2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications最新文献

{"title":"Overview of 6 Years R&D on Characterizing Wireless Devices in Rayleigh Fading Using Reverberation Chambers","authors":"P. Kildal","doi":"10.1109/IWAT.2007.370102","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370102","url":null,"abstract":"The paper gives an overview of how measurements in reverberation chambers can be used to characterize the performance of small antennas and wireless terminals for mobile communications in environments with Rayleigh fading. The measurement capabilities include radiation efficiency, radiated power, diversity gain, MIMO system capacity and receiver sensitivity. In the latter case the reverberation chamber enable fast measurements of bit error rate (BER) and frame error rate (FER), and thereby total isotropic sensitivity (TIS). In addition, the terminals can be tested under realistic and continuous fading very similar to what is present in urban and indoor environments, referred to as average fading sensitivity (AFS). The chamber is the only known measurement instrument for directly measuring diversity gain and channel capacity; the alternative being to drive measurement instruments around in an actual urban environment. The measurements can fast and easily be performed for different talk positions relative to a head phantom.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"36 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128054529","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Low Profile Tilted Beam Single Arm Spiral Antenna On A High Impedance Surface For Beam Steering Applications","authors":"A. Mehta, A. Sanada, D. Mirshekar-Syhakal, H. Nakano","doi":"10.1109/IWAT.2007.370161","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370161","url":null,"abstract":"This paper presents the extension of the high impedance surface (HIS) idea and its application to the switchable beam single arm spiral antennas proposed in (A. Mehta et al., 2006, 2004) in order to reduce its substrate thickness. A low profile single arm spiral antenna for tilted beam radiation using a small ground plane (0.97 lambdag) and a practical coax feeding from bottom is presented. As pointed out in (A. Mehta et al., 2006) the spiral antenna generates a tilted beam when the radiation occurs from its first two wavelength loop concurrently. Using switches, as shown in (A. Mehta et al., 2006), the radiation from the second wavelength loop can be altered resulting in steering of the beam in the space. Hence, steering a tilted beam in space is easy with the structure proposed, consequently it helps in achieving an uncomplicated beam swing. Since it is low profile, this antenna is suitable for implementation in small wireless transceivers for beam adaptive applications.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"312 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122699389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"BER Performance of W-CDMA Reciever Using Adaptive Array Antenna Technique in Indoor LOS/NLOS Environments","authors":"Q. Yuan, Y. Takeda, K. Oya, Q. Chen, K. Sawaya, E. Kudoh, F. Adachi","doi":"10.1109/IWAT.2007.370115","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370115","url":null,"abstract":"The wide band code division multiple access (W-CDMA) receiver combined with adaptive array antenna (AAA) technique is developed and used to measure the bit error rate (BER) performances in indoor line of sight (LOS) and non line of sight (NLOS) environments. Since the BER changes with the orientation of the receiving antenna in indoor environment, the mean BER is proposed by averaging all BERs at each orientation of receiving antenna along the azimuth direction. Compared with the single antenna when BER is equal to 10-2, the experimental results have demonstrated that signal-to-interference ratio (SIR) can be improved by 10 dB in indoor LOS environment and 8 dB in indoor NLOS environment, respectively.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122157277","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Miniaturization of Planar Monopole Antennas for Ultrawide-Band Applications","authors":"Mei Sun, Yue Ping Zhang","doi":"10.1109/IWAT.2007.370110","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370110","url":null,"abstract":"A significant 40% reduction in size has been realized for LTCC based beveled planar monopole antenna for UWB applications by simply exploiting its structural symmetry. The miniaturized antennas exhibit wider impedance bandwidth, higher cross-polar radiation, and slightly lower gain at higher frequencies as compared with their unminiaturized counterparts. These effects of miniaturization are confirmed with measurements of both unminiaturized and miniaturized beveled monopole antenna. The final miniaturized beveled monopole antenna of size 17times10times1 mm3 achieved impedance bandwidth of 8.25 GHz from 2.85 to 11.1 GHz, gain from -5.6 to 2.3 dBi, and broad patterns. In addition, both frequency domain and time domain characteristics of the beveled monopole antennas were also carefully investigated with a normalized measured transfer function. They all proved the feasibility of the miniaturization and applicability of this miniaturized beveled monopole antenna in UWB radios.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"34 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125501042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Critical Look at the Performance Enhancement of Small Antennas using Metamaterials","authors":"R. Mittra","doi":"10.1109/IWAT.2007.370069","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370069","url":null,"abstract":"Currently, there is a great deal of interest in enhancing the performance of small antennas using metamaterials. Of course, the interest itself is not new, since the search has always been actively pursued for ways to increase the directivity, reduce the sidelobe and backlobe levels, improve the bandwidth, etc., of small antennas whose dimensions are limited by the available real estate. What is novel on the scene, then, is the advent of metamaterials, which have been touted as the magic bullet that would lead in to the holy grail of small antenna design, namely, a size that is small comparable to the wavelength, but one that has a high directivity (and even gain), wide impedance and pattern bandwidths, etc., but with little or no limitations that compromise the performance of the antenna. The purpose of this paper is twofold. First, we compile the various definitions of metamaterials that have appeared in the literature with a view to examining them critically and then coming up with one that not only appears to have a consensus, but also one that makes practical sense. We separate the metamaterials that are artificial dielectrics - typically periodic in nature into two principal categories: (i) those with unit cell sizes that are small comparable to the wavelength (aplambda/10) and display SNG or DNG characteristics; (ii) the periodic structures whose unit cell dimensions are on the order of lambda - typically in the range of lambda/2 - and which are also referred to as EBG materials and frequency selective screens (FSSs). Some examples are shown. The paper then presents examples of both antenna/metamaterial and antenna/EBG composites, used as substrates, superstrates as well as shell type of covers enclosing small antennas. Following this, the paper examines some theoretical limits on the directivity, gain-bandwidth product, etc., to see if the use of SNG or DNG metamaterials enables us to breach these limits. Finally, the paper also poses the question whether the use of DNG offers any advantage over the conventional use of EBG substrates and superstrates, and attempts to answer it via some examples","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124613366","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bandwidth Performance of Linearly Constrained Minimum Variance Beamformers","authors":"Lei Yu, Nan Lin, Wei Liu, R. Langley","doi":"10.1109/IWAT.2007.370141","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370141","url":null,"abstract":"The bandwidth performance of a linearly constrained minimum variance (LCMV) beamformer with and without tapped delay-lines (TDLs) processing is examined. A narrowband beamformer (without TDLs) is able to suppress wideband signals, but with the cost of a large number of sensors. As a solution to this problem, TDLs are introduced, which leads to the well-known wideband beamforming structure. It is shown how the SINR (signal to interference plus noise ratio) improves for different signal bandwidths with an increasing number of sensors for the narrowband structure, and by changing the length of the TDLs for the wideband structure","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125719202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impedance Bandwidth Enhancement For UWB Slot Antenna","authors":"D. Chang, Ji-Chyun Liu, Bing‐Hao Zeng, Ming-Yen Liu","doi":"10.1109/IWAT.2007.370107","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370107","url":null,"abstract":"A design for enhancing impedance bandwidth of wideband slot antenna is proposed and studied. The wideband slot antenna with a finite ground plane on the 50 ohm SMA connector is used for enhancing the impedance bandwidth. The measured results of the proposed antenna show that the impedance bandwidth is related with dimensions of a finite ground plane. By properly adjusting the dimension of finite ground plane, the antenna of UWB (ultra wideband) for IEEE802.15.3a can be achieved. For the 10 dB return loss, the bandwidth of the proposed antenna is from 2.3 GHz to 12 GHz. The gain variation is changing from 0.2 to 6.98 dBi. The test results agreed well with those of simulation.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"367 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134326608","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Accurate and Simple Design of High Impedance Surface Structure Using an Enhanced Effective Medium Method","authors":"G. Niyomjan, Y. Huang","doi":"10.1109/IWAT.2007.370152","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370152","url":null,"abstract":"The effective medium method is by far the most commonly used method in designing mushroom-like high impedance surface (HIS) structures. This is mainly due to its simplicity and flexibility, however it has some drawbacks such as its accuracy. If it is used directly to design a HIS structure without applying proper rules and limits, this can cause an inaccuracy to the design. As a result, further tuning and modifying will be required. These processes are usually done by using simulation tools based on numerical methods such as the finite element method (FEM) which might take enormous amount of time and computational resources. The aim of this paper is to investigate the possibilities of improving the conventional effective medium method to offer simplicity, speed and accuracy. This is done by setting a parametric study to obtain a required set of rules and limits that will be used prior to applying the method. A test structure has been designed and created to validate the method. A close agreement between the values of reflection phase angle (-90 to 90 degree) and surface impedance from 4 to 8 GHz is obtained by using this proposed improved method and numerical simulation.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132346999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of Antenna Designs Using the FDTD Simulation Method Enhanced with the Subcell Modeling Technique","authors":"S. Benkler, N. Chavannes, N. Kuster","doi":"10.1109/IWAT.2007.370177","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370177","url":null,"abstract":"This article demonstrates the capability of using the finite-differences time-domain (FDTD) method as simulation tool for optimizing the design of an antenna. The FDTD simulation method is locally enhanced with subcell modeling technique, which incorporates a-priori known field behavior in (1) curved material interfaces and (2) strong field gradients near sharp metal edges. Combining the FDTD subcell modeling technique with a FDTD simulation hardware acceleration card enables the efficient optimization of several parameters based on genetic algorithms.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129598801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Topology Optimization of Multiband Dielectric Resonator Antennas Using Finite-Difference Time-Domain Method","authors":"T. Nomura, K. Sato, S. Nishiwaki, M. Yoshimura","doi":"10.1109/IWAT.2007.370099","DOIUrl":"https://doi.org/10.1109/IWAT.2007.370099","url":null,"abstract":"In this research, we propose a new topology optimization method for the design of dielectric resonator antennas (DRAs) aiming to operate with enhanced bandwidths at multiple operational bands, using the finite difference-time domain (FDTD) method for electromagnetic analysis and the finite element method (FEM) for structural mechanics analysis. First, the concept of topology optimization is briefly discussed, and a way to integrate topology optimization with the FDTD method and the FEM is proposed. Next, a DRA design example is presented to confirm the usefulness of the proposed method.","PeriodicalId":446281,"journal":{"name":"2007 International workshop on Antenna Technology: Small and Smart Antennas Metamaterials and Applications","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133623606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}