Crosspolar performance of annular-ring microstrip antenna with novel mode suppression

The crosspolarisation of annular-ring microstrip patches resonating in the TM/sub 12/ mode is discussed. It is shown that circumferential slots within the rings can suppress other modes and improve the radiated crosspolarisation levels.<>     

Electromagnetic radiation from structures consisting of combinedbody of revolution and arbitrary surfaces

A formulation is developed to treat radiation from structures consisting of a body of revolution (BOR) in the presence of multiple arbitrarily shaped three-dimensional objects. An electric field integral equation is set up on the surface of the combined structure. The resulting integro-differential equation is solved using the method of moments. On the BOR, harmonic entire domain expansion functions are used for the circumferential dependence, while overlapping subdomain functions are used to model the axial curvature. The arbitrarily shaped portions of the structure are modeled using triangular surface patches. The resulting system matrix has a partial block diagonal nature, which provides a more economical solution for structures that have some rational symmetry. Numerical results are presented and compared to measurements of a unique cavity-backed patch fed antenna     

Reconfigurable patch antennas for steerable reflectarray applications

Reconfigurable reflectarrays have been designed with patch elements which can vary the reflected phase by varying the height of the patches. These patches have been designed using a periodic method of moments simulation. Reflectarrays incorporating elements of varying heights have been built and tested. The first design is a 33 element array comprised of stacked patches which operates at 7.31 GHz. The second design is a 120-element dipole array over a ground plane which operates at 5.2 GHz. Microelectrical, mechanical systems actuation technology could be used to implement these designs and a potential concept is suggested.     

Making planar antennas out of solar cells

A presentation is made of the possibility of replacing metallic patches by solar cells in planar antennas. To demonstrate the concept, a slot-fed microstrip antenna using solar cells instead of a copper patch has been realised and measured. The results show that the 'solar cell patches' have characteristics equivalent to copper patches     

Near fields of microstrip antennas

The paper presents an iterative method for the computation of the near fields of single layer microstrip patch antennas. A judicious combination of the advantages of the MPIE (mixed potential integral equation) method, the FFT algorithm and the biconjugate gradient leads to an efficient numerical solution. The scheme can deal with patches of arbitrary shapes and is capable of dealing with a very large number of unknowns. Near field computation is done in a straightforward manner by computing the weighted near fields. For illustration, three patches belonging to the family of generalized annular sector have been chosen. Computed results of input impedances with a coaxial probe excitation have been compared with measurements. Computed near field amplitudes have also been compared with measured results where possible. Computed far field characteristics have been correlated with the near field information     

PKG‐VUL: Security Vulnerability Evaluation and Patch Framework for Package‐Based Systems

In information security and network management, attacks based on vulnerabilities have grown in importance. Malicious attackers break into hosts using a variety of techniques. The most common method is to exploit known vulnerabilities. Although patches have long been available for vulnerabilities, system administrators have generally been reluctant to patch their hosts immediately because they perceive the patches to be annoying and complex. To solve these problems, we propose a security vulnerability evaluation and patch framework called PKG‐VUL, which evaluates the software installed on hosts to decide whether the hosts are vulnerable and then applies patches to vulnerable hosts. All these operations are accomplished by the widely used simple network management protocol (SNMP). Therefore, system administrators can easily manage their vulnerable hosts through PKG‐VUL included in the SNMP‐based network management systems as a module. The evaluation results demonstrate the applicability of PKG‐VUL and its performance in terms of devised criteria.     

Scattering from a periodic array of free-standing arbitrarily shaped perfectly conducting or resistive patches

A fast Fourier transform (FFT)-based iterative approach for computing the fields scattered by an infinite array of free-standing patches is presented. The method is capable of handling patches that are lossy and have arbitrary shape; it is useful for analyzing configurations that may not have been analyzed previously. Though a rectangular FFT is used, the formulation allows the study of the common triangular array periodicities. Results for various geometries are presented and are compared with existing results.     

Smart Skin-Adhesive Patches: From Design to Biomedical Applications

With the advancement of medical and digital technologies, smart skin adhesive patches have emerged as a key player for complex medical purposes. In particular, skin adhesive patches with integrated electronics have created an excellent platform for monitoring health conditions and intelligent medication. However, the efficient design of the adhesive patches is still challenging as it requires a strong combination of network structure, adhesion, physical properties, and biocompatibility. To design an assimilated device, one must have a deep knowledge of various skin adhesive patches. This article provides a comprehensive review of the recent advances in skin-adhesive patches, including hydrogel-based adhesive patches, transdermal patches, and electronic skin (E-skin) patches, for various biomedical applications such as wound healing, drug delivery, biosensing, and health monitoring. Furthermore, the key challenges, implementable strategies, and future designs that can potentially provide researchers in designing innovative multipurpose smart skin patches are discussed. These advanced approaches are promising for managing the health and fitness of patients who require regular medical care.     

Polarisation agile active microstrip patch arrays

Two three-element polarisation-agile active microstrip patch arrays have been developed. The radiating elements are square patches each with two transistors mounted on adjacent edges. The patches radiate orthogonal modes, the relative phase of which can be varied. Radiation patterns show good agreement with predictions from theory, in both linear and circular polarisation, and no grating lobes were observed     

Gray-level image denoising with an improved weighted sparse coding

The nonlocal self-similarity of images means that groups of similar patches have low-dimensional property. The property has been previously used for image denoising, with particularly notable success via sparse coding. However, only a few studies have focused on the varying statistics of noise in different similar patches during the iterative denoising process. This has motivated us to introduce an improved weighted sparse coding for gray-level image denoising in this paper. On the basis of traditional sparse coding, we introduce a weight matrix to account for the noise variation characteristics of different similar patches, while introduce another weight matrix to make full use of the sparsity priors of natural images. The Maximum A-Posterior estimation (MAP) is used to obtain the closed-form solution of the proposed method. Experimental results demonstrate the competitiveness of the proposed method compared with that of state-of-the-art methods in both the objective and perceptual quality.     

Research on planar antennas and arrays: `structures Rayonnantes'

The basic research on radiowave systems dealing with electromagnetism, electronics, and signal processing at the University of Rennes is discussed. The fusion of these different domains occurs for studies concerning systems where radiating structures, active devices and interfaces, and signal processing play a fundamental role and cannot be separated. Different geometries and methods developed for various types of patches, dipoles, and slot antennas, including patch antennas with coaxial or microstrip feeds, printed slot antennas, slot-fed patches, slot-loaded patches, and electromagnetic coupled dipoles and patches, are described. Different kinds of arrays have been designed with active or passive feed networks. The analysis includes mutual-coupling effects, especially when beam steering is considered with small element spacing. Arrays considered include planar phased arrays, planar passive arrays, dual-beam printed antennas, and arrays of microstrip dipoles     

Combining the moment method with geometrical modelling by NURBSsurfaces and Bezier patches

Induced current distributions on conducting bodies of arbitrary shape modelled by NURBS (non uniform rational B-splines) surfaces are obtained by using a moment method approach to solve an electric field integral equation (EFIE). The NURBS surfaces are expanded in terms of Bezier patches by applying the Cox-de Boor transformation algorithm. This transformation is justified because Bezier patches are numerically more stable than NURBS surfaces. New basis functions have been developed which extend over pairs of Bezier patches. These basis functions can be considered as a generalization of “rooftop” functions. The method is applied to obtain RCS values of several objects modelled with NURBS surfaces. Good agreement with results from other methods is observed. The method is efficient and versatile because it uses geometrical modelling tools that are quite powerful     

基于多特征扩展pLSA模型的场景图像分类

场景图像分类近年来受到人们的广泛关注,而基于统计模型的方法更是场景分类中的研究热点。我们提出了一种新的基于多特征融合和扩展pLSA模型的场景图像分类框架。对每幅图像首先用多尺度规则分割确定局部基元,然后提取每个局部基元的多分辨率直方图矩特征和SIFT特征,最后用扩展的概率生成模型对图像集进行建模,测试。我们的方法不仅能够很好的表示图像的语义特性而且在模型的训练阶段是无监督的。我们针对目前常用的3个数据库,做了三组对比实验,均取得了比以前的方法更好的识别结果。      

Effect of surface distortions on the crosspolarisation performance of paraboloidal reflectors

The effects on the crosspolarisation and the radiation patterns of circular paraboloidal reflectors produced by (a) reflector distortions which are periodic in the circumferential direction and (b) a lateral offset of the feed have been evaluated for a wide range of reflector and feed parameters. It is shown that the use of a balanced hybrid-mode feed minimises crosspolarisation introduced by reflector distortions.     

基于复自然谐振的无芯RFID标签的设计

本文提出了一种基于复自然谐振的无芯RFID标签的设计。标签由两个梯形金属贴片组成,两组谐振频率邻近的缝隙谐振器分别加载在两个贴片上。在不增加缝隙间相互耦合的前提下,标签在UWB频段内容纳的数据位数提高了一倍,在35mm×33mm的合理尺寸内,12个缝隙谐振器对应12位数据。仿真给出了标签的RCS曲线和极点分布图,实测是在双站天线配置下进行,在频域内测出了传输系数和极点分布图。实测和仿真结果一致,验证了本设计的合理性。该标签具有低剖面、低成本和高数据率的优点,因其只需要一个导电层,所以能被直接印刷在ID卡甚至纸张上面。     

Analysis of a low profile slotted microstrip antenna for cellularmobile radio

The TM₀₁ mode of a circular resonant microstrip cavity has been used to produce an omnidirectional vertically polarized antenna with a broadside null. Interlaced circumferential slots were added, resulting in reductions in the resonant frequency of up to 50%. The performance of this antenna when mounted on the roof of an automobile has been analyzed through the application of the geometric theory of diffraction (GTD). Chebychev matching networks have been investigated to implement a broadband impedance match to the antenna     

Hybrid-coupled shorted rectangular microstrip antennas

Hybrid-coupled (both gap and direct) shorted rectangular microstrip antennas have been investigated. Only one patch is fed and the other patch is parasitically coupled along the radiating and the non-radiating edges, respectively. Dual frequency and broadband operation has been obtained by optimising the coupling between the two patches through a copper strip     

Scattering and Pattern Perturbation by a Conducting Tubular Cylinder of Finite Length

This paper uses the plane-wave-spectrum (PWS) scattering technique to determine the scattering and pattern-perturbation effects of a conducting tubular cylinder of a finite length situated in the neighborhood of a 2 x 4 dipole array. Both the axial and the circumferential current distributions induced on the cylinder due to a unit-magnitude incident plane wave have been calculated. Typical patterns for the scattered field and the perturbed radiation field are presented for various cylinder locations.     

Twisted nematic liquid-crystal electro-optic devices with areas of reverse twist

Liquid-crystal displays based on an induced twist in a nematic liquid often have a patched appearance when viewed at nonnormal incidence. This fault has previously been unexplained. It is shown by experiment that the patches reveal regions of reverse twist relative to that in neighbouring areas.     

Multipurpose Intraperitoneal Adhesive Patches

The intraperitoneal (IP) cavity is the largest fluid‐filled space in the body and contains important organs. Although peritoneal fluid from the abdominal cavity lubricates and allows organ motion, this fluid also effectively prevents polymeric material implantation. Anastomotic leakage after surgery has been reported but few sealing methods have been developed. Herein, a fluid‐resistant adhesive called IP patch is reported that seals intestinal neo‐anastomosis sites, preventing anastomotic leakage after colorectal surgery. The bursting pressure, which is the most important index of the degree of healing after colorectal anastomosis surgery, is measured from an IP patch applied to rats (188.3 ± 14.5 mmHg) and is highly similar to the pressure observed from normal tissue (210.2 ± 22.9 mmHg). Additionally, IP patches can act as unprecedented local drug reservoirs due to the aforementioned tissue adhesive property. Drug‐loaded IP patches successfully treated multiple‐site occurrence of small peritoneal cancerous colonies. The anticancer drug‐loaded IP patches are applied to potential risk regions for recurrent and metastasized cancer in the IP cavity after the resection of peritoneal solid tumors. Thus, the multifunctionality of IP patches can be usefully exploited as an adhesive biomaterial that works effectively in difficult‐to‐treat diseases observed in IP environments.