共查询到20条相似文献,搜索用时 31 毫秒
1.
A compact planar inverted-L diversity antenna for handheld terminals is presented. Three diversity antennas operating at 2.15GHz are designed. The isolation is found to be higher than 13 dB and the usable bandwidth is about 13% in measurement. The measured radiation patterns of the proposed diversity antenna attain 2 dBi gain. Furthermore, the diversity performance with mean effective gain (MEG) is evaluated by taking both azimuth and elevation spectrum into account. A closed-form expression for MEG is presented. The effect of some parameters on MEG is analyzed numerically in indoor propagation environments. 相似文献
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A Novel Dual-Band Printed Diversity Antenna for Mobile Terminals 总被引:3,自引:0,他引:3
Yuan Ding Zhengwei Du Ke Gong Zhenghe Feng 《Antennas and Propagation, IEEE Transactions on》2007,55(7):2088-2096
A novel dual-band printed diversity antenna is proposed and studied. The antenna, which consists of two back-to- back monopoles with symmetric configuration, is printed on a printed circuit board. The effects of some important parameters of the proposed antenna are deeply studied and the design methodology is given. A prototype of the proposed antenna operating at UMTS (1920-2170 MHz) and 2.4-GHz WLAN (2400-2484 MHz) bands is provided to demonstrate the usability of the methodology in dual-band diversity antenna for mobile terminals. In the above two bands, the isolations of the prototype are larger than 13 dB and 16 dB, respectively. The measured radiation patterns of the two monopoles in general cover complementary space regions. The diversity performance is also evaluated by calculating the envelope correlation coefficient, the mean effective gains of the antenna elements and the diversity gain. It is proved that the proposed antenna can provide spatial and pattern diversity to combat multipath fading. 相似文献
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A dual-wideband fractal monopole antenna for handheld terminals is proposed. A modified half-Sierpinski gasket patch is used to cover GPS, DCS1800, PCS1800, UMTS, IMT-2000, WiBro (Wireless Broadband Internet Service), Bluetooth, S-DMB (Satellite Digital Multimedia Broadcast) and WLAN bands. The proposed antenna exhibits two wideband frequency resonances. The measured -10-dB reflection bandwidths for two resonant frequencies are 55- (1517-2670-MHz) and 12.6- (5135-5828-MHz). The radiation characteristics and gain of the proposed antenna are also presented and discussed. 相似文献
4.
A new printed structure composed of a dipole and a loop antenna for achieving a unidirectional antenna is proposed. The proposed antenna demonstrates that when an electric dipole and a magnetic dipole are excited simultaneously, a unidirectional radiation pattern can be obtained. With the absence of any ground plane or reflector, this directional printed antenna with single-layer structure can be used nowadays in small directional wireless systems and some handheld devices that need to radiate in a particular direction. The antenna operates at 2.4 GHz with an impedance bandwidth of 7.4% for S11 < -10 dB and a peak measured gain of around 4.3 dBi. 相似文献
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In this paper, a two-element UWB MIMO antenna with bi-directional radiation pattern is designed for superior UWB MIMO performance. The designed antenna adopts asymmetric coplanar waveguide ground feeding. The proposed antenna ECC is lower than the ECC of its omni-directional peer antenna. Simulated and measured ECC is lower than 0.016 over the entire ultra-wide bandwidth (3.1–10.6 GHz). The isolation between elements of the designed antenna is 20–25 dB exceeding the average in recently published works. The designed antenna has a diversity gain of almost 10 dB and average multiplexing efficiency of 85% over the entire ultra-wide bandwidth. The antenna preserves radiation efficiency higher than 0.96 and gain 3 dB. The diversity performance of the proposed UWB MIMO antenna is proven through real rich-multipath indoor environment measurements. Stationarity of the elected channel is evaluated through 100 successive measurements separated by a 3-min period for 5 h long. The measured spatial correlation coefficients are much lower than 0.5 in different scenarios. 相似文献
6.
Modified meander line monopole antenna for broadband operation 总被引:2,自引:0,他引:2
A modified meander line monopole antenna is presented for broadband operation. The impedance and radiation characteristics of the antenna are investigated. The proposed antenna achieved a bandwidth of approximately 845 MHz with S11< -10 dB, which covered the GPS, DCS, PCS, UMTS and WiBro bands. The electrical characteristics of the proposed antenna appear to be attractive for mobile terminals and repeater applications. 相似文献
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Antenna-gain measurement of handheld terminals at 900 MHz 总被引:1,自引:0,他引:1
This paper presents antenna-gain measurements of handheld terminals by the random-field measurement (RFM) method. We have measured the relative antenna gain for different-sized terminal boxes in indoor and outdoor environments to show a gain decrease caused by the box size. The measured results are explained by calculating the average gain of the horizontal radiation pattern. To find the effect by a different human carrier, we also measured the antenna gain for several parameters, such as weight, height, head parameters, and the antenna protruding length from the head. We present a correlation factor of the antenna-gain deviation due to different human carriers 相似文献
9.
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
10.
A novel shorted dual spiral printed antenna is presented. The antenna consists of two interleaved shorted spiral radiators and a feed network etched on a high dielectric material below the ground plane. A 10 dB return loss bandwidth of 9.2% has been achieved with an omni-directional radiation pattern. The proposed antenna is 28% smaller than a conventional shorted patch antenna, making it very desirable for mobile communication handset terminals 相似文献
11.
Yong-Woong Jang 《Microwave and Wireless Components Letters, IEEE》2001,11(10):425-427
The proposed novel three-offset shaped microstripline-fed slot antenna has a radiation pattern similar to the conventional microstrip slot antenna and the advantage of more bandwidth. The measured bandwidth is approximately 1.796 octave (VSWR⩽2.0), Experimental results for the impedance loci and the radiation patterns are also presented 相似文献
12.
Yuehui Ouyang Love D.J. Chappell W.J. 《Vehicular Technology, IEEE Transactions on》2009,58(4):1752-1765
In this paper, we analyze the performance of novel wearable multiple-input-multiple-output (MIMO) systems, which consist of multiple electrotextile wearable antennas distributed at different locations on human clothing. For wearable applications, a semidirectional radiation pattern of the wearable patch antenna is preferred over an omnidirectional radiation of conventional dipole antennas to avoid unnecessary radiation exposure to the human body and radiation losses. Additionally, the spatial distribution of the antennas is not constrained as a typical handheld unit. Through theoretical modeling and simulation, the wearable MIMO system is shown to demonstrate a significantly higher channel capacity than a conventional system on a handheld platform (e.g., a compact dipole array or a single dipole), due to enhanced spatial diversity and antenna pattern diversity. The unique effects of antenna directivity and location on the MIMO system capacity are investigated in terms of antenna correlation and effective gain under different wireless channel models. The advantage of a wearable system over a conventional system was further confirmed by detailed physical modeling through the combination of full-wave electromagnetic and ray-tracing simulations. Finally, complex channel response matrices were measured to characterize the performance of a body-worn MIMO system in comparison with a reference full-size dipole antenna. The 319% improvement in 10% outage capacity for the body-worn system over the reference system made of a full-size dipole antenna is consistent with the 288% improvement projected by theoretical modeling and the average 300% improvement found in the physical simulation of two typical indoor scenarios. 相似文献
13.
Smart antennas in wireless communications: base-station diversity and handset beamforming 总被引:1,自引:0,他引:1
Dietrich C.B. Jr. Stutzman W.L. Byung-Ki Kim Dietze K. 《Antennas and Propagation Magazine, IEEE》2000,42(5):142-151
We review diversity and smart antenna research applied to both base-stations and terminals. To illustrate the performance gains possible, the paper describes research being conducted by the Smart Antenna Group at Virginia Tech, in both smart base-stations and smart handheld terminals. 相似文献
14.
CPW-fed ultra-wideband antenna with compact size 总被引:1,自引:0,他引:1
A coplanar waveguide (CPW)-fed ultra-wideband (UWB) antenna with compact size is presented. The entire size of the antenna is as small as 30times13times1.6timesmm. The measured and simulated impedance bandwidth defined by voltage-standing wave ratios <2 is from 3.1 to more than 10.6 GHz. The proposed antenna exhibits a nearly omni-directional radiation pattern with very compact size, which is suitable for various portable UWB systems. 相似文献
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该文设计了一种新颖的宽带圆极化单极子天线,该天线采用微带馈电模式。天线由C型贴片和改进的地板组成,整个天线尺寸仅为25×25×1 mm3。通过在C型贴片上切角和在地板上增加三角形微扰结构,可以有效增加天线的阻抗带宽和轴比带宽。该文给出了天线的设计流程,从表面电流分布分析了圆极化天线的工作机理。加工了天线实物,并对其进行了测量。仿真和实测结果表明天线具有超宽的阻抗带宽和轴比带宽。天线的工作频带为4.35~12 GHz(相对带宽为93.6%),3 dB轴比带宽为4.15~11.8 GHz(相对带宽为95.9%)。测量了天线的辐射性能和增益特性,实测结果与仿真结果吻合较好,证明了该天线的有效性。该天线可以应用于超宽带无线通信系统和卫星通信系统中。 相似文献
17.
Reduction in antenna size by using multi-band radiators play a vital role in the miniaturization of present world wireless handheld devices, as dual band behaviour of the antennas result in the integration of more than one communication standard in a single system and thus, saving the installation space required for separate antennas. In this context, this communication presents a shorted-pin dual band metamaterial inspired microstrip patch antenna array. Under the unloaded conditions, the traditional patch antenna array resonates at 5.8 GHz with gain of 9.8 dBi and bandwidth of 540 MHz. However, when each patch of this traditional antenna array is loaded with split ring resonator (SRR) and a metallic via hole is introduced in the patch, the same antenna array produces an additional resonant frequency in IEEE 802.11b/g/n 2.45 GHz Wi-Fi band with bandwidth and gain of 290 MHz and 5.6 dBi, respectively, while the initial resonant frequency (i.e. 5.8 GHz) gets shifted to IEEE 802.11ac 5 GHz Wi-Fi band, providing the gain and bandwidth of 11.4 dBi and 510 MHz, respectively. The proposed antenna array has been fabricated, and the measured results are presented to validate the proposed array. Moreover, the equivalent circuit of the proposed antenna array has been designed and analyzed to validate the simulated, measured and theoretical results. Attainment of dual band characteristics by incorporating the metamaterial with single band traditional patch antenna array makes this structure novel, as this has been achieved without any extra hardware cost, size and loss of structural planarity. Also, both the frequency bands of this proposed metamaterial inspired antenna array possess considerable gain and bandwidth. 相似文献
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A modified helix chip antenna is presented for WiBro and WLAN applications. The impedance and radiation characteristics of the antenna are investigated. The antenna is formed on both sides of the substrate (3.5 times 8 times 0.8 mm, FR4). The measured results show that the proposed antenna has a bandwidth of 290 MHz (2.26-2.55 GHz) and a maximum radiation gain of 1.468 dBi. 相似文献