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Journal articles on the topic 'Pulse microwave generator'

Author: Grafiati

Published: 4 June 2021

Last updated: 11 February 2022

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1

Liu, Sheng, Jian-Cang Su, Xibo Zhang, Ya-Feng Pan, Hong-Yan Fan, and Xu-Liang Fan. "A Tesla-type long-pulse generator with wide flat-top width based on a double-width pulse-forming line." Laser and Particle Beams 36, no. 1 (March 2018): 115–20. http://dx.doi.org/10.1017/s0263034618000034.

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AbstractTo produce pulses with good flat-top quality, pulse-forming lines (PFLs) have been widely used in the field of Tesla-type pulse generators. To shorten the physical length of the PFL, a double-width PFL (DWPFL) is proposed that doubles the output pulse width while maintaining flat-top quality. A repetitively 10 GW Tesla-type long-pulse generator producing pulses with flat-top width of about 110 ns was developed with a coaxial DWPFL to produce high-current electron beams. Electron beams of about 10 GW with flat-top widths of about 110 ns were obtained on a planar vacuum diode load. With this pulse generator and a C-band high-power microwave system, microwaves of ~2.2 GW power and full-width at half-maximum of 101 ns were generated. The experiment demonstrates the feasibility and ideal output waveform quality of the DWPFL.

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2

Zherlitsyn, A. G., L. D. Butakov, V. S. Kositsyn, V. I. Tolmachev, and V. P. Shiyan. "A pulse microwave generator." Instruments and Experimental Techniques 55, no. 3 (May 2012): 389–91. http://dx.doi.org/10.1134/s0020441212020182.

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3

White, G. O., L. Chen, C. E. Patton, and R. L. Tinkoff. "High‐power microwave pulse generator." Review of Scientific Instruments 63, no. 5 (May 1992): 3156–66. http://dx.doi.org/10.1063/1.1142569.

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4

Riaziat, M. L., and C. K. Nishimoto. "Compact optically triggered microwave pulse generator." Microwave and Optical Technology Letters 5, no. 5 (May 1992): 211–15. http://dx.doi.org/10.1002/mop.4650050503.

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5

Mohamed, M. M., T. Uchida, and S. Minami. "A Pulse-Operated Microwave-Induced Plasma Source." Applied Spectroscopy 43, no. 1 (January 1989): 129–34. http://dx.doi.org/10.1366/0003702894202058.

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A new pulse-operated microwave-induced plasma (MIP) source is described. To avoid operational difficulties of the MIP due to Joule heating and to obtain spectral emission lines of high peak intensities, one energizes the MIP source with a TM010 cavity with a microwave pulse of large peak power and short duration, which is superposed on a low-bias dc microwave. A peak power of 400 W, which is two times the maximum output ratings of a magnetron under a normal dc operation, can be generated by applying a −500 V pulse to the cathode of the magnetron operating under the bias mode. The pulsed-MIP requires no special cooling system since the mean power remains low during the entire operation. Some of the considerations taken into account in the design and construction of the microwave generator are presented. The electrical and spectral characteristics of the MIP source are also described in detail.

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6

Zhang, Haoran, Ting Shu, Shifei Liu, Zicheng Zhang, Lili Song, and Heng Zhang. "A Compact Modular 5 GW Pulse PFN-Marx Generator for Driving HPM Source." Electronics 10, no. 5 (February 26, 2021): 545. http://dx.doi.org/10.3390/electronics10050545.

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A compact and modular pulse forming network (PFN)-Marx generator with output parameters of 5 GW, 500 kV, and 30 Hz repetition is designed and constructed to produce intense electron beams for the purpose of high-power microwave (HPM) generation in the paper. The PFN-Marx is composed by 22 stages of PFN modules, and each module is formed by three mica capacitors (6 nF/50 kV) connected in parallel. Benefiting from the utilization of mica capacitors with high energy density and a mini-trigger source integrated into the magnetic transformer and the magnetic switch, the compactness of the PFN-Marx system is improved significantly. The structure of the PFN module, the gas switch unit, and the connection between PFN modules and switches are well designed for modular realization. Experimental results show that this generator can deliver electrical pulses with the pulse width of 100 ns and amplitude of 500 kV on a 59-ohm water load at a repetition rate of 30 Hz in burst mode. The PFN-Marx generator is fitted into a cuboid stainless steel case with the length of 80 cm. The ratio of storage energy to volume and the ratio of power to weight of the PFN-Marx generator are calculated to be 6.5 J/L and 90 MW/kg, respectively. Furthermore, utilizing the generator to drive the transit time oscillator (TTO) at a voltage level of 450 kV, a 100 MW microwave pulse with the pulse width of 20 ns is generated.

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7

Volkov, Aleksey A. "Parameters of the electric strength of air in a surface antenna during the emission of an ultrahigh-frequency pulse with a trapezoidal envelope." Physics of Wave Processes and Radio Systems 23, no. 3 (December 27, 2020): 62–67. http://dx.doi.org/10.18469/1810-3189.2020.23.3.62-67.

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On the basis of the breakdown criterion and the equation of continuity of electrons in air, the amplitude and energy parameters of the electric strength of air in the surface antenna of a powerful microwave relativistic generator are determined when pulses are emitted with a trapezoidal envelope. Triangular and rectangular envelopes were considered as boundary cases of a trapezoidal envelope. The dependence of the parameters of electric strength on the shape of the envelope has been established. The calculation of the dependences of the breakdown field and the maximum permissible energy in a flat aperture on the pulse duration in the range of realizable durations of powerful relativistic microwave generators is carried out. For the same duration, the largest breakdown field has a pulse with a triangular envelope, and the smallest a pulse with a rectangular envelope. Wherein a pulse with a triangular envelope has the lowest maximum permissible energy, and a rectangular one has the highest. The relationships between the maximum permissible energy and the breakdown field for the pulses under consideration are determined. With the same maximum permissible peak amplitude, the highest energy has a pulse with a triangular envelope, and the smallest a pulse with a rectangular envelope.

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8

Ahajjam, Y., O. Aghzout, J. M. Catala-Civera, F. Peñaranda-Foix, and A. Driouach. "An Accurate and Compact High Power Monocycle Pulse Transmitter for Microwave Ultra-Wideband Radar Sensors with an enhanced SRD model: Applications for Distance Measurement for lossy materials." Advanced Electromagnetics 8, no. 3 (September 5, 2019): 76–82. http://dx.doi.org/10.7716/aem.v8i3.676.

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In This paper, a high power sub-nanosecond pulse transmitter for Ultra-wideband radar sensor is presented. The backbone of the generator is considered as a step recovery diode and unique pulse injected into the circuit, which gives rise to an ultra-wide band Gaussian pulse. The transistor driver and transmission line pulse forming the whole network are investigated in detail. The main purpose of this work is to transform a square waveform signal to a driving pulse with the timing and the amplitude parameters required by the SRD to form an output Gaussian pulse, and then into high monocycle pulses. In simulation aspect, an improved output response is required, in this way a new model of step recovery diode has been proposed as a sharpener circuit. This proposition was applied to increase the rise-time of the pulses. For a good range radar, a high amplitude pulse is indispensable, especially when it comes to penetrate thick lossy materiel. In order to overcome this challenge, a simple technique and useful solution is introduced to increase the output amplitude of the transmitter. This technique consists to connect the outputs of two identical pulse generators in parallel respecting the restrictions required. The pulse transmitter circuit is completely fabricated using micro-strip structure technology characteristics. Waveforms of the generated monocycle pulses over 10V in amplitude with 3.5 % in overshoot have been obtained. Good agreement has been achieved between measurement and simulation results.

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9

Minamitani, Yasushi, Yoshinori Ohe, and Yoshio Higashiyama. "Nanosecond High Voltage Pulse Generator Using Water Gap Switch for Compact High Power Pulsed Microwave Generator." IEEE Transactions on Dielectrics and Electrical Insulation 14, no. 4 (August 2007): 894–99. http://dx.doi.org/10.1109/tdei.2007.4286522.

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10

Pinguet, Sylvain, Jean-Pierre Duperoux, Philippe Delmote, Francois Bieth, and Rainer Bischoff. "Short-Pulse Marx Generator for High-Power Microwave Applications." IEEE Transactions on Plasma Science 41, no. 10 (October 2013): 2754–57. http://dx.doi.org/10.1109/tps.2013.2277981.

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11

Xie, Yifang, and Weiming Xiong. "Truly balanced pulse generator using microwave transistor and SRD." Journal of Electronics (China) 28, no. 1 (January 2011): 141–44. http://dx.doi.org/10.1007/s11767-011-0607-8.

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12

Li, Mingjia, Qiang Kang, Jie Tan, Min Luo, and Fei Xiang. "A High-Power Pulse Generator Based on Pulse Forming Network and Linear Transformer." Laser and Particle Beams 2021 (January 28, 2021): 1–8. http://dx.doi.org/10.1155/2021/6686530.

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With the development of high-power microwave technology, the output power of the pulse generator is required more and more higher. In this paper, it is realized by increasing the output power of the module while the output impedance of the module changes little. The module of the generator is based on pulse forming network (PFN) and linear transformer (LT). Four Blumlein PFNs with arc-type configuration and 24 Ω characteristic impedance were connected symmetrically to the primary coil of the LTD and driven by two identical laser triggered spark switches to ensure four Blumlein PFNs synchronizing operation. On this basis, a two-stage high-power pulse generator based on PFN-LT is developed. The following technical parameters of the generator were achieved on a 12 Ω high-power solid resistor: output voltage amplitude of ∼250 kV and output power of ∼5.2 GW at a repetition rate of 5 Hz.

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13

Ernyleva, S. E., I. L. Bogdankevich, and O. T. Loza. "Mechanism of radiation pulse shortening in plasma relativistic microwave generator." Bulletin of the Lebedev Physics Institute 40, no. 7 (July 2013): 178–86. http://dx.doi.org/10.3103/s1068335613070026.

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14

Zhu, Sha, Mengxiang Gao, Ming Li, Ning Hua Zhu, and Wei Li. "A background-free phase-coded microwave pulse generator by optoelectronic oscillation." Optics Communications 453 (December 2019): 124318. http://dx.doi.org/10.1016/j.optcom.2019.124318.

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15

Savchenkov, A. A., A. B. Matsko, and L. Maleki. "On Frequency Combs in Monolithic Resonators." Nanophotonics 5, no. 2 (June 1, 2016): 363–91. http://dx.doi.org/10.1515/nanoph-2016-0031.

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AbstractOptical frequency combs have become indispensable in astronomical measurements, biological fingerprinting, optical metrology, and radio frequency photonic signal generation. Recently demonstrated microring resonator-based Kerr frequency combs point the way towards chip scale optical frequency comb generator retaining major properties of the lab scale devices. This technique is promising for integrated miniature radiofrequency and microwave sources, atomic clocks, optical references and femtosecond pulse generators. Here we present Kerr frequency comb development in a historical perspective emphasizing its similarities and differences with other physical phenomena. We elucidate fundamental principles and describe practical implementations of Kerr comb oscillators, highlighting associated solved and unsolved problems.

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16

Roy, Amitava, R. Menon, Vishnu Sharma, Ankur Patel, Archana Sharma, and D. P. Chakravarthy. "Features of 200 kV, 300 ns reflex triode vircator operation for different explosive emission cathodes." Laser and Particle Beams 31, no. 1 (November 27, 2012): 45–54. http://dx.doi.org/10.1017/s026303461200095x.

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AbstractTo study the effect of explosive field emission cathodes on high power microwave generation, experiments were conducted on a reflex triode virtual cathode oscillator. Experimental results with cathodes made of graphite, stainless steel nails, and carbon fiber (needle type) are presented. The experiments have been performed at the 1 kJ Marx generator (200 kV, 300 ns, and 9 kA). The experimentally obtained electron beam diode perveance has been compared with the one-dimensional Child-Langmuir law. The cathode plasma expansion velocity has been calculated from the perveance data. It was found that the carbon fiber cathode has the lowest cathode plasma expansion velocity of 1.7 cm/μs. The radiated high power microwave has maximum field strength and pulse duration for the graphite cathode. It was found that the reflex triode virtual cathode oscillator radiates a single microwave frequency with the multiple needle cathodes for a shorter (<200 ns full width at half maximum) voltage pulse duration.

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17

Ahajjam, Younes, Otman Aghzout, José M. Catala-Civera, Felipe Peñaranda-Foix, and Abdellah Driouach. "New Generator Design with Enhanced Output Waveform for Non-Destructive Radar Sensor Measurements." MATEC Web of Conferences 191 (2018): 00002. http://dx.doi.org/10.1051/matecconf/201819100002.

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In this paper, a high power UWB monocycle generator for Non-Destructive Microwave Radar-Sensor detection is presented. The full radar system is compound with a designed UWB generator, two commercial antennas, and an oscilloscope as a receptor. The generator is composed of three essential parts-circuits, an avalanche transistor, an SRD pulse sharping and an MFN. The main idea in this work is to convert the square waveform to a driving pulse with the parameters required by the SRD pulse sharpening to obtain an output Gaussian pulse. This output pulse is converted then into a monocycle pulse. As we know, for a good range radar measurement, a high amplitude of pulse with a minimum ringing is indispensable, especially when the measurements requires many accuracies. In order to increase the pulse of the transmitter, a useful technique has been introduced; this technique consists of making the discharge path as short as possible. The applicant technique leads also to minimize the ringing in the output pulse. The measurements had been carrying out in an anechoic chamber, with the distance between 50 and 270 cm. Good Agreements between the measured and calculated results are achieved, therefore, this system can be considered very attractive in many application fields.

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18

Zhang, Haoran, Ting Shu, Zhiqiang Li, Zicheng Zhang, Wei Li, and Da Li. "A compact 4 GW pulse generator based on pulse forming network-Marx for high-power microwave application." Review of Scientific Instruments 92, no. 6 (June 1, 2021): 064707. http://dx.doi.org/10.1063/5.0040111.

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19

Pongrac, Blaž, Denis Đonlagic, Matej Njegovec, and Dušan Gleich. "THz Signal Generator Using a Single DFB Laser Diode and the Unbalanced Optical Fiber Interferometer." Sensors 20, no. 17 (August 28, 2020): 4862. http://dx.doi.org/10.3390/s20174862.

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This paper presents a frequency-modulated optical signal generator in the THz band. The proposed method is based on a fast optical frequency sweep of a single narrowband laser diode used together with an optical fiber interferometer. The optical frequency sweep using a single laser diode is achieved by generating short current pulses with a high amplitude, which are driving the laser diode. Theoretical analysis showed that the modulation frequency could be changed by the optical path difference of the interferometer or optical frequency sweep rate of a laser diode. The efficiency of the optical signal generator with Michelson and Fabry–Perot interferometers is theoretically analyzed and experimentally evaluated for three different scenarios. Interferometers with different optical path differences and a fixed optical frequency sweep rate were used in the first scenario. Different optical frequency sweep rates and fixed optical path differences of the interferometers were used in the second scenario. This paper presents a method for optical chirp generation using a programmable current pulse waveform, which drives a laser diode to achieve nonlinear optical sweep with a fixed optical path difference of the interferometer. The experimental results showed that the proposed signals could be generated within a microwave (1–30 GHz) and THz band (0.1–0.3 THz).

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20

Karushkin, N. F. "Synchronization of pulsed and continuous-wave IMPATT oscillators in the millimeter wavelength range. Part 1. Generator designs and a generalized model of their external signal synchronization." Технология и конструирование в электронной аппаратуре, no. 1-2 (2021): 10–20. http://dx.doi.org/10.15222/tkea2021.1-2.10.

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Advances in the development of ultrahigh-frequency semiconductor electronics open wide opportunities for developing optimal schemes and designs of microwave power sources in the millimeter wavelength range providing high stability of the frequency and electromagnetic oscillation phase. Synchronized diode generators used in transmit/receive module for active phased array antennas, coherent low-power radar stations, etc. show great promise. The mode of external synchronization of semiconductor generators allows effectively implementing the task of creating output stages of the transmitters with high gain factor, low frequency noise and an output power level corresponding to the maximum power mode. This article presents the first of two parts of the study, which summarizes the results achieved so far in the development of synchronized oscillators based on impact ionization avalanche transit-time (IMPATT) diodes. The first part presents the electrodynamic designs of the oscillators, which are synchronized with an external source of microwave oscillations and contain a resonant oscillating system with a silicon IMPATT diode. The silicon two-drift IMPATT diode was chosen as an active element due to the fact that its use allows reaching significant levels of pulsed microwave power – an order of magnitude higher than those of the most well-known HEMT and pHEMT transistors in the millimeter wavelength range. It is shown that to reduce losses, the oscillating system should be made in the form of a radial resonator with a diode casing, which has distributed parameters. This eliminates the use of additional reactive inhomogeneities in the initial cross-section of the waveguide section of the generator. Due to the low quality factor of the resonant casing of the diode, the generalized quality factor of the microwave circuit takes the minimum value required to implement a stable generator synchronization process in the millimeter wavelength range. The second part of the work will be devoted to synchronized pulse generators with an output power of 20–150 W.

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21

Jeong Soo Lee, C. Nguyen, and T. Scullion. "New uniplanar subnanosecond monocycle pulse generator and transformer for time-domain microwave applications." IEEE Transactions on Microwave Theory and Techniques 49, no. 6 (June 2001): 1126–29. http://dx.doi.org/10.1109/22.925501.

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22

Titov, A. A., V. P. Pushkarev, D. Yu Pelyavin, and I. V. Shukhlov. "A pulse microwave generator for short-range radar-location and radio navigation systems." Instruments and Experimental Techniques 54, no. 5 (September 2011): 705–8. http://dx.doi.org/10.1134/s0020441211050162.

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23

Banjac, Goran, Vladimir Đorđević, Miladin Živković, and Abdellah Ferdjali. "High energy microwave weapon: Electromagnetic bomb." Vojnotehnicki glasnik 69, no. 2 (2021): 499–517. http://dx.doi.org/10.5937/vojtehg69-29007.

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Introduction/purpose: Technological progress has led to the actualization of the problem of construction and use of high-energy microwave weapons, especially electromagnetic bombs. However, in the recent military-professional literature, this issue is little represented. Methods: The available existing literature on the subject was analyzed. Results: It has been established that the general principles of functioning and theoretical bases have been widely available and known for many years. Numerous experiments in specialized institutions have confirmed the electromagnetic pulse effectiveness. This is especially true of sensitivity of devices based on semiconductor technology. Also, it is assumed that, at the current technological level, technical solutions are widely available to a large number of entities. The most common model of electromagnetic bomb dealt with in the literature is the realization of the use of a compression flux generator and an oscillator with a virtual cathode. According to the authors, this variant would ensure that the final product has realistic physical dimensions and sufficient strength to be useful. Another problem identified in the literature is the massive absence of adequate protection measures against the effects of electromagnetic pulses. This applies not only to the civilian but also to the military sector and imposes the need to invest significant resources in order to subsequently increase resilience. Conclusion: The available literature indicates that it is possible to make an electromagnetic bomb of acceptable physical dimensions and power. It is assumed that it would generate an electromagnetic pulse with a power of about 10 GW and a frequency of 5 GHz. In combination with high-precision weapons, even protected devices would be successfully disabled. The wide presence of semiconductor technology in all spheres of life makes this weapon extremely effective and it is realistic to expect its much wider application in the coming period.

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24

Usanov, D. A., M. K. Merdanov, A. V. Skripal, R. V. Zotov, B. N. Korotin, and D. V. Ponomarev. "Influence of External Microwave Fields on the Characteristics of a Square-Pulse RC-Generator." Russian Microelectronics 47, no. 7 (November 2018): 532–37. http://dx.doi.org/10.1134/s1063739718070168.

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25

Bolea, Mario, Jose Mora, Beatriz Ortega, and Jose Capmany. "Optical UWB pulse generator using an N tap microwave photonic filter and phase inversion adaptable to different pulse modulation formats." Optics Express 17, no. 7 (March 16, 2009): 5023. http://dx.doi.org/10.1364/oe.17.005023.

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26

Fouad, Sara, Reda Ghoname, Abd Elmonem Elmahdy, and Abd Elhalim Zekry. "Enhancing Tumor Detection in IR-UWB Breast Cancer System." International Scholarly Research Notices 2017 (March 19, 2017): 1–10. http://dx.doi.org/10.1155/2017/4606580.

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An ultra-wideband (UWB) microwave system for breast cancer detection is presented. The proposed system includes monocycle pulse generator, antipodal Vivaldi antenna, breast model, and calibration algorithm for tumor detection. Firstly, our pulse generator employs transmission gate in glitch generator to achieve several advantages such as low power consumption and low ringing level. Secondly, the antipodal Vivaldi antenna is designed assuming FR4 dielectric substrate material, and developed antenna element (80×80 mm2) features a −10 dB return loss and bandwidth ranges from 2.3 GHz to more than 11 GHz. Thirdly, the phantom breast can be modeled as a layer of skin, fat, and then tumor is inserted in this layer. Finally, subtract and add algorithm (SAD) is used as a calibration algorithm in tumor detection system. The proposed system suggested that horizontal antenna position with 90° between transmitting and receiving antennas is localized as a suitable antenna position with different rotating location and a 0.5 cm near to phantom. The mean advantages of this localization and tracking position around breast is a high received power signal approximately around mv as a higher recognized signal in tumor detection. Using our proposed system we can detect tumor in 5 mm diameter.

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27

Takeuchi, N., D. Ozawa, Y. Yamanashi, and N. Yoshikawa. "On-chip RSFQ microwave pulse generator using a multi-flux-quantum driver for controlling superconducting qubits." Physica C: Superconductivity and its Applications 470, no. 20 (November 2010): 1550–54. http://dx.doi.org/10.1016/j.physc.2010.05.159.

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28

Gao Huailin, 高怀林, 刘濮鲲 Liu Pukun, and 阮存军 Ruan Cunjun. "Simulation analysis of ultra-wideband high power microwave generator based on impedance-matched pulse-forming-line technology." High Power Laser and Particle Beams 24, no. 3 (2012): 723–26. http://dx.doi.org/10.3788/hplpb20122403.0723.

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29

Mu, Hongqian, Muguang Wang, Beilei Wu, Yu Tang, Jing Zhang, and Qi Ding. "Background-free microwave pulse generator based on both bright and dark temporal gate and a single photodetector." Optics Communications 425 (October 2018): 146–51. http://dx.doi.org/10.1016/j.optcom.2018.04.075.

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30

Kurayev, A. A., and V. V. Matveyenka. "Improved and simplified design of the relativistic helitron resonator." Doklady BGUIR 18, no. 5 (September 2, 2020): 5–8. http://dx.doi.org/10.35596/1729-7648-2020-18-5-5-8.

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One of the main trends in microwave electronics is the ultra-large power production. The electron stream energy is converted inside vacuum systems, where the key moment is increasing output power of microwave devices, which is possible only when using more and more powerful electron streams. Increasing electron stream power is possible due to either enhancing the carried currents or as a result of increasing the electron energy. Given the law that connects currents and voltages in electronic systems operating when the current is limited by a spatial charge, the production of ultra-high-power electron flows is associated with the usage of relativistic velocity electrons, i. e. approaching the light speed. Likewise, at present, relativistic electrovacuum devices (traveling-wave lamps and backward-wave lamps) use magnetic focusing for linear relativistic streams, which prevents the implementation of simple superconducting electrodynamic systems, because highfrequency metal superconductivity disappears in constant magnetic fields. Meanwhile, simplified ultra-highpower superconducting device structures can significantly increase the device energy due to the strong ohmic loss reduction, which just limits the device energy, destroying the working electrodynamic system surface by increasing power or pulse duration of the generator. The article outlines the modernized design of a new-type microwave generator – the relativistic helitron. The paper considers a simpler coaxial resonator design, obtained by using the supercritical narrowing of the inner conductor radius by the Hn1l mode of the electromagnetic field, rather than a coaxial resonator with notch filters.

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31

Andreev, S. E., I. L. Bogdankevich, N. G. Gusein-zade, and O. T. Loza. "Effect of the Erosion of Collector Surface on the Operation of a Pulse-Periodic Plasma Relativistic Microwave Generator." Plasma Physics Reports 47, no. 3 (March 2021): 257–68. http://dx.doi.org/10.1134/s1063780x21030028.

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32

Bogdankevich, I. L., O. T. Loza, and D. A. Pavlov. "Shortening of the radiation pulse from a plasma relativistic microwave generator in numerical calculations with plasma simulation by the particle-in-cell method." Bulletin of the Lebedev Physics Institute 37, no. 2 (February 2010): 40–48. http://dx.doi.org/10.3103/s106833561002003x.

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33

Aria, A. K., H. K. Malik, and K. P. Singh. "Excitation of wakefield in a rectangular waveguide: Comparative study with different microwave pulses." Laser and Particle Beams 27, no. 1 (January 8, 2009): 41–47. http://dx.doi.org/10.1017/s0263034609000068.

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AbstractA differential equation governing the wakefield potential (φ) in a plasma filled rectangular waveguide is derived analytically. This equation is solved numerically for the wakefield (Ew) generated with the help of three kinds of microwave pulses, namely sine pulse (SP), rectangular Gaussian pulse (RGP), and rectangular triangular pulse (RTP). The effect of microwave frequency (f), pulse duration (τ), waveguide width (b), equilibrium plasma density (n0), and microwave intensity (I) on the amplitude of the wakefield is studied. This amplitude is increased for the longer pulse duration and higher microwave intensity, but is decreased with growing waveguide width for all types of pulses. With regard to the variation of wakefield amplitude with plasma density, the RTP and SP behave in a similar fashion and the RGP behaves oppositely. The amplitude for the case of RGP gets increased with the plasma density. The amplitude is enhanced at larger microwave frequency for the cases of RGP and SP, but is decreased for the case of RTP. The comparative study of three types of pulses shows that the wakefield with larger amplitude is achieved with the help of rectangular triangular pulse, which is found to be sensitive with waveguide width, pulse duration and microwave intensity.

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34

Kutenkov, O. P., I. V. Pegel, and E. M. Totmeninov. "Explosive Emission Cathode Based on a Carbon Fiber for Long-Term Pulsed-Periodic Mode of Operation and its Application in a High-Power Microwave Pulse Generator Without External Magnetic Field." Russian Physics Journal 57, no. 5 (September 2014): 565–72. http://dx.doi.org/10.1007/s11182-014-0277-8.

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35

Sato, Kazunobu, Rei Hirao, Ivan Timofeev, Olesya Krumkacheva, Elena Zaytseva, Olga Rogozhnikova, Victor M. Tormyshev, et al. "Trityl-Aryl-Nitroxide-Based Genuinely g-Engineered Biradicals, As Studied by Dynamic Nuclear Polarization, Multifrequency ESR/ENDOR, Arbitrary Wave Generator Pulse Microwave Waveform Spectroscopy, and Quantum Chemical Calculations." Journal of Physical Chemistry A 123, no. 34 (August 2, 2019): 7507–17. http://dx.doi.org/10.1021/acs.jpca.9b07169.

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36

Park, Joong Suk, Jeong Woo Han, and Cam Nguyen. "Radio-Frequency Sensors for Nondestructive Evaluation of Materials." Advanced Materials Research 747 (August 2013): 765–68. http://dx.doi.org/10.4028/www.scientific.net/amr.747.765.

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We report several radio-frequency (RF) sensors for possible use in material NDE and process control: an ultra-wide band (UWB) impulse sensor and microwave and millimeter-wave stepped-frequency sensors. The UWB sensor generates ultra-short pulses directly while the stepped-frequency sensors produce ultra-short pulses indirectly through pulse-synthesis. Ultra-short pulses possess ultra-wide bandwidths and have uniquely desirable characteristics such as fine resolution and high accuracy for material assessment. The UWB impulse sensor operates over multiple pulse durations from 450 to 1170 ps with 5.5-GHz RF bandwidth. It performs well through tests of various samples, demonstrating its usefulness for sensing. The microwave stepped-frequency sensor operates from 0.6 to 5.6 GHz and the millimeter-wave stepped-frequency sensor operates from 29.72-37.7 GHz. They have demonstrated abilities in surface and near-surface sensing of various structures. These developed compact RF sensors are attractive for NDE and process control of materials and various other sensing applications.

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37

Fang, Jinyong, Jiangniu Wu, Huijun Huang, Haoliang Zhang, Jing Sun, Jianjun Wang, and Li Li. "Path Encoding Pulse Compression for Obtaining Novel HPM with Ultrahigh Repetition Frequency." Laser and Particle Beams 2021 (September 7, 2021): 1–12. http://dx.doi.org/10.1155/2021/3259950.

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Based on the path encoding pulse compression teleology, a novel method for obtaining high-power microwave (HPM) pulse with ultrahigh repetition frequency is proposed in this paper. The mechanism of the path encoding pulse compression teleology is first introduced. And then, the obtained HPM pulse is analyzed. Theoretical analysis shows that the peak power of MW level and the repetition frequency of MHz level for the generated HPM pulse can be easily reached. To demonstrate the effectiveness of this method for obtaining HPM pulse with ultrahigh repetition frequency characteristic, a HPM-obtaining experiment was carried out based on an S-band microwave source. The HPM pulses with the width of 1 ns, 2 ns, and 3 ns are studied, respectively. The measured results show that the HPM pulse with the power higher than 100 kW and the repetition frequency of 250 kHz at the frequency of 2.856 GHz is easily obtained. The repetition frequency of the generated HPM pulse can be easily changed. Because the pulse with the power higher than 100 kW and the repetition frequency of several hundreds of kHz is obtained for the first time, this type of pulse will have a broad prospect of application in the communication, radar, and electronic countermeasure fields. In addition, the effect experiment of interfering communication and control links was carried out by utilizing the ultrahigh repetition frequency characteristic of the generated HPM pulse. Also, the experiment results show the feasibility of this pulse for interfering the communication and control links.

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38

Kim, J., S. P. Kuo, and Paul Kossey. "Modelling and numerical simulation of microwave pulse propagation in an air-breakdown environment." Journal of Plasma Physics 53, no. 3 (June 1995): 253–66. http://dx.doi.org/10.1017/s0022377800018183.

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The dependences of the propagation characteristics of an intense microwave pulse on the intensity, frequency, width and shape of the pulse in an air- breakdown environment are examined. Numerical simulations lead to a useful empirical relation P3W = α = const, where P and W are the incident power and width of the pulse and α depends on the percentage of the pulse energy transferred from the source point to a given position. The results also show that, using a single unfocused microwave pulse transmitted upwards from the ground, the maximum electron density produced at, for example, 50 km altitude is limited by the tail erosion effect to below 106 cm-3. Repetitive-pulse and focused-beam approaches are then examined. Both approaches can increase the maximum electron density by no more than an order of magnitude. Hence a scheme using two obliquely propagating pulses intersecting at the desired height (e.g. 50 km) is considered. It is shown that the generated electron density at the lowest intersecting position can be enhanced by more than two orders of magnitude.

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39

Mohamed, M. M., T. Uchida, and S. Minami. "Direct Sample Introduction of Solid Material into a Pulse-Operated MIP." Applied Spectroscopy 43, no. 5 (July 1989): 794–800. http://dx.doi.org/10.1366/0003702894202139.

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To minimize problems caused by sample introduction into a microwave-induced plasma (MIP), we have developed a system consisting of a spark ablation cell and a pulse-operated microwave-induced plasma (pulsed-MIP). An aerosol is generated from solid samples with the use of a spark discharge. The resultant material is swept into a pulsed-MIP. Design and fabrication criteria for the spark source and the spark ablation cell are presented. The combined sources show enhanced precision, stability, signal-to-noise levels, and detection limits relative to direct spark emission. Analytical calibration curves and detection limit data are shown for nickel, manganese, and chromium in steel samples. Time-resolved data are also shown.

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40

LIU, GUOZHI, WENHUA HUANG, HAO SHAO, SHI QIU, HONGJUN WANG, JINGYUE LIU, FENG WANG, ZHANFENG YANG, and YONGZHI QIAO. "Effects of diode current on high power microwave generation in a vircator." Journal of Plasma Physics 75, no. 6 (April 15, 2009): 787–98. http://dx.doi.org/10.1017/s0022377809007909.

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AbstractAn experiment of a virtual cathode oscillator (vircator) built on the low impedance intense electron beam accelerator Flash II is reported. A novel spectrum diagnosis method—a circulating dispersion line—is proposed. A thin oil layer coated graphite cathode is introduced in the experiment to decrease the delay time of the explosive emission process and obtain a homogeneous electron beam emission for improving the high-power microwave (HPM) generation efficiency. The effect of diode current on HPM generation in the vircator system is discussed. The HPM pulse width has a strong connection with the diode current waveform. For most shots, corresponding to the time that microwave emission starts, there is an inflection point in the diode current pulse. Compared with the case that no microwave is generated, the diode current increases more slowly following the inflection point. HPM generation terminates when the beam current reaches the self-pinching critical current of the diode.

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41

Gong, Peng Wei, Zhe Ma, Hong Mei Ma, and Chun Tao Yang. "Experimental Investigation of Terahertz Temporal Response of a Photoconductive Switch." Advanced Materials Research 571 (September 2012): 491–95. http://dx.doi.org/10.4028/www.scientific.net/amr.571.491.

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Picosecond or subpicosecond electrical pulses can be generated from femtosecond laser excited photoconductive switches, and this technique is an effective method to characterize the rise time of the broadband oscilloscopes recently. In this paper, low temperature grown GaAs (LT-GaAs) is used as the substrate of the photoconductive switch which is excited by the femtosecond laser. After propagating along a coplanar waveguide, the generated terahertz pulses are transferred to a 1.85 mm coaxial cable through a microwave probe. The pulse width is measured in a 70 GHz sampling oscilloscope, the FWHM value is about 7.4 ps.

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42

Karelin, S. Y., V. G. Korenev, V. B. Krasovitsky, A. N. Lebedenko, I. I. Magda, V. S. Mukhin, V. G. Sinitsin, and N. V. Volovenko. "PULSED POWER TO MICROWAVES CONVERSION IN NONLINEAR TRANSMISSION LINES." Radio physics and radio astronomy 26, no. 3 (September 14, 2021): 250–55. http://dx.doi.org/10.15407/rpra26.03.250.

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Purpose: Experimental results and numerical simulations are presented, concerning effects of microwave generation in coaxial transmission lines which are fed with unipolar, high voltage electric pulses. The work is aimed at clarifying the relative importance of several mechanisms that could be responsible for the appearance of microwave-frequency oscillations in the course of pulse propagation through the guiding structure. Design/methodology/approach: Dispersive and filtering properties of coaxial waveguides that involve three structural sections are discussed. These latter follow one another along the axis of symmetry. Two identical sections at the input and output are filled with an isotropic liquid dielectric, while the middle part may, in addition, be either partially or fully filled with a non-conductive gyrotropic material. The inserted core represents a set of ferrite rings showing a nonlinear response to the initial high voltage, pulsed excitation. Throughout the series of measurements, the diameters of the inner conductor and of the ferrite core were kept constant. The outer conductor’s diameter was varied to permit analysis of the effect of that size proper and of the degree to which the cross-section is fi lled with ferrite. The gyrotropic properties of the ferrimagnetic material were realized through application of a magnetic bias field from an external coil. The measurements were made for a variety of pulsed voltage magnitudes from the range of hundreds of kilovolts, and magnetic bias fields of tens kiloamperes per meter. Findings: As observed in our experiments, as well as in papers by other writers, a unipolar pulse coming from the radially uniform front-end section, further on gives rise to quasi-monochromatic voltage oscillations. These appear as soon as the pulse has advanced a sufficient distance into the radially nonuniform portion of the guide. The oscillations may consist of a small number of quasi-periods, which suggests a large spectral line width. However, by properly selecting geometric parameters of the wave guiding line and the characteristics of the initial pulsed waveform it proves possible to obtain output frequencies of about units of gigahertz and pulse powers at subgigawatt levels. Conclusions: The frequencies and amplitudes of the appearing oscillations, as well as their spectral widths, are governed by the complex of dispersive and non-linear properties of the guiding structure. The diameters of the inner and outer coaxial conductors in the line, diameter of the ferrimagnetic insert and its intrinsic linear dispersion determine the set of waveguide modes capable of propagating through the line. An oscillating part of the waveform may appear and get separated from the main body of the pulse if it has originated at a higher frequency than the cut-off value for a different mode than the initial TEM. Key words: unipolar pulse, coaxial transmission line, microwave frequency oscillations, dispersion laws, waveguide modes

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43

Xiao, R. Z., X. W. Zhang, L. J. Zhang, X. Z. Li, L. G. Zhang, W. Song, Y. M. Hu, et al. "Efficient generation of multi-gigawatt power by a klystron-like relativistic backward wave oscillator." Laser and Particle Beams 28, no. 3 (September 2010): 505–11. http://dx.doi.org/10.1017/s0263034610000509.

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AbstractEfficient generation regime with a high power output has been experimentally realized in a klystron-like relativistic backward wave oscillator, in which a modulation cavity is inserted between the slow wave structure to decrease the energy spread of modulated beam electrons, and an extraction cavity is employed at the end of the slow wave structure to further recover energy from the electron beam. At a guiding magnetic field of 2.2 T, a microwave pulse with power of 6.5 GW, frequency of 4.26 GHz, pulse duration of 38 ns, and efficiency of 36% was generated when the diode voltage was 1.1 MV, and diode current was 16.4 kA. When the diode voltage was 820 kV, efficiency up to 47% with microwave power 4.4 GW was also realized experimentally.

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44

Li, Limin, L. Chang, L. Zhang, J. Liu, G. Chen, and J. Wen. "Development mechanism of cathode surface plasmas of high current pulsed electron beam sources for microwave irradiation generation." Laser and Particle Beams 30, no. 4 (August 1, 2012): 541–51. http://dx.doi.org/10.1017/s0263034612000468.

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AbstractThis paper presents the development mechanism of surface plasmas of carbon-fiber-cathode electron beam source and its effects on the operation of a high-power microwave source, reflex triode vircator powered by about 400 kV, 9 kA, about 350 ns pulsed power accelerator. Based on the current and voltage characteristics of diodes using carbon fiber cathode, the axial expansion velocity is 1.2 cm/μs and the delay time of explosive emission is 2 ns. Further, the comparison of carbon fiber and stainless steel cathodes is made. It was found that the threshold electric field for carbon fiber cathode is about 25 kV/cm, and the delay time of explosive emission and threshold electric field for stainless steel cathode is, respectively, 4.5 ns and 40 kV/cm. The radial expansion velocity of individual emitting centers is estimated to be 1.2 cm/μs, equal to the axial expansion velocity, and this shows the cathode plasma spots spherically expand. In the optimal diode gap for microwave irradiation or at the average current density of 230 A/cm2using carbon fiber cathode, the screening radius was 0.67 cm, the lifetime of cathode emitting centers was about 60 ns, the cathode plasma density was 5 × 1015 cm−3, and the Debye radius of cathode plasma was <3 × 10−5 cm−3. The self-quenching behavior of explosive emission centers occurs, due to the process of cathode surface material release and cooling. The generation and self-quenching of emitting centers, and screening effect of cathode plasmas determine the increase and decrease of cathode emitting area, which is independent of the current density and background pressure. The relation between the lifetime of virtual cathode and background pressure was discussed. It was found, both theoretically and experimentally, that a lower background pressure indicates a longer microwave pulse or a better microwave waveform. It was observed by comparison that the temporary behavior of cathode emitting area is similar to the development process of microwave pulse. The changes of emitting area affects the stability of beam current injected into the virtual cathode region, further leading to the fluctuation of microwave pulse of vircator.

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45

Artemenko, Sergey N., Valery L. Kaminsky, Gennady M. Samoylenko, and Boris A. Alekseev. "Superconducting Cavities in Systems of the Resonant Microwave Pulse Compression." Advanced Materials Research 1084 (January 2015): 266–72. http://dx.doi.org/10.4028/www.scientific.net/amr.1084.266.

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Evaluations for possible using of superconducting materials in high power microwave generators based on the method of the resonant microwave compression were made. As an example the relationship between the power amplification factor and frequency was determined for superconducting rectangular cavities. Capabilities of superconducting cavities as energy accumulators were analyzed. Microwave power value required for feeding superconducting accumulator is estimated. Experimental results of storing and extracting the energy in superconducting cavities are presented.

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46

Biggs, David R., and Mark A. Cappelli. "Tunable microwave pulse generation using discharge plasmas." Applied Physics Letters 109, no. 12 (September 19, 2016): 124103. http://dx.doi.org/10.1063/1.4963268.

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47

Baránková, Hana, Ladislav Bardos, and Adela Bardos. "Non-Conventional Atmospheric Pressure Plasma Sources for Production of Hydrogen." MRS Advances 3, no. 18 (2018): 921–29. http://dx.doi.org/10.1557/adv.2018.103.

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ABSTRACTThe atmospheric pressure plasma sources with a coaxial geometry were used for generation of the radio frequency, microwave and pulsed dc plasmas inside water and aqueous solutions. Pulsed dc plasma generated in ethanol-water mixtures leads to production of the hydrogen-rich synthesis gas with hydrogen content up to 65 %. The effect of various plasma generation regimes on the performance of plasma, on the hydrogen production efficiency and on the hydrogen-rich synthesis gas production was examined. A role of the composition of the ethanol-water mixture was investigated.

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48

Fazio, M. V., and R. F. Hoeberling. "A reflexing electron microwave amplifier for rf particle accelerator applications." Laser and Particle Beams 6, no. 3 (August 1988): 613–20. http://dx.doi.org/10.1017/s0263034600005553.

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The evolution of rf-accelerator technology toward high-power, high-current, lowemittance beams produces an ever-increasing demand for efficient, very high power microwave power sources. The present klystron technology has performed very well but is not expected to produce reliable gigawatt peak-power units in the 1- to 10-GHz regime. Further major advancements must involve other types of sources. The reflexing-electron class of sources can produce microwave powers at the gigawatt level and has demonstrated operation from 800-MHz to 40-GHz. The pulse length appears to be limited by diode closure, and reflexing-electron devices have been operated in a repetitively pulsed mode. A design is presented for a reflexing electron microwave amplifier that is frequency and phase locked. In this design, the generated microwave power can be efficiently coupled to one or several accelerator loads. Frequency and phase-locking capability may permit parallel-source operation for higher power. The low-frequency (500-MHz to 10-GHz) operation at very high power required by present and proposed microwave particle accelerators makes an amplifier, based on reflexing electron phenomena, a candidate for the development of new accelerator power sources.

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49

Ling, Jun-Pu, Jun-Tao He, Jian-De Zhang, Tao Jiang, and Li-Li Song. "A Ku-band coaxial relativistic transit-time oscillator with low guiding magnetic field." Laser and Particle Beams 32, no. 2 (March 28, 2014): 295–303. http://dx.doi.org/10.1017/s0263034614000135.

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AbstractA novel coaxial relativistic transit-time oscillator with low guiding magnetic field is proposed and investigated to generate high power microwave at Ku-band. With the coaxial structure and a quasi body wave adopted as the operating mode, the device has a larger space-charge limiting current, higher power handling capacity, and lower guiding magnetic field. Moreover, for further improving the output power, a coaxial TM02mode resonant reflector is well designed. Main structure parameters of the device are optimized by particle in cell simulations. A typical simulation result is that, with a 358 keV, 7.25 kA beam guided by a magnetic field of about 0.7 T, an 810 MW microwave pulse at 14.25 GHz is generated, yielding a conversion efficiency of about 31%. The primary experiments are also carried out. At a low guiding magnetic field of 0.7 T, a microwave pulse with power of 400 MW, pulse duration of 30 ns, frequency of 14.3 GHz close to the simulation one, and efficiency of 15.4% is generated.

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50

Pötz, Walter, and Xuedong Hu. "Coherent Control of Light Absorption and Carrier Dynamics in Semiconductor Nanostructures." VLSI Design 8, no. 1-4 (January 1, 1998): 203–7. http://dx.doi.org/10.1155/1998/32057.

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We present two examples of coherent control of inter(sub)band transitions in a semiconductor double well by coherent light sources. Accounting for the upper hole subband and two lowest electron subbands, a microscopic theoretical analysis shows that electron-hole pair generation by a sub-picosecond pump pulse can be controlled by the intensity and the phase of a dc microwave field which resonantly couples the two electron subbands. Light absorption can be either enhanced or reduced. Secondly, it is shown that proper combination of two pulsed laser fields allows control of electron inter(sub)band transitions and final-state population, i.e., the formation of indirect versus direct excitons.

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