| Due to the advantages of wide bandwidth, high resolving power and etc, millimeter wave (MMW) becomes interesting to people now. Among its successful application, the research of small-size, low-cost and high-performance radio frequency front-end is very important. In this thesis, a simple MMW Doppler velocity-measuring radar is developed, which works at Ka-band frequency. In addition, a small-size digital frequency counter is designed, which can be used to analyze data from Doppler signal. Two transceivers are designed according to the technical demand. In one transceiver, Gunn device and mixer diode are mounted in the same waveguide cavity. In addition, video-frequency amplifier is combined with radio frequency front-end so that it will become more compact. In the other, the two devices are mounted in two separate cavities. At the same time, frequency-stabilized cavity is used to enforce the ability of anti-load and the conventional isolator is discarded. Therefore, the cost is further reduced while the characteristics of small size and stable performance are well persevered. Finally, a digital frequency counter is designed on count of the whole performance of the system. The new characteristics of this thesis are the ingenious design and the realization of the small size and low cost of the system, which lays foundation for the successful application of MMW Doppler radar. The system in this thesis can be used in many occasions such as the bug, velocity measuring radar and so on. Lastly, some advices have been presented on the design and experiment process, which will be useful to the further study of the system. |
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