Hanyang University ANTENNA THEORY by Constantine A Balanis
Hanyang University ANTENNA THEORY by Constantine A. Balanis Chapter 2. 1 – 2. 9 Harim KIM 2017. 01. 20 1/40 Antennas & RF Devices Lab.
Hanyang University Contents 2. Fundamental Parameters of Antennas 2. 2 Radiation Pattern 2. 3 Radiation Power Density 2. 4 Radiation Intensity 2. 5 Beamwidth 2. 6 Directivity 2. 7 Numerical Techniques 2. 8 Antenna Efficiency 2. 9 Gain 2/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Definition : A mathematical function or a graphical representation of the radiation properties of the antenna as a function of space coordinates. - Field pattern : E & H fields’ magnitude (Linear scale. Angular Space) - Power pattern : Square of magnitude’s of E&H fields (Linear scale. Angular Space) - Power pattern : Magnitude of E & H fields (d. B scale) 3/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern 4/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Radiation Pattern Lobes Figure 2. 3 (a) Radiation lobes and beamwidths of an antenna pattern. (b) Linear plot of power pattern and its associated lobes and beamwidths 5/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Radiation Pattern Lobes - Isotropic, Directional and Omnidirectional Patterns 6/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Principal Pattern 7/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Field Regions 8/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Field Regions 9/40 Antennas & RF Devices Lab.
Hanyang University 2. 2 Radiation Pattern - Radian and Steradian 10/40 Antennas & RF Devices Lab.
Hanyang University 2. 3 Radiation Power Density 11/40 Antennas & RF Devices Lab.
Hanyang University 2. 4 Radiation Intensity The power radiated from an antenna per unit solid angel 12/40 Antennas & RF Devices Lab.
Hanyang University 2. 5 Beamwidth The angular separation between two identical points on opposite side of the pattern maximum. 13/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity The ratio of the radiation intensity in a given direction from the antenna to the radiation intensity averaged over all directions. 14/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity - Partial directivity : “part of the radiation intensity to given polarization divided by the total radiation intensity averaged over all directions” 15/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity Figure 2. 13 Two- and three-dimensional directivity patterns of a λ/2 dipole. 16/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity - Directional Patterns With approximation Directivity calculated 17/40 can be Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity - Directional Patterns 18/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity - Omndirectional Patterns We can approximate omnidirectional patterns by 19/40 Antennas & RF Devices Lab.
Hanyang University 2. 6 Directivity - Omndirectional Patterns 20/40 Antennas & RF Devices Lab.
Hanyang University 2. 7 Numerical Techniques A MATLAB and FORTRAN computer program called Directivity has been developed to compute the maximum directivity 21/40 Antennas & RF Devices Lab.
Hanyang University 2. 8 Antenna Efficiency 22/40 Antennas & RF Devices Lab.
Hanyang University 2. 9 Gain - Gain : “the ratio of the intensity, in a given direction, to the radiation intensity ” - Relative Gain : “the ratio of the power gain, in a given direction, to the power gain of a referenced antenna in its referenced direction” 23/40 Antennas & RF Devices Lab.
Hanyang University 2. 9 Gain - Gain is related to the directivity - Maximum value of the gain is related to the maximum directivity 24/40
Hanyang University Thank you for your attention 25/40 Antennas & RF Devices Lab.
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