A miniaturized metamaterial slot antenna for wireless applications

A novel miniaturized five band metamaterial inspired slot antenna is reported. The proposed design consists of a ring monopole and metamaterial Rectangular Complementary Split Ring Resonator (RCSRR) as the radiating part, two L and one T–shaped slot as the ground plane, respectively. Miniaturization in the proposed design is accomplished by metamaterial RCSRR, and also, it helps the antenna to operate at 2.9 and 5.2 GHz frequency bands. The aforementioned miniaturization process leads to about 46.8% reduction in volume of the proposed design, as compared to the conventional antenna. The pass band characteristics of the metamaterial RCSRR through waveguide medium are discussed in detail. In order to enhance the operating abilities of the miniaturized antenna, slots are etched out in the ground plane, thereby making the miniaturized antenna further operate at 2.4, 5.6 and 8.8 GHz, respectively. The proposed design has an active patch area of only , with dB bandwidth of about 4.16% (2.35–2.45 GHz), 5.71% (2.63–2.76 GHz), 10.25% (4.44–4.92 GHz), 6.25% (5.42–5.77 GHz) and 2.39% (8.68–8.89 GHz) in simulation, and about 6.86% (2.25–2.41 GHz), 5.01% (2.55–2.7 GHz), 9.16% (4.58–5.02 GHz), 5.38% (5.79–6.11 GHz) and 5.42% (8.44–8.91 GHz) in measurement. The antenna has good impedance matching, acceptable gain and stable radiation characteristics across the operational bandwidths.     

集总参数电磁人工超材料在无线能量传输中的应用

文章在磁共振式无线能量传输系统的基础上,应用磁单负特异材料,设计出一种能够实现磁场聚焦的特异材料平板透镜,并将其应用到谐振式无线能量传输系统之中提高传输效率。     

Charge pump design for high-voltage biasing applications in piezoelectric-based miniaturized robots

Fully autonomous piezoelectric-based miniaturized robots usually have a high-voltage biasing system that provides the required voltage levels to drive properly their piezoelectric actuators. In this paper a novel on-board biasing system based on the cascade connection of three full-custom charge pump ICs is presented. Simulated and experimental results show that the proposed biasing system is capable to obtain a regulated output voltage up to 20 V from a 3.3 V battery and deliver successfully up to 120 mW of power. Moreover, a novel approach in the steady-state analysis of the two-phase voltage doubler (which is the core of the designed charge pump IC) has been developed in order to have a tool capable to provide a full understanding of the steady-state voltage doubler’s behavior while at the same time accelerate and simplify the design process of such circuit. Simulated results show that the proposed mathematical model is more accurate than already developed models. The design of the charge pump IC has been implemented using a commercial 0.7 μm Bipolar-CMOS-DMOS (BCD) technology.     

Novel miniaturised wideband baluns for MIC and MMIC applications

Very compact novel planar broadband baluns are described. Each balun consists of two Lange couplers. Less than 0.3 dB and 2.5 degrees for the amplitude and phase balances, respectively, have been measured over the 1.0-2.2 GHz bandwidth for a microstrip balun. As compared with other reported baluns, these baluns are simpler, more compact, easier to design, and fabricated on only one side of the substrate. They are thus very attractive for microwave integrated circuit (MIC) and monolithic microwave integrated circuit (MMIC) applications.<>     

一种新型探地天线的优化设计

设计了一种新型超宽带平面天线.用FDTD研究了近地面天线的模拟计算问题,给出了天线的近场辐射性能.通过与平面蝶形偶极天线对比,结果表明该天线具有波形保真度好,对称的辐射方向图及后向辐射小等特点,进一步通过加载集中电阻优化设计,改善了天线的驻波特性.此天线不仅适用于探地雷达,还可以广泛地用于宽带通信和冲激雷达等系统.     

单纤三向器件平面光波导芯片结构优化设计

文章对采用平面光波导技术的单纤三向器件(Triplexer)芯片结构的参数进行了优化设计,对单元结构的光谱响应进行了模拟计算,通过数值模拟分析了结构的工艺容差性.结果表明,采用双模耦合器和M-z干涉仪结构可以得到工艺容差性高、光谱响应优良的适用的Triplexer器件.     

一种应用于WLAN的抗金属四频段平面单极天线设计

用于非金属外壳设备的常规天线与金属外壳设备一起使用,会导致完全不同的回波损耗。因此,提出了一种同时适用于金属外壳和非金属外壳设备的四频段平面单极天线,该天线由一个弯曲接地层、一对寄生贴片和由同轴馈电激发的辐射片组成。提出的天线能够在不同类型接地层影响下,保持其谐振频率一致性,甚至能够连接到金属外壳上。该天线适用于在WLAN 2.4/5.2/5.8 GHz、WiMAX 3.5/5.5 GHz和4.5GHz工作的多种应用。仿真和实际测量结果显示,即便是连接到较大的金属外壳或金属板时,提出天线能够较好地保持回波损耗和增益一致性且符合行业标准。     

Comments on "Surface wave enhanced broadband planar antenna for wireless applications"

For original paper see K.M.K.H. Leong et al., ibid., vol. 11, pp.62-4 (2001). The above paper claims to present "a new class of broadband antenna in which TE/sub 0/ surface-wave is used as the primary source of free space radiation". After reviewing the references, and analyzing the parameters published, it does not appear that the antenna can operate in the manner claimed.     

Design of an efficient miniaturized UHF planar antenna

The design aspects and the measured results of a novel miniaturized planar antenna are described. Such architectural antenna design is of great importance in mobile military communications where low visibility and high mobility are required. Slot radiating elements, having a planar geometry and capable of transmitting vertical polarization when placed nearly horizontal, are appropriate for the applications at hand. Slot antennas also have another useful property, so far as impedance matching is concerned. Basically, slot dipoles can easily be excited by a microstrip line and can be matched to arbitrary line impedances simply by moving the feed point along the slot. Antenna miniaturization can be achieved by using a high permittivity or permeability substrate and superstrate materials and/or using an appropriate antenna topology. We demonstrate miniaturization by designing an appropriate geometry for a resonant narrow slot antenna. A very efficient radiating element that occupies an area as small as 0.12/spl lambda//sub 0//spl times/0.12/spl lambda//sub 0/ is designed and tested. Simulation results, as well as the measured input impedance and radiation patterns of this antenna, are presented. This structure shows a measured gain of 0.5 dBi on FR4 substrate, which has a loss-tangent of the order of 0.01. Also, the effect of finite ground plane size on gain and resonant frequency is investigated experimentally.     

一种可用于体域网的小型化超宽带天线设计

基于FR4环氧板,设计了一种可用于体域网的非对称共面波导馈电的超宽带天线。该天线由Y型贴片、梯形地板和三叉戟共面馈线组成。Y型贴片、圆形贴片、三角形贴片实现4~5 GHz的中低频处带宽小于-10 d B的效果,梯形地板和三叉戟共面馈线实现7~14 GHz的高频处带宽小于-10 d B的效果。该天线采用非对称共面波导的馈电方式,具有良好的共面性与高度的集成性,使得天线的总体尺寸更小,辐射贴片的面积为22 mm×21 mm。与以往的小型化超宽带天线相比,该天线具有尺寸更小、带宽更宽的优势。经网络矢量分析仪测试结果表明,该天线在2. 14~11. 32 GHz的超宽带频段内回波损耗小于-10 d B(相对带宽为136. 4%),可适用于2. 4/5. 2/5. 8 GHz无线局域网、3. 5/5. 5 GHz WiMAX、LTE频段38和LTE频段40。同时,该天线距离人体大于5 mm时的比吸收率(SAR)小于2 W/kg,满足国际标准。     

The design and fabrication of planar multiband metallodielectric frequency selective surfaces for infrared applications

In this paper, micron-scale frequency selective surfaces (FSS) are presented for the first time that exhibit multiple strong stopbands (>10dB) in the far-infrared (IR). Fractal and genetic algorithm (GA) synthesis techniques are employed in the design of single-layer, multiband IR FSS. These designs have been fabricated on thin, flexible polyimide substrates and characterized using Fourier transform infrared (FTIR) spectroscopy. Measurements show excellent agreement with predictions from a periodic method of moments (PMoM) analysis technique that takes into account metallic and dielectric losses. Additional design constraints were incorporated into the GA in order to guarantee that the synthesized FSS structures could be accurately fabricated.     

Division-free duplex for wireless applications

Division-free duplex is proposed for future wireless systems, thus providing simultaneous duplex radio transmission on a division-free basis. The required duplex isolation can be achieved by electronic interference cancellation operating at both RF and baseband, with results from an experimental RF system yielding some 72 dB duplex isolation at 1.8 GHz for 200 kHz channelisation     

A novel design methodology for extended continuous class-F power amplifiers in wireless applications

Wireless Networks - In this paper, an extended continuous class-F power amplifier (PA) is investigated, designed, and fabricated. The new auxiliary parameter $$left(beta +alpha...     

Cooperative communications with relay selection for wireless networks: design issues and applications

Relay selection schemes for cooperative communications to achieve full cooperative diversity gains while maintaining spectral and energy efficiency have been extensively studied in a recent research. These schemes select only the best relay from multiple relaying candidates to cooperate with a communication link. In the present paper, we reviewed recently proposed cooperative communication protocols that integrate with relay selection mechanisms. The key design issues for relay selection mechanisms, for example, relaying candidate selection, optimal relay assignment, and cooperative transmission, were identified. We further discussed the challenges of optimal relay assignment in multi‐hop wireless sensor networks and presented the potential applications of cooperative communications with a relay selection in such networks. Future research directions were outlined, for example, the issues of service differentiation and system fairness in cooperative communication systems and the joint use of game theory and adaptive learning techniques in relaying candidate selection and optimal‐relay assignment mechanisms for efficient allocation of network resources. Copyright © 2011 John Wiley & Sons, Ltd.     

Author's reply [to Comment on "Surface wave enhanced broadband planar antenna for wireless applications"]

For original paper see K.M.K.H. Leong et al., ibid., vol.11, pp.62-64 (2001). For comment see T.J. Ellis, ibid., vol.13, no.6, pp.250-51 (2003). The authors appreciate the investigation and comments by T. J. Ellis regarding the quasi-Yagi antenna. In fact, one of the co-authors (Y. Qian) has been challenged multiple times in the past on the novelty of the quasi-Yagi antenna and feels obliged to take this opportunity to make some clarifications and re-emphasize the uniqueness of this particular antenna structure.     

Co-design of a wideband double-balanced active mixer and transformer-based baluns for 77 GHz radar applications

This paper presents a 130-nm BiCMOS active mixer dedicated to 77 GHz automotive radar applications. The architecture is based on a double-balanced Gilbert cell with integrated transformer-based baluns. Interconnections between devices, capacitor accesses and Tee-junctions are modeled using EM software in order to improve the simulation accuracy. Focusing on wideband operation, the transformer-based baluns are considered as part of the input matching network. Sizing of the transformer is detailed along with its amplitude and phase balance performances. The design of the input matching circuit integrating the transformer is presented, providing a 12-GHz bandwidth. Measured noise figure, conversion gain and compression point of the mixer are displayed and compared to the state of the art.     

Theoretic analysis of unique localization for wireless sensor networks

Node self-localization has become an essential requirement for realistic applications over wireless sensor networks (WSNs). Although many distributed localization algorithms have been proposed, fundamental theoretic analysis of unique localization is still in its early stage of development. This paper aims at a synthetic and homogeneous survey of the theoretical basis on WSN localization problem carried out thus far. Specifically, subsequent to establishing a technological context of relevant terms, we construct a graph and then a formation for each WSN to present current state-of-the-art by analyzing possible conditions for unique localization, as well as corresponding verification algorithms, by drawing on the powerful results from rigidity theory, distance geometry, geometric constraints in CAD, and combinatorial theory. We show that the unique localization problem is well understood in two-dimension, however, only partial analogous results are available in three-dimension.     

为低功耗无线应用选择天线

天线是RF系统中的一个重要组件,并且对性能有着重大的影响。高性能、小尺寸以及低成本是许多RF应用最常见的要求。为了满足这些要求,实施一个适当的天线并概括描述其性能特点是非常重要的。本文描述了典型的天线类型并阐述了选择天线时应该考试的重要参数。