U.S. patent application number 16/582769 was filed with the patent office on 2021-03-25 for electrical balanced duplexer-based duplexer.
The applicant listed for this patent is Apple Inc.. Invention is credited to Joonhoi Hur, Nedim Muharemovic, Rastislav Vazny.
Application Number | 20210091917 16/582769 |
Document ID | / |
Family ID | 1000005444616 |
Filed Date | 2021-03-25 |
United States Patent
Application |
20210091917 |
Kind Code |
A1 |
Muharemovic; Nedim ; et
al. |
March 25, 2021 |
ELECTRICAL BALANCED DUPLEXER-BASED DUPLEXER
Abstract
An electrical balance duplexer (EBD) may be used to isolate a
transmitter and receiver that share a common antenna. By using
impedance gradients to provide impedances that cause
balance-unbalance transformers (balun) of the EBD to cut-off access
to the common antenna rather than duplicate the antenna impedance,
the EBD is balanced. Such cut-offs may have a lower insertion loss
than an EBD that merely duplicates the antenna impedance to
separate the differential signals of the receiver/transmitter from
the common mode signal.
Inventors: |
Muharemovic; Nedim;
(Nuremberg, DE) ; Hur; Joonhoi; (Sunnyvale,
CA) ; Vazny; Rastislav; (Sunnyvale, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Apple Inc. |
Cupertino |
CA |
US |
|
|
Family ID: |
1000005444616 |
Appl. No.: |
16/582769 |
Filed: |
September 25, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H03H 11/344 20130101;
H04B 1/16 20130101; H04B 1/04 20130101; H03H 11/28 20130101; H04L
5/1461 20130101; H03H 7/42 20130101 |
International
Class: |
H04L 5/14 20060101
H04L005/14; H04B 1/04 20060101 H04B001/04; H04B 1/16 20060101
H04B001/16; H03H 11/28 20060101 H03H011/28; H03H 11/34 20060101
H03H011/34; H03H 7/42 20060101 H03H007/42 |
Claims
1. An electronic device, comprising: an antenna; a transmitter
configured to transmit outgoing signals using the antenna; a
receiver configured to receive incoming signals via the antenna;
and a duplexer configured to enable the transmitter and receiver to
use the antenna for incoming and outgoing signals, wherein the
duplexer comprises an electrical balancing duplexer comprising:
transmitter balun circuitry including a transmitter impedance
gradient and a transmitter balun that has a first side of the
transmitter balun coupled to the transmitter and a second side of
the transmitter balun coupled to the transmitter impedance
gradient, wherein the transmitter impedance gradient is configured
to provide a gradient of impedances to cause the transmitter balun
to: filter a receive frequency to block the outgoing signals from
traversing the transmitter balun to the antenna; and enable the
transmitter balun to pass the outgoing signals at a transmit
frequency through the transmitter balun to enable the outgoing
signals to be sent to the antenna from the transmitter.
2. The electronic device of claim 1, wherein the transmitter is
coupled between windings on the first side of the transmitter
balun.
3. The electronic device of claim 1, wherein the transmitter is
coupled to one end of all windings on the first side of the
transmitter balun.
4. The electronic device of claim 1, wherein the transmitter balun
circuitry comprises a transmitter impedance tuner coupled to the
second side of the transmitter balun, wherein the transmitter
impedance tuner is configured to provide a low impedance in
frequencies corresponding to the outgoing signals and to match an
impedance of the transmitter impedance gradient for the incoming
signals.
5. The electronic device of claim 1, wherein the transmitter is
configured to provide the outgoing signals to the transmitter balun
as differential signals, and the transmitter is configured to
receive the differential signals at the first side of the
transmitter at opposite ends of windings on the first side of the
transmitter balun.
6. The electronic device of claim 1, wherein the duplexer comprises
receiver balun circuitry that has a receiving impedance gradient
and a receiver balun that has a first side of the receiver balun
coupled to the receiver and a second side of the receiver balun
coupled to the receiver impedance gradient that provide a gradient
of impedances to cause the receiver balun to: filter the transmit
frequency to block the outgoing signals from traversing the
receiver balun to reach the receiver; and enable the receiver balun
to pass the incoming signals at the receive frequency through the
receiver balun to enable the outgoing signals to be sent to the
receiver from the antenna.
7. The electronic device of claim 6, wherein the receiver is
coupled between windings on the first side of the receiver
balun.
8. The electronic device of claim 6, wherein the receiver is
coupled to one end of all windings on the first side of the
receiver balun.
9. The electronic device of claim 6, wherein the receiver balun
circuitry comprises a receiver impedance tuner coupled to the
second side of the receiver balun, wherein the receiver impedance
tuner is configured to provide a low impedance in frequencies
corresponding to the incoming signals and to match an impedance of
the receiver impedance gradient for the outgoing signals.
10. The electronic device of claim 6, wherein the receiver balun is
configured to receive the incoming signals as differential signals,
and the receiver balun is configured to provide the differential
signals to the receiver from the first side of the receiver balun
at opposite ends of windings on the first side of the receiver
balun.
11. The electronic device of claim 6, wherein the duplexer
comprises: a transmitter line coupled between windings of the
second side of the transmitter balun that is configured to transmit
the outgoing signals from the transmitter balun; and a receiver
line coupled between windings of the second side of the receiver
balun that is configured to transmit the incoming signals to the
receiver balun from the antenna.
12. The electronic device of claim 11, wherein the duplexer
comprises an antenna balun that has a first side of the antenna
balun coupled to the transmitter line and the receiver line and has
a second side of the antenna balun coupled to the antenna.
13. The electronic device of claim 12, wherein the transmitter line
and the receiver line are coupled at opposite ends of windings of
the first side of the antenna balun.
14. The electronic device of claim 13, wherein the antenna and
ground are coupled to opposite ends of windings of the second side
of the antenna balun.
15. An electronic device, comprising: an antenna; a transmitter
configured to transmit outgoing signals in a transmission frequency
band using the antenna; a receiver configured to receive incoming
signals in a receive frequency band at via the antenna; and a
duplexer configured to enable the transmitter and receiver to use
the antenna for incoming and outgoing signals, wherein the duplexer
comprises an electrical balancing duplexer comprising: transmitter
balun circuitry comprising: a transmitter impedance gradient; and a
transmitter balun comprising: a first side of the transmitter balun
coupled to the transmitter and the transmitter impedance gradient;
and a second side of the transmitter balun coupled to the antenna,
wherein the transmitter impedance gradient is configured to provide
a high impedance at the first side of transmitter balun for the
transmission frequency band to enable the transmitter balun to pass
the outgoing signals from the transmitter to the antenna, and the
transmitter impedance gradient is configured to provide a first low
impedance at the first side of the transmitter balun for the
receive frequency band to enable the transmitter balun to block the
outgoing signals in the receive frequency band from traversing the
transmitter balun to the antenna; and receiver balun circuitry
comprising: a receiver impedance gradient; and a receiver balun
comprising: a first side of the receiver balun coupled to the
receiver and the receiver impedance gradient; and a second side of
the receiver balun coupled to the antenna, wherein the receiver
impedance gradient is configured to provide a high impedance at the
first side of transmitter balun for the receive frequency band to
enable the receiver balun to pass the incoming signals from the
antenna to the receiver, and the receiver impedance gradient is
configured to provide a second low impedance at the first side of
the receiver balun for the transmission frequency band to enable
the receiver balun to block the outgoing signals from traversing
the transmitter balun to the receiver.
16. The electronic device of claim 15, wherein the transmitter
balun circuitry comprises a transmitter impedance tuner coupled to
the first side of the transmitter balun, wherein the transmitter
impedance tuner is configured to provide a third low impedance in
frequencies corresponding to the outgoing signals and to match an
impedance of the transmitter impedance gradient for the incoming
signals.
17. The electronic device of claim 15, wherein the receiver balun
circuitry comprises a receiver impedance tuner coupled to the first
side of the receiver balun, wherein the receiver impedance tuner is
configured to provide a fourth low impedance in frequencies
corresponding to the incoming signals and to match an impedance of
the receiver impedance gradient for the outgoing signals.
18. A method, comprising: providing a first low impedance from a
transmitter impedance gradient to a transmitter balun for a receive
frequency band; using the first low impedance to block transmission
signals in the receive frequency band from traversing the
transmitter balun from a transmitter to an antenna; providing a
second low impedance from a receiver impedance gradient to a
receiver balun for a transmission frequency band; using the second
low impedance to block signals in the transmission frequency band
from traversing the receiver balun to a receiver; providing a first
high impedance from the transmitter impedance gradient to the
transmitter balun for the transmission frequency band; using the
first high impedance to enable signals in the transmission
frequency band to traverse the transmitter balun from the
transmitter to the antenna; providing a second high impedance from
the receiver impedance gradient to the receiver balun for the
receive frequency band; and using the second high impedance to
enable signals in the receive frequency band to traverse the
receiver balun from the antenna to the receiver.
19. The method of claim 18, comprising providing a third low
impedance to the transmitter balun for the transmission frequency
band to enhance traversal of the transmitter balun by the signals
in the transmission frequency band.
20. The method of claim 19, wherein providing the third low
impedance is performed using an impedance tuner.
21. The method of claim 19, comprising providing the first low
impedance to the transmitter balun for the receive frequency band
to aid the transmitter balun in blocking the signals in the receive
frequency band.
22. The method of claim 18, comprising providing a third low
impedance to the receiver balun for the receive frequency band to
enhance traversal of the receiver balun by the signals in the
receive frequency band.
23. The method of claim 22, wherein providing the third low
impedance is performed using an impedance tuner.
24. The method of claim 22, comprising providing the second low
impedance to the receiver balun for the transmission frequency band
to aid the receiver balun in blocking the signals in the
transmission frequency band.
Description
BACKGROUND
[0001] The present disclosure relates generally to wireless
communication systems and, more specifically, to systems and
methods for electrical balanced duplexer (EBD)-based power
amplifier duplexers (PADs).
[0002] This section is intended to introduce the reader to various
aspects of art that may be related to various aspects of the
present disclosure, which are described and/or claimed below. This
discussion is believed to be helpful in providing the reader with
background information to facilitate a better understanding of the
various aspects of the present disclosure. Accordingly, it should
be understood that these statements are to be read in this light,
and not as admissions of prior art.
[0003] Transmitters and receivers may be coupled to an antenna to
enable an antenna to both receive and transmit from an electronic
device. Certain of these electronic devices may use PADs to isolate
the transmitter and receiver ports from each other and control
connection of the transmitters/receivers to the antenna. The PADs
may include multiple duplexers and switches to provide isolation
between the transmitter and receiver ports. Since the applications
for the antenna, the transmitters, and the receivers may be
diverse, the PADs may include numerous band pass filters that are
frequency-dependent. In other words, to increase flexibility
additional band pass filters may be added to the PAD. However,
additional band pass filters consume additional space and add costs
to manufacture of the electrical device.
SUMMARY
[0004] A summary of certain embodiments disclosed herein is set
forth below. It should be understood that these aspects are
presented merely to provide the reader with a brief summary of
these certain embodiments and that these aspects are not intended
to limit the scope of this disclosure. Indeed, this disclosure may
encompass a variety of aspects that may not be set forth below.
[0005] Certain wireless electronic devices use duplexers to enable
transmitters and receivers to share an antenna. In some situations,
the electronic device may be used across multiple different
frequencies. An electrical balance duplexer (EBD) may be used to
accommodate dynamic frequency usage compared to arrays of pass-band
filters. The EBD may include balance-unbalance transformer (balun)
circuits that include respective baluns that are coupled to
impedance gradients that provide a respective impedance at a
corresponding frequency to enable/block traversal of the balun. For
example, some embodiments, may include a transmitter balun that is
configured to receive a first impedance (e.g., a high impedance) at
a first frequency from a transmitter impedance gradient to block
signals from the antenna from crossing the transmitter balun to the
transmitter while enabling signals from the transmitter to traverse
the transmitter balun using a second impedance (e.g., a low
impedance) at a second frequency from the transmitter impedance
gradient. This frequency division is applied by the EBD because the
first and second frequencies are different. For instance, the first
and second frequency may fall in different (i.e., non-overlapping
frequency bands).
[0006] A receiver balun may function similarly to the transmitter
balun. For example, the receiver balun that is configured to
receive a first impedance at a first frequency from a receiver
impedance gradient to block signals from the transmitter from
crossing the receiver balun to the receiver while enabling signals
from the antenna to traverse the receiver balun using a second
impedance at a second frequency from the receiver impedance
gradient. This frequency division is applied by the EBD because the
first and second frequencies are different. For instance, the first
and second frequency may fall in different (i.e., non-overlapping
frequency bands).
[0007] In some embodiments, the impedance gradients may be assisted
using impedance tuners that reduce demands on the impedance
gradients. For example, the impedance tuners may provide a low
impedance in a pass band while matching an impedance of a
corresponding impedance gradient in a block band.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Various aspects of this disclosure may be better understood
upon reading the following detailed description and upon reference
to the drawings in which:
[0009] FIG. 1 is a block diagram of an electronic device that
includes a duplexer, in accordance with an embodiments of the
present disclosure;
[0010] FIG. 2 is a perspective view of a notebook computer
representing an embodiment of the electronic device of FIG. 1;
[0011] FIG. 3 is a front view of a hand-held device representing
another embodiment of the electronic device of FIG. 1;
[0012] FIG. 4 is a front view of another hand-held device
representing another embodiment of the electronic device of FIG.
1;
[0013] FIG. 5 is a front view of a desktop computer representing
another embodiment of the electronic device of FIG. 1;
[0014] FIG. 6 is a front view and side view of a wearable
electronic device representing another embodiment of the electronic
device of FIG. 1;
[0015] FIG. 7 is a schematic diagram of the duplexer of FIG. 1
having an electrical balance duplexer (EBD), in accordance with
embodiments of the present disclosure;
[0016] FIG. 8 is a schematic diagram for an alternative embodiment
of the EBD of FIG. 7 having a transmitter impedance gradient and a
receiver impedance gradient, in accordance with embodiments of the
present disclosure;
[0017] FIG. 9 is a schematic diagram of the EBD of FIG. 8 with the
transmitter impedance gradient causing a transmitter balun to
enable transmission of signals to an antenna and the receiver
impedance gradient causing a receiver balun to block transmission
of the signals to the receiver, in accordance with embodiments of
the present disclosure;
[0018] FIG. 10 is a schematic diagram of the EBD of FIG. 8 with the
transmitter impedance gradient causing a transmitter balun to block
transmission of signals having a transmission frequency from the
transmitter to an antenna and the receiver impedance gradient
causing a receiver balun to enable transmission of signals having a
receive frequency to the receiver, in accordance with embodiments
of the present disclosure;
[0019] FIG. 11 is a schematic diagram of the EBD of FIG. 8 with
impedance tuners for each impedance gradient, in accordance with
embodiments of the present disclosure;
[0020] FIG. 12 is a schematic diagram of the EBD of FIG. 11 with
differential signals to be transmitted from the transmitter and
differential signals to be received by the receiver, in accordance
with embodiments of the present disclosure;
[0021] FIG. 13 is an alternative embodiment of the EBD of FIG. 8
with the impedance gradients and impedance tuners on a same side of
a corresponding balun with the transmitter/receiver, in accordance
with embodiments of the present disclosure; and
[0022] FIG. 14 is a block diagram of process used by the EBD of
FIGS. 8-13, in accordance with embodiments of the present
disclosure.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0023] One or more specific embodiments will be described below. In
an effort to provide a concise description of these embodiments,
not all features of an actual implementation are described in the
specification. It should be appreciated that in the development of
any such actual implementation, as in any engineering or design
project, numerous implementation-specific decisions must be made to
achieve the developers' specific goals, such as compliance with
system-related and business-related constraints, which may vary
from one implementation to another. Moreover, it should be
appreciated that such a development effort might be complex and
time consuming, but would nevertheless be a routine undertaking of
design, fabrication, and manufacture for those of ordinary skill
having the benefit of this disclosure.
[0024] Electronic devices may utilize one or more duplexers.
Duplexers are devices that enable bidirectional communication over
a single path while separating components that utilize the single
path. For example, duplexers may separate a receiver for the
electronic device from a transmitter for the electronic device that
both share an antenna of the electronic device. Conventional
duplexers may include filters of any kind to achieve this
separation. For example, duplexers may include surface-acoustic
wave (SAW) filters and/or bulk-acoustic waves (BAW) filters based
on microacoustic principles or may include an
inductor-capacitor-resistor (LCR) filter based on resonating
circuits of inductors and capacitors to separate the transmitter
and the receiver.
[0025] In addition to or alternative to SAW/BAW filters, a CMOS
N-Path filter, a spatio-temporal circulator, or an electrical
balanced duplexer (EBD) may be used in the duplexers. The EBD is a
duplexer, which uses a balance-unbalance transformer (balun) in
order to separate the differential signal from the common mode
signal.
[0026] A substantial disadvantage of using the N-Path filter,
spatio-temporal circulator, or the EBD exists in that these
technologies have a higher insertion loss compared to using SAW/BAW
filters. A further drawback regarding the EBD is that the
traditional EBD uses an active replica of an antenna impedance in
order to reach a highest isolation. Any antenna impedance shift may
disturb the duplex function and degrade the isolation between the
transmit path and the receive path. As discussed below in more
detail, the EBD discussed herein differs from traditional EBDs in
that a balun of the disclosed EBD in a balanced state is used to
cut off the path to the antenna and not just to separate the
differential signals of the receiver/transmitter from the common
mode signal.
[0027] With the foregoing in mind, there are many suitable
electronic devices that may benefit from the embodiments of
duplexers described herein. Turning first to FIG. 1, an electronic
device 10 according to an embodiment of the present disclosure may
include, among other things, one or more processor(s) 12, memory
14, nonvolatile storage 16, a display 18, antenna(s) 20, input
structures 22, an input/output (I/O) interface 24, a network
interface 25, and a power source 29. The various functional blocks
shown in FIG. 1 may include hardware elements (including
circuitry), software elements (including computer code stored on a
computer-readable medium), or a combination of both hardware and
software elements. It should be noted that FIG. 1 is merely one
example of a particular implementation and is intended to
illustrate the types of components that may be present in
electronic device 10.
[0028] By way of example, the electronic device 10 may represent a
block diagram of the notebook computer depicted in FIG. 2, the
handheld device depicted in FIG. 3, the handheld device depicted in
FIG. 4, the desktop computer depicted in FIG. 5, the wearable
electronic device depicted in FIG. 6, or similar devices. It should
be noted that the processor(s) 12 and other related items in FIG. 1
may be generally referred to herein as "data processing circuitry."
Such data processing circuitry may be embodied wholly or in part as
software, firmware, hardware, or any combination thereof.
Furthermore, the data processing circuitry may be a single
contained processing module or may be incorporated wholly or
partially within any of the other elements within the electronic
device 10.
[0029] In the electronic device 10 of FIG. 1, the processor(s) 12
may be operably coupled with the memory 14 and the nonvolatile
storage 16 to perform various algorithms. Such programs or
instructions executed by the processor(s) 12 may be stored in any
suitable article of manufacture that includes one or more tangible,
computer-readable media at least collectively storing the
instructions or routines, such as the memory 14 and the nonvolatile
storage 16. The memory 14 and the nonvolatile storage 16 may
include any suitable articles of manufacture for storing data and
executable instructions, such as random-access memory, read-only
memory, rewritable flash memory, hard drives, and optical discs. In
addition, programs (e.g., an operating system) encoded on such a
computer program product may also include instructions that may be
executed by the processor(s) 12 to enable the electronic device 10
to provide various functionalities.
[0030] In certain embodiments, the display 18 may be a liquid
crystal display (LCD), which may allow users to view images
generated on the electronic device 10. In some embodiments, the
display 18 may include a touch screen, which may allow users to
interact with a user interface of the electronic device 10.
Furthermore, it should be appreciated that, in some embodiments,
the display 18 may include one or more organic light emitting diode
(OLED) displays, or some combination of LCD panels and OLED
panels.
[0031] The input structures 22 of the electronic device 10 may
enable a user to interact with the electronic device 10 (e.g.,
pressing a button to increase or decrease a volume level). The I/O
interface 24 may enable electronic device 10 to interface with
various other electronic devices, as may the network interface 25.
The network interface 25 may include, for example, one or more
interfaces for a personal area network (PAN), such as a Bluetooth
network, for a local area network (LAN) or wireless local area
network (WLAN), such as an 802.11x Wi-Fi network, and/or for a wide
area network (WAN), such as a 3rd generation (3G) cellular network,
universal mobile telecommunication system (UMTS), 4th generation
(4G) cellular network, long term evolution (LTE) cellular network,
or long term evolution license assisted access (LTE-LAA) cellular
network, 5th generation (5G) cellular network, and/or 5G New Radio
(5G NR) cellular network. The network interface 25 may also include
one or more interfaces for, for example, broadband fixed wireless
access networks (WiMAX), mobile broadband Wireless networks (mobile
WiMAX), asynchronous digital subscriber lines (e.g., ADSL, VDSL),
digital video broadcasting-terrestrial (DVB-T) and its extension
DVB Handheld (DVB-H), ultra-Wideband (UWB), alternating current
(AC) power lines, and so forth. For example, network interfaces 25
may be capable of joining multiple networks, and may employ one or
more antennas 20 to that end. Additionally or alternatively, the
network interfaces 25 may include at least one duplexer 26 that
enables multiple components (e.g., the receiver 27 and the
transmitter 28) with separate paths (e.g., transmit path and
receive path) to use one of the antennas 20 while providing
separation between the multiple components. As further illustrated,
the electronic device 10 may include a power source 29. The power
source 29 may include any suitable source of power, such as a
rechargeable lithium polymer (Li-poly) battery and/or an
alternating current (AC) power converter.
[0032] In certain embodiments, the electronic device 10 may take
the form of a computer, a portable electronic device, a wearable
electronic device, or other type of electronic device. Such
computers may include computers that are generally portable (such
as laptop, notebook, and tablet computers) as well as computers
that are generally used in one place (such as conventional desktop
computers, workstations, and/or servers). In certain embodiments,
the electronic device 10 in the form of a computer may be a model
of a MACBOOK.RTM., MACBOOK.RTM. PRO, MACBOOK AIR.RTM., IMAC.RTM.,
MAC.RTM. MINI, OR MAC PRO.RTM. available from Apple Inc. By way of
example, the electronic device 10, taking the form of a notebook
computer 10A, is illustrated in FIG. 2 in accordance with one
embodiment of the present disclosure. The depicted computer 10A may
include a housing or enclosure 36, a display 18, input structures
22, and ports of an I/O interface 24. In one embodiment, the input
structures 22 (such as a keyboard and/or touchpad) may be used to
interact with the computer 10A, such as to start, control, or
operate a GUI or applications running on computer 10A. For example,
a keyboard and/or touchpad may allow a user to navigate a user
interface or application interface displayed on display 18.
[0033] FIG. 3 depicts a front view of a handheld device 10B, which
represents one embodiment of the electronic device 10. The handheld
device 10B may represent, for example, a portable phone, a media
player, a personal data organizer, a handheld game platform, or any
combination of such devices. By way of example, the handheld device
10B may be a model of an IPOD.RTM. OR IPHONE.RTM. available from
Apple Inc. of Cupertino, Calif. The handheld device 10B may include
an enclosure 36 to protect interior components from physical damage
and to shield them from electromagnetic interference. The enclosure
36 may surround the display 18. The I/O interfaces 24 may open
through the enclosure 36 and may include, for example, an I/O port
for a hardwired connection for charging and/or content manipulation
using a standard connector and protocol, such as the Lightning
connector provided by Apple Inc., a universal serial bus (USB), or
other similar connector and protocol.
[0034] User input structures 22, in combination with the display
18, may allow a user to control the handheld device 10B. For
example, the input structures 22 may activate or deactivate the
handheld device 10B, navigate user interface to a home screen, a
user-configurable application screen, and/or activate a
voice-recognition feature of the handheld device 10B. Other input
structures 22 may provide volume control, or may toggle between
vibrate and ring modes. The input structures 22 may also include a
microphone may obtain a user's voice for various voice-related
features, and a speaker may enable audio playback and/or certain
phone capabilities. The input structures 22 may also include a
headphone input may provide a connection to external speakers
and/or headphones.
[0035] FIG. 4 depicts a front view of another handheld device 10C,
which represents another embodiment of the electronic device 10.
The handheld device 10C may represent, for example, a tablet
computer, or one of various portable computing devices. By way of
example, the handheld device 10C may be a tablet-sized embodiment
of the electronic device 10, which may be, for example, a model of
an IPAD.RTM. available from Apple Inc. of Cupertino, Calif.
[0036] Turning to FIG. 5, a computer 10D may represent another
embodiment of the electronic device 10 of FIG. 1. The computer 10D
may be any computer, such as a desktop computer, a server, or a
notebook computer, but may also be a standalone media player or
video gaming machine. By way of example, the computer 10D may be an
IMAC.RTM., a MACBOOK.RTM., or other similar device by Apple Inc. It
should be noted that the computer 10D may also represent a personal
computer (PC) by another manufacturer. A similar enclosure 36 may
be provided to protect and enclose internal components of the
computer 10D such as the display 18. In certain embodiments, a user
of the computer 10D may interact with the computer 10D using
various input structures 22, such as the keyboard 22A or mouse 22B,
which may connect to the computer 10D.
[0037] Similarly, FIG. 6 depicts a wearable electronic device 10E
representing another embodiment of the electronic device 10 of FIG.
1 that may be configured to operate using the techniques described
herein. By way of example, the wearable electronic device 10E,
which may include a wristband 38, may be an APPLE WATCH.RTM. by
Apple Inc. However, in other embodiments, the wearable electronic
device 10E may include any wearable electronic device such as, for
example, a wearable exercise monitoring device (e.g., pedometer,
accelerometer, heart rate monitor), or other device by another
manufacturer. The display 18 of the wearable electronic device 10E
may include a touch screen display 18 (e.g., LCD, OLED display,
active-matrix organic light emitting diode (AMOLED) display, and so
forth), as well as input structures 22, which may allow users to
interact with a user interface of the wearable electronic device
10E.
[0038] With the foregoing in mind, FIG. 7 illustrates an embodiment
of the duplexer 26 that includes an EBD 41. As illustrated, the EBD
41 provides isolation between the receiver 27 and the transmitter
28 while enabling both the receiver 27 and the transmitter 28 to
utilize the antenna 20. As illustrated, the duplexer 26 may include
a low-noise amplifier (LNA) 42 that may be used to amplify received
signals for the receiver 27. In some embodiments, an iteration of
the LNA 42 may be located within the receiver 27 in addition to or
alternative the LNA 42 within the duplexer 26. In some embodiments,
an iteration of the LNA 42 may be located within the receiver 27 in
addition to or alternative the LNA 42 within the duplexer 26. The
duplexer 26 may also include a power amplifier (PA) 43 that
receives signals from the transmitter 28. The PA 43 amplifies the
signals to a suitable level to drive the transmission of the
signals via the antenna 20. In some embodiments, an iteration of
the PA 43 may be located within the transmitter 28 in addition to
or alternative the PA 43 within the duplexer 26. These signals are
to be transmitted via the antenna 20.
[0039] The EBD 41 includes a secondary winding 45 that may be used
to selectively pass a signal from the antenna to the LNA 42 (and to
the receiver 27) via primary windings 46 and/or 47. Signals from
the PA 43 (and from the transmitter 28) are passed to antenna 20
via a line 48 coupled between the primary windings 46 and 47. A
balancing network 49 of the EBD 41 may be used to actively
replicate an impedance of the antenna 20 to maximize isolation
between the receiver 27 and the transmitter 28. However, if the
impedance of the antenna 20 shifts, a duplexer function of the
duplexer 26 is disturbed and the isolation between the receiver 27
and the transmitter 28 are degraded. Instead, the duplexer 26 may
use an alternative arrangement of the EBD 41, such as embodiments
of the duplexer 26 illustrated in FIGS. 8-13, that reduce the
insertion loss resulting from using the EBD 41 in FIG. 7 while
eliminating the antenna replica dependency of FIG. 7 to improve
flexibility of frequencies used in the duplexer 26.
[0040] FIG. 8 is a simplified block diagram of an embodiment of the
duplexer 26 with an EBD 41 that does not include the antenna
replica dependency present in FIG. 7. As illustrated, the duplexer
26 is coupled to the antenna 20 and provides selective access to
and from the antenna 20 by the receiver 27 and the transmitter 28
of the electronic device 10. The duplexer 26 includes transmitter
balun circuitry 58 having a transmitter balun 59 and receiver balun
circuitry 60 having a receiver balun 61. The transmitter 28 is
coupled to a first side of the transmitter balun 59 while the
receiver 27 is coupled to a corresponding first side of the
receiver balun 61.
[0041] The transmitter balun circuitry 58 and the receiver balun
circuitry 60 each enables a corresponding path (e.g., between the
antenna 20 and the receiver 27/the transmitter 28) to be blocked or
allowed. This selective blocking/passing may be set for the
transmitter balun circuitry 58 using an impedance gradient 62
coupled to a second side of the transmitter balun 59 opposite the
connection to the transmitter 28, and the state may be set for the
receiver balun circuitry 60 using an impedance gradient 64 coupled
to a second side of the receiver balun 61 opposite the connection
to the receiver 27. The impedance gradients 62 and 64 may be
implemented using discrete lumped components or distributed
components that set desired impedances for certain frequencies and
may couple certain frequencies to ground 65 with a low impedance.
Regardless of implementation type, the impedance gradients 62 and
64 act as filters having a relative high impedance in a "pass" band
compared to a relative low impedance (e.g., short to ground 65) in
a "block" band.
[0042] Furthermore, the transmitter balun 59 includes a winding 66
that may produce an electromagnetic field due to excitation due to
the connection of the winding 66 to the transmitter 28 and a common
return 68 (e.g., ground). The field generated at the winding 66 may
cause resulting signals in windings 70 and/or 72 depending on the
frequency range of the signals and the impedance provided by the
impedance gradient 62 in that frequency range. The impedance
gradient 62 is coupled to the winding 70 and a connection of the
winding 72 to a common return 74. A line 76 is coupled between the
windings 70 and 72 to enable the signals from the transmitter 28 to
the antenna 20 via an antenna balun 77 when the transmitter balun
59 is set to pass transmission signals using the impedance
gradients 62 and/or 64.
[0043] The receiver balun 61 includes a winding 78 that may
generate a signal based on an electromagnetic field generated by
windings 80 and/or 82 based on the impedance gradient 64 providing
an impedance to the receiver balun 61 that enables passing of
signals across the receiver balun 61. A line 84 between the
windings 80 and 82 couples the pair of windings 80 and 84 to the
antenna balun 77. Specifically, the lines 76 and 84 are coupled to
opposite ends of a winding 86 of the antenna balun 77. The
impedance gradients 62 and 64 cause a transmission signal to be
passed to the line 76, when the duplexer 26 permits transmission of
signals having a transmission frequency. The passing of the
transmission signal causes the winding 86 to generate an
electromagnetic field that induces a signal on a secondary winding
88 of the antenna balun 77 that is passed to the antenna 20 to be
broadcast.
[0044] The impedance gradients 62 and 64 cause a received signal to
be passed from the antenna to the receiver 27, when the duplexer 26
permits signals having a receive frequency using an impedance from
the impedance gradient 64. Although the illustrated embodiment
includes a single antenna balun 77 to provide connection to the
antenna 20, any other suitable implementation used to transmit
signals between the antenna 20 and a corresponding lines 76 and
84.
[0045] FIG. 9 is a schematic diagram illustrating the duplexer 26
in a transmission mode for at least one transmission frequency. As
previously noted, the impedance gradient 62 acts a filter that
provides a high impedance for a pass band. For example, the
impedance gradient 62 may select an "open" position 100 instead of
a "short" position 102. The "open" position 100 connects the
winding 70 to a relatively high impedance compared to a relatively
low impedance provided when the short position 102 is selected to
provide a low impedance path to ground 65. As illustrated, the
impedance gradient 62 may be in a transmission mode for the
transmission frequency. With the impedance gradient 62 configured
to provide a high impedance path for the winding 80 at the
transmission frequency, transmission signals from the transmitter
28 are passed in a transmission path 104 across the transmitter
balun 59 and ultimately to the antenna 20.
[0046] The impedance gradient 64 functions similar to the impedance
gradient 62 except that the impedance gradient 64 is to block
transmission frequencies from being transmitted to the receiver 27
when in the transmission frequency. To achieve this isolation, the
impedance gradient 64 is set to select between coupling the winding
80 to a "open" position 106 and a "short" position 108, each
respectively similar to the "open" position 100 and the "short"
position 102. Since the duplexer 26 is to block the transmission
frequency from the receiver 27, the impedance gradient 64 provides
a low impedance connection to the winding 80 for the transmission
frequency. With the impedance gradient 62 configured to provide a
low impedance path for the winding 80 at the transmission
frequency, transmission signals from the antenna 20 are passed in a
transmission path 110 until being stopped from transference across
the receiver balun 61 due to the low impedance connection provided
by the impedance gradient 64 to the winding 80.
[0047] Since the EBD 41 has two impedance gradients 62 and 64 that
may be controlled individually and block corresponding frequencies,
the EBD 41 may be used to implement the duplexer 26 as a frequency
division duplexer. FIG. 10 is a schematic diagram illustrating the
duplexer 26 for at least one receive frequency. The receiver mode
of the duplexer 26 for the receive frequency includes the impedance
gradient 62 coupling the winding 70 to a low impedance path causing
a transmission path 112 to be blocked preventing transference of
transmission signals across the transmitter balun 59. Furthermore,
the receiver mode of the duplexer 26 for the receive frequency
includes the impedance gradient 64 coupling the winding 80 to a
high impedance path causing received signals to be passed along a
receive path 114 from the antenna 20 to the receiver 27 via
receiver balun 61.
[0048] With the impedance gradient 62 configured to provide a high
impedance path for the winding 80 at the transmission frequency,
transmission signals from the transmitter 28 are passed in a
transmission path 104 across windings 66 and 72 to the line 76 and
ultimately to the antenna 20.
[0049] Since the impedance gradients 62 and 64 may be implemented
using real-word components, the high impedance and low impedance
settings for impedance gradients 62 and 64 may be values other than
ideal short and open values (e.g., 0.OMEGA. and .infin..OMEGA.). To
address the non-ideal operation of the impedance gradients 62 and
64, an additional component, an impedance tuner, may be used to
compensate for such non-ideal values of impedances. Furthermore, a
concern in operation of the EBD 41 can be an abrupt change in
impedance at the transmission and receive frequencies. By using the
impedance tuner, the demands on the impedance gradients 62 and 64
may also be reduced. FIG. 11 illustrates an embodiment of the
duplexer 26 with impedance tuners 120 and 122. Whereas the
impedance gradients 62 and 64 act as filters, the impedance tuners
120 have a low impedance in the "pass" band for the respective
balun and replicates the impedance of the corresponding impedance
gradient in the "block" band. In other words, in some embodiments,
the impedance tuners 120 and 122 may always provide a low impedance
lower than the high impedance of a corresponding impedance gradient
for passed frequencies while providing a similar low impedance that
is provided by the corresponding impedance gradient for blocked
frequencies.
[0050] The illustrated embodiment of the EBD 41 in FIG. 11 also
includes windings 124 and 126 that respectively supplement the
windings 66 and 78. However, in some embodiments, the windings 66
and 124 may be combined into a single winding, and the windings 78
and 126 may be combined into a single winding.
[0051] Since signals to the receiver 27 and from the transmitter 28
may be differential signals, some embodiments of the EBD 41 may
address differential transmittance of such signals. For instance,
in FIG. 12, the EBD 41 includes a positive transmitter terminal 130
and a negative transmitter terminal 132 that together form a
differential signal from the transmitter 28 (e.g., via the PA 43).
Thus, in the EBD 41 of FIG. 12, the transmitter balun 59 may be
used to convert the differential signal from the transmitter 28 to
a single signal on the line 76. Similarly, the EBD 41 of FIG. 12
includes a positive receiver terminal 134 and a negative receiver
terminal 136 that together form a differential signal to the
receiver 27 (e.g., via the LNA 42). Thus, in the EBD 41 of FIG. 12,
the receiver balun 61 may be used to convert the single signal on
the line 84 to a differential signal suitable for the receiver
27.
[0052] The impedance gradients 62 and 64 and the impedance tuners
120 and 122 have been illustrated on as coupled to the
corresponding baluns at a side opposite side (e.g., secondary
winding-side of the transmitter balun 59) than the receiver 27 or
the transmitter 28 in the foregoing embodiments. However, the
impedance gradients 62 and 64 and the impedance tuners 120 and 122
may be coupled to the same respective side (e.g., the primary
winding-side of the transmitter balun 59) as the receiver 27 or the
transmitter 28. FIG. 13 illustrates a schematic diagram of an
embodiment of the duplexer 26 having such an arrangement. As
illustrated, the transmitter 28 is coupled to the transmitter balun
59 between the windings 66 and 124, and the receiver 27 is coupled
to the receiver balun 61 between the windings 78 and 126. Moreover,
the impedance gradient 62 is coupled between the winding 66 and
ground 65 instead of between the winding 70 and ground 65
illustrated in previous embodiments. Furthermore, the impedance
tuner 120 is coupled between the winding 124 and ground 65 instead
of between the winding 72 and ground 65 illustrated in previous
embodiments. Moreover, the impedance gradient 64 is coupled between
the winding 78 and ground 65 instead of between the winding 82 and
ground 65 illustrated in previous embodiments. Furthermore, the
impedance tuner 122 is coupled between the winding 126 and ground
65 instead of between the winding 80 and ground 65 illustrated in
previous embodiments. In some embodiments, the impedance tuners 120
and 122 may be omitted from the duplexer 26 of FIG. 13.
[0053] FIG. 14 is flow diagram of a process 200 that may be used by
the embodiments of the EBD 41 discussed in relation to FIGS. 8-13.
The process 200 includes the impedance gradient 62 providing a
first low impedance to the transmitter balun 59 for a receive
frequency band (block 202). The transmitter balun 59 uses the first
low impedance to block transmission signals in the receive
frequency band from traversing the transmitter balun 59 from the
transmitter 28 to the antenna 20 (block 204). The impedance
gradient 64 provides a second low impedance to the receiver balun
61 for a transmission frequency band (block 206). The first low
impedance and the second low impedance may be the same impedance
level or may be different impedance levels. The receiver balun 61
then uses the second low impedance to block signals in the
transmission frequency band from traversing the receiver balun 61
to the receiver 27 (block 208).
[0054] The impedance gradient 62 also provides a first high
impedance to the transmitter balun 59 for the transmission
frequency band (block 210). The transmitter balun 59 uses the first
high impedance to enable signals in the transmission frequency band
to traverse the transmitter balun 59 from the transmitter 28 to the
antenna 20 (block 212). The impedance gradient 64 provides a second
high impedance to the receiver balun No errors found 61 for the
receive frequency band (block 214). The receiver balun 61 uses the
second high impedance to enable signals in the receive frequency
band to traverse the receiver balun 61 from the antenna 20 to the
receiver 27 (block 216).
[0055] In addition, the impedance tuner 120 provides a third low
impedance to the transmitter balun 59 for the transmission
frequency band to enhance traversal of the transmitter balun 59 by
the signals in the transmission frequency band. The third low
impedance may be equal the first low impedance and/or the second
low impedance. Alternatively, the third low impedance may be
different than the first low impedance and the second low
impedance. The impedance tuner 120 also provides the first low
impedance to the transmitter balun 59 for the receive frequency
band to aid the transmitter balun in blocking the signals in the
receive frequency band.
[0056] The impedance tuner 122 provides a fourth low impedance to
the receiver balun 61 for the receive frequency band to enhance
traversal of the receiver balun 61 by the signals in the receive
frequency band. The fourth low impedance may be equal the first low
impedance, the second low impedance, and/or the third low
impedance. Alternatively, the fourth low impedance may be different
than the first low impedance, the second low impedance, and the
third low impedance. The impedance tuner 122 also provides the
second low impedance to the receiver balun 61 for the transmission
frequency band to aid the receiver balun 61 in blocking the signals
in the transmission frequency band.
[0057] The specific embodiments described above have been shown by
way of example, and it should be understood that these embodiments
may be susceptible to various modifications and alternative forms.
For example, the methods may be applied for embodiments having
different numbers and/or locations for antennas, different
groupings, and/or different networks. It should be further
understood that the claims are not intended to be limited to the
particular forms disclosed, but rather to cover all modifications,
equivalents, and alternatives falling within the spirit and scope
of this disclosure.
[0058] The techniques presented and claimed herein are referenced
and applied to material objects and concrete examples of a
practical nature that demonstrably improve the present technical
field and, as such, are not abstract, intangible or purely
theoretical. Further, if any claims appended to the end of this
specification contain one or more elements designated as "means for
[perform]ing [a function] . . . " or "step for [perform]ing [a
function] . . . ", it is intended that such elements are to be
interpreted under 35 U.S.C. 112(f). However, for any claims
containing elements designated in any other manner, it is intended
that such elements are not to be interpreted under 35 U.S.C.
112(f).
* * * * *