NCG7000 vaguely resembles the outline of the North American continent. (Deneb, Vega and Altair make up the Summer Triangle). Cygnus is sometimes called the Northern Cross and has the very bright star Deneb as the head of the cross. North American Nebula (NGC7000): A hydrogen and dust cloud located in the constellation Cygnus which you can see rising in the east in summer to fall. The simulation results of this paper will give contribution to the super-resolution focusing for nano-lithography.Object: NGC7000 & IC5070 or the North American and Pelican Nebulae HST - 2018 At last, the surface plasmons excited by the radially polarized focus are shown at the surface of the metallic film and form a smaller focus. The focus shift effect caused by the different sizes of nano-holes provides the mechanism for changing the longitudinal position and the lateral resolution of the focus in subwavelength scale. Additionally, we simulate the focusing of radially polarized beam through dielectric half ball shaped nano-holes with different sizes. The distribution of electric field of the focus obtained from the FDTD results coincides with that directly calculated by Debye theory, which proves the facility of FDTD method for simulating the focusing optical field. We simulated the focusing processes in single dielectric medium and through the interface of two dielectric media, respectively. The electric field of radially polarized focal beam in a defocus plan calculated by Debye theory is induced as input source using the total/scatter field approach. The finite difference time domain(FDTD) method is applied to simulate the focusing of radially polarized beam. The equations of vectorial three dimensional(3D) electric field of radially polarized beam focused by high numerical aperture objective are given based on the vectorial Debye. The strong lateral polarization component of radially polarized beam focused by high numerical aperture objective shows totally axis-symmetrical property, which gives rise to its widely applications in many optical devices. However, how different antenna parameters affect the results has to our (see IEEE VTSĤ6th Vehicular Technology Conference Proceedings, vol.3, p.1643-46,ġ996) it was found that space diversity yields typically about 1 dBīetter “diversity gain” than polarization diversity. Polarized in two orthogonal polarizations, e.g., horizontal/vertical or Polarization diversity two antennas are also used but there is no needįor any physical separation between them. Separated by several wavelengths to receive “independentlyįading” signals. Theĭisadvantage with this method, however, is that the antennas have to be Until recently this was done by using two separateĪntennas positioned some distance apart from each other. One way toĬombat multipath fading on the uplink is to implement a diversity schemeĪt the base station. However, a major problemįor cellular systems is the multipath, or short-term fading. Electron Comm Jpn Pt 1, 90(8): 1–9, 2007 Published online in Wiley InterScience (DOI 10.1002/ecja.20393 Copyright © 2004 Wiley Periodicals, Inc.Copyright © 2007 Wiley Periodicals, Inc.Ĭellular radio systems have been in operation since the earlyġ970s and are experiencing tremendous growth. In addition, if the patch is positioned perpendicularly to the horizontal plane, we show that the optimum dielectric remains virtually unchanged in the tilt plane up to about 15° from the horizontal plane. Next, we investigate the case where parasitic elements are mounted on the patch antenna, and use the FDTD method and test to show that our method is valid. Therefore, if the cross-polarization level during horizontal polarized excitation and vertical polarized excitation is the same dielectric, the lowest cross-polarization level can be obtained in conditions where both horizontal polarization and vertical polarization are decreasing cross-polarization. We learn from this that the direction of cross-polarization increase or decrease in relation to the dielectric is reversed during horizontal polarized excitation and vertical polarized excitation. First, we use a cavity model of the patch antenna to find cross-polarization dielectric characteristics in the tilt plane. At the same time, we clarify the limit values for the cross-polarization level. In this paper, we propose a method for decreasing cross-polarization in the tilt plane by optimizing the dielectric substrates of dual-polarized patch antennas.
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