JP2016528840A - High dielectric antenna array - Google Patents

Abstract

Systems and methods for wirelessly transmitting signals via an antenna phased array are disclosed. In order to reduce the distance between individual antennas in the array, the antennas are embedded in a high dielectric material in addition to being placed orthogonal to each other. Both of these features prevent one or more antennas from coupling. In addition, the wires are coated with a high dielectric material to refract the RF signal around, allowing the antenna on the center side of the array to successfully transmit the signal across the other layers. [Selection] Figure 3

Description

  The present invention relates generally to the field of wireless signal transmission, and more particularly to new and useful systems and methods for industrial antenna arrays.

  A number of useful applications are based on the transmission of radio pulses. Examples include radar detection using transmitted and reflected pulsed (type) microwave signals, as well as medical ablation procedures that utilize pulsed microwaves to ablate target body tissue. .

  US patent application Ser. No. 14 / 171,750, filed Feb. 3, 2014, by Ossia Inc., the contents of which are fully incorporated herein by reference, is a transmission that optimizes the transmission of wireless power to multiple receivers. The machine was disclosed. To transmit power wirelessly, a phased array transmitter is used to direct high frequency (RF, radio frequency) power.

  The transmission efficiency of a phased array transmitter is proportional to the number of antennas in the array. For example, in order to achieve efficiencies exceeding 90%, a 2.4 GHz signal transmitted at a distance of 5 m with high efficiency theoretically requires about a million antennas in the array. However, it is very difficult to place a million antennas within 5 m away from the target. Each antenna requires its own space to avoid direct coupling with the resident antenna, so the size of the array can be several times the distance of 5 meters. In addition, as the array grows, the efficiency disappears and most antennas will be out of the 5 meter range. Therefore, there is a need for means to reduce the size of the array while overcoming the constraints introduced by the proximity of the antenna.

  Means for reducing the size of the array while overcoming the constraints introduced by antenna proximity are employed in embodiments of the present invention.

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  The present invention provides a means for reducing the size of the array while overcoming the constraints introduced (or induced) by the proximity of the antenna. In order to reduce the distance between the individual antennas in the array, in addition to placing the antennas orthogonal to each other, the antennas are embedded in a high dielectric material, but both features are more than one Eliminate antenna coupling. In addition, a wire is wrapped in a high dielectric material to refract the RF signal around, allowing the antenna at the center of the array to successfully transmit the signal beyond the layers above it. .

  The various features of the invention described above can be implemented alone or in combination. These as well as other features of the present invention are described in further detail in the following detailed description of the invention with the following figures.

  In order to more clearly describe the present invention, several embodiments will be described by way of example with reference to the following drawings.

FIG. 1 is a table showing different frequencies and corresponding wavelengths, and transmission ranges for various wireless applications. FIG. 2 shows a size comparison between an antenna in the air and a significantly smaller antenna embedded in a high dielectric material. FIG. 3 is shown in broken lines with some antenna components (elements) penetrating from the front surface (front surface) to the rear surface (back surface) of the printed circuit board. ) Shows the placement of the antenna (s) on the placed printed circuit board (PCB). FIG. 4A shows the wire density required to prevent deflection of RF radiation in the air. FIG. 4B shows the wire density required to prevent deflection of the RF radiation when the wire is embedded in a dielectric material of dielectric constant p. FIG. 5 shows an exemplary dipole antenna etched using the same technique as etching conductive traces on a PCB. FIG. 6 is a cross-sectional view of a PCB having four layers. The central two layers are used for antenna etching, and the antenna is embedded in the PCB dielectric material. FIG. 7 is a cross-sectional view of a PCB containing conductive wires in which the inner layer of the PCB is surrounded by air or other low dielectric constant material. FIG. 8A illustrates the effect of a large total internal reflection angle so that the signal faces air as it attempts to leave the high dielectric material and the signal stays in the high dielectric material. FIG. 8B is similar to an optical lens coating technique in which a high dielectric material with multiple layers of relatively low dielectric constant allows internal signals to escape from the high dielectric material into the air without the effect of a large total internal reflection angle. Illustrate the technology. FIG. 9 illustrates an orthogonally oriented antenna according to one preferred embodiment of the present invention. FIG. 10 illustrates the quasicrystal arrangement of the antenna. FIG. 11 illustrates one preferred embodiment of the overall system of the present invention.

[Detailed description]
The present invention will be described in detail below with reference to several embodiments of the invention illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, those skilled in the art will appreciate that the embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and / or well known structures have not been described in detail in order not to unnecessarily obscure the present invention. The features and advantages of the embodiments will be understood with reference to the drawings and the following description.

  The aspects, features and advantages of exemplary embodiments of the present invention will be better understood from the following description with reference to the accompanying drawings. The described embodiments of the invention provided herein are for illustrative purposes only and are not intended to limit the invention and are provided as examples only. It will be obvious to the technical engineer. All features disclosed in this specification can be replaced by other features serving the same or similar purposes, unless expressly stated otherwise. Accordingly, it is envisioned that numerous other embodiments of those modifications will fall within the scope of this invention and its equivalents as defined herein. Thus, for example, "will be ...", "will not be ...", "... will", "will not ...", "...・ Must be ”,“ must not be ”,“ first ”,“ first ”,“ next ”,“ follow ”,“ before ”,“ .. Independent and / or sequential terms such as “after”, “finally” and “finally” are meant to limit the scope of the present invention as the embodiments disclosed herein are merely illustrative Does not have.

  The size of the phased array antenna is directly proportional to the space between the elements (or elements) in the phased array. The space between these elements is determined by the physical theory involved in radio frequency (RF) transmission in the material in which the antenna elements are embedded, and it limits the extent to which the antennas can be placed close together.

  In the simplest case, two antennas facing each other can be arranged adjacent to each other by one wavelength. Beyond that, various adverse side effects due to proximity become a major problem and spoil the advantage of having two antennas. One of these side effects is that the two antennas function as one antenna, which is counterproductive. This is because the possibility of directing a radio signal with a phased array antenna relies on having a unique phase assigned to individual antenna elements. The antenna phases are carefully controlled and assumed to be different from each other. Thus, the minimum distance between antenna array elements determines the minimum size of the array.

  Since the minimum distance between antenna elements is directly related to the wavelength, and the wavelength is inversely proportional to the frequency, the frequency being transmitted and the medium (or medium) in which the antenna element is embedded are known. Thus, the size of the antenna array can be determined. There are several possible embodiments of the radio signal, each with a suitable frequency as shown in FIG. A chart (chart) 100 describes antennas used in different wireless usage forms 110. The frequency 120 is a frequency normally used for the wireless usage mode 110. Wavelength 130 is the approximate wavelength value in vacuum or air associated with frequency 120. For each wireless usage mode 110, a corresponding transmission range 140 when each transmitting 1 watt of power is presented.

  Within a general home or business environment, the frequency of the radio signal is in the range of 1 GHz to 8 GHz. One common frequency used is 2.4 GHz, corresponding to a wavelength of 12.5 cm in vacuum or air, as shown in diagram 100 of FIG. For example, if the number of antenna elements on one side of a cube-shaped phased array is 40, the length of each side of the cube is about 16 feet (12.5 cm × 40 = 5 m) under this general frequency. It will be. This is truly a home-sized array. However, there is no room for ordinary households in this huge cube. This is because the array must have a group of antenna elements spaced about 5 inches apart in all three dimensions. Thus, a method must be discovered that preserves the advantageous properties of the array while reducing the distance between antenna elements.

  The distance involved in the above calculation is based on the electromagnetic wave length in vacuum or air. An important factor in calculating these distances is closely related to the permittivity of free space. If the dielectric constant of the material forming the body of the antenna array can be changed, it can affect the distance involved while keeping the frequency constant. This is due to the reduced speed of electromagnetic waves in a dielectric medium, which usually has a higher dielectric constant than that of vacuum or air, due to the high dielectric constant of the dielectric medium.

  However, the dielectric medium must be carefully selected. This is because there are many other side effects that can be introduced by different materials. For example, the metal can have an advantageous high dielectric constant. However, metal also introduces a number of inconvenient attributes that conflict with usage. Metals can reflect radio frequency (RF), absorb RF radiation and convert it to heat. The metal is processed into various shapes to be used for constructing a transmission (transmission) / reception (reception) antenna, and therefore cannot be used as a medium (or medium) in which an antenna element is embedded.

  Although there are other types of materials with promising high dielectric constants, they create other problems such as attenuation of RF energy passing through them. High weight can be another problem. These properties are also not desired in the present application.

  However, there are types of materials that have the desired dielectric constant and do not have any disadvantages in the physical field. Some of them are even available without the prohibitive costs. These are Rogers materials from which RF4 fiberglass circuit boards (and other products) are made. These materials have a dielectric coefficient in the range of p = 3 to p = 30. The dielectric constant of p = 30 means that the distance term in the chart 100 of FIG. 1 (ie wavelength 130 and transmission range 140) can be reduced or divided by a factor of √30 at the same frequency 120 of the chart 100 again. ) Means. This size reduction is illustrated in FIG. As an example, consider the effect of material dielectric constant p on a quarter-wavelength antenna system 200. The quarter wave antenna 210 is shown in FIG. The quarter-wave antenna 210 is in the air and has a length l (el). A quarter-wave antenna 220 is shown in FIG. 2 (b), where the material used has a dielectric constant p. The length of the quarter-wave antenna 220 is reduced to a factor (or multiple) of 1 / √p (1 for root p).

  If we consider a cube-shaped array made of the above-described quarter-wave antenna system 200 and containing 40 (elements) embedded in a medium having a dielectric constant of 30, the size of this cube is divided into three dimensions. , By dividing by a factor of √30, a new cube with a height, width and depth (depth) of about 36 inches is obtained. The actual new calculation is (12.5 cm × 40 / √30 = 0.91 m = 35.9 inches), and each edge (side) is a cube below 36 inches. Furthermore, considering that the packing in the high-density state of the antenna can be about half a wavelength, it is possible to halve the numerical value to 18 inches.

  In order to accommodate a large number of antennas in this cube, one embodiment of the present invention places them in a particular configuration on a printed circuit board (PCB). In this structure, the antenna is laid in three dimensions to cover all types of deflected signals, as illustrated by the antenna structure 300 shown in FIG. Components of the antenna that penetrate the circuit board from the front side to the back side are represented by broken lines. This antenna structure 300 will place a large number of antennas in close proximity while minimizing mutual interference.

  FIG. 4A assumes that the wave deflection is perpendicular to the orientation of the wire, assuming that the “wave” 410 has a distance 430 of length d or less equal to the RF radiation wavelength 440. It shows how the deflected RF radiation can be blocked if blocked by a conductive wire 420.

  According to one embodiment of the present invention, if the wire 460 is embedded in a dielectric material with a dielectric constant p, the spacing 470 is reduced to d / √p and densified as shown in FIG. 4B. Line (line spacing). Therefore, the minimum size of the entire array device is reduced.

  Thus, with the array size regulated, one embodiment of the present invention embeds the wires that supply and control the circuit on the PCB in a dielectric material with a dielectric constant p (p is substantially greater than 1). It is recommended that

  As shown in FIG. 5, one embodiment of the present invention has an antenna 500 on the PCB that is etched using the same technique for etching conductive traces on the PCB, adding components. The antenna is built in the circuit board, and the manufacturing cost of the antenna is reduced. Patterns 510, 520 and 530 are exemplary dipole antennas that can be easily constructed on a PCB according to this embodiment of the invention.

  As shown in FIG. 6, one embodiment of the present invention in form 600 is for a PCB with multiple layers to etch the antenna to ensure that the antenna is fully embedded within the dielectric material of the PCB. Inner layers 610, 620, 630, 640 are used.

  FIG. 7 shows traces 710 that are hardly visible in the PCB material surrounded by air gaps 720 or other low dielectric materials, thus making them highly reflective spaces. However, this is useful because most signals are reflected at the boundary due to movement from a high dielectric material to a low dielectric material.

  As shown in FIG. 8A, a signal 810 that attempts to leave a high dielectric material 830 facing a low dielectric medium 820, such as air, exhibits a high total internal reflection angle 840, causing the signal to stay in the high dielectric material 830. However, this is inconvenient for the antenna array.

  To circumvent this problem, one embodiment of the present invention includes the embodiment of FIG. 8B. In this embodiment, the outer layer of the PCB is made of a material 860 with a dielectric constant lower than that of the inner layer 870 made of a high dielectric material. The internal signal 880 can then escape from the high dielectric material 870 into the air without encountering and being affected by the high total internal reflection angle, as in the case of optical lens coatings.

  A further reduction is feasible if one considers that the mutually orthogonal antenna pairs do not interfere with each other. In this way, five antennas can be placed in the same volume as one antenna with matched antennas.

  These orthogonal orientations also have an advantage that a signal can be sent to a client device (device corresponding to a customer) with an arbitrary directionality in three dimensions. According to the present invention, any angle can be used for antenna orientation.

  As shown in FIG. 9, even with a 45 ° orientation 900, it is effective due to the two shape patterns that can be arranged one above the other. These patterns not only have 45 ° layout antennas, but the two patterns can be stacked one above the other on alternate layers, and the two arrays of antennas will be orthogonal to each other.

  When multiple antennas are placed close together and all antennas transmit RF signals in various directions, the antenna near the center of the cubic array is a non-disturbing path for sending signals to client devices outside the array. It would be easy to imagine that you can't have. After all, the number of other antennas is important. One embodiment of the present invention has over 150 other layers of antennas in the path from the center of the million antenna array, and the signal only needs to avoid all other antennas during the outing process. Rather, considerable power and ground wiring supplied to these antenna circuits must also be avoided.

  What is needed is to create an RF signal that travels in a straight line and bends so that all other wiring can be avoided sufficiently in the entire process in the direction of travel. The wire can be repeatedly coated with progressively higher dielectric materials in the manner of making a candle. The RF signal path is bent by a high dielectric material so that the light beam is bent by the glass. If the RF is sufficiently refracted through the interface between the layers of the continuously coated dielectric material, all RF signals from the antenna will pass around the inner wire. The array is now powered by a wire that is essentially “invisible” to the RF that passes through it.

  This creates a trace surrounded by air gaps or some other low dielectric material in the PCB material, such as the embodiment shown in FIG. 7, making the trace in the wiring board a highly reflective space. It is improved by making it possible. In this signal transfer from a high dielectric material to a low dielectric material, most of the signal will be reflected at its boundary and travel around a potentially disturbing object such as a wire. This may affect the performance of the antenna receiving the signal, since only the signal aimed directly at the center of the wire will not deflect around the antenna lead.

  As shown in FIG. 10, one preferred embodiment of the present invention recommends that the antennas of the array 1000 be arranged in a quasicrystalline form 1010 that is non-periodic (ie, non-repetitive) in all directions. Image 1020 shows all the integrations of the five antennas housed in a pentagon and shows the non-periodicity of this arrangement. This non-periodic design maintains antenna density throughout the array layout, while preventing the antennas from coupling due to excessive close proximity. In addition, such an aperiodic design suppresses the natural directivity of the phased array and allows the delivery of increased power in any direction by suppressing the natural (ie, inconvenient) directionality. .

  Although the above quasicrystalline array is non-periodic, having several arrays of the same design in the layer will in any case create periodic orientation. This is inconvenient for signal amplification. To circumvent this problem, one preferred embodiment of the present invention has each layer of the array made from quasicrystalline designs of different sections, thus avoiding the same stacking pattern throughout the layer. is there.

  Another problem is that the central part of the quasicrystal design is usually symmetric at a given angle, which weakens the aperiodic nature of those patterns. In order to avoid this problem, one embodiment of the present invention utilizes a portion of the quasicrystal design that is further away from the center.

  FIG. 11 illustrates one preferred embodiment of the overall system 1100 of the present invention. The system is provided in a three-dimensional form that includes a plurality of PCBs 1110, each of which includes a high dielectric material that houses an array of densely packed antennas 1120 that are relative to each other. The antennas are arranged in a quasicrystal pattern. These PCBs are electrically coupled by internal PCB connections including wires 1130 housed in a high dielectric material. These PCBs are housed in a housing 1140 made of a material that is permeable to RF so as not to interfere with signal transmission. This container can be made of a material having a dielectric constant lower than that of PCB.

  The present invention provides a system and method for reducing the size of a phased array of antennas without sacrificing the range of wireless signal transmission. A wireless signal can include power, data, or any other signal that can be transmitted wirelessly. The advantages of such a system include the ability to store the phased array in a limited space, enabling wireless signal transmission to be used in a wider range of situations, such as in a home or car.

  Although the invention has been described with reference to several embodiments, there are alternatives, modifications, substitutions, and equivalents within the scope of the invention. Although sub-section titles are provided here to aid in the description of the invention, they are merely illustrative and are intended to limit the scope of the invention. Not.

  It should be understood that there are many alternative ways of utilizing the method and apparatus of the present invention. Accordingly, the claims should be construed to include all such alternatives, modifications, substitutions and equivalents that fall within the spirit and scope of the invention.

Claims (15)

A compact antenna array configured to transmit signals wirelessly,
A plurality of antenna elements forming a phased array antenna and disposed in an arrangement substantially perpendicular to each other;
A dielectric insulator having a substantially high dielectric constant provided so as to substantially embed the plurality of antenna elements, the space between each of the plurality of antenna elements being reduced, and the plurality of antennas Enhance the signal transmission by refracting the RF signal around the plurality of antenna elements and allowing the element to a subset of the plurality of antenna elements near the center of the phased array antenna beyond the other layers of the antenna elements. A substantially high dielectric constant dielectric insulator that allows the signal to be transmitted successfully;
An antenna array comprising:   The antenna array of claim 1, wherein the high dielectric constant dielectric insulator has a dielectric constant substantially greater than three.   The antenna array of claim 1, wherein the phased array antenna is coupled by a conductive wire coated with a high dielectric constant dielectric material.   The antenna array of claim 1, wherein the phased array antenna includes traces in a circuit board, a portion of the traces being surrounded by air gaps or some other low dielectric constant dielectric material. .   The antenna array of claim 2, wherein the high dielectric constant dielectric material is disposed adjacent to a region of the low dielectric constant material to enhance signal transmission.   The antenna array according to claim 1, wherein the antenna element is etched in a gap layer of a circuit board.   The antenna array according to claim 1, wherein the pattern of the antenna element is a quasicrystal. A method of transmitting wireless communication signals and wireless power transmission,
Emitting radio frequency (RF) signals from a phased array of antenna elements having different phases that are substantially orthogonal, avoiding signal interference between said antenna elements;
Refracting the RF signal around a wire coupling the phased array of antenna elements to enhance signal transmission, the antenna element being a subset of the array of antenna elements substantially near the center of the phased array of antenna elements Successfully transmitting signals across other layers of the phased array of
A method characterized by comprising.   The method of claim 9, wherein the array of antenna elements is embedded by a dielectric insulator having a substantially high dielectric constant that is substantially greater than three.   The method of claim 9, wherein the phased array antenna elements are coupled by a conductive wire coated with a high dielectric constant dielectric material.   The phased array of antenna elements includes a trace in a circuit board, a portion of the trace being surrounded by an air gap or some other low dielectric constant dielectric material. Method.   The method of claim 10, wherein the high dielectric constant dielectric material is adjacent to a region of low dielectric constant material to enhance signal transmission.   The method of claim 1, wherein the phased array of antenna elements is etched into a gap layer of a circuit board.   The method of claim 1, wherein the phased array pattern of the antenna elements is a quasicrystal. A method for producing an element of a phased array antenna,
Etching an array of elements substantially perpendicular to each other directly onto a high dielectric constant circuit board;
Forming the array of elements in a gap layer of the circuit board;
Forming a gap between the layer of high dielectric constant material and the layer of low dielectric constant material;
Coating a wire coupling the array of elements with a dielectric material of high dielectric constant;
A method comprising the steps of:

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