Research And Design Of Power Amplifier In Digital Transmitter

The RF power amplifier is the most critical component in the front end of the RF transmitter.Its function is to convert the low-power signal into a high-power signal,and then transmit the signal through the antenna.Output power and efficiency are one of the most important indicators.Low-efficiency power amplifiers waste a lot of energy,while the energy consumed is converted into heat,which affects the overall performance.In recent years,RF power amplifiers have developed rapidly and the form of transmitters has changed from traditional analog RF transmitters to all-digital transmitters.With the rapid development of wireless communication systems,in order to meet better signal transmission,RF signals usually use peak-to-average signals.While traditional Class A and Class AB power amplifiers achieve high efficiency at peaks,overall efficiency is significantly reduced for signals with peak-toaverage ratios.Digital transmitters are the key technology for next-generation communication products.They use modulation to convert peak-to-average ratio signals into digital signals,and use high-efficiency switching-type power amplifiers to amplify modulated signals to improve overall efficiency.It is in this context that this paper mainly does the following work: 1.Introduced the basic knowledge of power amplifiers,pointed out the shortcomings of traditional RF transmitters and the form and advantages of new digital transmitters.2.A power amplifier with energy superposition is designed for use in digital transmitter multilevel technology.The center frequency is at 1GHz,and its working principle is analyzed.The design process of the power amplifier and the impedance network matching process at the output end are described.The working characteristics are pointed out.It can operate normally when there is only one signal or two signals.Maintain high efficiency.3.The mathematics knowledge and working principle of outphasing power amplifier are described in detail.An outphasing power amplifier with operating frequency of 1GHz is designed.The design method and design principle of each part of the module are described in detail.The test is performed using an analog signal and a modulated outphasing signal to obtain an test result.