Triple Band Annular Ring Loaded Stacked Circular Patch Microstrip Antenna

In this paper a novel structure of annular ring loaded stacked circular patch microstrip antenna is theoretically analysed to observe various parameters such as return loss, input impedance, gain, directivity and radiation pattern. It is found that antenna possess three band of operation which signify the compactness and multiband operation of antenna. The antenna is resonating at three operating frequencies 1.720, 2.950, 3.060 GHz. The proposed theory is verified by simulation using Ansoft’s HFSS and theoretical results are in good agreement with simulated results. The antenna is useful for multi-services operations such as WLAN, GSM, UMTS, and WiMAX services.     

带反射腔的分布式电阻加载探地雷达天线设计与分析

该文研究了一种半椭圆结构分布式加载偶极子天线.通过改进天线臂结构以及采用分布式电阻加载,有效降低电流在天线末端的反射,能够改进天线的输入阻抗特性,展宽天线的工作频带.应用长方体金属反射腔,减小了天线的后向辐射,增强了天线的地下穿透能力.利用电磁计算软件对天线进行了仿真和设计,并加工制作了一部样机,测试了样机的反射损耗和辐射特性等性能参数,测试与仿真结果较为贴合.将该天线应用于探地雷达系统进行地下目标探测实验,实验结果证明该天线满足探地雷达系统的需要.      

分形开槽减缩微带天线RCS

分形由于其独特的结构及性能早已在天线的设计中有所应用,但较少地应用于天线雷达散射截面减缩。本文首次将分形思想应用到开槽微带天线中。设计了一副分形开槽微带天线,与常规微带天线相比,在辐射性能降低不多的同时较好地实现了整个频带RCS减缩。     

一种新颖的宽带高增益车载全向天线

介绍了一种工作在225～800MHz的双锥柱形超宽带垂直极化全向天线结构。在两天线单元之间加同轴电缆扼流圈替代传统的0．25A0扼流杯,并在天线底部加同轴电缆扼流圈和用Г匹配方式给两天线单元馈电的方法,完成了一种具有4个倍频程的超宽带垂直极化全向天线。该天线具有良好的匹配性能和辐射特性,有效的克服了一般超宽带全向天线垂直面辐射方向图主波瓣容易偏离水平面的不足。     

Slits and slots arrayed built-in antenna with large-offset dual-point feed line

Described is a novel structure of a various-size slits and slots arrayed antenna using a large offset dual-point feed line, which has similar radiation pattern properties. In this case, the large-offset dual point feed line leads to good impedance matching in a wide frequency band. Inserted variable size slits and slots arrayed on the radiator act as a multi-band resonant element of the antenna. Experimental results of a constructed prototype covering the usable bandwidth of the DCS, PCS, IMT 2000 operations are presented.     

Reconfigurable Tri-Band UWB Antenna Using Single Winding Balun Structure

Wireless Personal Communications - This paper proposes a novel tri-band reconfigurable UWB antenna using a balun structure. The proposed UWB antenna achieves tri-band frequency of operation in two...     

Double MOS Loaded Circular Microstrip Antenna with Airgap for Mobile Communication

A novel model of a wide frequency range double MOS loaded circular microstrip patch antenna with airgap between ground plane and substrate is proposed. In this structure two metal oxide semiconductor (MOS) devices are loaded on the patch to enhance the operating frequency range of antenna. To investigate the antenna, different parameters such as resonance frequency, input impedance, frequency agility, VSWR, radiation pattern etc. are calculated and simulated. The resonant frequency of proposed 10 mm radius patch is upward shifted from 5.2 to 6.8 GHz using 1 mm airgap and by loading MOS, antenna can be tuned down to 1.27 GHz operating frequency, which leads to compactness and tunability of antenna. Proposed antenna can be tuned between 1.27 and 6.8 GHz frequency of operation which makes the antenna highly suitable for wide frequency range of mobile communication. The proposed double MOS loaded antenna possessed 82.94 % frequency agility. The antenna is worth for GPS, WLAN, UMTS, and WiMAX operations.     

改进型Sierpinski三角形分形多频天线研究

分形天线可以实现多频工作和尺寸减缩,在军用与民用方面都有着很大的发展潜力.研究了一种新结构形式的改进型Sierpinski分形天线,与普通结构相比,其可以通过调节各个三角形的高度比例来调整频比,且结构简单,加工制作更容易.仿真结果验证了改进型Sierpinski多三角形天线的多频特性.     

Conformal Antennas on Liquid Crystalline Polymer Based Rigid-Flex Substrates Integrated With the Front-End Module

Recent developments in liquid crystalline polymer (LCP)-based processing technology have shown that highly-integrated, fully-packaged radio-frequency (RF) front-end modules with high-performance can be designed by using the system-on-package (SOP) approach. However, the direct integration of a large antenna element to a small module package still remains an issue. This paper presents a novel conformal antenna structure, which results in a compact integration of the antenna and the module package for 5 GHz WLAN/WiMAX applications. The extension of 5 GHz single-band operation to 2.4/5 GHz dual-band operation is also discussed in this paper. The antenna is an inverse L-shaped monopole printed on a 25-$mu{hbox {m}}$-thick flexible LCP layer, which protrudes from a rigid multilayer organic substrate. The shielding effects of a grounded metal case, which can house the associated module circuitry, are also considered during the design process. The metal case serves as a vertical ground plane for the antenna in addition to protecting the module circuitry from the near-fields of the antenna. The flexible LCP substrate can be bent and folded over the module case, resulting in a compact design and the tight integration of the antenna with the front-end module. The details of the design and the fabrication of the proposed structure as well as the simulation and the measurement data are presented in this paper.      

Directional reconfigurable antennas on laptop computers: Simulation, measurement and evaluation of candidate integration positions

This study reports on the integration of a novel reconfigurable microstrip antenna capable of reconfiguring both its radiation pattern and frequency response onto a generic laptop computer structure. The purpose of such an exercise is to provide the relevant information necessary to integrate high performance antennas onto structures that can be used in ad hoc communication scenarios as well as other demanding applications. To pre-evaluate candidate antenna locations on the laptop chassis, an electromagnetic visibility study (EVS) is performed. Once integrated into candidate positions that have been analyzed by the EVS, the operation of the antenna on the host structure is measured and assessed with consideration to several realistic electromagnetic environments. The resulting performance and packaging issues are discussed. A formalized procedure for the integration of the antenna onto any host chassis using the EVS as a tool is also included.     

Analysis of Modified Square Sierpinski Gasket fractal microstrip antenna for Wireless communications

In this paper, the slot loaded microstrip antenna has been developed with Sierpinski gasket technique. The proposed Modified Square Sierpinski Gasket (MSSG) fractal antenna involves a square patch utilizing Sierpinski gasket (triangular) structure. Four triangular slots are loaded at each iteration. The structure is then simulated using commercially available Ansoft HFSS simulator. The multi-band operation has been achieved by the proposed antenna at 15.915 GHz, 20.045 GHz, 23.077 GHz, 27.77 GHz frequencies with −20 dB, −25 dB, −22 dB, −28 dB return loss respectively which works well for Ku (12–18 GHz) and K (18–27 GHz) band. The consistent result is obtained after simulation and the validity of fabricated design is checked by the measured result. The designed antenna is an attractive candidate for applications like wireless multi-band communication systems.     

卫星导航复合多功能桅杆天线的研究

本文利用双寄生套筒的结构,采用双锥和粗振子结合的辐射体形式设计了一款可与卫导天线级联的全向宽带穿杆天线。采用这种特殊结构该天线解决了常规天线内部穿金属接地杆后驻波恶化的问题。仿真和实测结果表明天线在120-550MHz频带内电压驻波比小于2.5,且高低频端的方向图全向性良好。     

Efficiency calculation of feed structures and optimum number of antenna elements in a subarray for highest G/T

For an antenna array, different feed structure topologies may yield the same radiation characteristics. However, different topologies may result in different efficiency and noise performance. In this paper, parallel arm antenna arrays are analyzed for efficiency and noise temperature using the noise equivalent line length method (NELL) with the number of antenna elements in a subarray as a parameter. It is shown that efficiency of an antenna array feed structure as well as its noise temperature can be calculated using the NELL method. The comparison of the two parameters, efficiency and noise temperature, yield the optimum number of antenna elements in a subarray of a parallel arm antenna array for the highest G/T ratio.     

Narrow flat-plate antenna for 2.4 GHz WLAN operation

A novel flat-plate antenna, obtained by cutting an inverted-L slit in a narrow metal plate or by stamping from a metal sheet, for wireless local area network (WLAN) operation in the 2.4 GHz band (2400-2484 MHz) is presented. The antenna has a simple structure and is easily fed by using a 50 /spl Omega/ coaxial feed line. A prototype of the proposed antenna with a narrow width of 3 mm is constructed and studied.     

Dual frequency planar antenna at S and X bands

A new configuration of patch antenna is introduced, which provides a dual-band operation. This structure consists of an S-band cross patch with four square patches printed in the empty spaces among the arms of the cross. These patches provide a subarray working at X-band. This structure is simple to design and offers the advantage that it can be printed on a single-layer. An array geometry designed by using the above structure, is suggested. This can be suitable for satisfying the requirements of a typical dual-frequency SAR antenna     

Circularly Polarized Square Ring Slot Antenna with Arrow‐Shaped Structure

A novel design of a compact square‐ring slot microstrip antenna for achieving circular polarization (CP) operation is proposed and experimentally studied. By using an arrow‐shaped slot structure as a radiating element, the resonant frequency of the proposed antenna is significantly lowered, which can lead to a large size reduction for fixed frequency operation. The CP radiation characteristics are achieved by loading with proper asymmetry, which can be placed diagonally. A prototype of the proposed design is implemented and its performance is measured. Measured results show that radiation patterns with good CP characteristics are obtained at the resonant frequency.     

超宽带多极化跟踪天线及馈源的设计

随着空间技术的快速发展,对目标飞行器的跟踪与信息截获变得越来越重要。为了实现对目标飞行器的跟踪和信息截获,文中设计了一种超宽带、多极化、高增益的跟踪天线及馈源,采用基于印制板设计的对数周期天线作为单元,并使用八个单元组成圆环阵作为反射面天线的馈源,对结构和馈电幅相进行设计,从而实现线极化比幅跟踪、左旋圆极化接收、右旋圆极化接收三种工作方式。仿真结果表明:单元天线驻波小于2的相对带宽达到147%,次级方向图的圆极化轴比小于4 dB,交叉波束的交叉电平基本稳定在-3 dB~-8 dB。对该跟踪天线进行加工,并进行天线系统测试,实际测试结果与仿真吻合很好。     

Compact circularly-polarised circular microstrip antenna withcross-slot and peripheral cuts

Novel compact circular-polarisation (CP) operation of a circular microstrip antenna, with a cross-slot in the patch centre and a pair of peripheral cuts at opposite sides of the patch boundary, is proposed and experimentally studied. For operation at a fixed frequency, the proposed antenna using a single probe feed, can have an antenna size reduction of ~20% as compared to regular size CP operation of a circular microstrip antenna. Details of the experimental results are presented and analysed     

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.     

Dual-band and dual-polarised horn antenna including conical helix

A horn antenna having dual-band and dual-polarisation operation is proposed. To implement a small-sized structure providing circular polarisations in the Ka- and K-band, the antenna is designed using the horn radiator on the basis of a conical helix which is exited by two ports for TX and RX in both ends. Through a design optimisation process, a compact dual-band and dual-polarised horn antenna having high gain and high isolation performance was realised