Improved Rectification Performance and Terahertz Detection in Hybrid Structure of Self-Switching Device (SSD) and Planar Barrier Diode (PBD) Using Two-Dimensional Device Simulation

2020 ◽  
Vol 301 ◽  
pp. 111-117
Author(s):  
Nor Farhani Zakaria ◽  
Shahrir Rizal Kasjoo ◽  
Muammar Mohamad Isa ◽  
Zarimawaty Zailan ◽  
Mohd Khairuddin Md Arshad ◽  
...  
Keyword(s):  
High Frequency ◽  
Hybrid Structure ◽  
Terahertz Frequency ◽  
High Frequency Signal ◽  
Zero Bias ◽  
Switching Device ◽  
First Order ◽  
Fast Switching ◽  
Terahertz Detection ◽  
Parallel Configuration

Recently, simulations of In0.48Ga0.52As-based Planar Barrier Diode (PBD) and Self-Switching Device (SSD) as millimeter-wave rectifiers were reported. Both PBD and SSD have a planar structure, but with different insulating shapes and working principles. In this work, a hybrid structure of the reported PBD and SSD in a parallel configuration is proposed, to exploit the advantages of each device. The advantages of high rectifying properties in the SSD and fast switching rate of the PBD are combined in this hybrid structure in order to obtain an improved rectification performance at zero-bias in the near terahertz frequency region. Analysis of the curvature co-efficient, γ, which is defined as the ratio of the second order to the first order derivative of the device’s I-V function was performed to evaluate the rectification performance. AC transient analyses were then executed in various frequencies to imitate the high-frequency signal inputs. By using this hybrid structure, the highest value of γ achieved has been improved to ~19 V-1 at 70 mV, and ~6 V-1 at zero-bias (compared to the previous results on PBDs). The estimated cut-off frequency obtained was ~360 GHz (0.36 THz), operating at zero-bias.

scholarly journals Re-Design of Machine Tool Joint Components Based on Polymer Fillings for High-Speed Performance

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6913
Author(s):  
Zuzana Murčinková ◽  
Pavel Adamčík ◽  
Jozef Živčák
Keyword(s):  
Acoustic Emission ◽  
High Frequency ◽  
High Speed ◽  
Dynamic Properties ◽  
Hybrid Structure ◽  
Particulate Composites ◽  
High Frequency Signal ◽  
Structural Modifications ◽  
Speed Performance

In this paper, we report the results of an experimental study of a re-design approach using filling polymers and particulate composites with a polymer matrix, thus creating a macroscopic hybrid structure. The re-design is focused on the joint of a textile machine. It is a re-design of already existing machine parts of a joint in order to increase the damping of components, reduce the amplitudes of high-frequency vibrations and acoustic emission for high-speed operation of textile rotors, and to compare individual structural modifications of the rotor housing body and absorber of high-speed textile rotor in a spinning unit with respect to dynamic properties of that measured mechanical system. The experiments included a bump test, determination of logarithmic decrement, measurement of vibration acceleration, a wavelet analysis, and measurement of acoustic emission. When excited by high frequency signal amplitudes up to 5 g, the benefits of polymer filling were manifested by an approximately 50% reduction in amplitude vibrations, a 66% reduction in acoustic emission amplitude, and an 85% reduction of the maximum peak in the acoustic emission FFT spectrum. In the area above 10 g, the stiffness of the component dominated to reduce the magnitude of vibrations.

HIGH FREQUENCY OHMIC LOSSES IN TERAHERTZ FREQUENCY RANGE CW KLYNOTRONS

2017 ◽  
Vol 76 (10) ◽  
pp. 929-940 ◽  
Author(s):  
Yu. S. Kovshov ◽  
S. S. Ponomarenko ◽  
S. A. Kishko ◽  
A. A. Likhachev ◽  
S. A. Vlasenko ◽  
...  
Keyword(s):  
High Frequency ◽  
Terahertz Frequency ◽  
Frequency Range ◽  
Terahertz Frequency Range ◽  
Ohmic Losses

Dither in a rolling airframe flight vehicle with a two-position actuator: An amplitude distribution approach

2016 ◽  
Vol 39 (8) ◽  
pp. 1205-1215 ◽  
Author(s):  
Bahram Mohammadi ◽  
Mohammad Reza Arvan ◽  
Yousof Koohmaskan
Keyword(s):  
High Frequency ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Cross Coupling ◽  
Amplitude Distribution ◽  
Feedback System ◽  
Flight Vehicle ◽  
Frequency Signal ◽  
High Frequency Signal ◽  
Minimal Error

Rolling airframe manoeuvring is a type of manoeuvre in which the missile provides continuous roll during flight. Cross-coupling between the angle of attack and sideslip in rolling airframe missiles (RAMs) yields a coning motion around the flight path. As the pitch and yaw cross-coupling effect decreases, the radius of this coning motion decreases and the accuracy of the control system increases. Two-position (on–off) actuators are used in most RAMs. The presence of a two-position actuator in a feedback system makes its characteristics non-linear. A high-frequency signal so-called dither is applied to compensate for the non-linearity effect of the actuator characteristic in the feedback system and to stabilize the coning motion. The amplitude distribution function (ADF) method in dither analysis shows that the smoothed non-linearity characteristic can be computed as the convolution of the original non-linearity and the ADF of the dither signal. According to the four-degrees-of-freedom (4-DOF) equations of RAMs in a non-rolling frame and regarding various dither signals through the ADF approach on a two-position actuator, an analytical condition for dither amplitude in coning motion stability of RAMs is derived. It was shown that the triangular signal with specified amplitude and high enough frequency led to a smoother response of two-position actuators. Finally, by applying beam-riding guidance to a RAM, the performance of dithers for decreasing the distance of the missile from the centre of the beam is validated through simulations. It is illustrated that applying the triangular dither resulted in minimal error.

Efficient Synthesis and Photochromic Properties of a New Diarylethene Bearing a Condensed Aromatics Moiety

2012 ◽  
Vol 455-456 ◽  
pp. 33-36
Author(s):  
Ren Jie Wang ◽  
Hong Ying Xia ◽  
Gang Liu ◽  
Shi Qiang Cui
Keyword(s):  
Uv Light ◽  
Optical Storage ◽  
Hybrid Structure ◽  
Order Reaction ◽  
Pmma Film ◽  
Efficient Synthesis ◽  
Photochromic Properties ◽  
First Order ◽  
New Class ◽  
Hexane Solution

A new class of diarylethenes based on a hybrid structure of thiophene and naphthalene has been developed and its properties including photochromism, kinetics and fluorescence were investigated in detail. The results showed that the compound exhibited obvious photochromism, changing from colorless to red after irradiation with 297 nm UV light both in solution and in PMMA film. The kinetic experiments indicated that the cyclization/cycloreversion process of the compound was determined to be the zeroth/first order reaction in hexane solution. At last, the results demonstrated that the diarylethene compound had attractive properties for potential application in optical storage.

Evaluation of sampling alternatives to quantify tree leaf area

2003 ◽  
Vol 33 (1) ◽  
pp. 82-95 ◽  
Author(s):  
H Temesgen
Keyword(s):  
Leaf Area ◽  
Poor Performance ◽  
Tree Crown ◽  
Two Stage ◽  
Zero Bias ◽  
Probability Sampling ◽  
First Order ◽  
Unequal Probability Sampling ◽  
Unequal Probability ◽  
Tree Leaf

High within- and among-tree crown variation have contributed to the difficulty of tree-crown sampling and single-tree leaf area (area available for photosynthesis) estimation. Using reconstructed trees, simulations were used to compare five sampling designs for bias, mean square error (MSE), and distribution of the estimates. All sampling designs showed nearly zero bias. For most sample trees, stratified random sampling resulted in the lowest MSE values, followed by ellipsoidal, two-stage systematic, simple random, and then by two-stage unequal probability sampling. The poor performance of two-stage unequal probability sampling can be ascribed to the unequal probability of inclusion of first-order branches and twigs.

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