Electromagnetic waves do not perform well with abrupt changes in characteristic impedance because, when a propagating wave encounters a sudden change in the medium, a reflection is generated. Part of the received power is absorbed by the receiver and the rest is lost to the reflection. This has reduced the performance of antennas that are dielectrically loaded for miniaturization because, even when tuned at the proper frequency, the efficiency of the antenna is lowered due to the dielectric loading.
In an illustrative embodiment, a dielectric element is provided. The dielectric element includes, but is not limited to, a bottom surface, a top surface, and a plurality of cells formed vertically between the bottom surface and the top surface. Each cell of the plurality of cells includes a cell sidewall that extends below the top surface toward the bottom surface. The cell sidewall forms an aperture in the top surface and tapers from the top surface toward a center of a respective cell. Each cell sidewall is formed of a dielectric material.
In another illustrative embodiment, an antenna is provided. The antenna includes, but is not limited to, dielectric element, a conductive layer, a conducting pattern layer, and a plurality of vertical interconnect accesses (vias). The conductive layer includes, but is not limited to, a top conductive surface and a bottom conductive surface. The top conductive surface is on an opposite side of the first conductive layer relative to the bottom conductive surface and is mounted to the bottom surface of the dielectric element. The conductive layer is formed of a first conductive material. The conducting pattern layer is mounted to the top surface of the dielectric element and is formed of a second conductive material. Each vertical interconnect access (via) of the plurality of vias is formed of a third conductive material that extends through the dielectric element from the bottom surface to the top surface. Each via of the plurality of vias is connected to the conducting pattern layer. A first via may provide a first voltage value to the conducting pattern layer, and a second via may provide a second voltage value different than the first voltage value to the conducting pattern layer.
In another illustrative embodiment, a phased array antenna is provided. The phased array antenna includes, but is not limited to, a transmitter and a plurality of antennas mounted to a surface to form an array. Each antenna of the plurality of antennas is mounted to receive electrical energy from the transmitter.
Other principal features of the disclosed subject matter will become apparent to those skilled in the art upon review of the following drawings, the detailed description, and the appended claims.
Illustrative embodiments of the disclosed subject matter will hereafter be described referring to the accompanying drawings, wherein like numerals denote like elements.
Referring to
First dielectric element 100a may include a first plurality of cells 102. In the illustrative embodiment of
Each cell of the first plurality of cells 102 is defined by one or more walls. First dielectric element 100a may include a top surface 200 defined between a top of the walls of each cell of the first plurality of cells 102, a bottom surface 300 defined between a bottom of the walls of each cell of the first plurality of cells 102, and one or more element sidewalls 114 formed between top surface 200 and bottom surface 300. In the illustrative embodiment of
In the illustrative embodiment of
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In the illustrative embodiment, the slope is linear and tapers toward a center of first cell 102a. The slope may vary from zero that defines walls that extend straight down towards bottom wall 506 to a large value that generates a shallow depression, though top surface 200 always includes the top aperture for each cell. In alternative embodiments, the slope may be curved. The curve may be described by a polynomial such as the equation for a parabola. The slope further may change at discrete depth values in the z-direction.
Each cell of the first plurality of cells 102 has a top cell width 508, a bottom cell width 510, and a cell depth 512. In the illustrative embodiment, bottom wall 506 is located a depth 514 above bottom surface 300, and each cell is separated from each adjacent cell by a separation width 516. In an alternative embodiment, depth 514 may be zero such that bottom wall 506 is formed by bottom surface 300. In an alternative embodiment, each cell may not include bottom wall 506 but may include a bottom aperture defined through bottom surface 300. Bottom cell width 510 may be approximately zero such that the sidewalls meet at cell depth 512 at a center of the respective cell.
A first pattern layer 110 may be formed on top surface 200 of first dielectric element 100a. In the illustrative embodiment, first pattern layer 110 has a circular shape though first pattern layer 110 may form any shape of any size on top surface 200 of first dielectric element 100a. In an illustrative embodiment, first pattern layer 110 may be formed of a conductive material such as copper plated steel, silver plated steel, silver plated copper, silver plated copper clad steel, copper, copper clad aluminum, steel, etc., though other materials may be used in alternative embodiments. A size of the top aperture of each cell of the first plurality of cells 102 may be selected to provide a sufficient mechanical support for first pattern layer 110.
In the illustrative embodiments, the exterior walls of first dielectric element 100a and the walls of each cell of the first plurality of cells 102 may be formed of one or more dielectric materials that may include foamed polyethylene, solid polyethylene, polyethylene foam, polytetrafluoroethylene, etc. In an alternative embodiment, an element may be formed similar to first dielectric element 100a though using a different material such as a type of plastic, metal, etc. The exterior walls of first dielectric element 100a and the walls of each cell of the first plurality of cells 102 further may be formed of different materials that change in any of the x-direction, the y-direction, and/or the z-direction. For example, first dielectric element 100a may be formed using a 3D printer.
By varying a size of the aperture as each cell progresses downward in the z-direction, the density of the material and hence the effective dielectric constant of the material may slowly vary to avoid an abrupt change in characteristic impedance of the air-substrate boundary above top surface 200. Benefits when first dielectric element 100a is used as part of an antenna are an improved return loss reflected by first pattern layer 110, an improved efficiency of the antenna, and a lower weight.
Referring to
Second dielectric element 100b is similar to first dielectric element 100a though second dielectric element 100b includes fewer cells, and the cells have circular apertures in the x-y plane throughout the z-direction. Second dielectric element 100b may include a second plurality of cells 600. In the illustrative embodiment of
Each cell of the second plurality of cells 600 is defined by one or more walls. Second dielectric element 100b may include top surface 200 defined between a top of the walls of each cell of the second plurality of cells 600, bottom surface 300 defined between a bottom of the walls of each cell of the second plurality of cells 600, and one or more element sidewalls 114 formed between top surface 200 and bottom surface 300. In the illustrative embodiment of
In the illustrative embodiment of
Referring to
Each cell of the second plurality of cells 600 has a top cell width 1206, a bottom cell width 1208, and a cell depth 1210. In the illustrative embodiment, each cell is separated from each adjacent cell by a separation width 1212.
In the illustrative embodiments, the exterior walls of second dielectric element 100b and the walls of each cell of the second plurality of cells 600 may be formed of one or more dielectric materials that may include foamed polyethylene, solid polyethylene, polyethylene foam, polytetrafluoroethylene, etc. In an alternative embodiment, an element may be formed similar to second dielectric element 100b though using a different material such as a type of plastic, metal, etc. The exterior walls of second dielectric element 100b and the walls of each cell of the second plurality of cells 600 further may be formed of different materials that change in any of the x-direction, the y-direction, and/or the z-direction. For example, second dielectric element 100b may be formed using a 3D printer.
By varying a size of the aperture as each cell progresses downward in the z-direction, the density of the material and hence the effective dielectric constant of the material may slowly vary to avoid an abrupt change in characteristic impedance of the air-substrate boundary above top surface 200. Benefits when second dielectric element 100b is used as part of an antenna are an improved return loss reflected by first pattern layer 110, an improved efficiency of the antenna, and a lower weight.
Referring to
Conducting layer 1400 may be formed of a sheet of conductive material such as copper plated steel, silver plated steel, silver plated copper, silver plated copper clad steel, copper, copper clad aluminum, steel, etc. Conducting layer 1400 may be connected to a fixed potential that may be, but is not necessarily, a ground potential. Conducting layer 1400 may be generally flat or formed of ridges or bumps. For illustration, conducting layer 1400 may be formed of a flexible membrane coated with a conductor. Conducting layer 1400 is formed on bottom surface 300 of third dielectric element 100c.
A first vertical interconnect access (via) 1402 connects to second pattern layer 1302 through a cell of third dielectric element 100c. A second via 1404 connects to a wire 1406 connected to first via 1402 and second pattern layer 1302. Second via 1404 is also formed through a cell of third dielectric element 100c. Electrical energy is provided to second pattern layer 1302 through second via 1404 so that first antenna 1300 forms a bowtie antenna. As understood by a person of skill in the art, dimensions and/or materials associated with first antenna 1300 may be selected based on λ0, a wavelength in free space at a center frequency selected for operation of first antenna 1300. Depending on a type of structure formed by second pattern layer 1302, one or more vias may be positioned at different locations.
First antenna 1300 was simulated using ANSYS HFSS, which is 3D electromagnetic simulation software for designing and simulating high-frequency electronic products, for first antenna 1300 selected to operate at a center frequency of 2.4 gigahertz (GHz). The simulated first antenna 1300 had top cell width 508 equal to 73.17 mils, bottom cell width 510 equal to 5 mils, cell depth 512 equal to 390 mils width 104 and height 106 equal to 1.93 inches, and a dielectric constant value of 2.17 Farad/meter.
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Feed antenna 2102 may be a dipole antenna, a monopole antenna, a helical antenna, a microstrip antenna, a patch antenna, a fractal antenna, a horn antenna, a slot antenna, an end fire antenna, a parabolic antenna, etc. Feed antenna 2102 is positioned a focal distance 2108, fd, from a top surface 2112 of reflective array antenna 2104. Feed antenna 2102 is configured to receive an analog or a digital signal, and in response, to radiate a spherical radio wave toward top surface 2112. Feed antenna 2102 also may be configured to receive the spherical radio wave from top surface 2112 and to generate an analog or a digital signal in response.
The plurality of antenna elements 2110 may be arranged to form a one-dimensional (1D) or a two-dimensional (2D) array in any direction. The plurality of antenna elements 2110 may form variously shaped apertures including circular, rectangular, square, elliptical, etc. The plurality of antenna elements 2110 can include any number of antenna elements.
The spherical radio wave reaches different portions of top surface 2112 at different times. The plurality of antenna elements can be considered to be a plurality of pixels each of which may provide a selected phase shift within the frequency band of interest. Thus, each antenna element of the plurality of antenna elements can be phase shifted such that the spherical radio wave is re-radiated in the form of a planar wave that is parallel to top surface 2112, or vice versa. Given aperture diameter 2106 and focal distance 2108, a phase shift profile to form the planar wave directed to a specific angle can be calculated as understood by a person of skill in the art.
Referring to
The plurality of antenna elements 2208 is arranged to form a 1D or a 2D phased array antenna as shown on the left side. The phased array antenna has an aperture length 2218 in a vertical plane and may further have an aperture width (not shown) in a horizontal plane. A center of each antenna element of the plurality of antenna elements 2208 may be separated a distance 2220 from a center of each adjacent antenna element in any direction. The plurality of antenna elements 2208 include a dielectric layer formed of a plurality of dielectric elements such as first dielectric element 100a, second dielectric element 100b, third dielectric element 100c, and/or fourth dielectric element 100d.
As understood by a person of skill in the art, the phased array antenna can electronically change a pointing direction 2212 of a main beam relative to a boresight vector 2210 by changing a phase shift applied by each phase shifter to a respective antenna element under control of controller 2202. Controller 2202 thereby electronically steers the main beam to different directions without moving the phased array antenna. The electromagnetic energy associated with the electrical energy field input from transceiver 2201 is fed to each phase shifter of the plurality of phase shifters 2206 through feed line network 2204. Based on the pointing direction 2212 of the main beam selected, controller 2202 defines a phase shift value to be generated by each phase shifter of the plurality of phase shifters 2206. With the phase relationship defined by controller 2202 for each phase shifter of the plurality of phase shifters 2206, the radio waves from each of the antenna elements add together to increase the radiation in the pointing direction 2212, while canceling to suppress radiation in undesired directions. The lines from each antenna element represent a wave front of the electromagnetic waves emitted by each antenna element. The individual wave fronts are spherical, but they combine in front of the phased array antenna to create a plane wave, a beam of radio waves travelling in the pointing direction 2212.
As used herein, the term “mount” includes join, unite, connect, couple, associate, insert, hang, hold, affix, attach, fasten, bind, paste, secure, bolt, screw, rivet, solder, weld, glue, form over, form in, layer, mold, rest on, rest against, etch, abut, and other like terms. The phrases “mounted on”, “mounted to”, and equivalent phrases indicate any interior or exterior portion of the element referenced. These phrases also encompass direct mounting (in which the referenced elements are in direct contact) and indirect mounting (in which the referenced elements are not in direct contact, but are connected through an intermediate element). Elements referenced as mounted to each other herein may further be integrally formed together, for example, using a molding or a thermoforming process as understood by a person of skill in the art. As a result, elements described herein as being mounted to each other need not be discrete structural elements. The elements may be mounted permanently, removably, or releasably unless specified otherwise.
The word “illustrative” is used herein to mean serving as an example, instance, or illustration. Any aspect or design described herein as “illustrative” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Further, for the purposes of this disclosure and unless otherwise specified, “a” or “an” means “one or more”. Still further, using “and” or “or” in the detailed description is intended to include “and/or” unless specifically indicated otherwise. The illustrative embodiments may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed embodiments.
Any directional references used herein, such as left side, right side, top, bottom, back, front, up, down, above, below, etc., are for illustration only based on the orientation in the drawings selected to describe the illustrative embodiments.
The foregoing description of illustrative embodiments of the disclosed subject matter has been presented for purposes of illustration and of description. It is not intended to be exhaustive or to limit the disclosed subject matter to the precise form disclosed, and modifications and variations are possible in light of the above teachings or may be acquired from practice of the disclosed subject matter. The embodiments were chosen and described in order to explain the principles of the disclosed subject matter and as practical applications of the disclosed subject matter to enable one skilled in the art to utilize the disclosed subject matter in various embodiments and with various modifications as suited to the particular use contemplated.