- An antenna is an electrical conductor or system of conductors
* Reception - collects electromagnetic energy from space
- In two-way communication, the same antenna can be used for transmission and reception
Antenna Definition
An antenna is a circuit element that provides a transition form a guided wave on a transmission line to a free space wave and it provides for the collection of electromagnetic energy.
In transmit systems the RF signal is generated, amplified, modulated and applied to the antenna.
In receive systems the antenna collects electromagnetic waves that are “cutting” through the antenna and induce alternating currents that are used by the receiver.
Polarization
Polarization is the direction of the electric field and is the same as the physical attitude of the antenna.
- A vertical antenna will transmit a vertically polarized wave.
The receive and transmit antennas need to possess the same polarization.
No comments:
Post a Comment