Note: Descriptions are shown in the official language in which they were submitted.
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MOBILE WIRELESS COMMUNICATIONS DEVICE INCLUDING ANTENNA
ASSEMBLY HAVING SPACED APART PARALLEL CONDUCTOR ARMS AND
RELATED METHODS
Technical Field
[0001] The present disclosure generally relates to the
field of wireless communications systems, and, more
particularly, to mobile wireless communications devices and
related methods.
Background
[0002] Mobile wireless communications systems continue to
grow in popularity and have become an integral part of both
personal and business communications. For example, cellular
telephones allow users to place and receive voice calls almost
anywhere they travel. Moreover, as cellular telephone
technology has increased, so too has the functionality of
cellular devices and the different types of devices available
to users. For example, many cellular devices now incorporate
personal digital assistant (PDA) features such as calendars,
address books, task lists, etc. Moreover, such multi-function
devices may also allow users to wirelessly send and receive
electronic mail (email) messages and access the Internet via a
cellular network and/or a wireless local area network (WLAN),
for example.
[0003] Even so, as the functionality of cellular
communications devices continues to increase, so too does the
demand for smaller devices which are easier and more
convenient for users to carry. One challenge this poses for
cellular device manufacturers is designing antennas that
provide desired operating characteristics within the
relatively limited amount of space available for antennas.
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Brief Description of the Drawings
[0004] FIG. 1 is a top plan view of a mobile wireless
communications device including an antenna assembly in
accordance with one example embodiment.
[0005] FIG. 2 is a schematic block diagram of the device of
FIG. 1.
[0006] FIG. 3 is a perspective view of a portion of the
substrate of the device in FIG. 2 including the antenna.
[0007] FIG. 4a is a simulated current distribution graph
for the antenna assembly of FIG. 2 for the common mode.
[0008] FIG. 4b is a simulated current distribution graph
for the antenna assembly of FIG. 2 for the slot mode.
[0009] FIG. 5 is a graph of measured return loss and
efficiency for an antenna assembly similar to FIG. 2.
[0010] FIG. 6 is a schematic diagram of a flexible
substrate and an antenna assembly in accordance with another
example embodiment.
[0011] FIG. 7a is a graph of measured efficiency in the
global positioning system frequency band for an antenna
assembly similar to FIG. 6.
[0012] FIG. 7b is a graph of measured efficiency in the
wireless local area network frequency band for an antenna
assembly similar to FIG. 6.
[0013] FIG. 7c is a graph of measured S parameters for an
antenna assembly similar to FIG. 6.
[0014] FIG. 8 is a schematic block diagram illustrating
additional components that may be included in the mobile
wireless communications device of FIG. 1.
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Detailed Description
[0015] The present description is made with reference to
the accompanying drawings, in which various embodiments are
shown. However, many different embodiments may be used, and
thus the description should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure will be thorough and
complete. Like numbers refer to like elements throughout, and
prime notation is used to indicate similar elements or steps
in alternative embodiments.
[0016] In accordance with one exemplary aspect, a mobile
wireless communications device may include a portable housing,
at least one wireless transceiver carried by the portable
housing, and at least one satellite positioning signal
receiver carried by the portable housing. The mobile wireless
communications device may also include an antenna assembly
carried by the portable housing, for example. The antenna
assembly may include a base electrical conductor having a pair
of antenna feed points defined therein and coupled to the at
least one wireless transceiver and the at least one satellite
signal positioning receiver. The antenna assembly may also
include first and second conductor arms being spaced apart,
parallel, and extending outwardly from the base electrical
conductor, for example.
[0017] The antenna assembly may further include a
dielectric substrate supporting the base electrical conductor
and the first and second conductor arms. The dielectric
substrate may include a flexible dielectric substrate, for
example. The mobile wireless communications device may
further include at least one electronic component carried by
the dielectric substrate.
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[0018] The first and second conductor arms each have a same
length, for example. The first and second conductor arms may
have a rectangular shape.
[0019] The pair of antenna feed points may include a pair
of shorted antenna feed points, for example. The mobile
wireless communications device may further include an
impedance matching circuit carried by the housing and coupled
to the antenna assembly. The antenna assembly may be
configured to operate in at least one of a global positioning
system (GPS) band, a wireless local area network (WLAN) band,
and a personal area network (PAN) band.
[0020] Another example aspect is directed to a mobile
wireless communications device that may include a portable
housing, at least one wireless transceiver carried by the
portable housing, and an antenna assembly carried by the
portable housing, for example. The antenna assembly may
include a base electrical conductor having a slot therein
defining pair of antenna feed points and coupled to the at
least one wireless transceiver. The antenna assembly may
further include first and second conductor arms being spaced
apart, parallel, and extending outwardly from the base
electrical conductor, the first and second conductor arms
being angled with respect to the slot.
[0021] A method aspect is directed to a method of making an
antenna assembly for a mobile wireless communications device
that may include a portable housing, at least one wireless
transceiver carried by the portable housing, and at least one
satellite positioning signal receiver carried by the portable
housing. The method may include forming a base electrical
conductor having a pair of antenna feed points and to be
coupled to the at least one wireless transceiver, and the at
least one satellite positioning signal receiver. The method
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may also include forming first and second parallel conductor
arms being spaced apart, parallel, and extending outwardly
from the base electrical conductor.
[0022] Another method aspect is direct to a method of
forming a mobile wireless communications device including a
portable housing, at least one wireless transceiver carried by
the portable housing, and an antenna assembly carried by the
portable housing. The method may include forming a base
electrical conductor having a slot therein defining pair of
antenna feed points and coupled to the at least one wireless
transceiver, for example. The method may also include forming
first and second conductor arms being spaced apart, parallel,
and extending outwardly from the base electrical conductor,
the first and second conductor arms being angled with respect
to the slot.
[0023] Referring initially to FIGS. 1-3, a mobile wireless
communications device 30 illustratively includes a portable
housing 31 and a dielectric substrate 32, for example, a
printed circuit board (PCB), carried by the portable housing.
The portable housing 31 has an upper portion and a lower
portion. A wireless transceiver 33 is carried by the portable
housing 31. In some embodiments, not shown, the dielectric
substrate 32 may be replaced by or used in conjunction with a
metal chassis or other substrate. The dielectric substrate 32
may also include a conductive layer (not shown) defining a
ground plane.
[0024] A satellite positioning signal receiver 34 is also
carried by the portable housing 31. The satellite positioning
signal receiver 34 may be a Global Positioning System (GPS)
satellite receiver, for example.
[0025] The exemplary device 30 further illustratively
includes a display 60 and a plurality of control keys
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including an "off hook" (i.e., initiate phone call) key 61, an
"on hook" (i.e., discontinue phone call) key 62, a menu key
63, and a return or escape key 64. Operation of the various
device components and input keys, etc., will be described
further below with reference to FIG. 8.
[0026] The device 30 further illustratively includes an
antenna assembly 35 carried adjacent the upper portion of the
portable housing 31. The antenna assembly 35 is
advantageously a two-arm planar inverted F-antenna (PIFA) that
may be tuned to different frequency bands, for example. The
antenna assembly 35 illustratively includes a base electrical
conductor 36 supported by the dielectric substrate 32. The
base electrical conductor 36 has a pair of shorted antenna
feed points 37a, 37b defined therein by a base electrical
conductor slot 46. The pair of shorted antenna feed points
37a, 37b may not be defined by the base electrical conductor
slot 38, for example. In other words, the base electrical
conductor 37 may not include the base electrical conductor
slot 46. The base electrical conductor slot 46 advantageously
tunes the impedance of the antenna assembly 35. The shorted
antenna feed points 37a, 37b, are coupled to the wireless
transceiver 33 and the satellite positioning receiver 34. In
some embodiments, the antenna feed points 37a, 37b may not be
shorted. The first and second conductive feeds 47a, 47b may be
coupled between the shorted feed points 37a, 37b and the
dielectric substrate 32 to space the antenna assembly above
the dielectric substrate 32 (FIG. 3).
[0027] The antenna assembly 35 also includes first and
second conductor arms 43, 44 extending outwardly from the base
electrical conductor 36 and supported by the dielectric
substrate 32. The first and second conductor arms 43, 44 are
illustratively rectangular in shape and spaced apart and
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parallel. In other words, the first and second conductor 43,
44 arms may resemble a tuning fork. The first and second
conductor arms 43, 44 may be other shapes.
[0028] As will be appreciated by those skilled in the art,
the length of the first and second conductor arms 43, 44 may
be tuned to excite the common mode. The first and second arms
have an equal length so that they may be tuned to resonate at
1.575 GHz, which is advantageously in the GPS frequency band.
Of course, the length of the first and second conductor arms
43, 44 may be different and may be tuned to resonate at
another frequency within another frequency band.
[0029] The length of the slot 41, or space between the
first and second conductor arms 43, 44 advantageously may be
tuned to excite the slot mode. For example, the length of the
slot 41 may be tuned to resonate at 2.4 GHz, which is
advantageously in the wireless local/personal area network
(WLAN/PAN), Bluetooth, WiFi frequency band. Of course, the
length of the slot 41 may be tuned to resonate at another
frequency within another frequency band.
[0030] A matching circuit 45 may be carried by the housing
31 and/or dielectric substrate 32, and coupled to the antenna
assembly 35. The matching circuit 45 may further improve
impedance matching of the antenna assembly 35, as will be
appreciated by those skilled in the art. Other or additional
circuitry or electric components may also be carried by the
housing 31 and/or dielectric substrate 32.
[0031] A controller 38 or processor may also be carried by
the PCB 32. The controller 38 may cooperate with the other
components, for example, the antenna assembly 35, the
satellite positioning signal receiver 34, and the wireless
transceiver 33 to coordinate and control operations of the
mobile wireless communications device 30. Operations may
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include mobile voice and data operations, including email and
Internet data.
[0032] Referring now the graphs 48, 49 in FIGS. 4a and 4b,
respectively, the simulated surface currents for the antenna
assembly 35 illustrated in FIGS. 2 and 3 are illustrated.
More particularly, the graph 48 in FIG. 4a illustrates the
surface current for the antenna assembly 35 operating in the
common mode at 1.575 GHz. The graph 49 in FIG. 4b illustrates
the surface current for the antenna assembly 35 operating in
the slot mode at 2.45 GHz.
[0033] Referring now to the graph 50 FIG. 5, measured
performance in free space for an antenna assembly similar to
the antenna assembly 35 illustrated in FIGS. 2 and 3 and
having a shorted trace with the matching circuit 45 is
illustrated. The measured performance is illustratively
measured by return loss in dB and efficiency at the given
frequencies. The return loss 51 is illustratively reduced
near the GPS and WiFi frequency bands, i.e. 1.575 GHz and 2.4
GHz, respectively. The efficiency at the GPS frequency band
52 illustratively about 24%. The efficiency at the WiFi
frequency band 53 is illustratively between about 49-52%.
[0034] Referring now to FIG. 6, in another example
embodiment, the antenna assembly 35' may be carried by a
flexible dielectric substrate 39'. The antenna assembly 35'
may be a printed pattern on the flexible dielectric substrate
39', or may be implemented thereon by other selective plating
technologies, for example, laser direct structuring (LDS) or
2-shot molding.
[0035] The flexible dielectric substrate 39' may be
included with another PCB (not shown), for example, the device
PCB, for carrying other components or circuitry, for example,
the controller 38', the display 60', the wireless transceiver
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33', and the satellite positioning signal receiver 34'. The
flexible dielectric substrate 39' may advantageously allow for
conforming of the antenna assembly 35' with the back of the
portable housing 31'. The flexible substrate 39' may include
an adhesive layer (not shown), for example, a pressure
sensitive adhesive, on an underside thereof to mount with the
mobile wireless communications device 30'. A copper layer
(not shown) may be carried on a front side of the flexible
substrate 39'.
[0036] Additional circuitry may be carried by the flexible
substrate 39'. For example, a microphone (not shown) may be
carried by the flexible substrate 39'. A camera flash 59' may
also be carried by the flexible substrate 39' adjacent ends of
the first and second conductor arms 43', 44' opposite the base
electrical conductor 36'. A switch circuit 53' may also be
carried by the flexible substrate 39'. Other or different
electronic components may be carried by the flexible substrate
391.
[0037] The first and second conductor arms 43', 44' are
illustratively are spaced apart, parallel, and extend
outwardly from the base electrical conductor 36'. The first
and second conductor arms 43', 44' are angled with respect to
the base electrical conductor slot 46'. Illustratively, the
first and second conductor arms 43', 44' are at an angle
greater than ninety degrees with respect to the base
electrical conductor slot 46'. In other words, the first and
second conductor arms 43', 44' define an L-shape, or more
particularly, a lazy L-shape, with respect to the base
electrical conductor slot 46'. Of course, the first and
second conductors 43', 44' may be at any angle with respect to
the base electrical conductor slot 46' or may be at no angle
at all, i.e. zero degrees.
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[0038] Referring now to the graph in FIG. 7a, the measured
GPS efficiency in free space of an antenna assembly similar to
that illustrated in FIG. 6 is illustrated. The linear
efficiency 81 is about 32% across the GPS frequency band.
[0039] Referring now to the graph in FIG. 7b, the measured
WiFi efficiency in free space of the antenna assembly similar
to that illustrated in FIG. 6 is illustrated. The linear
efficiency 83 is about 40-49% across the WLAN frequency band.
[0040] Referring now to the graph in FIG. 7c, the measured
S parameters in free space of the antenna assembly similar to
that illustrated in FIG. 6 is illustrated. The return loss 85
in dB is reduced in the 1.49-1.59 GHz frequency band (i.e.
GPS), and 2.37-2.5 GHz frequency band (i.e. WLAN).
[0041] The dual band functionality of the antenna assembly
35 may be particularly useful in the design of a mobile
wireless communications device, for example, the mobile
wireless communications device 30. The antenna assembly 35
advantageously reduces space occupied in the housing 31 and
cost as compared to using two individual antennas, for
example. Indeed, while the size of the antenna assembly 35
may be reduced, the performance of the antenna assembly may be
maintained, for example, to support requirements of different
wireless service carriers.
[0042] A method aspect is directed to a method of making an
antenna assembly 35 for a mobile wireless communications
device 30 that includes a portable housing 31, a wireless
transceiver 33 carried by the portable housing, and a
satellite positioning signal receiver 34 carried by the
portable housing. The method includes forming a base
electrical conductor 36 to have a pair of antenna feed points
37a, 37b and to be coupled to the wireless transceiver 33, and
the satellite positioning signal receiver 34. The method also
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includes forming first and second parallel conductor arms 43,
44 to be spaced apart, parallel, and extend outwardly from the
base electrical conductor 36.
[0043] Another method aspect is directed to a method of
forming a mobile wireless communications device 30 including a
portable housing 31, a wireless transceiver 33 carried by the
portable housing, and an antenna assembly 35 carried by the
portable housing. The method includes forming a base
electrical conductor 36 having a slot 46 therein defining pair
of antenna feed points 37a, 37b and coupled to the wireless
transceiver 33. The method also includes forming first and
second conductor arms 43, 44 being spaced apart, parallel, and
extending outwardly from the base electrical conductor 36.
The first and second conductor arms 43, 44 are angled with
respect to the slot 46.
[0044] Example components of a mobile wireless
communications device 1000 that may be used in accordance with
the above-described embodiments are further described below
with reference to FIG. 8. The device 1000 illustratively
includes a housing 1200, a keyboard or keypad 1400 and an
output device 1600. The output device shown is a display 1600,
which may comprise a full graphic LCD. Other types of output
devices may alternatively be utilized. A processing device
1800 is contained within the housing 1200 and is coupled
between the keypad 1400 and the display 1600. The processing
device 1800 controls the operation of the display 1600, as
well as the overall operation of the mobile device 1000, in
response to actuation of keys on the keypad 1400.
[0045] The housing 1200 may be elongated vertically, or may
take on other sizes and shapes (including clamshell housing
structures). The keypad may include a mode selection key, or
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other hardware or software for switching between text entry
and telephony entry.
[0046] In addition to the processing device 1800, other
parts of the mobile device 1000 are shown schematically in
FIG. 8. These include a communications subsystem 1001; a
short-range communications subsystem 1020; the keypad 1400 and
the display 1600, along with other input/output devices 1060,
1080, 1100 and 1120; as well as memory devices 1160, 1180 and
various other device subsystems 1201. The mobile device 1000
may comprise a two-way RF communications device having data
and, optionally, voice communications capabilities. In
addition, the mobile device 1000 may have the capability to
communicate with other computer systems via the Internet.
[0047] Operating system software executed by the processing
device 1800 is stored in a persistent store, such as the flash
memory 1160, but may be stored in other types of memory
devices, such as a read only memory (ROM) or similar storage
element. In addition, system software, specific device
applications, or parts thereof, may be temporarily loaded into
a volatile store, such as the random access memory (RAM) 1180.
Communications signals received by the mobile device may also
be stored in the RAM 1180.
[0048] The processing device 1800, in addition to its
operating system functions, enables execution of software
applications 1300A-1300N on the device 1000. A predetermined
set of applications that control basic device operations, such
as data and voice communications 1300A and 1300B, may be
installed on the device 1000 during manufacture. In addition,
a personal information manager (PIM) application may be
installed during manufacture. The PIM may be capable of
organizing and managing data items, such as e-mail, calendar
events, voice mails, appointments, and task items. The PIM
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application may also be capable of sending and receiving data
items via a wireless network 1401. The PIM data items may be
seamlessly integrated, synchronized and updated via the
wireless network 1401 with corresponding data items stored or
associated with a host computer system.
[0049] Communication functions, including data and voice
communications, are performed through the communications
subsystem 1001, and possibly through the short-range
communications subsystem. The communications subsystem 1001
includes a receiver 1500, a transmitter 1520, and one or more
antennas 1540 and 1560. In addition, the communications
subsystem 1001 also includes a processing module, such as a
digital signal processor (DSP) 1580, and local oscillators
(LOs) 1601. The specific design and implementation of the
communications subsystem 1001 is dependent upon the
communications network in which the mobile device 1000 is
intended to operate. For example, a mobile device 1000 may
include a communications subsystem 1001 designed to operate
with the MobitexTM, Data TACTM or General Packet Radio Service
(GPRS) mobile data communications networks, and also designed
to operate with any of a variety of voice communications
networks, such as AMPS, TDMA, CDMA, WCDMA, PCS, GSM, EDGE,
etc. Other types of data and voice networks, both separate and
integrated, may also be utilized with the mobile device 1000.
The mobile device 1000 may also be compliant with other
communications standards such as 3GSM, 3GPP, UMTS, 4G, etc.
[0050] Network access requirements vary depending upon the
type of communication system. For example, in the Mobitex and
DataTAC networks, mobile devices are registered on the network
using a unique personal identification number or PIN
associated with each device. In GPRS networks, however,
network access is associated with a subscriber or user of a
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device. A GPRS device therefore typically involves use of a
subscriber identity module, commonly referred to as a SIM
card, in order to operate on a GPRS network.
[0051] When required network registration or activation
procedures have been completed, the mobile device 1000 may
send and receive communications signals over the communication
network 1401. Signals received from the communications network
1401 by the antenna 1540 are routed to the receiver 1500,
which provides for signal amplification, frequency down
conversion, filtering, channel selection, etc., and may also
provide analog to digital conversion. Analog-to-digital
conversion of the received signal allows the DSP 1580 to
perform more complex communications functions, such as
demodulation and decoding. In a similar manner, signals to be
transmitted to the network 1401 are processed (e.g. modulated
and encoded) by the DSP 1580 and are then provided to the
transmitter 1520 for digital to analog conversion, frequency
up conversion, filtering, amplification and transmission to
the communication network 1401 (or networks) via the antenna
1560.
[0052] In addition to processing communications signals,
the DSP 1580 provides for control of the receiver 1500 and the
transmitter 1520. For example, gains applied to communications
signals in the receiver 1500 and transmitter 1520 may be
adaptively controlled through automatic gain control
algorithms implemented in the DSP 1580.
[0053] In a data communications mode, a received signal,
such as a text message or web page download, is processed by
the communications subsystem 1001 and is input to the
processing device 1800. The received signal is then further
processed by the processing device 1800 for an output to the
display 1600, or alternatively to some other auxiliary I/O
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device 1060. A device may also be used to compose data items,
such as e-mail messages, using the keypad 1400 and/or some
other auxiliary I/O device 1060, such as a touchpad, a rocker
switch, a thumb-wheel, or some other type of input device. The
composed data items may then be transmitted over the
communications network 1401 via the communications subsystem
1001.
[0054] In a voice communications mode, overall operation of
the device is substantially similar to the data communications
mode, except that received signals are output to a speaker
1100, and signals for transmission are generated by a
microphone 1120. Alternative voice or audio I/O subsystems,
such as a voice message recording subsystem, may also be
implemented on the device 1000. In addition, the display 1600
may also be utilized in voice communications mode, for example
to display the identity of a calling party, the duration of a
voice call, or other voice call related information.
[0055] The short-range communications subsystem enables
communication between the mobile device 1000 and other
proximate systems or devices, which need not necessarily be
similar devices. For example, the short-range communications
subsystem may include an infrared device and associated
circuits and components, a BluetoothTM communications module to
provide for communication with similarly-enabled systems and
devices, or a near field communications (NFC) sensor for
communicating with a NFC device or NFC tag via NFC
communications.
[0056] Many modifications and other embodiments of the
invention will come to the mind of one skilled in the art
having the benefit of the teachings presented in the foregoing
descriptions and the associated drawings. Therefore, it is
understood that the invention is not to be limited to the
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specific embodiments disclosed, and that modifications and
embodiments are intended to be included within the scope of
the appended claims.
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