Wave dispersion measurements of helically corrugated waveguides using a Vector Network Analyser
Lead Research Organisation:
University of Strathclyde
Department Name: Physics
Abstract
Gyrotron travelling wave amplifiers, oscillators and microwave pulse compressors based on helically corrugated waveguides have been developed at the University of Strathclyde at X-band Frequencies (8.2GHz to 12.4GHz). This proposal intends to study the use of helically corrugated waveguides to investigate the scalability of this concept to higher Ka-band (26.5GHz to 40GHz) and W-band (75GHz to 110GHz) frequencies. Two substantial problems immediately present themselves as one looks to increase the frequency, namely the requirements to fabricate an adequately accurate profile with a sufficiently smooth surface to produce the required dispersive properties with a tolerable loss. At the lower Xband frequencies hitherto investigated CNC mills have been used to produce the required 3D surface, but at higher frequencies the proportionately reduced tolerances plus the reduced clearances for tool access will prohibit this technique. The project will therefore investigate the alternative fabrication techniques available, including hydraulic and mechanical forming, electroforming, casting and spark erosion, all combined with electropolishing and thin surface plating. The fabricated waveguide sections will be measured by a Vector Network Analyser (VNA). The VNA will be used to measure the wave dispersion of helical structures by comparing the evolution of the principle value of the phase angle of the radiation as a function of frequency as it propagates through a known length of the waveguide. Measurements of the wave dispersion of amplifier and oscillator interaction regions and helical compressor sections will be benchmarked and compared with the predictions of theory and modelling.
Publications
Bratman V
(2010)
Generation of 3 GW microwave pulses in X-band from a combination of a relativistic backward-wave oscillator and a helical-waveguide compressor
in Physics of Plasmas
Bratman V
(2007)
Method for achievement of a multigigawatt peak power by compressing microwave pulses of a relativistic backward-wave oscillator in a helical waveguide
in Radiophysics and Quantum Electronics
Craig Roberston (Author)
(2010)
Simulations of Ka-band waveguide components for use in a gyro-travelling wave amplifier
Cross A
(2007)
Helically corrugated waveguide gyrotron traveling wave amplifier using a thermionic cathode electron gun
in Applied Physics Letters
He W
(2006)
Theory and simulations of a gyrotron backward wave oscillator using a helical interaction waveguide
in Applied Physics Letters
He W
(2008)
Axis-encircling electron beam generation using a smooth magnetic cusp for gyrodevices
in Applied Physics Letters
Liang Zhang
(2009)
Design of an Energy Recovery System for a Gyrotron Backward-Wave Oscillator
in IEEE Transactions on Plasma Science
| Description | It has been shown that by using a carefully designed helical waveguide two modes of wave propagation can be coupled together to provide a new synthesized mode of propagation. This result has been clearly demonstrated by theoretically designing such a helical waveguide and then measuring its dispersion using a Vector Network Analyser." |
| Exploitation Route | The novel helical waveguide can be used to construct high power microwave sources and to compress microwaves to higher peak powers. |
| Sectors | Aerospace, Defence and Marine,Electronics,Energy,Pharmaceuticals and Medical Biotechnology,Other |
| Description | Radiation sources and amplifiers, in the spectral region from microwave to terahertz, are extensively used in UK industry and public sectors such as security, defence, health and the environment. Companies, including e2v Technologies plc. (e2v) and TMD Technologies Ltd. (TMD), have developed and sold new radiation products based on post-1996 research undertaken at the University of Strathclyde. Their devices accessed new frequency ranges with considerable increases in power and bandwidth. The designs were transferred to industry, where devices have been constructed, jobs created, policy changed and considerable investments made. These sources have had extensive beneficial impact through applications in defence, surveillance, materials processing, health sciences and environmental monitoring. . The impact this would have is twofold. First, there is the obvious benefit to the environment, but second, the development and ultimate commercialisation of such technology would create wealth for the UK's economy. The current extraction process used by the mining industry involves passing rocks through a crusher to reduce them to a fine dust from which minerals and ore can be removed. However, this simple process comes at a high cost and uses an estimated 4% of the world's energy resources. This is where high-power magnetrons could make a big difference. When you put something unsuitable in your microwave, like a china cup, it tends to crack. If you do the same with rock, it also cracks, so that when you come to crush it, it just crumbles. High-power magnetrons would be used to pre-treat rocks with microwaves in order to reduce the amount of energy required to crush them. Funding provided by the EPSRC, under its Pathways to Impact programme, will help Adrian Cross and his team to reach their goal. The award will be used to initialise a collaboration with e2v Technologies, a UK-based company already manufacturing and selling world-class magnetron technology. "e2v is one of the companies in the UK that can exploit the technology that we are developing," explains Cross. "We want to provide impact by working with e2v, who have the market to sell these high-power magnetrons worldwide." Two members of the Strathclyde group are already working in tandem with e2v, thanks to the EPSRC's funding. The hope is that the collaboration will pool together the design expertise of the Cross group with the manufacturing capabilities of e2v to produce a truly world-leading high-power magnetron. . |
| First Year Of Impact | 2009 |
| Sector | Aerospace, Defence and Marine,Electronics,Energy,Pharmaceuticals and Medical Biotechnology,Other |
| Impact Types | Economic |
| Description | Research collaboration with Institute of Applied Physics, RAS |
| Organisation | Russian Academy of Sciences |
| Department | Institute of Applied Physics |
| Country | Russian Federation |
| Sector | Academic/University |
| PI Contribution | Host : Hosting academic visitor : Several visits of researchers from the Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia to Strathclyde University for research collaborations. |
| Start Year | 1995 |
| Description | Abdus Salam International Centre for Theoretical Physics College in Plasma Physics |
| Form Of Engagement Activity | Scientific meeting (conference/symposium etc.) |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Invited speaker : Participation in conference : Invited presentation at the Abdus Salam International Centre for Theoretical Physics College in Plasma Physics 10-28 August 2009, Trieste, Italy "Long wavelength free electron lasers: modelling and experiments" . Abdus Salam International Centre for Theoretical Physics College in Plasma Physics Requests from international students to come to the University of Strathclyde to study and research. |
| Year(s) Of Engagement Activity | 2009 |
| URL | http://www.ictp.tv/eya/plasma09.php |
| Description | Research collaboration with Institute of Applied Physics, RAS |
| Form Of Engagement Activity | Scientific meeting (conference/symposium etc.) |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Workshop Facilitator and Invited Keynote Speaker: International Scientific Workshops held in Russia in 2008, 2011 and 2014 Host : Hosting academic visitor : Several visits of researchers from the Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia to Strathclyde University for research collaborations. . Several collaborative research papers were published in international refereed journals. |
| Year(s) Of Engagement Activity | Pre-2006,2008,2011,2014 |
| Description | UK/Europe-China International Workshop |
| Form Of Engagement Activity | Scientific meeting (conference/symposium etc.) |
| Part Of Official Scheme? | No |
| Type Of Presentation | keynote/invited speaker |
| Geographic Reach | International |
| Primary Audience | Professional Practitioners |
| Results and Impact | Keynote/plenary speaker : Key-note speaker and plenary lectures at conferences : Invited keynote paper at UK/Europe-China International Workshop on millimetre-waves and terahertz technologies "Recent Progress in High Power Millimetre-wave Sources at Strathclyde University" 19-21 October 2009 , RAL, UK (Invited Keynote paper also given in the 1st Workshop held in Chengdu, China in 2008) . UK/Europe-China International Workshop Increased research collaborations with research groups in China and attraction of research students to the UK and to the University of Strathclyde. |
| Year(s) Of Engagement Activity | 2008,2009,2010,2011,2012,2013,2014 |
| URL | http://202.115.15.3/en/index/edit/pid/33 |