Browsing by Author "Asci, Yavuz"

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Citation - WoS: 1
Dual Band Cavity-Backed Filtering Antenna with Modified Coupling Slot Structure
(IEEE, 2024) Yavuz Asci; Mustafa Secmen; Asci, Yavuz; Secmen, Mustafa
In this study the loading stub technique is proposed to convert a wideband 2 x 2 full metal cavity-backed antenna into a dual band antenna for satellite communication (SatCom) systems. A wideband 2 x 2 cavity-backed antenna is converted to a dual-band antenna by simply adding stubs to the conventional coupling slot structure which act as a filter. The filtering antenna does not change the wideband antenna's lateral and longitudinal dimensions and does not distort gain and radiation characteristics within in-band frequency regions. By integrating these stubs the undesired frequency band of 12.5 - 13.75 GHz between Rx (10.7 - 12.5 GHz) and Tx (13.75 - 14.5 GHz) in-bands at Ku-band is effectively suppressed which improves isolation and lowers interference. The simulated fractional bandwidths (FBW) for vertical bar S-11 vertical bar <-10 dB are 15.78% (10.68 - 12.51 GHz) and 8.1% (13.74 - 14.9 GHz) at the Rx and Tx bands respectively. The peak gain values range from 13.06 to 13.92 dBi at Rx and 13.57 to 14.24 dBi at Tx bands. Besides the out-of-band rejection level reaches 20.7 dB at 13 GHz while covering the entire Rx and Tx bands of the Ku-band.
Citation - Scopus: 2
Dual-Band 2×2 Cavity-Backed Antenna with Enhanced Out-of-Band Suppression for Tx/Rx Communication of UAVs at Ku-Band
(Institute of Electrical and Electronics Engineers Inc., 2023) Yavuz Asci; Mustafa Seçmen; Asci, Yavuz; Secmen, Mustafa
This study introduces a dual-band linearly polarized 2×2 element cavity-backed antenna for unmanned aerial vehicles (UAVs). The proposed antenna can cover entire Rx (10.512.5 GHz) and Tx (13.7514.5 GHz) bands of Satcom and datalink operations at Ku-band. The radiating part of the antenna contains four (2×2) radiating slots which are excited by a coupling slot at the end of the feeding waveguide and a 2×2 cavity power divider. Additional baffles placed between radiating slots at the aperture are used to increase the bandwidth and gain values of in-band and slightly improve out-of-band suppression. The antenna is fed by a rectangular waveguide which includes two third-order E-plane band-stop filters being placed on the opposite sides of broad wall of the waveguide to significantly suppress out-of-band frequencies between Tx/Rx bands and below Rx band which gives dual-band characteristics. The proposed full metal antenna has Rx and Tx bandwidths of 10.3612.54 GHz (|S11|< -10 dB, FBW = 16%) and 13.6314.7 GHz (|S11|< -10 dB, FBW = 7%) respectively. It has peak gain of 14.3 dBi with a stable in-band gain of 14.15 ± 0.15 dBi. Out-of-band rejection level of above 20 dB is obtained at the undesired bands of 9.810 GHz and 12.813.2 GHz. © 2024 Elsevier B.V. All rights reserved.
Dual-band full metal 2 × 2 cavity-backed filtering antenna with waveguide stubs on coupling slot
(Institute of Physics, 2025) Yavuz Asci; Mustafa Seçmen; Asci, Yavuz; Secmen, Mustafa
In this study a dual-band full metal cavity-backed antenna which has been modified from a wideband antenna is presented for a Ku-band satellite communication systems (SatCom). The antenna consists of a feed waveguide coupling slot cavity-backed power division layer and radiating layer with slots and baffles. For filtering purposes the stubs are inserted into the coupling slot which provides notches. They are intended to separate the Rx and Tx bands. This converts a wideband antenna into a dual-band antenna without changing the overall dimensions of the antenna. Moreover gain/radiation patterns in the Tx and Rx bands are not affected. The addition of stubs effectively rejects the out-of-band frequency region of 12.5-13.75 GHz between receive (Rx, 10.5-12.5 GHz) and transmit (Tx, 13.75-14.5 GHz) bands. Consequently isolation and interference between the Rx and Tx bands is improved. The measured S-parameters for |S11| < −10 dB present the bandwidths of 2.18 GHz (10.42-12.6 GHz FBW = 18.9%) and 0.87 GHz (13.83-14.7 GHz GHz FBW = 6.1%) for Rx and Tx bands respectively. Besides the bandwidth of |S11| > −2 dB for the out-of-band region is 0.57 GHz (12.95-13.52 GHz) which gives dual-band characteristics. The measured peak gain of the antenna is about 14.9 dBi. The maximum out-of-band rejection between the Rx and Tx bands is about 19.2 dB at 13 GHz. The proposed antenna has compact dimensions of 1.7λ0 × 1.5λ0 × 1λ0 at the lowest frequency of 10.4 GHz. © 2025 Elsevier B.V. All rights reserved.
Citation - Scopus: 1
Wideband Omnidirectional Coplanar Waveguide-Fed Coaxial Dipole Antenna for VHF/UHF Communication Bands with Improved XPD
(Institute of Electrical and Electronics Engineers Inc., 2023) Yavuz Asci; Mustafa Seçmen; Mehmet Altuntas; Asci, Yavuz; Secmen, Mustafa; Altuntas, Mehmet
In this study a blended coplanar waveguide-fed (BCPWF) coaxial dipole antenna with improved cross-polarization discrimination (XPD) is proposed. The proposed antenna composes of a BCWF a metal cone and two stacked tubular metal cylinders. By blending CPWF the effects of the current flowing through the top surface of CPWF can be minimized. This results in low XPD and wideband omnidirectional characteristics. The effects of blend radius and thickness of CPWF on bandwidth and XPD are investigated. Besides ferrite material is utilized in the connector side to eliminate leakage currents at low frequencies. The effects of the ferrite material on the radiation pattern and VSWR are demonstrated for long cable applications. The proposed antenna operates 99-1202 MHz (VSWR <2.15, 169.8%) and has 0.48λ × 0.04 λ transverse dimensions. The peak gain of the proposed antenna is 6 dBi. The azimuth (H-plane) gain ranges from -1 dBi to 1.5 dBi for Airband (108-137 MHz) and Mode-S/ADB(800-1100 MHz) communication bands. Due to its wideband omnidirectional easy manufacturing and low-cost properties the proposed antenna can be used in high-tower vehicle shipboard and air traffic control platforms in the VHF/UHF band. © 2024 Elsevier B.V. All rights reserved.