共查询到20条相似文献,搜索用时 453 毫秒
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一种应用于微蜂窝基站的覆盖5个频段的新型多频段小型化内置天线被提出。该天线的体积为26×16×25mm3,可以工作于以下无线通信系统:GSM850/GSM900/DCS/PCS/UMTS。将该天线与微蜂窝基站模型安装在一起之后的测试结果和仿真结果都已给出并予以讨论。 相似文献
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Kumaran Natesan Ramesh Subramaniam Chitra Sivathanu 《International Journal of Communication Systems》2023,36(14):e5551
A reconfigurable MIMO antenna for heterogeneous vehicular networks is reported in this paper. The frequency and bandwidth characteristics of the MIMO antenna can be reconfigured to meet multi-standard and multi-frequency requirements in automobiles. The antenna element evolved from an edge-chamfered ultra-wideband (UWB) antenna operating from 2.1 to >15 GHz. The bandwidth reconfiguration is achieved through the selection of excitation paths connecting the feed and radiator. The feedline selection is performed using PIN diodes, making the antenna operate in three distinct modes, namely, UWB mode (Mode 1: 2.1–>15 GHz), industrial, scientific and medical/Internet of Things (ISM/IoT) mode (Mode 2: 2.45 GHz), and wireless local area network (WLAN) mode (Mode 3: 5–6 GHz). The feed path corresponding to Mode 2 and Mode 3 is incorporated with a suitable filtering network to shape the frequency response of the antenna based on the user's requirements. Owing to the requirement of cognitive selection of frequency bands, the frequency tunability in Mode 2 is realized using varactor diodes. The varactor-incorporated feed path reconfigures the center frequency between 2.45 and 3.5 GHz. The proposed MIMO antenna offers gain and total efficiency greater than 2.94 dBi and 76%, respectively. The prototype of the 4-port MIMO antenna is being fabricated to test its functionality in real time. 相似文献
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本文设计出了一种既能产生针状波束又能产生扇形波束的新型面天线,该天线的增益和方向图通过理论计算计算出来。本文设计实例中的面天线的针状波束的E、H平面的半功率宽度分别为2.320、2.240,而扇形波束的E、H平面的半功率宽度分别为2.010,6.40。 相似文献
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通过数值计算发现 ,在垂直于天线对称轴的平面内向天线对称轴平移抛物面的两个精心选定的对称部分后 ,赋形抛物面天线可产生扇形波束。馈源方向图为cosθ、抛物面口径半径为 0 .8m的抛物面经赋形后E、H平面的半功率宽度分别可达到 5.3 6°、0 .90° ,而E、H平面的副瓣电平分别为 -6.84dB、-7.86dB。 相似文献
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Sandra Costanzo Ignazio Venneri Giuseppe Di Massa 《Journal of Infrared, Millimeter and Terahertz Waves》2009,30(4):374-380
The use of circular waveguide radiators electromagnetically coupled to a stripline distribution network is proposed in this
work as wideband hybrid array configuration suitable for millimeter-wave applications. The adopted excitation mechanism avoids
the use of transition components from stripline to radiators, which are responsible for loss mechanisms affecting similar
configurations in literature. The effectiveness of the hybrid approach is first validated on a reduced frequency X-band prototype.
Then, a Ka-band array design is presented and experimentally tested to prove the wideband radiation behavior. A radiation
efficiency of about 60 percent is also demonstrated on the Ka-band prototype. 相似文献
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In this study, a quad-port multi-polarized ultra-wideband (UWB) multiple input multiple output (MIMO) antenna system with a new isolation technique is designed for wireless devices. The antenna structure consists of four triangular monopole elements and neutralization ring (NR) structures. The monopoles are back-to-back positioned in symmetrical and orthogonal arrangement. Therefore, they radiate towards four directions without interference, and thus the diversity performance is improved. A novel NR is formed by combining a rectangular ring and a straight line to reduce the mutual coupling due to interoperation of the elements. Each triangular monopole is fed by 50 Ohm microstrip transmission line (MTL) with a thin strip line for ensuring impedance matching. Antenna performance in terms of impedance bandwidth, current distribution, radiation pattern, peak gain and envelope correlation coefficient (ECC) is also investigated. The MIMO antenna system has 3.1–17.3 GHz impedance bandwidth, 1–5 dBi peak gain variation, less than 0.1 ECC. The results indicate that the proposed antenna has the characteristics of larger UWB bandwidth, high isolation by the NR structure, multi-polarization, uniform gain and quasi-omnidirectional pattern. 相似文献
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Melad M. Olaimat 《International Journal of Electronics》2013,100(3):407-424
In this article, an improved formula for the effective side length (a eff) of the equilateral triangular patch antenna is presented. The computed resonant frequencies for the first five modes, using this formula, are compared with the available experimental and theoretical results in the literature. It is shown that the proposed formula has better accuracy than other available expressions. Moreover, the 30°–60°–90° and 30°–30°–120° triangular patch antennas are studied. Specifically, improved formulae for the effective dielectric constant of these patches are derived. 相似文献
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V.A. ShameenaS. Mridula Anju PradeepSarah Jacob A.O. LindoP. Mohanan 《AEUE-International Journal of Electronics and Communications》2012,66(3):189-194
A printed compact coplanar waveguide fed triangular slot antenna for ultra wide band (UWB) communication systems is presented. The antenna comprises of a triangular slot loaded ground plane with a T shaped strip radiator to enhance the bandwidth and radiation. This compact antenna has a dimension of 26 mm × 26 mm when printed on a substrate of dielectric constant 4.4 and thickness 1.6 mm. Design equations are implemented and validated for different substrates. The pulse distortion is insignificant and is verified by the measured antenna performance with high signal fidelity and virtually steady group delay. The simulation and experiment reveal that the proposed antenna exhibits good impedance match, stable radiation patterns and constant gain and group delay over the entire operating band. 相似文献
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Yatendra Kumar Ravi Kumar Gangwar Binod Kumar Kanaujia 《International Journal of Electronics》2020,107(4):596-612
ABSTRACTIn this article, asymmetrical mirror-imaged monopole antenna comprises a rectangular patch with tuneable stub and supported with modified ground structure (MGS) is investigated. The proposed antenna is characterised for dual band dual polarised (DBDP) radiations and can operate at 2.45 GHz for Wi-Fi and WLAN systems (2.4–2.485 GHz) and 5.45 GHz for WLAN band (WLAN band: 5.2–5.8 GHz) with the corresponding polarisations. A rectangular patch integrated with tuneable stub and a pair of asymmetrical inverted L-shaped slots positioned at ground plane is responsible for circularly polarised higher band; while a parasitic patch is created due to slotting of a mirror-imaged stub from the extended ground plane which is accountable for lower frequency band. The fabricated prototype shows that the measured Impedance bandwidths (VSWR < 2) are 350 and 1770 MHz for lower and higher frequency bands, respectively. The measured axial ratio bandwidth (AR < 3 dB) is yielded as 1450 MHz centred at 5.44 GHz for higher frequency band. The peak gains are measured as 4.3 and 4.15 dB for lower and higher frequency band, respectively. For the prototype antenna, substantial 3-dB beamwidth is found along with good cross polarisation suppression. 相似文献
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K. Siakavara 《International Journal of Electronics》2013,100(3):277-283
The multi-band frequency operation is a property that antennas, utilized in several communication systems, have to exhibit. In this paper, a compact printed antenna for Global Positioning System (GPS) and terrestrial radio services is presented. It is composed via the union of four inverse Koch fractal patches. The antenna operates in three frequency ranges (GPS, Digital Cellular System-DCS1800 and 2.7?GHz). It is driven by two feed probes, directly matched to the radiating element without any matching network to be necessary. At GPS, the antenna is capable of generating a circularly polarized field, with maximum strength at the broadside direction. At the other two frequencies, the field is linearly polarized and the maximum of radiation appears apart from the broadside. Two pins, embedded in the structure, are activated at DCS and at 2.7?GHz in order to enhance the performance of the antenna. 相似文献