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针对工作在UHF频段和微波频段的RFID系统(射频识别系统)要求,设计满足915MHz和2.45GHz多频特性的分型天线,提出采用方形Sierpinski毯结构。针对目前分型天线谐振频率所成的1∶3∶9的特性分析,并对天线部分参数改变,并对二阶毯型贴片天线进行开槽分析研究,提高天线性能,对高频部分降频以达到系统所要求915MHz和2.45GHz的中心频率,达到谐振频率的同时并保证理想的10dB回损带宽。 相似文献
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S频段大扫描角圆极化相控阵天线研制 总被引:1,自引:1,他引:0
设计了一套S频段圆极化相控阵天线,该相控阵天线采用9个微带贴片天线单元进行优化排列与旋转组阵实现。通过HFSS软件仿真,在辐射功率10 dBW的情况下,该相控阵天线在方位360o俯仰±80o的大扫描角范围内,具有大于15 dBW的等效全向辐射功率(EIRP),法向轴比在整个频带内平坦且小于0.5 dB。设计并装配好该相控阵天线后进行测试,得到扫描范围内大于15 dBW的EIRP值,同时测得法向轴比在整个频带内平坦且小于1 dB,测试值与仿真设计值吻合很好。 相似文献
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提出了一种适用于LoRa可穿戴设备的小型化双频段天线.该天线由半径为18 mm的基板及上方高6 mm的圆环支架构成,利用顺时环绕单极子、耦合分支在一定小型化的结构上激励出两个低频谐振模式,满足LoRa天线性能要求.实测天线-10 dB阻抗带宽为476~502 MHz和854~879 MHz,能够覆盖LoRa设备在470~510 MHz和863~868 MHz的大部分工作频段,同时在490 MHz和865 MHz两个工作频率点测得效率分别为15.56%和27.91%.该天线结构简单,覆盖频率广,体积小,工作频带内具有良好的辐射性能,具有一定的工程应用价值. 相似文献
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为了扩大射频识别系统阅读范围和提高识别效率,设计了一款应用于多标签高效读取的射频识别( RFID)波束扫描阵列天线。采用空气层结构设计出增益值为6 dBi的圆极化天线阵元并组成2×2平面天线阵,使用开关线型移相器与威尔金森(Wilkinson)功分器设计出天线馈电网络,并使用现场可编程门阵列(FPGA)模块控制阵元间相位变化,实现波束30°偏转。整体模型尺寸为350.0 mm×350.0 mm×5.7 mm,分别使用微波暗室、射频网络分析仪以及连接RFID阅读器测试,表明天线实现了4个方向波束偏转以及识别多个标签。 相似文献
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《Vehicular Technology, IEEE Transactions on》1986,35(2):57-62
Theoretical and experimental studies are made on radiation patterns of mobile antennas within the frequency range from 300 to 900 MHz. In order to calculate vertical plane patterns of quarter wavelength monopole and a half-wavelength dipole located on an automobile's roof, a theoretical model of an automobile body is developed, in conjunction with the geometrical theory of diffraction (GTD). The theoretical model consists of three-perfectly conducting plates. It is ascertained from a comparison between calculated and measured results for the feed point impedance and the radiation pattern that the effect of the body and the earth can be well examined with the theoretical model. The results of pattern calculation for the above two antennas show that the radiation patterns depend largely on the configuration of the automobile body and the earth condition. The technique described in this paper can be used as a design tool to estimate radiation performance of mobile antennas. 相似文献
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The element-gain paradox for a phased-array antenna 总被引:1,自引:0,他引:1
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A novel bi-directionally fed phased-array antenna (BiPA) is presented. A BiPA can operate at half the phase shift of the conventional antenna with the same performance, leading to smaller size and lower cost. Main components of a BiPA are antenna elements and variable impedance phase shifters (VIPSs). The VIPS consists of three resonant circuits that include variable capacitors, it is applicable for both functions as a power divider and as an impedance-matching device, since the input/output impedance and the phase shift can be independently varied. The BiPA with a VIPS is simulated and evaluated at a 2.45-GHz industrial-scientific-medical band. The measured results agree well with the simulated ones. The performances of the VIPSs are confirmed as 1.4 dB in insertion loss, and -17dB in return loss for a phase shift of 0/spl sim/80/spl deg/ with the control voltage from 0- to 3.5-V DC, and the measured radiation pattern of the BiPA is /spl plusmn/30/spl deg/ in the steering angle, 24/spl deg/ in beamwidth, and -9dB in the sidelobe. Furthermore, an enhancement of the sidelobe suppression can be expected by changing the power ratio of each antenna element. 相似文献
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A printed compact dipole antenna for dual ISM band (2.44 and 5 GHz) is presented. The proposed antenna fed by using a 50 /spl Omega/ coaxial line occupies a volume of 15/spl times/40/spl times/1 mm/sup 3/ (FR-4, permittivity 4.6). The impedance bandwidth for 10 dB return loss is about 400 MHz (from 2170 to 2570 MHz) at 2.4 GHz band and over 2300 MHz (from 4690 to beyond 7000 MHz) at 5 GHz band. The measured radiation gains range from 1.20 to 1.41 dBi at 2.4 GHz band and from 2.25 to 3.44 dBi at 5 GHz band, respectively. 相似文献
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The authors introduce three types of dual band antenna combining a slot and a parasitic wire. The slot and the parasitic wire are designed to become resonant at two different bands. The antenna characteristics are calculated by the method of moments; calculated VSWRs are in good agreement with measured data 相似文献
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Law D.C. Khorrami J.R. Sessions W.B. Shanahan M.K. 《Antennas and Propagation Magazine, IEEE》1997,39(5):88-93
The radiation patterns of a 404-MHz phased-array-radar antenna were measured relative to a reference dipole antenna, using 406-MHz repeaters on polar-orbiting satellites and associated ground-station equipment. More than 6000 measurements were collected from the three radar-antenna beams over a five-month period in 1995. The patterns were compared with those derived from measurements of the complex current distributions on the coaxial collinear radiating elements of the antenna. In addition to verifying the antenna specifications for gain, beamwidth, pointing direction, and sidelobe levels, the far-field satellite repeater measurements validated the convenient and inexpensive current measurement and model technique, developed for antenna testing and maintenance 相似文献
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Simulation of a phased-array antenna in waveguide 总被引:1,自引:0,他引:1
A method has been developed for simulating a large planar phased-array antenna in order to determine the performance of its radiating elements. By simple measurements of a few elements inside of waveguides, their performance in the antenna array as a function of frequency, scan angle, and polarization may be determined. The number of elements that need to be constructed is small, and the method is well-suited to economical, empirical design of an element for an array having a very large number of elements. For this purpose, such an array is well represented by the infinite array which results from imaging by the waveguide walls. Five waveguide simulators, sampling five significant combinations of scan angle and polarization, have been developed for a particular array comprising circular elements in a square arrangement. The array impedance has been measured in the simulators, and from these measurements the reflection loss of the array has been calculated. An equivalent circuit for the element in the array has been obtained from two simple waveguide-impedance measurements, and the active impedance of the elements has been determined therefrom. Finally, these results have been employed to determine the behavior of the elements when the array is excited for circular polarization; the departure from circularity of the radiated polarization, as well as the reflection in both senses of circular polarization, have been obtained. 相似文献
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A simple linearly polarised dielectric-loaded horn with high aperture efficiency over two separate frequency bands is presented. The horn operates as a fundamental-mode dielectric-lined horn at the low frequency, and as a dual mode horn at the high frequency. Aperture efficiency better than 92.7% has been measured over the dual 4/6 GHz frequency band. 相似文献
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《Vehicular Technology, IEEE Transactions on》1967,16(1):10-14
Experimental measurements of mobile radio transmission have been made in a suburban area at 0.836 GHz and 11.2 GHz. The results are presented in terms of average transmission loss, level crossing rates, power spectra, average duration of fades, and probability distributions. Fading rates were predictably higher at 11.2 GHz but the average excess path loss over the free space calculation was comparable to the values obtained at UHF, lending encouragement to possible exploitation of the higher microwave bands for mobile radio. 相似文献
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This communication addresses the problem of estimating the minimum size a phased-array antenna must have in order that analyses based on simple infinite-array models yield meaningful results. The measure of array size proposed herein is an efficiency parameter defined for an infinite array with truncated excitations. Numerical results are presented for arrays of slots and dipoles, showing the rate of convergence of the efficiency parameter for various spacings and scan angles. The conclusions deduced from this analysis as to the minimum array size are in substantial agreement with exact computations dealing with finite arrays published in the literature. 相似文献
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简述了远场直接法测量有源相控阵天线EIRP的原理方法,推导出EIRP测量的原理方程。对EIRP测量误差进行了分析,结果表明其均方根误差≤±0.452 dB。最后给出了某工程应用的S波段相控阵天线的EIRP测量结果,测量结果同理论预算基本吻合。 相似文献