Development Of Microwave Devices Research Articles

The Influence of Mesh Granularity on the Accuracy of FEM Modelling of the Resonant State in a Microwave Chamber

Microwave technology is widely used in different areas of advanced industry when energy must be provided to water-containing and other materials. The main barrier in the development of microwave devices is the possibility of efficient design by modelling a microwave system in a resonant state. For technical systems, the finite element method is widely used. However, the convergence process in the microwave finite element solver is sophisticated. The process itself and the influence of mesh granularity on the accuracy of modelling of microwave chambers in resonant states have not been investigated previously. The present paper aims to fill this gap. The resonance conditions of a microwave chamber were tested from the point of view of spatial resolution of the tetrahedral mesh used for open-source ELMER FEM software. The presented results experimentally determine the limits of accuracy of the geometry of microwave resonant chamber finite element method-based models. The determined values of microwave resonant chamber dimension tolerances should be considered for both open-source and commercial software for microwave modelling.

A Variational Approach for Propagation in Ferromagnetic Nanowired Composite

This article presents a variational approach for ferromagnetic nanowired composites to determine material parameters, which are important for the development of microwave devices. It permits faster and easier calculation than numerical methods. The influence of ferromagnetic nanowires on the effective permittivity and the effective permeability is presented. For this purpose an analytical permittivity model has been developed by considering geometrical parameters of the substrate such as the porosity of the membrane and the height of the nanowires and is discussed briefly. For the effective permeability we have developed two analytical models, volumetric and variational. We will show that the variational approach agrees better with experiment and is able to take lossy gyro-magnetic media, such as ferromagnetic nanowires, into account. The models have been validated by S-parameter measurements of microstrip lines on a substrate filled with cobalt nanowires.

Preparation of thick YBa2Cu3O7−δ films by dc magnetron sputtering

High-temperature superconducting films up to 3.6 μm thick were obtained and their properties requisite for the development of microwave devices were investigated. It is shown that YBa2Cu3O7−δ films of thickness exceeding 3–5λL may be obtained for use in the microwave range.

ActiveX control for a semiconductor plate in a waveguide

The scattering of electromagnetic waves by a thin semiconductor plate placed at the center of the transverse cross section of a rectangular waveguide is studied. The relation between the electrodynamic parameters (reflection, absorption, and transmission coefficients) and the characteristics of the semiconductor material (carrier density, carrier mobility, and scattering time) is determined. The idea of the visual library, physical ActiveX (p-ActiveX), for modeling of physical processes is set forth. A description of this library is presented for a wide range of workers engaged in the development of microwave devices with a semiconductor plate as the active element, and a computer file containing this library is provided. (The names ActiveX and Windows are registered trademarks of the Microsoft Corporation.)