Antenna design in the body of a wearable device

A portable computing device includes an antenna within its housing structure for wireless connectivity, where an upper partition of the housing structure is used to construct an antenna plane, and a ground plane is incorporated into a lower partition of the housing structure. In some cases, the antenna is capable of maintaining wireless connectivity over a wide frequency band. Some embodiments include a device mount external to the upper partition and the lower partition of the housing structure that enables mounting the portable computing device to another entity, such as a user. In some cases, the device mount is external to the antenna used by the portable computing device, and does not include any portions of the antenna.

BACKGROUND

Over time, advancements in technology have produced smaller devices with increased functionality, such as wireless connectivity. As devices decrease in size, their portability increases. Thus, smaller devices with wireless connectivity allow users to easily move the devices from place to place while remaining in contact with a corresponding wireless network. However, these smaller forms can pose challenges for reliability when it comes to wireless connectivity. More particularly, the physical constraints of these smaller forms can affect how efficiently a corresponding antenna radiates wireless signals which, in turn, impacts the smaller devices' ability to maintain a wireless connection.

DETAILED DESCRIPTION

Turning to the drawings, wherein like reference numerals refer to like elements, techniques of the present disclosure are illustrated as being implemented in a suitable environment. The following description is based on embodiments of the claims and should not be taken as limiting the claims with regard to alternative embodiments that are not explicitly described herein.

Portable devices with wireless connectivity allow a user to access a wireless network, and any corresponding functionality associated with the wireless network, from a myriad of locations. In some cases, a user can wear or attach the portable device to their person, thus making the device easier to transport. As one example, a portable device with wireless connectivity can be configured as a wearable watch that mounts to a user via a wristband. These wearable devices provide additional reassurance to the user that the device, and the wireless access it provides, is always present and accessible. However, a portable device operating in this capacity (e.g., small enough to be portable and attached to a user) can have extra challenges associated with maintaining a wireless link. For instance, an antenna for such a device has the additional constraints of fitting into a device size that is acceptable to a user while still maintaining a radiation pattern with enough strength and shape to preserve a wireless link when worn by a user.

The embodiments described herein provide a portable system with wireless connectivity. A portable computing device includes an antenna within its housing structure for wireless connectivity, where an upper partition of the housing structure is used to construct an antenna plane, and a ground plane is incorporated into a lower partition of the housing structure. In some cases, the antenna is capable of maintaining wireless connectivity over a wide band of frequencies, such as a frequency band that ranges from 700 Megahertz (MHz) to 2700 MHz. Some embodiments include a device mount external to the housing structure that enables mounting the portable computing device to another entity, such as a user. In some embodiments, the device mount is external to the antenna used by the portable computing device, and does not include any portions of the antenna.

Consider now an example environment in which various embodiments can be employed.

Example Environment

FIG. 1illustrates an example operating environment100in accordance with one or more embodiments. Operating environment100includes a portable computing device102worn on the wrist of user104. In this example, portable computing device102takes the form of a wrist-wearable watch (e.g., wristwatch), but it is to be appreciated that portable computing device102can be implemented in any other suitable manner. Among other things, portable computing device102connects to wireless device106via wireless link108. Here, wireless device106and wireless link108generically represent any suitable device that portable computing device102can connect to using any suitable wireless signal and/or protocol. For example, wireless device106can be a cellular base station, a wireless access point, another portable computing device, a fixed computing device, and so forth. Similarly, wireless link108can be a Bluetooth™ wireless link, a cellular wireless link (General Packet Radio Service (GPRS), Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), Long-Term Evolution (LTE), Wideband Code Division Multiple Access (WCDMA), Mobile Worldwide Interoperability for Microwave Access (Mobile WiMAX), etc.), a wireless local area network link (WLAN or Wi-Fi), and so forth. In some embodiments, portable computing device102supports multiple different wireless links that span several different frequency bands. Thus, at times, wireless link108represents multiple wireless links.

Portable computing device102includes housing structure110, which generally represents a housing structure or chassis that encloses the various hardware and software components that make up the portable computing device. Housing structure110can be made of any suitable type and combinations of material, such as a metal, a polymer, a composite, a ceramic, etc. In some cases, an upper housing portion of the housing structure can be made of a first material, and a lower portion of the housing structure can be made of a second material. Housing structure110generally includes an antenna112, which is used to radiate and receive electromagnetic waves that enable portable computing device102to communicate to wireless device106over wireless link108. Antenna112can be configured to radiate and receive signals over any suitable frequency range, such as frequency range that generally covers an Ultra-Low band to a High Band frequency (e.g., 700-2700 MHz). Here, the term “generally” is used to indicate a frequency range over which antenna112radiates and receives frequencies successfully enough to recover information contained within the frequencies. This can include real-world deviations from these frequencies that allow for alternate frequencies that are not exactly these values. In some cases, the physical construction of antenna112uses part or all of housing structure110. For example, in at least one embodiment, antenna112uses housing structure110to form a Planar Inverted-F Antenna (PIFA), as further described below.

Portable computing device102includes wireless link component(s)114that generally represents hardware and/or software components configured to maintain a wireless link (e.g., wireless protocols, configure signals to send information over wireless link108via antenna112, decode signals to extract information received over wireless link108via antenna112, etc.) For example, wireless link component(s)114can include any combination of protocol stacks, receive paths, transmit paths, modulators, demodulators, an analog-to-digital converter (ADC), a digital-to-analog converter (DAC), and so forth. Wireless link component(s)114can be partially or fully enclosed in housing structure110.

Portable computing device102also includes processor(s)116. Processor(s)116can be configured as a single or multi-core processor capable of enabling various functionalities of the portable computing device. In some cases, processor(s)116includes a digital-signal processing subsystem for processing various signals/data that are captured or generated by wireless link component(s)114. Processor(s)116can be coupled with, and may implement functionalities of, any other components or modules of portable computing device102that are described herein.

Portable computing device102includes computer-readable media118, which stores device data120. Here, device data120represents various types of data stored on computer-readable media118, and ranges from executable code used to drive processor(s)116, to stored values. Thus, device data120can include an operating system, firmware, applications, contact information, and so forth.

Portable computing device102also includes device mount122. Device mount122represents a mechanism that enables a user to mount portable computing device102to their person or other object. In this example, device mount122takes on the form of a wristband. The wristband can be constructed of any suitable type of material, such as leather, nylon, silicon, etc. In some cases, a wristband can be constructed using a metal when the connection points between the wristband and other portions of the portable computing device are properly isolated (electrically) from one another. While device mount122is discussed in the form of a wristband, any other suitable mounting component can be used, such as an arm sleeve, a necklace or chain, a lanyard, a suction cup, a safety-pin fastener, a pin-and-cap mechanism, and so forth. For simplicity's sake, portable computing device102includes device mount122. However, in other embodiments, device mount122is considered as an external component relative to portable computing device102, and is sometimes optional. Alternately or additionally, device mount122is a removable component of portable computing device102, in that removing the device mount does not affect the operation of portable computing device102.

Generally, any of the functions described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), manual processing, or a combination of these implementations. The terms “module,” “functionality,” “component”, and “logic” as used herein generally represent software, firmware, hardware, or a combination thereof. In the case of a software implementation, the module, functionality, component, or logic represents program code that performs specified tasks when executed on or by a processor (e.g., one or more Central Processing Units (CPUs)). The program code can be stored in one or more computer readable memory devices.

Having described an example operating environment in which various embodiments can be utilized, consider now a discussion of a portable computing device with wireless connectivity, in accordance with one or more embodiments.

Antenna Configuration for a Portable Computing Device

Computing devices today often times include wireless capabilities to connect with other devices. To communicate information back and forth, the computing devices establish a wireless link that conforms to predefined protocol and frequency standards. A wireless link can be more powerful than a wired link in that it provides more freedom to the connecting devices. A device can connect wirelessly to any recipient device that supports a same wireless link format without using any additional peripheral components or devices, with the added benefit of mobility. However, a wireless link is only as useful as it is reliable. For example, an unreliable or weak wireless link can lead to a higher percentage of faulty data transfers when compared to a stable and reliable wireless link. Choosing the proper antenna for a computing device can improve the reliability of its wireless link.

Consider again the above example ofFIG. 1, where a portable computing device establishes a wireless link with another device. To maintain wireless link108, portable computing device102uses antenna112to propagate and receive wireless signals. Being a form of electromagnetic radiation, the wireless signals propagated between the respective devices adhere to various wave properties, such as reflection, refraction, scattering, absorption, polarization, etc. Thus, the environment in which an antenna operates can affect the efficiency of how the antenna propagates and receives wireless signals. Accordingly, using a design based upon an expected operating environment improves an antenna's efficiency. For instance, in the case of portable computing device102, the expected operating environment of antenna112includes an environment that changes location regularly, and has a close proximity to a user's person.

One type of antenna design is a dipole antenna. A dipole antenna consists of two conductive components that are usually symmetrical in length. In a half-wave dipole antenna, each pole has length of

λ4,
where λ represents a free-space wavelength corresponding to a frequency at which the dipole antenna is resonant. When an antenna is resonant, waves of current and voltage traveling between the arms of the antenna create a standing wave. Further, the antenna has its lowest imaginary component of the impedance at its resonant frequency, thus simplifying impedance matching between the antenna and transmission lines for transmission or reception. In turn, this condition tends to maximize both the radiation efficiency of the antenna, and the effective transfer of power to/from the antenna from/to its associated transceiver relative to other frequencies. Hence, a half-wave dipole antenna is a type of canonical reference antenna which is considered ideal for applications like mobile wireless connectivity. Accordingly, an antenna's resonant frequency can be controlled by various types of adjustments to the antenna length, radius, and so forth. In some cases, the length of each pole of a half-wave dipole antenna may be slightly adjusted from exactly

λ4
to account for real world implementations, target resonant frequencies, etc. It is to be appreciated by one skilled in the art that the above discussion has been simplified, and is not intended to describe all technical aspects of antenna design.

When considering a dipole antenna in the context of a portable computing device, such as portable computing device102ofFIG. 1, some issues arise. When vertical, a dipole antenna ideally radiates an omnidirectional pattern which yields comprehensive coverage, but in real-world applications the radiation pattern may deviate from the ideal pattern. However, a vertical antenna protruding out of a computing device worn by a user is less desirable, since it extends the size and form factor of the portable computing device, and is more susceptible to being caught on other objects or breaking. An alternative to a vertical and protruding antenna is incorporating the antenna into the device mount, such as the wristband as described with reference toFIG. 1. This can also be undesirable to the user, as it couples operations of the portable computing device to the device mount, and further constrains the user's flexibility to that particular device mount.

An alternative to incorporating an antenna into the device mount is to locate the antenna within a housing structure of the computing device itself, and decouple the antenna from the device mount. In turn, this allows a user to remove the device mount without affecting operation of the computing device. This can be achieved in any suitable manner. For instance, an Inverted-F antenna, which is a variation of a monopole antenna, is a type of antenna configured to lie horizontal. As indicated by its name, a monopole antenna consists of a single antenna pole fed against a ground plane instead of a second pole as seen in the two-pole implementation of a dipole antenna. An advantage the monopole antenna has over the dipole antenna is a reduced physical size for a same resonant frequency. To implement an Inverted-F antenna, the single antenna pole folds down from a vertical position to lie horizontal and parallel to ground. The antenna pole is shorted to ground at a first location, with the feed to the antenna pole being placed at a second location. Careful selection of the first location of the short to ground, and the second location of the feed, impacts various parameters of the antenna, such as capacitance and/or input impedance.

A Planar Inverted-F Antenna (PIFA) is a variation of an Inverted-F antenna that replaces the antenna pole with an antenna plane. Generally speaking, the resonant frequency and frequency bandwidth associated with a PIFA can be determined or managed through the size, shape, length, and/or relative spacing of the corresponding ground plane and antenna plane, as well as the location and dimensions of the shortening pin. One characteristic of a PIFA is that it is resonant at a physical dimension of a nominal quarter-wavelength

(e.g.,λ4)
or less, based on consideration that it is a type of monopole with additional electrical loading via the shorting pin. Thus, as in the above case of the Inverted-F antenna, a PIFA has a more compact size than a dipole antenna, and can be useful when incorporated into a portable computing device. In some embodiments, all or part of a PIFA can be built into the housing of a device, such as housing structure110ofFIG. 1.

ConsiderFIG. 2, which illustrates a simplified model of a PIFA, generally indicated here as antenna200. As one skilled in the art will appreciate, the corresponding discussion is intended to aid in the understanding of various embodiments, and is not intended describe all technical aspects of a PIFA.

Antenna200consists of antenna plane202and ground plane204. Here, antenna plane202and ground plane204are positioned generally parallel to one another. The term “generally” is used to signify that, while ideally antenna plane202and ground plane204should be oriented ideally parallel to one another, real world conditions allow for antenna orientations that deviate from being ideally parallel, but still sustain a standing wave and/or maintain successful operation of wireless communications. However, any other suitable shape can be utilized, such as a rectangular shape, a square shape, a circular shape, a triangular shape, and so forth. The shape of antenna plane202or ground plane204can be disproportionate, such as a shape that includes prongs, tines, or fingers that extend out. Some embodiments use a smooth plane surface, in which the corresponding surface has been sealed, or cracks have been electrically shorted together, to close surface gaps and/or create a solid surface, as further described below. In other embodiments, the planes include holes or vents, include etching on a corresponding surface, include prongs or tines that extend out, and so forth. In some embodiments, the shape of antenna plane202differs from the shape of ground plane204, while in other cases, the planes are uniform in shape. Antenna plane202and ground plane204can also have different sizes relative to one another. For example, ground plane204can have a larger size relative to antenna plane202. The variation in size and shape of antenna plane202and ground plane204, whether individually or relative to one another, can be chosen based upon an overall target range of operational frequencies, a target frequency bandwidth, or a target resonant frequency of the resultant antenna. As in the case above, the phrases “target range of operational frequencies”, “target frequency bandwidth” and “target resonant frequency” are used to indicate frequency bandwidths/ranges and resonant frequencies at which the corresponding antenna radiates (or receives) more efficiently relative to other frequency bandwidths and frequencies and/or frequencies at which the antenna is operable.

The positioning of antenna plane202and ground plane204to one another includes a spacing between the planes, indicated here as gap206. Having this gap allows a potential (voltage) difference to exist between the planes, thus causing antenna200to radiate. The dimensions of antenna plane202and ground plane204, the spacing of gap206, and the location and dimension of a feed source (illustrated as feed connection208) and a shorting pin (illustrated as ground connection210) determine the electrical performance of antenna200. In general terms, these factors determine a frequency of resonance where antenna200radiates more efficiently relative to other frequencies, and energy is maximally coupled to it from the associated transceiver, relative to other frequencies. Among other things, the height of the gap206influences the frequency bandwidth of efficient operation and, to some extent, the radiation efficiency in a corresponding bandwidth. Gap206can be empty (e.g., an air gap) or can alternately include a low-loss dielectric spacer for additional support between the planes and/or to provide a controlled spatial gap between the planes. In the case of antenna200including a low-loss dielectric in gap206, the dielectric constant of the corresponding material can also affect the operational frequencies of the antenna.

Antenna plane202and ground plane204are electrically connected through feed connection208and ground connection210. Feed connection208drives antenna plane202with the signal to be radiated, while ground connection210acts as an electrical short. These two connections have a relative positioning between them, generally indicated as length212. As discussed above, the relative positioning between feed connection208and ground connection210influences various characteristics of antenna200, such as its input impedance, which can additionally affect operation of the antenna (e.g., target resonant frequencies, operational frequency bandwidth, etc.). Accordingly, the resonant frequencies of antenna200can be influenced by multiple parameters, as further described above and below.

In some embodiments, a portable computing device incorporates an antenna for wireless connectivity by employing a PIFA using its housing and/or components partially or fully enclosed within the housing. ConsiderFIG. 3, which illustrates a cross-section view of computing device300. For the purposes of this discussion, computing device300is illustrated as a wristwatch that a user can wear or mount onto their person. However, it is to be appreciated that portable computing device300can be implemented as any other suitable computing device without departing from the scope of the claimed subject matter.

Computing device300generally has two separate sections: upper partition302and lower partition304. Among other things, upper partition302includes a front housing structure306and antenna plane308(shaded here in grey). Rather than having a separate antenna component, computing device300uses portions of front housing structure306to construct antenna plane308. In some cases, antenna plane308is created by combining additional components with front housing structure. For example, upper partition302also includes display component310, which can include any combination of components associated with a device display, such as a display assembly, a display bezel, glass, a touch screen, a display element, flexes containing electrical routing, discrete electrical components to support display operation, an NFC coil, a ferrite, and so forth. Some embodiment leverage and combine a flat metal surface of a display bezel contained within display component310with the front housing structure to form an antenna plane.

Consider antenna plane202ofFIG. 2, which is illustrated as having a darker outer ring in black, and an inner flat surface shaded in grey. Following this model, some embodiments construct antenna plane308using front housing structure306as an outer structure (such as a ring or oval), and a metal bottom surface of the display bezel as the inner surface. The outer (ring) structure is electrically joined to the metal surface to create antenna plane308from inherent components contained within upper partition302, rather than incorporating a separate and distinct antenna. How and where front housing structure306connects with the display bezel also impacts the resonant frequencies of resultant antenna plane308, as further described below.

Lower partition304includes ground plane312(shaded in solid grey), battery314and Printed Circuit Board (PCB)316(shaded with a dotted pattern). Battery314provides electrical power to computing device300, while PCB316contains components that, in combination, implement various functionality and/or features of computing device300, such as a clock source, memory storage for software applications, timekeeping, programmable logic, wireless link capabilities, and so forth. Battery314has an electrical connection into PCB316as a way to transfer power. One or both of these components can additionally include an isolating element that prevents any other electrical contacts between the two. For example, the compact nature of how the components are arranged within lower partition304situates battery314on top of PCB316. An insulator positioned between the battery and the PCB allows the two components to fit within lower partition304and prevents any unintended electrical contact.

Ground plane312generally represents a shared ground across computing device300. Here, ground plane312is illustrated as a rectangular box on top of battery314to further emphasize its relative positioning to antenna plane308. In some embodiments, various components within the lower partition inherently construct the ground plane. For instance, ground plane312can be inherently constructed from various components by keeping all metal portions of lower partition304, or of metal components enclosed within lower partition304, below a top surface of battery314. The relative positioning of ground plane312to antenna plane308is further detailed in image318, which shows a magnified view of a portion of computing device300. As can be seen, antenna plane308and ground plane312are positioned generally parallel to one another, in a manner similar to antenna plane202and ground plane204ofFIG. 2. Antenna plane308and ground plane312additionally include a space between them, indicated here as gap320. Similar to gap206ofFIG. 2, gap320represents an air gap, or dielectric spacer, with a predetermined distance or spacing between the two planes that enables a standing wave to form. Gap320can be any suitable distance, such as a length on the order of millimeters that ranges from a size greater than 0 mm up to generally 2.0 mm (e.g., 0.5 mm, 1.1 mm, 2.0 mm, 2.1 mm, etc.), a length on the order centimeters, and so forth. In some cases, the distance of gap320is defined based upon a design trade-off between a target resonant frequency, frequency bandwidth, and power efficiency versus a resultant size or height of computing device300. Some embodiments fill gap320with a low-loss dielectric, a Teflon™ spacer, or other material to add structure and stability to computing device300without impeding wireless connectivity.

A portable computing device with multiple wireless capabilities adds more flexibility for a user than a device with only a single wireless capability. For instance, a user may desire a Bluetooth™ wireless link between external speakers and the portable computing device in order to control media playback. The user may also desire Internet connectivity through a WiFi connection, the ability to send Short Message Service (SMS) text messages, or communicate over a cellular network. Thus, various embodiments configure a single antenna to operate over a wide band of frequencies that spans from a low band frequency, such as 700 MHz, to a high band frequency, such as 2700 MHz. As previously discussed, various parameters associated with the size, shape, gap distance, gap material (e.g., air versus dielectric), ground shorting position, and feed position can be selected and applied to antenna plane308and ground plane312in order to configure computing device300to support wide frequency ranges. However, other parameters can affect the efficiency of an antenna of a portable computing device, particularly when it is worn by a user.

In order to communicate with one another and work in concert, various components contained within upper partition302and lower partition304are electrically connected, generally represented here as connection322. In some cases, connection322comprises a cable or flex connector containing multiple various connections. Here, connection322connects to PCB316to display component310, but other suitable connections can be used as well. Among other things, connection322establishes a pathway for communication between components, such as PCB316receiving touch input information generated from user interaction with display component310and/or PCB316driving display of content at display component310. However, these electrical connections can impact or impede the operation of the antenna incorporated into computing device300(e.g. antenna plane308and ground plane312). Accordingly, some embodiments place the corresponding ground connection or shorting pin between antenna plane308and ground plane312nominally coincident to connection322as a way to maintain the intended functionality of the antenna (e.g. target resonant frequency, target frequency bandwidth, etc.). Alternately or additionally, connection322can be used as the ground connection and/or shorting pin between the antenna plane and the ground plane.

This is further illustrated in image324, which shows a magnified view of computing device300where connection322and antenna plane308meet. In image324, antenna plane308is segmented with a first portion positioned on the left side of connection322and a second portion positioned on the right side of connection322. Ground connection326electrically joins connection322with antenna plane308on the left side, while ground connection328electrically joins connection322with antenna plane308on the right side. The position of these ground connections, as well as the usage of connection322to establish a common ground, can impact how efficiently the antenna resonates, such as how efficiently it resonates at lower frequencies (e.g., 700-900 MHz).

FIG. 4illustrates environment400in which computing device300is being worn by a user. Here, computing device300is mounted to arm402, but for simplicity's sake, this illustration does not include the device mount mechanism (e.g., wristbands). Image404shows an enlarged view of a portion of computing device300relative to arm402. As discussed above, upper housing406(shaded using a diagonal striped shading pattern) includes the antenna plane of a PIFA (shaded using a solid grey pattern). Portions or all of upper housing406are constructed using a metal or other material suitable for supporting a standing wave current distribution. To enclose its various components, computing device also includes lower housing408(shaded using a cross-hatch pattern). Since lower housing408mounts to arm402, it consists of a non-conductive or non-metal material, such as a plastic. When joined together, upper housing406and lower housing408create the overall structure of computing device300. However, this presents various issues to be considered when designing the overall size of computing device300.

Generally, users are more likely to wear a computing device with a smaller form or size than a computing device that is perceived as being heavy, bulky, large, or awkward. Thus, it is desirable to design a computing device that is perceived as being compact and light. When considering a computing device that is mounted to a user, the compact size can adversely affect an antenna's efficiency. Consider length410, which represents the distance between the metal structure of upper housing406(which is connected to the device's antenna) and arm402. As an antenna moves closer to arm402, it dissipates more power (e.g., more waves are absorbed by the user). Conversely, as the distance increases between the antenna and the user, less power is dissipated or lost. Accordingly, if power dissipation were the only concern with respect to computing device300, length410would ideally have a length that reduces or eliminates any power dissipation into arm402. However, it is likely that such a length would generate a chassis size or height that is undesirable to a user. Thus, the selection of length410may not only be based on finding an optimal value that only focuses on power dissipation. Instead, the resultant distance for length410can be based upon balancing the opposing needs of reducing power dissipation into arm402, while still maintaining an overall form factor or height of the housing structure of computing device300that is acceptable to a user. In other words, length410might represent a distance that is sub-optimal for power dissipation and/or sub-optimal for a desired user form factor, but adequately addresses both at the same time. Any suitable distance can be selected for length410, such as a distance that generally ranges on the order of millimeters (e.g., 5 mm, 7 mm, 10 mm), a distance generally on the order of centimeters (cm) (e.g., 1 cm, 1.2 cm, 2 cm, etc.), and so forth. As in the case above, the term “generally” is used here to indicate that, due to real-world conditions, various embodiments deviate from being exactly 5 mm, 7 mm, 10 mm, etc., but are within a range that, when rounded to a nearest whole number, signify these values.

Some embodiments design the antenna of computing device300based upon an intended operating environment. Consider againFIG. 4in which computing device300is mounted to a user's arm. When mounted and/or placed on a user's arm, the arm acts as an extended ground plane. In turn, this improves the antenna's radiation efficiency at lower frequencies, such as generally 700-900 MHz than when computing device300is not mounted to/unmounted from a user. Accordingly, computing device300can incorporate an antenna that is considered electrically small for these lower frequencies when unmounted to a user's arm, but have improved performance of an electrically larger antenna when mounted by the user.

Another parameter that can affect the operation, efficiency, and/or resonant frequencies of a PIFA is the construction of its corresponding antenna plane and/or ground plane. For example, consider antenna plane308ofFIG. 3. As previously discussed, some embodiments electrically connect a front housing structure with a display bezel layer to create the antenna plane. In such a scenario, having a smooth and flat antenna plane helps establish the electromagnetic field between the antenna plane and the ground plane. However, electrically connecting and sealing these two pieces together can pose certain challenges when there are opposing design guidelines. From a mechanical standpoint, it is desirable to have fewer connections, while from an electrical standpoint, it is desirable to have many connections in order prevent energy from being trapped in the display layers. Thus, some embodiments find a balance between these opposing design guidelines by determining a number of electrical connections that is sufficient to connect and seal the two components to enable the antenna to operate over a desired range of frequencies and/or a target resonant frequency, but also reduces the number of connections to address the mechanical concerns. In some embodiments, the number of connection points is based upon a target resonant frequency, such as a value generated by

λ8,λ10,
etc., where λ represents the highest operating frequency of the antenna. Thus, as in the case above, the selection of the number of connection points can be sub-optimal for mechanical purposes and/or sub-optimal for a target resonant frequency, but adequately addresses both at the same time such that the antenna remains operational.

By modifying various parameters of an antenna implementation, a portable computing device can inherently incorporate an antenna capable of wireless communications over a wide band of frequencies while decoupling the computing device from external components. This allows for additional benefits to the user. For example, in the case of a portable computing device in the form of a wrist-wearable watch, an antenna plane made from inherent components decouples the watch from its wristband. That is, when a wristband incorporates an antenna, the computing device is dependent upon that particular wristband in order to maintain a wireless link. This can prevent the user from additional flexibility, such as using more traditional materials for a wristband. Conversely, when the wristband is the decoupled from the operations of the watch (e.g., the antenna is not included or built into the wristband, and the wristband is decoupled from wireless communications performed by the watch and/or wireless communications the watch is designed to perform), the user has more control over the look and feel of the watch. A decoupled wristband can also affect the comfort of the watch. For instance, when a wristband incorporates an antenna, the hinge used to connect the wristband to the watch conforms to design needs that ensure the antenna radiates at desired frequencies and has an electric connection to the watch. This can compromise a user's comfort in wearing the hinge by affecting the corresponding shape. Conversely, when the wristband is decoupled from the watch, a hinge can be designed for comfort without the added design constraints associate of wristband that incorporates an antenna.

Another benefit to using inherent components of a portable computing device to construct the antenna plane of a PIFA relates to testing. In order to transmit wireless signals, the Federal Communications Commission (FCC) has various standards or tests outlined for devices to pass in order to be in compliance. Having all radiating elements contained within the body of the portable computing device simplifies the testing process by making the testing process more straightforward by eliminating multiple variations and combinations of antenna elements.

Incorporating a PIFA into a portable computing device also has a benefit related to the size and shape of the computing device. Relative to other antenna implementations, a PIFA has a smaller size for a same resonant frequency. Through careful design selections, parameters can be chosen to create an electrically small antenna. Here, the term “electrically small” is used to indicate that the volume/size of the antenna is smaller than its corresponding radian sphere based upon the radiating wavelength in free space. In turn, this helps reduce the size of devices incorporating the antenna.

FIG. 5illustrates a flow chart that describes steps in a method in accordance with one or more embodiments. The method can be performed by any suitable hardware, software, firmware, or combination thereof. In at least some embodiments, aspects of the method can be implemented using portable computing device102ofFIG. 1.

Step500uses at least one component contained within a housing structure of a portable computing device to construct an antenna plane of a PIFA. As further described above, some embodiments electrically connect a front housing structure contained within an upper partition of the housing structure with a display component to create the antenna plane. The portable computing device can be any suitable type of device, such as a wrist-wearable watch. The PIFA can be partially or entirely contained within the housing structure.

Step502uses a ground plane contained within the housing structure to construct the PIFA by positioning the ground plane generally parallel to the antenna plane. In some cases, the ground plane resides in a lower partition of the housing structure, where the lower partition and the upper partition join together to create the housing structure of the portable computing device. The structure of the PIFA can maintain a spatial gap between ground plane and the antenna plane, where the spatial gap can be an air-gap, can include a Teflon™ spacer, or any other suitable material. At times the spatial gap has a length associated with one or more resonant frequencies of the PIFA.

Step504maintains at least one wireless link between the portable computing device and another device using the PIFA to transmit and receive wireless signals (and, subsequently, transmitting and receiving information via the wireless signals). In some cases, the antenna transmits signals over a wide band of frequencies, such as a frequency range spanning from about and generally between 700 MHz up to 2700 MHz. Some embodiments maintain multiple wireless links, where each wireless link is implemented using a respective format and/or protocol, while other embodiments simply maintain a single format.

Having considered a discussion of an antenna configuration with respect to a portable computing device, consider now a discussion of an example device that can be utilized to implement the embodiments described above.

Example Device

FIG. 6illustrates various components of an example electronic device600that can be utilized to implement the embodiments described herein. Electronic device600can be, or include, many different types of devices capable of transmitting over a wide band of frequencies using an internal antenna, such as portable computing device102ofFIG. 1. In some embodiments, electronic device600is a wrist-wearable electronic device.

Electronic device600includes portable computing device602and device mount604. Here, device mount604represents a mounting mechanism external to portable computing device602that can be used wear or mount portable computing device602to a person. While this example includes device mount604, other embodiments omit device mount604or configure device mount604as being removable from electronic device600, thus making device mount604optional to electronic device600. Device mount604can be made of any suitable type of material, and have any suitable shape, examples of which are provided above.

Portable computing device602includes housing component606to house or enclose various components within the computing device. Housing component606can be a single solid piece, or be constructed from multiple pieces. In some embodiments, housing component606includes an upper partition and a lower partition that join together to form the housing component. The housing component can be constructed from any suitable material, such as metal, silicone, plastic, injection molding, and so forth. In the cases where housing component606is constructed from multiple pieces, each piece can be of a same material, or can incorporate different materials from one another.

Housing component606includes antenna608. The inclusion of antenna608in housing component606indicates here that antenna608is at least partially constructed from housing component606, examples of which are described herein. In some embodiments, antenna608is constructed using portions of housing component606and portions of various components, boards, or circuits that are enclosed or contained within the housing structure, such as display component610. For example, in some embodiments, antenna608is a PIFA, where the antenna plane is inherently constructed using portions of housing component606and display component(s)610, and the ground plane is constructed from various other components enclosed partially or fully within the housing component. Antenna(s)608receives an electrical signal generated by portable computing device602, and propagates a corresponding electromagnetic wave. Similarly, antenna(s)608receives or detects electromagnetic waves propagating in free space, and converts these waves into corresponding electrical signals detectable by portable computing device602.

Display component(s)610generally represent components used to display content to a user, and can include a display assembly and a display bezel. These display components can be partially or fully supported within housing component606. In some cases, the display components enable a user to enter input to portable computing device602in order to direct its respective functionality, such as through a touch-screen interface.

Portable computing device602also includes wireless link component(s)612which are used here to generally represent hardware, software, firmware, or any combination thereof, that is used to establish, maintain, and communicate over a wireless link. Wireless link component(s)612work in conjunction with antenna608to send, receive, encode, and decode corresponding messages communicated via the wireless signals, and can be enclosed partially or fully within housing component606. The wireless link components can be multipurpose (e.g., support multiple different types of wireless links) or can be single purpose. Portable computing device602can include multiple types of wireless link components to support multiple wireless communication paths, or simply include a set of wireless link components configured for a single wireless communication path.

Portable computing device602of this example includes processor(s)614(e.g., any of application processors, microprocessors, digital-signal processors, controllers, and the like) or a processor and memory system (e.g., implemented in a system-on-chip), which processes computer-executable instructions to control operation of the device. A processing system may be implemented at least partially in hardware, which can include components of an integrated circuit or on-chip system, digital-signal processor, application-specific integrated circuit, field-programmable gate array, a complex programmable logic device, and other implementations in silicon and other hardware.

Portable computing device602also includes computer-readable media616that enables data storage, examples of which include random access memory (RAM), non-volatile memory (e.g., read-only memory (ROM), flash memory, EPROM, EEPROM, etc.), and a disk storage device. Computer-readable media616is implemented at least in part as a physical device that stores information (e.g., digital or analog values) in storage media, which does not include propagating signals or waveforms. The storage media may be implemented as any suitable types of media such as electronic, magnetic, optic, mechanical, quantum, atomic, and so on. Computer-readable media616provides data storage mechanisms to store device data618. Here, device data618is used to generally represent data, executable instructions that can be processed by processor(s)614, or any other type of information that is storable.

Alternatively, or in addition, the electronic device can be implemented with any one or combination of software, hardware, firmware, or fixed-logic circuitry that is implemented in connection with processing and control circuits, which are generally identified at620(processing and control620). Although not shown, portable computing device602can include a system bus, crossbar, interlink, or data-transfer system that couples the various components within the device. A system bus can include any one or combination of different bus structures, such as a memory bus or memory controller, data protocol/format converter, a peripheral bus, a universal serial bus, a processor bus, or local bus that utilizes any of a variety of bus architectures.

It is to be appreciated that while electronic device600includes distinct components, this is merely for illustrative purposes, and is not intended to be limiting. For example, some embodiment may exclude various components listed in electronic device600. In view of the many possible embodiments to which the principles of the present discussion may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of the claims. Therefore, the techniques as described herein contemplate all such embodiments as may come within the scope of the following claims and equivalents thereof.