Papers by Keyword: Waveguide

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Authors: Jiang An Han, Jun Xu
Abstract: A novel millimeter-wave transition from microstrip to rectangular waveguide is introduced in this paper. The theory for this design is explained. The strip conductor on microstrip, which is introduced from the center of a rectangular waveguide broad-wall to its E-plane, is shaped into a triangular loop in the waveguide terminated by a short circuit. A back to back transition operating at Ka band was simulated and fabricated. The experimental results showed the insertion loss of a back to back transition is less than 2.2dB with its return loss greater than 9.1dB from 26.5 GHz to 35.5 GHz.
Authors: Fei Zhao, Chang Tao Sha, Gang Zhao, Ke Wang, Jin Song Kan
Abstract: A one-port waveguide method and related apparatus based on the multi-state techniques is descried in this paper. This method measures only the magnitude and phase information for the reflection coefficients of four-state before and after the samples under test being loaded. On the basis of such data, the complex permittivity and permeability of the samples can be simultaneous calculated by software programmed according to the related theories discussed herein. In addition, the error analysis is also discussed in this paper. The proposed method is applicable to measure magnetic and/or medium-to high-loss materials, hence it is suitable to characterize the properties of radar absorbing materials.
Authors: T. Chantakit, S. Kamoldilok, K. Srinuanjan, P.P. Yupapin
Abstract: The effective numerical aperture calculation in two-dimensional Photonic crystal waveguide has been proposed. In this paper we present the analysis of ray optics refracted inside nanorods and at the boundaries between rods, which separates rod gap is much smaller than the incident wavelength assumed to reflect on the region. In operation, the resolving numerical aperture was compared with the finite difference time domain method via OptiFDTD software. Although numerical aperture mentioned above was found to be extremely close to fiber optics, a transmission passes though compartments of the rods are observed due to significant estimation of transmission and reflection of electric field. The compared simulation results will be discussed. By the aforementioned is that in the near future we will modify wave equation in periodic media of waveguide structures reached to the transverse electric equation of beam propagation in the two-dimensional Photonic crystal waveguide analysed.
Authors: Jie Qing Fan, Jian Hong Hao, Zi Xian Song, Xue Fen Liu
Abstract: The equivalent circuit model of shielding effectiveness of the cylindrical cavity with apertures against the near-field waves of electric dipole is established. The analytical formulas for approximately calculating the shielding effectiveness are given by the adjusted transmission line method. It is shown that the near-field shielding effectiveness of a cylindrical cavity with apertures is far inferior to that of far-field. The near-filed SE of the cylindrical cavity increases with the distance between the diploe and the apertured cavity, but when the distance is greater than a half wavelength of the electromagnetic disturbances, the SE tends to be saturated. In the cavity, the electric SE increased with the distance of observation points to the apertures. Results of the adjusted TLM are in good agreement with the CST simulation results.
Authors: Hong Wei Yang, Lian Chun Long
Abstract: In this paper, precise integration in a symplectic system is used to analyze the stop-band characteristic of the dielectric layer PBG structure in a waveguide. The transverse section is made discrete by using edge elements. The stiff matrices of a dielectric layer and an air layer can be calculated by precision integration based on Riccati equations in a Hamiltonian system. The export stiff matrices of a period can be obtained by a combination of substructures, and then the whole structure can be solved. The stop-band characteristic of a dielectric layer PBG structure in a waveguide is obtained and the effects of the size of period and the number of periods are discussed. The examples presented show that this method is precise and efficient.
Authors: Husain Mushahid, Raman Swati
Abstract: The present research work is focused on fabricating the chalcogenide glass optical waveguides keeping in mind their application in optical communication. The propagation loss of the waveguides is also studied at three different wavelengths. The waveguides were fabricated by dry etching using ECR Plasma etching and the propagation loss is studied using Fabry-Perot technique. The waveguides having loss as low as 0.35 dB/cm at 1.3m is achieved. The technique used to fabricate waveguide is simple and cost effective.
Authors: Hyun Se Kim, Yang Lae Lee, Eui Su Lim
Abstract: A near-field megasonic system for cleaning semiconductors was designed and fabricated. For the design of the near-field megasonic system, an impedance characteristic of a quartz megasonic waveguide with the piezoelectric actuator was analyzed using a finite element method (FEM). The analysis result showed that the anti-resonance frequency of the system was 982 kHz, which agreed well with the measured value of 988 kHz. The performance of the developed system was assessed by measuring acoustic pressures and comparing the maximim values of them with a conventional megasonic system. As a result, the maximim acoustic pressure of the developed system was decreased by 46.2% compared to the commercial system. Finally, the particle removal efficiency (PRE) test was performed and the obtained PRE was 90.8%. Theses results explain that the developed megasonic has an improved uniformity of the acoustic pressures, which can raise the energy efficiency of the system and lowering the consumption of chemical and ultra pure water (UPW).
Authors: P. Sreeramana Aithal, P. Mohan Rao, D.K. Avasthi
Authors: Milan Nad, Lenka Cicmancova
Abstract: mproving of cutting process is one of the most important requirements that are expected from the machining methods in the recent years. In some machining processes, the positive effect of ultrasonic waves to improve the cutting process is used. The cutting process efficiency depends on the structure of excitation system which generates ultrasonic waves. One of the most important elements of this system is the ultrasonic waveguide. The role of waveguide is the transfer of ultrasonic vibration energy from ultrasonic transducer to the tool cutting edge interacting with the workpiece (ultrasonic assisted machining-UAM). The UAM system performance depends on well-designed ultrasonic waveguide. The most important aspects of waveguide design are a resonant frequency, amplification factor and the determination of waveguide resonant wavelength - usually integer multiple of half wavelength. The effect of geometrical parameters of stepped waveguide on dynamical properties is presented in this paper.
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