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Information × Registration Number 0207U002317, 0102U002486 , R & D reports Title Developement of transmitters for 3 mm wave length Doppler radars popup.stage_title Head Vavriv Dmytro Mykhailovych, Доктор фізико-математичних наук Registration Date 24-01-2007 Organization Institute of Radio Astronomy of the National Academy of Sciences of Ukraine popup.description2 Theoretical and experimental studies directed at the development of powerful pulsed sources of radiation of the 3 millimeter wave length band based on spatial harmonic magnetrons with cold cathode to be used in radar systems with enhanced requirements to radar resolution and quality of signal processing have been carried out in this work. Modernization of the design of spatial harmonic magnetrons with coald cathode and the technology of their production have been performed what have resulted in increasing magnetron lifetime up to 10 000 hours and in improvement of the reproducibility of magnetron characteristics. Approaches to the optimization of the magnetron operation aimed at reducing of distortion of output pulses and increasing their stability have been proposed. Advantages of the application of a current source in the generator in order to realise generation by the magnetrons of pulses with almost rectangular shape of the envelope and to minimize intrupulse frequency modulation have been demonstrated. Peculiarities of the design of such current sources on the base of FETs have been considered. A possibility to produce short pulses without an essential complication of the generator circuitry has been investigated. It is shown that in this case to realize the best pulse shape, an optimal shape of pulses applied to the grid of the modulator tube should be formed. This approach has been tested and highly efficient transmitters with the pulse duration as low 20 nsec and the pulse repetition frequency as high as 30 kHz have been developed. Criterions on the selection of an optimal transistor type for the high voltage key depending on required parameters of output pulses and magnetron characteristics. The application of developed semiconductor keys has enabled for the development of compact, high-power magnetron based transmitter with the total volume of several liters only. Practical designs of 3 millimeter wave length transmitter for coherent ground and air based radar systems have been proposed and realized. The output power level of the transmitters is 4 kW with the average power of about 10 W. The life time of the produced transmitters is up to several thousand hours. The achieved characteristics are the best ones for this type devices Product Description popup.authors popup.nrat_date 2020-04-02 Close