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Design of a Dual-Band Rectangular Waveguide Filter based on Direct Coupled

Slimane Gouni, Mehdi Damou, Mohammed Chetioui, Abdelhakim Boudkhil

International Journal of Electronics and Telecommunications

2022

Vol. 68. No. 3

483--488

This paper presents how to design and simulate a passband rectangular waveguide filters based on direct coupled resonators operating at 12 GHz. The modeled filters are characterized by a cross coupling that produces a single attenuation pole at finite frequency used to shape the bandpass response. Resonators provide bandpass filter designs with a pseudo-elliptic response using HFSS simulators. Transmission zeros are obtained through coupling between the fundamental mode and high mode. The filter structures are validated leading to obtain transmission zeros close to the passband. The simulated waveguide filters with a centre frequency exhibit an insertion loss of -0.4/0.3dB and a return loss of −20/23dB for a bandwidth ranging from 11.85GHz to 12.15GHz that shows good electromagnetic responses for the simulated filters.

Fluid–structure interaction vibration experiments and numerical verification of a real marine propeller

Lou Benqiang, Cui Hongyu

Polish Maritime Research

2021

nr 3

61--75

The design of lifting blade shapes is a key engineering application, especially in domains such as those of marine propellers, hydrofoils, and tidal energy converters. In particular, the excitation frequency must be different from that of the structure to avoid resonance. The natural frequency in the cases where the fluid–structure interaction (FSI) is considerably different if considering the coupling added mass (AM) of the water. In this study, vibration experiments were performed using a real propeller in air and water. The modal parameters, natural frequencies, and mode shapes were determined. Validations were performed using 3D solid and acoustic elements in a direct coupling finite element format. The modal results and AM ratios were in agreement with the experimental results. Convenient application and high efficiency are basic requirements for an engineering application. Therefore, an empirical formula was established for the first-order FSI natural frequency to enable rapid estimation, thereby satisfying this requirement.

Solution of some problems of single-scale wavelet transform processor using a magnetostatic surface wave device

Lu W., Kuang L., Lü X., Zhu C., Zhang T., Zhang J.

Metrology and Measurement Systems

2012

Vol. 19, nr 4

685-692

In this paper, we investigate the implementation schemes of a single-scale wavelet transform processor using magnetostatic surface wave (MSSW) devices. There are three implementation schemes: the interdigital transducer, the meander line transducer and the grating transducer. Because the interdigital transducer has excellent properties, namely, good frequency characteristic and low insertion loss, we use the interdigital transducer as the implementation scheme of a single-scale wavelet transform processor using MSSW device. In the paper, we also present the solutions to the three key problems: the direct coupling between the input transducer and the output transducer, the insertion loss, and the loss characteristics of the gyromagnetic film having an influence on the wavelet transform processor. There are two methods of reducing the direct coupling between the input transducer and the output transducer: increasing the distance between the input transducer and the output transducer, and placing a metal "wall" between the input transducer and the output transducer. There also are two methods of reducing the insertion loss of a single-scale wavelet transform processor using a MSSW device for scale: the appropriate thickness of the yttrium iron garnet (YIG) film and the uniform magnetic field. The smaller the ferromagnetic resonance linewidth of the gyromagnetic film, the smaller the magnetostatic wave propagation loss.