Resonant hemispherical dielectric antenna
TL;DR: In this article, an antenna consisting of a resonant dielectric hemisphere on top of a ground plane is investigated, with emphasis on the lowest-order mode that results in efficient radiation in the direction perpendicular to the ground plane.
Abstract: An antenna consisting of a resonant dielectric hemisphere on top of a ground plane is investigated. Calculations of the internal and external fields are made with emphasis on the lowest-order mode that results in efficient radiation in the direction perpendicular to the ground plane. Measured input impedance data are also presented for a practical radiator.
Citations
More filters
15 Apr 2005
TL;DR: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article, where a parasitic patch is used to excite a nearly degenerate mode.
Abstract: Linearly and circularly polarized conformal strip-fed dielectric resonator antennas (DRAs) are studied in this article. In the latter case, a parasitic patch is used to excite a nearly degenerate mode. The hemispherical DRA, excited in its fundamental broadside TE111 mode, is used for the demonstration. In the analysis, the mode-matching method is used to obtain the Green's functions, whereas the method of moments is used to solve for the unknown strip currents. In order to solve the singularity problem of the Green's functions, a recurrence technique is used to evaluate the impedance integrals. This greatly increases the numerical efficiency. Measurements were carried out to verify the calculations, with good results.
Keywords:
circularly polarized antenna;
dielectric antennas;
mode-matching methods;
moment methods;
parasitic antennas;
resonance
898 citations
TL;DR: In this paper, a comprehensive review of the modes and the radiation characteristics of open dielectric resonators (DRs) of different shapes, such as cylindrical, spherical, and rectangular, is presented.
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.
861 citations
TL;DR: In this paper, the resonant frequencies and radiation Q-factors of the lowest order "magnetic-dipole" modes are derived on the basis of a first-order theory.
Abstract: Theoretical and experimental investigations on rectangular dielectric resonator antennas having a value of /spl epsiv//sub r/, in the range of 10 to 100 are reported. The resonant frequencies and radiation Q-factors of the lowest order "magnetic-dipole" modes are derived on the basis of a first-order theory. The accuracy of the model in predicting the resonant frequency and radiation Q-factor is verified by comparison with results of a rigorous theory and experiments. Various feeds for the antennas such as probe, microstrip slot, and microstrip line are described. Measured radiation patterns are shown and the effect of feed and mode degeneracy on the cross-polarisation levels is discussed.
703 citations
Cites background from "Resonant hemispherical dielectric a..."
...DRA’s can be easily excited using a probe (e.g., [4]‐[ 6 ], [11], [13], [14], [20]), microstrip slot [12], [15], [16], and direct microstrip coupling [7], [40]....
[...]
...However, systematic experimental investigations on dielectric resonator antennas (DRA’s) were first carried out by Long et al. [4]‐[ 6 ]....
[...]
...Probe-Coupling: It is seen from (2e) that for the TE mode, the component is maximum at and . The TE mode of a rectangular DRA placed on a ground plane can, therefore, be excited by keeping the probe, as shown in Fig. 2. In most of the earlier investigations reported on probe-fed DRA’s of various shapes, the probe protrudes inside the DRA (e.g., [4]‐[ 6 ], [11], [13], [14])....
[...]
Book•
01 Jan 2007
Abstract: In recent years, the dielectric resonator antenna (DRA) has emerged as a new and viable alternative to conventional low-gain elements such as dipoles, monopoles, and microstrip patches. This practical resource presents complete, up-to-date details on DRAs in a single volume. The book provides you with clear guidance on the mode of operation and radiation behavior of DRAs, the main methods of excitation, and the major advances in DRA technology. This hands-on reference equips you with simple equations and graphs that help you rapidly design DRAs of spherical, cylindrical, and rectangular shapes, without having to resort to complex analytical or numerical calculations. You find guidelines for designing feeds required to excite the DRAs, such as probes, apertures, and microstrip lines. In addition, the book offers you various techniques for enhancing the bandwidth performance of DRAs for wideband applications. You learn how to design low profile DRAs and DRAs with circular polarization. Several approaches for designing linear and planar DRAs arrays are also considered. Moreover, this comprehensive book provides advice on the fabrication of DRAs and measurement methods used to characterize their performance. Numerous design examples are included to give you a sense of the versatility that DRAs afford.
616 citations
TL;DR: In this paper, the authors present a historical review of the research carried out on dielectric resonator antennas (DRAs) over the last three decades and highlight major research activities in each decade.
Abstract: This article presents a historical review of the research carried out on dielectric resonator antennas (DRAs) over the last three decades. Major research activities in each decade are highlighted. The current state of the art of dielectric-resonator-antenna technology is then reviewed. The achievable performance of dielectric resonator antennas designed for compactness, wide impedance bandwidth, low profiles, circular polarization, or high gain are illustrated. The latest developments in dielectric-resonator-antenna arrays and fabrication techniques are also examined.
494 citations
References
More filters
Book•
01 Jun 1961
TL;DR: In this paper, a revised version of the Revised edition of the book has been published, with a new introduction to the concept of plane wave functions and spherical wave functions, as well as a detailed discussion of the properties of these functions.
Abstract: Foreword to the Revised Edition. Preface. Fundamental Concepts. Introduction to Waves. Some Theorems and Concepts. Plane Wave Functions. Cylindrical Wave Functions. Spherical Wave Functions. Perturbational and Variational Techniques. Microwave Networks. Appendix A: Vector Analysis. Appendix B: Complex Permittivities. Appendix C: Fourier Series and Integrals. Appendix D: Bessel Functions. Appendix E: Legendre Functions. Bibliography. Index.
5,655 citations
TL;DR: In this article, an experimental investigation of the radiation and circuit properties of a resonant cylindrical dielectric cavity antenna has been undertaken, and a simple theory utilizing the magnetic wall boundary condition is shown to correlate well with measured results for radiation patterns and resonant frequencies.
Abstract: An experimental investigation of the radiation and circuit properties of a resonant cylindrical dielectric cavity antenna has been undertaken. The radiation patterns and input impedance have been measured for structures of various geometrical aspect ratios, dielectric constants, and sizes of coaxial feed probes. A simple theory utilizing the magnetic wall boundary condition is shown to correlate well with measured results for radiation patterns and resonant frequencies.
1,434 citations
TL;DR: In this article, an antenna which consists of a resonant rectangular parallelepiped dielectric on top of a ground plane is described, and the effects of feed probe length variations are discussed.
Abstract: An antenna which consists of a resonant rectangular parallelepiped dielectric on top of a ground plane is described. Calculated radiation patterns and measured impedances are presented, and the effects of feed probe length variations are discussed.
322 citations
08 May 1967
TL;DR: In this paper, a systematic study is made of electromagnetic resonances of a spherical, free, and isotropic sample supposed to be without dielectric loss, and the results for the first modes (frequency and Q factor for /spl epsi/ varying between 1 and 100) are presented.
Abstract: A systematic study is made of electromagnetic resonances of a spherical, free, and isotropic sample supposed to be without dielectric loss. The characteristic equation which is both complex and transcendant has been resolved with a computer. The results for the first modes (frequency and Q factor for /spl epsi/ varying between 1 and 100) are presented. The Q factor that is calculated represents the comparison between the energy stored by the resonance system and energy radiated per cycle; this is the theoretical maximum Q in the case of nonlossy materials. The different modes are classed in TE/sub nmr/ and TM/sub nmr/ modes which comprise exterior and interior modes. It is shown that for n >or= r the energy is concentrated in all directions near the surface; these are known as surface modes. This systematic study is confirmed by experiments in which numerous modes have been observed and identified.
219 citations
TL;DR: In this article, the driving point impedance of a printed-circuit antenna consisting of a circular disc separated by a dielectric from a ground plane is investigated experimentally and a theoretical parallel RLC circuit model is proposed and compared with the experimental data.
Abstract: The driving-point impedance of a printed-circuit antenna consisting of a circular disc separated by a dielectric from a ground plane is investigated experimentally. The impedance is measured as a function of the operating frequency for various disc diameters, thicknesses and permittivities of the dielectric and feed point positions. In addition, a theoretical parallel RLC circuit model is proposed and compared with the experimental data.
50 citations