Linear Antenna
- 2. INFINITESIMAL DIPOLE • (l >>λ) • symmetrical at the origin • Oriented along the z - axis
- 3. INFINITESIMAL DIPOLE • not practical • used to represent capacitor plate antennas • used as building block for complex geometries
- 4. INFINITESIMAL DIPOLE • (l << λ); (a <<λ) • I0 is constant.
- 5. INFINITESIMAL DIPOLE • Radiatd Fields
- 6. INFINITESIMAL DIPOLE • Far-field Region
- 7. INFINITESIMAL DIPOLE • Time - Average Radiated Power and Radiation Resistance • Directivity and Effective Aperture
- 8. SMALL DIPOLE • λ/50 < l ≤ λ/10 • symmetrical at the origin • oriented along the z - axis
- 9. SMALL DIPOLE • current distribution - triangular
- 10. SMALL DIPOLE • Radiation Resistance
- 11. SMALL DIPOLE • Approximatio of Fields
- 12. FINITE LENGTH DIPOLE • Length > λ/10 • current -assuming a very thin wire -I0 - constant - ceter fed; current vanishes at end points
- 13. FINITE LENGTH DIPOLE • electric field of a finite lenght dipole
- 14. FINITE LENGTH DIPOLE • Radiatd Fields
- 15. FINITE LENGTH DIPOLE • Radiation Resistance and Input Radiation Resistance • Directivity and Effective Aperture
- 16. HALF - WAVELENGTH DIPOLE • one of the most commonly used • radiation resistance - 73 ohms
- 17. HALF - WAVELENGTH DIPOLE • electric and magnetic field component
- 18. HALF - WAVELENGTH DIPOLE • Radiation Resistance and Input Impedance • Directivity and Effective Aperture
- 19. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS • antennas radiating into an unbounded medium • obstacles introduce alteration of overall radiation pattern
- 20. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS • Image Theory - virtual sources for the refletion • obstacles introduce alteration of overall radiation pattern
- 21. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS
- 22. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS
- 23. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS
- 24. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS
- 25. LINEAR ELEMENTS NEAR OR ON INFINITE PERFECT CONDUCTORS
- 26. end...
Editor's Notes
- #2: oldest, simplest, cheapest, versatile
- #4: - top-hat-loaded antennas ; -end plates are used as capacitive loading(current on dipole nearly uniform) ; negligible radiation- plates ; very small and thin
- #5: -very small and thin ;
- #6: -applicable for all region ex. the source; kr<1 nearfieldregion-energy imaginary stored ; kr = 1 radian sphere boundary from imaginary and stored to radiated
- #7: -applicable for all antenna finite dimension
- #8: -very small and thin ;
- #11: radiated power resistance is 1/4 of the infi ; shape sand patterns are the same
- #12: surrounding boundary ,. phase error max.,., D -largest dimension
- #14: subdivision of infinitesimal ; elemntfactor- type and direction of flow i ; space factor-current distribution along the space
- #15: subdivision of infinitesimal ; elemntfactor- type and direction of flow i ; space factor-current distribution along the space
- #16: subdivision of infinitesimal ; elemntfactor- type and direction of flow i ; space factor-current distribution along the space
- #17: tx char. imp. - 50 - 75
- #18: tx char. imp. - 50 - 75
- #19: tx char. imp. - 50 - 75
- #20: - practcally there is always an a ground as obstcl
- #21: for analysis purps - imgnry
- #22: for analysis purps - imgnry
- #23: for analysis purps - imgnry
- #24: image near
- #25: image near
- #26: for analysis purps - imgnry