The Research And Design Of RF Transceiver System For Wireless Communications

Radio frequency transceiver circuits have a very broad range of applications.As we can see,not only in civil but also in military field, the development of mobile telecommunicaion and mobile computer technology push us to a new enviorment. With the developing information capacity of conmunication system,RF circits pay a very important role in radio communications.For the widely applications of RF technology,more and more fields need RF specialists,consequently,it is necessary to do much research on RF transceiver system for wireless communications.In this paper, according to the structure and composition of RF transceiver system , I give a detailed analysis and design from two parts in the system and circuit based on the design and simulation tools——ADS software.In the part of the basic principles, I talk over the correlative backgrounds,design theories and technique datas of RF transceiver system.In the other part of electrical architectures,I independently give out the designs of antenna,LNA,mixers,micro-strip filters,simulate the desiged circuits based on ADS,analysis and option the results,come out the required designs.Meanwhile,I design the micro-strip antenna choosing the rectangular one with it's reflection coefficient.I design LNA with AT41511BIJ in ADS's component library, confirm the transistor's working point, and measurement the S-parameters.By matching the in/out circuits,I get the meeted results. According to a different circuit topology , mixers will be divided into single-balanced mixer and double balanced mixer.I begin the research on the two-mode mixers.By using a 3dB directional coupler,transistors and matched circuits,we can get a single-balanced mixer.After simulating this single-balanced mixer,we can get the perfect reflection coefficient and isolation.Because the double-balanced diode mixers have excellent performance thet they always work at switching states,I design a double balanced mixer with four transistors. By the simulation of a three-port frequency response is not very good, so the three-port circuits are matched. The simulation results show the isolation in three-port is good, little signal leakage.In the design of the filter circuit,I use two ordinary microstrip line Mlinls and five parallel coupled-line Mcfils to constitute the basic structure.After simulating,Port-band attenuation and reflection coefficient meet the design requirements. Thinking to the advantages of ADS, we can implement the various parts of the simulation circuit design and analysis the RF transceiver system's performances. The results show that using ADS software can reduce design costs, implement design specifications,so it can be effectively applied into the RF transceiver system design.