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1.
Characteristics of a single-feed dual-frequency bow-tie microstrip antenna are studied. By using the variation method, simple formulas for resonant frequencies of the bow-tie microstrip antenna are derived. It is shown that the dual-frequency ratio can be controlled easily by choosing the parameters of the antenna. This design gives compact antenna size and simple antenna structure. Experimental results are presented, verifying the validity of the design. 相似文献
2.
INTRODUCTIONInvestigationofphotonicbandgap(PBG)materialsiscurrentlyoneofthemostactivefron-tiersinengineeringandphysics.PBGmaterialshaverecentlyemergedasanewmultidisciplinaryfieldofstudy(Kesleretal.,1996;Yablonovitch,1994;SimovskiandHe,2001).APBGstructurecanhaveabandgapwithinwhichelectromagnetic(EM)wavepropagationispreventedinalldirec-tions(Joannopoulosetal.,1997;Ozbayetal.,1994).Foratwo-dimensionalPBGmaterial,thepropagationofanEMwavewithinitsbandgapispreventedinalldirectionswithin… 相似文献
3.
ZHU Fang-ming HU Jun 《浙江大学学报(A卷英文版)》2007,8(2):192-196
INTRODUCTION Metamaterials are periodic metallic structures exhibiting unique properties not existing in natural materials. They are also called backward wave mate- rials, double negative materials, or left-handed mate- rials (LHM) in particular, in which the vectors E, H and k form a left-handed system. Since the idea pro- posed by Veselago (1968), metamaterials have at- tracted great interest in the last years (Smith et al., 2000; Pendry, 2000; Smith and Kroll, 2000; Shelby et al., … 相似文献
4.
A new photonic bandgap (PBG) cover for a patch antenna with a photonic bandgap substrate is introduced. The plane wave expansion
method and the FDTD method were used to calculate such an antenna system. Numerical results for the input return loss, radiation
pattern, surface wave, and the directivity of the antennas are presented. A comparison between the conventional patch antenna
and the new PBG antenna is given. It is shown that the new PBG cover is very efficient for improving the radiation directivity.
The physical reasons for the improvement are also given.
Project supported by the National Natural Science Foundation of China (No. 90101024) and the Science and Technologies of Zhejiang
Provinc (No. ZD0002) 相似文献
5.
A simple and compact ultra wideband (UWB) printed monopole antenna with band-notched performance is proposed in this paper. The antenna is partially grounded so that the Q value is depressed and the impedance bandwidth is broadened. A small strip bar is loaded on each arm of the similar U-shaped radiator. The impedance bandwidth of the antenna overlap with IEEE 802.11a is rejected consequently. The geometry parameters of the antenna are investigated and optimized with HFSS. The measured bandwidth of the proposed antenna occupies about 7.89 GHz covering from 3.05 GHz to 10.94 GHz with expected notched band from 4.96 GHz to 5.98 GHz. A quasi-omnidirectional and quasi-symmetrical radiation pattern in the whole band is also obtained. As a result, a UWB wireless communication system can be simplified with the band-notched UWB antenna presented. 相似文献
6.
吴瑞坤 《福建师大福清分校学报》2014,(5):1-4
论文中提出了一种基于复合左右手结构的零阶谐振小型天线,由四个等腰三角形贴片对称排列而成。使用软件仿真和优化得到天线零阶谐振频率为4.7GHz,并给出了各单元的具体参数。仿真结果,在中心频率4.7GHz处,天线的电压驻波比为1.16,天线增益为6.8dB,半功率波瓣宽度为83.1度。 相似文献
7.
结合实际,从理论分析的角度,探讨了仅在有线电视系统的前端,通过选择电视接收天线的方向、架设高度和位置以及采用差值接收天线和加强接收天线的屏蔽等办法来抑制电视同频干扰的问题. 相似文献
8.
结合实际,从理论分析的角度,探讨了仅在有线电视系统的前端,通过选择电视接收天线的趋向、架设高度和位置以及采用差值接收天线和加强接收天线的屏蔽等办法来抑制电视同频干扰的问题。 相似文献
9.
给出了一种处理宽带天线双端匹配的改进方法,即最优化算法,并且与实频法进行对比分析,最终可以明显地看出优化设计法原理简单,方法直观,设计方便,更适合宽带天线阻抗匹配网络的设计,最后用实例说明改进方法的可行性及优越性。 相似文献
10.
The Fabry-Perot resonator (FPR) antenna has found wide applications in microwave and millimeter waves and recently attracted considerable interest, in this paper, a summary of planar and cylindrical structures, analytic models and research development is presented, and a comparison between these structures and analytic models is made, showing that such analytic models as the FP cavity mode, electromagnetic band gap (EBG) defect mode, transmission line mode, and leaky-wave mode are consistent when applied to analyze this type of resonator antenna. Some interesting topics under recent research, including dual or multi-band, improvement of gain bandwidth, low profile and beam control, are surveyed. 相似文献
11.
讨论了二维轴对称柱坐标系中的FDTD亚网格技术（粗细网格比为3）及粗细网格边界的反射系数的测试方法。经测试计算，粗细网格边界的反射系数小于－36dB，计算例子表明所编程序的稳定性很好。 相似文献
12.
ZHONGShun－shi CUIJun－hai 《上海大学学报(英文版)》2001,5(4):295-298
This paper presents a new design of dual polarized aperture-coupled printed antenna array,The finite-difference time-do-main(FDTD) analysis of an aperture-coupled microstrip element is performed,and the effects of antenna parameters on ist characteristics are obtained to guide the design of the printed array,Then an 8^2 dual polarized array design in X-band is introduced with configuration plots,In order to improve its isolation and cross polarization.an outphase-displacement feeding technique is adopted in the feed network.Also,the round bends are used instead of conventional right-angle bends so as to acieve better VSWR performance,Experimental results are presented.indicating the validity of the design.This dual polarized array can be applied as a sub-array of paceborne SAR systems. 相似文献
13.
A low-sidelobe circularly-polarized （CP） microstrip patch array for 2.4 GHz radio frequency identification （RFID） readers is presented. The antenna array with a Chebyshev current distribution is composed of 6 microstrip elements. The CP operation is obtained by the quasi-square patch with difference in lengths of the two sides. The antenna has been investigated numerically and experimentally. Measured results show that the array has a Chebyshev pattern with the sidelobe level of -23 dB, the half-power beamwidth of 16° and an impedance bandwidth （S11 ≥-10 dB） of 130 MHz, which is suitable for RFID reader applications. 相似文献
14.
王瑞 《西安文理学院学报》2014,(3):55-57
提出了一种基于圆形缝隙结构的双频超宽带微带天线.通过在圆形缝隙内加载椭圆形贴片使得天线在获得双频超宽带特性的同时又保持了很小的物理尺寸.仿真结果表明,该天线的-10 dB阻抗带宽分别为2.1~4.0 GHz和5.2~8.8 GHz,天线的相对带宽分别达到了62.3%和51.4%,覆盖了无线局域网(WLAN)的2.45 GHz、5.20 GHz和5.80 GHz三个频段以及宽带互通微波接入(WiMAX)的2.50 GHz和5.25 GHz两个频段.在通带范围内,有良好的辐射特性,并且天线的尺寸为35 mm×35 mm×1 mm,便于集成在电路系统中. 相似文献
15.
将一种改进的遗传算法用于MIMO天线阵的优化,分析了容量与相关性的关系.在均匀线阵与均匀圆阵的相关性模型上,比较达波角、扩展角及天线间距对于相关性的影响.运用遗传算法,对构建的相关系数组成的矩阵进行分析, 给出定长非均匀4元线阵与圆阵在最小相关性下的天线阵分布. 相似文献
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17.
Research progress on Fabry-Perot resonator antenna 总被引：1，自引：0，他引：1
The Fabry-Perot resonator （FPR） antenna has found wide applications in microwave and millimeter waves and recently attracted considerable interest. In this paper, a summary of planar and cylindrical structures, analytic models and research development is presented, and a comparison between these structures and analytic models is made, showing that such analytic models as the FP cavity mode, electromagnetic band gap （EBG） defect mode, transmission line mode, and leaky-wave mode are consistent when applied to analyze this type of resonator antenna. Some interesting topics under recent research, including dual or multi-band, improvement of gain bandwidth, low profile and beam control, are surveyed. 相似文献
18.
HUANG Biao YAN Guo-zheng LI Qian-ru 《浙江大学学报(A卷英文版)》2007,8(10):1560-1567
Antenna is very crucial to radiotelemetry capsules which can measure the physiological parameters of the gastroin- testinal (GI) tract. The objective of this paper is to design a novel spiral slots microstrip patch antenna for the radiotelemetry capsules communicating with external recorder at 915 MHz located in ISM (Industry, Science, and Medical) bands. The microstrip patch antenna is designed and evaluated using the finite-difference time-domain (FDTD) method. Return loss characteristics and the effect of the human body on resonant frequency are analyzed, and the performances of radiation patterns at different positions of the human alimentary tract are also estimated. Finally, specific absorption rate (SAR) computations are performed, and the peak 1-g and 10-g SAR values are calculated. According to the peak SAR values, the maximum delivered power for the designed antenna was found so that the SAR values of the antenna satisfy the ANSI (American National Standards Institute) limitations. 相似文献
19.
卫星电视数字压缩频道的接收 总被引：1，自引：1，他引：0
林培通 《宁德师专学报(自然科学版)》1999,(4)
以宁德（１１９ ．５１°Ｅ,２６．６６°Ｎ） 接收亚洲２ 号（１００ ．５°Ｅ） 上的福建东南台节目为例,介绍数字卫星电视接收天线口径的计算方法以及怎样接收好数字卫星电视节目． 相似文献
20.
综合口径雷达的宽频带双极化口径耦合微带阵 总被引：1，自引：0，他引：1
An 8×1-element wideband dual-polarized slot-coupled microstrip antenna array with high isolation and low cross-polarization in X-band is presented. The array antenna offers an impedance bandwidth (VSWR≤2) of 23% and 21% for dual polarization ports, respectively. The measured isolation between two polarization ports is better than 35 dB and the measured cross-polarization level below -25 dB in the main beam over the operation frequency band of 9.35 GHz to 9.75 GHz. This array is well suitable for X-band SAR (synthetic aperture radar) antenna application. 相似文献