| W band is one of the atmospheric Windows of millimeter wave,whose frequency is between microwave and light,and has both advantages of microwave and infrared.It has a broad application prospect in electronic warfare,radar seeker,broadband satellite communication and cloud and rain detection radar,etc.Research institutions at home and abroad are actively carrying out relevant research.In the W-band application field,satellite communication has maneuverability,a wide coverage,large communication capacity,and is not restricted by geographical conditions,as a result plays a pivotal role in the communication field.With the vigorous development of broadband multimedia satellite communication,the frequency resources of C,Ku,Ka and other low-frequency satellite communication systems are increasingly strained.Satellite communication has wide applications and large market.In order to meet the growing demand for communication capacity and transmission rate of the communication systems,the working frequency band of satellite communication is developing towards the W-band,which has become the frontier of satellite communication application.Considering influences of communication rate,communication distance,atmospheric loss and other factors,the W-band satellite communication system needs a high-power source,so the research of the W-band high-power transmitter becomes an important basic research of application.In response to the above application requirements,the main research contents and innovations are as follows:1.Research on W-band folded waveguide TWT.In this paper,the high frequency characteristics of folded waveguide TWT are studied,and the dispersion characteristics,coupling impedance and transmission characteristics of the folded waveguide slow-wave system are mainly studied.The optimized size parameters are obtained by using the simulation software HFSS.By using simulation methods to study the characteristics of beam-wave interaction,the working performance under large signal was simulated.Under the working voltage of 16 kV,the working current of 80 mA,the input power of 10 mW,the output power of the travel wave tube was greater than 50 W in the frequency range of 90GHz~103GHz(bandwidth of 13GHz),and the gain was greater than 37 dB.2.Research on W-band staggered double vane TWT.In this paper,the traditional staggered double vane slow-wave system is optimized,and a step-type staggered double vane slow-wave system is proposed.A W-band step-type staggered double vane TWT is designed.The calculation results show that the coupling impedance is higher,the gain is 4dB higher than the traditional structure in the whole working band,and has lower saturation input power and higher interaction efficiency.3.Key technology research and engineering realization of high-density special high-voltage power supply.W-band TWT has high operating frequency and low electronic efficiency.In order to ensure sufficient output power,the cathode voltage of special high-voltage power supply needs to reach-15kV~-20 kV.The increase of cathode voltage means that the core energy transmission component of the high-voltage power supply--high-frequency transformer needs to overcome a series of problems,such as the difficulty in controlling the interlayer distribution parameters and mutual coupling characteristics of windings caused by extremely high voltage,the high withstand value of primary and secondary insulation,and the low efficiency of power transmission.In addition,the W-band TWT slow-wave structure,focusing system,electron gun and other parts are extremely precise.In order to maintain good phase and power stability,it is necessary to strictly control the cathode voltage stability of the special high-voltage power supply and optimize the temperature drift rate of the cathode voltage in the full temperature range(-55 ° C ~ 70 ° C).This paper studies the key technologies of high-voltage power supply,such as the high voltage planar transformer,high power and high-efficiency power conversion based on magnetic circuit integration,high-precision cathode voltage control,low-temperature drift control,high-voltage vacuum sealing technology,etc.,and completes the design and processing of high-voltage power supply.The test shows that the cathode voltage is adjustable from-15 kV to-17 kV,the cathode current is 85 mA,the efficiency is 92.3%,the size is 310mmx82.8mmx36 mm,and the weight is 1.7kg.4.Integration study of W-band high power transmitter.The main function of the W-band transmitter is to power-amplify the W-band RF signal.The transmitter consists of a preamplifier,a traveling wave tube,an isolator,a control detection circuit,a low voltage power supply,a high voltage power supply,and an EMI filter.The system power is sent to the low-voltage power module and the high-voltage power module through the EMI filter.The low-voltage power supply provides the working voltage for the control detection circuit and the preamplifier.The high-voltage power supply generates the high-voltage and timing control of the traveling wave tube through the internal high-voltage conversion.The traveling wave tube completes the final-stage power amplification.The control detection circuit completes the transmitter control and the working state detection and report.In order to meet the requirements of the transmitter's operating frequency range and output power,firstly study the suitable traveling wave tube,then study the design of high voltage power supply,RF channel and low voltage power supply according to the electrical parameters of the traveling wave tube.According to the system control,detection and protection requirements,control circuit and related software are designed.5.Engineering realization of W-band high power transmitter.Based on the research of transmitter integration,this thesis has carried out engineering research,completed the miniaturized modular design of the transmitter,high-strength and reliable heat dissipation structure design and electromagnetic compatibility design,completed engineering joint design and application integration of the W-band CW folded waveguide TWT.Finally the joint debugging and testing of the W-band transmitter was carried out,with input power ? 1mW,continuous wave output power in the range of 91 GHz ~ 97 GHz ? 51.2W,efficiency ? 11.2%,size ? 370 mm × 180 mm × 47 mm,weight ? 6.3kg,all indicators have met the target requirements. |
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