Research And Design Of High Linearity Microwave Mixer

Mixer is an essential component of the RF microwave circuit portion in the moderncommunications systems. It must make the microwave signal down to low-frequencyand process in the microwave communications, radar, remote-control, remote-sensing,or electronic reconnaissance, electronic countermeasures, as well as microwavemeasurement system. As the development of the communication technology in variousfields of the people’s lives, we must design and develop a kind of communicationsystem which contains multi-standard transceivers can deal with multi-mode,multi-band signals. High linearity microwave mixer becomes an excellent option of themixer circuit in transceiver of the RF and microwave circuit system because of itsultra-wideband, low-noise, low local oscillator, good isolation and other goodcharacteristics.In this paper，firstly，the theory of microwave mixers is introduced in brief, andthen the principle of nonlinear device was researched on the basis of understanding andgrasping the principle of the production transistors ATF54143of the AVAGO company.Some ideal about the concept of designing circuit model was proposed based on theapplication characteristics and parameters of FET54143. Then the design of the balunwas achieved combined the frequency range and the applications of ATF54143withmicrowave circuit simulation software ADS. Microwave mixer which has a low-costand high-performance based FET was researched and designed in this article, it hasobvious advantages in the structure, process, the result of design compared with tradit-ional design method of microwave mixer. Then high performance mixers in thetransceiver circuits used in modern communication system was designed and simulatedwith the software ADS. Then the problems encountered in the design process wereanalyzed in-depth.Last the high linearity microwave mixer was measured with Agilent vectornetwork analyzer and spectrum analyzer, several experimental results aboutperformance indicator of the mixer was got by us, and the corresponding analysis tothese test results was done. When f(RF)=1GHz, f(IF)=100MHz, its conversion loss is as low as7dB, IMD3up to67dBm and port isolation reaches60dB，the IP3achieve13.5dBm. This paper achieve the target of research the high linearity microwave mixer,it can provide a reference to study the linearity of the mixer and the research andanalysis of further improve the overall performance of the communication system.