Patent Application
20170149121
This application generally relates to wireless microphones, and more specifically, to antennas included in wireless microphones.
Wireless microphones are used to transmit sound to an amplifier or recording device without need of a physical cable. They are used for many functions, including, for example, enabling broadcasters and other video programming networks to perform electronic news gathering (ENG) activities at locations in the field and the broadcasting of live sports events. Wireless microphones are also used in theaters and music venues, film studios, conventions, corporate events, houses of worship, major sports leagues, and schools.
Typically, wireless microphone systems include a microphone that is, for example, a handheld unit, a body-worn device, or an in-ear monitor; a transmitter (e.g., either built into the handheld microphone or in a separate “body pack” device) comprising one or more antennas; and a remote receiver comprising one or more antennas for communicating with the transmitter. The antennas included in the microphone transmitter and receiver can be designed to operate in certain spectrum band(s), and may be designed to cover either a discrete set of frequencies within the spectrum band or an entire range of frequencies in the band. The spectrum band in which the microphone operates can determine which technical rules and/or government regulations apply to that microphone system. For example, the Federal Communications Commission (FCC) allows the use of wireless microphones on a licensed and unlicensed basis, depending on the spectrum band.
Most wireless microphones that operate today use spectrum within the “Ultra High Frequency” (UHF) bands that are currently designated for television (TV) (e.g., TV channels 2 to 51, except channel 37). Currently, wireless microphone users need a license from the FCC in order to operate in the UHF/TV bands (e.g., 470-698 MHz). However, the amount of spectrum in the TV bands available for wireless microphones is set to decrease once the FCC conducts the Broadcast Television Incentive Auction. This Auction will repurpose a portion of the TV band spectrum—the 600 MHz—for new wireless services, making this band no longer available for wireless microphone use. Wireless microphones can also be designed for operation in the currently licensed “Very High Frequency” (VHF) bands, which cover the 30-300 MHz range.
An increasing number of wireless microphones are being developed for operation in other spectrum bands on an unlicensed basis, including, for example, the 902-928 MHz band, the 1920-1930 MHz band, and the 2.4 GHz band (also known as the “ZigBee” band). However, given the vast difference in frequency between, for example, the UHF/TV bands and the ZigBee band, wireless microphone systems that are specifically designed for one of these two spectrums typically cannot be repurposed for the other spectrum without replacing the existing antenna(s).
Moreover, antenna design considerations can limit the number of antennas that are included within a single device (e.g., due to a lack of available space), while aesthetic design considerations can restrict the type of antennas that can be used. For example, whip antennas are traditionally good performers and by virtue of its external design, take up very little internal device space. However, these antennas can be expensive, distracting (for example, during a performance), and aesthetically unappealing, especially when they are long in length. As another example, handheld microphones typically include a reduced-size antenna that is integrated into the microphone housing to keep the overall package size small and comfortable to use. However, this limitation in antenna size/space makes it difficult for the handheld microphone to provide sufficient radiated efficiency.
More specifically, existing solutions for reduced-sized, broadband antennas include placement of a helical antenna within a housing of the handheld microphone, for example, as shown and described in U.S. Pat. Nos. 7,301,506 and 8,576,131, both of which are incorporated herein by reference in their entirety. In both cases, the helical antenna assembly includes an antenna tape wrapped around a dielectric core to form a single or double helix structure and the pitch, width, and/or length of the antenna tape is adjusted to obtain desired electrical characteristics. However, these existing antenna solutions are ineffective for use in broadband and multiband antenna operations.
Accordingly, there is a need for a wireless microphone system that can adapt to changes in spectrum availability, but still provide consistent, high quality, broadband performance with a low-cost, aesthetically-pleasing design.
The invention is intended to solve the above-noted problems by providing, among other things, (1) a wireless handheld microphone configured to operate in, for example, currently licensed bands (e.g., UHF/VHF), as well as currently unlicensed spectrum (e.g., 1.8 GHz/2.4 GHz/5.7 GHz), (2) a dual-band helical antenna integrated into a base of the wireless handheld microphone, and (3) a method of manufacturing a helical antenna assembly for the wireless handheld microphone with improved antenna performance.
For example, embodiments include an antenna assembly for a wireless microphone, the antenna assembly comprising a helical antenna including a feed point, and at least one contact pin coupling the feed point to the wireless microphone, wherein the helical antenna is configured for operation in a first frequency band and a second frequency band.
Example embodiments also include a wireless microphone comprising a main body having a top end and a bottom end and an antenna assembly coupled to the bottom end of the main body, wherein 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.
Another example embodiment includes a method of manufacturing an antenna assembly for a wireless microphone, the method comprising forming a core unit with a hollow body and a closed bottom end using a first manufacturing process, coupling a feed end of an antenna element to the core unit, wrapping an antenna element around the core unit to form a helical structure with a free end of the antenna element positioned adjacent to the bottom end of the core unit, and forming an overmold around the antenna element and the core unit using a second manufacturing process.
These and other embodiments, and various permutations and aspects, will become apparent and be more fully understood from the following detailed description and accompanying drawings, which set forth illustrative embodiments that are indicative of the various ways in which the principles of the invention may be employed.
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.
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.
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.
As shown in
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
Referring additionally to
Referring further to
Referring additionally to
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 116. For example, as shown in
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.
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
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
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
For example,
Referring now to
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).
In
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.
Referring now to
Referring additionally to
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.
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
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
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
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
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.
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.
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.
