Patent Publication Number: US-2023155274-A1

Title: Secondary antenna for wireless microphone

Description:
CROSS-REFERENCE 
     This application is a continuation of U.S. patent application Ser. No. 16/298,702, filed on Mar. 11, 2019, which is a continuation of U.S. patent application Ser. No. 15/187,063, filed on Jun. 20, 2016. The contents of these applications are incorporated by reference herein in their entireties. 
    
    
     TECHNICAL FIELD 
     This application generally relates to antennas included in wireless handheld microphones, and more specifically, to secondary antennas included in wireless handheld microphones. 
     BACKGROUND 
     Wireless microphones are used to transmit sound to an amplifier or recording device without the need for 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 for transmitting audio signals captured by the microphone; and a remote receiver comprising one or more antennas for receiving the audio signals from 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 system 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 microphone systems 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 microphone systems 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 microphone systems 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 (i.e. the 1.9 GHz or “DECT” band; also included within the 1.8 GHz band) and the 2.4-2.483 GHz band (i.e. “ZigBee” or IEEE 802.15.4; referred to herein as the “2.4 GHz 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. Moreover, handheld microphones with metal housings typically have very limited locations available for placement of an antenna, such as, for example, the very bottom of the microphone body. As a result, adding an additional antenna to such microphones can be difficult, if not impossible. 
     Accordingly, there is a need for a wireless microphone that can adapt to changes in spectrum availability, but still provide consistent, high quality, broadband performance with a low-cost, aesthetically-pleasing design. 
     SUMMARY 
     The invention is intended to solve the above-noted problems by providing, among other things, (1) a wireless handheld microphone comprising a secondary antenna configured to operate in high frequency bands (e.g., 1.5 GHz, 1.8 GHz, 2.4 GHz, 5.7 GHz, 6.9 GHz, or 7.1 GHz), and (2) placement of an antenna within the conductive body of a wireless handheld microphone. 
     Example embodiments include a wireless microphone comprising an elongated main body configured for handheld operation of the microphone; a display bezel area included in the main body; a first antenna positioned at a bottom end of the main body; and a second antenna integrated into the display bezel area. 
     Embodiments also include a wireless handheld microphone comprising a main body having a conductive housing and a tubular shape configured for handheld operation of the microphone; an opening included on a side surface of the conductive housing; a non-conductive cover coupled to the conductive housing and configured to cover the opening; and an antenna positioned adjacent to the non-conductive cover. 
     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. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side perspective view of an example wireless handheld microphone, in accordance with certain embodiments. 
         FIG.  2    is a close-up front view of an example display bezel area of the wireless handheld microphone of  FIG.  1   , in accordance with certain embodiments. 
         FIG.  3    is a top perspective view of an example electronics housing comprising an example antenna and located within the display bezel area of  FIG.  2   , in accordance with certain embodiments. 
         FIG.  4    is a cross-sectional view of the electronics housing shown in  FIG.  3   , in accordance with certain embodiments. 
         FIG.  5    is a cross-sectional view of a first example antenna feed structure for the antenna shown in  FIG.  3   , in accordance with certain embodiments. 
         FIG.  6    is a cross-sectional view of a second example antenna feed structure for the antenna element shown in  FIG.  3   , in accordance with certain embodiments. 
         FIG.  7    is a cross-sectional view of a third example antenna feed structure for the antenna element shown in  FIG.  3   , in accordance with certain embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     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. 
       FIG.  1    illustrates an example wireless handheld microphone  100 , in accordance with embodiments. The wireless microphone  100  comprises a main body  101  extending between a top end  102  and an opposing bottom end  103  of the main body  101 . As shown, the main body  101  forms an elongated, tubular handle for facilitating handheld usage of the microphone  100 . In embodiments, the wireless microphone  100  also comprises a display screen  104  (such as, for example, a liquid crystal display (LCD) or other suitable display) included in a display bezel area  106  of the main body  101 . As will be appreciated, the wireless microphone  100  may also include a microphone head (not shown) coupled to the top end  102  of the main body  101 . The microphone head typically includes a transducer element for receiving sound input, such as, for example, a dynamic, condenser, ribbon, or any other type of transducer element. The microphone head may also include, for example, a microphone grille, a microphone cover, and/or other components for covering the transducer. 
     Referring additionally to  FIG.  2   , the wireless microphone  100  further includes a primary antenna assembly  108  coupled to the bottom end  103  of the main body  101 , as shown in  FIG.  1   , and a secondary antenna  110  embedded into the display bezel area  106 , as shown in  FIG.  2   , in accordance with embodiments. As shown in  FIG.  1   , the main body  101  spans a distance L between the secondary antenna  110  and the primary antenna assembly  108 , and extends around and beyond the display bezel area  106  towards the top end  102 . In embodiments, the secondary antenna  110  can be formed from metal or other conductive material using any suitable technique, including, for example, laser direct structuring (LDS), metal forming, foiling, or selective plating. In some embodiments, the antenna structure  110  is printed onto an underlying plastic support piece (see, e.g., antenna support  118  in  FIG.  3   ) using the LDS technique. 
     In embodiments, the main body  101  can be made primarily of metal or other conductive material and can be configured to form an enclosure for housing various components of the microphone  100 . In addition, the main body  101  can include an opening or gap within a side surface of the metal enclosure (such as, e.g., opening  122  shown in  FIG.  2   ) and a non-conductive outer cover coupled to the main body  101  for covering this opening (such as, e.g., outer cover  120  shown in  FIG.  2   ). In embodiments, this covered opening forms a non-conductive surface on the otherwise conductive main body  101  and can be configured to provide access to, and/or enable operation of, one or more electronic components within the microphone  100 . For example, in the illustrated embodiment, the display bezel area  106  can be positioned within, and/or accessible through, the non-conductive, covered opening of the main body  101 . In other embodiments, the non-conductive opening of the main body  101  can provide access to additional, or alternative, electronic devices, such as, for example, a user interface (not shown) comprising one or more input devices for controlling operation of the microphone  100 . In some embodiments, the non-conductive opening can be included in the main body  101  specifically for enabling, and/or creating a space for, operation of one or more antennas of the wireless microphone  100 . Also, in various embodiments, the non-conductive opening can be positioned in the same or different locations of the main body  101  as compared to that shown in  FIGS.  1  and  2    and described herein. Thus, while the embodiments described herein are directed to placement of an antenna within the display bezel opening of the main body  101 , it should be appreciated that the same techniques can be used for placement of an antenna within any type of non-conductive opening within the main body  101 . 
       FIG.  2    depicts a close-up front view of the display bezel area  106  and various electronic components included therein, such as the display screen  104  and the secondary antenna  110 , in accordance with embodiments. The display screen  104  (also referred to herein as “LCD display”) can be configured to present a user interface for interacting with the wireless microphone  100  and/or displaying one or more settings associated with operation of the microphone  100 . In some cases, the wireless microphone  100  includes one or more input devices (not shown) (e.g., control buttons and/or switches, touch screen, etc.) disposed on the main body  101  and/or in the display bezel area  106  to enable user control of the microphone settings. 
     Referring additionally to  FIG.  3   , shown is a top perspective view of an example electronics assembly  112  included in the display bezel area  106  of the wireless microphone  100 , in accordance with embodiments. As shown, the electronics assembly  112  supports the LCD display  104  as well as other electronic components of the wireless microphone  100 . For example, the electronics assembly  112  may include an infrared device  113  for implementing short-range operations of the wireless microphone  100 . The electronics assembly  112  can further include a printed circuit board (PCB)  114  comprising circuitry components for enable operation of the secondary antenna  110 , the LCD display  104 , and/or the infrared device  113 . In embodiments, a feed point of the secondary antenna  110  can be coupled to the PCB  114  included in the electronics assembly  112 . The electronics assembly  112  may also include a flex PCB  115  coupled to the PCB  114  to convey an RF feed or other wireless signal to the feed point of the secondary antenna  110  for wireless transmission. In some embodiments, one or more circuitry components can be coupled between the secondary antenna  110  and the PCB  114  to provide appropriate impedance matching for the antenna  110 , as described in more detail with respect to  FIGS.  5 - 7   . 
     As also shown in  FIG.  3   , the electronics assembly  112  further includes a bracket  116  that surrounds and supports the LCD display  104  and can be made of metal or other conductive material. In embodiments, the electronic assembly  112  can also include a plurality of grounding tabs  117  that are configured to contact an interior of the main body  101  to ground the bracket  116  to the metal housing of the main body  101 . In such cases, the metal housing of the main body  101  can serve as a grounding plane for the secondary antenna  110  and/or the primary antenna assembly  108 , and can isolate the antennas from conducted and/or radiated RF interference from audio and power source circuitry included in the wireless microphone  100 . 
     Referring additionally to  FIG.  4   , shown is a cross-sectional view of the display bezel area  106  to illustrate an example configuration for completely integrating the secondary antenna  110  into the display bezel area  106  of the wireless microphone  100 , in accordance with embodiments. In the illustrated embodiment of  FIGS.  3  and  4   , the secondary antenna  110  is disposed on an antenna support  118  that is configured to position the antenna  110  against an underside of a non-conductive outer cover  120  for the display bezel area  106 . For example, the antenna support  118  (also referred to herein as a “support structure”) can be configured to elevate the antenna  110  above the display bezel area  106  and structurally support the antenna  110  against the outer cover  120 . As shown in  FIG.  4   , the secondary antenna  110  is positioned, or sandwiched, between the outer cover  120  and the antenna support  118 , so that the antenna  110  is adjacent to both two surfaces. In some embodiments, the antenna  110 , the outer cover  120 , and the antenna support  118  are joined together to form a cohesive unit into which the antenna  110  is embedded. In some embodiments, the antenna support  118  also serves as a non-conductive barrier between the antenna  110  and the electronic assembly  112  included in the display bezel area  106  to further minimize RF interference therebetween. 
     As shown in  FIG.  2   , the outer cover  120  can be configured to span across and cover a main body opening  122  in which the display bezel area  106  is positioned. The opening  122  (also referred to herein as a “non-conductive opening”) can be a gap in a side surface of the conductive main body  101  and can be configured to provide access to, and/or enable operation of, the electronics assembly  112  included in the display bezel area  106 , including, for example, the LCD display  104 . In some embodiments, the outer cover  120  can be made of a transparent or semi-transparent material, so that at least the LCD display  104  within the display bezel area  106  is visible and accessible on the surface of the wireless microphone  100 , as shown in  FIG.  2   . As shown in  FIGS.  2  and  4   , the outer cover  120  can be coupled to the main body  101 , for example, along a perimeter of the opening  122  and can be curved to match a curvature of an outer surface (i.e., the conductive enclosure) of the main body  101 , so that the outer cover  120  sits flush with, and/or forms a portion of, the outer surface of the main body  101 . In this manner, the outer cover  120  can be fully integrated with the outer surface of the main body  101 . 
     In embodiments, a shape of the secondary antenna  110  can be curved to match or conform to the curvature of the outer cover  120 , so that the antenna  110  is as close as possible to the outer surface of the wireless microphone  100  for optimizing antenna performance. The curved shape of the antenna  110  can also be configured to elevate the antenna  110  above the components of the electronic assembly  112 , such as, for example, the PCB  114 , to help minimize RF interference therewith. In the illustrated embodiment, the antenna support  118  also has a curved shape that matches or conforms to the shape of the outer cover  120  and/or the antenna  110 , to help position the antenna  110  flush against the outer cover  120 . In other embodiments, the secondary antenna  110  can be attached directly to the outer cover  120 . For example, the antenna  110  can be formed onto the underside of the outer cover  120  using LDS or metal plating techniques (not shown). In such cases, the antenna  110  may be integrated into the display bezel area  106  and placed adjacent to the outer cover  120  without using the antenna support  118 . 
     In embodiments, the secondary antenna  110  can have a physically shorter length due to the configuration of the display bezel area  106 . For example, the overall size and shape of the secondary antenna  110  can be limited, at least in part, by the space available within the display bezel area  106 . In particular, the antenna  110  must be small enough to fit within an opening  122  for placement of the display bezel area  106  into the main body  101 . The shape and size of the antenna  110  can also be configured to avoid contact with, or maintain sufficient distance from, the metal housing of the main body  101  and the conductive or electronic components in the display bezel area  106 , as described in more detail below. To compensate for the shorter antenna length, the outer cover  120  and/or the antenna support  118  can be made from dielectric materials configured to provide additional electrical properties for extending an electrical length of the secondary antenna  110 . In some embodiments, the outer cover  120  and/or the antenna support  118  can be made from dielectrically-loaded plastics that are specifically configured to enable wireless operation of the secondary antenna  110  within a desired frequency band (e.g., 1.5 GHz, 1.8 GHz, 2.4 GHz, 5.7 GHz, 6.9 GHz, 7.1 GHz, etc.). 
     The exact size and shape of the secondary antenna  110  can also be configured to avoid contact and/or RF interference with the LCD display  104  and other electronic components included in the display bezel area  106 , such as, for example, the infrared device  113  and the printed circuit board  114 , as well as other nearby conductive components, such as, for example, the conductive housing of the main body  101  and the metal bracket  116 . For example, the antenna support  118  can be configured to elevate the antenna  110  by a distance that is sufficient to avoid RF interference with the conductive and/or electronic components located there under. As another example, the secondary antenna  110  can be positioned between the LCD display  104  and the infrared device  113  and can be shaped to avoid overlap with, and maintain an electrically-significant distance from, either device. In the illustrated embodiment of  FIG.  2   , for example, the secondary antenna  110  includes an elongated portion  110   a  with a width and length configured to fit within the rectangular space available between the LCD display  104  and the infrared device  113 . In addition, the secondary antenna  110  further includes a second portion  110   b  with a length and width configured to fit within the square-like space available next to the infrared device  113 . 
     The exact shape and configuration of the secondary antenna  110  can also depend on the desired operating bands for the antenna  110  and the type of antenna being incorporated therein. According to embodiments, the secondary antenna  110  can be any suitable type of antenna, including, for example, a monopole antenna, a dipole antenna, an inverted-F antenna, a planar inverted-F antenna (PIFA), inverted L-antenna, dual inverted L-antenna, or hybrids of these antenna structures. Also in embodiments, the secondary antenna  110  can be configured to support any frequency band suitable for implementation of the antenna diversity feature of the wireless microphone  100 . For example, the secondary antenna  110  can be configured to operate within a frequency band that corresponds to one of the frequency bands supported by the primary antenna assembly  108 . In a preferred embodiment, both the primary antenna assembly  108  and the secondary antenna  110  are configured for wireless operation in the Zigbee or 2.4 GHz band. In other embodiments, both antennas can be configured for wireless operation in the 1.5 GHz, 1.8 GHz (which includes the 1.9 GHz or “DECT” band), 5.7 GHz, 6.9 GHz, or 7.1 GHz bands. As will be understood by one of ordinary skill in the art, each of these frequency bands covers or includes a range of frequencies surrounding the named frequency. 
     In some embodiments, the secondary antenna  110  can be further configured for dual-band operation in two or more high frequency bands, such as, for example, the UHF band, the 1.5 GHz, the 1.8 GHz band, the 2.4 GHz band, the 5.7 GHz band, the 6.9 GHz band, and/or the 7.1 GHz band. In such cases, the shape and/or type of the secondary antenna  110  can be modified to enable operation in the second frequency band. For example, the secondary antenna  110  may include an additional antenna structure (not shown) in addition to the antenna structure shown in  FIG.  3   . In some embodiments, such dual-band operation can be used for simultaneous transmission of audio and control data signals by the wireless microphone  100  to a remote receiver or transceiver. 
     According to embodiments, the primary antenna assembly  108  can include a primary antenna (not shown) configured for enabling wireless operation of the microphone  100  in conjunction with the secondary antenna  110 . In some embodiments, the primary antenna is capable of, or configured for, simultaneously transmitting audio data and control data to the remote receiver or transceiver, while the secondary antenna  110  is configured to transmit control data (e.g., control link signals) to the remote transceiver during diversity operation. In a preferred embodiment, the primary antenna is a dual-band antenna configured to operate in a first frequency band selected from currently licensed bands—such as, e.g., UHF bands (e.g., 470-950 MHz) and/or any of the VHF bands (e.g., 170-300 MHz)—for transmission of audio data, as well as in a second frequency band selected from currently unlicensed spectrum—such as, e.g., the 1.5 GHz band, the 1.8 GHz band, the 2.4 GHz band, the 5.7 GHz band, the 6.9 GHz band, the 7.1 GHz band, etc.—for transmission of control data. And the secondary antenna  110  is also configured to operate in the same second frequency band as the primary antenna for transmission of control data. 
     As an example, in embodiments, the primary antenna included in the primary antenna assembly  108  can be the dual-band antenna disclosed by U.S. patent application Ser. No. 14/947,933, the content of which is incorporated by reference herein in its entirety. U.S. patent application Ser. No. 14/947,933 discloses a wireless handheld microphone having an antenna assembly coupled to a bottom end of the microphone, wherein the antenna assembly includes a dual-band helical antenna wrapped around a core unit and covered by an outer shell that interfaces with the bottom end of the microphone, and wherein one embodiment of the helical antenna includes a first antenna structure configured for operation in a lower UHF band (e.g., 470-636 MHz) and a second antenna structure configured for operation in the Zigbee 2.4 GHz band. 
     In embodiments, the exact locations for placement of the antenna assembly  108  and the antenna  110  on the microphone  100  can be selected based on antenna placement feasibility, or the feasibility of antenna operation in a given location. For example, in the illustrated embodiment, the outer housing or enclosure of the main body  101  of the microphone  100  is made of metal or other conductive material and therefore, antenna placement may not be feasible within the main body  101 . On the other hand, the outer housings for the display bezel area  106  (e.g., the outer cover  120 ) and the primary antenna assembly  108  are made from plastic or other non-conductive material and therefore, antenna placement may be feasible in both of these locations. In other embodiments, the microphone  100  may include additional or alternative non-conductive openings in the main body  101  that similarly allow for antenna placement, such as, for example, an opening for receiving a user interface bezel or an opening specifically configured for antenna placement along the main body  101 . 
     In addition to concerns for the feasibility of antenna operation, the locations of the secondary antenna  110  and the primary antenna assembly  108  can be selected to maximize a physical separation between the respective antennas, thereby enabling spatial diversity operation of the antennas and minimizing mutual coupling between the antennas. For example, as shown in  FIG.  1   , the primary antenna assembly  108  is coupled to the bottom end  103  of the main body  101 , while the secondary antenna  110  is included in the display bezel area  106 , which is positioned near the top end  102  of the main body  101 . As a result, the two antennas are separated from each other by a main length of the main body  101 , or the distance L that spans across a substantial portion of the main body  101 , as shown in  FIG.  1   . In embodiments, the distance L may be sufficient to enable the primary antenna assembly  108  and the secondary antenna  110  to operate as spatial diversity antennas for the wireless microphone  100 . As will be appreciated, to provide spatial diversity operation at a given frequency, the antennas should be separated from each other by a distance that is significantly greater than a quarter-wavelength of that frequency. For example, in the case of 1.5 GHz operation, the wavelength is approximately 7.9 inches and therefore, the two antennas must be spaced apart by at least 2 inches in order to maximize diversity operation at this frequency. Accordingly, the distance L can be selected to ensure optimal diversity operation for the antennas  108  and  110 . 
     In addition to enabling spatial diversity, the physical separation between the secondary antenna  110  and the primary antenna assembly  108  can help minimize the probability of radio frequency (RF) link loss due to, for example, human body detuning or other antenna obstruction. As will be appreciated, antenna detuning can occur when an antenna element is placed in close proximity to metal or other conductive parts and/or placed on or near a human body. For example, placement of a user&#39;s hand over the display bezel area  106  or the bottom end  103  may cause the corresponding antenna to loss RF connection. In embodiments, the spatial separation between the antenna assembly  108  and the secondary antenna  110  can help mitigate the effects of antenna obstruction by lowering the probability that both antennas will experience RF link loss at the same time. For example, a human hand placed over the bottom end  103  may adversely affect RF operation of the primary antenna assembly  108  but not the secondary antenna  110 . In such cases, antenna operation may switch from the primary antenna assembly  108  to the secondary antenna  110  to provide better signal quality. Likewise, if the signal quality obtained by the secondary antenna  110  becomes degraded due to a nearby obstruction, antenna operation may switch from the antenna  110  to the primary antenna assembly  108 . 
     In embodiments, the wireless microphone  100  can further include a processor and/or other hardware (not shown) configured to implement antenna switching and/or selecting processes for enabling diversity operation of the antennas  108  and  110 . In addition, the wireless microphone  100  may include a transmitter, receiver, and/or transceiver (not shown) coupled to the processor, the primary antenna assembly  108 , and the secondary antenna  110  for supporting various wireless applications, including transmission and/or reception of radio frequency (RF) signals between the wireless microphone  100  and other devices within the microphone system (not shown), such as, for example, a remote receiver or transceiver. 
     According to embodiments, when operating in an antenna selection mode, the processor can be configured to monitor the signal quality of an RF link with a first antenna (e.g., the primary antenna assembly  108 ) by, for example, comparing the signal quality against a predetermined threshold. If the processor detects that the signal quality has dropped below the predetermined threshold, for example, due to obstruction of the first antenna, the processor can be configured to switch operation to a second antenna (e.g., the secondary antenna  110 ), for example, by establishing an RF link with the second antenna. In such cases, the second antenna can be configured to transmit audio data and/or control data to provide wireless coverage for the first antenna. In a preferred embodiment, the second antenna is configured to transmit control data over a given frequency band when the first antenna is obstructed or otherwise incapable of transmitting control data over that band (e.g., the Zigbee or 2.4 GHz band). 
     In some embodiments, the processor can be configured to operate in a switching diversity mode upon determining that the transceiver of the wireless microphone  100  is operating in a diversity mode. In such cases, due to the spatial diversity created through placement of the antennas  108  and  110  on opposite ends of the main body  101 , the processor can switch between the primary antenna  108  and the secondary antenna  110  to provide wireless operation within a given frequency band. In a preferred embodiment, both the secondary antenna  110  and the primary antenna  108  can be configured to transmit control data over the given frequency band (e.g., the Zigbee or 2.4 GHz band). 
       FIG.  5    illustrates an example antenna feed structure  200  for providing impedance matching for the secondary antenna  110 , in accordance with embodiments. As shown in  FIG.  5   , the antenna feed structure  200  includes a connection pin  201  configured to electrically couple the secondary antenna  110  to the printed circuit board  114  and provide an RF feed point for the antenna  110 . The connection pin  201  can be a pogo pin or any other suitable RF connector. In embodiments, the antenna feed structure  200  can be configured to use the location of the connection pin  201  to obtain transmission line matching. For example, in the illustrated embodiment, the antenna feed structure  200  includes a first extension  202  configured to directly connect the antenna  110  to the ground plane of the microphone  100  by extending a length of the second portion  110   b  of the secondary antenna  110  until a first end  204  of the antenna  110  contacts the metal housing of the main body  101 . The antenna feed structure  200  can also include a second extension  206  for extending a length of the elongated portion  110   a  of the secondary antenna  110 , so that a second end  208  of the antenna  110  extends further across the opening  122  of the display bezel area  106 , but still remains open or unattached. In such embodiments, the antenna  110  can be configured as a curved planar inverted-F antenna (PIFA) type, and the location of the connection pin  201  relative to the fixed end  204  and the open end  208 , as well as the direct ground connection formed by the first extension  202 , can provide appropriate impedance matching for the RF feed point of the antenna  110 . 
       FIG.  6    illustrates another example antenna feed configuration  300  for providing impedance matching for the secondary antenna  110 , in accordance with embodiments. As shown in  FIG.  6   , the antenna feed structure  300  includes a connection pin  301  similar to the connection pin  201  described above. However, in the antenna feed structure  300 , the second portion  110   b  for grounding the antenna  110  is removed. Instead, the connection pin  301  is directly coupled to the ground plane, or the main body  101 , by an inductor  302 , such as, for example, a high quality (Q) inductor or other RF coil. In such embodiments, the secondary antenna  110  can be configured as a modified curved PIFA type, and the inductor  302  can be configured to provide appropriate impedance matching for the RF feed point of the antenna  110 . For example, in some embodiments, the inductor  302  can include two inductors (not shown) connected in parallel in order to provide the appropriate inductance value required for impedance matching and to minimize signal losses. As shown in  FIG.  6   , the antenna feed structure  300  can also include an extension  306  for extending a length of the elongated portion  110 a of the secondary antenna  110 , so that a second end  308  of the antenna  110  extends further across the opening  122  while still remaining open or unattached. In some cases, the length of the extension  306  can be configured to compensate for removal of the second portion  110   b  from the antenna  110 . 
       FIG.  7    illustrates another example antenna feed configuration  400  for providing impedance matching for the secondary antenna  110 , in accordance with embodiments. As shown in  FIG.  7   , the antenna feed structure  400  includes a connection pin  401  similar to the connection pin  201  described above. Like the antenna feed configuration  300 , the antenna feed configuration  400  does not include the second portion  110   b  of the secondary antenna  110 . As illustrated, the antenna feed structure  400  includes an impedance matching network  402  coupled between the connection  401  and the PCB  114 . In embodiments, the matching network  402  can be a lumped component (LC) matching network comprising a plurality of inductors and capacitors that are configured to receive the RF signal before the signal is fed into the antenna  110 . In such embodiments, the secondary antenna  110  can be configured as a curved monopole antenna type, and the feed point to the connection pin  401  can serve as the starting point of the radiating portion of the antenna  110 . 
     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.