The characteristics of an antenna used in a transcevier system are studied by several researchers in detail. These characteristics are mainly the radiation pattern, input impedance and the gain of the antenna. This paper proposes a new antenna suitable for cellular #,hone applications to reduce hazardous electromagnetic radiation toward humans. The antenna is shielded with PEC and shield is coated by alossy magnetic material. When magnetically shielded antenna is used, it is shown that near electric field toward user drops significantly.

Radio frequency spectrum is expensive and sophisticated modulation techniques, leading to wide, dynamic signals require linear amplification. The penalty for achieving linearity is efficiency. The challenge is therefore to develop power amplifiers which offer high linearity and high efficiency in the back-off. In this paper, the idea of Modified Doherty Amplifier Ill is extended by using a push-pull class-B amplifier in place of class-AB amplifier and a complementary class-C amplifier in place of single ended class-C amplifier to improve linearity and to provide high efficiency in back-off.Index Terms -power amplifier.

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