ANTENNA I Chapter 2 Antenna Fundamentals III 1

ANTENNA I Chapter 2: Antenna Fundamentals (III) 1 M. S. Bayati, Electrical and Electronic Engineering Department, Razi University

Chapter 2: Antenna Fundamentals A radiation pattern (also called an antenna pattern) is a graphical representation of the radiation (far-field) properties of an antenna; a general example radiation pattern is shown in Fig. We saw from the analysis in the previous section that the radiation fields from a transmitting ideal dipole antenna vary inversely with distance, e. g. , 1/r. This is a general property for antennas of all types; that is, the radiated fields observed far from any antenna decay with distance as a spherical wave. The variation with observation angles (θ, φ), however, depends on the size and construction details of the antenna. In fact, the relationship of an antenna to its radiation pattern forms a large part of antenna investigations. 3 ( ﺍﻟگﻮﻫﺎی )پﺘﺮﻥ ﻫﺎی. 4 : ﺗﺸﻌﺸﻌی ﺩﺭ ﺍیﻦ ﺑﺨﺶ ﺗﻐییﺮﺍﺕ. 1 -4 ﻣیﺰﺍﻥ ﺗﺸﻌﺸﻊ ﺑﺮﺣﺴﺐ ﺯﺍﻭیﻪ . ﺑﺤﺚ ﻣی ﺷﻮﺩ

Chapter 2: Antenna Fundamentals ﺍﻟگﻮﻫﺎی ﺗﺸﻌﺸﻌی. 4 : ( )ﺍﺩﺍﻣﻪ reactive near field reactive fields dominate over the radiation (real-valued) fields and the radiating near field where the The region interior to the far field ﺷﺮﺍیﻂ ﻣیﺪﺍﻥ ﺩﻭﺭ ﻭ ﻧﻮﺍﺣی. 3 -4 : ﻣیﺪﺍﻥ , called the near field, is divided into the where the radiation fields dominate over the reactive fields. 8