Research And Implementation Of Concurrent Quadrature Dual-band RF Transceiver System

With the development of wireless communication technology and the continuous upgrading of communication standards, the demand for the mobile terminal which can satisfy different communication standards is increasing, and the intelligent terminal products which meet the different internet of things wireless communication protocols have been launched. The application of dual frequency transceiver system is becoming more and more widespread. At the same time, the fragmentation of the spectrum resources makes the frequency gap between the two frequency signals, which is needed by communication terminals in transceiver, increasing continually. The research of the dual band transceiver system is also facing some challenges. At present, there are only two architectures of the dual band transceiver system, that is, the architecture that two frequencies are both zero-IF and the architecture that two frequencies are both super heterodyne, which cannot meet the diverse needs of the system architecture, and which the device has a low reuse rate. After advantages and disadvantages of the existing concurrent dual band transceiver structure having analyzed, this paper puts forward the concurrent quadrature dual-band transceiver structure and dual frequency power detection scheme, the main research contents include:(1) On the basis of domestic and overseas research, a concurrent quadrature dual-band transceiver structure is proposed, i.e. one RF signal is zero-IF architecture, the other RF signal is super heterodyne architecture. Besides, the detailed mathematical deduction of the dual-band signal modulation and demodulation processes that is completed by this structure have been finished. As an example of this paper, we use ADS software to simulate the structure and analyze the simulation results.(2) Analyzing the limitations of the existing power detection scheme while it is applied to the dual band receiver, this paper proposes a dual band power detection scheme for dual band receiver. And the principle and implementation of the dual frequency power detection are described in detail.(3) According to the requirement of indexes and the feature of concurrent quadrature structure, the overall framework of the concurrent quadrature dual-band transceiver system is designed and implemented.Based on the link budget of transmitter front-end and receiver front-end,the chips selection and PCB design of each module have been completed,so as to achieve the simulation of transmitter and receiver link performances, especially the key indicators of the EVM, ACPR, flatness and so on. As the system test platform is set up, the key indicators in the transceiver link, such as phase noise, EVM, ACPR, flatness, etc., have been tested and analyzed.