Study on Resonant Properties for HE111 Mode of Complicated Microwave Cavity in Rubidium Frequency Standard under Different Parameters

2013 ◽  
Vol 373-375 ◽  
pp. 981-985
Author(s):  
Xiao Xiao Li ◽  
Shang Lin Hou ◽  
Jing Li Lei
Keyword(s):  
Resonant Frequency ◽  
Frequency Standard ◽  
Microwave Cavity ◽  
Matching Method ◽  
Complicated Structure ◽  
Resonant Frequencies ◽  
Cavity Design ◽  
Main Factors ◽  
High Credibility ◽  
Good Agreement

Microwave cavity with complicated structure and rubidium gas is studied by mode matching method. By calculating resonant frequencies of HE111mode under different parameters, main factors that influence resonant frequency is studied. In addition, the resonant frequency of HE111mode is compared with commercial software (CST) results. The computed results show good agreement with CST simulations. It can be seen that this method is of high credibility and efficiency. This paper is of great significance for cavity design and theoretical perfection.

Study on TE011 Mode’s Resonant Characteristic of Complicated Microwave Cavity with Ceramics Layer in Rubidium Frequency Standard

2012 ◽  
Vol 571 ◽  
pp. 137-142
Author(s):  
Xiao Xiao Li ◽  
Bin Zhao Cao
Keyword(s):  
Frequency Standard ◽  
Microwave Cavity ◽  
Mode Matching ◽  
Matching Method ◽  
Resonant Frequencies ◽  
Factors Influencing ◽  
Cavity Design ◽  
Main Factors ◽  
Resonant Characteristic ◽  
Good Agreement

Complicated microwave cavity loaded with ceramics is first investigated by mode matching method in rubidium frequency standard. In order to study main factors influencing resonant characteristics, resonant frequencies of TE011 mode are calculated and compared with commercial software (CST) results. The results show good agreement between theoretical computations and CST simulations. This work is of great significance for cavity design and theory perfection in atomic frequency standard.

TE0 Mode Resonant Properties of the Rubidium Clock Microwave Cavity Loaded with Ceramic Material

2013 ◽  
Vol 433-435 ◽  
pp. 2213-2217
Author(s):  
Xiao Xiao Li ◽  
Jin Li Lei ◽  
Guo Dong Ren
Keyword(s):  
Ceramic Material ◽  
Atomic Clock ◽  
Microwave Cavity ◽  
Matching Method ◽  
Resonant Frequencies ◽  
Factors Influencing ◽  
Rubidium Clock ◽  
New Type ◽  
Cavity Design ◽  
Main Factors

Resonant properties of a Microwave cavity with ceramic material for a new type of rubidium clock is studied by mode matching method. In order to study main factors influencing resonant characteristics, resonant frequencies of TE011 mode are calculated. In addition, the effect of the ceramic material on resonant frequency are also analyzed. This work is of great significance for cavity design and theory perfection in atomic clock.

scholarly journals Resonant Frequency of Circular Sectorial Microstrip Antenna Printed On Double-Layered Anisotropic Substrates

2021 ◽  
Author(s):  
Souad FRIHA ◽  
Sami Bedra ◽  
Fouad CHEBBARA ◽  
Randa BEDRA ◽  
Siham BENKOUDA
Keyword(s):  
Resonant Frequency ◽  
Computer Aided Design ◽  
Microstrip Antenna ◽  
Microstrip Antennas ◽  
Resonant Frequencies ◽  
Design Engineers ◽  
Anisotropic Substrates ◽  
Aided Design ◽  
Composite Substrates ◽  
Good Agreement

Abstract In this work, modal characteristics have been rigorously studied which germinate an improved, accurate, and efficient computer-aided design (CAD) formulation to estimate the resonant frequency of sectorial circular microstrip antennas printed on anisotropic suspended and composite substrates. The obtained results demonstrated that the resonant frequencies of the sectorial circular microstrip patch on suspended and composite substrates can be adjusted to obtain the maximum operating frequency of the antenna. The computed results show a fairly good agreement with measured results. Such theoretical validation and results may prove to be more useful for design engineers and further investigation.

Tire Vibrations

1977 ◽  
Vol 5 (4) ◽  
pp. 202-225 ◽  
Author(s):  
G. R. Potts ◽  
C. A. Bell ◽  
L. T. Charek ◽  
T. K. Roy
Keyword(s):  
Natural Frequencies ◽  
Standing Waves ◽  
Resonant Mode ◽  
Mode Shapes ◽  
Resonant Vibrations ◽  
Resonant Frequencies ◽  
Radial Tire ◽  
Analysis Techniques ◽  
Thin Ring ◽  
Good Agreement

Abstract Natural frequencies and vibrating motions are determined in terms of the material and geometric properties of a radial tire modeled as a thin ring on an elastic foundation. Experimental checks of resonant frequencies show good agreement. Forced vibration solutions obtained are shown to consist of a superposition of resonant vibrations, each rotating around the tire at a rate depending on the mode number and the tire rotational speed. Theoretical rolling speeds that are upper bounds at which standing waves occur are determined and checked experimentally. Digital Fourier transform, transfer function, and modal analysis techniques used to determine the resonant mode shapes of a radial tire reveal that antiresonances are the primary transmitters of vibration to the tire axle.

scholarly journals Piezoelectric MEMS Acoustic Transducer with Electrically-Tunable Resonant Frequency

Micromachines ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 96
Author(s):  
Alessandro Nastro ◽  
Marco Ferrari ◽  
Libor Rufer ◽  
Skandar Basrour ◽  
Vittorio Ferrari
Keyword(s):  
Acoustic Emission ◽  
Resonant Frequency ◽  
Piezoelectric Layer ◽  
Flexural Mode ◽  
Resonant Frequencies ◽  
Voltage Mode ◽  
Acoustic Transducer ◽  
Aln Film ◽  
Doped Silicon ◽  
Piezoelectric Mems

The paper presents a technique to obtain an electrically-tunable matching between the series and parallel resonant frequencies of a piezoelectric MEMS acoustic transducer to increase the effectiveness of acoustic emission/detection in voltage-mode driving and sensing. The piezoelectric MEMS transducer has been fabricated using the PiezoMUMPs technology, and it operates in a plate flexural mode exploiting a 6 × 6 mm doped silicon diaphragm with an aluminum nitride (AlN) piezoelectric layer deposited on top. The piezoelectric layer can be actuated by means of electrodes placed at the edges of the diaphragm above the AlN film. By applying an adjustable bias voltage Vb between two properly-connected electrodes and the doped silicon, the d31 mode in the AlN film has been exploited to electrically induce a planar static compressive or tensile stress in the diaphragm, depending on the sign of Vb, thus shifting its resonant frequency. The working principle has been first validated through an eigenfrequency analysis with an electrically induced prestress by means of 3D finite element modelling in COMSOL Multiphysics®. The first flexural mode of the unstressed diaphragm results at around 5.1 kHz. Then, the piezoelectric MEMS transducer has been experimentally tested in both receiver and transmitter modes. Experimental results have shown that the resonance can be electrically tuned in the range Vb = ±8 V with estimated tuning sensitivities of 8.7 ± 0.5 Hz/V and 7.8 ± 0.9 Hz/V in transmitter and receiver modes, respectively. A matching of the series and parallel resonant frequencies has been experimentally demonstrated in voltage-mode driving and sensing by applying Vb = 0 in transmission and Vb = −1.9 V in receiving, respectively, thereby obtaining the optimal acoustic emission and detection effectiveness at the same operating frequency.

scholarly journals THE STUDY OF ACOUSTIC CHARACTERISTICS OF THE PERFORATED AND HOMOGENOUS PLATES WITH SIMILAR GEOMETRICAL DIMENSIONS

Akustika ◽  
2019 ◽  
Vol 32 ◽  
pp. 79-82
Author(s):  
Valery Kirpichnikov ◽  
Lyudmila Drozdova ◽  
Alexei Koscheev ◽  
Ernst Myshinsky
Keyword(s):  
Resonant Frequency ◽  
Acoustic Radiation ◽  
Perforated Plate ◽  
Acoustic Characteristics ◽  
Resonant Frequencies ◽  
Perforated Plates ◽  
Resonance Frequencies ◽  
Flexural Vibrations ◽  
Geometrical Dimensions

The resonance frequencies of the flexural vibrations, input vibration excitability and acoustic radiation of the homogeneous and perforated plates were investigated. It is established that the average reduction range of the lower resonant frequency of flexural vibrations of the tested plates with the holes virtually coincides with the predictive estimate. The levels of the input vibration excitability of the perforated plate at the lower resonant frequencies exceeded the levels at the corresponding frequencies of the homogeneous plates greater than the calculated value. The levels of resonance acoustic radiation of the perforated plate were significantly less than of the homogeneous one.

Experimental Study on the Shear Properties of Concrete Column Repaired by CFRP

2012 ◽  
Vol 166-169 ◽  
pp. 1598-1602
Author(s):  
Xi Guang Cui ◽  
Zhi Wei Wang ◽  
Nan Ma ◽  
Zhong Long Yu
Keyword(s):  
Experimental Study ◽  
Concrete Columns ◽  
Concrete Column ◽  
Longitudinal Reinforcement ◽  
Simulation Data ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics ◽  
Main Factors ◽  
Good Agreement

In this paper, shear study was carried out on four reinforced concrete columns in which two columns were reinforced by CFRP (carbon fiber reinforced plastics). The three main factors: shear span ratio, ratio of longitudinal reinforcement, CFRP paste quantity (layer numbers) were analysied since they affect the reinforced effect of CFRP. Through the experiment and simulation, the results indicate that the shear strength of CFRP strengthened concrete columns is obvious, which shows good agreement with experimental and simulation data.

Robust Passive-Active Mounts for Machinery and Equipment

1997 ◽  
Author(s):  
J. Hannsen Su
Keyword(s):  
Resonant Frequency ◽  
Vibration Isolation ◽  
Vibration Suppression ◽  
Low Frequency ◽  
The Other ◽  
Resonant Frequencies ◽  
Vibration Magnitude ◽  
Fixed End ◽  
Degradation Problem ◽  
Universal Application

Abstract Conventional vibration isolation mounts are not as effective as expected on a practical foundation whose resonant frequencies normally are within the bandwidth of interest. In addition, the low frequency enhancement is a characteristic of the passive mounts. Applying inertia actuators to the bottom attachment plate of the conventional mounts overcomes these shortcomings and enhances their performance significantly. This design concept has universal application since it is applicable to any dynamic system. It requires very little power and force capacity, i.e., a small percentage of the disturbance force, from the actuators to be effective for frequencies higher than the resonant frequency of the mount itself. The effectiveness of the proposed mounts for the machinery is demonstrated on the load transmissibility reduction at the foundation support (fixed end) due to disturbance from machinery above mounts. On the other hand, the vibration magnitude reduction of equipment above mounts due to disturbance from the foundation is used for evaluating the equipment isolation effectiveness. There is no stabilty or degradation problem when a number of the passive-active mounts are used on the same foundation. Furthermore, the more of this type of mounts used on a foundation the more effective the vibration suppression and the smaller actuator force requirement for each passive-active mount.

Analysis of a circular microstrip antenna on isotropic or uniaxially anisotropic substrate using neurospectral approach

2013 ◽  
Vol 33 (1/2) ◽  
pp. 567-580 ◽  
Author(s):  
Sami Bedra ◽  
Siham Benkouda ◽  
Tarek Fortaki
Keyword(s):  
Resonant Frequency ◽  
Quality Factor ◽  
Microstrip Antenna ◽  
Numerical Results ◽  
Spectral Domain ◽  
Quality Factors ◽  
Resonant Frequencies ◽  
Content Type ◽  
Anisotropic Substrate ◽  
Circular Microstrip Antenna

Purpose – The paper aims to propose an artificial neural network (ANN) in conjunction with spectral domain formulation for fast and accurate determination of the resonant frequency and quality factor of circular microstrip antenna printed on isotropic or anisotropic substrate. This neurospectral approach reduces the problem complexity. Design/methodology/approach – The moment method implemented in the spectral domain provides good accuracy but its computational cost is high due to the evaluation of the slowly decaying integrals and the iterative nature of the solution process. The paper introduces the electromagnetic knowledge combined with ANN in the analysis of circular microstrip antenna on isotropic or uniaxially anisotropic substrate to reduce the complexity of the spectral approach and to minimize the CPU time necessary to obtain the numerical results. Findings – The resonant frequency results obtained from the neural model are in very good agreement with the experimental and theoretical results available in the literature. Finally, numerical results for the substrate anisotropy effect on the resonant frequency, quality factor and radiation pattern are also presented. Originality/value – The paper develops fast and accurate model based on ANN technique to calculate the resonant frequencies and quality factors of circular microstrip antennas. ANN is used to model the relationship between the parameters of the microstrip antenna and the resonant frequencies and quality factors obtained from the spectral domain approach. This relatively simple model allows designers to predict accurately the resonant frequencies and quality factors for a given design without having to develop or run the spectral method codes themselves. The main advantages of the method are: less computing time than the spectral model, results with accuracy equivalent to that of full-wave models and cost effectiveness, since the client can use a simple PC for implementation. Another advantage of the proposed ANN model is that it takes into account the uniaxial anisotropy in the substrate without increasing the network size. This is done by combining ANN with electromagnetic knowledge.

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