Research Of The Ku Band Campact High-Power Microwave Output Window

The microwave output window is an important part of the high power microwave system. It possess the high sealing quality, and it could withstand the pressure between vacuum and atmospheric, also it has the high power capacity. As the high power microwave system is developing towards high power capacity and becoming compact, it puts higher requirements for microwave output window in high power microwave system. All aspects of research on microwave output window was carried out in the institution domestic and overseas, and some progress has been made.There exists different forms of output window and part of the technology is relatively mature. While there are always multiple demands in power capacity and compact structure for output window when some special requirements for high power microwave system are needed, such as the high power microwave radiation system. Therefore in this paper, we intend to explore new kinds of high power output window to satisfy the demands of high power radiation system.Firstly, the classification of the microwave output window was simply made, and we chose to seal the output window under the circular waveguide. As a fundamental structure of sealed output window under circular waveguide, the pillbox window has the advantage of larger power capacity, mature technology, simple and compact structure. As a result, based on the research of pillbox window, we research and design the Ku band pillbox window through the combine of equivalent circuit and numeric simulation method.Secondly, in order to enhance the power capacity, a plan to increase the diameter of the middle circular waveguide has been put forward. Combine with the microwave system connection requirements before and after the output window, we use the output window with rectangular waveguide input and circular waveguide output structure, and design a compact rectangular-circular converter. Through the analysis of the coupled wave theory, the transition section was designed, and the Ku band high power microwave output window was designed based on it. Then, the compact improvement for output window is made. Consider the sealing requirements in actual processing and the influence of the triple point to surface electric field intensity of a window, the structure was further improved and optimized. A kinds of raised structure on both sides of the middle window and the groove processing for the window surface was used for increasing the power capacity of the compacted output window.At last, based on the research and design above, we design and manufacture the high power compact output window structure. The standing wave ratio and insertion loss of the microwave output window are obtained from the test subsequently. The results show that, in the 12.4-12.65GHz the reflectance (S11) is less than 0.1, in the whole band,the insertion loss is less than 0.2dB. The designed power capacity reaches 7.6MW. The basically identically experimental and design results preliminary verify the feasibility of the compact high-power output window.