RF Front-end Optimization And Simulation Of Blind Signal Measurement Receiver

With science and technology developing, electronic and electrical industry has been increasingly popular. Unexpectedly, the space electromagnetic environment has been dramatically deteriorated by more and more complex electromagnetic interference. In practical EMC test, the most commonly encountered problems are highly cost shielded room, oversized DUT and fixed equipment. Therefore, virtual dark room was put forward to deal with the above scenarios. It is still in research. In high speed railway EMC test, Blind signal measurement receiver can be used to solve field limitations. Blind signal measurement receiver, which belongs to virtual dark room technology, can easily extract electromagnetic signals without space limit. The key part of this receiver is RF front-end.This thesis was based on blind signal measurement receiver front-end structure, mainly discussing design, simulation and test of RF front-end modules including low noise amplifier, filters and mixer. Receiver channel was designed and simulated by advanced design system. Parameters of separate modules and overall system were scanned as well. The optimization process was detailed in circuit design, simulation, PCB test and electromagnetic compatibility.Firstly, characteristics of RF receiver were discussed. Then, the author simulated overall receiver performance. Combining practical demand, the design goals focused on three modules including LNA, filters and mixer. Impedance matching technology was used in optimization process. Main content includes:(1) LNA. The low noise amplifier module was designed by using high electron mobility transistor ATF531p8. Combining data sheet, the author analyzed the transistor characteristics, designed bias circuit, simulated stability factor and did input impedance matching in order to meet the design goals. (2) Filter. Based on basic principle and performance index, different types of LPF were compared by simulation results. The optimal proposal was determined by flatness in band, ripple and attenuation in stop-band.. When designing BPF, the low and high order Butterworth BPFs was simulated. The author optimized it by adding micro-strip line. (3) Mixer. Firstly, the working principle of Gilbert Cell was introduced. Then the mixers were separately designed by ADL5387 clip and NMOS transistor. The optimal proposal was determined by simulation results.In general, this thesis was based on initial blind signal measurement receiver project. Combining RF circuit design theory and experience, the author used various means such as component selection, circuit design, module simulation, PCB fabrication and post-test to optimize LNA noise and gain, LPF flatness, BPF attenuation and mixer conversion gain. The overall performance of blind signal measurement receiver was promoted.