What is meant by antenna ??
Antenna is a piece of wire or a metal rod used to transmit or receive signals. There are many antennas available now a days.
The most basic antenna is called "a quarter wave vertical", it is a quarter wavelength long and is a vertical radiator. Typical examples of this type would be seen installed on motor vehicles for two way communications. Technically the most basic antenna is an "isotropic radiator". This is a antenna which radiates in all directions as does the light from a lamp bulb. It is the standard against which we sometimes compare other antennas.
Antenna is a piece of wire or a metal rod used to transmit or receive signals. There are many antennas available now a days.
The most basic antenna is called "a quarter wave vertical", it is a quarter wavelength long and is a vertical radiator. Typical examples of this type would be seen installed on motor vehicles for two way communications. Technically the most basic antenna is an "isotropic radiator". This is a antenna which radiates in all directions as does the light from a lamp bulb. It is the standard against which we sometimes compare other antennas.
Yagi uda is also a type of antenna whose radiation will be more stronger in one direction only.You can clearly understand when you see its radiation pattern.
You can see that radiation of the antenna is more in one direction and less in other direction.
Please open the above image in new tab if you can't see properly..
The second dipole in the Yagi-Uda array is the only driven element with applied input/output source feed, all the others interact by mutual coupling since receive and reradiate electromagnetic energy; they act as parasitic elements by induced current. It is assumed that an antenna is a passive reciprocal device, then may used either for transmission or for reception of the electromagnetic energy.To increase the transmission power to greater kms the aperture of the antenna is increased so that the radiation pattern becomes more narrower and consequently the gain grows.You can understand still clearly by watching this video.
Thanks for watching.
