共查询到20条相似文献，搜索用时 31 毫秒
1.
在综合分析了微带平面天线阵列馈电网络的两种传统馈电方式的基础上,提出了一种在微波工程应用中实际使用的一种新型馈电网络,提高学生理论知识与实践相结合的能力,更好的掌握最新技术发展。其新型馈电网络由一种左-右手混合微带传输线构成,可以获得高于传统并联馈电网络的天线阵列增益;同时,可以修正传统串联馈电网络的天线阵列辐射方向图的波束偏移,给出了一个工作频率为35GHz的2×2微带面阵的馈电网络设计案例,验证了其理论的正确性。 相似文献
2.
给出了一种紧凑的可用于WUSB的新型带陷超宽带印刷单极子天线．天线由内嵌条带的U形环组成并采用部分接地技术,从而使天线具有带陷超宽带特性．实测结果表明该天线输入端驻波比小于2的绝对阻抗带宽为7．88GHz,覆盖了3．12～11GHz的频率范围,其中5．06～5．89GHz范围内具有带阻特性．讨论了各几何参数对天线性能的影响,同时获得了该天线相对稳定的、近似全向且对称的测试方向图．由于此种天线无需额外的带阻滤波器来隔离天线与其他通信系统的干扰,从而大大简化了WUSB系统的设计． 相似文献
3.
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
4.
在圆柱形介质谐振器天线单元分析的基础上,设计了一种4单元介质谐振器天线阵列。天线阵采用微带线馈电网络,保证单元之间满足相位匹配关系,使该天线阵列具有良好的定向辐射特性,而且在带宽方面满足要求。 相似文献
5.
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
6.
Mohammed Ahmed ZHONG Shun shi 《上海大学学报(英文版)》1999,3(4):279-281
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ Ｔｈｅｓｕｃｃｅｓｓｆｕｌｃｏｍｍｅｒｉｃａｌａｐｐｌｉｃａｔｉｏｎｓｏｆｗｉｒｅｌｅｓｓｔｅｃｈｎｏｌｏｇｙｄｅｍａｎｄａｐｐｒｏｐｒｉａｔｅａｎｔｅｎｎａｓ．Ｔｙｐｉｃａｌｌｙ,ａｄｕａｌｐｏｌａｒｉｚａｔｉｏｎｏｐｅｒａｔｉｏｎｓｕｃｈａｓｓｉｍｕｌｔａｎｅｏｕｓｖｅｒｔｉａｌａｎｄｈｏｒｉｚｏｎｔａｌｐｏｌａｒｉｚａｔｉｏｎａｎｔｅｎｎａｗｉｔｈｌｏｗｐｒｏｆｉｌｅ,ｓｍａｌｌｓｉｚｅ,ａｎｄｌｉｇｈｔｗｅｉｇｈｔｉｓｒｅｑｕｉｒｅｄｆｏｒｗｉｄｅｓｐｒｅ… 相似文献
7.
为了拓展渐变槽线天线的工作频带,提出一种采用共面波导新型馈电结构的双面印刷对跖型渐变槽线天线.基于对渐变槽线天线之宽频带特性受限于现有馈电方式的分析,改用蚀刻于背板的共面波导至双面印刷对跖渐变槽线的行波式转接.其仿真和实验结果一致表明:该馈电方式使天线的阻抗具有高通频响特性,且保持较好的辐射方向性图,在3 GHz以上的... 相似文献
8.
设计了一种多分支平面印刷天线,采用微带线馈电方式,其中微带线设计成T形,与辐射单元匹配.辐射单元由3个L形的金属面结构构成,其分别工作在2.4 GHz、3.5 GHz和5.4 GHz,可应用于无线局域网（WLAN）和全球微波互联接（WiMAX）系统.通过电磁仿真软件HFSS对这种天线进行设计,在WLAN应用频段上10 dB阻抗带宽分别为1 GHz （4.9～5.9 GHz）和310 MHz （2.24～2.55 GHz）;在WiMAX应用频段上10 dB阻抗带宽380 MHz （3.3～3.68 GHz）.实测结果表明,这种天线具有良好的远场辐射特性,其增益在2.5～4.7 dBi之间. 相似文献
9.
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
10.
A bidirectional deployable parabolic cylindrical reflector for an L-band synthetic aperture radar is presented in this study, in which a self-deployed antenna with low weight was designed. The antenna consists of four curved surfaces formed from thin sheets of composite materials connected by hinges along the edges, and the reflective surface is provided by the front surface. The edge profiles of connecting lines were obtained through geometric analysis. A scaled model, including design and manufac- ture, was demonstrated to validate the process from the folded state to the fully deployed state. The non-contact synchronous vision measuring method was used to test the basic frequency of the scaled model, and the test results gave the verification of the analyses. Compared with the existing unidirectional deployable antenna, this new type of bidirectional deployable antenna can be applied to larger-size antennas and has better performance because the glass-woven tape connections were substituted with more reliable hinges. Static, modal, harmonic response, and transient response analyses of the full-sized reflector structure were mod- eled with the commercial finite element （FE） package ABAQUS. The modeling techniques were developed to predict the struc- tural dynamic behavior of the reflector and the results showed that the first natural frequency was 0.865 Hz, and the reflector structure had good stiffness in three directions. This proposed structure has very high stiffness-to-mass ratio because of its hollow solid construction. A preliminary simulation of radiation properties of the parabolic cylindrical antenna, fed by an off-set linear feed horn array, was conducted to obtain the radiation pattern of the feed and the reflector. 相似文献
11.
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
12.
天线实验教学仿真系统的研究 总被引：4，自引：0，他引：4
采用Visual Basic软件开发工具设计并实现了天线实验教学仿真系统。首先给出了系统的构成,讨论了天线模型的建立、天线方向性图和天线输入阻抗的测量,最后介绍了系统的软件实现过程。所设计的天线实验教学仿真系统实现了天线的方向性图和输入阻抗的测量过程。应用表明,天线实验教学仿真系统具有交互性好、实用和逼真等特点。 相似文献
13.
A new structure of dielectric waveguide for millimeter waveband namedgroove nonradiative dielectric(GNRD)waveguide and a leakywave antenna based on thisstructure are developed in this paper.The GNRD structure overcomes the difficulty of as-sembling precisely the dielectric strip in the nonradiative dielectric(NRD)structure.Thedispersion characteristics of the GNRD waveguide,and the propagation and radiationcharacteristics of the GNRD leakywave antcnna have been analysed by the use of thetransverse rcsonance mcthod.The theoretical results are in good agreement with the exper-imental data. 相似文献
14.
A compact wideband microstrip array antenna with a squint beam is introduced without the matched load. Its measured beam is
at 10° offset to the broadside with a measured gain of 12 dB at 10 GHz. The measured impedance bandwidth (voltage standing
wave ratio (VSWR)⩽2) is over 16%, which agrees well with the simulated one. It is a low-cost wideband design with compact
simple structure, suited for military and commercial application. 相似文献
15.
YU Yong-jun YANG Shi-zhong 《重庆大学学报(英文版)》2006,5(1):24-26
1 Introduction In recent years, the need for ultra-wideband (UWB) antenna with an omni-directional coverage and compact antenna geometry increases in many applications, for example the Federal Communications Commission (FCC) released the unlicensed freque… 相似文献
16.
为了适应全球卫星定位系统的需要,采用多层重叠的贴片结构,设计了一种双频圆极化天线。其中上层贴片为圆形,下层为矩形,利用开槽技术分别在1．618GHz和2．49GHz频段处实现了圆极化,并且通过在下层贴片的四条边上分别开设矩形槽达到了缩小天线尺寸的目的。同时采用单点同轴馈电,实现了良好的阻抗匹配性能。 相似文献
17.
本文在基片集成波导腔体结构的基础上,结合共地共面波导结构,提出了一种低剖面带宽增强型背腔缝隙天线．本天线兼具传统金属波导缝隙天线辐射效率高、功率容量大以及传统微带缝隙天线体积较小的优点,同时还具有了低剖面、重量轻、易于与平面电路集成的特点．仿真结果显示,该天线中心工作频率为5．8GHz,最大增益6．9dBi,相对带宽2．25％,完全覆盖5．8GHz频段,适用于RFID应用． 相似文献
18.
为了实现双频天线的小型化,对平面倒F形天线给出一种改进,在辐射贴片上开一个T形槽．再将它的尾部向内折叠。通过与L形开槽的倒F形天线相比表明：改进后天线的结构更加紧凑,尺寸减小30％以上,且在给定的工作频段具有良好的辐射特性。 相似文献
19.
用于通信的超宽带印刷天线 总被引：1，自引：1，他引：1
1IntroductionUltra-wideband(UWB)microwave antennas are ofinterest for a variety of applications such as electroniccountermeasure,transient radars,mine detection,andunexploded ordnance(UXO)location and identifica-tion.In the early2002,the release of the UWB forcommercial communications by the Federal Communi-cation Commission(FCC,USA)sparked renewed in-terest in the subject of UWB antennas.Conventional UWB antennas such as log-periodic orspiral antennas exhibit good UWB characteristi… 相似文献
20.
李秋生 《赣南师范学院学报》2006,27(6):7-10
相位量化将引起相控阵天线峰值副瓣电平恶化、波束偏离预定指向等问题,合理选择馈相方法是降低其影响的关键．文中在给出数字馈相通用数学模型的基础上,以二可能值法为例,对四舍五入、完全随机和部分随机等馈相方法进行了蒙特卡洛仿真和分析．仿真结果表明,在完全随机馈相的基础上,部分随机馈相能进一步改善相控阵天线副瓣电平和波瓣指向等关键的波瓣性能指标,并且不明显增加原有馈相方法的运算量,适于在实际应用中加以推广． 相似文献