Based On The Td-scdma Lte Doherty Transceiver Module Design Of Application

In modern wireless communication system, power amplifier is the largest part of energy consumption in the entire system. Therefore, its efficiency is one of the factors determining the performance of the entire system with a direct bearing on the cost and stability of it. Higher efficiency not only lowers electric energy consumption, operating cost and cooling demand, but also enhances the stability of equipment to achieve reliable system performance.In3G era, the signal formats of civil communication technology commonly have the feature of higher peak-average power ratio (PAR) which places more rigorous and demanding requirements on linearity and efficiency of the RF power amplifier. Traditional back-off power technique can not meet the need of high-efficiency and low power consumption for civil communication products. More efficient as GaN is, it has not been widely used for commercial purpose. Its high cost, which3-4times that of LDMOS, cannot be accepted by civil communication product manufacturers. Therefore, improving efficiency of power amplifier based on low-cost LDMOS will still be a main technique in the future.At present, popular amplifier efficiency enhancement techniques are Kahn EER technique, Envelope-tracking, LINC and Doherty. Compared with the previous three, which all need complicated line construction, additional envelope detector and signal modulator, Doherty technique becomes a main amplifier efficiency enhancement technique with its advantages of simplification, low-cost, small impact on system linearity, high practicality and easy mass production.Based on conventional Doherty technique, a Doherty transceiver module at2.6GHz applied in Time Division Duplexing was designed in this thesis.Starting from the basic principle of the Doherty amplifier, the author analyzes the reasons why the Doherty amplifier can enhance the amplification efficiency and explains the active load-pull theory derivation process. Meanwhile, the important role of the compensation line in the Doherty amplifier; the asymmetric structure Doherty and the multistage Doherty are also introduced in this paper. In the end, the actual designing process of an engineering product is taken as an example to explain how to use NXP’s BLF7G27LS-100and BLF7G27LS-140to design an asymmetric Doherty power amplifier with two-way transmitting and two-way receiving in a cavity. When the average output power is46dBm(40W), the PAPR is8.5dB the efficiencies of Transceiver is beyond30%, while the noise figure is1.4dB.This transceiver module is researched and developed on the high technical requirements of a domestic communication product manufacture. All crucial indexes of the module meet the requirements after testing and using, which are helpful for further researches on similar products.