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The authors introduce a multistate phase diversity scheme to reduce fading problems at the base station end in a microcellular environment. The results obtained show that the phase diversity scheme provides a considerable improvement at the receiving end with a compact antenna configuration 相似文献
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The broadband design of a circular array of bent stacked slot antennas (BSSAs) is presented. The angular diversity provided can mitigate multipath propagation and intersymbol interference occurring in indoor wireless communications. Details of the antenna design and experimental results are presented for a fixed sector configuration at 5.2 GHz. Numerical simulation results are consistent with experiments. The 3 dB beamwidth in azimuth and elevation is ~75 and 50°, respectively, and the directivity is 7.7 dBi. Over the whole HIPERLAN bandwidth, a -18 dB return loss is achieved, with only a 3 dB degradation of secondary radiation lobes 相似文献
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Tanaka S. Harada A. Sawahashi M. Adachi F. 《Selected Areas in Communications, IEEE Journal on》2000,18(8):1495-1504
In wideband direct sequence code division multiple access (W-CDMA), employing an adaptive antenna array is a very promising technique to reduce severe multiple access interference (MAI) from high rate users. A four-antenna pilot symbol-assisted coherent adaptive antenna array diversity (PSA-CAAAD) receiver comprising an adaptive antenna array based on a minimum mean squared error (MMSE) criterion and a RAKE combiner is implemented in preliminary laboratory and field experiments. There are two important design concepts of the PSA-CAAAD receiver. The first is that the adaptive antenna array forms an antenna beam for each resolved propagation path and tracks only slow changes in the directions of arrival (DOAs) and average powers of the desired and interfering user signals. The second is that the RAKE combiner tracks the instantaneous changes in channel conditions and coherently combines the signals of the desired user propagating along the resolved paths to maximize the instantaneous signal-to-interference plus background noise power ratio (SINR). This paper presents, both by laboratory and field experiments, the effectiveness of PSA-CAAAD receiver as a powerful means to reduce severe MAI from high rate users, and that it is more effective than using a space diversity receiver with the same number of antennas in the W-CDMA reverse link 相似文献
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An analytical approach to the design of a super-synthesis antenna array is applied in this paper. It involves isolation and separate optimization of the influence of different parameters on the sampling of the spatial frequency components. The approach requires a detailed understanding of the geometry of tracking by an ensemble of baselines, but it gives a nearly optimum array design without much help from a computer. A feature of this design is that by simply doubling the array elements, the synthesized main beam area of the array is reduced 16 fold. Extensive computations have been used to demonstrate this extraordinary result. 相似文献
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A set of arbitrarily located receiving antenna elements, each connected with an appropriate network, can be used to construct a matched filter where the antenna array response results in an autocorrelation of a specified desired signal, correlating over time and space coordinates simultaneously. A receiving system using such a signal processing antenna can discard interferences which do not have the same spectral characteristics as the desired signal, or which do not originate from the same point as the desired signal source. Examples of correlating antenna arrays for various arbitrary intelligence modulations of the desired signal are discussed in this communication. 相似文献
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基于AD8302的甚高频天线阵电缆相位差检测 总被引:1,自引:0,他引:1
《现代电子技术》2017,(9):104-107
根据甚高频天线阵相位测量原理,提出一种利用相位检测芯片AD8302将接收机至传输馈线的两两阵元的定标信源信号的相位差转化为对应的直流电压,再用12 b量化精度单通道A/D采样,最后做误差分析及修正达到修正相位误差的方法。通过验证在低频(2 MHz等)、高频(300 MHz等)等测量条件下,系统给出的电缆相位误差的精度,如在300 MHz信号输入下,电缆之间距离误差达到了cm精度,可以广泛用于相关天线阵误差修正及电缆误差测量中。 相似文献
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L. G. Kornienko 《Radioelectronics and Communications Systems》2010,53(4):185-194
Polarization properties of the field of linear antenna arrays with random phase errors in the excitation currents of orthogonal
vibrators and a system of biorthogonal radiators are studied. The influence of errors’ correlation on the degree of polarization
and ellipticity of antenna with broadside radiation of waves with circular polarization is analyzed. 相似文献
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Bui L.A. Mitchell A. Ghorbani K. Tan-Huat Chio Mansoori S. Lopez E.R. 《Antennas and Propagation, IEEE Transactions on》2005,53(11):3589-3596
In this paper, a wide-band photonically phased array antenna is demonstrated. The array configuration consists of a 4 /spl times/ 1 Vivaldi single-polarization antenna array and an independent photonic phasing system for each element. The phasing network of this array is implemented using two novel photonic phase shifters based on the vector summation approach. A vector sum phase shifter (VSPS), which exhibits a frequency-linear characteristic from dc to 15 GHz and can be continuously tuned from 0 to 100/spl deg/, is presented. A second-order VSPS (SO-VSPS), a modification of the VSPS that is capable of 0-430/spl deg/ phasing range, is also demonstrated. This paper presents the operation and characterization of each component of the array, including the radiating elements and the various photonic phase shifters and, finally, a demonstration of the combined system. A discussion on the practicality of this system for airborne applications is presented, along with suggestions for simplification and improvement. 相似文献
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数字阵列天线测量方法研究 总被引:1,自引:0,他引:1
提出了数字阵列天线应测量的技术指标体系。基于数字阵列天线各通道的幅度相位可控,推导出了数字阵列天线方向图的中场测量公式。在已知数字阵列TR组件接收电路增益的基础上,给出了数字阵列天线接收增益测量方法。为避免分别测量数字阵列天线的有源电压驻波比和发射增益,给出了等效全向辐射功率的测量方法。实验结果验证了数字阵列天线方向图和接收增益测量方法的正确性。 相似文献
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The shape of the beam of a spherical random antenna array is discussed and the main parameters, such as bandwidth, beamwidth and hyperfocal distance are determined. 相似文献
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Tae-Yeoul Yun Kai Chang 《Antennas and Propagation, IEEE Transactions on》2001,49(9):1290-1298
A new phased array antenna of wide bandwidth and good beam scanning angle has been developed using a low cost multiline phase shifter controlled by a piezoelectric transducer (PET) and a stripline fed Vivaldi antenna array. The multiline progressive PET phase shifter has a low perturbation loss of less than 2 dB and a total loss of less than 4 dB up to 40 GHz with a maximum phase shift of 480°. The proposed phased array antenna consists of four E- or H-plane Vivaldi antennas, a PET phase shifter, and a power divider. The phased array shows a wide beam scanning capability of ±27° over a wide bandwidth from 8 to 26.5 GHz covering X, Ku, and K bands 相似文献
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A microstrip array with mutual coupled rectangular patch radiators is described. By the avoidance of a corporate feeding network, advantages in the antenna performance and design are realisable. Experimental results are presented for both linearly and circularly polarised antennas which demonstrate the usefulness of this special antenna configuration. 相似文献
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A planar adaptive array of three microstrip patch antennas consisting of a central active microstrip antenna and two symmetrical lateral passive antennas is used to steer the beam. An electronic beam scanning of ±20° can be achieved with the control of reactive loads located into the lateral patches 相似文献
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A microstrip-fed crossed-slot array antenna having a circular polarisation is developed. First, a single crossed-slot antenna, that can radiate a circularly polarised wave in the broadside direction, is designed and its coupling level to the microstrip line is analysed. Based on this result, an eight-element crossed-slot array is designed and its characteristics are experimentally investigated at 12 GHz band. The return loss of -17 dB is obtained at the design frequency of 11.85 GHz, and the axial ratio of less than 3 dB is achieved over the fractional bandwidth of 5%. 相似文献