A High Voltage Pulsed Power Modulator For Fast Rising Arbitrary Waveforms

Magnetic fusion is one approach to generate thermonuclear fusion power in an environmental friendly way. The Electron Cyclotron Resonance Heating is considered as the major concept for startup, heating and control of the fusion plasma. Megawatt-class gyrotrons generate the required microwave power. This work focuses on advanced key components and technologies for a DEMO relevant 2 MW gyrotron. One major focus is on the development of advanced Magnetron Injection Guns. Another focus is on the red

Microwave-assisted alkaline hydrolysis of PET can be 20 times faster and at lower temperatures. This work presents a novel industrial microwave applicator at 2.45 GHz with homogeneous distribution to support this reaction, which allows an efficient and continuous operation. In addition, an innovative dielectric and calorimetric measurements setup is presented. Furthermore, the modelling of the reaction kinetics based on the measured dielectric parameters is presented.

This work presents the development of a new sub-THz source for the generation of trains of coherent high-power ultra-short pulses at 263 GHz via passive mode-locking of two coupled helical gyro-TWTs. For the first time, it is shown that the operation of such passive mode-locked helical gyro-TWTs in the hard excitation regime is of particular importance to reach the optimal coherency of the generated pulses. This could be of particular interest for some new time-domain DNP-NMR methods.

Ein Gyrotron wird in magnetisch eingeschlossenen Plasmaexperimenten für Heizung, Stromtrieb, Plasmastabilisierung und Plasmadiagnostik verwendet. In dieser Arbeit wird der erste Entwurf und Bau eines Mehrfrequenz-/Mehrzweck Pre-Prototyp Gyrotrons in koaxialer Technologie vorgestellt, das bei (136)/170/204 GHz mit einer Ausgangsleistung von 2 MW arbeitet. Dies ist der erste Schritt zum Betrieb bei Frequenzen bis zu 240 GHz unter Verwendung der Koaxialhohlraum-Gyrotrontechnologie. - A gyrotron is used in magnetically confined plasma experiments for heating, current drive, plasma stabilization and plasma diagnostics. This work presents the first design and construction of a multi-frequency / multi-purpose coaxial-cavity pre-prototype gyrotron operating at (136)/170/204 GHz with an output power of 2 MW. It is the first step towards operating frequencies up to 240 GHz using the coaxial-cavity gyrotron technology.

Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-frequency systems. The book features contributions by leading international researchers, many of whom are pioneers in the field. They examine wave generation, measurement, detection, control, and propagation in detail, as well as the devices and components that enable ultrawide-band and ultrafast transmission, switching, and signal processing. These devices and components include optical-controlled microwave devices, optical transmitters, receivers, switching devices, detectors, and modulators. The book explores the theory, techniques, and technologies that are fueling applications such as radio-over-fiber, injection-locked semiconductor lasers, and terahertz photonics. Throughout, the contributors share insights on overcoming current limitations and on potential developments. What’s New in This Edition Two new chapters, on fiber Bragg gratings for microwave photonics applications and ultrawide-band sub-THz photonic wireless links Updates throughout, reflecting advances in the field New illustrations in each chapter Fully illustrated with more than 300 figures and tables, this book offers a detailed, wide-ranging overview of the current state and future directions of this burgeoning technology.

This book presents a variety of techniques using high-frequency (RF) and time-domain measurements to understand the electrical performance of novel, modern transistors made of materials such as graphene, carbon nanotubes, and silicon-on-insulator, and using new transistor structures. The author explains how to use conventional RF and time- domain measurements to characterize the performance of the transistors. In addition, he explains how novel transistors may be subject to effects such as self-heating, period-dependent output, non-linearity, susceptibility to short-term degradation, DC-invisible structural defects, and a different response to DC and transient inputs. Readers will understand that in order to fully understand and characterize the behavior of a novel transistor, there is an arsenal of dynamic techniques available. In addition to abstract concepts, the reader will learn of practical tips required to achieve meaningful measurements, and will understand the relationship between these measurements and traditional, conventional DC characteristics.

The rapid proliferation of the Internet has been driving communication networks closer and closer to their limits, while available bandwidth is disappearing due to an ever-increasing network load. Over the past decade, optical fiber communication technology has increased per fiber data rate from 10 Tb/s to exceeding 10 Pb/s. The major explosion came after the maturity of coherent detection and advanced digital signal processing (DSP). DSP has played a critical role in accommodating channel impairments mitigation, enabling advanced modulation formats for spectral efficiency transmission and realizing flexible bandwidth. This book aims to explore novel, advanced DSP techniques to enable multi-Tb/s/channel optical transmission to address pressing bandwidth and power-efficiency demands. It provides state-of-the-art advances and future perspectives of DSP as well.