Enhancement of Coherent THz Smith-Purcell Radiation by Resonance Overlapping

Li, Weiwei; Xu, Yuanfang; Lu, Yalin; He, Zhigang; Jia, Qika; Wang, Lin

doi:10.1007/s10762-016-0304-7

Cited by 4 publications

(4 citation statements)

References 31 publications

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“…Up to now, the method has been applied in the small-signal model building for kinds of transistors such as complementary metal-oxidesemiconductor field-effect transistors, [11,12] GaAs p-type high electron mobility transistors (HEMTs), [13] GaN HEMTs, [14] and InP HBTs. [15][16][17][18] Furthermore, the EM simulation approach can also be used in the noise model building for microwave transistors. In Ref.…”

Section: Introductionmentioning

confidence: 99%

An electromagnetic simulation assisted small signal modeling method for InP double-heterojunction bipolar transistors

Wang¹,

Ding²,

Su³

et al. 2022

Chinese Phys. B

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A convenient and practical EM assisted small-signal model extraction method for InP DHBTs is presented in this paper. Parasitic parameters of pad and electrode fingers are extracted by means of 3-D electromagnetic (EM) simulation. The simulations with a new excitation scheme are closer to the actual on-wafer measurement conditions. Appropriate simulation settings are calibrated by comparing measurement and simulation of OPEN and SHORT structures. A simpler π-type topology is proposed for the intrinsic model, in which the base-collector resistance Rµ, and output resistance Rce are deleted, and a capacitance Cce is introduced to characterize the capacitive parasitic caused by the collector finger and emitter ground bar. The intrinsic parameters are all extracted by exact equations that are derived from rigorous mathematics. The method is characterized by its ease of implementation and the explicit physical meaning of extraction procedure. Experimental validations are performed at four biases for three InGaAs/InP HBT devices with 0.8×7 µm2, 0.8×10 µm2 and 0.8×15 µm2 emitter, and quite good fitting results are obtained at the range of 0.1 to 50 GHz.

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Section: Introductionmentioning

confidence: 99%

An electromagnetic simulation assisted small signal modeling method for InP double-heterojunction bipolar transistors

Wang¹,

Ding²,

Su³

et al. 2022

Chinese Phys. B

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“…THz near-field imaging methodologies mainly include two categories of probes, aperture type and aperture-less type. In both cases, the ultra-high resolution that breaks through the diffraction limit is predicated on the generation and exploitation of evanescent waves in the vicinity of the probe apex [14]. This kind of imaging modality has a wide range of applications, including non-destructive access to surface and subsurface structural information of the sample [15], micro/nanostructure imaging [16,17], biomedical imaging [18,19], and crystal characterization [20].…”

Section: Introductionmentioning

confidence: 99%

Novel configuration of aperture-type terahertz near-field imaging probe

Wang

Zhang

Liang

et al. 2020

J. Phys. D: Appl. Phys.

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A near-field imaging probe based on a size-optimized tapered frustum with concave aperture is designed and demonstrated. The performance of the new probe is evaluated by finite difference time-domain electromagnetic simulation and near-field imaging experiments. The new probe structure eliminates the large amount of reflection of the terahertz (THz) wave at the probe aperture due to impedance mismatch, and increases the electric field intensity that can be transmitted through the aperture by a factor of three within the near-field domain outside the aperture. These beneficial changes lead to an increase in the spatial resolution of the new probe, while concurrently prolonging the decay length of the electric field intensity transmitted from the apex, so that the THz imaging beam can transmit a longer distance and the stringent near-field conditions are moderated. An imaging resolution of at least 10 µm (λ/270) at 0.11 THz is obtained experimentally, with excellent repeatability, while the workable near-field distance is also increased substantially, making the new probe feasible for imaging subsurface microstructures.

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“…The choice of SP radiation is attributed to the facts that the SP radiation mechanism allows a number of possibilities in controlling the properties of the generated radiation. 2,[12][13][14][15][16] This mechanism can also be explored to develop a promising femtosecond electron beam diagnostic tool to monitor the longitudinal (time) profile or periodicity of the pre-bunched beam. 2,[17][18][19][20] In 2005, the concept of frequencylocked cSPr induced by electron bunch trains was put forward, with the bunch spacing equal to 1.75 cm (Ref.…”

mentioning

confidence: 99%

“…( 1) that all high harmonics of this fundamental frequency (m > 1) will be also measured (if present) at the same position of the detector. 13 The cSPr experiment setup is shown in Fig. 2.…”

mentioning

confidence: 99%

Selective excitation and control of coherent terahertz Smith-Purcell radiation by high-intensity period-tunable train of electron micro-bunches

Liang

Wang

et al. 2018

Applied Physics Letters

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We report the observation and studies of selective excitation and control of terahertz (THz) coherent Smith-Purcell radiation (cSPr) from a train of sub-picosecond-period electron microbunches. The coherence of the radiation from such a train has been demonstrated. The spectrum of cSPr was measured and the selective excitation of the first and the second harmonics was observed, respectively. We also demonstrate experimentally that radiation pulses generated by each electron micro-bunch interfere coherently with the maximum intensity of cSPr observed at the frequency equal to the frequency of the micro-bunch spacing. The experimental results greatly contribute to the understanding of coherent Smith-Purcell radiation from the train of electron micro-bunches, as well as the development of THz diagnostics for accelerators.

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Enhancement of Coherent THz Smith-Purcell Radiation by Resonance Overlapping

Cited by 4 publications

References 31 publications

An electromagnetic simulation assisted small signal modeling method for InP double-heterojunction bipolar transistors

An electromagnetic simulation assisted small signal modeling method for InP double-heterojunction bipolar transistors

Novel configuration of aperture-type terahertz near-field imaging probe

Selective excitation and control of coherent terahertz Smith-Purcell radiation by high-intensity period-tunable train of electron micro-bunches

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