6′th International Conference on Advances in Computing & Communications, Rajagiri College of Engineering, Kochi, 7.9.2016.
A waveguide window is a passive device which serves to isolate the high vacuum inside the device from the atmospheric pressure outside while allowing electromagnetic energy to pass through the structure without significant degradation. The ideal window should have low power absorption, high transmission, high mechanical strength, and high thermal conductivity and should be able to hold the desired vacuum level of the tube. Windows can be used in many possible configurations in vacuum tubes depending on the bandwidth and power handling capability for various applications. For high power tubes, three different types of window configuration are generally used: the rectangular single block window, the multilayer window, and the thin disc pillbox window. The rectangular single block windows are rugged and have excellent transmission over a narrow band, whereas, the multilayer window and pillbox windows give a broadband performance. Material choice is very important when designing a microwave window due to the ultra-high vacuum environment. Materials like CVD diamond, Alumina, Beryllium oxide; sapphire4 and Quartz are mostly used in RF windows.