scholarly journals Design aspects of Bi2Sr2CaCu2O8+δ THz sources: optimization of thermal and radiative properties

2021 ◽  
Vol 12 ◽  
pp. 1392-1403
Author(s):  
Mikhail M Krasnov ◽  
Natalia D Novikova ◽  
Roger Cattaneo ◽  
Alexey A Kalenyuk ◽  
Vladimir M Krasnov
Keyword(s):  
Experimental Data ◽  
Power Efficiency ◽  
Open Space ◽  
Radiation Power ◽  
Impedance Matching ◽  
Dipole Antenna ◽  
Radiative Properties ◽  
Heat Management ◽  
Order Of Magnitude ◽  
Good Agreement

Impedance matching and heat management are important factors influencing the performance of terahertz sources. In this work we analyze thermal and radiative properties of such devices based on mesa structures of a layered high-temperature superconductor Bi2Sr2CaCu2O8+δ. Two types of devices are considered containing either a conventional large single crystal or a whisker. We perform numerical simulations for various geometrical configurations and parameters and make a comparison with experimental data for the two types of devices. It is demonstrated that the structure and the geometry of both the superconductor and the electrodes play important roles. In crystal-based devices an overlap between the crystal and the electrode leads to appearance of a large parasitic capacitance, which shunts terahertz emission and prevents impedance matching with open space. The overlap is avoided in whisker-based devices. Furthermore, the whisker and the electrodes form a turnstile (crossed-dipole) antenna facilitating good impedance matching. This leads to more than an order of magnitude enhancement of the radiation power efficiency in whisker-based, compared to crystal-based, devices. These results are in good agreement with presented experimental data.

scholarly journals Design aspects of Bi2Sr2CaCu2O8+δ THz sources: optimization of thermal and radiative properties

2021 ◽  
Author(s):  
Mikhail M Krasnov ◽  
Natalia D Novikova ◽  
Roger Cattaneo ◽  
Alexey A Kalenyuk ◽  
Vladimir M Krasnov
Keyword(s):  
Experimental Data ◽  
Power Efficiency ◽  
Open Space ◽  
Radiation Power ◽  
Impedance Matching ◽  
Dipole Antenna ◽  
Radiative Properties ◽  
Heat Management ◽  
Order Of Magnitude ◽  
Thz Sources

Impedance matching and heat management are important factors influencing performance of THz sources. In this work we analyze thermal and radiative properties of such devices based on mesa structures of a layered high-temperature superconductor Bi2Sr2CaCu2O8+δ. Two types of devices are considered, containing either a conventional large single crystal, or a whisker. We perform numerical simulations for various geometrical configurations and parameters and make a comparison with experimental data for the two types of devices. It is demonstrated that the structure and the geometry of both the superconductor and the electrodes are playing important roles. In crystal-based devices an overlap between the crystal and the electrode leads to appearance of a large parasitic capacitance, which shunts THz emission and prevents impedance matching with open space. The overlap is avoided in whisker-based devices. Furthermore, the whisker and the electrodes form a turnstile (crossed-dipole) antenna facilitating good impedance matching. This leads to more than an order of magnitude enhancement of the radiation power efficiency in whisker-based, compared to crystal-based devices. These results are in good agreement with presented experimental data.

The Formation of Molecules in Three Atom Collisions using the Eikonal Approximation

1976 ◽  
Vol 31 (12) ◽  
pp. 1489-1499
Author(s):  
E. Czuchaj
Keyword(s):  
Experimental Data ◽  
Numerical Calculation ◽  
Rate Constant ◽  
Recombination Rate ◽  
Eikonal Approximation ◽  
New Approach ◽  
Order Of Magnitude ◽  
Recombination Rate Constant ◽  
Good Agreement

Abstract A new approach to the calculation of a teratomic recombination rate constant k(T) has been dem-onstrated. An expression for k(T) has been obtained in the eikonal approximation. The numerical calculation has been carried out for the Rb*-Xe system. Good agreement in the order of magnitude between the present results and the experimental data of Carrington et al. has been obtained.

Elliptical Annular Slot Loaded Trapezoidal Dipole Antenna for Band-Notched UWB Applications

2016 ◽  
Vol 12 (1) ◽  
pp. 23-29
Author(s):  
Sarthak Singhal ◽  
Nand Verma ◽  
Amit Singh
Keyword(s):  
Impedance Matching ◽  
Dipole Antenna ◽  
Frequency Range ◽  
Entire Frequency Range ◽  
Antenna Structure ◽  
Annular Slot ◽  
Notched Band ◽  
Uwb Applications ◽  
Peak Gain ◽  
Good Agreement

In this paper, a semi-elliptical annular slot loaded trapezoidal dipole antenna with band-notched characteristics for UWB applications is designed. A microstrip feedline consisting of multiple feedline sections is used for improving the impedance matching. The band-notched characteristics for WLAN band are achieved by loading the trapezoidal dipole arms with semi-elliptical annular slots. The designed antenna structure has an operating range from 3.5-12.4 GHz(109%) with band-rejection in the frequency range of 5-6 GHz. Nearly omnidirectional patterns are achieved for the designed antenna structure. The designed antenna structure provided an average peak gain of 2.12 dB over the entire frequency range except in the notched band where it reduced to -2.4 dB. The experimental and simulation results are observed to be in good agreement. An improved bandwidth performance with miniaturized dimensions as compared to earlier reported antenna structures is achieved.

Hex-Sided Rounded Dipole Antenna (HSRDA) For UWB Applications

Frequenz ◽  
2016 ◽  
Vol 70 (3-4) ◽  
Author(s):  
Sarthak Singhal ◽  
Nand Kishor Verma ◽  
Amit Kumar Singh
Keyword(s):  
Impedance Matching ◽  
Dipole Antenna ◽  
Impedance Bandwidth ◽  
Radiation Patterns ◽  
Frequency Range ◽  
Antenna Structure ◽  
Simulation Results ◽  
Uwb Applications ◽  
Bow Tie ◽  
Good Agreement

AbstractA hex-sided rounded dipole antenna (HSRDA) for UWB applications is presented. It is designed by the addition of semi-elliptical patch sections at the edges of a square bow-tie antenna. The antenna structure is fed by a modified microstrip feedline for better impedance matching. An impedance bandwidth of 2.9–11.4 GHz is achieved. The antenna structure has quasi omnidirectional radiation patterns and reasonable gain over the same frequency range. A good agreement between the experimental and simulation results is observed. The proposed antenna structure has miniaturized size for the same bandwidth as compared to already reported antenna structures.

scholarly journals Broadband Dual-Polarized Loop Cross-Dipole Antenna for 5G Base Station Applications

Electronics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 1574
Author(s):  
Chenyang Liao ◽  
Bin Wang ◽  
Congcong Zhu ◽  
Honggang Hao ◽  
Bo Yin
Keyword(s):  
Impedance Matching ◽  
Equivalent Circuit Model ◽  
Beam Width ◽  
Dipole Antenna ◽  
Base Station ◽  
Flow Diagram ◽  
Cross Polarization ◽  
Dual Polarized ◽  
Half Power ◽  
Good Agreement

A broadband dual-polarized base station antenna is proposed in this paper. The antenna consists of loop cross-dipoles, Y-shaped coupling feeding lines, and a metal box reflector. An equivalent circuit model including a signal flow diagram is established to analyze the mechanism of the proposed antenna in detail. Moreover, the Y-shaped coupling feeding lines are introduced to control the coupling with the antenna to achieve broadband and good impedance matching. The prototype of the antenna is fabricated and measured. The measured results show that the antenna with simple structures can operate at the band of 3.2–5.22 GHz (48%) with high port-to-port isolation (35 dB) and stable gain (9 ± 1 dBi). The measured results show good agreement with simulated results, especially in cross-polarization discrimination ratio (>27 dB) and the half power beam width (61° ± 3° at the E-plane, 68° ± 3° at the H-plane). In summary, the proposed antenna could be a good candidate for 5G sub-6 GHz base station applications.

Two-Phase Flow Patterns in a Square Micro-Channel

2003 ◽  
Author(s):  
Jian-Fu Zhao ◽  
Bin Li
Keyword(s):  
Experimental Data ◽  
Two Phase Flow ◽  
Flow Patterns ◽  
Bond Number ◽  
Phase Flow ◽  
Micro Channel ◽  
Two Phase ◽  
Scale Modeling ◽  
Order Of Magnitude ◽  
Good Agreement

A new set of experimental data of two-phase air-water flow patterns in a square micro-channel is presented. The channel has a cross-section of 1×1 mm2 and a length of 300 mm. The ranges of the gas and liquid superficial velocities are 0.1–10 m/s and 0.2–7 m/s, respectively. Bubble, bubbleslug transitional, slug, and frothy patterns are observed. The present data are compared with other experimental data reported in the literature, and a good agreement is obtained. It is also compared the present data with those obtained from reduced gravity experiments, in which the Bond number has the same order of magnitude. Some problems associated with the micro-scale modeling of microgravity two-phase flow are also discussed.

Energy Levels and Electromagnetic Transition of 90-94mo Nuclei Using Ibm-1

2020 ◽  
pp. 149-152
Keyword(s):  
Experimental Data ◽  
Transition Probability ◽  
Energy Levels ◽  
Dynamical Symmetry ◽  
Interacting Boson Model ◽  
Excitation Energies ◽  
Electromagnetic Transition ◽  
Boson Model ◽  
Energy States ◽  
Good Agreement

The energy states for the J , b , ɤ bands and electromagnetic transitions B (E2) values for even – even molybdenum 90 – 94 Mo nuclei are calculated in the present work of "the interacting boson model (IBM-1)" . The parameters of the equation of IBM-1 Hamiltonian are determined which yield the best excellent suit the experimental energy states . The positive parity of energy states are obtained by using IBS1. for program for even 90 – 94 Mo isotopes with bosons number 5 , 4 and 5 respectively. The" reduced transition probability B(E2)" of these neuclei are calculated and compared with the experimental data . The ratio of the excitation energies of the 41+ to 21+ states ( R4/2) are also calculated . The calculated and experimental (R4/2) values showed that the 90 – 94 Mo nuclei have the vibrational dynamical symmetry U(5). Good agreement was found from comparison between the calculated energy states and electric quadruple probabilities B(E2) transition of the 90–94Mo isotopes with the experimental data .

Predicting the Effect of Tire Tread Pattern Design on Thick Film Wet Traction

1977 ◽  
Vol 5 (1) ◽  
pp. 6-28 ◽  
Author(s):  
A. L. Browne
Keyword(s):  
Experimental Data ◽  
Network Design ◽  
Thick Film ◽  
Digital Computer ◽  
Analytical Tool ◽  
Design Practice ◽  
Pattern Design ◽  
Performance Results ◽  
Good Agreement

Abstract An analytical tool is presented for the prediction of the effects of changes in tread pattern design on thick film wet traction performance. Results are reported for studies in which the analysis, implemented on a digital computer, was used to determine the effect of different tread geometry features, among these being the number, width, and lateral spacing of longitudinal grooves and the angle of zigzags in longitudinal grooves, on thick film wet traction. These results are shown to be in good agreement with experimental data appearing in the literature and are used to formulate guidelines for tread groove network design practice.

A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

2015 ◽  
Vol 11 (3) ◽  
pp. 3224-3228
Author(s):  
Tarek El-Ashram
Keyword(s):  
Experimental Data ◽  
Brillouin Zone ◽  
Electron Concentration ◽  
Free Electron ◽  
Lattice Point ◽  
Valence Electron ◽  
Fermi Gas ◽  
Valence Electron Concentration ◽  
Fermi Sphere ◽  
Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;𝑽𝑭𝑽𝑩= 𝒏𝑽𝑬𝑪𝟐for all crystalline systems (wheren is the number of atoms per lattice point).

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