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Journal ArticleDOI

A state‐of‐art review on performance improvement of dielectric resonator antennas

About: This article is published in International Journal of Rf and Microwave Computer-aided Engineering.The article was published on 2018-08-01. It has received 39 citations till now. The article focuses on the topics: Dielectric resonator antenna & Dielectric resonator.
Citations
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Journal ArticleDOI
TL;DR: In this article, an overview of dielectric materials employed as spacers, and fabrication methods employed to realize these devices at the terahertz frequency range are also presented; material selection guidelines, material-specific and application-specific fabrication quality metrics are outlined, and new techniques are proposed.
Abstract: Manipulation of terahertz radiation opens new opportunities that underpin application areas in communication, security, material sensing, and characterization. Metasurfaces employed for terahertz manipulation of phase, amplitude, or polarization of terahertz waves have limitations in radiation efficiency which is attributed to losses in the materials constituting the devices. Metallic resonators‐based terahertz devices suffer from high ohmic losses, while dielectric substrates and spacers with high relative permittivity and loss tangent also reduce bandwidth and efficiency. To overcome these issues, a proper choice of low loss and low relative permittivity dielectric layers and substrates can improve field confinement and reduce dissipation. Alternatively, replacing metallic resonators with a moderate relative permittivity dielectric material that supports cavity mode resonances also reduces dissipation due to the absence of conduction current. Herein, an overview of dielectric materials employed as spacers and dielectric resonators is provided, and the fabrication methods employed to realize these devices at the terahertz frequency range are also presented. Material selection guidelines, material‐specific and application‐specific fabrication quality metrics are outlined, and new techniques are proposed.

69 citations

Journal ArticleDOI
TL;DR: A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented.
Abstract: A review paper concerning wide-band and ultra-wideband (UWB) antennas used for wireless communication purposes in terms of the materials as well as a numerical analysis is presented. These antennas which are taken into account are listed as wide-band microstrip antenna, wide-band monopole antenna over a plate, wide-slot UWB antenna, stacked patch UWB antenna, taper slot (TSA) UWB antenna, metamaterial (MTM) structure UWB antennas, elliptical printed monopole UWB antenna, and flexible wearable UWB antenna. The antennas’ performance is compared based on their size and how they can be applicable for portable communication device applications. This review paper furnishes a proper direction to select varieties of figures in terms of impedance bandwidth, gain, directivity, dimensions, time domain characteristics, and materials affecting these antenna’s characteristics.

63 citations

Journal ArticleDOI
TL;DR: This article attempts to critically review the wearable antennas especially in light of new materials and fabrication methods, and novel designs, such asminiaturized button antennas and miniaturized single and multi-band antennas, and their unique smart applications in WBAN.
Abstract: The demand for wearable technologies has grown tremendously in recent years. Wearable antennas are used for various applications, in many cases within the context of wireless body area networks (WBAN). In WBAN, the presence of the human body poses a significant challenge to the wearable antennas. Specifically, such requirements are required to be considered on a priority basis in the wearable antennas, such as structural deformation, precision, and accuracy in fabrication methods and their size. Various researchers are active in this field and, accordingly, some significant progress has been achieved recently. This article attempts to critically review the wearable antennas especially in light of new materials and fabrication methods, and novel designs, such as miniaturized button antennas and miniaturized single and multi-band antennas, and their unique smart applications in WBAN. Finally, the conclusion has been drawn with respect to some future directions.

50 citations

Journal ArticleDOI

20 citations


Cites background from "A state‐of‐art review on performanc..."

  • ...It possesses numerous advantages such as high efficiency, low metallic loss, minimum surface waves, wideband characteristics, and degree of design freedom.(1-7) DRA consists of a dielectric resonator (DR) that is made of a non-conducting material, a ground plane, and a dielectric substrate resides in between the DR and the ground plane....

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  • ...As the resonance frequency is proportional to 1ffiffiffiεrp , therefore, Equation (7) indicates that the Q-factor is decreased when volume to surface area of DR is reduced and also there is enhancement of bandwidth....

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  • ...By applying the CP conditions, the resultant equation will be: E z, tð Þ=Eocos ωt−βzð Þx̂+Eoejπ2cos ωt−βzð Þŷ ð3Þ At a fixed position that is, z = 0 (direction of propagation), the Equation (3) can be written as: E 0, tð Þ=Eocos ωtð Þx̂+Eocos ωt+ π2 ŷ ð4Þ By applying the different phases that is, ωt = 0 , 90 , 180 , and 270 in Equation (4), the corresponding graphical representation of x and y component of electric fields are shown in Figure 3....

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  • ...The dimensions of RDRA are calculated by using the following curve fitting equations.88 f GHz = 15F πwdra cmð Þ ffiffiffiffiffiffiffiffiffi εr,dra p ð5Þ where, F denotes as normalized frequency of the RDRA that is determined by the following Equation (6): F =X0 +X1 Wdra 2Hdra 1 +X2 Wdra 2Hdra 2 ð6Þ where, X0 = 2:57-0:8 Ldra 2Hdra 1 + 0:42 Ldra 2Hdra 2 −0:05 Ldra 2Hdra 3 X1 = 2:71 Ldra 2Hdra −0:282 X2 = 0:16 where f GHz is the resonant frequency at 2.4 GHz. ϵr,dra is permittivity of DR and Wdra, Ldra and Hdra are the width, length and height of the DR in cm respectively....

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  • ...In addition, the bandwidth of antenna-3 is also increased due to decrease in volume to surface area of DR as shown in following Equation (7)....

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Journal ArticleDOI

17 citations


Cites background from "A state‐of‐art review on performanc..."

  • ...Dielectric resonator antennas (DRAs) have received increasing attention due to its striking characteristics of low loss, low cost, and high design flexibility.(2-4) In recent years, several advanced techniques are developed to solve the DRA's fabrication and positioning issue in an array,(5,6) making it more competitive in future wireless communication systems....

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References
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Journal ArticleDOI
01 Jul 1984

5,335 citations


"A state‐of‐art review on performanc..." refers background in this paper

  • ...For case of single point feed, the shape of the resonator plays the crucial role to generate spatially orthogonal modes, while in multipoint feed, this can be generated by the feeding network and independent of the shape of the dielectric resonator.(60,61) In case of DRA, the research on only circular polarization62–158 and circular polarization with other charateristics159–166 are quite remarkable....

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  • ...Circular polarization (Figure 5) is the special case of elliptical polarization.(60) It is obvious that circular polarization in a DRA can be ensured by exciting two quasi-degenerate modes in the resonator which are typically in phase quadrature and spatially orthogonal to each other....

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Journal ArticleDOI
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


"A state‐of‐art review on performanc..." refers background in this paper

  • ...For medium gain requirement, standard DRA works well, but sometimes it becomes application restraint because of medium gain charateristics.(2) So different techniques have been proposed to enhance the gain as per the requirement....

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Book ChapterDOI
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


"A state‐of‐art review on performanc..." refers background in this paper

  • ...As for hemispherical dielectric resonator (DR) the radius of the hemisphere, for cylindrical, the ratio of radius to height, and for rectangular, the ratio of length to width and depth to width controls the resonant frequeny.(3,4) Moreover, this antenna supports wide range of coupling techniques enabling several radiation modes....

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Journal ArticleDOI
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

Journal ArticleDOI
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