| Vacuum electronics is a traditional and new subject. Due to the appearance of new electromagnetic structures and materials, new ideas and inventions emerge in an endless stream, which makes the performance and reliability of the devices highly improved. In some important military and civil systems, high power and high frequency devices are indispensable and irreplaceable. More than 270 America military's military systems, such as radar, electronic warfare, and communication systems, have 185000 interfaces of vacuum electronic elements; in areas of aerospace, controlled thermonuclear fusion, high energy particle accelerator, etc, vacuum devices are also widely used; for civilian use like industrial heating systems, medical facilities and communication systems, vacuum electronic devices are important microwave sources; in the past decades, satellite digital communication technology's rapid development provided broad market for vacuum electronic devices, and shows great application prospects.The electric vacuum devices in millimeter wave band, for they works between millimeter band and infrared band, has the merits of wide absolute bandwidth, narrow beams, and being able to work in all weather, therefore, they have great potential application in radar, controlling and guiding, communication, electronic countermeasure, remote sensing and radiation measurement systems. But due to their small dimensions, traditional circular and annular electronic beams are not suitable to be the electronic sources, and new sources suitable for this kind of electronic devices become the hotspot and emphasis of current science research. After lots of researches, Many merits in electronic sheet beams have been found, for example, they can transfer heavy current within very little across dimensions, thus make the devices working in millimeter wave band produce high power; they can greatly decrease the space-charge effect, which is good for enlarge the interaction zone, thus decrease the demand of focusing system, as a result, it is very suitable to be the electronic source of the electric vacuum devices in millimeter wave band. Besides application in millimeter wave electric vacuum devices, electronic sheet beams are widely applied in accelerators, industrial material handling systems and biomedicine. The generation and stable transport of electronic sheet beams comes within the scope of many subjects, such as microwave electronics, plasma electronics, Electromagnetic Fields and Microwave Techniques, vacuum technique, materials science, which is a complex fundamental utility research problem. Intensive and painstaking study of these problems can not only promote our fundamental research level in vacuum electronics field and improve our independent innovation ability, which has important science meaning, but provides electronic sources greatly wanted in millimeter wave electric vacuum devices and accelerators, thus break western countries'blockade on new techniques, meet the urgent need of our country's martial and civil electronic systems, which has great practical significance.At present, there are two main ways to produce an electronic sheet beam,①direct approach: the sheet beam is produced directly by the sheet beam gun, which is divided into rectangle sheet beam gun and elliptical sheet beam gun.②indirect approach: the sheet beam are produced by circular beam flying through the asymmetric solenoid lenses. This article mainly describes the theory research and particle modeling of the first way.First in this article, the potential distribution expression of infinite planar diode is deduced, based on the theory of Pierce gun. Secondly, the rectangular electronic sheet beam or the elliptical electronic sheet beam is cut out from the planar diode, which boundary conditions are also determined in this step. Thirdly, the equipotential surface distribution expression outside the beam is deduced through the solution of the physical equation which the beam satisfied. At last, the shape of the electrode is confirmed through the solution of the equipotential surface distribution function.In this article, the generation of the rectangular electronic sheet beam and the elliptical electronic sheet beam are simulated in the particle model software. And factors affecting the beams'convergence property are found, which make the electronic sheet beam gun design easier.In the conclusion, comparison is made between the rectangular electronic sheet beam and the elliptical electronic sheet beam, and advantages and disadvantages of these two beams are given. |
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