Yazar "Varshney, Atul" seçeneğine göre listele

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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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    Offset-fed Slotted Antenna Practically Loaded with Split Ring as Water Quality Sensor for X-Band Industrial Applications
    (Advanced Electromagnetics, 2024) Varshney, Atul; Gençoğlan, 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?o×0.467?o×0.053?o, where ?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 (fr), the antenna quality factor with different total dissolved solvents (TDS) in the water samples, and changes in the reflection coefficient (S11) values. It is observed that the antenna shows less than 1.5% numerical sensitivity (NS) with fr, and high NS with the S11. The antenna's S11 and bandwidth vary and depending on the water sample. This antenna is suitable for X-band industrial and microwave laboratory applications. © 2024, Advanced Electromagnetics. All rights reserved.
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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.