NICOP - Compact high-power microwave oscillators
Abstract
Sources of microwave electromagnetic radiation are needed in many defense applications. Several ofthese applications require microwave oscillators that can achieve very high powers with good efficiency.A further highly desirable attribute is that of compactness. This proposal aims to design, construct andoperate a novel, compact, high-power microwave oscillator. An electron beam driven advanced form ofbackward wave oscillator (BWO) offers the realistic combination of very high power, with reasonably highefficiency in an exceptionally compact and low mass device.This proposal is based on some of our previous exploratory work of a novel compact S-band BWO,designed for operation in the TM01 mode (typical for conventional BWOs). A 2.5D Particle-in-Cell (PiC)code modelling study predicted output powers of 400MW for the S-band advanced compact BWO. In theexperimental study with pulse durations of 100ns, the prototype was observed to be able to operate alsoin the EH11 eigenmode. This potential to operate, efficiently, in either the EH11 or TM01 mode, providesinteresting and exciting challenges for further research and development and a potential solution to somecommon issues in high-power microwave defense applications.Based on this previous preliminary work at the University of Strathclyde at lower frequencies, a 3-yearnumerical and experimental research program is proposed to design, construct and measure the outoutfrom a novel, compact, high-power oscillator operating in the X-band (8 ??? 10GHz). This program is plannedto begin in Year 1 with a 2.5D numerical Particle-in-Cell (PiC) study to determine the general operationalparameter space, progressing to fully 3D numerical modelling to allow for simulation of the higher-ordermodes and azimuthal asymmetry. This would provide a more complete understanding of the mechanismsdetermining the mode of operation and the means of enhancing the efficiency. The experimental programwould construct a prototype based on the numerical modelling and seek to verify the predictedperformance by measurement of the output beginning towards the end of Year 2 and progressingthroughout Year 3.The potential for exploitation is increased by the anticipated significant reduction in the source size,weight, complexity and total energy requirements. The option to operate, efficiently, in the EH11 modewill be explored, as this mode may be advantageously transformed to the Gaussian-profile HE11 mode (orthe fundamental TE11 mode) without breaking the concentricity of the system. This allows for the launchof a well-defined, peaked-on-axis, radiated field pattern, while retaining the compact nature of the source.Alternatively, while operation in the TM01 mode incurs a requirement for an additional mode conversion,by necessity breaking concentricity of the central axis, the overall size and complexity of the source shouldstill be significantly reduced compared with a conventional BWO.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jul 27, 2018
- Source ID
- N629091812122
Entities
People
- Alan Phelps
Organizations
- Office of Naval Research
- United States Navy
- University of Strathclyde