Antennas and their types

here we are providing complete details about types of antennas

1. ANTENNAS AND WAVE PROPAGATION

2. ANTENNA: An antenna is a specialized  transducer  that converts radio-frequency (RF) fields into alternating current (AC) or vice-versa. An antenna is a device for sending or receiving electromagnetic waves

3. Antenna parameters: Radiation pattern Efficiency Bandwidth Directivity Gain

4. Types of antennas: Log Periodic Antennas Wire Antennas Travelling Wave Antennas Microwave Antennas Reflector Antennas

5. Log-Periodic Antennas It is a multi-element, directional narrow beam antenna that works on a wide range of frequencies.  This antenna is made of a series of dipoles placed along the antenna axis at different space intervals of time followed by a logarithmic function of frequency.

6. Types of log period antennas Bow-Tie Antennas Log-Periodic Dipole Array

7. Bow-Tie Antennas A bow-tie antenna is also known as Biconical antenna or Butterfly antenna . Biconical antenna is an omnidirectional wide-band antenna . A bow-tie slot antenna is designed for radar applications.

8. Log-Periodic Dipole Array These dipole-array antennas reduce in size from the back end to the front end.    During this operation, as the frequency varies , a smooth transition takes place along the array of the elements, which leads to form an active region.

9. 2. Wire Antennas Wire antennas are also known as linear or curved antennas. These antennas are very simple, cheap and are used in a wide range of applications.

10. These antennas are further subdivided into four types Short Dipole Antenna Dipole Antenna Monopole Antenna Loop Antenna

11. Dipole Antenna The dipole antenna consists of two metallic rods through which current and voltage flow . This current and voltage flow makes an electromagnetic wave and the radio signals get radiated.  This are mainly used in FM broadcasting.

12. Short Dipole Antenna It is the simplest of all types of antennas . This antenna is an open circuited wire in which short denotes “ relative to a wavelength” A Dipole is considered as short if the length of the radiating element is less than a tenth of the wavelength. L<λ/10  

13. Monopole Antenna A monopole antenna is half of a simple dipole antenna located over a grounded plane. the total power radiated is half that of a dipole. The directivity of these antennas become double compared to the dipole antennas. GSM, Bluetooth, and UWB  a re main applications

14. Loop Antenna A  loop antenna  is a closed circuit radio   antenna. Loop antennas are available in different shapes like circular, elliptical, rectangular , etc . They are widely used in communication links.

15. 3. Travelling Wave Antennas The antenna in which the standing wave does not exist along the length of the antenna is called traveling wave antenna. These antennas are of two types 1. Helical Antennas 2. Yagi-Uda Antennas

16. Helical Antennas Helical antennas are also known as helix antennas. As it is a traveling wave antenna, the current and phase vary continuously along the helical antenna . Because of their unique and special properties , helical antennas are widely used in simple and practical applications such as in radios and satellite communications.

17. Yagi-Uda Antennas A  Yagi antenna , also known as a  Yagi -Uda array or simply a  Yagi , is a directional antenna  commonly  used  in communication when a frequency is above 10 MHz.

18. 4. Microwave Antennas The antennas operating at microwave frequencies are known as  microwave antennas . These antennas are used in a wide range of applications . These antennas are classified into two types Rectangular Micro strip Antennas Planar Inverted-F Antennas

19. 5. Reflector Antennas An antenna  reflector  is a device that  reflect electromagnetic waves . These antennas are classified into two types Corner Reflector Antenna Parabolic-Reflector Antenna

20. Advantages of Antenna Ty pes ➨ Dipole Antenna :They are cheap and exhibits good gain.  ➨ Loop Antenna :They are cheap and not easily de-tuned by hand movements .   ➨ Helical Antenna : It is very directive antenna and provides good amount of gain. ➨ Microstrip Antenna :They are very simple and chip antenna. They are used in smart phone due to their thin structure. 

21. ANTENNA APPLICATIONS They are used in Radio Astronomy. antenna is used to cure breast cancer. Antennas can be extremely small.  iPhone has several antennas all built into that small case . Mobile satellite communication Used in GPS tracking Antennas are also used in Remote sensing and in defense radar. 

22. largest antenna in the world World's Largest Radio Telescope  Five-hundred-meter Aperture Spherical Telescope's (FAST) giant dish, China's state-run 

23. world's smallest antenna Developed by Indian scientist Chakraborty , a PhD student