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Mehmet Bamanc&#x; Muharrem Karaaslan Emin Unal Melikah
zaktürk Oguzhan Akgol Faruk Karada Avanish Bhadauria Mehmet Bak&#x;r 《国际射频与微波计算机辅助工程杂志》2019,29(7)
In this article, a novel wide band polarization and incident angle independent metamaterial absorber (MA) and energy harvesting applications which operates at C (4GHz‐8 GHz) and X (8GHz‐12 GHz) is proposed. The unit‐cell of the proposed structure based on fractal circle loop. Four lumped resistors are mounted the structure to obtain a broad band absorption characteristics. Resistors increase the absorption characteristic of proposed MA significantly at mentioned frequency ranges. In addition, under favor of the resistors proposed MA can convert absorbed energy from incident wave to appearing power. 相似文献
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In this work, a step impedance resonator (SIR)‐based structure is proposed to develop a compact tunable metamaterial (MTM)‐based perfect absorber for solar cell applications. This MTM absorber is able to improve the absorption over a wide range of visible frequency range from 550 to 650 THz. The absorption is high around the frequency 600 THz. The proposed model is designed based on SIR technique to achieve miniaturization. The parametric study of overall size of the proposed MTM absorber analyzed over the frequency range 430‐750 THz. The thickness of dielectric spacer, and top most layer (MTM Structure) illustrates the tunable characteristics of the proposed model. A complete comparative analysis of proposed model with different dielectric spacers like AlGaAs, InAs, GaAs, and AlAs are presented with the help of absorption (S11) and transmission (S12). The proposed model is suitable for high efficiency solar cell energy harvesting applications. 相似文献
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Mehmet Bamanc&#x; Ouzhan Akgl Melikah
zaktürk Muharrem Karaaslan Emin Ünal Mehmet Bak&#x;r 《国际射频与微波计算机辅助工程杂志》2019,29(1)
A new polarization independent broadband metamaterial absorber (MA) structure based on split ring resonators which are loaded with lumped elements and via connection lines is proposed. The designed structure shows a perfect absorption between 4 and 16 GHz which is validated by simulation studies. Experimental study is only made for the structure that has no via connections and no the lumped element resistors to show the importance of these entities in the proposed metamaterial structure. Both numerical and experimental study results show that broadband MA property depends on the resistors and via connections on the proposed structure. By having high absorption in a wideband range which is numerically demonstrated, the proposed structure can be used in energy harvesting or wireless power transfer applications with higher efficiencies. 相似文献
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Sachin Kalraiya Mohammad Ameen Raghvendra Kumar Chaudhary Ravi Kumar Gangwar 《国际射频与微波计算机辅助工程杂志》2019,29(12)
A compact, ultrathin conformal metamaterial dual‐band absorber for curved surfaces has been presented in this article. The absorber unit cell composed of circular and split ring resonators which are connected with plus‐shaped structure. The proposed absorber unit cell is compact in size (0.22λo × 0.22λo) and as well as ultrathin thickness (0.006λo), where λo is the wavelength at 5.8 GHz. The designed absorber gives two absorption tips at 5.8 and 7.7 GHz with more than 90% absorptivity. The full width at half maximum bandwidths are 220 MHz (5.67‐5.89 GHz) and 250 MHz (7.58‐7.83 GHz). The proposed conformal absorber is sensitive to the polarization angle and has a stable absorptivity over a wide range of incident electromagnetic wave. The parametric analysis and equivalent transmission line model have been investigated. The surface current and electric field distribution also discussed for understanding the absorption mechanism. To analyze the performance of proposed absorber on the curved surfaces, it is wrapped on the different radius of cylindrical surface and measured the absorptivity. Simulated and measured results have good agreement between them. 相似文献
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In this study, we propose a photoexcited tristate terahertz metamaterial absorber which can switch between single‐/single‐/dual‐band absorption modes in terahertz regime. The unit cell of the absorber incorporates two kinds of photosensitive semiconductor materials filled the gaps between four asymmetric right‐angle wires and a cross wire. By applying different wavelengths of pump light on the absorber, two kinds of semiconductor materials can be excited to realize single‐/single‐/dual‐band switchable absorption characteristics. The distributions of electric fields and surface currents at absorption peak frequencies under three absorption states are demonstrated to elucidate the switchable mechanism of the proposed absorber. Moreover, the absorption performance of the proposed tristate absorber is discussed under different polarization and incidence angles. The proposed structure is expected to be applied in the terahertz devices such as tunable absorbers, modulators, filters, and switches. 相似文献
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In this article, a metamaterial inspired microwave absorber is used to reduce the cross‐polarization (XP) level of the radiated wave in microstrip antenna (MSA). A microwave absorber unit‐cell has been analyzed and implemented to reduce the cross polarization (XP) level in a single element and a 2 × 2 microstrip patch array antennas. The antennas have been designed on a FR‐4 substrate of thickness 0.8 mm at 10.1 GHz center frequency. The 2 × 2 patch array antenna with and without the absorbers have been experimentally verified for the S11 parameter, the radiation pattern, and the XP suppression in H‐plane and a good comparison has been found. 相似文献
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Zhiping Yin Yujiao Lu Sheng Gao Jun Yang Weien Lai Zelun Li Guangsheng Deng 《国际射频与微波计算机辅助工程杂志》2019,29(2)
This article proposes and experimentally demonstrates an optically transparent and polarization‐insensitive metamaterial absorber in the terahertz (THz) frequencies. The absorber is formed by indium‐tin‐oxide (ITO) resistive films, providing efficient absorption with absorptivity of 94.1% at the peak absorption frequency of 120.8 GHz. We systematically investigate the surface current distribution and the power loss analysis, and explain the architecture of the absorber. Moreover, the absorber exhibits unique absorption properties at resonant frequencies, that is, featuring single‐band or dual‐band operation by changing the surface resistance of the ITO patterns. In addition, the experimental demonstration and measurement results are in good agreement with the simulated results. Most importantly, the fabricated absorber exhibits an optical transparency above 70% over the entire visible waveband, thereby enabling a wide range of applications such as optically transparent THz absorbers and detectors. 相似文献
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In this article, a broadband optically transparent metamaterial absorber in wireless communication band is proposed. Indium tin oxide (ITO) film, a kind of resistive transparent thin film, is utilized to construct the absorber unit to realize optical transparency, and increase ohmic loss to broaden the absorption bandwidth. The proposed absorber is fabricated and measured. The measurement results are in good agreement with the simulations. It is demonstrated that the absorption rate of the proposed absorber is higher than 90% from 1.67 to 3.8 GHz. The full width at half maximum bandwidth is 5.11 GHz from 0.89 to 6 GHz. In addition, the absorption response of the absorber remains stable regardless of polarization and incidence angle of the electromagnetic waves. 相似文献
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Emrullah Karakaya Fulya Bagci Sultan Can Asim Egemen Yilmaz Baris Akaoglu 《国际射频与微波计算机辅助工程杂志》2019,29(1)
A four‐band metamaterial harvester for harvesting 0.9 GHz, 1.8 GHz, 2.6 GHz, and 5.8 GHz signals is proposed by a dual‐layer structure. 0.9 GHz and 1.8 GHz bands are harvested by the resistors in front layer, whereas harvesting of 2.6 GHz is achieved by the resistors in second layer. All resistors in front and back layer contribute to harvesting at 5.8 GHz. Numerical calculations are verified by two different full‐wave electromagnetic solvers based on finite‐integration and finite‐element techniques. Power dissipation ratios at 0.9 GHz, 1.8 GHz, 2.6 GHz and 5.8 GHz frequencies concentrated at the resistors are found as 82.3%, 82.8%, 74.6%, and 83.6%, respectively, by the finite‐integration‐based solver. Besides, the finite‐element method‐based solver results in harvesting efficiencies of 79.6%, 93.4%, 73.7%, and 93.8%. The efficiency of the harvester is investigated for different oblique incidences. The proposed metamaterial harvester can be a good candidate for multi‐band absorption and harvesting applications. 相似文献
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针对能量收集分布式检测系统由于环境能量到达随机造成系统检测性能不稳定的问题,在同时考虑节点能量不确定性、探测能量不确定性、通信能量不确定的前提下,给出了一种基于节点能量使用门限的能量管理策略的确定方法。该方法首先优化探测和通信的能量分配方式,然后根据能量到达强度,对有限能量区间进行穷举搜索,确定合理的节点能量使用门限。该方法的优势是确定的策略是一种离线策略,不占用节点通信资源,电池存储能量是唯一执行条件,简单易行。仿真表明该方法确定的节点能量管理策略与“能量到达即使用”的策略相比,有效降低了能量随机到达对系统检测性能的影响,提升了检测系统平均检测性能。 相似文献
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电力铁塔倾斜检测是保障高压输电线路系统的安全和稳定运行的重要手段,目前状态检测设备都存在功耗高,依赖使用化学电池供电等问题。本文提出了一种集成自供能铁塔倾角无线传感系统,设计电磁能量采集器收集高空铁塔风能,通过低功耗能源管理电路进行能源存储与负载供电。用电磁仿真和实验验证了系统的性能,测试结果显示,采集器可以在2m/s的风速下启动,在8m/s的风速下,装置空载情况的RMS电压为1.25V,输出功率为8.2mW。用BQ25570芯片搭建低功耗能源管理电路,通过升压后输出3.3V对倾角传感器进行了供能测试。根据实验结果,此装置可以为铁塔倾角传感器或其他小型电气设备供电,这将为自供能物联网无线传感网络节点提供技术支持。 相似文献
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能量收集网络能够延长能量受限型网络的生命周期,然而目前的研究大多针对单一天线的网络系统,同时线性的能量收集模型无法准确刻画系统能量收集过程.为此,针对能量收集多用户多输入多输出认知无线供电通讯网络系统,基于非线性能量收集模型分别建立overlay和underlay场景下的系统吞吐量优化模型;由于系统模型的参数耦合和非线性约束特性导致问题为联合凹的,利用等效代换将系统模型转化为等效凸问题,使用拉格朗日对偶方法求解;继而分别给出能量与信息协方差矩阵最优解形式及最优时间分配系数的求解方法,并使用数学方法证明其最优性.最后,基于实际的风电能量收集数据,验证算法的有效性及性能.仿真结果表明,与平均功率分配算法相比,最优求解算法能够实现更好的平均系统吞吐量,同时所述算法均在有限次迭代后达到稳定收敛. 相似文献
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This article proposes a novel hybrid energy harvesting antenna that can be used to harvest radio frequency (RF) and vibration energy in ambience. A microstrip antenna is designed on the piezoelectric film with the material of polyvinylidene fluoride (PVDF). Due to the high dielectric constant of PVDF, the antenna size can be reduced efficiently. The shape of designed microstrip antenna is trapezoidal, the final antenna size is reduced to 50 mm × 30 mm × 0.2 mm. To improve the efficiency, the rectifier with matching network is optimized and the modes of the piezoelectric film are analyzed. The experimental results show that the frequency bandwidth of the antenna is 2.1 to 2.5 GHz. For a RF source at distance of 1 m away, with a 0.25 W EIRP 2.4 GHz transmitter, the output power of the antenna can reach 17.2 μW. While under 17 Hz vibration excitation, the output voltage and power can reach 1.44 V and 15.3 μW, respectively. 相似文献
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射频能量捕获是应对无线网络节点能量受限的有效方法之一.射频能量源（energy source,简称ES）的布置位置和发送功率决定了各个节点的能量捕获功率.现有的研究工作大部分考虑的是没有给定侯选位置的场景.然而,在实际应用场景中,网络区域往往存在很多不可布置能量源的区域,使得能量源只能在一些合理的候选位置中布置.目前仅有少量相关工作研究如何在ES的候选布置位置中选择合适布置位置.已知节点位置、节点的能量捕获功率需求值、ES的个数以及ES的候选布置位置.研究并设计了最小化ES总供能的ES布置与发送功率设置方案.首先将该问题建模为混合整数规划问题;然后分别提出了一种具有较低复杂度的启发式算法和一种能够达到更小总供能的基于遗传算法的算法.仿真结果表明,与布置位置随机挑选法相比,这两种算法的网络总功耗降低了约90%,而遗传算法可达到比启发式算法高约35%的节能效果.因此,基于遗传算法的布置算法可用于中小规模的ES布置场景,而启发式算法可用于大规模的ES布置场景. 相似文献
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Wireless sensor networks (WSNs) offer an attractive solution to many environmental, security, and process monitoring problems. However, one barrier to their fuller adoption is the need to supply electrical power over extended periods of time without the need for dedicated wiring. Energy harvesting provides a potential solution to this problem in many applications. This paper reviews the characteristics and energy requirements of typical sensor network nodes, assesses a range of potential ambient energy sources, and outlines the characteristics of a wide range of energy conversion devices. It then proposes a method to compare these diverse sources and conversion mechanisms in terms of their normalised power density. 相似文献
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无线传感器节点往往由电池供电,由于电池只能存储有限的能量,使得无线传感器网络注定寿命很短,因此,最大限度延长传感器设备的使用寿命是一个重要的研究方向和课题.在本次无线传感器网络节能探索研究中,分析了能量收集与管理策略,能量收集主要收集环境能源,如太阳能,通过超级电容实现能量的存储.能量管理主要通过能量预算让传感器节点处... 相似文献