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.
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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.
87 citations
Cites background from "Perturbation Technique to Improve P..."
...In fact, it is common knowledge that conductive metal bodies (vias here) can perturb, constrain, or counteract EM waves [24], [25]....
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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.
14 citations
Cites background or result from "Perturbation Technique to Improve P..."
...Also, this approach appears equally effective such as earlier perturbation technique [12] in terms of the XP performance and considerably improved compared to that in [11]....
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...For other commonly used feeds such as by microstrip line or aperture coupling, the metallic perturbations of [11] and [12] are found to fail....
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...It is important to note that both approaches explored in [11] and [12] work only in the probe-fed configuration of a CDRA....
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...probe-fed, horizontal metal pin perturbation [12]# 4....
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...2582516 technique of perturbation by metals [11], [12]....
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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.
11 citations
TL;DR: In this paper, the glueless technology of a dielectric resonator antenna (DRA) was extended to its most popularly used probe-fed geometry to achieve a comprehensive solution in terms of adhesive-free stable deployment along with improved radiation characteristics.
Abstract: This article extends the glueless technology of a dielectric resonator antenna (DRA) to its most popularly used probe-fed geometry to achieve a comprehensive solution in terms of adhesive-free stable deployment along with improved radiation characteristics. Obtaining reduced cross-polarized (XP) fields through the glueless technique for commercial use is demonstrated in this article for the first time. It incorporates a single unit-shaped ground plane along with a pair of horizontal pins inserted through the DRA body and clamped with the metallic units of the structure. The study is based on the HEM11d mode, and the design maintains unperturbed modal characteristics. This has been experimentally verified for a 4-GHz antenna indicating as much as a 6-dBi gain with about a 12-dB reduction in cross-polar fields. This should find potential uses in practical applications.
7 citations
Cites background from "Perturbation Technique to Improve P..."
...[10], who aimed to enhance the strength of the primary mode and hence to weaken the XP-generating higher mode....
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01 Jul 2019
TL;DR: In this article, a 2×2 CDRA array with high gain and reduced cross-polarization has been proposed, which employs an on-board 180° phase inverter as a balun for differential feeding.
Abstract: This paper presents a compact novel 2×2 CDRA array with high gain and reduced cross polarization. By feeding the array elements differentially, the reduction of cross polarization and the enhancement of gain are achieved. The feeding network employs an on-board 180° phase inverter as a balun for differential feeding of array elements. The simulated results show that the proposed array achieves −10 dB impedance bandwidth of 5.78−5.9 GHz with a broadside radiation pattern having a peak realized gain of 11.07 dBi at 5.84 GHz. The cross-polarization levels in the boresight direction are −30.65 dB and −29.5 dB in YZ and XZ plane, respectively at 5.84 GHz. The proposed CDRA array is compact, making it suitable for portable devices.
6 citations
Cites background from "Perturbation Technique to Improve P..."
...Metal pins are inserted inside the CDRA to strengthen the electric fields of fundamental HEM11δ mode and weaken the fields of higher order modes, thereby suppressing the cross polarization [4]....
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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.
1,434 citations
"Perturbation Technique to Improve P..." refers background in this paper
...with the cylindrical geometry [1]–[3], which is probably the most celebrated one in the DRA community....
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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 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.
106 citations
"Perturbation Technique to Improve P..." refers background in this paper
...several improvements and features, such as circular polarization [5]– [7], miniaturization [8], [9], enhancement of bandwidth [10], [11], controlling antenna parameters [12], frequency tuning [13], [14], dual band operations [15], and recently, enhancement of gain [16]....
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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.
77 citations
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.
50 citations