BS in Electrical Engineering
Electrical Engineering Department
As the demand for more devices to become wireless increases, there is a need for linear, efficient monolithic power amplifiers to deal with the variations in modulation of signals. With partial support from Cal Poly C3RP Grant #52268, this paper explains the implementation of and analyzes a circuit that actively biases a bipolar transistor to operate as a Class C amplifier. The Class C amplifier can maintain constant conduction angle over a range of output powers by using a Class B amplifier to force a scaled DC current vs. input magnitude curve on to a Class C amplifier. The knee in the current voltage characteristic of the amplifier is addressed and compensated for when building the circuit. A two tone intermodulation shows the linearity of the amplifier. A linear constant conduction angle amplifier with a conduction angle of 137 degrees is presented.