# Dielectric Resonator Antennas

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

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01 Jan 2015

TL;DR: In this article, the authors focused on circularly polarized antennas and provided key definitions and governing equations of circular polarization, and extended the concept to the magnetic source counterparts and Huygens sources.

Abstract: This chapter is focused on circularly polarized antennas. Key definitions and governing equations of circular polarization are given. Infinitesimal dipole sources are considered to establish circularly polarized radiation. First, radiation patterns of cross dipoles are mathematically reviewed, from which the condition of circularly polarized waves is concluded. Later, the idea is extended to four displaced sequentially rotated dipole antennas, resulting in circularly polarized waves within a wide angular range in space. The extension of the concept to the magnetic source counterparts and Huygens sources is briefly discussed. Other than point sources, also known as one-dimensional current sources, sources of circularly polarized radiation are further investigated for two-dimensional cases, such as microstrip patch antennas, and threedimensional structures, such as volumetric current sources existing in dielectric resonator antennas. For these cases, the creation of circularly polarized radiation using single-feed and dual-feed, perturbed structures and sequentially rotated method is described. As a design example, numerical andmeasurement results of circularly polarized square patch ring antennas are extensively discussed and presented in this chapter. The square-ring microstrip antenna is selected as it closely approximates the sequentially rotated currents, and also it has not been widely studied in the literature.

327 citations

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TL;DR: In this paper, a low-loss and low-cost solution for high gain terahertz (THz) antennas is proposed, where variable height dielectric elements are used in the reflectarray designs.

Abstract: Dielectric reflectarray antennas are proposed as a promising low-loss and low-cost solution for high gain terahertz (THz) antennas. Variable height dielectric elements are used in the reflectarray designs, which allow for the use of low dielectric-constant materials. Polymer-jetting 3-D printing technology is utilized to fabricate the antenna, which makes it possible to achieve rapid prototyping at a low-cost. Numerical and experimental results are presented for 3 different prototypes operating at 100 GHz, which show a good performance. Moreover the methodology proposed here is readily scalable, and with the current material and fabrication technology, designs up to 1.0 THz can be realized. This study reveals that the proposed design approach is well suited for low-cost high-gain THz antennas.

255 citations

### Cites background from "Dielectric Resonator Antennas"

...In the first approach, the phasing elements of the reflectarray are dielectric resonators [18], [19], and phase tuning is typically achieved by changing the length of the dielectric cavity....

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03 Apr 2012TL;DR: The basic characteristics of dielectric resonator antennas are explained, with emphasis on the effect of the form factor on their resonance (operating) frequencies.

Abstract: This paper explains the basic characteristics of dielectric resonator antennas (DRAs), with emphasis on the effect of the form factor on their resonance (operating) frequencies. It is followed by discussions on their recent developments in higher order mode, circularly polarized, dual function, and transparent designs over the last few years. The idea of using glass DRAs as decoration antennas is proposed and demonstrated for the first time.

237 citations

### Cites background from "Dielectric Resonator Antennas"

...Thus far, there have been two research books [8], [9] on DRAs and several excellent review papers [10]–[13]....

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...DRAs can be excited with different feeding schemes [8], such as coaxial probe, coupling slot, microstrip line, coplanar waveguide, conformal strip, dielectric image guide, or metallic waveguide....

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19 Jul 2007TL;DR: In this article, the antenna comprises a substrate, a feed conductor, a ground layer, a resonator and a short-circuited element, which is disposed on the first side connecting the ground layer.

Abstract: An antenna comprises a substrate, a feed conductor, a ground layer, a resonator and a short-circuited element. The substrate comprises a first surface and a second surface. The feed conductor is formed on the first surface. The ground layer is formed on the second surface, comprising an aperture. The resonator is disposed on the ground layer, comprising a body and a notch, the notch is formed on a first side of the body, wherein the first side is perpendicular to the ground layer. The short-circuited element is disposed on the first side connecting the ground layer.

189 citations

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TL;DR: In this article, a circularly polarized rectangular stair-shaped dielectric resonator antenna (DRA) is presented, which is excited by a narrow rectangular slot and rotated 45/spl deg/ with respect to the sides of the DRA to generate circular polarization.

Abstract: A circularly polarized rectangular stair shaped dielectric resonator antenna (DRA) is presented. The DRA is excited by a narrow rectangular slot and rotated 45/spl deg/ with respect to the sides of the DRA to generate circular polarization. A parametric study of the length to width ratio to optimize the axial ratio bandwidth is given. A 3 dB axial ratio bandwidth of 10.6% is achieved when the length to width ratio is 1.9.

161 citations

##### References

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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

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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

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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

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Kyocera

^{1}TL;DR: In this paper, a waveguide of new structure has been developed for millimeter-wave applications, which can be embedded in a substrate and is able to be wired in three dimensions, and its transmission characteristics are evaluated using a glass-ceramic substrate of dielectric constant, /spl epsiv/sub r/=5, and loss, tan /spl delta/=0.0008.

Abstract: A waveguide of new structure has been developed for millimeter-wave applications. The dielectric waveguide is constructed with sidewalls consisting of lined via-holes and edges of metallized planes. This structure can be manufactured by lamination techniques, so we refer to the waveguide as a "laminated waveguide". The laminated waveguide can be embedded in a substrate and is able to be wired in three dimensions. The transmission characteristics are evaluated using a glass-ceramic substrate of dielectric constant, /spl epsiv//sub r/=5, and loss, tan /spl delta/=0.0008. Insertion loss per unit length of the guide is estimated to be less than 0.5 dB/cm at 83 GHz. Furthermore, it was confirmed that the laminated waveguide is suitable to feeding lines for a small sized plane array antenna. By electromagnetic simulation, it has been confirmed that fundamental structures, such as bends, branches, power dividers, and interconnections between upper and lower layers can be realized with sufficient performances.

493 citations