High power mm and sub-mm wave amplifiers for high frequency ESR/DNP, high resolution radar and remote sensing

在回旋管中，在磁场中回旋的电子以这样的方式耦合到电磁辐射，即通过提取电子动能来放大辐射。我们将研究一种新的概念，它使用一个螺旋形的“圆柱形”波导的内表面上从根本上修改波的色散，使本征模有限，恒定的群速度在该地区的近无限的相速度。这种新颖的色散首次为在90 GHz至100 GHz及以上频率范围内的高功率（5 kW）、宽带（10%）、高增益> 40 dB、效率（30%）回旋管放大器开辟了潜力。我们已经在X波段（8 GHz至10 GHz）频率进行了初步实验，并将在我们的领导下，基于对这一新概念的最佳理解，在W波段（90 GHz至100 GHz）频段创建一个放大器，并对其增益，带宽，效率和振荡稳定性进行精确测量。以W波段实验数据为基准的新理论和计算模型将用于证明这种新型放大器产生许多已知应用所急需的高频（360 GHz至400 GHz和460 GHz至500 GHz）、高功率（~ 0.5 kW）、宽带（10%）、脉冲和连续相干辐射的潜力。

In a gyrotron, electrons gyrating in a magnetic field are coupled to electromagnetic radiation in such a manner that the radiation is amplified by extracting the electron kinetic energy. We will investigate a novel concept which uses a helical corrugation on the inside surface of a 'cylindrical' waveguide to radically modify the wave dispersion giving eigenmodes with finite, constant group velocity in the region of near infinite phase velocity. This novel dispersion opens up for the first time the potential for a high power (5kW), broadband (10%), high gain >40dB, efficient (30%) gyrotron amplifier in the 90GHz to 100GHz frequency range and above. We have performed a preliminary experiment at X-band (8GHz to 10GHz) frequencies and will build on our lead to create an amplifier in the W-band (90GHz to 100GHz) frequency band based on the best understanding of this new concept and perform precision measurements of its gain, bandwidth, efficiency and stability against oscillations. New theory and computational models benchmarked against W-band experimental data will be used to demonstrate the potential for this novel amplifier to generate high frequency (360GHz to 400GHz and 460GHz to 500GHz), high power (~0.5kW), broadband (10%), pulsed and continuous coherent radiation crucially needed by the many known applications.