Study Of L-band Receiving System Components

The L-band receiver of this thesis is designed for the satellite radar which receiving wave on the ground for imaging.The purpose of this thesis is the development of high performance L-band receiver system.The frequency source with two-loops,LNA and the front-end of receiver are discussed in this thesis.The reference synthesizer unit and down-converter unit are measured,and the measurement results are analyzed finally.The reference synthesizer unit is designed for supplying LO and clock frequency for the quadrature demodulation unit and digitized collect unit.The devices are choosed according to the target of the system.When designing the reference synthesizer unit,we choose the fractional-synthesizer which adoptΣ_Δmodulation because the integer-synthesizers are difficult to realize both good phase noise and fast channel switching at the same time. By simulating theΣ_Δmodulation and fractional and integer synthesizer,we present an new idea for the synthesizer's designing.The low noise amplifier and receiver front-end are cascaded in structure of down-converter unit.The importance thing of LNA design is the match circuit design. AGC is analysed in the design of the receiver front-end.In addition,the RF receiver based on multiplayer PCB is discussed in this thesis. Through introducing multiplayer PCB process,we have designed a RF receiver with low price,size-reduction,and good EMC.