S-band Down-conversion Link

With the fast development of wireless communication system, The communication equipment which used in various radio frequency band emerges one after another incessantly. The down-conversion wireless communications link which play a mayor role in the RF receiver has become the research priorities and difficulty in the field of domestic and international wireless communications research. As a result of S wave band electromagnetic wave's particularity, the increasing numbers of communication equipments which based on the S wave band have more and more applications, and therefore the design of communications equipment for accordingly put forward new requirements. Based on the corresponding project indicators and in the deep research receiver structural design's rationale, links to this project reality, this article has gave the receiver structure that suited this design, and the overall performance simulation has been carried on to the whole down-conversion links with the ADS software. Specifically design out some of the major module of down-conversion link, after carried on the deep research to down-conversion link module of 2.0 ~ 2.4GHz frequency band. Through analysis the target request of each module that the down-conversion system assigned to, the selection of the device has been made. Finally, take this as the foundation the entire down-conversion system link has been built.Due to the low noise amplifier (LNA) at the first stage of down-conversion, it has a great impact on the noise of entire down-conversion system. So, the low noise amplifier suitable for this project's bandwidth has been designed use ATF54143 chip, which make the noise figure of whole system be greatly reduced. And the microstrip pre-select filter which can be used in bandwidth of this down-conversion has been designed use IE3D software. And the design of IF filter has been completed used ADS.