-In digital world, data is read and written in binary: 0 or 1.
-0 and 1 should be representable via some pattern. So each unique pattern is mapped to either 0 or 1.
-By breaking down a continous stream of data (sent by any program) into collection of those patterns, can be deduced an array of 0s and 1s (out of the continous stream of data ).
-In the wireless parlence, Data is sent via Radio Waves. Each wave has a trouph and a crust, which is a pattern. Thus pattern of these trouphs and crusts of the radio waves is used to represent data in wireless communication.
- Radio wave has its Electric and Magnetic Field.
Electric field propagtes in the direction of the Wave.
Magnetic field emanates in the direction, perpendicular to the wave.
These radio waves can be generated with primarily, two orientations: Horizontal and Vertical.
(1)if i send data in horizontal path(way), and the receiver expects to receive it as on a vertical path(way) and thus listens for the data vertically, then the receiver will be able to listen to a dot only (the intersection of the horizontal and vertical path)
(2)if i send data in vertical path(way), and the receiver expects to receive it as on a vertical path(way) and thus listens for the data vertically, then the receiver will be able to listen/receive the entire data (the intersection of the two vertical paths will be the entire vertical path)
(3)if i send data in horizontal path(way), and the receiver expects to receive it as on a horizontal path(way) and thus listens for the data horizontally, then the receiver will be able to listen/receive the entire data (the intersection of the two horizontal paths will be the entire horizontal path)
From (1),(2) and (3), it is clear that unless the physical orientation of the receiving antenna and that of the radio-waves(being-received by the receiving antenna) won't match, wireless data will not be received appropriately.
Every antenna has its fixed orientation. Depending on the orientation of an antenna, radio wave of that orientation is generated. Hence, orientation of the antennas in point-to-point 'wireless' link, MUST match.
Thus, so that the antenna element of an antenna be able to receive data within the radio waves, appropriately, as sent by the antenna element of the other antenna, it is important for the antenna element of the receiving antenna to know of the orientation(horizontal/vertical) of the being-received radio waves, so that both antennas can be aligned accordingly. This is what we term as Antenna Alignment.
Orientation of radio waves = polarization.
So, the resultant wave and polarization of an antenna is determined by the Electric Field emanating from the antenna element of a given antenna.
if we have vertically polarized antenna, its electric field will radiate vertically but horizontally will be radiated the magnetic field.
if we have horizontally polarized antenna, its electric field will radiate horizontally but vertically will be radiated the magnetic field.
So if we try to align two given antennas, in say, a point-to-point link, and the polarization of the two antennas doesn't match, those antennas can NEVER be aligned !
Example can be taken of light spread via perforated cardboard sheet.
The radiation pattern of an antennna can be studied by looking at the radiation pattern from two different views:
E plane: Elevation Plane (vertical plane) helps to visualize an antenna's radiation pattern's side-view indicating the width of the beam.
H plane: Horizontal Plane helps to visualize an antenna's radiation pattern's top and bottom view
if a radio wave propagates in an up and down , then up and down and , then up and down : vertical polarization
if a radio wave propagates in left and right , then left and right , then left and right : horizontal polarization