Design Of 2GHz Class E Power Amplifier In Silicon-based Process

GaAs process is widely used in RF power amplifier design because of its high frequency performance, low loss, low noise, high bandwidth and large dynamic range. However, recently, the feature size of MOS device of silicon-based process is decreasing as the process developed. The cut-off frequency of SiGe BiCMOS is as high as 200GHz, which will satisfy the demand of RF power amplifier design. As the silicon-based process has lower price and higher yield, it’s necessary for us to study the design of RF power amplifier with silicon-base process.In this paper, the working principle and standard of power amplifier and the advantage and disadvantage of different kinds of power amplifier is introduced first. This paper also introduced the design principle of class E power amplifier and provided design method of class E amplifier worked at 2GHz and completed the circuit design and layout design. The pre-simulation and post-simulation was taken on the 0.18μm SiGe BiCMOS process. The circuit uses a cascade class E amplifier structure which is fully differential to make sure the transistor worked under the safe voltage. The drive stage of the circuit is a resonant amplifier which can provide the large driving signal with less power loss. Discrete component is used to design the matching network to insure high efficiency. The post-simulation result shows that on the supply of 3.3V power, the power amplifier can get the maximum output power of 30dBm with power added efficiency more the 50%. The power gain of this PA is more than 23dB and the input reflection is less than -15dB.This designed PA has a large output power and high efficiency and gives us a lot of experience about how to design RFPA of large output power and high efficiency in silicon-based process. What’s more, the relatively cheap SiGe process is used in this design which will reduce the cost of the circuit and make the fully-integrated transmitter chip possible.