共查询到20条相似文献,搜索用时 31 毫秒
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Wen-Jun Lu William S.W. Cheung Yong Cheng Hong-Bo Zhu 《International Journal of Electronics》2013,100(9):1263-1279
A novel antipodal wide-slot antenna for ultra-wideband (UWB) applications is proposed and studied in detail. The antenna is fed by a microstrip line terminated with a rectangular tuning patch. An antipodal structure is employed to improve the radiation performances. The return losses, surface E-field, current distribution, radiation patterns and gains of the antenna are numerically and experimentally investigated. Results show that the proposed antipodal antenna has an impedance bandwidth from 0.79 to 4.0?GHz, which is about 5:1. Compared with conventional rectangular wide-slot antenna, more stable radiation pattern with lower cross-polarisation level and flatter gain variation over a 3:1 bandwidth can be obtained. Thus, the proposed antenna should be more suitable for future UWB-multiple-input multiple-output applications using polarisation diversity than conventional UWB rectangular slot antennas. 相似文献
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Yo-Sheng Lin Chun-Hao Hu Chi-Ho Chang Ping-Chang Tsao 《International Journal of Electronics》2018,105(6):993-1010
In this work, we demonstrate novel one-dimensional (1D) and two-dimensional (2D) antenna arrays for both microwave wireless power transfer (MWPT) systems and dual-antenna transceivers. The antenna array can be used as the MWPT receiving antenna of an integrated MWPT and Bluetooth (BLE) communication module (MWPT-BLE module) for smart CNC (computer numerical control) spindle incorporated with the cloud computing system SkyMars. The 2D antenna array has n rows of 1 × m 1D array, and each array is composed of multiple (m) differential feeding antenna elements. Each differential feeding antenna element is a differential feeding structure with a microstrip antenna stripe. The stripe length is shorter than one wavelength to minimise the antenna area and to prevent being excited to a high-order mode. That is, the differential feeding antenna element can suppress the even mode. The mutual coupling between the antenna elements can be suppressed, and the isolation between the receiver and the transmitter can be enhanced. An inclination angle of the main beam aligns with the broadside, and the main beam is further concentrated and shrunk at the elevation direction. Moreover, if more differential feeding antenna elements are used, antenna gain and isolation can be further enhanced. The excellent performance of the proposed antenna arrays indicates that they are suitable for both MWPT systems and dual-antenna transceivers. 相似文献
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《Microwave Theory and Techniques》1981,29(9):967-970
A new circularly polarized antenna using a dielectric image line is proposed. This antenna is composed of a slotted conductive plane and a rectangular dielectric rod. This paper describes the design of and experimental results achieved with the circularly polarized array antenna fed by a dielectric image line. The fundemental characteristics of the image line are also presented. Since this line's losses are far lower than the microstrip line losses in the millimeter wavebands, antenna feed line losses expect to be also very low. Bandwidth within the 2-dB axial ratio was more than 7 percent, and the angle range within the same ratio was more than +-7.8 degrees at 29.5 GHz. This antenna is far superior to the microstrip line feed array antenna in the millimeter wavebands. 相似文献
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A satellite borne synthetic aperture radar can image a wide swath in the order of 700 km with one-look 100-m resolution. If the design meets the ambiguity constraints at the far edge of the swath, the maximum swath width is independent of both radar wavelength and shape of the physical antenna aperture. The antenna pattern can be a pencil beam scanned in the elevation plane, or a fan beam formed by a long antenna. The scanning pencil beam antenna may be a phased array or multiple-feed reflector which may be more practical than a long antenna to image a wide swath. Design performance trade computations are presented involving resolution, swath width, antenna area, average transmitter power and digital data rate. 相似文献
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Characteristics of a Metal-Backed Loop Antenna and its Application to a High-Frequency RFID Smart Shelf 总被引:1,自引:0,他引:1
Xianming Qing Zhi Ning Chen 《Antennas and Propagation Magazine, IEEE》2009,51(2):26-38
In this paper, a metal-backed loop antenna (MBLA) at high frequency (HF) is characterized and applied to a radio-frequency identification (RFID) smart-shelf system. The antenna is investigated in terms of impedance matching, resonant frequency, magnetic-field intensity/field distribution, quality factor, and detection range. The study shows that the magnetic-field distribution of the metal-backed loop antenna can be effectively controlled by changing the size as well as the separation of the backing metal plate. As a result, the detection range of an RFID system using such an antenna can be controlled. Such a feature offers great promise for the metal-backed loop antenna in applications for RFID smart-shelf systems. For such systems, controlling the coupling zone of the antennas is vital for constraining the interference between the antennas in adjacent tiers of the shelves, in order to achieve high system-detection accuracy. In addition, using a metal-backed loop antenna provides more flexibility for RFID smart-shelf-system design and implementation, so that the system is more cost effective. 相似文献
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A novel miniature planar inverted-F antenna (PIFA) design without empty space is presented for 2.4 GHz ISM band applications. The antenna fabricated on an FR4 substrate has an overall size of only 10 (L) x 3 (W) x 3.5 (H) mm3 to be embedded inside the portable devices. By properly adding a shorting pin and etching a bent slot, the operating frequency of the antenna can be lowered more flexibly. Moreover, owing to no additional empty space, the circuit routing on the PCB is permitted underneath and around the antenna. The impedance bandwidth of the antenna is about 160 MHz from 2.39 to 2.55 GHz. Good omnidirectional radiation pattern with appreciable gain across the band can be obtained so that the proposed antenna is suitable for Bluetooth and WLAN applications. 相似文献
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Electromagnetic band-gap (EBG) structures have unique properties in controlling the propagation of electromagnetic wave and
have been applied to a wide range of electromagnetic devices design. In this paper, a double-sided printed dipole (DSPD) array
backed by an EBG reflector is proposed for achieving a low-profile design as well as gain enhancement. Simulation results
show that a reduction of more than 55% in antenna height can be obtained by placing the DSPD array over an EBG reflector rather
than a perfect electric conductor (PEC) reflector. And the obtained gain of the antenna with an EBG reflector is about 1.9 dB
higher than that with a PEC reflector at the operating frequency 2.77 GHz. The EBG reflector can be utilized to reduce a cavity-backed
antenna height and enhance the antenna radiation efficiency. The design has a good potential application to antenna arrays
with more elements in wireless communication. 相似文献
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Xiaofeng Lu Fletcher D. Wicker Don Towsley Zhang Xiong Pietro Lio’ 《Wireless Personal Communications》2010,55(1):51-63
This paper studies the problem of detection of directional antennas and omni-directional antennas by hostile detection systems.
We present a model for calculating the probability of detecting a transmitter at arbitrary location around the transmitter.
Our study shows that, if a directional antenna employs the same transmit power as an omni-directional antenna, the directional
antenna can not decrease the probability of being detected. In some scenarios, a directional antenna is more likely to be
detected than an omni-directional antenna. However, if a directional antenna provides the same Effective Isotropic Radiated
Power in the direction of the receiver as an omni-directional antenna, the transmit power needed by a directional antenna
to send data is much less than that of an omni-directional antenna. In this scenario, the probability of detecting a directional
antenna is reduced by over 90%. This reveals that directional antennas can be used to build a secure path to send data at
low probability of being detected by adversaries. 相似文献
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Naser Ojaroudi Parchin 《Wireless Personal Communications》2017,97(3):3293-3300
In this study, a novel design of insensitive antenna with improved radiation performance is designed and investigated. The antenna exhibits excellent performance in terms of impedance-matching, radiation and total efficiencies, even though it is designed and fabricated using high loss substrate (FR) with compact dimension. An L-shaped metal-ring resonator has been used as a main resonator of the antenna to operate at 18.5 GHz. In order to improve the antenna performance, a part of substrate with L-shaped configuration has been removed and a metal ring structure is inserted. By using this technique, we can improve the efficiency characteristic of the antenna and eliminate the effect of high-loss FR-4 substrate. The center frequency of the designed antenna can be controlled by adjusting the values of the antenna parameters. Since the main substrate of the resonator is the air, the antenna is insensitive for different types of antenna substrates. It has the return loss characteristic less than ?10 dB in the frequency range of 17.5–19.5 GHz (more than 10% fractional bandwidth). The antenna has a very compact size with good radiation behavior and could be used in phased array antennas for next generation systems. 相似文献
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Low Profile GALILEO Antenna Using EBG Technology 总被引:1,自引:0,他引:1
Baggen R. Martinez-Vazquez M. Leiss J. Holzwarth S. Drioli L.S. de Maagt P. 《Antennas and Propagation, IEEE Transactions on》2008,56(3):667-674
A dedicated low profile antenna for geodesic applications is presented. This type of antenna requires mitigation of multipath signals to achieve sub-centimeter level of precision. Typically, bulky and heavy choke ring structures have been used to reduce the effects of multipath interference. The antenna presented here consists of a low temperature co-fired ceramic (LTCC) patch antenna immersed in an electromagnetic bandgap (EBG) substrate. The EBG substrate reduces the effects of multipath by blocking the propagation of surface waves. The result is an antenna showing good multipath rejection and a stable phase center. The advantage of printed EBG substrates is that they can be realized in a low-weight, low-price, and low-profile fashion. First prototypes have been manufactured and tested, and its performance has been compared to that of a more classical choke ring antenna. 相似文献
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针对现有及未来5G移动通信天线空间辐射特性测试需求和特点,设计了一套分布式天线远场三维测试系统,集成于高性能微波暗室内。发射天线采用多工位设计,高效率地实现了远程无人值守测试。基于U型测试转台实现了待测天线的三维方向图一键测试,具备双测试通路多频点多端口测试功能,有效提高了天线测试效率。系统软件具有较强后处理能力,将测试理论知识有效地应用于工程实践,如软件时域门和远场修正技术等,可获取更为精确的测试结果。以运营商提供的定向基站天线作为系统性能验证鉴定天线,通过与其在其它优良测试远场获取的测试数据进行对比。结果表明,本系统能够较好地满足运营商对目前移动通信天线测试场地及设备的测试要求,具备一键测试、多功能、宽频带、高精度、高效率等特点,易于拓展具备5G移动通信天线空间辐射特性的测试功能。 相似文献
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为了解决车载通信天线工作频带窄、尺寸大等缺点,文中提出了一款应用于车载鲨鱼鳍外壳的新型小型化、宽带MIMO天线。为了实现天线的宽带特性,充分利用了印制单极子天线易于引入多谐振的特点,首先通过合理的尺寸设计,将单极子天线谐振频率设计至工作频段中;然后,使用缝隙加载技术,增加天线谐振模式数量并改善天线阻抗匹配特性,拓宽了天线带宽并实现了天线的小型化。为了验证天线实际性能,将天线安装于鲨鱼鳍外壳中进行了测试。结果表明,该天线可以覆盖824~5 000 MHz的频段范围,驻波比均小于3,增益最低1.9 d Bi、最高6.2 d B,效率均高于49.5%、最高达89.2%。该天线可满足车载通信系统对天线的宽带化和小型化要求。 相似文献