Fig 7.5: Plane wave intercepted by an antenna
Fig 7.5: Plane wave intercepted by an antenna
Let Pinc represents the power density of the incident wave at the location of the receiving antenna and PL represents the maximum average power deleivered to the load under matched conditions with the receiving antenna properly oriented with respect to the polarization of the incident wave.
We can write,
.................................(7.33)
where 
and the term Aem is called the maximum effective aperture of the antenna. Aem is related to the directivity of the antenna D as,
See Appendix 3 for more details
| Fundamentals of Antennas and Radiating systems |
the antenna. This is illustrated in Fig 7.5. The incident electric field sets up currents in the antenna and delivers power to any load connected to the antenna. The induced current also re-radiates fields known as scattered field. The total electric field outside the antenna will be sum of the incident and scattered fields and for perfectly conducing antenna the total tangential electric field component must vanish on the antenna surface. |