Impedance Matching Network Design for Class C Power Amplifier

Abstract

Power amplifiers (PA) are typically the most power-consuming building blocks of RF transceivers. Therefore, the design of a high-efficiency radio frequency power amplifier is the most obvious solution to overcoming the battery lifetime limitation in the portable communication systems. In order to obtain the maximum output power, the reference impedance (usually 50 Ohm) must be transformed to the optimum input and output impedance of the selected transistor. Matching networks are therefore necessary at the input and at the output of a power amplifier circuit. In this research we designed a class C power amplifier operates in frequency range (200MHz -500MHz) with input power 0.63watt and output power 10watt. At high radio frequencies, the spurious elements (like wire inductances, interlayer capacitances, and conductor resistances) have a significant yet unpredictable impact on the matching network. In our design the matching network for input and output is implementing for frequency range (300MHz-350MHz) because of the wide band frequency range for transistor used.

Keywords

• amplifier design
• High frequencies
• microwave amplifiers
• Class C power amplifier
• smith chart
• voltage standing wave reflection