Three-Dimensional Imaging Method Incorporating Range Points Migration and Doppler Velocity Estimation for UWB Millimeter-Wave Radar

High-resolution, short-range sensors that can be applied in optically challenging environments (e.g., in the presence of clouds, fog, and/or dark smog) are in high demand. Ultrawideband (UWB) millimeter-wave radars are one of the most promising devices for the above-mentioned applications. For target recognition using sensors, it is necessary to convert observational data into full 3-D images with both time efficiency and high accuracy. For such conversion algorithm, we have already proposed the range points migration (RPM) method. However, in the existence of multiple separated objects, this method suffers from inaccuracy and high computational cost due to dealing with many observed RPs. To address this issue, this letter introduces Doppler-based RPs clustering into the RPM method. The results from numerical simulations, assuming 140-GHz band millimeter radars, show that the addition of Doppler velocity into the RPM method results in more accurate 3-D images with reducing computational costs

Ultra-wideband radar and wireless human sensing

本論文では, 著者が近年開発してきたワイヤレス人体計測技術を紹介する. 超広帯域レーダを用いた人体イメージング技術では, 空港等の保安検査場で用いられるボディスキャナ装置への応用を想定し, 高速イメージングを実現するアルゴリズムを開発してきた. 人体のマイクロドップラ計測技術では, 乳幼児や高齢者の見守りサービスを想定し, 高速化と高分解能化を実現する信号処理技術を開発してきた. ワイヤレス非接触バイタル計測技術では, ヘルスケアや疾患のスクリーニングへの応用を想定し, 呼吸や心拍による皮膚の微小な変位をレーダにより計測するための高精度な非接触バイタル測定技術を開発してきた. これらの研究に共通するのは, 測定対象である人体についての事前知識を用いて電波センシングの性能を改善してきたという点である. こうした取り組みが今後の電波工学と生体医工学の融合への一助となることを期待する

Design of a high-power 48GHz gyroklystron amplifier for accelerator applications

As the technology of radiofrequency linear accelerators (RF linacs) continues to improve, higher frequency acceleration systems become of interest as the achievable acceleration gradient has a dependence on frequency. Using a high driving frequency requires the consideration of many technological challenges. One such challenge is mitigating the effect of nonlinearities introduced during the electron acceleration and bunching process. To counteract the nonlinearity, an additional cavity at a harmonic of the main driving frequency can be included. This technique is known as harmonic linearisation. In existing C-band systems, harmonic linearisation can be achieved with an X-band structure, but if the main frequency is X-band, the lineariser must be Ka-band or higher. Linear klystrons are a well-developed technology and can reliably deliver tens of MW at X-band, but they are subject to a steep drop-off in achievable output power toward the Ka-band. The different interaction mechanism in a gyroklystron, based on phase-modulation of a helical beam, allows it to deliver multi-MW output power at significantly higher frequencies. The gyroklystron is therefore a strong candidate for delivering power to high-frequency linearising cavities. The international collaboration, CompactLight, is developing a design for a sophisticated X-ray Free Electron Laser (XFEL) with wide ranging research applications [1, 2]. The project required the consideration of both a 36GHz and 48GHz lineariser options. In each case, the development of new amplifiers was required to deliver sufficient power for the application. This thesis presents the design and analysis of a gyroklystron appropriate to drive a 48GHz linearising cavity. While the research presented in this thesis was performed with direct consideration of the CompactLight XFEL, its relevance is not exclusive to this project. With the performance of the microwave amplifier presented in this thesis, a lineariser at 48GHz could be a viable option for other C-band or X-band accelerator applications. Gyroklystron research was historically focused on radar applications. Since 48GHz lies in a frequency band unfavourable for atmospheric transmission, the development of components in this band has been lacking. The design presented in this thesis is the first published work on a MW-level amplifier at 48GHz and marks a step toward this frequency becoming a desirable choice for linearisation systems in future linacs. A gyroklystron design, including the electron source, vacuum windows, and input coupler has been designed through detailed simulation work. A triode-type magnetron injection gun compatible with a 2.02T axial guide magnetic field was designed and simulated. Applying -140kV to the cathode and -107.5kV to the modulating anode resulted in a gyrating electron beam with a current of 37A, guiding centre radius of 1.77mm, and velocity ratio spread of 8.9%. This resulted in a predicted gyroklystron output power of 2.0MW with a gain of 35dB at an efficiency of 38.6%.As the technology of radiofrequency linear accelerators (RF linacs) continues to improve, higher frequency acceleration systems become of interest as the achievable acceleration gradient has a dependence on frequency. Using a high driving frequency requires the consideration of many technological challenges. One such challenge is mitigating the effect of nonlinearities introduced during the electron acceleration and bunching process. To counteract the nonlinearity, an additional cavity at a harmonic of the main driving frequency can be included. This technique is known as harmonic linearisation. In existing C-band systems, harmonic linearisation can be achieved with an X-band structure, but if the main frequency is X-band, the lineariser must be Ka-band or higher. Linear klystrons are a well-developed technology and can reliably deliver tens of MW at X-band, but they are subject to a steep drop-off in achievable output power toward the Ka-band. The different interaction mechanism in a gyroklystron, based on phase-modulation of a helical beam, allows it to deliver multi-MW output power at significantly higher frequencies. The gyroklystron is therefore a strong candidate for delivering power to high-frequency linearising cavities. The international collaboration, CompactLight, is developing a design for a sophisticated X-ray Free Electron Laser (XFEL) with wide ranging research applications [1, 2]. The project required the consideration of both a 36GHz and 48GHz lineariser options. In each case, the development of new amplifiers was required to deliver sufficient power for the application. This thesis presents the design and analysis of a gyroklystron appropriate to drive a 48GHz linearising cavity. While the research presented in this thesis was performed with direct consideration of the CompactLight XFEL, its relevance is not exclusive to this project. With the performance of the microwave amplifier presented in this thesis, a lineariser at 48GHz could be a viable option for other C-band or X-band accelerator applications. Gyroklystron research was historically focused on radar applications. Since 48GHz lies in a frequency band unfavourable for atmospheric transmission, the development of components in this band has been lacking. The design presented in this thesis is the first published work on a MW-level amplifier at 48GHz and marks a step toward this frequency becoming a desirable choice for linearisation systems in future linacs. A gyroklystron design, including the electron source, vacuum windows, and input coupler has been designed through detailed simulation work. A triode-type magnetron injection gun compatible with a 2.02T axial guide magnetic field was designed and simulated. Applying -140kV to the cathode and -107.5kV to the modulating anode resulted in a gyrating electron beam with a current of 37A, guiding centre radius of 1.77mm, and velocity ratio spread of 8.9%. This resulted in a predicted gyroklystron output power of 2.0MW with a gain of 35dB at an efficiency of 38.6%

Low-THz Automotive 3D Imaging Radar

This thesis lays out initial investigations into the 3D imaging capabilities of low-THz radar for automotive applications. This includes a discussion of the state of the art of automotive sensors, and the need for a robust, high-resolution imaging system to compliment and address the short-comings of these sensors. The unique capabilities of low-THz radar may prove to be well-suited to meet these needs, but they require 3D imaging algorithms which can exploit these capabilities effectively. One such unique feature is the extremely wide signal bandwidth, which yields a fine range resolution. This is a feature of low-THz radar which has not been discussed or properly investigated before, particularly in the context of generating the 3D position of an object from range information. The progress and experimental verification of these algorithms with a prototype multi-receiver 300GHz radar throughout this project are described; progressing from simple position estimation to highly detailed 3D radar imaging. The system is tested in a variety of different scenarios which a vehicle must be able to navigate, and the 3D imaging radar is compared with current automotive demonstrators experimentally

Third National Aeronautics and Space Administration Weather and climate program science review

Research results of developing experimental and prototype operational systems, sensors, and space facilities for monitoring, and understanding the atmosphere are reported. Major aspects include: (1) detection, monitoring, and prediction of severe storms; (2) improvement of global forecasting; and (3) monitoring and prediction of climate change

Earth orbital experiment program and requirements study, volume 1, sections 1 - 6

A reference manual for planners of manned earth-orbital research activity is presented. The manual serves as a systems approach to experiment and mission planning based on an integrated consideration of candidate research programs and the appropriate vehicle, mission, and technology development requirements. Long range goals and objectives for NASA activities during the 1970 to 1980 time period are analyzed. The useful and proper roles of manned and automated spacecraft for implementing NASA experiments are described. An integrated consideration of NASA long range goals and objectives, the system and mission requirements, and the alternative implementation plans are developed. Specific areas of investigation are: (1) manned space flight requirements, (2) space biology, (3) spaceborne astronomy, (4) space communications and navigation, (5) earth observation, (6) supporting technology development requirements, (7) data management system matrices, (8) instrumentation matrices, and (9) biotechnology laboratory experiments

Advances in Optical Amplifiers

Optical amplifiers play a central role in all categories of fibre communications systems and networks. By compensating for the losses exerted by the transmission medium and the components through which the signals pass, they reduce the need for expensive and slow optical-electrical-optical conversion. The photonic gain media, which are normally based on glass- or semiconductor-based waveguides, can amplify many high speed wavelength division multiplexed channels simultaneously. Recent research has also concentrated on wavelength conversion, switching, demultiplexing in the time domain and other enhanced functions. Advances in Optical Amplifiers presents up to date results on amplifier performance, along with explanations of their relevance, from leading researchers in the field. Its chapters cover amplifiers based on rare earth doped fibres and waveguides, stimulated Raman scattering, nonlinear parametric processes and semiconductor media. Wavelength conversion and other enhanced signal processing functions are also considered in depth. This book is targeted at research, development and design engineers from teams in manufacturing industry, academia and telecommunications service operators

Preclinical MRI of the kidney : methods and protocols

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers

Nuclear Fusion Programme: Annual Report of the Association Karlsruhe Institute of Technology/EURATOM ; January 2011 - December 2011 (KIT Scientific Reports ; 7621)

The Karlsruhe Institute of Technology (KIT) is working in the framework of the European Fusion Programme on key technologies in the areas of superconducting magnets, microwave heating systems (Electron-Cyclotron-Resonance-Heating, ECRH), the deuterium-tritium fuel cycle, He-cooled breeding blankets, a He-cooled divertor and structural materials, as well as refractory metals for high heat flux applications including a major participation in the preparation of the international IFMIF project