Analysis Implanted Spiral Microstrip Antenna With Fdtd

Microstrip antenna is a antenna which is made of a conductor on a dielecticsubstrate and covered with sheets. The first proposed by Drschamps in1953, but the technology is relatively backward and has not been greatly developed at that time.1970s, with the development of science and technology, especially copper and silver cover on the substrate and antenna measurement technology, microstrip antenna have the large-scale development. In this paper, the finite-difference time-domain(FDTD) is used to analyze microstrip antenna, And divided into three parts:First:This paper describes the finite-difference time-domain principle. Mainly related to Maxwell’s equations discrete at the FDTD, numerical stability and dispersion characteristics, the perfectly matched layer, Simulating sources, Near-and Far-Field extrapolation techniques, and the calculation of scattering coefficient. Then the author gives the radiation pattern of a element current.Second:The authors proposed a microstrip antenna which fed by microstrip, and calculate the parameters by FDTD method. Then optimize the antenna, to make the antenna worked at10GHz, show good agreement of this antenna. It can be used in high-frequency electromagnetic communication system. Then authors proposed a Aperture-coupled microstrip antenna which can be calculated by FDTD method, and compared to the results which calculated by HFSS software.In recent years, Ultra-wideband wireless communications antenna in its low power, high bandwidth, low-complexity and other advantage aspects are concerned by people, However, some bands are allocated to the WLAN, in the design of the antenna, the antenna must be not working at this band. That requires a band-stop function. With the HFSS software simulate an Ultra-wideband monopole antenna, the authors conducted a study of it. And open circular groove to achieve the band-stop function method(4.92GHz-5.75GHz). Basically meet the requirements.Third:Further study is about the characteristics of the microstrip antenna covered by dispersion medium, and calculate the parameters of the antenna. References to two dispersive mediums:plasma and biological media. To analysis the dispersive media, we construct the cold plasma model, using the more common Z-transform method. The chapter first studied the changes of microstrip antenna which covered by plasma, then follow the plasma antenna encapsulation method, covered with a layer of biological tissue on media package,then calculate the parameters. Finally calculate the parameters of Aperture-coupled microstrip antenna which covered by plasma. Based on the above three cases, we found that the dispersive medium on the electromagnetic wave with high frequency passed and low frequency hindered.