Antenna Radiation Direction--Antenna Direction
Antenna has two basic functions:
1. radiates the energy into space from the transmission line.
2.radiates most of the energy to the desired direction.
A vertical placed half-wave dipole antenna has a "donut" shape 3-D radiation pattern (Figure 3.1a). From the vertical plane (Figure 3.1b), the maximum radiation is pointing at the horizontal direction. From the horizontal plane (Figure 3.1c), the radiation is equal to all directions.