Research Of TDD/FDD Front-end If Subsystem Technology In Ka-band

Today, as the increasingly shortage of wireless spectrum, and for the growingrequirement of wireless communication, it is the only way to develop wirelesscommunication in higher frequency under the situation that the unused lower spectrumis less and less. So nowadays, microwave and millimeter wave communication is thefocus of all countries.This paper talks about Ka-band front-end communication system and therealization of IF subsystem and control subsystem. This IF system can implement thetransmission and receiving function both for FDD mode and TDD mode simultaneously,also, this system could response the choice signal for different work mode and controlof front-end system. For the character of high frequency, it is ease to be interfered, thecontrol function of all the front-end system signal is realized in IF system. This paper isarranged as follows.Firstly, this paper states background of this thesis and current situation of Ka-bandcommunication, also there is a summarizing of the basic work of this paper. Then thereis an introduction of transmitter and receiver of wireless communication system, as wellas an analysis of performance indications of modern wireless communication, that canbe the indicators of test work.And then according to system indicator requirements, I design my general systemscheme. After that there is a statement of IF subsystem and control subsystemimplantation according to the general system scheme, including design andimplementation of chips selection, mixer circuits, AGC loop circuits and duplexer, andthen the circuits above are tested. Finally, the work is finished.Last are the test work of indicators according to the designed system andrequirements of signal by communication system. By the test results, someimprovement must be made for those indicators that do not meet the requirements ofdesigned system. By those steps, we can realize the required system finally.My paper states the character of the final system scheme, and realizes the requiredfunction according to test results. Although control system is designed very simple, it can achieve its required function very well, IF system can meet all the designedfunctions too. Both of them are adequate preparation for success of the whole front-endsystem.