Millimeter-wave High-sensitivity Receiver Design

The exploitation of millimeter-wave band is promoted by both the increasingly congested microwave spectral region and the limitations of visible light and infrared systems when working under harsh environments such as smoke, clouds and night time. On the other side, with the development of millimeter-wave, it has established itself in a wide range of military and civil practical applications. And the millimeter-wave receiving te-chnique has acquired considerable progress.Based on the requirements put forward by a practical project, the design of a millimeter-wave high sensitivity receiver is completed in this paper. The front-end of the receiver adopts the typical structure of double-conversion, and transforms the signals from high frequency of W-band to narrowband Intermediate Frequency (IF) by means of down-conversion. Then the frequency synthesizer which has the sweep function is utilized to realize the search task for a 4GHz bandwidth. In order to meet the demands of high sensitivity, the channelized receiver based on the double-sweep structure is used as the IF receiver, and an output bandwidth of 10 KHz is achieved through the combination of rough sweep and fine sweep. In addition, the output of the IF receiver is compared with a threshold to investigate whether there are output signals in this corresponding channel and the purpose of frequency measurement is achieved.The IF receiver is a key part in the whole system, so the implementation of frequency synthesizer, which is a crucial component of the IF receiver, is discussed in detail. At the same time, the scheme of hardware circuit is also presented. In this scheme, the output of DDS is used as the reference frequency of PLL and a CPLD is adopted as the controller. Furthermore, the output of ADF4360-7 is simulated by means of software.