Harmonic and higher order mode mm-wave klystrons

谐波和高阶模毫米波速调管

• 批准号: ST/K002953/1
• 负责人: Graeme Burt
• 金额: $ 5.58万
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FK002953%2F1
• 关键词: Harmonic; higher; order; mode; mm

The Klystron is a well-known, high efficiency amplifier, with a simple structure and scalable dimensions. It is typically designed with cylindrical reentrant cavities in the fundamental mode. However as the frequency of the device increases the size of the structure decreases. At mm-wave frequencies this leads to two problems: 1) Manufacturing the complex small scale structures. 2) The gap voltage decreases as the gap gets shorter leading to less gain.Most mm-wave klystron concepts reported in the literature are simply smaller versions of microwave klystrons. Even if, in principle the dimensions can be scaled according to the frequency increase, the fabrication challenges and the beam characteristic represent a huge obstacle to the realization of a working device when frequency is higher than 50 GHz. This is consequently true for the frequency range around 94 GHz, which is of great interest for communication and radar applications.This proposal is aimed to overcome of the above-mentioned obstacle to the design and realization of a 94 GHz klystron by two innovative design solutions. The first solution is to operate the cavity at a higher order mode, chosen with similar Ez field distribution on the gap cross-section as the fundamental mode. The design will adopt reentrant cavities with square or rectangular shape, to be compatible with a photolithographic fabrication technique. The higher mode operation permits to design the cavities with dimensions larger (at least 4 -5 times) than in case of fundamental mode operation. This eases the technological effort and makes possible a high quality fabrication by mechanical micromachining or by photolithographic processes. Further, the beam tunnel can be larger than in fundamental mode, to support higher beam current. In order to increase the interaction a number of intermediate buncher cavities, spaced all along the drift tube, will be used to increase the beam current modulation.A separate approach uses a lower frequency input cavity to modulate the beam current. As the beam travels down the drift tube beam harmonics start to form hence a higher order mode output cavity at an integer harmonic frequency of the input cavity can be exited hence acting as a high power frequency multiplier. As the input can be a readily available high power microwave source we are able to overcome the low gain of the device.

Klystron是一个众所周知的高效率放大器，具有简单的结构和可扩展的尺寸。它通常在基本模式下使用圆柱恢复腔设计。但是，随着设备的频率，结构的尺寸增加了。在MM波频率上，这导致了两个问题：1）制造复杂的小规模结构。 2）随着差距的变短，差距的电压降低了，导致增益较小。文献中报道的大多数MM-Wave Klystron概念只是微波klystron的较小版本。即使原则上可以根据频率增加来缩放尺寸，当频率高于50 GHz时，制造挑战和梁特性代表了实现工作设备的巨大障碍。因此，对于94 GHz左右的频率范围是正确的，这对于通信和雷达应用引起了极大的兴趣。该提案的目的是克服上述障碍，以通过两种创新的设计解决方案来设计和实现94 GHz Klystron。第一个解决方案是在较高阶模式下操作腔，在间隙横截面上与基本模式相似的EZ场分布选择。该设计将采用具有正方形或矩形形状的重入腔，与光刻制造技术兼容。较高的模式操作允许与基本模式操作更大的尺寸（至少4-5倍）设计空腔。这可以减轻技术的努力，并通过机械微机械或光刻过程使高质量的制造成为可能。此外，梁隧道可以比基本模式大，以支撑更高的光束电流。为了增加相互作用，将使用沿漂移管间隔的许多中间束腔，以增加光束电流调制。一种单独的方法使用较低的频率输入腔来调节束电流。随着光束向下行驶，漂移管梁谐波开始形成，因此可以将输入腔的整数谐波频率下的高阶模式输出腔，因此可以充当高功率频率乘数。由于输入可以是一个容易获得的高功率微波源，因此我们能够克服设备的低增益。

项目成果

2-D particle-in-cell simulations of high efficiency klystrons

高效速调管的二维细胞内粒子模拟

• DOI: 10.1109/ivec.2016.7561813
• 发表时间: 2016
• 作者: Constable D

Ka-band linearizer structure studies for a compact light source

紧凑型光源的 Ka 波段线性化器结构研究

• DOI: 10.1103/physrevaccelbeams.25.112001
• 发表时间: 2022
• 期刊: Physical Review Accelerators and Beams
• 影响因子: 1.7
• 作者: Castilla A