Showing papers by "Yanyu Wei published in 2013"
TL;DR: In this paper, a millimeter-wave sheet beam backward wave oscillator is presented for high-power high-frequency microwave radiation, where the rectangular waveguide grating structure is used as its slow wave structure.
Abstract: The sheet beam vacuum electron device is an attractive choice for generating high-power high-frequency microwave radiation. A millimeter-wave sheet beam backward wave oscillator (BWO) is presented in this paper. The rectangular waveguide grating structure is used as its slow wave structure. The BWO is driven by a sheet beam with a cross-sectional area of 30 mm × 1 mm which is generated by a thin cathode. For a beam voltage of 167 kV and a beam current of 1.4 kA, the output power is 40 MW at 36.6 GHz. The beam-wave interaction efficiency is about 17%, which is higher than that of conventional hollow beam BWO. It is clear from the results presented in this paper that the sheet beam device is promising for producing high-efficiency high-power millimeter-wave radiation.
47 citations
TL;DR: In this article, the angular log-periodic meander-line SWS was proposed for a radial traveling wave tube (TWT) and the beam-wave interaction was calculated using the particle-in-cell method.
Abstract: A novel slow wave structure (SWS) named angular log-periodic meander-line is proposed for a radial traveling wave tube (TWT). In this paper, a 30 log-periods microstrip angular log-periodic meander-line SWS is studied. The dispersion of this kind of SWS is weak, which shows that it can work in a wide operating bandwidth. The more important advantage is that the operating voltage is much lower than that of the conventional TWT at the same operating frequency and the geometrical dimension is also much smaller than that of the conventional TWT. The beam–wave interaction of the angular log-periodic meander-line TWT is calculated using the particle-in-cell method. When the operating voltage is 1624 V, this kind of TWT can give 156.5-W output power at 35 GHz, the gain is 21.9 dB, and the electron efficiency is ${\sim}17.7\%$ . With this kind of TWT as mentioned, the concept of radial integrated angular log-periodic meander-line TWT is proposed, which can provide a new way to obtain higher output power.
38 citations
TL;DR: In this paper, a ridge-vane-loaded folded waveguide combined with pencil electron beam has been proposed for millimeter-wave traveling-wave tubes, and the high-frequency characteristics including the dispersion properties and the interaction impedance of this kind of structure have been analyzed by means of an equivalent circuit based on the transmission-line cascading network.
Abstract: A novel slow-wave structure called ridge-vane-loaded folded waveguide combined with pencil electron beam has been proposed for millimeter-wave traveling-wave tubes. The high-frequency characteristics including the dispersion properties and the interaction impedance of this kind of structure have been analyzed by means of an equivalent circuit based on the transmission-line cascading network. The theoretical results agree well with those obtained by the 3-D electromagnetic high-frequency simulation software. The nonlinear interaction between the electron beam and the electromagnetic field is investigated with the help of the Computer Simulation Technology Particle Studio 3-D particle-in-cell (PIC) code. The PIC simulation results revealed that this kind of structure could produce about 56 W of peak output power at 0.22-THz when the cathode voltage and current of the pencil electron beam are set to 14.65 kV and 50 mA, respectively. Moreover, the maximum gain and interaction efficiency can reach 37.5 dB and 7.7% at 0.22 THz, respectively. A simulated 3-dB bandwidth of ~ 30 GHz is demonstrated.
33 citations
TL;DR: In this paper, a high-order harmonic generation process was introduced to a traveling-wave tube (TWT)-like device-the high-harmonic TWT or HHTWT was configured as a frequency multiplier and amplifier with W-band (millimeter wave) input signals and THz output power.
Abstract: We propose a new type of terahertz (THz) radiation source based on the electron beam-wave interaction. A high-order harmonic-generation process was introduced to a traveling-wave tube (TWT)-like device-the high-harmonic TWT or HHTWT. The scheme is configured as a frequency multiplier and amplifier with W-band (millimeter wave) input signals and THz output power. Simulations show that operation at the seventh harmonic is possible and other order harmonic waves were suppressed. The output frequency can be tuned continuously over a 30-GHz bandwidth with more than 20-dBm output power. The peak output power is about 30 dBm at 707 GHz. The output frequency is insensitive to beam voltage jitter.
20 citations
TL;DR: In this article, a novel winding microstrip meander-line slow-wave structure (SWS) has been proposed to develop lowvoltage and high power millimeter-wave traveling-wave tube.
Abstract: A novel winding microstrip meander-line slow-wave structure (SWS) has been proposed to develop low-voltage and high-power millimeter-wave traveling-wave tube. This structure, which interacts with a round electron beam, evolves from a V-shaped microstrip meander-line SWS. The electromagnetic characteristics and beam-wave interaction of this novel structure are calculated in this letter. As is seen from the results, traveling-wave tubes with this novel circuit can provide over 130-W output power ranging from 58 to 63 GHz. In addition, the maximum electronic efficiency may reach 10% at 61 GHz.
18 citations
TL;DR: In this article, a new type of folded frame slow-wave structure (SWS) is introduced and used in the design of a lowvoltage, high efficiency, and widebandwidth millimeter-wave traveling-wave tube (TWT).
Abstract: A new type of folded frame slow-wave structure (SWS) is introduced and used in the design of a low-voltage, high-efficiency, and widebandwidth millimeter-wave traveling-wave tube (TWT). The high-frequency characteristics of the folded frame structure, including dispersion properties, coupling impedances, and reflection characteristics are investigated. The beam-wave interaction of the TWT with the folded frame SWS working at the millimeter-wave frequency range is also calculated using 3-D particle-in-cell algorithms. The simulation results reveal that with sheet electron beam parameters of 6000 V and 0.2 A, the average output power and electron efficiency can reach 196 W and 16.3%, respectively. Compared with the symmetric double V-shaped microstrip meander-line SWS, the folded frame SWS has larger coupling impedances and can generate higher output power.
13 citations
TL;DR: In this paper, a slotted helix slow-wave structure (SWS) is proposed to develop high power, widebandwidth, high reliability millimeter-wave traveling-wave tube (TWT).
Abstract: A novel slotted helix slow-wave structure (SWS) is proposed to develop high power, wide-bandwidth, high reliability millimeter-wave traveling-wave tube (TWT). This structure, which can improve the heat dissipation capability of the helix SWS, evolves from conventional helix SWS with three parallel rows of rectangular slots made in the outside of the helix. In this paper, thermal stress analysis, the electromagnetic characteristics and the beam-wave interaction of this structure are investigated. The conclusions of this paper will be a great help for the design of millimeter-wave traveling-wave tube.
10 citations
TL;DR: In this paper, a double-ridge loaded folded waveguide (FWG) traveling-wave tube (TWT) amplifler for sheet electron beam working at 140GHz is proposed, and the dispersion relation and interaction impedance characteristics have been analyzed based on the equivalent circuit method.
Abstract: A novel double-ridge loaded folded waveguide (FWG) traveling-wave tube (TWT) amplifler for sheet electron beam working at 140GHz is proposed in this paper. The dispersion relation and interaction impedance characteristics have been analyzed based on the equivalent circuit method. The transmission properties and nonlinear interaction are investigated. The simulation results reveal that the double-ridge loaded FWG-TWT with sheet electron beam can make full use of relatively large electronic flelds, and the average output power can be over 110W at 140GHz when the electron beam voltage and the current of the sheet beam are set to 12.7kV and 150mA, respectively. Meanwhile, the maximum gain and interaction e-ciency can reach 34dB and 12%, respectively. Compared with the traditional FWG-TWT, the novel FWG-TWT has the advantages of much higher e-ciency and bigger output power.
5 citations
TL;DR: In this article, the beam echo harmonic effect is applied to a traveling wave tube like device, which is configured as a combination of a frequency multiplier and amplifier with, for instance, W-band (millimeter wave) input signals and terahertz output power.
Abstract: A new type of terahertz radiation source based on the nonrelativistic electron beam-wave interaction is proposed. Here, the beam echo harmonic effect is applied to a traveling wave tube like device. The scheme is configured as a combination of a frequency multiplier and amplifier with, for instance, W-band (millimeter wave) input signals and terahertz output power. A one-dimensional model of this device shows that a 10th order harmonic-wave can be generated while other harmonic waves are suppressed. The device only requires a readily available input source (W-band), and the output frequency can be tuned continuously over a wide band.
5 citations
21 May 2013
TL;DR: In this paper, the simulation results on sheet beam electron gun and sheet beam transport in a uniform magnetic field were presented, and it was shown that the sheet beam with size 4.6 mm×0.4 mm, generated by the electron gun with 20 kV, 560 mA, can stably pass through the beam tunnel with transverse size 6 mm×1 mm and the length 120 mm in uniform magnetic fields.
Abstract: In this paper, we have presented the simulation results on sheet beam electron gun and sheet beam transport in a uniform magnetic field. It is shown that the sheet beam with size 4.6 mm×0.4 mm, generated by the electron gun with 20 kV, 560 mA, can stably pass through the beam tunnel with transverse size 6 mm×1 mm and the length 120 mm in a uniform magnetic field.
4 citations
21 May 2013
TL;DR: In this paper, the angular log-periodic microstrip meander line was proposed as a slow wave structure, which is mainly determined by three parameters only, and the calculation results show that it has a very weakly dispersion s.
Abstract: A novel slow-wave-structure (SWS) named angular log-periodic micro-strip meander-line was proposed in this paper. This kind of slow wave structure is mainly determined by 3 parameters only, and the calculation results show that it has a very weakly dispersion s. That is to say, its operation bandwidth would be very wide. Its another advantage is the low operation voltage. The radial normalized phase velocity by light velocity of wave can be as low as 0.04, while the DC voltage just 400 V, which is much smaller than conventional traveling wave tubes. The dispersion and transmission characteristics of this kind of slow wave structure were obtained.
TL;DR: In this article, a double-slotted helix slow-wave structure is proposed and employed in the interaction circuit, and negative phase-velocity tapering technology is used to improve electronic e-ciency.
Abstract: The design and analysis of a high power and high e-ciency helix traveling-wave tube operating in the Ka-band are presented. First, a double-slotted helix slow-wave structure is proposed and employed in the interaction circuit. Then, negative phase-velocity tapering technology is used to improve electronic e-ciency. From our calculations, when the design voltage and beam current are set to be 18.45kV and 0.2A, respectively, this tube can produce average output power over 800W ranging from 28GHz to 31GHz. The corresponding conversion e-ciency varies from 21.83% to 24.16%, and the maximum output power is 892W at 29GHz.
21 May 2013
TL;DR: In this paper, a Ka-band high power sheet beam beam backward wave oscillator with a double-grating rectangular waveguide is presented, where the double grating waveguide was used as the slow wave structure.
Abstract: A Ka-band high power sheet beam backward wave oscillator (BWO) has been presented in this paper. In which the double-grating rectangular waveguide is used as the slow wave structure. A high power sheet beam with cross section 30mm×1mm is produced by a thin cathode. The output power exceeds 35 MW at 31.1 GHz. The beam-wave interaction efficiency is about 14.7%.
TL;DR: In this paper, a slotted helix slow-wave structure (SWS) is proposed to develop a high power, widebandwidth, and high reliability millimeter-wave traveling-wave tube (TWT).
Abstract: A novel slotted helix slow-wave structure (SWS) is proposed to develop a high power, wide-bandwidth, and high reliability millimeter-wave traveling-wave tube (TWT). This novel structure, which has higher heat capacity than a conventional helix SWS, evolves from conventional helix SWS with three parallel rows of rectangular slots made in the outside of the helix tape. In this paper, the electromagnetic characteristics and the beam-wave interaction of this novel structure operating in the Ka-band are investigated. From our calculations, when the designed beam voltage and beam current are set to be 18.45 kV and 0.2 A, respectively, this novel circuit can produce over 700-W average output power in a frequency range from 27.5 GHz to 32.5 GHz, and the corresponding conversion efficiency values vary from 19% to 21.3%, and the maximum output power is 787 W at 30 GHz.
01 Sep 2013
TL;DR: In this article, the design of the staggered double vane slow wave structure (SWS) for two bands of traveling wave tube (TWT) amplifier, one for Ka-band and another one for W-band, has been presented.
Abstract: Design of the staggered double vane slow wave structure (SWS) for two bands of traveling wave tube (TWT) amplifier, one for Ka-band and another one for W-band, has been presented in this paper. The high-frequency characteristics of this kind of structure were calculated by the HFSS eigenmode solver. And particle-in-cell method was carried out to investigate the amplification performance of this structure. Moreover, the experimental models, systems, and the results of this SWS for W-band TWT are exhibited in the end.
TL;DR: In this article, a study on the low voltage, high efficiency and wide bandwidth travelling wave tube by using a novel folded frame slow-wave structure is carried out, and the radio frequency characteristics of the folded frame structure, including dispersion property, interaction impedances, and reflection property are investigated.
Abstract: A study on the low voltage, high efficiency and wide bandwidth travelling wave tube by using a novel folded frame slow-wave structure is carried out in this paper. The radio frequency characteristics of the folded frame structure, including dispersion property, interaction impedances, and reflection property are investigated and compared to the similar symmetric double V-shape meander-line structure. Then, the beam-wave interaction process of the folded frame travelling wave tube (TWT) with rectangular sheet electron beam is simulated by 3-D particle-in-cell algorithms. The results show that the output power and electron efficiency can reach 259 W and 13.5% at the center frequency of 140 GHz, respectively. Simultaneously, the instantaneous 3-dB bandwidth is 24 GHz. Compared to the symmetric double V-shaped TWT, the output power and electron efficiency of the folded frame TWT are increased.
21 Oct 2013
TL;DR: In this article, a taper H-plane loaded folded waveguide (FWG) slow wave structure (SWS) for traveling wave tube (TWT) amplifier has been presented.
Abstract: A novel taper H-plane loaded folded waveguide (FWG) slow wave structure (SWS) for traveling wave tube (TWT) amplifier has been presented. The high-frequency characteristics and the amplification performance have been investigated. The results implied that this structure possessed higher transverse dimension and higher efficiency than those of the traditional FWG-SWS.
01 Oct 2013
TL;DR: In this article, a novel microstrip meander-line slow-wave structure (SWS) is proposed for using in V-band traveling-wave tube (TWT), which has higher interaction impedance by contrasting analysis of the conventional U-shaped SWS.
Abstract: In this paper, a novel microstrip meander-line slow-wave structure (SWS) is proposed for using in V-band traveling-wave tube (TWT). The new omega-shaped microstrip meander-line slow-wave structure has higher interaction impedance by contrasting analysis of the conven-tional U-shaped microstrip meander-line SWS. The transmission characteristics, dispersion characteristic, coupl-ing impedance and beam-wave interaction are simulated by utilizing the simulation software HFSS and CST. The calculation of beam-wave interaction indicated that, at a beam current of 0.1 A and a beam voltage of 7.1 kV, the new microstrip meander-line SWS is capable of delivering more than 28.5 W output power. And its interaction efficiency reaches 12.3% with a transient 3dB bandwidth of 5 GHz (ranging 57.5 GHz to 62.5 GHz).
21 May 2013
TL;DR: In this paper, a modified slotted helix slow-wave structure is proposed to develop high-power, widebandwidth millimeter TWT, which would lead to higher output power in millimeterwave TWT.
Abstract: A modified slotted helix slow-wave structure is proposed to develop high-power, wide-bandwidth millimeter TWT. The electromagnetic characteristics are calculated by HFSS. The results show that the modified structure has higher interaction impedance and lower attenuation compared with original slotted helix SWS, which would lead to higher output power in millimeterwave TWT.
TL;DR: In this paper, a double-groove loaded folded waveguide structure (FWSWS) was designed and numerically modelled for millimeter-wave traveling-wave tubes.
Abstract: A W-band traveling-wave tube (TWT) with double-groove loaded folded waveguide structure (FWSWS) has been designed and numerically modelled. The nonlinear performance of such a TWT is investigated by a particle-in-cell code MAGIC3D. Simulation results indicate this TWT produces a saturated electromagnetic power of 170.2 W at 90 GHz, corresponding to 36.9 dB gain and 69.6 mm interaction distance. A comparison between the novel folded waveguide traveling-wave tube (FWTWT) and the conventional one is also carried out to verify the effect of groove loading on the large-signal performance of TWT. Within the same working conditions, the double groove-loaded FWTWT could obtain higher saturated output power and gain in a shorter interaction length. The maximum of output power and gain of this novel TWT is 58.6% and 10% higher than those of the conventional FWTWT, while the 3-dB bandwidth of TWT is reduced to 4 GHz. With the additional advantage of ease of fabrication based on micro-electro-mechanical systems (MEMS) technologies, the double-groove loaded FWSWS is suitable for a millimeter-wave TWT with high power capacity and gain.