Title page for etd-0729104-220612


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URN etd-0729104-220612
Author Chih-Hao Chang
Author's Email Address No Public.
Statistics This thesis had been viewed 5561 times. Download 2222 times.
Department Communications Engineering
Year 2003
Semester 2
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title A Study of the Effects of the Ground Plane and the Phase Center on the LPDA Antenna Factor
Date of Defense 2004-07-13
Page Count 78
Keyword
  • LPDA (Log-Periodic Dipole Array Antenna)
  • Antenna Factor
  • Ground Plane
  • Phase Center
  • Abstract Abstract
    Whether an Open Area Test Site (OATS) is qualified is based on the Normalized Site Attenuation (NSA). The purpose is to eliminate the influence of Antenna Factor (AF). Usually the AF provided by the manufacturer adopts the Standard Site Method (SSM) and is quoted from measurements at a 10-m range. In practice, the AF varies with the measurement conditions. This uncertainly will translate into error in NSA measurements. Currently radiated electromagnetic interference measurement mostly adopts the broadband antennas, and LPDA is one of the antennas used extensively. However, the AF provided by the manufacturer does not consider shifts in the phase center of LPDA with frequency. In the meantime the radiation pattern of LPDA is different from that of a short dipole. The investigation of this thesis will focus on these two parts.
    In determining the phase center of LPDA antenna we adopt the average shift of phase center to improve the AF. The numerical simulation results show that such an arrangement can result in improvement. We also use the method of PCPM (Phase Center and Pattern Matching) to modify the AF under different conditions of measurement when a ground plane is present. Our study, by using the numerical simulation and measurement, shows that this indeed improves the variation of AF over that obtained by SSM. In addition, efforts are also made to have a detailed discussion in mutually coupling effects between the LPDA antenna and the ground plane, in order to distinguish the impact on AF due to the coupling of the LPDA antenna and its image. Our numerical simulation results indicate that it does not have a significant effect.
    Advisory Committee
  • Chih-Wen Kuo - chair
  • Tzong-Lin Wu - co-chair
  • Ken-Huang Lin - advisor
  • Files
  • etd-0729104-220612.pdf
  • indicate accessible in a year
    Date of Submission 2004-07-29

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