Electrical - Electronic Engineering / Elektrik - Elektronik Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/11

Browse

Filters

2016 - 201922020 - 20222

Settings

Has files: YesPublisher: search.filters.publisher.Taylor & Francis

Search Results

Now showing 1 - 4 of 4
  • Article
    Citation - WoS: 3
    Citation - Scopus: 3
    Reconstructions of Effective Parameters for a Metamaterial Antenna Via 3d-Printed Components
    (Taylor & Francis, 2022) Yılmaz, Hasan Önder; Yaman, Fatih
    This study presents the reconstruction of effective medium parameters for a double negative metamaterial slab from the knowledge of the measured/simulated S-matrix. The structure initially has been designed to embed into a patch antenna for a radar application. To observe the medium characteristics, we locate the slab in a rectangular waveguide for various orientations. The waveguide-based retrieval method is applied to find parameters regarding the biaxial anisotropic medium. Fundamental mode is used for the excitation. Additive printing technology is employed to manufacture a rectangular waveguide and its adapters for the experiments. The metallization is achieved by coating the printed structures with conductive thin layers. Experimental setups for each orientation are simulated as well. We illustrate good agreements between simulation and measurements under the fabrication tolerances. The feasibility and applicability of the additive printing technology for the investigations of the metamaterial anisotropic/bianisotropic nature is reported.
  • Article
    Citation - WoS: 4
    Citation - Scopus: 4
    A Symmetrical Self-Diplexing Microstrip Antenna With Eight-Shaped Defects
    (Taylor & Francis, 2022) Karatay, Anıl
    This article aims to demonstrate the simulation and measurement results of a two-port and symmetrical microstrip antenna operating at 6.6 and 7 GHz frequencies. The essential advantages of the antenna in terms of numerical electromagnetism are that the geometry has a small electrical length at both frequencies, does not use a structure that requires extra computational load such as substrate integrated waveguide, and is symmetrical, thus reducing the mesh requirement by half. The proposed antenna was manufactured with the chemical etching method and the measurement results were presented. In addition, varying operating frequencies are shown with the aid of liquid metal to experimentally demonstrate the independent redesign/reconfigurability feature of the antenna. To further reduce the fabrication cost, the manufacturing process of the proposed antenna with the help of a 3D printer is explained, and the performance parameters are compared. Good agreement between simulations and measurements has been reported.
  • Article
    User-Relay Assisted Cellular Networks With Multiple Antennas
    (Taylor & Francis, 2019) Baştürk, İlhan; Özbek, Berna
    User-relay assisted OFDMA-based cellular networks have gained great importance recently since these networks are indicated as one of the powerful technologies that will contribute the 5G standard. These networks can be used with novel three-phase frame structure unlike classical two-phase frame structure and can be enhanced with multiple antennas to utilise the advantages of them. The main advantage of the three-phase frame structure is taking care of the limitations of the current transceiver design in practical systems and not allowing users to be relay and user simultaneously. Diversity and capacity gains are also the advantages of extending the network with multiple antennas. In this paper, we will use the novel three-phase frame structure for downlink MISO-OFDMA cellular networks and develop resource management algorithms as relay selection and resource allocation to observe the benefits of this system.
  • Article
    Citation - WoS: 1
    Citation - Scopus: 1
    Temperature and Pressure Dependence of the Raman Intensity and Frequency of a Soft Mode Near the Tricritical Point in the Ferroelectric Sbsi
    (Taylor & Francis, 2016) Yurtseven, Hasan Hamit; Duman, Sinem
    We analyze the pressure dependence of the intensity and the frequency of a soft mode from the Raman and elastic light scattering experiments as reported in the literature close to the ferroelectric - paraelectric transition in SbSI crystal. The Raman intensity of this mode is analyzed as a function of pressure at constant temperatures of 272K (first order transition) and 234K (tricritical or second order transition) according to a power-law formula. Our analysis of the Raman intensity gives closely the mean field values for the order parameter. From our analysis, we also obtain that the Raman frequency (squared) of the soft mode varies linearly with the pressure at constant temperatures close to the ferroelectric - paraelectric transition in SbSI as obtained experimentally.