Adaptive Receiver Front-end And Tunable Filters

The current radar scout system has some problems for processing multiform signals, confronting the complex electromagnetic environment and various radar characteristic signals. The adaptive front-end in receiver can solve these problems, and this dissertation analyzes it. The adaptive front-end has the adaptive ability for the magnitude and frequency of input signals. It can prefilter for the input signals, eliminate the useless signals, and improve the dynamic range of receiver system. It can lessen the burden of digital signal processing in the back-end of receiver, and improve the performance of receiver system.The adaptive front-end contains the adaptive RF channel and the digital control. This dissertation gives the design project of this system, and analyzes each several part of this system. And this system is finally implemented by integrating MEMS apparatus, so the author investigates the new technology RF-MEMS, and finds out that the current RF-MEMS apparatus has some problems on practicability.The emphasis of this dissertation is the tunable filter in the adaptive RF channel. Concern the MEMS tunable filter and combline tunable filter. At first, give some design projects of MEMS tunable filter, that is maybe realized, base on investigating the MEMS technology. Secondly, base on the basic theory of filter, get the approximate equivalent model of combline filter and synthesis method of coupled microstrip lines by referring to a great deal data and deducing the formula. Finally, design and test microstrip combline tunable filter.