J. James

Bio: J. James is an academic researcher from South Carolina State University. The author has contributed to research in topics: Resonator & Dielectric. The author has an hindex of 4, co-authored 4 publications receiving 416 citations.

Computed Modal Field Distributions for Isolated Dielectric Resonators

Abstract: Electric- and magnetic-field patterns for five of the lowest resonant modes in cylindrical dielectic resonators are displayed in various planes of intersection. The computational procedure is based on a method moments solution of the surface integral equation for bodies of revolution. Improvement of the numerical stability through the normalization of the matrix is discussed, and an algorithm for the evaluation of the modal field components is described.

Evaluation of Modes in Dielectric Resonators Using a Surface Integral Equation Formulation

Abstract: A moment method solution procedure for rotationally symmetric dielectric bodies has been applied to isolated cylindrical dielectric resonators, and the frequencies, as well as Q factors due to radiation, have been determined for several of the lowest modes, including those of hybrid type.

Computed Modal Field Distributions of Isolated Dielectric Resonators

Abstract: Equivalent surface currents obtained from the solution of a surface integral equation model for a dielectric resonator are utilized to evaluate the electric and magnetic fields inside and outside of the isolated dielectric resonator. The resulting field plots permit a positive mode identification, and they are useful in designing devices to enhance coupling of or to suppress various modes.

Evaluation of Modes in Dielectric Resonators Using a Surface Integral Equation Formulation

Abstract: A moment method solution procedure for rotationally symmetric dielectric bodies has been applied to isolated cylindrical dielectric resonators, and the frequencies as well as Q factors due to radiation have been determined for several of the lowest modes including those of hybrid type including those of hybrid type.

Dielectric resonator antennas—a review and general design relations for resonant frequency and bandwidth

Abstract: Open dielectric resonators (DRs) offer attractive features as antenna elements. These include their small size, mechanical simplicity, high radiation efficiency due to no inherent conductor loss, relatively large bandwidth, simple coupling schemes to nearly all commonly used transmission lines, and the advantage of obtaining different radiation characteristics using different modes of the resonator. In this article, we give a comprehensive review of the modes and the radiation characteristics of DRs of different shapes, such as cylindrical, cylindrical ring, spherical, and rectangular. Further, accurate closed form expressions are derived for the resonant frequencies, radiation Q-factors, and the inside fields of a cylindrical DR. These design expressions are valid over a wide range of DR parameters. Finally, the techniques used to feed DR antennas are discussed. © 1994 John Wiley & Sons, Inc.

Dielectric resonators

Abstract: Microwave passive and active devices containing dielectric resonators and the design procedures used to characterize these components are reviewed. The emphasis has been on low noise, small size, low cost and high temperature stability. Both filter and oscillator applications are described. The applications of dielectric resonators in the millimeter-wave frequency band are also discussed. >

Recent advances in dielectric-resonator antenna technology

Abstract: This paper features some of the advances in dielectric-resonator antenna technology at the Communications Research Centre. Several novel elements are presented that offer significant enhancements to parameters such as impedance bandwidth, circular-polarization bandwidth, gain, or coupling to various feed structures. Several linear and planar arrays are also presented, to illustrate the performance of dielectric-resonator antenna elements in the array environment.

Computed Modal Field Distributions for Isolated Dielectric Resonators

Abstract: Electric- and magnetic-field patterns for five of the lowest resonant modes in cylindrical dielectic resonators are displayed in various planes of intersection. The computational procedure is based on a method moments solution of the surface integral equation for bodies of revolution. Improvement of the numerical stability through the normalization of the matrix is discussed, and an algorithm for the evaluation of the modal field components is described.

Broadband stacked dielectric resonator antennas

Abstract: The input impedance of stacked cylindrical dielectric resonator antennas is investigated experimentally. The dielectric resonators are made of different materials. The bandwidth of 25% has been observed for a standing wave ratio better than 2.