Research And Application Of Hard/Soft Tube Modulator Base On C-band Radar Transmitter

The radar finds the target and determines the parameters of the target height, distance, direction, speed by the special performance of a variety of radio waves reflected from the objects. Therefore, the radar will work when certain high-power RF signal transmission occurs. Transmitter has played a very important role in the radar and pulse modulator played a very important role in the radar transmitter. The development of modern radar demands more requirements of the RF performance of the pulse transmitter. Improving the RF amplifier tube of the amplitude and the phase sensitivity can only be a certain convergence. Adjusting the RF pulse quality needs to be done by the pulse modulator.With the development of radar technology and electronic semiconductor technology, radar modulator soft tube and hard tube have gradually become the main development direction of the radar modulator. Soft tube modulator is the relatively high efficiency one of the pulse modulator, not only in the radar transmitter, but also in the high-energy electron accelerators, industrial irradiation accelerator, the synchrotron radiation facility and other fields. The actuator and the power of the hard tube modulator can be grounded, simple structure and reliable work, therefore widely used in pulse transmitters.The main contributions of this thesis are as follows:In Chapter Ⅰ, the test platform C-band fully coherent pulse Doppler weather radar and the corresponding advantages and disadvantages of the radar transmitter were introduced.In Chapter Ⅱ, C-band radar was specifically introduced; its system components, the basic working principle and the main technical characteristics were analyzed.In Chapter Ⅲ, the composition and the working principle of soft modulation techniques based on the C-band radar were analyzed and presented.In Chapter Ⅳ, one kind of hard pipe modulator was analyzed and designed using PSM and pulse transformer coupling technologies, the final test was introduced. This hard pipe modulator using PSM technology which is widely used in the field of broadcast transmitters. With rarely applying in the radar transmitter, changing the original C-band radar structure and size to meet the requirements of the technical indicators in the C-band radar transmitter conditions are not necessarily required, which will make the C-band Doppler weather radar change the pulse width in the high pressure.The choice of the pulse modulator depends on the type of machine on the transmitter and the RF pipe. In general, the efficiency, reliability and life expectancy of the linear modulator are higher, with smaller of the volume and weight, which generally only used for lower power levels. The adaptability of hard switch modulator to a variety of pulse waveform is best, but the efficiency is relatively low because the voltage is higher and size and weight is correspondingly larger. So it should be considered all the factors to select the modulator.