Introduction to antennas and its classification

1. LECTURE 1
RADIATION PATTERN
ECE6
Parismita A Kashyap

2. HISTORY
 The first antennas were built in 1888 by German
physicist Heinrich Hertz in his pioneering experiments to
prove the existence of electromagnetic waves predicted
by the theory of James Clerk Maxwell.

3. ANTENNA FIELD ZONES
•The dividing line
“Rule of Thumb” is
R = 2L2/.
•The near field or
Fresnel zone is r < R
The far field or
Fraunhofer zone is
r > R

4. CLASSIFICATION OF ANTENNAS
1. Based on operating frequency:
 Very low (VLF)
 LF
 MF (e.g Monopole and loop)
 HF (e.g Dipole)
 VHF
 UHF (e.g Yagi-Uda, folded dipole, small dish, helical, slot, UWB)
 SHF (e.g optical band antennas)

5. CLASSIFICATION OF ANTENNAS
2. Based on structure:
 Wire antennas
Dipole antennas

6. CLASSIFICATION OF ANTENNAS
2. Based on structure:
 Wire antennas
Folded Dipole antenna Monopole antenna

7. CLASSIFICATION OF ANTENNAS
2. Based on structure:
 Wire antennas
Loop antennas

8. CLASSIFICATION OF ANTENNAS
2. Based on structure:
 Aperture antennas
Horn antenna
Dish antenna

9. CLASSIFICATION OF ANTENNAS
3. Based on purpose:
 Travelling wave antennas
Rhombic antennas

10. CLASSIFICATION OF ANTENNAS
3. Based on purpose:
 Travelling wave antennas
Inverted-V antennas

11. CLASSIFICATION OF ANTENNAS
3. Based on purpose:
 Broadband antennas
Helical antennas

12. CLASSIFICATION OF ANTENNAS
3. Based on purpose:
 Broadband antennas
Yagi-Uda antennas Folded dipole
antenna

13. CLASSIFICATION OF ANTENNAS
4. Directional & Omdirectional antennas
5. Resonant & Non- resonant antennas

14. FIELDS FROM OSCILLATING DIPOLE

15. FIELDS FROM A HALF WAVE DIPOLE

16. BEAM AREA

17. SIMPLE DIPOLE ANTENNA

18. CURRENT DISTRIBUTION FOR Λ/2 DIPOLE

19. CURRENT DISTRIBUTION FOR DIFFERENT
LENGTHS

20. RADIATION PATTERN OF A DIPOLE
ANTENNA

21. MORE

22. RADIATION PATTERN OF HALFWAVE
DIPOLE

23. 2D PATTERN OF HALFWAVE DIPOLE

24. FOR DIPOLE AND MONOPOLE

25. CONTINUED….

26. FOR 1.5Λ

27. RADIATION PATTERN FOR LENGTH 1.25Λ

28. PATTERN FOR 1.25Λ

29. PATTERNS FOR DIFFERENT LENGTH