Research On Theory And Experimental Of Terahertz Extended Interaction Oscillator

Due to its special position in the electromagnetic spectrum between microwave and optics, terahertz (THz) wave of has enormous potential application for high data rate communications, advanced electronic materials spectroscopy, space research, medicine, biology, surveillance, and remote sensing. However, the terahertz source is the bottle-neck for these applications because of its low power, low efficiency and large volue. It is the key point and primary task for this area to develop the suitable terahertz source. Vacuum electronic devices (VEDs) have shown the strong capacity in millimeter-wave, even in terahertz region. The extended interaction oscillator (EIO) is one of the most important devices in VEDs. This dissertation presents the theoretical research on Extended Interaction Oscillator, and the research of round and sheet beam electron gun, and the experiments of various EIO`s in kinds of frequency region.The foundmental works and the distinguished results are showen as follows:1. The folded wave guide is utilized as the slow wave structure (SWS) of THz EIO. The transmission characteristics of the folded wave guide are theoretically studied by the mens of principle of the equivalent circuit and rigorous electromagnetic wave theory. The geometry optimize and partical simulation have been corried out useing several commercial softwares by adjusting different parameters. The simulation results are well agreed with the theory. According to previous theoretical work, the folded wave guide geometry is determined for EIO working at 0.1THz.2. Another novel slow wave structure, rectangle cavity structure is proposed and researched in the dissertation. Under the sheet beam excitation, the high TM31 mode well can be excited with the sheet beam. With this structure, the EIO can work at high frequency under the recent fabrication technology. The sheet beam interacts with TM31 mode at 2Ï€point. So, The EIO has strong capability of interaction, and can work at high frequency at the same cavity size. The dispersion relation of the structure is deduced theoretically and is confirmed by commercial software. The parameter dependences of dispersion relation are researched by computer simulations. According to previous theoretical work, the rectangle geometry is determined for EIO working at 0.1THzand 0.22THz respectively.3. Two kinds of electron guns are researched for the experiment. One is round beam electron gun, and another is sheet-beam electron gun. And two kinds of structures are studied. One is pierce structure; the other is parallel structure which focusing electrode is vartical with the sheet beam.4. The experiment of folded wave guide EIO working at 35GHz and 0.1THz has been done. The experiment results show which can be sdjusting by changing the voltage, the frequency region is between 35.4GHz and 35.5GHz, and the output power is 333W. The method of designing output window is given and the output window is designed and optimized for the experiment. The volt-ampere characteristic and temperature characteristic of the cathode have been measured by diode experiment.