Bahadir S. Yildirim

Fatih University, İstanbul, Istanbul, Turkey

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Publications (6)5.31 Total impact

  • Source
    Bedri A. Cetiner · Necmi Biyikli · Bahadir S. Yildirim · Yasin Damgaci
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    ABSTRACT: We report on the full-wave analyses of a frequency reconfigurable antenna integrated with metallic nanoelectromechanical system (NEMS) switches (length = 3 μm, width = 60 nm). The NEMS switch used in this work has the same architecture with low voltage, double-arm cantilever-type metallic DC-contact microelectromechanical system (MEMS) switch recently developed in author's group. The microfabrication and characterization of the MEMS switch have also been given in this article. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 64–69, 2010; Published online in Wiley InterScience ( DOI 10.1002/mop.24833
    Full-text · Article · Jan 2010 · Microwave and Optical Technology Letters
  • Bahadir S. Yildirim · Bedri A. Cetiner · Gemma Roqueta · Luis Jofre
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    ABSTRACT: A small-sized, low-profile, and planar integrated Bluetooth and ultrawideband (UWB) antenna is presented. The antenna exhibits a dual-band operation covering 2400-2484 MHz (Bluetooth) and 3100-10600 MHz (UWB) frequency bands. It is fed by a microstrip line and built on a FR-4 substrate with 42times46 mm<sup>2</sup> surface area. The impedance, radiation, phase linearity, and impulse response properties of the antenna are studied both theoretically and experimentally. The calculated and measured results agree well. The antenna shows acceptable gain flatness with stable omnidirectional radiation patterns across the integrated Bluetooth and UWB bands. The average group delay is approximately 0.2 ns across UWB frequencies. The impulse response is very good, with some level of ringing observed.
    No preview · Article · Feb 2009 · IEEE Antennas and Wireless Propagation Letters
  • B. Yildirim · A. Genc · B.A. Cetiner
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    ABSTRACT: This paper presents a microstrip-fed integrated bluetooth and ultra-wide band (UWB) antenna that is small, low-profile, and planar. Antenna occupies an area of 42 times 46 (mm) on a printed circuit board (PCB). The design of the antenna is optimized to provide high performance for the operation at 3100-10600 MHz (UWB) and 2400-2484 MHz (bluetooth) bands. The antenna was fabricated and its return loss and radiation patterns were measured and compared to the simulations results showing a good agreement between theoretical and measured results.
    No preview · Conference Paper · Jul 2008
  • Bahadir Yildirim · Bedri A. Cetiner
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    ABSTRACT: A new method to increase the gain of a conventional microstrip patch antenna is presented. A rectangular loop shaped parasitic radiator placed a specific distance away from the patch surface increases the gain by about 3.3 dB. The impedance and radiation performances of the proposed antenna are presented with excellent agreement between simulated and measured results.
    No preview · Article · Feb 2008 · IEEE Antennas and Wireless Propagation Letters
  • Bahadir Yildirim · Bedri Cetiner · Qingzhou Xu
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    ABSTRACT: A reconfigurable penta-band (GSM900, GPS 1575, GSM1800, PCS 1900, UMTS2100) planar inverted-F antenna (PIFA) having microelectromechanical switches (MEMS) is designed. A number of RF MEMS actuators within the geometrical structure of the antenna are constructed as part of the design. The antenna is first analyzed using a full-wave electromagnetic simulator and the results are presented. Microfabrication and measurements are currently under progress.
    No preview · Conference Paper · Jul 2007
  • Bahadir S. Yildirim
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    ABSTRACT: This letter presents a microstrip-fed antenna that is small, low-profile, planar, and suitable for WLAN/Bluetooth and ultrawideband (UWB) applications. The antenna occupies an area of 16times18 (mm) on a printed circuit board (PCB) and exhibits dual-band operation at 2400-2484 MHz (Bluetooth) and 5150-5825 MHz (IEEE 802.11a and HiperLAN/2) bands with satisfactory radiation properties. The 10-dB return loss bandwidth of the antenna at high-band spans from about 4.5 GHz to about 11 GHz
    No preview · Article · Jan 2007 · IEEE Antennas and Wireless Propagation Letters