PPT Slide
The United States Federal Communications Commission has adopted a modified version of the ANSI/IEEE C95.1-1992 R.F safety guidelines, which limit human exposure to electromagnetic fields from mobile communication devices.The mass normalized rate of energy absorption (SAR) is limited to 1.6 W/Kg averaged over 1 gm of tissue
A mobile telephone antenna must therefore, not only radiate at full strength in order to communicate properly with cellular towers, but also reduce the power density incident on the user's head
This necessitates the need for an antenna whose radiation pattern has a region of reduced radiation intensity towards the user