Perturbation Technique to Improve Purity of Modal Fields in Dielectric Resonator Antenna Resulting in Reduced Cross-Polarized Radiation
TL;DR: In this article, a coax-fed cylindrical DRA with a pair of horizontally oriented metal pins protruded symmetrically face to face through it was examined with a view to improving the purity of modal fields leading to considerable reduction in unwanted cross-polarized (XP) radiations.
Abstract: Metallic perturbation in a body of a dielectric resonator antenna (DRA) has been explored with a view to improve the purity of modal fields leading to considerable reduction in unwanted cross-polarized (XP) radiations. A coax-fed cylindrical DRA (CDRA) has been examined with a pair of horizontally oriented metal pins protruded symmetrically face to face through it. The concept behind the design has been discussed and established using simulated results followed by a series of experimental verifications. As much as 10 dB reduction in principal plane XP values without affecting the primary radiation has been demonstrated. Purity in the modal fields is accounted for in terms of achieved isolation between co- and cross-polarized radiations, which attains 25–40 dB over 100° beamwidth.
Citations
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TL;DR: In this article, a simple decoupling method of using metallic vias to improve the isolation of millimeter-wave multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) elements is investigated.
Abstract: A simple decoupling method of using metallic vias to improve the isolation of millimeter-wave multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) elements is investigated. The vias are vertically added to the DRA elements, at appropriate positions. By means of the interaction with the electromagnetic fields, the vias can potentially affect the filed distributions and further reduce the coupled fields effectively. The isolation between the MIMO DRA elements can, therefore, be enhanced substantially. As the vias are placed inside the DRA elements, no extra footprint is needed, making the entire antenna system very simple and compact. Two typical examples, including an H-plane and an E-plane, coupled $1\times2$ MIMO DRA arrays, have been designed, fabricated, and measured to demonstrate the feasibility and universality of this method. The results show that by using the vias appropriately, the isolation of the H-plane coupled MIMO DRA array can be enhanced from ~15.2 to 34.2 dB, while that of the E-plane array can be improved from ~13.1 to 43 dB at 26 GHz.
28 citations
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TL;DR: In this paper, a technique of dielectric perturbation in a DRA has been explored with specific application to filter out higher resonating modes causing unwanted radiations, which is especially conceived and conjectured for microstripfed cylindrical DRA (CDRA).
Abstract: A technique of dielectric perturbation in a dielectric resonator antenna (DRA) has been explored with specific application to filter out higher resonating modes causing unwanted radiations. This is especially conceived and conjectured for microstripfed cylindrical DRA (CDRA). Creating a protruded cavity in it filled with dielectric material of varying er is the primary mechanism. Effect of such perturbation has been experimentally demonstrated establishing air (e
r
= 1) as the simplest and most promising one for a specific application in weakening HEM
21δ
mode in it, recently identified as the source of cross-polar radiations. Physical insight into this new technique is also clarified. As much as 10 dB reduction in the principal plane cross-polarized values without affecting the primary radiations has been documented.
13 citations
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TL;DR: In this article, a simple and miniaturized design of rectangular microstrip patch antenna (RMPA) is presented with improved cross-polarization (XP) purity, which is much more flexible to tune the resonance frequency of the antenna for its optimum performance.
Abstract: A simple and miniaturized design of rectangular microstrip patch antenna (RMPA) is presented with improved cross-polarization (XP) purity. This design approach is much more flexible to tune the resonance frequency of the antenna for its optimum performance. A complete design guideline based on theoretical analysis has been provided to estimate the antenna resonance frequency and corresponding resonant mode. The higher-order spurious mode, orthogonal to the co-polarized fields, has been identified as the source of XP radiation. The physical insight into the XP suppression has been thoroughly discussed and successfully applied for an optimum design. An improved antenna configuration has been realized without any perturbation in the radiating patch or the ground plane. Size, gain, and impedance matching of the proposed antenna have also been considered along with the suppression of XP value. This may be applicable to any conventional working RMPA by introducing very small possible changes. As much as 16 dB suppression of XP radiation is realized in the H-plane without affecting the co-polarized peak-gain value of 5.27 dBi. The proposed concept has been experimentally validated using a set of antenna prototypes. Measured results are closely corroborated with the simulated predictions.
8 citations
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TL;DR: In this article, a cylindrical dielectric resonator antenna (DRA) was excited with a microstrip line in the HEM 11δ姫 mode, and it was demonstrated that at the operating frequency, minimum cross-polarisation occurs when the lateral dimension of the substrate is slightly higher than half a free-space wavelength.
Abstract: A cylindrical dielectric resonator antenna (DRA) has been excited with a microstrip line in the HEM
11δ
mode. It is demonstrated that at the operating frequency, minimum cross-polarisation occurs when the lateral dimension of the substrate is slightly higher than half a free-space wavelength (
λ
0
). This occurs when direct waves from the DRA interfere appropriately with the waves that are diffracted from the substrate edges. For a 50Ω microstrip-fed cylindrical DRA, numerical prediction suggests a substrate of lateral dimension 0.58
λ
0
for the lowest possible cross-polarisation. In addition, the above optimum substrate size is constant irrespective of the substrate shape (square or circle) or dielectric resonator (DR) properties (permittivity and aspect ratio) for a given substrate permittivity. Numerical results are experimentally verified for a DRA with permittivity 24 and aspect ratio 1.33, for both square and circular substrates at the respective operating frequencies.
3 citations
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TL;DR: A three-dimensional dual-band dielectric resonator antenna, comprised of five rectangular RDR radiating elements, is proposed for wireless communication applications, which exhibits a gain of 7 dB in the lower band while 7.2 dB gain is obtained in the upper band.
Abstract: A three-dimensional dual-band dielectric resonator antenna, comprised of five rectangular dielectric resonator (RDR) radiating elements, is proposed for wireless communication applications. The presented multiple-input-multiple-output (MIMO)/diversity antenna system use TE
1δ1
Y
and HEM
2δ1
modes of the RDR antenna for the transmission/reception of data. The TE
1δ1
Y
mode covers the frequency range from 3.3 to 3.8 GHz, covering Wi-MAX, sub-6 GHz, and LTE (3.41-3.5 GHz uplink/3.51-3.6 GHz downlink) 5G application bands. The HEM
2δ1
mode covers Wi-Fi (5.725-5.875 GHz) and ITS 5.9 GHz (5.875-5.925 GHz) bands. The five RDR antenna elements are excited through coaxial feeds and are arranged in a cubical fashion to cover all directions, except -Z direction. The RDR elements are oriented and positioned to achieve a minimum correlation between the radiating elements. The proposed antenna exhibits a gain of 7 dB in the lower band while 7.2 dB gain is obtained in the upper band.
3 citations
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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.
1,286 citations
"Perturbation Technique to Improve P..." refers background in this paper
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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
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TL;DR: In this article, a single parasitic patch for circular polarization excitation of the dielectric resonator antenna (DRA) is investigated, and the integral equations for the conformal-strip and parasitic-patch currents are formulated by matching the appropriate boundary conditions.
Abstract: The use of a single parasitic patch for circular polarization (CP) excitation of the dielectric resonator antenna (DRA) is investigated. For demonstration, the technique is applied to the conformal-strip fed hemispherical DRA, excited at the fundamental TE/sub 111/ mode. Using the Green's function approach, the integral equations for the conformal-strip and parasitic-patch currents are formulated by matching the appropriate boundary conditions. The equations are then solved using the method of moments (MoM). In using the MoM, both the rigorous and simplified current expansions are used for the parasitic patch, and their results are compared with each other. In each case, the impedance integrals are evaluated by virtue of newly obtained recurrence formulas and direct analytical integration. Hence, the results can be calculated very efficiently without the need for any numerical integration, which greatly facilitates the numerical implementation. The input impedance, axial ratio, and radiation patterns of the CP DRA are calculated, and the results are in good agreement with measurements.
95 citations
"Perturbation Technique to Improve P..." refers background in this paper
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TL;DR: In this article, a linear array of rectangular dielectric resonator antennas (DRAs) fed by DIGs was designed to achieve a specific power distribution, the power coupled to each DRA is controlled by changing the spacing between the DRAs and the DIG.
Abstract: Design of a linear array of rectangular dielectric resonator antennas (DRAs) fed by dielectric image guide (DIG) is presented. Coupling between the DIG and the DRAs is predicted using the effective dielectric constant method. In order to achieve a specific power distribution, the power coupled to each DRA is controlled by changing the spacing between the DRAs and the DIG. Cross polarization reduction is achieved by wrapping a conducting strip around the middle of the DRA without affecting the co-polarized radiation pattern. The antenna is fabricated and tested. Good agreement between the measured and computed results is obtained.
69 citations
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TL;DR: In this article, a rigorous analysis of the conformal-strip-excited hemispherical dielectric resonator antenna (DRA) with multiple parasitic strips is presented, where the problem is formulated using the Green's function approach, with the strip currents solved by using the method of moments.
Abstract: A rigorous analysis of the conformal-strip-excited hemispherical dielectric resonator antenna (DRA) with multiple parasitic strips is presented in this paper. The problem is formulated using the Green's function approach, with the strip currents solved by using the method of moments. It is found that the strips can be used to tune the operating frequency of both the linearly polarized (LP) and circularly polarized (CP) DRAs. In designing the LP DRA, the parasitic strips are placed symmetrically in pairs to minimize cross-polarized radiation fields. For the CP DRA, however, the parasitic strips are asymmetric, with their parameters determined by using the Genetic Algorithm. Measurements were carried out to verify the calculations, and reasonable agreement between theory and experiment is obtained.
48 citations
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