Controllable Band‐Notched Slot Antenna for UWB Communication Systems

We propose a slot antenna consisting of a rectangular slot on the ground plane, fed by a microstrip line with a rectangular‐ring‐shaped tuning stub that can be deployed in ultra‐wideband (UWB) communication systems to avoid interference with wireless local area network (WLAN) communication. Our antenna can achieve a single band‐notched property from the 5 GHz frequency to the 6 GHz frequency owing to a controllable band notch that uses L‐ and J‐shaped parasitic elements. The antenna characteristics can be modified to tune the band‐notched property (4 GHz to 5 GHz or 6 GHz to 7 GHz) and the bandwidth of the band notch (1 GHz to 2 GHz). Furthermore, the shifted notch with enhanced width of the band notch from 1 GHz to 1.5 GHz is described in this paper. The UWB slot antenna and L‐ and J‐shaped parasitic elements also provide the band‐rejection function for reference in the WiMAX (3.5 GHz) and WLAN (5 GHz to 6 GHz) regions of the spectrum. Experiment results evidence the return loss performance, radiation patterns, and antenna gains at different operational frequencies.     

Design of a Guitar Shaped UWB Antenna with Wide Band Notched Characteristics for Wireless Applications

Cloud storage is a cloud based service which delivers scalable on demand on line storage of data and eliminates the need of maintaining local data centre. Storage of data in cloud brings many advantages such as lower-cost, metered service, scalable and ubiquitous access. However, it also raises concerns to its integrity; to save the storage space cloud service provider may delete some rarely access data. Data privacy is another issue which must be addressed to increase data owner’s trust. To address above issues, many researchers have proposed public auditing schemes to validate the integrity of data using third party auditor. These schemes generate metadata using data files on the owner side and store these metadata on the cloud storage along with the file data, which helps in auditing. These schemes address many concerns which arise due to remote data storage. However, computation cost involved for metadata generation at the data owner side is not properly addressed; another issue which is not properly addressed is an iniquitous third party auditor may be the source of denial of service attack by issuing constantly large number of audit request. Our scheme solves these issues by lowering the computation cost at data owner side and controlling the number of times a third party auditor can issue an audit request to the cloud storage. Our Scheme also supports secure access of data using conditional proxy re-encryption scheme and delegation of auditing task by the authorized third party auditor to another auditor for the specified period of times in the case of unavailability of authorized third party auditor.

     

超宽带Koch分形缝隙天线的陷波特性研究

提出了超宽带Koch分形缝隙天线的设计方法。通过引入Koch分形,可显著缩小超宽带缝隙天线的体积,同时还可以通过调整分形缝隙的边界花样长度获得灵活的陷波功能。给出了Koch分形天线的设计过程,通过理论计算和尺度放大实验,研究了天线的陷波性能。实验与理论计算的良好吻合表明文中提出的方法是正确有效的。     

Symmetrical Hexagonal Monopole Antenna with Bandwidth Enhancement Under UWB Operations

Wireless Personal Communications - This paper presents the design and development of a livestock tracking system, with the objective of transmitting the location and activity status of the animals,...     

微带宽缝天线的谐振频率和带宽特性

借助时域有限差分法(FDTD)对微带宽缝天线的频率和带宽特性进行了分析讨论.采用高斯脉冲激励,对计算空间采用非均匀网格划分,通过FDTD,一次计算就可得到天线谐振频率和带宽的参数.研究了微带宽缝天线的频率和带宽特性随着缝宽变化的规律.发现当缝宽从1mm增加到30mm时,天线的谐振频率从3.4GHz降低到2.3GHz,天线的10dB带宽可从9%增加到28%.     

一种具有三陷波特性的超宽带印刷天线设计

提出了一种新型的具有三陷波特性的超宽带印刷天线。大钱形的辐射贴片和共面波导传输线馈电,可以保证在相当宽的3个频带内具有良好的阻抗匹配。回波损耗S₁₁＜-10 dB的阻抗带宽是3.1~10.6 GHz,除了其中3.3~3.7 GHz 的WiMAX,5.15~5.825 GHz的WLAN和7.25~8.4 GHz的X波段下行频段3个陷波频段。这些陷波的频段可以通过在天线的辐射贴片上增加长条裂缝和U形缝隙实现。加工和测试结果表明,该天线具有很好的阻抗带宽和全向辐射方向图。     

A Circular Slot Antenna with Wide Tunable and Reconfigurable Frequency Rejection Characteristic Using Capacitance Loaded Split-Ring Resonator for UWB Applications

A coplanar waveguide-fed circular slot antenna with wide tunable and reconfigurable frequency rejection characteristic is proposed numerically and verified experimentally. The frequency rejection function is realized by using a capacitance loaded split-ring resonator (CL-SRR). The wide tunable frequency rejection characteristic is implemented by adjusting the dimensions of the CL-SRR and the reconfigurable frequency rejection characteristic is realized by integrating two switches into the CL-SRR. The antenna has a small size of \(32\,\hbox {mm}\times 24\,\hbox {mm}\) including the ground plane. Simulation and measurement results show that the proposed antenna with omnidirectional radiation patterns and reconfigurable notch bands is suitable for ultra-wideband and cognitive radio communication applications.     

Twisted F-Shaped Slot Loaded UWB Printed Antenna for On-Body Application

Wireless Personal Communications - Compact UWB antenna manufactured in twisted F form with slots loaded is exhibited. An ultra-wideband 3.1 GHz to 10.6 GHz with modified ground...     

低雷达截面的超宽带Koch分形槽缝天线

设计了一种具有低雷达截面的超宽带分形槽缝天线。利用"突出角"为90°的Koch分形对方形槽天线进行3次迭代设计后,-10dB阻抗带宽范围由方形槽缝天线的3.0～13.1GHz变为2.8～13.7GHz。仿真和测试结果显示,天线在3GHz和8GHz方向图对称,在整个频段内相对于原天线的增益更稳定,且具有较低的雷达散射截面(RCS)。该天线适用于对超宽带天线具有低RCS要求的场合。     

一种小型陷波多用途超宽带天线

提出了一种小型陷波多用途超宽带微带天线。该天线与一般的宽缝隙微带天线类似,通过在矩形调谐支节上开V形缝隙获得了陷波特性。通过数值仿真和实验测量,对天线的阻抗特性、方向图和增益进行了研究。结果显示该天线在2.4到11GHz频段内驻波比小于2,在5.15~5.95 GHz范围内具有陷波特性。同时该天线还可覆盖2.4GHz无线局域网(WLAN)频段,在整个工作频段内有良好的辐射方向特性。     

Frequency Notched UWB Planar Monopole Antenna Optimization Using a Finite Element Method-Based Approach

The objective of this work is the design and optimization of an ultrawideband (UWB) planar monopole antenna with frequency-notched behavior intended to get rid of the 5–6 GHz frequency band for WLAN compatibility purposes. An optimized profile UWB planar monopole designed by means of a Simulated Annealing algorithm and full three-dimensional finite element method, detailed in a companion paper, was considered as the design starting point. In order to design the band-notched rejection no full finite element analysis is carried out on each profile modification as is usual. The procedure is based on a genetic algorithm and a multipurpose admittance matrix approach instead. Artificial ports are allowed in the computational domain and an admittance-type matrix comes up. As a result, a multiport network describes the electromagnetics within the analysis domain. Circuit manipulations of this network efficiently outperform full-wave analyses for different monopole modifications, thus making it possible to use this strategy in a computer aided-design scheme.      

准八木型宽带微带天线单元的设计

利用三维电磁场仿真软件(Ansoft HFSS)对准八木型微带天线单元进行了仿真计算.研究了天线结构参数对天线性能的影响.最后得到一个良好的设计。实验结果与计算值相吻合。     

具有陷波功能的超宽带缝隙天线的设计与研究

提出了一种具有陷波功能与分形调谐支节的新型超宽带缝隙天线.该天线的结构类似于一般的微带缝隙天线,通过采用分形调谐支节引入半波长谐振结构,使得该天线不仅具备了超宽带缝隙天线的优点,还具备灵活可调的陷波功能.通过计算、测量和尺度放大实验,充分考察了天线的频域特性.实验结果表明该天线的工作频带为2.66～10.76 GHz,在4.95～5.85 GHz频段上具有陷波功能,同时具有相对稳定的辐射方向性和近似的全向特性.该研究对设计小型超宽带天线具有一定的价值.     

Ultra-Wideband Slot Antenna with Rejection of WLAN and ITU Bands Using Protruded Strip Resonators

In this paper, a different method for designing a new slot antenna with dual band-notched characteristic for ultra-wideband applications is presented. The proposed antenna consists of a square-ring radiating stub with an inverted T-shaped strip protruded inside the ring, a feed-line with an E-shaped strip protruded inside the rectangular slot, and a ground plane with a pair of L-shaped strips protruded inside the extra rectangular slot. In this study, by using a a pair of L-shaped strips protruded inside the slot in the ground plane, additional resonance is excited and hence much wider impedance bandwidth can be produced. By using this modified structure in the ground plane, the antenna provides a wide usable fractional bandwidth of more than 130 % (3.01–15.35 GHz). To generate a single band-notched function, we convert a square radiating patch to a square-ring with an inverted T-shaped strip. Finally, by adding a rectangular slot with a protruded E-shaped strip in the microstrip feed line, a dual band-notched function is achieved. The measured results reveal that the presented dual band-notched slot antenna offers a very wide bandwidth with two notched bands, covering all the 5–6 GHz wireless local area network, 8–8.5 GHz international telecommunication union bands.     

一种新颖的Koch分形缝隙天线研究

设计了一种新颖的多频带天线。给出了传统矩形波导的归一化宽度公式,并介绍了Koch曲线的基本概念,利用电磁仿真软件HFSS对天线的电特性进行仿真优化。Koch分形结构具有自相似性,故天线具有良好的多频带特性,通过讨论,设计出了3个谐振频率,分别为3.9 GHz,4.5 GHz和13.4 GHz,而且该天线面积小,约为78.7 mm×40 mm。     

Performance of a Crossed Exponentially Tapered Slot Antenna for UWB Systems

A compact printed antenna is described that exhibits adequate transient performance for ultrawideband (UWB) applications and it is further adequate for polarization diversity schemes. The antenna is based on an original combination of two crossed exponentially tapered slots plus a star-shaped slot to produce a stable radiation pattern with very stable polarization over the 3.1–10.6 GHz FCC assigned band. Results are confirmed with measurements. Figures of merit like output pulse fidelity and time window containing 90% of the transmitted energy are analyzed over the entire solid angle and showed to remain quite stable, in line with envisaged UWB system requirements. Compact dual-antenna arrangements are also analyzed in view of potential use for UWB multiple-input–multiple-output implementations.      

新型小尺寸三陷波超宽带天线的设计

设计了一种紧凑的具有三陷波特性的超宽带天线。天线采用渐变微带线馈电,并通过矩形加半圆的辐射单元和半圆形地板来实现超宽带。通过在辐射单元上刻蚀对称的L形槽和圆环形槽,来实现在WLAN/WiMAX的陷波特性;在渐变微带馈线两侧增加对称的C形谐振器来达到在X频段的陷波特性。实验结果表明,天线在2.68~13GHz频段内电压驻波比小于2,同时在3.1~3.8GHz,5~5.9GHz,7.25~7.85GHz频段内有陷波抑制作用,且具有良好的辐射特性。天线具有较小的几何尺寸,仅为20mm×30mm。     

Dual Band-Notched Small Monopole Antenna with Enhanced Bandwidth for UWB Applications

This article proposes a novel printed monopole antenna for ultra wideband applications with dual band-notch function. The antenna consists of a disc-shaped radiating patch with a pair of folded strips arms, and a ground plane with a two L-shaped conductor backed plane, which provides a wide usable fractional bandwidth of more than 140 % (2.6–14.43 GHz). In order to generate single band-notch characteristics, we use a modified disc-shaped radiating patch with a pair of folded strips arms also by using this modified radiating patch, additional resonance is excited and hence much wider impedance bandwidth can be produced, especially at the higher band. By adding two L-shaped conductor backed plane in the ground plane a dual band notch function is achieved. The measured results reveal that the presented dual band-notch monopole antenna offers a very wide bandwidth with two notched bands, covering all the 5.2/5.8 GHz WLAN, 3.5/5.5 GHz WiMAX and 4 GHz C bands. The designed antenna has a small size of $12\times 18\,\hbox {mm}^{2}$ .     

Reconfigurable Wide Bandwidth Using Novel Extraction Technique of Slotted Monopole Antenna with RF CNT Network

Wireless Personal Communications - This work first moment focuses on the concept of reconfigurable wide bandwidth using novel extraction technique of slotted monopole antenna with RF carbon...     

一种共面波导馈电的三阻带超宽带天线设计与研究

设计了一种共面波导馈电的超宽带天线(UWB),该天线的辐射体和地板分别由具有渐变结构的类圆辐射贴片和梯形组成,具有良好的宽带阻抗匹配特性。通过在贴片的不同位置上嵌入3种不同形状的缝隙,实现了天线的3陷波特性。并利用HFSS 12软件对所设计的天线进行仿真测试,仿真计算和实测结果表明,该天线在WiMax(3.3～3.7G)、Wlan(5.15～5.825GHz)以及ITU(8.025～8.4GHz)3个频段内具有良好的陷波特性,并且该天线在其它通带频段具有良好的辐射特性和稳定的增益。天线的尺寸仅有25mm×29mm×1mm,利于与微波器件的集成。