Yazar "Gencoglan, Duygu Nazan" seçeneğine göre listele

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    A compact hybrid reconfigurable antenna using two PIN diodes for C band (4-8 GHZ) applications
    (IOP Publishing Ltd, 2025) Iyikan, Mustafa Can; Gencoglan, Duygu Nazan
    This study presents a compact and high-performance hybrid reconfigurable antenna capable of both frequency and radiation pattern reconfiguration using only two PIN diodes integrated with a bias tee circuit. Designed for C-band applications, the antenna occupies a miniaturized footprint of 15 x 23 x 1.6 mm3 and is fabricated on an FR-4 substrate (epsilon r = 4.4, tan delta = 0.02). It consists of a rectangular monopole radiator and two parasitic elements, whose connectivity is controlled through diode switching to achieve dynamic reconfigurability. The antenna supports five distinct resonance frequencies across four switching states ( 00, 01, 10, and 11), covering 4.5 GHz to 7.83 GHz, and enables multiple radiation pattern configurations. These resonance frequencies are at 6.26 GHz( Case 1-00), 5.53 GHz ( Case 2- 01), 4.9 & 7.67 GHz( Case 3-10), and 5 GHz ( Case 4-11), respectively. The integrated bias tee ensures effective RF/DC isolation and low insertion loss, enhancing switching performance and addressing a common limitation in previous designs. Simulated and measured results show strong agreement, with reflection coefficients below -15 dB and peak values reaching -40 dB. The antenna achieves radiation efficiencies between 81% and 92.4% and gain values from 1.93 to 3.61 dBi. Compared to state-of-the-art designs, this antenna offers superior miniaturization, fewer switches, broader reconfigurability, and practical biasing integration, which makes it well-suited for compact, energy-efficient, and adaptive wireless communication systems.
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    ANFIS-SA-based design of a hybrid reconfigurable antenna for L-Band, C-band, 5G and ISM band applications
    (Pergamon-Elsevier Science Ltd, 2025) Gencoglan, Duygu Nazan
    This study presents a novel hybrid reconfigurable antenna design optimized using an Adaptive Neuro-Fuzzy Inference System (ANFIS) enhanced with a Simulated Annealing (SA) algorithm for L-band, C-band, 5G, and ISM applications. The antenna is fabricated on an FR-4 substrate with dimensions of 17 x 28 x 1.6 mm3, and two PIN diodes are employed to achieve frequency and radiation pattern reconfigurability. In the ON-ON state, the antenna operates in dual bands, covering 1.33-1.38 GHz (L-band) and 3.57-3.95 GHz (C-band). For the OFF-ON state, it operates from 3.56 to 3.95 GHz (C-band, 5G). In the ON-OFF state, it covers 1.50-1.54 GHz (L-band) and 5.66-5.90 GHz (ISM band), while in the OFF-OFF state, it operates from 5.49 to 5.82 GHz (ISM band). The antenna exhibits common bands at 3.8 GHz (C-band) and 5.8 GHz (ISM) across different states, facilitating pattern reconfigurability. ANFIS-SA is applied to optimize the switch locations, significantly improving resonance frequency and S11 performance. The antenna supports beam steering between 0 degrees and 180 degrees, enhancing adaptive coverage for modern applications such as Wi-Fi, Vehicle-to-Vehicle (V2 V), and Vehicle-to-Infrastructure (V2I) communication. This study addresses a critical gap by combining hybrid optimization techniques to improve frequency agility and radiation pattern control for next-generation wireless systems.
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    Bio-inspired Spider-Shaped Antenna with Frequency and Gain Reconfigurability for 5G and Emerging Lower 6G Bands
    (Springer Heidelberg, 2025) Varshney, Atul; Gencoglan, Duygu Nazan
    This paper presents a novel, compact, bioinspired spider-shaped reconfigurable antenna designed for multi-band wireless applications spanning the S-band, C-band, 5G sub-6 GHz, and emerging 6G bands (7.125-8.40 GHz). Recent frequency-reconfigurable antennas often rely on multiple PIN diodes, stacked substrates, or complex tuning networks, leading to increased size, cost, and fabrication complexity. Many designs also prioritize frequency tunability while overlooking gain enhancement, limiting their effectiveness in long-range, high-data-rate scenarios. Furthermore, most reported antennas do not address the critical intermediate 6G band (7.125-8.40 GHz), and high-performance designs commonly use costly substrates like Rogers RT5880, making them unsuitable for mass deployment. The key challenges faced in designing this include maintaining radiation efficiency in a miniaturized spider-shaped geometry, achieving stable ON/OFF switching with a single PIN diode (BAR64-02V), mitigating dielectric dispersion losses on FR-4 at higher frequencies, and ensuring reliable multi-band operation in a low-cost structure. To address these issues, a novel slotted-fractal and filleted design (developed from a circular patch to a spider-shaped) antenna was fabricated on an FR-4 substrate. The antenna dynamically tunes frequency and gain by controlling current paths via a single RF switch. In measurements, it achieves 4.64 dBi gain at 3.58 GHz (no diode), enhanced to 9.03 dBi in the diode's ON state, and doubles the upper-band bandwidth from 1.43 to 2.86 GHz in the OFF state. The design realizes a 43.25% size reduction and exhibits excellent agreement between measured and simulated performance, offering a cost-effective and scalable solution for future wireless systems.
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    Characterizations of Effective Parameters and Circuit Modeling of U-Coupled Hybrid Ring Resonator Band Pass Filter
    (IEEE-Inst Electrical Electronics Engineers Inc, 2025) Varshney, Atul; Gencoglan, Duygu Nazan; Elfergani, Issa; Rodriguez, Jonathan; Zebiri, Chemseddine; Neebha, T. Mary
    A two-port symmetrical, reciprocal, U-shaped mutually coupled hybrid ring resonator for ISM, L-band, and S-band applications is presented. The designed resonator is novel with a hybrid ring which comprises a square ring, a circular ring, and two U-shaped couplers for effective mutual coupling between rings and microstrip feeds. The proposed resonator serves as a bandpass filter with a passband ranging from 1.31 GHz to 2.68 GHz. This design offers superior performance compared to conventional ring resonators. The equivalent circuit model of the hybrid ring resonator validated the behavior of the filtering action. The resonator is validated using the measurement of reflection and transmission coefficients. The comparisons of measured values of the prototyped resonator model with CST-designed and HFSS-designed simulated values are found in good agreement in terms of design frequency 2.45 GHz, reflection and transmission coefficient values, and -10 dB bandwidth values. The equivalent circuit model is validated using ADS software. The designed circuit parameter values are found to be in excellent match with manually evaluated circuit parameters with tolerances under +/- 20%. Selectivity of the ring resonator is investigated for applicability of proposed resonator filter for practical applications. The hybrid resonator is good for the measurement of dielectric permittivity and loss tangent estimations at any frequency without the need for a calculator. The effective parameters are evaluated for characterizations of dielectric properties and their behavior as metamaterials. These attributes make the proposed hybrid ring resonator a highly versatile and efficient solution for next generation communication devices and applications.
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    Compact metasurface antenna for Sub-6 GHz applications with isolated n77/n78 bands using CSRR
    (IOP Publishing Ltd, 2025) Varshney, Atul; Kumar, Satyam; Gencoglan, Duygu Nazan; Tiwari, Satyam; Ara, Shabnam; Elfergani, Issa; Zebiri, Chemseddine; Rodriguez, Jonathan
    A compact (0.35 lambda 0 x 0.35 lambda 0 where lambda 0 is free space wavelength at the lower resonance frequency 3.50 GHz) bio-inspired tulip flower-shaped antenna (TFSA) is proposed. A double negative (DNG) metamaterial complementary split ring resonator (CSRR) is introduced near the feed in the hybrid triangular-circular patch which inserts a notch-band (4.20-4.38 GHz) in the wide bandwidth (3.15-7.05 GHz) and makes the antenna response dual-band. Consequently, this results in in-band interference reduction in 5G-Sub-6 GHz applications. A slotted FSS is placed at a distance of 28.507 mm beneath the monopole-reduced ground of the antenna to enhance the reduced gain from 4.39 dBi to 7.22 dBi. A further gain is improved to 12.84 dBi by placing a full copper surface (0.35 lambda 0 x 0.35 lambda 0 ) as the reflector layer is placed below FSS at 1.6 mm. Finally, prototyped TFSA with FSS and reflector model achieve a dual bands reflection coefficient response (3.15-4.20 GHz): n77/n78, and (4.38-7.03 GHz): n46/n47/n96/n102/n79. The antenna reflection coefficient is tested using Keysight 14 GHz FieldFox Microwave Analyzer N9916A, and radiation patterns in the E-plane and H-plane are measured using an 18 GHz anechoic chamber. The comparison of simulated results with measured results is found an excellent match in bandwidth and with shapes of gain radiation patterns. The reflector and FSS jointly make the radiation pattern strong in the E-plane above the TFSA radiator. The antenna is well suited for n77/n78 (3.30-4.20 GHz), n79(4.40-4.99 GHz), n46 (5150-5925 MHz), n47 (5855-5925 MHz), n96/n102 (5925-6425 MHz), 5.8 GHz HiperLAN, WiMAX 3.5 GHz applications. An electrical equivalent circuit model of the proposed TFSA antenna is presented and validated using ADS software.
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    Gain and bandwidth enhancement using superstrate loaded 2x2 circular-array antenna for X-Band and RADAR applications
    (Taylor & Francis Ltd, 2024) Varshney, Atul; Gencoglan, Duygu Nazan
    This article demonstrates the fabrication, and measurements of a corporate offset-fed 2 x 2 array electromagnetically coupled patch (EMCP) circular-antenna based on the Fabry-Perot cavity principle. Single element antenna has a low gain of 6.28 dBi and is enhanced to 13.45dBi by loading the array with a superstrate. The antenna parameters -10 dB fractional bandwidth (FBW) and gain are improved by an air gap with 4-stacked circular patches and 4 stubs in the proposed design. The peak gain of the 2 x 2 array without superstrate was 8.88 dBi at 8.19 GHz, which is enhanced to 13.82 dBi at 9.55 GHz by parasitic loading and superstrate. The FBW of the proposed array antenna was enhanced by arranging four stubs between the 4-circles in the superstrate structure. The -10 dB FBW without stubs was 24.82% (7.62-9.73 GHz) and with stubs it became 38.47% (7.73-11.0 GHz). Adjustment of the height of the superstrate at 2.0 mm not only enhanced the gain and bandwidth but also advancement in the unidirectional radiation patterns. The array is prototyped is measured to validate the reflection coefficients and radiation characteristics and they found an excellent match with simulated results. The suggested array is most suitable for energy launchers in transitions, RADAR, military, satellite, X-band communications, and microwave laboratory applications.
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    High-Gain Multi-Band Koch Fractal FSS Antenna for Sub-6 GHz Applications
    (Mdpi, 2024) Varshney, Atul; Gencoglan, Duygu Nazan
    Featured Application The proposed antenna is potentially suitable for Wi-MAX (3.5 GHz) and sub-6 GHz n77 (3300-3800 MHz), n78 (3300-4200 MHz), and n79 (4400-4990 MHz), in addition to C-band applications.Abstract This study introduces a novel antenna based on the binary operation of a modified circular patch in conjunction with the Koch fractal. The antenna is intended for applications in the sub-6 GHz band, partial C-band, and X-band. The low-cost antenna is fabricated on a 1.6-mm-thick FR-4 substrate. A frequency-selective surface (FSS) is used to overcome the decreased values of the gain and bandwidth due to the fractal operations. The introduced split ring resonator (SRR) and the antenna substrate dimension reduction reduce the bandwidth and antenna gain. The air gap between the FSS and the antenna not only enhances the antenna gain but also controls the frequency tuning at the design frequency. The antenna size is miniaturized to 36.67%. A monopole antenna ground loaded with an SRR results in improved closest tuning (3.44 GHz) near the design frequency. The antenna achieves a peak gain of 9.37 dBi in this band. The FSS-based antenna results in a 4.65 dBi improvement in the gain value with the FSS. The measured and simulated plots exhibit an excellent match with each other in all three frequency bands at 2.96-4.72 GHz. These bands cover Wi-MAX (3.5 GHz), sub-6 GHz n77 (3300-3800 MHz), n78 (3300-4200 MHz), and approximately n79 (4400-4990 MHz), in addition to C-band applications.
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    Improvement of Bowtie Antenna Parameters for Ultra - Wide Band Applications
    (IEEE, 2016) Colak, Sule; Gencoglan, Duygu Nazan
    In this study, bowtie antenna is designed for Ultra- Wide Band (UWB) communication applications, and radiation characteristics of the antenna in these systems are investigated by observing the behavior of parameters such as radiation pattern, return loss (S-11), and voltage standing wave ratio (VSWR). Additionally, in order to improve antenna performance in the UWB frequency range, parameters such as flare angle, substrate thickness and relative dielectric constant are changed to obtain antenna structure with the best performance. CST Microwave Studio is used for the design and modeling of the antenna.
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    Improvement of bowtie antenna parameters for Ultra - Wide Band applications
    (Institute of Electrical and Electronics Engineers Inc., 2016) Colak, Sule; Gencoglan, Duygu Nazan
    In this study, bowtie antenna is designed for Ultra-Wide Band (UWB) communication applications, and radiation characteristics of the antenna in these systems are investigated by observing the behavior of parameters such as radiation pattern, return loss (S11), and voltage standing wave ratio (VSWR). Additionally, in order to improve antenna performance in the UWB frequency range, parameters such as flare angle, substrate thickness and relative dielectric constant are changed to obtain antenna structure with the best performance. CST Microwave Studio is used for the design and modeling of the antenna. © 2016 IEEE.
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    Novel Frequency-Reconfigurable Antennas with Ring Resonators and RF Switches: Enhancing Versatility and Adaptability in Wireless Communication Systems
    (Mdpi, 2023) Gencoglan, Duygu Nazan; Palandoken, Merih; Colak, Sule
    This study introduces innovative designs for frequency-reconfigurable antennas that utilize ring resonators combined with either PIN diodes or RF switches. These designs enhance the versatility, adaptability, and overall performance of the antennas in wireless communication systems. By controlling the switches and ring resonator, the antenna's resonant frequencies and bandwidths can be adjusted, allowing for compatibility with various communication standards and frequency ranges. The proposed antenna exhibits four distinct operational states, each characterized by different resonance frequencies and operating frequency bands. Return loss, radiation pattern, radiation efficiency, and surface current distribution are analyzed for each state. State-1 (ON-ON) and State-2 (OFF-ON), which are characterized by resonance frequencies of 2.4 GHz and 3.33 GHz respectively, offer ranges suitable for Wi-Fi, Bluetooth, ISM, and IoT applications. State-3 (ON-OFF), with a resonance frequency of 3.0 GHz and bandwidth spanning from 2.59 GHz to 3.643 GHz, complies with Wi-Fi, Wi-Fi 6, and IoT requirements. State-4 (OFF-OFF) covers the band centered around 3.45 GHz. It is compatible with many applications such as 5G mid-band, Wi-Fi 6E, IoT, and cellular systems. The proposed antenna designs are versatile and compact since the overall antenna dimensions are 25 x 18 x 1.6 mm(3). The radiation efficiency of the antenna configuration varies depending on operational states. By utilizing the advantages of both ring resonators and RF switches, the proposed antenna configurations offer new solutions that enhance their performance in wireless communication systems. This study compares the effects of using PIN diodes and SPDT switches on the performance of antennas and also examines the DC biasing effect on antenna characteristics. The simulation results are validated by the experimental analysis. The proposed antenna designs offer a new approach for wireless communication systems by using both ring resonators and RF switches.
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    Offset-fed Slotted Antenna Practically Loaded with Split Ring as Water Quality Sensor for XBand Industrial Applications
    (Advanced Electromagnetics, Geeps-Supelec, 2024) Varshney, Atul; Gencoglan, Duygu Nazan
    This article describes the design, testing, and analysis of an offset-fed split ring-loaded slotted antenna for various water quality sensors. The antenna is designed to resonate at 10 GHz on a low-cost FR-4 substrate of dimensions 0.621 lambda(o)x0.467 lambda(o)x0.053 lambda(o) , where lambda(o) is the free space wavelength at the resonant frequency. The fabricated antenna finds excellent agreement with the measured antenna parameters. At 10 GHz, the antenna achieves a gain of 7.61 dBi, a nearly unidirectional radiation pattern, and a radiation efficiency of 76%. The research is further explored to use the antenna as a water sample sensor. The antenna is tested on various water samples by submerging it in them, and in the second scenario, contactless measurements at 10 mm away from the container's upper water level. The work examines the quality of the water by observing the shift in the resonant frequency (f(r)), the antenna quality factor with different total dissolved solvents (TDS) in the water samples, and changes in the reflection coefficient (S-11) values. It is observed that the antenna shows less than 1.5% numerical sensitivity (NS) with f(r), and high NS with the S-11. The antenna's S 11 and bandwidth vary and depending on the water sample. This antenna is suitable for Xband industrial and microwave laboratory applications.
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    Spiral-Resonator-Based Frequency Reconfigurable Antenna Design for Sub-6 GHz Applications
    (Mdpi, 2023) Gencoglan, Duygu Nazan; colak, Sule; Palandoken, Merih
    This paper presents a novel frequency reconfigurable antenna design for sub-6 GHz applications, featuring a unique combination of antenna elements and control mechanisms. The antenna is composed of an outer split-ring resonator loaded with an inner spiral resonator, which can be adjusted through the remote control of PIN diode or Single Pole Double Throw (SPDT) switches. The compact antenna, measuring 22 x 16 x 1.6 mm(3), operates in broadband, or tri-band mode depending on the ON/OFF states of switches. The frequency reconfigurability is achieved using two BAR64-02V PIN diodes or two CG2415M6 SPDT switches acting as RF switches. SPDT switches are controlled remotely via Arduino unit. Additionally, the antenna demonstrates an omni-directional radiation pattern, making it suitable for wireless communication systems. Experimental results on an FR-4 substrate validate the numerical calculations, confirming the antenna's performance and superiority over existing alternatives in terms of compactness, wide operating frequency range, and cost-effectiveness. The proposed design holds significant potential for applications in Wi-Fi (IEEE 802.11 a/n/ac), Bluetooth (5 GHz), ISM (5 GHz), 3G (UMTS), 4G (LTE), wireless backhaul (4G and 5G networks), WLAN (IEEE 802.11 a/n/ac/ax), 5G NR n1 band, and Wi-Fi access points due to its small size and easy control mechanism. The antenna can be integrated into various devices, including access points, gateways, smartphones, and IoT kits. This novel frequency reconfigurable antenna design presents a valuable contribution to the field, paving the way for further advancements in wireless communication systems.
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    Ultra-Wideband (UWB) characteristic estimation of elliptic patch antenna based on machine learning techniques
    (Walter De Gruyter Gmbh, 2020) Gencoglan, Duygu Nazan; Arslan, Mustafa Turan; Colak, Sule; Yildirim, Esen
    In this study, estimation of Ultra-Wideband (UWB) characteristics of microstrip elliptic patch antenna is investigated by means of k-nearest neighborhood algorithm. A total of 16,940 antennas are simulated by changing antenna dimensions and substrate material. Antennas are examined by observing Return Loss and Voltage Standing Wave Ratio (VSWR) characteristics. In the study, classification of antennas in terms of having UWB characteristics results in accuracies higher than 97%. Additionally, Consistency based Feature Selection method is applied to eliminate redundant and irrelevant features. This method yields that substrate material does not affect the UWB characteristics of the antenna. Classification process is repeated for the reduced feature set, reaching to 97.44% accuracy rate. This result is validated by 854 antennas, which are not included in the original antenna set. Antennas are designed for seven different substrate materials keeping all other parameters constant. Computer Simulation Technology Microwave Studio (CST MWS) is used for the design and simulation of the antennas.