Current Issue : January - March Volume : 2016 Issue Number : 1 Articles : 7 Articles
Full dimension MIMO (FD-MIMO) is one of the key technologies presently studied in the 3GPP for the next generation long-term\nevolution advanced (LTE-A) systems. By incorporating FD-MIMO into LTE/LTE-A systems, it is expected that system throughput\nwill be drastically improved beyond what is possible in conventional LTE systems. This paper pre sets details on the 2D active\nantenna array design for FD-MIMO systems supporting 32 antenna elements. The FD-MIMO system allows for dynamic and\nadaptive precoding to be performed jointly across all antennas thus achieving more directional transmissions in the azimuth and\nelevation domains simultaneously, to a larger number of users. Finally, we discuss 2D antenna array port virtualization techniques\nfor creating beams with wide coverage, necessary for broadcasting signals to all users within a sector, such as the CRS (Common\nReference Signal)....
This paper presents a long-term evolution (LTE) 700MHz band multiple-input-multiple-output (MIMO) antenna, and high\nisolation between the two symmetrical antenna elements is obtained without introducing extra decoupling structure. Each antenna\nelement is a combination antenna of PIFA and a meander monopole antenna. The end of the PIFA and the meander monopole\nantenna are, respectively, overlapped with the 50Ã?© microstrip feed line, the two overlapping areas produce additional capacitance\nwhich can be considered decoupling structures to enhance the isolation for the MIMO antenna, as well as the impedance matching\nof the antenna elements. The MIMO antenna is etched on FR4 PCB board with dimensions of 71 Ã?â?? 40 Ã?â?? 1.6mm3; the edge-to-edge\nseparation of the two antenna elements is only nearly 0.037 ...
A novel cavity-backed probe-fed linearly polarized microstrip antenna based on the concept of hybrid radiators is proposed and\nimplemented. The resulting flush-mounted antenna exhibits symmetrical bandwidth, low cross-polarization radiation in the Hplane,\ndue to its hybrid patch, and low cost, since it can be built on a FR4 laminate. Substrate integrated waveguide technology is\nused in the fabrication of the metallic cavity.The effect of mutual coupling is analyzed for two classical arrangements: the side-byside\nand the collinear configurations....
Wave propagation along a closely spaced folded cylindrical helix (FCH) array is investigated for the purpose of designing compact\narray for energy transport and antenna radiation. It is found that the height of this surface wave guiding structure can be decreased\nfrom 0.24...
Approximate formulas are obtained for the electromagnetic pulses due to a delta-function current in a vertical electric dipole on\nthe planar surface of a perfect conductor coated by a dielectric layer. The new approximated formulas for the electromagnetic field\nin time domain are retreated analytically and some new results are obtained. Computations and discussions are carried out for\nthe time-domain field components radiated by a vertical electric dipole in the presence of three-layered region. It is shown that the\ntrapped-surface-wave terms should be included in the total transient field when both the vertical electric dipole and the observation\npoint are on or near the planar surface of the dielectric-coated earth....
This paper presents some key considerations for modeling of over-sea radio-wave propagations in 5GHz band. The summarized\ninformation is based on a series of measurement campaigns which were recently carried out in the tropical maritime environments\nnear Singapore. Multiray propagations and ducting of radio waves have been highlighted and considered in over-sea path loss\nmodeling and prediction. It is noted that the sea-surface reflection is an important contribution in the received field, while the duct\nlayers could enhance the radio-wave propagations. Our studies also show that the refracted ray inside evaporation duct could be a\nstrong ray for short-range near sea-surface applications and needs to be properly evaluated....
This paper addresses the problem of designing shaped beam patterns with arbitrary arrays subject to constraints. The constraints\ncould include the sidelobe level suppression in specified angular intervals, the mainlobe half power beamwidth, and the predefined\nnumber of elements. In this paper, we propose a new Differential Evolution algorithm, which combines Composite DE with an\neigenvector-based crossover operator (CODE-EIG). This operator utilizes eigenvectors of covariance matrix of individual solutions,\nwhich makes the crossover rotationally invariant. We apply this novel design method to shaped beam pattern synthesis for linear\nand conformal arrays. We compare this algorithm with other popular algorithms and DE variants. The results show CODE-EIG\noutperforms the other DE algorithms in terms of statistical results and convergence speed....
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