Mountable antenna elements for dual band antenna
10224621 ยท 2019-03-05
Assignee
Inventors
Cpc classification
H01Q21/28
ELECTRICITY
H01Q1/50
ELECTRICITY
H01Q9/00
ELECTRICITY
International classification
H01Q1/50
ELECTRICITY
H01Q21/28
ELECTRICITY
Abstract
A mountable antenna element is constructed as an object from a single piece of material and can be configured to transmit and receive RF signals, achieve optimized impedance values, and operate in a concurrent dual-band system. The mountable antenna element may have one or more legs, an RF signal feed, and one or impedance matching elements. The legs and RF signal feed can be coupled to a circuit board. The impedance matching elements can be utilized to create a capacitance with a portion of the circuit board and thereby optimize impedance of the antenna element at a desired operating frequency. The mountable antenna includes features that enable it for use in concurrent dual band operation with the wireless device. Because the mountable antenna element can be installed without needing additional circuitry for matching impedance and can be constructed from a single piece of material, the antenna element provides for more efficient manufacturing.
Claims
1. A reflector mountable to a printed circuit board (PCB) for reflecting a radio frequency (RF) signal comprising: a first side and a second side disposed at an angle of about ninety degrees from one another; a base having an end, wherein a first end of the first side and a first end of the second side meet at the base end and extend separately to a respective outer end; a plurality of mounting pins at the second end of the first side in a first plane for positioning the reflector to respective holes on a surface of the PCB; a coupling plate at the second end of the second side in a second plane perpendicular to the first plane and parallel to the surface of the PCB for mounting the reflector to the surface of the PCB; and a switch for switchably coupling the coupling plate to a ground layer of the PCB, wherein when the switch is open, the reflector does not change a radiation pattern of an antenna element mounted to the PCB and directed at the reflector, and when the switch is closed the reflector is connected to the ground layer to cause the reflector to reflect the radiation pattern.
2. The reflector of claim 1, wherein the first side, the second side, the base and the plurality of mounting pins are formed by bending a single piece of substantially T shaped metal by about ninety degrees at a middle of the single piece of substantially T shaped metal.
3. The reflector of claim 1, wherein the coupling plate extends parallel to the PCB.
4. The reflector of claim 1, wherein coupling plate extends at an angle of about ninety degrees from the second side.
5. The reflector of claim 1, wherein the single piece of substantially T shaped metal includes a first arm extending in a first direction and a second arm extending in a second direction, the first direction and the second direction being at least ninety degrees apart.
6. The reflector of claim 1, wherein the coupling plate is coupled to the switch, the switch element engaging or disengaging the reflector.
7. The reflector of claim 1, wherein the antenna element includes one or more impedance matching elements extending downward towards the PCB.
8. The reflector of claim 7, wherein the one or more impedance matching elements are part of a single object comprising the antenna element.
9. The reflector of claim 8, wherein the one or more impedance matching elements are positioned downward away from a top surface of the antenna element and towards the ground layer of the PCB.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(17) A mountable antenna element constructed as a single element or object from a single piece of material can be configured to transmit and receive RF signals, achieve optimized impedance values, and operate in a concurrent dual-band system. The mountable antenna element may have one or more legs, an RF signal feed, and one or more impedance matching elements. The legs and RF signal feed can be coupled to a circuit board. The impedance matching elements can be utilized to create a capacitance with a portion of the circuit board thereby optimizing impedance of the antenna element at a desired operating frequency. The mountable antenna can also include one or more stubs that enable it for use in concurrent dual band operation with the wireless device. Because the mountable antenna element can be installed without the need for additional circuitry to match impedance and can be constructed as a single object or as a single piece of material, the mountable antenna element allows for more efficient manufacturing.
(18) The one or more impedance matching elements of the mountable antenna element are configured to achieve optimized impedance for the mountable antenna element. The impedance matching elements are part of the single object comprising the antenna element, and positioned downward away from a top surface of the mountable antenna and towards a circuit board ground plane. The one or more impedance matching elements may each achieve a capacitance with respect to the ground plane, wherein the capacitance achieves the impedance matching for the antenna element. The impedance matching for the mountable antenna allows for a cleaner and more efficient signal to be broadcast (and received) at a desired frequency for the antenna element.
(19) The legs of the antenna element may each contain one or more stubs in a close proximity of the leg. The stubs are configured to create an open circuit in the leg for a particular frequency. The open circuit prevents current from being induced up the leg and into the mountable antenna element thereby affecting radiation of a smaller sized antenna due to a larger antenna element associated with the leg. The larger mountable antenna element is transparent, or does not interfere with a smaller mountable antenna element, as a result of preventing an induced current in the larger antenna element due to radiation from the smaller antenna element.
(20) A reflector may also be mounted to a circuit board having a mountable antenna element. The reflector can reflect radiation emitted by the antenna element. The reflector can be constructed as an element or object from a single piece of material and mounted to the circuit board in a position appropriate for reflecting radiation emitted from the antenna element. The reflector can include one or more pins and a plate for installing the reflector to the circuit board. When reflector pins are inserted into designated holes in the circuit board and the reflector plate is in contact with a circuit board pad, the reflector may stand on its own. As a result, the process of securing the reflector to the circuit board is made easier.
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(22) The data I/O module 205 of
(23) The antenna selector 220 of
(24) The mountable antenna and reflectors 250 include at least one antenna element and at least one reflector and can be located at various locales on the circuit board of a wireless device, including at the periphery of the circuit board. A mountable antenna element may also be used in a wireless device without a reflector. Each set of mountable antenna and reflectors 250 may include an antenna element configured to operate at one or more frequencies. Each mountable antenna may be configured to radiate at a particular frequency, such as 2.4 GHz or 5.0 GHz. To minimize any potential interference between antennas radiating at different frequencies within a wireless device, mountable antennas radiating at different frequencies can be placed as far apart as possible on a circuit board, for example at opposite corners of a circuit board surface as is illustrated in
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(26) An antenna element can be coupled to the circuit board 300 at coupling pads 310 and 340. A coupling pad is a pad connected to circuit board circuitry (for example a switch 230 or ground) and to which the antenna element can be connected, for example via solder. The antenna element can include a coupling plate having a surface that, when mounted to the circuit board, is roughly parallel and in contact with the circuit board coupling pads 310 and 340. A coupling plate is an antenna element surface (e.g., a surface at the end of an antenna element leg) that may be used to connect the antenna element to a couple pad. Antenna elements having a coupling plate (e.g., coupling plate 470) are illustrated in
(27) A circuit board mounting pad 310 can include one or more coupling pad holes 315. A coupling pad hole 315 is an aperture or opening that extends from the surface into one or more layers of the circuit board. The coupling pad holes can receive an antenna element pin to help the secure antenna element to the circuit board 300. The antenna element can be positioned in place on the circuit board 300 by inserting one or more pins of the antenna element into a circuit board coupling pad hole 315. Once one or more antenna element pins are inserted into the appropriate coupling pad holes, the antenna element can be secured to the circuit board by means of soldering or some other coupling operation. An antenna element with one or more pins and a coupling plate is discussed in more detail with respect to
(28) A reflector can be mounted to the circuit board 300 at coupling area 320. Coupling area 320, as illustrated in
(29) The holes 330 of coupling area 320 are formed by an aperture or opening that extends from the surface into one or more layers of the circuit board and can be used to position a reflector in an appropriate position over coupling area 320. When a reflector has one or more pins inserted into corresponding holes 330 and a mounting plate (e.g., mounting plate 720 of
(30) A reflector that can maintain an upright position without external support, for example by a machine or person, allows for easy attachment of the reflector to the circuit board 300. A reflector with one or more pins and a coupling plate is discussed in more detail with respect to
(31) An antenna element and reflector can be designed in combination to operate at a desired frequency, such as 2.4 gigahertz (GHz) or 5.0 GHz.
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(33) The antenna element legs can be used to couple the antenna element to circuit board 300 (
(34) When the antenna element coupling plate 470 is connected to circuit board coupling pad 340 and a switch connecting the coupling pad 340 to radio modulator/demodulator 215 is open, no radiation pattern is transmitted or received by the mounted antenna element. When the switch is closed, the mounted antenna element is connected to radio modulator/demodulator 205 and may transmit and receive RF signals.
(35) The antenna element stubs 450 and 460 may increase the performance of the wireless device 100 when utilizing different antenna elements to operate at multiple frequencies simultaneously, which may be referred to as concurrent dual band operation. The mountable antenna elements that operate at a smaller frequency may be larger in size than the mountable antenna elements that operate at a larger frequency. The larger mountable antenna elements, in such an instance, can interfere with the operation of the smaller antenna elements. For example, when a smaller sized antenna element (e.g., the antenna element of
(36) To prevent the induced current, stubs 450 and 460 may create an open circuit when a radiation signal is received at the operating frequency of the smaller sized antenna element. Hence, when antenna element 400 is configured as a 2.4 GHz antenna element and operating on the same circuit board as a 5.0 GHz antenna element, stubs 450 and 460 are excited by the received 5.0 GHz radiation signal and form an open circuit at the base (the end of the leg that connects to the circuit board 300) of leg 455. The open circuit is created at the base of leg 455 at 5.0 GHz. By forming an open circuit for a 5.0 GHz signal at the base of leg 455, no current is induced through leg 455 by radiation of the higher frequency antenna element, and the larger sized antenna element 400 operating at a lower frequency does not affect the radiation of the smaller antenna element operating at a higher frequency.
(37) The length of the stubs 450 and 460 can be chosen at time of manufacture based on the frequency of the antenna element from which radiation is being received. The total length for current traveling from the tip of one stub to the tip of the other stub can be about one half the wavelength of the frequency at which the open circuit is to be created (e.g., about three centimeters total travel length to create an open circuit for a 5.0 GHz signal). For an antenna leg with two stubs, each stub can be a little less than half of the corresponding wavelength (providing for most of the length in the stubs and a small part of the length for traveling between the stubs along a top surface portion).
(38) Extending downward from near the center of the top surface 405, 410, 415, 420 are impedance matching elements 425, 430 and 435. Impedance matching elements 425, 430, 435 as illustrated in
(39) Impedance matching elements 425-435 extend downward towards a ground plane within circuit board 300 and form a capacitance between the impedance matching element and the ground plane. By forming a capacitance with the ground plane of the circuit board 300, the impedance matching elements achieve impedance matching at a desired frequency of the antenna element. To achieve impedance matching, the length of the impedance matching element and the distance between the circuit board ground plane and the closest edge of the downward positioned impedance matching element can be selected based on the operating frequency of the antenna element. For example, when an antenna element 400 is configured to radiate at about 2.4 GHz, each impedance matching element may be about 8 millimeters long and positioned such that the edge closest to the circuit board is about 2-6 millimeters (e.g., about 3.6 millimeters) from a ground plane within the circuit board.
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(41) The mountable antenna element 400 of
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(45) Reflector 700 can be constructed as an object formed from a single piece of material, such as tin, similar to the construction of antenna element 400. The reflector 700 can be symmetrical except for the pins 715 and the plate 720. Hence, the material for reflector 700 can be built as a flat and approximately T shaped unit with a center portion with arms extending out to either side of the center portion. The flat element can then be bent, for example, down the center of the base such that each arm is of approximately equal size and extends from the other arm at a ninety-degree angle.
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(49) The antenna element legs can be used to couple the antenna element to circuit board 300 (
(50) Extending downward from near the center of the top surface are impedance matching elements 925 and 930. A third impedance matching element is positioned opposite to impedance matching element 930 but not visible in the view of
(51) Impedance matching elements 925-930 extend downward from the top surface toward a ground plane within circuit board 300 and form a capacitance between the impedance matching element and the ground plane. The impedance matching elements achieve impedance matching at a desired frequency based on the length of the impedance matching element and the distance between the circuit board 300 ground plane and the closest edge of the downward positioned impedance matching element based. For example, when an antenna element 900 is configured to radiate at about 5.0 GHz, each impedance matching element may be about 5 millimeters long and positioned such that the edge closest to the circuit board is between 2-6 millimeters (e.g., about 2.8 millimeters) from a ground plane within the circuit board.
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(53) The dimensions of the mountable antenna element 900 can be smaller than those for mountable antenna element 400. When the mountable antenna element 900 is constructed to operate at about 5.0 GHz, the width and length of the mountable antenna element top surface can be about 0.700 inches long. The width of the gap between top surface portions 905 and 920 is 0.106 inches at the inner most point and 0.290 at the outermost point. The width of the gap between top surface portions 915 and 920 is about 0.070 inches, with the gap width between a impedance matching element and a top surface portion (e.g., impedance matching element 930 and top surface portion 915) is about 0.020 inches.
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(55) Antenna element 900 can be constructed as an object from a single piece of material, for example tin material. The mountable antenna element 900 can be formed from the single piece of material by manipulating portions of the material. In particular, antenna element impedance matching elements 925, 930 and 1010 can be bent downward, for example to a position perpendicular to top surface portions 905, 910, 915 and 920, and legs 935, 940, 945, and 950 can be bent downward along the same direction as the impedance matching elements. RF feed element 1005 can also be positioned in a downward direction with respect to the antenna element top surface, and the edge of RF feed element 1005 and leg 470 can be bent to form a coupling plate to be coupled to circuit board 300.
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(57) Base 1220 includes a mounting plate 1225. Mounting plate 1225 can be used to couple reflector 1200 to circuit board 300 via solder. In addition to mounting plate 1225, pins 1215 can also be soldered to area 320. Once the pins 1230 are inserted into holes 330 and coupling plate 1225 is in contact with a mounting pad, the reflector 1200 can stand upright without additional support, making installation of the reflectors easer than typical reflectors which do not have mounting pins 1230 and a mounting plate 1225.
(58) Reflector 1200 can be constructed as an object from a single piece of material, such as a piece of tin. The reflector 1200 can be symmetrical except for the pins 1230 and the plate 1225. Hence, the material for reflector 1200 can be built as a flat and approximately T shaped unit. The flat element can then be bent down the center such that each arm is of approximately equal size and extends from the other arm at a ninety-degree angle.
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(60) Though a finite number of mountable antenna elements are described herein, other variations of single piece construction mountable antenna elements are considered within the scope of the present technology. For example, an antenna element 400 generally has an outline of a generally square shape with extruding legs and stubs as illustrated in
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(62) The embodiments disclosed herein are illustrative. Various modifications or adaptations of the structures and methods described herein may become apparent to those skilled in the art. Such modifications, adaptations, and/or variations that rely upon the teachings of the present disclosure and through which these teachings have advanced the art are considered to be within the spirit and scope of the present invention. Hence, the descriptions and drawings herein should be limited by reference to the specific limitations set forth in the claims appended hereto.