Helical antenna for wireless microphone and method for the same
11251519 · 2022-02-15
Assignee
Inventors
- Christopher Zachara (Lake Bluff, IL, US)
- Adem Celebi (Oak Park, IL, US)
- Gregory W. Bachman (Glen Ellyn, IL, US)
Cpc classification
H04R1/04
ELECTRICITY
H04R2420/07
ELECTRICITY
International classification
H04R1/04
ELECTRICITY
H01Q1/36
ELECTRICITY
Abstract
Embodiments include an antenna assembly for a wireless microphone, comprising a helical antenna including a feed point and at least one contact pin coupling the feed point to the wireless microphone. The helical antenna is configured for operation in first and second frequency bands. Embodiments also include a wireless microphone comprising a main body having top and bottom ends and an antenna assembly coupled to the bottom end. The antenna assembly comprises a helical antenna configured to transmit and receive wireless signals, an inner core configured to support the helical antenna on an outer surface of the inner core, and an outer shell formed over the inner core and the helical antenna. Embodiments further include a method of manufacturing an antenna assembly for a wireless microphone using a first manufacturing process to form a core unit of the antenna assembly and a second manufacturing process to form an overmold.
Claims
1. An antenna assembly for a wireless microphone, comprising: a helical antenna including a feed point, and a pair of contact pins coupling the feed point to the wireless microphone, each contact pin having a first end connected to the feed point, wherein the contact pins include a primary contact pin and a redundant contact pin, and extend out from the feed point substantially perpendicular to the helical antenna, the two pins configured to operate as a single pin for electrically connecting the helical antenna to the wireless microphone.
2. The antenna assembly of claim 1, wherein the helical antenna further comprises: a first antenna structure configured for operation in a first frequency band, and a second antenna structure configured for operation in a second frequency band, wherein the first and second antenna structures both extend from the feed point.
3. The antenna assembly of claim 2, wherein the contact pins extend out from the feed point at a preset angle relative to the first and second antenna structures.
4. The antenna assembly of claim 2, wherein the first antenna structure is longer in length than the second antenna structure.
5. The antenna assembly of claim 2, wherein the second antenna structure extends out from the feed point independently of the first antenna structure, such that a free end of the first antenna structure is spatially separated from a free end of the second antenna structure.
6. The antenna assembly of claim 2, wherein the second frequency band includes at least 2.4 Gigahertz (GHz) operating band.
7. The antenna assembly of claim 2, wherein the first frequency band includes at least one Ultra High Frequency (UHF) operating band.
8. The antenna assembly of claim 2, wherein the helical antenna is configured to simultaneously transmit and receive wireless signals in the first and second frequency bands.
9. A wireless microphone, comprising: a main microphone body having a top end and a bottom end; a printed circuit board (PCB); a connector coupled to the PCB; and an antenna assembly coupled to the bottom end of the main microphone body, the antenna assembly comprising: a helical antenna configured to transmit and receive wireless signals; a pair of contact pins comprising a primary contact pin and a redundant contact pin, each contact pin having a first end connected to a feed point of the helical antenna, wherein the two contact pins extend out from the feed point substantially perpendicular to the helical antenna and are configured to operate as a single pin for electrically connecting the helical antenna to the connector; an inner core supporting the helical antenna on an outer surface of the inner core; and an outer shell covering the inner core and the helical antenna.
10. The wireless microphone of claim 9, wherein the contact pins are coupled to the inner core and extend out from the inner core towards the main body.
11. The wireless microphone of claim 9, wherein the helical antenna comprises a first antenna structure with an elongated body wrapped around a main body of the inner core and a rounded end portion folded over a closed bottom end of the inner core.
12. The wireless microphone of claim 11, wherein the helical antenna further comprises a second antenna structure that is shorter in length than the first antenna structure, both antenna structures extending out from the feed point.
13. The wireless microphone of claim 12, wherein the second antenna structure extends out from the feed point independently of the first antenna structure, such that a free end of the first antenna structure is spatially separated from a free end of the second antenna structure.
14. The wireless microphone of claim 9, wherein the outer shell is attached to the inner core using an adhesive.
15. A method of manufacturing an antenna assembly for a wireless microphone, the method comprising: creating a core unit with a main body and a closed bottom end using a first manufacturing process; coupling a feed end of an antenna element to the core unit, the feed end being connected to each of a primary contact pin and a redundant contact pin, wherein the two contact pins extend out from the feed point substantially perpendicular to the antenna element and operate as a single pin for electrically connecting the antenna element to the wireless microphone; wrapping the antenna element around the core unit to form a helical structure with a first free end of the antenna element positioned adjacent to the bottom end of the core unit; and coupling an outer shell to the core unit to cover the antenna element using a second manufacturing process.
16. The method of claim 15, wherein coupling the feed end comprises inserting the contact pins into the core unit so that the contact pins extend out of the core unit and towards an open top end of the core unit.
17. The method of claim 15, wherein coupling the outer shell comprises adhering the outer shell to the core unit using an adhesive.
18. The method of claim 15, further comprising adhering the antenna element to the core unit using a plurality of alignment pins positioned on an outer surface of the core unit.
19. The method of claim 15, wherein the antenna element includes a first antenna structure comprising an elongated body extending from the feed end to the first free end, and a second antenna structure extending from the feed end to a second free end that is spatially separated from the first free end.
20. The method of claim 19, further comprising folding the first free end of the first antenna structure over the bottom end of the core unit.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DETAILED DESCRIPTION
(12) The description that follows describes, illustrates, and exemplifies one or more particular embodiments of the invention in accordance with its principles. This description is not provided to limit the invention to the embodiments described herein, but rather to explain and teach the principles of the invention in such a way as to enable one of ordinary skill in the art to understand these principles and, with that understanding, be able to apply them to practice not only the embodiments described herein, but also other embodiments that may come to mind in accordance with these principles. The scope of the invention is intended to cover all such embodiments that may fall within the scope of the appended claims, either literally or under the doctrine of equivalents.
(13) It should be noted that in the description and drawings, like or substantially similar elements may be labeled with the same reference numerals. However, sometimes these elements may be labeled with differing numbers, such as, for example, in cases where such labeling facilitates a more clear description. Additionally, the drawings set forth herein are not necessarily drawn to scale, and in some instances proportions may have been exaggerated to more clearly depict certain features. Such labeling and drawing practices do not necessarily implicate an underlying substantive purpose. As stated above, the specification is intended to be taken as a whole and interpreted in accordance with the principles of the invention as taught herein and understood to one of ordinary skill in the art.
(14) With respect to the exemplary systems, components and architecture described and illustrated herein, it should also be understood that the embodiments may be embodied by, or employed in, numerous configurations and components, including one or more systems, hardware, software, or firmware configurations or components, or any combination thereof, as understood by one of ordinary skill in the art. Accordingly, while the drawings illustrate exemplary systems including components for one or more of the embodiments contemplated herein, it should be understood that with respect to each embodiment, one or more components may not be present or necessary in the system.
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(16) As shown in
(17) The core unit 108, the helical antenna 106, and the outer shell 110 constitute an integrated helical antenna assembly 112 of the wireless microphone 100. As shown in
(18) Referring additionally to
(19) Referring further to
(20) Referring additionally to
(21) As illustrated, the contact plate 221 includes one or more contact pins 224 that extend out from, and perpendicular to, the antenna element 220. In embodiments, the one or more contact pins 224 are configured to electrically couple the feed point 222 of the antenna element 220 to the PCB 115 within the chassis 114. For example, as shown in
(22) According to embodiments, the antenna element 220 can be frequency-scalable in order to cover any desired operating band and can include multiple antenna structures coupled to a common feed location, or the feed point 222, in order to cover a plurality of different frequency bands. For example, the antenna element 220 can operate as a dual-band antenna that includes a first antenna structure 227 that is configured for wireless operation in a first frequency band and a second antenna structure 228 that is configured for wireless operation in a second frequency band. In embodiments, the first frequency band can include any of the UHF bands (e.g., 470-950 MHz), any of the VHF bands (e.g., 30-300 MHz), or any combination thereof, and the second frequency band can include the 902-928 MHz band, the 1920-1930 MHz band, the 1.8 GHz band, the 2.4 GHz band, the 5.7 GHz band, or any combination thereof. In a preferred embodiment, the first frequency band includes a lower UHF band (e.g., 470-636 MHz), and the second frequency band includes the Zigbee 2.4 GHz band.
(23) A length, width, angle, and configuration of the antenna structures 227, 228 can be selected in order to optimize antenna performance in the given frequency band(s) and provide a broadband antenna 200. For example, due to the inverse relationship between antenna length and frequency coverage, the first antenna structure 227, which covers lower operating bands, may be significantly longer than the second antenna structure 228, which covers higher operating bands. As shown in
(24) To keep an overall size of the antenna 200 at a minimum, the antenna element 220 can be configured to conform to the shape of the core unit 108 and cover a surface area of the core unit 108. For example, as shown in
(25) As will be appreciated, other antenna structures, shapes, sizes, lengths, and/or configurations may be utilized to form the antenna 200 depending on a desired frequency coverage and/or antenna performance standard, as well as the size, shape, and/or configuration of the core unit 108. For example, in some embodiments, the tab portion 227b may have a rectangular, square, polygonal, oval, or any other shape that can fit onto the bottom end 108b of the core unit 108. As another example, the second antenna structure 228 may have any other shape, including, for example, a rounded or triangular shape, so long as the structure 228 does not interfere with the first antenna structure 227. Further, while
(26) For example,
(27) Referring now to
(28) In embodiments, the antenna tape 229 can include two or more conductive strips 230 that are interconnected to neighboring strips 230 through the placement of one or more shorting pins 234 at predetermined locations on the substrate portion 232. The predetermined locations of the shorting pins 234 can be selected to provide optimal impedance matching for the antenna 200. For example, the shorting pins 234 can be positioned to provide an input impedance of about 50 ohms, so that the antenna 200 can be impedance matched to a 50 ohm reference impedance (e.g., transmission line) without the use of a lump component matching network. The use of multiple antenna strips 230 and multiple shorting pins 234 also enables multiple antenna modes to be excited at different frequencies, thereby resulting in a wider operational bandwidth and improved radiated efficiency for the antenna 200. Moreover, a length, width, and pitch value for each conductive strip 230 can be selected to optimize antenna performance and provide coverage of desired frequency band(s).
(29) In
(30) In the illustrated embodiment, the antenna tape 229 includes three conductive strips 230a, 230b, and 230c, with a first shorting pin 234a positioned between top strip 230a and middle strip 230b, and a second shorting pin 234b positioned between the middle strip 230b and bottom strip 230c. Other configurations and combinations for the conductive strips 230 and the shorting pins 234 are also contemplated, including a fewer or greater number of strips 230 and a fewer or greater number of pins 234, in accordance with the principles and techniques disclosed herein. For example, in one embodiment (not shown), the antenna tape 229 may include two conductive strips 230 with one shorting pin 234 positioned between the two strips 230.
(31) Referring now to
(32) Referring additionally to
(33) As shown, the method 300 can begin at step 302 by forming a hollow core unit, such as, for example, the core unit 108, using a first manufacturing process. For example, the core unit 108 can be formed during a first step of a multi-step injection molding process, such as, e.g., an inner core molding step. In embodiments, the core unit 108 is manufactured from a low-loss dielectric material, such as, for example, Thermoplastic Vulcanizate (TPV), Thermoplastic Urethane (TPU), or other suitable material. The mold used to construct the core unit 108 can be configured to minimize the dielectric loss in the helical antenna assembly 112, thereby improving the antenna efficiency and bandwidth of the antenna 200. For example, in embodiments, the core unit 108 may be designed to have a minimal amount of dielectric material by forming the core unit 108 as a generally tubular shell with a hollow center and an open top end 108c opposite the closed bottom end 108b. The walls of the core unit 108 can be configured to have a minimal thickness based on a minimum thickness required to maintain the structural integrity of the walls, and a minimum amount of dielectric material needed to tune the antenna 200. By reducing the total amount of dielectric material included in the core unit 108, the core unit 108 exhibits less dielectric loss, which translates into better radiation efficiency (e.g., as compared to a solid core unit made from the same dielectric material). The air inside the hollow core unit 108 improves radiated efficiency of the first and second antenna structures. Accordingly, the core unit 108 of the helical antenna assembly 112 can exhibit improved antenna efficiency without being dielectrically loaded.
(34) At step 304, the method 300 includes coupling a feed end of an antenna, such as, for example, the feed point 222 of the antenna 200, to the core unit. As shown in
(35) At step 306, the method 300 includes wrapping an antenna element of the antenna, such as, for example, the antenna element 220, around the core unit to form a helical structure, for example, as shown in
(36) In some embodiments, the method 300 further includes, at step 310, adhering the antenna element to an outer surface of the core unit using a plurality of pins positioned on the core unit. For example, as shown in
(37) At step 312, the method 300 includes forming an outer shell or overmold, such as, for example, the outer shell 110, around the antenna and core unit using a second manufacturing process. For example, the outer shell 110 can be formed during a second step of the multi-step injection molding process, such as, e.g., an over-shot molding step. In other cases, the outer shell 110 may be separately or independently formed and then coupled to the antenna and core unit using, for example, an adhesive or other form of attachment. As shown in
(38) Thus, a dual-band helical antenna assembly with greatly improved bandwidth and high radiated efficiency is provided, in accordance with the principles and techniques described herein. In embodiments, the helical antenna assembly includes a three-dimensional, conformal, multi-strip, helical antenna structure for providing the high radiated efficiency, which also renders the helical antenna assembly less susceptible to detuning caused by human loading. Moreover, the antenna includes two distinct antenna structures for operating effectively over at least two distinct frequency bands (e.g., the UHF bands and the 2.4 GHz band). The two antenna structures are coupled to one feed point and can provide simultaneous transmission and reception in the covered frequency bands. In addition, due at least in part to the structural design of the antennas included therein, the helical antenna assembly can provide 50 ohm input impedance without the use of a lump component matching network. Also, the helical antenna structure is disposed in an integrated antenna assembly that is manufactured using a multi-step molding process configured to minimize material dielectric losses in the antenna. For example, the multi-step molding process includes creating a hollow core shell for supporting the helical antenna using a minimal amount of dielectric material and creating a dielectric overmold for placement over the core and antenna combination.
(39) Any process descriptions or blocks in figures should be understood as representing modules, segments, or portions of code which include one or more executable instructions for implementing specific logical functions or steps in the process, and alternate implementations are included within the scope of the embodiments of the invention in which functions may be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved, as would be understood by those having ordinary skill in the art.
(40) This disclosure is intended to explain how to fashion and use various embodiments in accordance with the technology rather than to limit the true, intended, and fair scope and spirit thereof. The foregoing description is not intended to be exhaustive or to be limited to the precise forms disclosed. Modifications or variations are possible in light of the above teachings. The embodiment(s) were chosen and described to provide the best illustration of the principle of the described technology and its practical application, and to enable one of ordinary skill in the art to utilize the technology in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the embodiments as determined by the appended claims, as may be amended during the pendency of this application for patent, and all equivalents thereof, when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.