Study On High Performance Down-conversion Module Of Ku-band

With the developments of science and technology, the relevant technology ofmicrowave and millimeter-wave have been more and more important in the field ofmilitary and communications, so the frequency conversion module play a decisive rolein the entire transceiver system. The good and bad of the frequency conversion moduleperformance have a significant impact on the indicators of the system. How to achieve awider relative bandwidth in the higher band and how to be stronger anti-interferenceability and smaller energy loss become research trends of microwave and millimeterwave study, and lunched a hot competition between groups.The content of this thesis is about the high performance frequency conversionmodule in the Ku-band. Its input signal frequency range is14GHz±650MHz,andthrough the frequency conversion module, its output signal frequency range is1150±650MHz. Compared with the existing band conversion module, this module will bewider bandwidth (113%relative bandwidth), smaller noise, and its transmission gainwill become more flat and have a large dynamic range.Firstly, delineated the background of this topic to introduce the thesis. Then,according to the integral requirement of the Ku-band frequency down-conversionmodule, planed and determined the specific indicators parameters of various discretedevices. Thirdly, made a detail describe with each discrete devices and gave individualresult of test, which based on the introduced basic knowledge of low-noise amplifiers,filters, mixers. The main difficulties of the design are how to achieve the ultra-widebandof filter and the two LNA,how to achieve the low-noise and flatness gain requirementsof LNA. When designing the ultra-wideband UHF LNA, not only using the"cross"structure to match the input terminal as the Ku-band LNA, in order to improve thereflection of the input terminal, but also add the negative feedback and amplitudeequalizer structure into the framework of the output terminal respectively to make itgain flatness enough to satisfied and exceed the requirements of the indicators. Usingthe cascade form of the high-pass and low-pass filter in order to meet the requirementsof ultra-wideband and low insertion loss, at last the entire filter not only meet the indicators, but also the volume is also smaller.In the end of this thesis, completed testing both individual devices and the wholesystem of the designed Ku-band frequency down conversion. The overall test result forthe module in Ku-band is that the entire module gain is greater than20dB, and has avery good flatness, its noise figure is less than3.6dB, when two-tone input-40dBm, itsoutput third-order representative value is27.3dBc, and its1dB compression point ofapproximately is about10.8dBm, the image frequency and spurious signals areeffectively suppressed. Therefore, the test results show that the outcomes are met therequirements for the design of Ku-band frequency down-conversion module, that canwell suits the needs for curret market.