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  • Küçük Resim Yok
    Öğe
    Radiation pattern reconfigurable cubical antenna array for 2.45 GHz wireless communication applications
    (Springer, 2023) Alkurt, Fatih Ozkan; Unal, Emin; Palandoken, Merih; Abdulkarim, Yadgar, I; Hasar, Ugur Cem; Karaaslan, Muharrem
    In this paper a single-fed four-faced multidirectional compact antenna is introduced for 2.45 GHz indoor wireless applications. Firstly, a slotted patch antenna is designed to operate at 2.45 GHz and its equivalent circuit model is synthesized, and then 2 x 1 patch antenna arrays are modelled and placed over the four faces of a cube structure and the final cube antenna is called as 4 x 2 x 1 antenna array. Meanwhile, a 50 omega fed line is positioned at the bottom of this cube with a power dividing network for the feeding line. For this purpose, a T-junction power divider network is designed at the bottom layer of the cube structure. Besides, the RF switches are located at each arm of four faces to transfer microwave energy selectively to each individual antenna element. Therefore, the reflection and radiation characteristics of proposed compact antenna are analysed to improve the performance under various switching conditions by the numerical analysis. The possibility of controlling selective radiation in a given direction is confirmed. The main advantage of the proposed design is to have capability of radiation control while preserving the reflection coefficient stability by RF switches. Finally, the proposed compact antenna is fabricated using a conventional printed circuit technology and the radiation performance is tested by the experimental measurements conducted. It is observed that measurement results are in a good agreement with the numerical computation results.
  • Küçük Resim Yok
    Öğe
    A study on electronically controllable beamforming monopole antenna for telecommunication applications
    (Taylor & Francis Ltd, 2023) Alkurt, Fatih Ozkan; Unal, Emin; Palandoken, Merih; Altintarla, Gizem; Abdulkarim, Yadgar I.; Hasar, Ugur Cem; Karaaslan, Muharrem
    The design, analysis, and prototyping of an electronically controllable beamforming monopole antenna (ECBMA), which could be a good candidate for ceil-mounted wireless telecommunication systems, are reported. The proposed ECBMA targeting the 2.45 GHz center frequency is based on the 'on-off' ground reflectors, which are connected to the main ground layer by twelve RF switches to implement digital logic states. There are twelve ground reflectors symmetrically positioned over azimuthal angle direction in the ECBMA structure controlled by RF switches and a microcontroller unit, thus resulting in a pattern change when the states of the switches change logically. The designed ECBMA has the following three main features. First, it has a good and stable reflection coefficient (S11) characteristic at the 2.45 GHz centre frequency. Second, it has a wideband characteristic between 2.15 and 2.85 GHz (700 MHz operational bandwidth). Third, it has the capability to create single, double, or multi-beam characteristics (multi-purpose) which is a highly desired feature in many modern wireless communication systems mainly suitable for indoor applications. The prototype of our ECBMA is fabricated, and the performance analysis is investigated experimentally and S11 and radiation characteristics have good performance and are in good agreement with the simulation results. The proposed ECBMA has a good candidate for wireless telecommunication purposes such as WLAN, ISM, Wi-Fi, Bluetooth and other RF peripherals like indoor applications.