Wideband omnidirectional dielectric resonator antenna
11355852 · 2022-06-07
Assignee
Inventors
Cpc classification
H01Q1/36
ELECTRICITY
International classification
H01Q1/36
ELECTRICITY
Abstract
A dielectric resonator antenna and a dielectric resonator antenna array. The dielectric resonator antenna includes a ground plane, a dielectric resonator element operably coupled with the ground plane, and a feed network operably coupled with the dielectric resonator element for exciting the dielectric resonator antenna to provide a wideband omnidirectional response. The dielectric resonator element includes a plurality of portions, including, at least, an innermost portion and an outermost portion arranged around the innermost portion. The innermost portion has a first effective dielectric constant and outermost portion has a second, different effective dielectric constant.
Claims
1. A dielectric resonator antenna, comprising: a ground plane; a dielectric resonator element operably coupled with the ground plane; and a feed network operably coupled with the dielectric resonator element for exciting the dielectric resonator antenna to provide a wideband omnidirectional response; wherein the dielectric resonator element comprises a plurality of portions, the plurality of portions comprises: an innermost portion having a first effective dielectric constant; and an outermost portion arranged around the innermost portion and having a second effective dielectric constant different from the first effective dielectric constant; wherein the feed network is arranged to excite a plurality of transverse magnetic modes of the dielectric resonator antenna, and the plurality of transverse magnetic modes comprises TM.sub.01δ mode, TM.sub.02δ mode, and TM.sub.03δ mode.
2. The dielectric resonator antenna of claim 1, wherein the innermost portion defines an axis and the outermost portion is arranged around the innermost portion about the axis.
3. The dielectric resonator antenna of claim 1, wherein the second effective dielectric constant is smaller than the first effective dielectric constant.
4. The dielectric resonator antenna of claim 1, wherein in plan view the innermost portion has a first outer contour and the outermost portion has a second outer contour; and wherein the first outer contour and the second outer contour are of a same type of shape and are of different sizes.
5. The dielectric resonator antenna of claim 1, wherein the innermost portion and the outermost portion have different air-filling ratios.
6. The dielectric resonator antenna of claim 1, wherein the innermost portion is generally prismatic.
7. The dielectric resonator antenna of claim 6, wherein the outermost portion is formed by a waffle structure with multiple grid cells.
8. The dielectric resonator antenna of claim 7, wherein the grid cells are defined by walls of the same thickness.
9. The dielectric resonator antenna of claim 1, wherein the innermost portion has a first height and the outermost portion has a second height larger than the first height.
10. The dielectric resonator antenna of claim 1, wherein the plurality of portions further comprises one or more intermediate portions arranged around the innermost portion and nested between each other and between the innermost portion and the outermost portion.
11. The dielectric resonator antenna of claim 10, wherein the respective effective dielectric constant of the one or more intermediate portions is smaller than the first effective dielectric constant and larger than the second effective dielectric constant.
12. The dielectric resonator antenna of claim 10, wherein the one or more intermediate portions include multiple nested intermediate portions each having a respective effective dielectric constant, and wherein the respective effective dielectric constants are different and are smaller than the first effective dielectric constant and larger than the second effective dielectric constant.
13. The dielectric resonator antenna of claim 12, wherein the respective effective dielectric constants decreases between each intermediate portion from the innermost portion to the outermost portion such that among all the intermediate portions the intermediate portion closest to the innermost portion has the largest effective dielectric constant and the intermediate portion closest to the outermost portion has the smallest effective dielectric constant.
14. The dielectric resonator antenna of claim 10, wherein the innermost portion, the one or more intermediate portions, and the outermost portion are generally concentric.
15. The dielectric resonator antenna of claim 14, wherein in plan view the innermost portion has a first outer contour, the outermost portion has a second outer contour, and the one or more intermediate portions each has a respective outer contour; and wherein the first outer contour, the second outer contour, and the respective outer contour are of a same type of shape and are of different sizes.
16. The dielectric resonator antenna of claim 11, wherein the one or more intermediate portions are each formed by a waffle structure with multiple grid cells.
17. The dielectric resonator antenna of claim 16, wherein the grid cells of the same intermediate portion are of generally the same size.
18. The dielectric resonator antenna of claim 12, wherein the one or more intermediate portions are each formed by a waffle structure with multiple grid cells; wherein the grid cells of the same intermediate portion are defined by walls of the same thickness, which is different from the thickness of the walls of the outermost portions; and wherein the grid cells of different intermediate portions are defined by walls of a respective thickness different from that of the grid cells in the other intermediate portions.
19. The dielectric resonator antenna of claim 18, wherein the thickness of the walls of the grid cells increases from the outermost portion towards the innermost portion such that among all the outermost portion and the one or more intermediate portion, the walls of the grid cells of the outermost portion has the smallest thickness, and the walls of the grid cells of the intermediate portion furthest away from the outermost portion and closest to the innermost portion has the largest thickness.
20. The dielectric resonator antenna of claim 10, wherein the outermost portion has a height higher than that of the innermost portion and the one or more intermediate portions.
21. The dielectric resonator antenna of claim 10, wherein the outermost portion has a maximum height higher than that of the innermost portion and that of the one or more intermediate portions.
22. The dielectric resonator antenna of claim 1, wherein the dielectric resonator element is additively manufactured.
23. The dielectric resonator antenna of claim 1, wherein the dielectric resonator element is arranged on the ground plane.
24. The dielectric resonator antenna of claim 1, wherein the ground plane is made of aluminium.
25. The dielectric resonator antenna of claim 1, wherein the feed network comprises a SMA connector with a coaxial feed probe inserted through a hole in the ground plane and surrounded by the innermost portion.
26. A communication device comprising the dielectric resonator antenna of claim 1.
27. A dielectric resonator antenna array, comprising: a ground plane; a plurality of dielectric resonator elements operably coupled with the ground plane; and a feed network operably coupled with the plurality of dielectric resonator elements for exciting the dielectric resonator antenna array to provide a wideband omnidirectional response; wherein the plurality of dielectric resonator elements each comprises a plurality of portions, the plurality of portions comprises: an innermost portion having a first effective dielectric constant; and an outermost portion arranged around the innermost portion and having a second effective dielectric constant different from the first effective dielectric constant; wherein the feed network is arranged to excite a plurality of transverse magnetic modes of the dielectric resonator antenna array, and the plurality of transverse magnetic modes comprises TM.sub.01δ mode, TM.sub.02δ mode, and TM.sub.03δ mode.
28. The dielectric resonator antenna array of claim 27, wherein the feed network comprises a plurality of sub-networks each associated with a respective dielectric resonator element.
29. The dielectric resonator antenna array of claim 27, wherein the plurality of dielectric resonator elements are additively manufactured.
30. A dielectric resonator antenna, comprising: a ground plane; a dielectric resonator element operably coupled with the ground plane; and a feed network operably coupled with the dielectric resonator element for exciting the dielectric resonator antenna to provide a wideband omnidirectional response; wherein the dielectric resonator element comprises a plurality of portions, the plurality of portions comprises: an innermost portion having a first effective dielectric constant; and an outermost portion arranged around the innermost portion and having a second effective dielectric constant different from the first effective dielectric constant; wherein the innermost portion is generally prismatic and the outermost portion is formed by a waffle structure with multiple grid cells.
31. The dielectric resonator antenna of claim 30, wherein the grid cells are defined by walls of the same thickness.
32. A dielectric resonator antenna, comprising: a ground plane; a dielectric resonator element operably coupled with the ground plane; and a feed network operably coupled with the dielectric resonator element for exciting the dielectric resonator antenna to provide a wideband omnidirectional response; wherein the dielectric resonator element comprises a plurality of portions, the plurality of portions comprises: an innermost portion having a first effective dielectric constant; an outermost portion arranged around the innermost portion and having a second effective dielectric constant different from the first effective dielectric constant; and one or more intermediate portions arranged around the innermost portion and nested between each other and between the innermost portion and the outermost portion; wherein the respective effective dielectric constant of the one or more intermediate portions is smaller than the first effective dielectric constant and larger than the second effective dielectric constant; and wherein the one or more intermediate portions are each formed by a waffle structure with multiple grid cells.
33. The dielectric resonator antenna of claim 32, wherein the grid cells of the same intermediate portion are of generally the same size.
34. A dielectric resonator antenna, comprising: a ground plane; a dielectric resonator element operably coupled with the ground plane; and a feed network operably coupled with the dielectric resonator element for exciting the dielectric resonator antenna to provide a wideband omnidirectional response; wherein the dielectric resonator element comprises a plurality of portions, the plurality of portions comprises: an innermost portion having a first effective dielectric constant; an outermost portion arranged around the innermost portion and having a second effective dielectric constant different from the first effective dielectric constant; and one or more intermediate portions arranged around the innermost portion and nested between each other and between the innermost portion and the outermost portion; wherein the one or more intermediate portions include multiple nested intermediate portions each having a respective effective dielectric constant, and wherein the respective effective dielectric constants are different and are smaller than the first effective dielectric constant and larger than the second effective dielectric constant; wherein the one or more intermediate portions are each formed by a waffle structure with multiple grid cells; wherein the grid cells of the same intermediate portion are defined by walls of the same thickness, which is different from the thickness of walls of the outermost portions; and wherein the grid cells of different intermediate portions are defined by walls of a respective thickness different from that of the grid cells in the outermost portion.
35. The dielectric resonator antenna of claim 34, wherein the thickness of the walls of the grid cells increases from the outermost portion towards the innermost portion such that among all the outermost portion and the one or more intermediate portions, the walls of the grid cells of the outermost portion has the smallest thickness, and the walls of the grid cells of the intermediate portion furthest away from the outermost portion and closest to the innermost portion has the largest thickness.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings in which:
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DETAILED DESCRIPTION
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(21) As shown in
(22) In this embodiment, the innermost central portion 102A is in the form of a solid, right annular cylinder having an annular cross section with a radius R.sub.1. The first intermediate portion 102B is annular with a radius R.sub.2 in plan view, and is formed by a waffle-like structure with multiple squared grid cells of generally the same size. The second intermediate portion 102C is annular with a radius R.sub.3 in plan view, and is formed by a waffle-like structure with multiple squared grid cells of generally the same size. The outermost portion 102D is annular with a radius R.sub.4 in plan view, and is formed by a waffle-like structure with multiple squared grid cells of generally the same size. The squared grid cells of the first intermediate portion 102B, the squared grid cells of the second intermediate portion 102C, and the squared grid cells of the outermost portion 102D are of generally the same size but with different wall thickness. In particular, the wall thickness of the grid cells of the first intermediate portion 102B is thicker than the wall thickness of the grid cells of the second intermediate portion 102C, which is in turn thicker than the wall thickness of the grid cells of the outermost portion 102D. As a result of the different wall thicknesses, the empty parts of the grid cells (the space defined by the walls) are of different sizes and the portions 102B to 102D have different air-filling ratios, which in turn leads to different effective dielectric constants. In this example, the effective dielectric constants of the innermost central portion 102A is ε.sub.r1, the effective dielectric constants of the first intermediate portion 102B is ε.sub.r2, the effective dielectric constants of the second intermediate portion 102C is ε.sub.r3, the effective dielectric constants of the outermost portion 102D is ε.sub.r4, where ε.sub.r1>ε.sub.r2>ε.sub.r3>ε.sub.r4. In other words, the effective dielectric constants of the dielectric resonator element 102 decrease from the innermost portion 102A towards the outermost portion 102D. The height h.sub.0 of the innermost central portion 102A and the intermediate portions 102B, 102C are generally constant and the same. The height h.sub.1 of the outermost portion 102D is generally constant and is higher than the height h.sub.0 of the other portions 102A-102C. This increased height at the outermost portion 102D improves matching. In this embodiment the dielectric resonator element 102 is integrally formed, e.g., additively manufactured using 3D printing technique.
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(24) In one example, the values of the parameters are as follows: R.sub.1=6 mm, R.sub.2=12.5 mm, R.sub.3=25.5 mm, R.sub.4=37.5 mm, ε.sub.r1=10.0, ε.sub.r2=8.25, ε.sub.r3=4.0, ε.sub.r4=2.5, h.sub.0=7.5 mm, h.sub.1=9 mm, l.sub.p=6.0 mm, 2R.sub.p=1.27 mm, R.sub.g=44 mm, and t=2 mm.
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(27) A retrieval method based on S-parameters was used to extract the effective dielectric constant ε.sub.eff of the grid cell unit.
ε.sub.eff=0.55t.sub.cε.sub.r−0.04ε.sub.r+1.3 (1)
from which t.sub.c can be easily determined for a required ε.sub.eff.
(28) To further test or evaluate the design in the above embodiments, a dielectric resonator antenna prototype 400 was made and tested. The prototype 400 is designed based on the antenna 100, 100′ of
(29) In the tests performed on the prototype, the reflection coefficient was measured using an E5071C vector network analyzer; whereas the radiation pattern, the antenna gain, and the antenna efficiency were measured using a Satimo Startlab System.
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(35) The dielectric resonator antenna of the above embodiments can be applied to an array design, to provide a dielectric resonator antenna array having a ground plane, multiple dielectric resonator elements operably coupled with the ground plane, and a feed network operably coupled with the dielectric resonator elements for exciting the dielectric resonator antenna array to provide a wideband omnidirectional response. The dielectric resonator elements each comprises a plurality of portions, including, at least, an innermost portion and an outermost portion arranged around the innermost portion. The innermost portion has a first effective dielectric constant. The outermost portion has a second, different effective dielectric constant. The dielectric resonator antenna array can be made similarly as the dielectric resonator antenna, using the method of
(36) The dielectric resonator antenna and the dielectric resonator antenna array of the above embodiments can be used in communication devices to provide large signal coverage. The communication devices may include wireless communication devices adapted for wireless communication (e.g., Wi-Fi routers adapted for Wi-Fi operations). The dielectric resonator antenna and the dielectric resonator antenna array of the above embodiments have a relatively low profile and are relatively compact. As a result they can be more readily used in miniaturised or small-scale systems or devices. In one specific embodiment above, the dielectric resonator antenna can be excited to provide three transverse magnetic modes, to provide relatively wide impedance bandwidth with stable omnidirectional radiation patterns. The relatively wide bandwidth may be advantageous in some applications.
(37) It will be appreciated that where the methods and systems of the invention are either wholly implemented by computing system or partly implemented by computing systems then any appropriate computing system architecture may be utilized. This will include stand-alone computers, network computers, dedicated or non-dedicated hardware devices. Where the terms “computing system” and “computing device” are used, these terms are intended to include any appropriate arrangement of computer or information processing hardware capable of implementing the function described.
(38) It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the invention as shown in the specific embodiments without departing from the scope of the invention as broadly described, so long as the dielectric resonator antenna can function as a wideband omnidirectional dielectric resonator antenna. Various possible options or alternatives have been non-exhaustively provided throughout the specification. The specifically described embodiments of the invention should therefore be considered in all respects as illustrative, not restrictive.
(39) For example, the dielectric resonator element(s) can be made into different shape(s), form(s), dimension(s), etc., other than those illustrated. The dielectric resonator element(s) can be made with different materials with different effective dielectric constants, other than those illustrated. The dielectric resonator element(s) can be formed with only the innermost and the outermost portions, optionally with addition intermediate portion(s), of different shape(s), size(s), form(s), material(s), effective dielectric constant(s), etc. The intermediate portion(s) and the outermost portion can be concentric rings of any shape (e.g., concentric triangular rings, concentric rectangular rings, concentric polygonal rings, concentric rounded rings, concentric circular rings, etc.). The intermediate portion(s) need not be comprised or composed of grid cell units, and in the examples that the intermediate portion(s) are comprised or composed of grid cell units, the grid cell units need not be cubical. The dielectric resonator element(s) can be but need not be made with ceramic materials. The dielectric resonator element(s) can be but need not be additively manufactured. The dielectric constant distributions (of different portions) of the dielectric resonator elements can be other values other than those illustrated. The shape(s), form(s), dimension(s), etc., of the ground plane can vary. The shape(s), form(s), dimension(s), etc., of the feed network can vary. The dielectric resonator element(s) can be made using any 3D printing techniques (e.g., in one go), or made using conventional tooling/molding/machining methods. The 3D printing techniques can be not limited to the fused deposition modelling technique. The feed network need not be a probe-feed network but can be a feed network for a different form. The ground plane need not be made with aluminium, and can be other material(s). The values of the illustrated parameters can be different, dependent on applications. Depending on the configurations and specific deigns, the dielectric resonator antenna can be used in indoor applications, in outdoor applications, or in both indoor and outdoor applications.