Dualband Cylindrical Dielectric Resonator Antenna Employing ${\rm HEM}_{{11\delta}}$ and ${\rm HEM}_{{12\delta}}$ Modes Excited by New Composite Aperture
TL;DR: In this article, a composite aperture has been conceived to excite cylindrical dielectric resonator antenna (CDRA) simultaneously with two different modes, resulting in broadside radiations at two adjacent bands.
Abstract: A composite aperture has been conceived to excite cylindrical dielectric resonator antenna (CDRA) simultaneously with two different modes, resulting in broadside radiations at two adjacent bands. Threefold objectives of this investigation includes: (i) to realize ${\rm HEM}_{{12\delta}}$ mode in a practical CDRA without involving any unwanted hybrid mode; (ii) to explore composite aperture type feed, which serves as equivalent magnetic and electric dipoles to launch ${\rm HEM}_{{11\delta}}$ mode and ${\rm HEM}_{{12\delta}}$ mode, respectively; and hence (iii) to achieve a dual-mode dualband CDRA without compromising in any enlargement of antenna dimension. ${\rm HEM}_{{12\delta}}$ mode is a recent introduction by the present authors as a broadside radiating mode in a CDRA, although this investigation demonstrates a practically feasible application for the first time. Systematic study of newly proposed composite aperture is followed by experimental investigation with a set of prototypes operating at S and C bands. As much as 6 dBi gain with 7–8% matching bandwidth for each operating band has been experimentally demonstrated.
Citations
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TL;DR: In this paper, a spoof plasmon (SP)-based slow-wave feeding configuration is proposed, experimentally verified and exploited to excite the fundamental horizontally polarized mode of dielectric resonator antennas (DRAs).
Abstract: A spoof plasmon (SP)-based slow-wave feeding configuration is proposed, experimentally verified and exploited to excite the fundamental horizontally polarized mode of dielectric resonator antennas (DRAs). As an example, a cylindrical DRA operating at 3 GHz is fed by the proposed feeding structure. The simulation and measurement evidence the unique features of ${\rm TE}_{01\updelta}$ mode such as lower thickness-dependency of the resonant frequencies, superb miniaturization and ultra-compactness, and omnidirectional radiation for horizontally polarized waves. We anticipate that the ground-free SP-based feeding technique could be applied to effectively excite the more “unusual” modes of the isolated DRAs.
78 citations
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TL;DR: In this article, a low profile stacked dielectric resonator antenna (DRA) and a microstrip metasurface (MS) antenna are investigated and compared in this communication.
Abstract: A low profile stacked dielectric resonator antenna (DRA) and a microstrip metasurface (MS) antenna are investigated and compared in this communication. It has been found that very similar radiation performance including resonant modes, reflection coefficients, boresight gains, and radiation patterns can be obtained between them, indicating that the dielectric superstrate of stacked DRA plays analogous role with MS in enhancing the antenna bandwidth and realized gain. Based on this observation, a broadband, low profile, and high gain filtering cylindrical stacked DRA is inspired by an MS-based filtering antenna. Four resonant modes including the higher order HEM $_{31\delta }$ mode and HEM $_{13\delta }$ mode are simultaneously excited in the DRA to provide a broad bandwidth of 61.4% and a peak gain of 11.4 dBi within passband, whereas a shorting via and two pairs of transverse stubs are introduced into the feeding microstrip line to generate radiation nulls in stopband and realize filtering function. Second harmonic suppression has been achieved without increasing the footprint of the antenna, and an out-of-band suppression of more than 23 dB is obtained within the wide stopband.
52 citations
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TL;DR: In this paper, a new and physically realizable feed employing a dielectric resonator (DR) has been conceived and demonstrated for the 12-Delta mode in a cylindrical DRA, which enables in realizing an improved version of dual-band dual-mode DRA with attractive broadside radiation along with wide bandwidth characteristics.
Abstract: A new and physically realizable feed employing a dielectric resonator (DR) has been conceived and demonstrated for ${\rm HEM}_{12\delta}$ mode in a cylindrical dielectric resonator antenna (CDRA). This indeed enables in realizing an improved version of dual-band dual-mode dielectric resonator antenna (DRA) with attractive broadside radiation along with wide bandwidth characteristics. It comprises of a two-element stacked geometry, where the lower element is excited by an aperture and the upper element is excited by the lower DR. The upper element is responsible for generating the higher mode $({\rm HEM}_{12\delta})$ , whereas the lower mode $({\rm HEM}_{11\delta})$ resonates in the entire composite mass. The conjecture has been verified with an S/C-band design using simulated and measured results indicating three different variants. The most improved geometry comprising of a “cone on top of a cylinder” promises 6.5 and 10.3 dBi gains in the lower and upper operating bands with, respectively, 8.3% and 13% matching bandwidth. This newly addressed technique can be of potential use for newer innovations in DRA feed and design.
30 citations
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TL;DR: In this article, a cylindrical dielectric resonator antenna with switchable beams is proposed, which exhibits high gain (7.27 dBi), high efficiency (86.1%), low cross-polarization level, and similar radiation patterns.
Abstract: A cylindrical dielectric resonator antenna with switchable beams is proposed in this letter. The high-order HEM
21(1 + δ)
mode of cylindrical dielectric resonator is excited at 5.8 GHz for high gain and quasi-endfire radiation pattern for the first time. Eight switches, whose locations are carefully optimized, are used to control the beam directions. By turning on one of the eight PIN diodes, the proposed antenna can rotate the beam to the opposite direction of the switch. For each direction, the antenna exhibits high gain (7.27 dBi), high efficiency (86.1%), low cross-polarization level, and similar radiation patterns. With these advantages, the antenna can be widely applied in wireless communication systems, especially for multiple-input-multiple-output (MIMO) systems.
29 citations
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TL;DR: In this article, a compact quasi-isotropic dielectric resonator antenna (DRA) with filtering response is investigated in a communication. But the authors only evaluated the performance of the DRA at 2.4 GHz.
Abstract: A compact quasi-isotropic dielectric resonator (DR) antenna (DRA) with filtering response is first investigated in this communication. The cylindrical DRA is fed by a microstrip-coupled slot, exciting in its ${\text {HEM}}_{11 \delta }$ mode which radiates like a magnetic dipole. A small ground plane is used for this DRA and it radiates like an electric dipole. The combination of the two orthogonal dipoles leads to a quasi-isotropic radiation pattern, with gain deviation as low as 5.8 dB in the 360° full space. To integrate the filtering function, the microstrip feed-line and the ground plane are turned upside down, and further two stubs with different lengths are used together to excite the DR. Due to the different loading effects of the feeding stubs, two resonances of the DR ${\text {HEM}}_{11 \delta }$ mode are excited in the passband, effectively enhancing the bandwidth of DRA ( $\varepsilon _{r} = 20$ ) to 7%. Furthermore, two controllable radiation nulls are generated by the DR loaded microstrip feed-line, bringing about high frequency selectivity at the edges of the passband and a quasi-elliptic bandpass response. For demonstration, a prototype operating at 2.4 GHz was fabricated and tested; reasonable agreement is obtained between the simulated and measured results.
27 citations
References
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TL;DR: A mechanism for depression of the plasma frequency into the far infrared or even GHz band is proposed: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance.
Abstract: The plasmon is a well established collective excitation of metals in the visible and near UV, but at much lower frequencies dissipation destroys all trace of the plasmon and typical Drude behavior sets in. We propose a mechanism for depression of the plasma frequency into the far infrared or even GHz band: Periodic structures built of very thin wires dilute the average concentration of electrons and considerably enhance the effective electron mass through self-inductance. Computations replicate the key features and confirm our analytic theory. The new structure has novel properties not observed before in the GHz band, including some possible impact on superconducting properties.
3,690 citations
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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.
1,286 citations
"Dualband Cylindrical Dielectric Res..." refers background in this paper
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TL;DR: It is demonstrated theoretically that electromagnetic waves can be "squeezed" and tunneled through very narrow channels filled with epsilon-near-zero (ENZ) materials and it is discussed that in some cases the isotropy of the ENZ material may not be an issue.
Abstract: In this Letter, we demonstrate theoretically that electromagnetic waves can be ``squeezed'' and tunneled through very narrow channels filled with $\ensuremath{\epsilon}$-near-zero (ENZ) materials. We show that the incoming planar wave front is replicated at the output interface, independently of the specific geometry of the channel. A closed analytical formula is derived for the scattering parameters of a particular class of geometries. It is discussed that in some cases the isotropy of the ENZ material may not be an issue. A metamaterial realization of an anisotropic ENZ material is suggested and numerically studied.
1,111 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.
734 citations
Additional excerpts
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TL;DR: In this article, electric and magnetic field patterns for five of the lowest resonant modes in cylindrical dielectic resonators are displayed in various planes of intersection, based on a method moments solution of the surface integral equation for bodies of revolution.
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.
225 citations