarizasyonlu Anten(Institute of Electrical and Electronics Engineers Inc., 2022) Ibrahim, Assim; Tetık, Evrim; Karamzadeh, Saeid; Ibrahim, Assim, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Tetık, Evrim, Department of Electrical and Electronic Engineering, İstanbul Arel Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey5G technology for health care is a considerable demand nowadays due to the revolution in IoT devices. A dual-band antenna on a Rogers RT/duroid 5880 substrate with a dielectric constant of 2.2 and thickness of 0.508 mm, is presented for 3.4 GHz and 5.85GHz frequency bands. The top layer of the proposed antenna consists of a square part that includes an inductive meander line. It is connected to an I-shape, which is merged with reversed L-shaped, the higher resonant frequency excited at 3.4 GHz. In the bottom layer, after the reflector is made, the inductive meander line is created and connected to a reversed U-shape. The proposed antenna of size 19 x 12 mm2 reveals to perform well for frequencies between 3.37 and 3.47 GHz. It has an axial ratio less than 3dBi and a peak gain of 1.7 dBi that increases after adding a multi-layer of a human hand up to 8 dBi. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only Metamaterial-Based Circularly Polarized Wearable Antenna for ISM and 5G Communications(Institute of Electrical and Electronics Engineers Inc., 2022) Saeidi, Tale; Gokdemir, Melih; Karamzadeh, Saeid; Saeidi, Tale, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Gokdemir, Melih, Elctronics and Communication Engineering Department, İstanbul Teknik Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA multiband, small, high gain, low specific absorption rate (SAR), and circularly polarized (CP) textile wearable antenna is designed on a layer of denim (ϵr = 1.3, h= 0.787 mm) substrate. The antenna is comprised of a rectangular patch that feeds through an inset transmission line and four tilted periodic slots to enhance the bandwidth (BW) and achieve circular polarization. A layer of fleece fabric (ϵr = 1.04, h= 3 mm) attached to a layer of full ShieldIt to create maximum directivity and minimize SAR value. Then, the antenna is loaded with six arrays of Split Ring Resonator (SRR) on the same antenna layer to enhance the BW that had been reduced after adding the second layer. The antenna works for both ISM and 5G communication systems as it operates at 2.35-2.45 GHz and 3.3-3.9 GHz, respectively. It has the maximum directive gain of 8.52 dBi, acceptable SAR values for both standards with total dimensions of 54 × 56 mm2. In addition, the antenna's CP is examined, showing AR values of < 3 dB at the working BW with a decent agreement between the simulation and measurement outcomes. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only Design and analysis of a label-free water-soluble glucose sensor based on suspended hybrid plasmonic micro-ring resonator(Institute of Electrical and Electronics Engineers Inc., 2022) Moeinimaleki, Kaveh; Moeinimaleki, Babak; Zarean, Rana; Abedashtiani, Alireza; Karamzadeh, Saeid; Moeinimaleki, Kaveh, Department of Research and Development, GraphenePi Company, Istanbul, Turkey; Moeinimaleki, Babak, Department of Research and Development, GraphenePi Company, Istanbul, Turkey; Zarean, Rana, Faculty of Biology, Payame Noor University, Tehran, Iran; Abedashtiani, Alireza, Faculty of Dentistry, Akdeniz Üniversitesi, Antalya, Turkey; Karamzadeh, Saeid, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyIn this paper, the design and analysis of a label-free water-soluble glucose sensor based on a suspended hybrid plasmonic micro-ring resonator with an external radius of 940 nm in the third telecommunication window to sense the concentration of water-soluble glucose is presented. The simulation results obtained using three-dimensional FDTD show that the sensitivity and the figure of merit values obtained for glucose measurements with concentrations of 0 to 50% in water solution are 218.5 (nm/RIU) and 16.11 (1/RIU), respectively. Comparing the results of the proposed sensor with the previous work, which has four times more footprint, shows that the structure's sensitivity has increased by 17 percent. © 2022 Elsevier B.V., All rights reserved.Publication Metadata only X-Band Circularly Polarized Antenna for CubeSat Communication(Institute of Electrical and Electronics Engineers Inc., 2023) Karamzadeh, Saeid; Karamzadeh, Saeid, Intelligent Wireless System, Silicon Austria Labs GmbH, Graz, Austria, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, TurkeyA compact size high gain circularly polarized patch antenna with polarization diversity is presented for CubeSat communication. The antenna has polarization diversity and could support both Right-Hand Circular Polarization (RHCP) and Left-Hand Circular Polarization (LHCP) at the same time. The impedance bandwidth of the antenna is 27% (7.1GHz - 9.4GHz) which is represented by the S11 result. The axial ratio of the proposed antenna is 23% (7.2GHz - 9.1GHZ) and the gain is 5.5 dBic. The radiation pattern of the antenna convenient for CubeSat is also provided. © 2023 Elsevier B.V., All rights reserved.Publication Metadata only Detection of Human Respiratory and Range by IR-UWB Radar(Institute of Electrical and Electronics Engineers Inc., 2023) Shakfa, Ali; Esmaeilishahir, Mahdi; Karamzadeh, Saeid; Shakfa, Ali, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Esmaeilishahir, Mahdi, Department of Electrical and Electronic Engineering, Bahçeşehir Üniversitesi, Istanbul, Turkey; Karamzadeh, Saeid, Intelligent Wireless System, Silicon Austria Labs GmbH, Graz, AustriaThe technology of Impulse Radio Ultra-Wide-Band (IR-UWB) radar is very promising for non-contact sensing applications, such as detecting human vital signs like heart rate (HR) and respiration rate (RR), as well as determining the location of a person. This research paper introduces a technique for detecting the respiration rate and location of a stationary human. The method involves using preprocessing techniques to improve clutter reduction and estimating the frequency domain of the signals. Low pass and bandpass filters as preprocessing methods are presented. The Fast Fourier Transform (FFT) processing method is used to determine the human RR in the frequency domain. The proposed approach is evaluated using a P440 (IR-UWB) radar and shows promising results. The experiments demonstrate that the proposed method is effective in accurately detecting the vital signs of a stationary single or multiple persons. © 2023 Elsevier B.V., All rights reserved.