Some of the well-known types of it are as follows:. Yagi-Uda: Yagi-Uda is the directional antenna and is also known as the Yagi It is the most common type of antenna and is used in old household appliances like TVs and Radios.
In this type, many numbers of parallel elements half-wave dipoles are arranged in a single straight line. It is used as a bridge in TV reception. Aperture: An antenna with the opening that is capable of radiating the energy is known as the Aperture antenna. The opening of this is known to be the aperture. These types of antennas have the capability to send and receive signals in all directions, and the radiation is also more significant than the two-wire transmission line.
These kinds of antennas are used in surface search radars and microwave applications. Horn antenna is a well-known aperture antenna. Reflector: It is an antenna that consists of one or more reflecting surfaces with a system that transmits or absorbs the electromagnetic waves. These antennas are primarily used in satellite communication and remote sensing.
Parabolic reflectors and corner reflectors are examples of reflector antennas. Wire: It is the radio that is made up of long wire.
The length of the wire antenna has no relation with its wavelength. The cable is connected to the transmitter or the receiver via an antenna tuner to help catch or transmit the signals. Wire antennas are known for their portability and ease of installation. The types of the wire antenna are Dipole antenna, Helix antenna, and Monopole antenna. Lens: The electromagnetic lens is embedded in this antenna. It uses the convergence and divergence property of the lens to receive and transmit signals, respectively.
This type consists of a dipole antenna with a lens in it. The size of the lens is inversely proportional to the frequency of the signal that is to be transmitted or received. Natural language processing NLP is the ability of a computer program to understand spoken and written human language. NLP programming automates the translation process between computers and humans by manipulating unstructured data words in the context of a specific task conversation. View Full Term. By clicking sign up, you agree to receive emails from Techopedia and agree to our Terms of Use and Privacy Policy.
An antenna is a transducer that converts radio frequency RF fields into alternating current or vice versa. There are both receiving and transmission antennas for sending or receiving radio transmissions. Antennas play an important role in the operation of all radio equipment. They are used in wireless local area networks, mobile telephony and satellite communication. Antennas have an arrangement of metallic conductors with an electrical connection to receivers or transmitters.
Current is forced through these conductors by radio transmitters to create alternating magnetic fields. Wireless communication is the only feasible option and Antennas are the gateway for that. There are many situations or applications where cables are preferred over wireless communication with antennas like high speed ethernet or the connection between gaming console and the T.
Now that we have seen a little bit about antennas in general and why do we use antennas, let us proceed further and take a look as different types antennas. There are several types of antennas and each literature work has its own classification of antennas. Let us now briefly see about few of these different types of antennas. One of the most commonly used antennas are wire antennas. They can be found in vehicles automobiles , ships, aircrafts, buildings etc.
Wire Antennas come in different shapes and sizes like straight wire Dipole , Loop and Helix. Perhaps the simplest of all antennas is the Short Dipole Antenna. It is a special case of the Dipole antenna. In its simplest form, it is basically an open circuit wire with the signal being fed at the centre.
For a typical Short Dipole Antenna, the length of the wire les less than the tenth of the wavelength of the frequency of operation. A Dipole Antenna is made up two conductors in the same axis and the length of the wire need to be small compared to the wavelength. A Loop antenna is formed by a single or multiple turn of wire forming a loop.
The radiation produced by loop antenna is comparable to a short dipole antenna. A special case of Dipole antenna is the monopole antenna i. A class of directional antennas, Aperture Antennas have an opening in the surface.
Usually, aperture antenna consists of Dipole or Loop Antenna in a guiding structure with an opening to emit radio waves. A type of aperture antenna which contains one or more slots cut on the surface of the waveguide. They are usually used in microwave frequencies and have an omnidirectional radiation pattern.
One of the most popular antennas is the Horn Antenna, which effects the transition between transmission line and wave propagating in free space.
It acts as a natural extension to a waveguide. By now, we have a basic understanding of an antenna and how it is an essential component in a Wireless Communication system. The next important thing to understand is that the characteristics of a typical wireless communication system are dependent on the characteristics of the antenna used in the system. For example, the operational characteristics of a communication system find back its roots to the directional characteristics of the antenna.
Irrespective of the application that an antenna is used in, all the antennas are associated with a few fundamental parameters. These parameters are sometimes also called as Properties of Antenna or Characteristics of Antenna. Certain basic characteristics of antenna are listed below:.
A practical antenna cannot radiate energy in all directions with equal strength.
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