Patent Grant
7859469
The present invention relates in general to wireless devices. More specifically, the present invention relates to a combined and compact battery holder and antenna support structure for wireless devices.
The demand for more power efficient and lightweight wireless devices, such as cellular telephones, wireless headsets, and other wireless devices, has required engineers to devise new ways of reducing the size, compactness and integration of the devices' components. Significant strides have been made in reducing the size and compactness of circuit components (e.g., resistors, capacitors, transistors) using integrated circuit technology. However, not all components can be easily formed into an integrated circuit. For example, the antenna and battery, both of which are essential components of any mobile wireless device, are not typically formed as part of an integrated circuit. The power needed to power a wireless device's components is simply too large to allow the battery to be formed at a size that could be practically formed in an integrated circuit.
Antennas are also not typically formed as part of an integrated circuit. An antenna's dimensions and proximity to other conductors affects radiation patterns and efficiency, and the larger the antenna is the better. Furthermore, the high-frequency energy that is generated by the antenna can interfere with other electronics. For these reasons an antenna is usually kept as far away as possible from any integrated circuits, and the antenna is not, therefore, typically formed as part of an integrated circuit.
Because the battery and antenna cannot be easily formed in an integrated circuit, they are typically mounted on a printed circuit board (PCB), along with other electrical components of the wireless device. One type of antenna that is commonly used in such applications is the inverted “F” antenna (IFA).
The length L of the horizontal arm 108 and the height h of the horizontal arm 108 above the ground plane 104 determine the bandwidth of the IFA 100. The resonant frequency of the IFA 100 depends on how well the height h of the horizontal arm 108 above the ground plane is controlled. If the height h is not consistently controlled along the entire length L of the arm 108, the resonant frequency of the IFA 100 is shifted from, or tends to drift from, its desired value. A height h that is not well controlled also adversely affects the impedance matching of the antenna to the PCB and, consequently, results in degraded reception and/or transmission capabilities. Accordingly, it is important that the height h of the horizontal arm 108 of the IFA 100 be well controlled over its entire length L.
In addition to controlling the height h of the horizontal arm 108 of an IFA 100, prior art approaches have focused on isolating the antenna, as best as possible, from conductive objects on the PCB. Conductive objects on the PCB, particularly those which extend substantially above the PCB surface can have the deleterious effect of detuning and/or degrading the radiation pattern of the IFA 100. The battery that is used to power the wireless device is also typically mounted on the same PCB as is the antenna. Since the battery is typically housed in a conductive case, prior art approaches strive to maintain ample separation between the battery and the antenna.
An unfortunate consequence of separating the antenna from the battery is that it prevents the design from being scaled down to a more compact size. In some applications, some degree of compacting can be achieved by “meandering” the length L of the horizontal arm 108 of the IFA 100, or by using a “planar” arm IFA (i.e., PIFA) that has the same or similar effect as an elongated linear arm. However, these approaches are not available if there is no space available on the PCB to accommodate the meandering or planar arm. Even in applications where space is available, the degree to which the design can be compacted is limited by the perceived need to maintain a generous degree of separation between the antenna and battery.
It would be desirable, therefore, to have methods and apparatus which allow an antenna, battery and/or other components of a wireless device to be combined in a manner that allows an overall reduction in size of the wireless device.
A combined, compact battery holder and antenna apparatus is disclosed. An exemplary combined, compact battery holder and antenna apparatus includes a dielectric battery holder and a conductive antenna element that is supported by the dielectric battery holder. When mounted on a printed circuit board (PCB), the dielectric battery holder maintains a radiating arm of the conductive antenna element at a constant height above a ground plane on the PCB.
According to one aspect of the invention, the dielectric battery holder has a cylindrically shaped bore, which is adapted to hold a coin-shaped type battery. The radiating arm of the conductive antenna element is formed at least partially around an outer surface of the coin-shaped type battery, and in a manner that maintains a constant spacing between the radiating arm and the outer circumference of the battery.
The systems and apparatus of the present invention offer a number of benefits and advantages over prior art approaches. For example, forming the radiating arm of the antenna element around the battery, and using the dielectric structure of the apparatus to both hold the battery and to support the antenna element allow a more compact design to be realized. Combining the battery holder and antenna support functions into a single component also reduces the number of parts needed in the assembly and, therefore, reduces overall costs of production.
The compact, combined battery holder and antenna apparatuses of the present invention may be beneficially adapted and configured for use in a variety of electronic devices including, for example, wireless headsets and headphones, wireless earbuds, hearing aid devices, cellular communications devices, personal digital assistants (PDAs), hand-held and lap-top computers configured with wireless network interface cards (NICs) or wireless modems, and satellite communications devices such as global positioning systems (GPSs). When adapted for use in such devices, the combined battery holder and antenna apparatuses may be further configured to operate according to any one of various types of wireless technologies or wireless technology standards such as, for example, Bluetooth, Wi-Fi (i.e., 802.11); WiMAX (802.16), and cellular technologies.
Other features and advantages of the present invention will be understood upon reading and understanding the detailed description of the preferred exemplary embodiments, found herein below, in conjunction with reference to the drawings, a brief description of which are provided below.
Those of ordinary skill in the art will realize that the following detailed description of the present invention is illustrative only and is not intended to be in any way limiting. Other embodiments of the present invention will readily suggest themselves to such skilled persons having the benefit of this disclosure. Reference will now be made in detail to implementations of the present invention as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts.
Referring to
As best illustrated in the unwrapped side view of
As shown in
According to an embodiment of the invention, the dielectric combined antenna support and battery holder structure 204 is cylindrically-shaped with a hole formed through its center. The hole is adapted to receive a coin-type battery 214 having a conductive casing. When the coin-type battery 214 is disposed within the hole, the conductive casing acts as a vertical equipotential plane. While this and other exemplary embodiment of the invention described herein are shown and described as being adapted to receive a coin-shaped battery 214, those of ordinary skill in the art will readily appreciate and understand that the dielectric combined antenna support and battery holder structure 204 may be easily modified to accommodate batteries of other shapes, e.g., square, rectangular, etc.
Collectively, the F-shaped electrically conductive structure 202, dielectric combined antenna support and battery holder structure 204, horizontal ground plane 206 and conductive casing of the coin battery 214 form an inverted-F antenna (IFA). The dielectric support/holder structure 204 functions to hold the coin battery, provide a support for at least a portion of the length L of the horizontal arm, and separate the horizontal arm 210 at a controlled distance from the outer circumference of the coin battery 214. When the coin battery 214 is secured in the dielectric support/holder structure 204, the conductive casing of the coin battery 214 is in electrical contact with the horizontal ground plane 206, and acts as a vertical ground plane with respect to the F-shaped electrically conductive structure 202. As will be readily appreciated by those of ordinary skill in the art the terms “horizontal” and “vertical” are used for convenience of expression only. Although the horizontal and vertical ground planes are perpendicular to each other, they do not have to be oriented with respect to the horizon. Moreover, although the “horizontal” and “vertical” ground planes are described in this exemplary embodiment as being perpendicular, in alternative embodiments the ground planes need not be perpendicular.
Combining the antenna elements, antenna support structure, battery and battery holder into a single compact unit provides a number of benefits over prior art approaches. First, since the antenna support structure and battery holder are integrated into single structure 204, and the F-shaped IFA structure is forced to follow the contours of the support/holder 204, the combined battery holder and antenna apparatus 200 occupies significantly less PCB area than do prior art approaches. Second, the controlled spacing between the F-shaped electrically conductive structure 202 and the horizontal ground plane 206 helps to maintain the resonant frequency of the antenna at a stable and constant value. Third, combining the antenna elements, antenna support structure, battery and battery holder into a single compact unit allows a smaller PCB to be used, compared to the size of the PCB used to implement prior art approaches. Finally, the vertical ground plane provided by the conductive battery housing and the F-shaped electrically conductive structure 202 work together to direct RF radiation around the circumference of the battery 414, rather than being blocked by the presence of the battery.
While the combined battery holder and antenna apparatus 200 in
Although the vertical ground plane has been described as being provided by the conductive housing of a battery, the vertical ground plane can be formed by a variety of structures.
As best illustrated in
Although in
The wireless device 500 in
Although the present invention has been described with reference to specific embodiments thereof, these embodiments are merely illustrative, and not restrictive, of the present invention. Various other modifications or changes to the specifically disclosed exemplary embodiments will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 5963177 | Tuttle et al. | Oct 1999 | A |
| 6067056 | Lake | May 2000 | A |
| 6424301 | Johnson et al. | Jul 2002 | B1 |
