DESIGN AND SYNTHESIS OF CUTOFF FILTER USING PHOTONIC BANDGAP MATERIALS

2004 ◽  
Vol 11 (06) ◽  
pp. 607-614
Author(s):  
R. K. MISHRA ◽  
K. D. MISRA ◽  
R. P. PANDEY ◽  
R. P. TIWARI
Keyword(s):  
Periodic Structures ◽  
Transmission Band ◽  
Base System ◽  
Design And Synthesis ◽  
Photonic Bandgap Materials ◽  
Transfer Matrix Approach ◽  
Ideal Filter ◽  
Maximum Transmission ◽  
Cutoff Filter ◽  
The Ideal

In this paper, the design of a long and short wavelength cutoff filter using three-component periodic structure is presented. It is predicted that the manipulation of layers to obtain maximum transmission in three-component periodic structures are more suitable than two-component periodic structures. It is demonstrated that periods up to 22 bring maximum transmission with less oscillation within the high transmission band. Calculation for bandwidth is presented using the transfer matrix approach. It is suggested that for making the ideal filter, the optimization of layers with the three-component base system should be the best option for obtaining a desired transmission.

scholarly journals Procedure of definition of structure and parameters of multi-band matching circuits on the basis of intracavitary complex criterion for conformity to the ideal filter

Doklady BGUIR ◽  
2020 ◽  
Vol 18 (4) ◽  
pp. 62-70
Author(s):  
V. N. Shashok ◽  
A. S. Kanaplizki
Keyword(s):  
Transmission Band ◽  
Parametric Synthesis ◽  
Band Frequency ◽  
Integrated Method ◽  
Serial Connection ◽  
Complex Criterion ◽  
Ideal Filter ◽  
Frequency Selective ◽  
The Ideal ◽  
Multi Band

The article gives the procedure of structurally parametric synthesis of multi-band frequency-selective circuits. A short characteristic of approaches to solve the problems of synthesis of the multi-band frequencyselective circuits based on the use of multifrequency resonators, frequency transformations and parametric transformations using numerical procedures of optimisation is given. The research presents a short description of three widely used estimation criteria of the characteristics of frequency-selective circuits: Taylor, Chebyshev and average-degree criteria. Expedients of an estimate of joint approximation of amplitude-frequency and phasefrequency characteristics of synthesized circuits to those of the ideal filter are shown. The criterion is suggested and the procedure is presented for structurally parametrical synthesis of multi-band matching circuits on the basis of intracavitary complex criterion of conformity to the ideal filter in a transmission band and interband Chebyshev criterion realized by numerical optimization of synthesized circuits relative to the chosen criterion for affinessy is given. With that, the multi-band circuit is represented in form of a ladder-type connection that, generally, consists of n different reactive resistances. The example of using the proposed procedure to solve the problem of structurally parametric synthesis of a two-band matching circuit is given. As a matching load we selected the first-type equivalent consisting of a serial connection of active resistance and capacity. In the example there is an additional requirement to ensuring interband frequency selectivity. Such requirement is ensured by introducing zero to the function of transmission of the synthesized circuit on an interband average geometric frequency. The requirement is implemented by introducing a parallel oscillating circuit to the first serial arm of the synthesized circuit. The structurally parametric synthesis of the two-band matching circuit selected in the example is carried out through Mathcad 15 software based on the integrated method of Levenberg-Marquardt optimization.

Detection of Transients in Vibration Signals using Reverse Dispersion Entropy

2021 ◽  
pp. 1-33
Author(s):  
Jaafar Alsalaet
Keyword(s):  
Shannon Entropy ◽  
Vibration Signal ◽  
Fir Filter ◽  
Frequency Resolution ◽  
Frequency Bandwidth ◽  
Vibration Signals ◽  
Spectral Kurtosis ◽  
Ideal Filter ◽  
Envelope Signal ◽  
The Ideal

Abstract In this work, the reverse dispersion entropy (RDE) is used to process the squared envelope signal in order to detect nonstationarites. Based on the idea of spectral kurtosis (SK) and kurtogram, the squared envelope signal is first extracted by applying STFT to vibration signal. Then, as an alternative to negative Shannon entropy, the RDE is used to process the squared envelope to detect the range of frequencies at which the transients occur. The RDEgram color-coded map is used to represent the RDE values as a function of frequency and frequency resolution from which the ideal filter parameters can be inferred. Once, the best frequency and frequency bandwidth pair are found, an optimum FIR filter can be designed to filter the original vibration signal. The proposed method is tested against simulated and actual vibration signals and proved to be superior to existing methods.

Optimization of Filter Properties for Recirculating Etch Baths

2000 ◽  
Vol 43 (3) ◽  
pp. 30-40 ◽  
Author(s):  
Wayne Kelly ◽  
Donald Grant ◽  
Joseph Zahka
Keyword(s):  
High Efficiency ◽  
Polystyrene Latex ◽  
Capture Efficiency ◽  
Particle Capture ◽  
Membrane Filters ◽  
High Particle ◽  
Ideal Filter ◽  
Surface Modified ◽  
And Diffusion ◽  
The Ideal

Membrane filters are often used to remove small particles from liquids in recirculating etch baths (REBs). The ideal filter for this application would have both high particle capture efficiency and high flow permeability. Unfortunately, filters with high particle capture efficiency often have low permeability because the dominant particle capture mechanism is mechanical sieving. This paper describes more efficient capture mechanisms, interception and diffusion, and a filter with a surface modified to capture particles by these mechanisms. The filter has the same permeability as a conventional 0.45-μm filter and retains particles more efficiently than a conventional 0.05-μm filter. The filter is capable of removing multiple types of small (0.065-μm) particles (polystyrene latex, silicon nitride, alumina, etc.) with high efficiency (> 99.9 percent).

Polynomial Chebyshev Approximations of the Ideal Filter

1968 ◽  
Vol 15 (4) ◽  
pp. 307-315 ◽  
Author(s):  
L. Crousel ◽  
J. Neirynck
Keyword(s):  
Ideal Filter ◽  
The Ideal

scholarly journals Reconstruction of the Image Metric of Periodic Structures in an Opto-Digital Angle Measurement System

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4411
Author(s):  
Alexander N. Korolev ◽  
Alexander Ya. Lukin ◽  
Yurii V. Filatov ◽  
Vladimir Yu. Venediktov
Keyword(s):  
Periodic Structures ◽  
Angular Position ◽  
Digital Camera ◽  
Angle Measurement ◽  
Camera System ◽  
Optical Pattern ◽  
Image Metric ◽  
The Ideal ◽  
Camera Sensor

Measurement of the object angular position and its change is one of the important tasks in measurement technique. Our method is based on determination of the angular position of a 2D periodical optical pattern (2D mark) at the object, captured by the sensor of a digital camera. System performance can be frustrated by errors in determination of the spot coordinates on the camera sensor; by the presence of lens aberrations; by deviations from the parallelism of the pattern planes and the camera sensor; and by differences between the actual spots positions and the ideal grid. In the paper we discuss the effect of these errors and the way to correct or eliminate them. We have developed the mathematical routine and the corresponding numerical codes for correction of the said errors. The code and the routine we checked in a real experiment. It has shown that the correction decreases the standard deviation in 15 times.

Dynamics of Disordered Periodic Structures

1996 ◽  
Vol 49 (2) ◽  
pp. 57-64 ◽  
Author(s):  
Y. K. Lin
Keyword(s):  
Wave Propagation ◽  
Frequency Response ◽  
Periodic Structures ◽  
Dynamic Properties ◽  
Periodic Pattern ◽  
Structural System ◽  
Space Antenna ◽  
Spatially Periodic ◽  
Main Construction ◽  
The Ideal

For functional or aesthetic reasons, many a structural system is designed to be spatially periodic; namely, it is composed of identical sub-units which are connected to form a spatially periodic pattern. The main construction of the hull of a ship, the fuselage of an aircraft, and a space antenna are examples. Such a structure possesses interesting dynamic properties. However, due to material, geometric and manufacturing variabilities, an ideally periodic structure does not exist. The departure from the ideal designed configuration is known as disorder, which can cause drastic change in the dynamic behavior. The present paper gives a review of some recent works on wave propagation and frequency response of disordered periodic structures, of interest to researchers on vibration and noise control.

Optical Properties of Non-Periodic Dielectric Systems Made of Nanostructured Porous Silicon

2009 ◽  
Vol 5 ◽  
pp. 69-78 ◽  
Author(s):  
B. Alvarado Tenorio ◽  
J. Escorcia-Garcia ◽  
Miguel Eduardo Mora-Ramos ◽  
V. Agarwal
Keyword(s):  
Optical Properties ◽  
Porous Silicon ◽  
Optical Thickness ◽  
Periodic Structures ◽  
Period Doubling ◽  
Interference Filters ◽  
Transfer Matrix Approach ◽  
Multilayered Systems ◽  
Random Structures ◽  
Silicon Based

To investigate the optical properties in non-periodic dielectric systems, we study here the reflection of light from nanostructured porous-silicon-based period doubling heterostructures. The multilayered systems are fabricated in such a way that the optical thickness of each layer is one quarter of 650nm. The results for the optical reflectance are presented and compared with that of Fibonacci, Thue-Morse, and random structures fabricated under the same conditions. Numerical simulation for the reflectance along the lines of the transfer matrix approach is performed. In addition, optical reflection from Gaussian porous silicon multilayers is also briefly discussed. We find that porous silicon Period Doubling dielectric multilayers could demonstrate the optical properties similar to the classical periodic Febry-Perot interference filters with one or multiple resonant peaks, but with an advantage of having total optical thickness much lesser than that of the periodic structures.

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