The document discusses various types of antennas, including frequency independent, wideband, broadband, multiband, and RFID antennas, highlighting their characteristics and design methods. It details the construction and operational principles of specific antennas like spiral and Vivaldi antennas, including their bandwidth enhancement techniques. Additionally, it outlines the frequency bands used in mobile communication and mentions different antenna structures and configurations such as fractal antennas.

5. Frequency Independent Antennas
Wideband Antennas
Broadband Antennas
Broadband Microstrip antennas
Multiband antennas
RF ID Antennas

6. Frequency Independent Antennas:
Wide band antennas
Frequency independent bandwidth in
octave range
Broadband antennas
Frequency independent bandwidth in
the range 40:1
Multiband antennas
Antenna resonate at different
frequencies.

7. Effect of frequency on
Linear arrays

13. Harmonic nesting method

14. Variable aperture antenna arrays

16. • Wideband antennas can implemented by
using Self complimentary structures also.

17. Spiral Antennas
• Self complimentary
1. Equiangular
2. Rectangular
3. Archimedean spiral
4. Conical equiangular

18. Equiangular Shape Archimedean Shape
 Self Complimentary Structure
 Lower losses
 Stability of phase centre
 Improved Axial Ratio
 Wider operating frequency
bandwidth

19. Radiation Pattern

20. Rectangular Spiral
• Frequency band 500MHz to 2 GHz
• 4 turns
• Inner and outer diameters 1.8 and 21 cm

21. Radiation Pattern

22. Archimedean Spiral

23. Archimedean Spiral

24. Log- periodic Antenna
• A log-periodic antenna (LP)
 Is a multi-element, directional, narrow-beam antenna
 Operates over a broad band of frequencies.
Log Periodic Tooth AntennaLog Periodic Dipole Antenna

26. Radiation Pattern

27. Conical Equiangular

40.  The bandwidth of a microstrip antenna is increased
by using a thicker and lower-dielectric-constant
substrate, or by using multi-resonator gap-coupled
and stacked configurations, or by cutting a resonant
slot inside the patch.
 However, with all of these methods, the bandwidth
of the antenna is limited by the probe's inductance
for substrate thicknesses greater than 0.06λo to
0.07λo.
 For substrate thicknesses larger than 0.07λo, the
bandwidth of the antenna can be increased by using
a proximity-feeding method.

44. Introduction – Vivaldi Antenna
• The Vivaldi antenna, sometimes referred to as or the Vivaldi
notch antenna, and also known as the tapered slot antenna
(TSA), is easy to fabricate on a circuit board, and can provide
ultra-wide wide bandwidth.

45. Vivaldi Antenna
• A Vivaldi-antenna is a co-planar broadband-antenna, which is
made from a dielectric plate metalized on both sides.
• Peter Gibson invented the Vivaldi antenna in 1978, in the UK.
• By properly designing the Vivaldi elements to reduce mutual
coupling, antenna arrays can be designed to operate over a decade
of frequency and to scan more than 45 degrees from broadside.

46. Vivaldi antenna

51. Multiband Antennas

52. •Different Frequency bands for mobile communication:
 GSM 900/1800/1900 bands (890-960 MHz and 1710-1990 MHz);
UMTS 3G expansion bands (1900-2200 MHz and 2500-2700 MHz);
 Bluetooth & Wi-Fi (Wireless Fidelity)/Wireless Local Area
Networks (WLAN) bands (2400-2500 MHz and 5100-5800 MHz).

53. Fractal Antennas:

62. Multi Band Antennas
Quad-band Antenna for Wi-Fi and WLAN Spiral-Shaped Multi-Band Antennas

63. Structure of Layers Geometry of the Antenna Element
Multi-band microstrip patch antenna

64. RFID Antennas

99. Questions ?

100. Thank You