U.S. patent application number 13/188987 was filed with the patent office on 2012-01-26 for radio frequency signal processing circuit and quadrature power amplifier.
This patent application is currently assigned to MEDIATEK INC.. Invention is credited to Wen-Wei Yang.
Application Number | 20120021697 13/188987 |
Document ID | / |
Family ID | 45494026 |
Filed Date | 2012-01-26 |
United States Patent
Application |
20120021697 |
Kind Code |
A1 |
Yang; Wen-Wei |
January 26, 2012 |
RADIO FREQUENCY SIGNAL PROCESSING CIRCUIT AND QUADRATURE POWER
AMPLIFIER
Abstract
A quadrature power amplifier capable of operating in a
single-output mode and a multiple-output mode. When operating in
the single-output mode, a first quadrature coupler receives a first
input signal, and splits and phase-shifts the first input signal
into two first split signals. A first power amplifier receives and
amplifies one of the two first split signals to generate a first
amplified signal. The second power amplifier receives and amplifies
the other one of the two first split signals to generate a second
amplified signal. The second quadrature coupler receives the first
amplified signal and the second amplified signal, and phase-shifts
and combines the first amplified signal and the second amplified
signal into a first output signal.
Inventors: |
Yang; Wen-Wei; (Jhubei City,
TW) |
Assignee: |
MEDIATEK INC.
Hsin-Chu
TW
|
Family ID: |
45494026 |
Appl. No.: |
13/188987 |
Filed: |
July 22, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61367732 |
Jul 26, 2010 |
|
|
|
Current U.S.
Class: |
455/73 ;
330/124R |
Current CPC
Class: |
Y02D 30/70 20200801;
H04W 52/0251 20130101; Y02D 70/00 20180101 |
Class at
Publication: |
455/73 ;
330/124.R |
International
Class: |
H04B 1/38 20060101
H04B001/38; H03F 3/68 20060101 H03F003/68 |
Claims
1. A quadrature power amplifier, capable of operating in a
single-output mode and a multiple-output mode, comprising: a first
quadrature coupler, when operating in the single-output mode,
receiving a first input signal, splitting and phase-shifting the
first input signal into two first split signals, which are
phase-shifted substantially 90 degrees from each other; a first
power amplifier, coupled to the first quadrature coupler for
receiving and amplifying one of the two first split signals to
generate a first amplified signal; a second power amplifier,
coupled to the first quadrature coupler for receiving and
amplifying the other one of the two first split signals to generate
a second amplified signal; and a second quadrature coupler,
receiving the first amplified signal and the second amplified
signal, and phase-shifting and combining the first amplified signal
and the second amplified signal into a first output signal.
2. The quadrature power amplifier as claimed in claim 1, wherein
when operating in the multiple-output mode, the first quadrature
coupler further receives a second input signal, and splits and
phase-shifts the second input signal into two second split signals,
which are phase-shifted substantially 90 degrees from each other;
the first power amplifier further receives and amplifies one of the
two second split signals to generate a third amplified signal; the
second power amplifier further receives and amplifies the other one
of the two second split signals to generate a fourth amplified
signal; and the second quadrature coupler further receives the
third amplified signal and the fourth amplified signal, and
phase-shifts and combines the third amplified signal and the fourth
amplified signal into a second output signal.
3. The quadrature power amplifier as claimed in claim 1, wherein
the first output signal is an amplified version of the first input
signal with a predetermined phase difference.
4. The quadrature power amplifier as claimed in claim 2, wherein
the first output signal is an amplified version of the first input
signal with a first predetermined phase difference, and the second
output signal is an amplified version of the second input signal
with a second predetermined phase difference.
5. The quadrature power amplifier as claimed in claim 4, wherein
the first predetermined phase difference equals to the second
predetermined phase difference.
6. The quadrature power amplifier as claimed in claim 2, wherein
when the first input signal and the second input signal have
substantially the same phase, the first output signal and the
second output signal have substantially the same phase, and when
the first input signal and the second input signal have different
phases, the first output signal and the second output signal have
different phases.
7. A radio frequency (RF) signal processing circuit, coupled
between a transceiver module and at least a first antenna and a
second antenna, comprising: a quadrature power amplifier, capable
of operating in a single-output mode and a multiple-output mode,
and comprising a first input terminal and a second input terminal
coupled to the transceiver, and a first output terminal coupled to
the first antenna and a second output terminal coupled to the
second antenna, wherein when operating in the single-output mode,
the quadrature power amplifier receives a first input signal from
the transceiver module via the first input terminal, splits and
phase-shifts the first input signal into two first split signals,
and further amplifies and combines the two first split signals to
generate a first output signal, which is an amplified version of
the first input signal with a predetermined phase difference and is
output to one of the first and the second antennas.
8. The RF signal processing circuit as claimed in claim 7, wherein
when operating in the multiple-output mode, the quadrature power
amplifier further receives a second input signal from the
transceiver module via the second input terminal, splits and
phase-shifts the second input signal into two second split signals,
and further amplifies and combines the two second split signals to
generate a second output signal, which is an amplified version of
the second input signal with the predetermined phase difference,
and outputs the second output signal to the other one of the first
and the second antennas.
9. The RF signal processing circuit as claimed in claim 7, further
comprising: a switch device, coupled between the quadrature power
amplifier and the transceiver module, for selectively passing the
first input signal to the first input terminal or the second input
terminal in response to an antennal selection signal indicating
which antenna is selected when operating in the single-output
mode.
10. The RF signal processing circuit as claimed in claim 8, wherein
the quadrature power amplifier further comprises: a first
quadrature coupler, coupled to the first input terminal and the
second input terminal; a first power amplifier, coupled to the
first quadrature coupler; a second power amplifier, coupled to the
first quadrature coupler; and a second quadrature coupler, coupled
between to the first power amplifier, second power amplifier, the
first output terminal and the second output terminal.
11. The RF signal processing circuit as claimed in claim 10,
wherein when operating in the single-output mode, the first
quadrature coupler receives the first input signal, and splits and
phase-shifts the first input signal into the two first split
signals, which are phase-shifted substantially 90 degrees from each
other; and when operating in the multiple-output mode, the first
quadrature coupler further receives the second input signal, and
splits and phase-shifts the second input signal into the two second
split signals, which are phase-shifted substantially 90 degrees
from each other.
12. The RF signal processing circuit as claimed in claim 11,
wherein when operating in the single-output mode, the first power
amplifier receives and amplifies one of the two first split signals
to generate a first amplified signal, and the second power
amplifier receives and amplifies the other one of the two first
split signals to generate a second amplified signal; and when
operating in the multiple-output mode, the first power amplifier
further receives and amplifies one of the two second split signals
to generate a third amplified signal, and the second power
amplifier further receives and amplifies the other one of the two
second split signals to generate a fourth amplified signal.
13. The RF signal processing circuit as claimed in claim 12,
wherein when operating in the single-output mode, the second
quadrature coupler receives the first amplified signal and the
second amplified signal, and phase-shifts and combines the first
amplified signal and the second amplified signal into the first
output signal; and when operating in the multiple-output mode, the
second quadrature coupler further receives the third amplified
signal and the fourth amplified signal, and phase-shifts and
combines the third amplified signal and the fourth amplified signal
into the second output signal.
14. A radio frequency (RF) signal processing circuit, coupled
between a transceiver module and at least a first antenna and a
second antenna, comprising: a quadrature power amplifier,
comprising a first input terminal and a second input terminal
coupled to the transceiver, and a first output terminal coupled to
the first antenna and a second output terminal coupled to the
second antenna, wherein when the quadrature power amplifier
receives a first input signal and a second input signal from the
transceiver module respectively via the first input terminal and
the second input terminal, the quadrature power amplifier splits,
and phase-shifts the first input signal and the second input signal
into two first split signals and two second split signals,
respectively, and further amplifies and combines the two first
split signals and the two second split signals to respectively
generate a first output signal, which is an amplified version of
the first input signal with a first predetermined phase difference,
and a second output signal, which is an amplified version of the
second input signal with a second predetermined phase difference,
and outputs the first output signal to the second antenna and the
second output signal to the first antenna.
15. The RF signal processing circuit as claimed in claim 14,
wherein when the quadrature power amplifier receives only the first
input signal from the transceiver module via one of the first input
terminal and the second input terminal, the quadrature power
amplifier outputs only the first output signal to one of the first
and the second antennas.
16. The RF signal processing circuit as claimed in claim 15,
further comprising: a switch device, coupled between the quadrature
power amplifier and the transceiver module, for selectively passing
the first input signal to the first input terminal or the second
input terminal in response to an antennal selection signal
indicating which antenna is selected to transmit the first output
signal.
17. The RF signal processing circuit as claimed in claim 14,
wherein when the first input signal and the second input signal
have substantially the same phase, the first output signal and the
second output signal have substantially the same phase, and when
the first input signal and the second input signal have different
phases, the first output signal and the second output signal have
different phases.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/367,732 filed Jul. 26, 2010 and entitled
"Transmit Antenna Diversity for MIMO System". The entire contents
of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to a power amplifier, and more
particularly to a power amplifier capable of operating in a
single-output mode and a multiple-output mode. When operating in
the single-output mode, an extra 3 dB output power is gained as
compared to the multiple-output mode.
[0004] 2. Description of the Related Art
[0005] Portable battery powered wireless communications devices,
such as mobile terminals, cell phones, personal digital assistant,
tablet computer, and the like, often have requirements to
efficiently transmit information at different output power levels.
As a result, RF transmitter power amplifiers need to transmit using
a wide range of output power levels, while maintaining efficiency
throughout operating ranges. Conventionally, in the single uplink
path designs, when higher output power is required, a power
amplifier having larger gain is utilized. However, the power
amplifier having larger gain requires larger chip area. There is a
trade off between the chip area and the output power level
required.
[0006] Meanwhile, for the multiple uplink path designs in a
Multiple-Input-Multiple-Output (MIMO) system, the signal power may
be increased (for example, doubled) when using antenna diversity.
However, when signal loss in one signal path is serious, the
benefits of using multiple power amplifiers cannot be gained.
[0007] Therefore, a novel power amplifier capable of supporting
both single-output and multiple-output systems while maintaining
amplifying efficiency is highly required.
BRIEF SUMMARY OF THE INVENTION
[0008] A radio frequency signal processing circuit and a quadrature
power amplifier are provided. An embodiment of a quadrature power
amplifier capable of operating in a single-output mode and a
multiple-output mode comprises a first quadrature coupler, a first
power amplifier, a second power amplifier and a second quadrature
coupler. When operating in the single-output mode, the first
quadrature coupler receives a first input signal, and splits and
phase-shifts the first input signal into two first split signals,
which are phase-shifted substantially 90 degrees from each other.
The first power amplifier receives and amplifies one of the two
first split signals to generate a first amplified signal. The
second power amplifier receives and amplifies the other one of the
two first split signals to generate a second amplified signal. The
second quadrature coupler receives the first amplified signal and
the second amplified signal, and phase-shifts and combines the
first amplified signal and the second amplified signal into a first
output signal.
[0009] An embodiment of a radio frequency (RF) signal processing
circuit coupled between a transceiver module and at least a first
antenna and a second antenna comprises a quadrature power
amplifier. The quadrature power amplifier is capable of operating
in a single-output mode and a multiple-output mode, and comprises a
first input terminal and a second input terminal coupled to the
transceiver, and a first output terminal coupled to the first
antenna and a second output terminal coupled to the second antenna.
When operating in the single-output mode, the quadrature power
amplifier receives a first input signal from the transceiver module
via the first input terminal, splits and phase-shifts the first
input signal into two first split signals, and further amplifies
and combines the two first split signals to generate a first output
signal, which is an amplified version of the first input signal
with a predetermined phase difference and is output to one of the
first and the second antennas.
[0010] Another embodiment of a radio frequency (RF) signal
processing circuit coupled between a transceiver module and at
least a first antenna and a second antenna comprises a quadrature
power amplifier. The quadrature power amplifier comprises a first
input terminal and a second input terminal coupled to the
transceiver, and a first output terminal coupled to the first
antenna and a second output terminal coupled to the second antenna.
When the quadrature power amplifier receives a first input signal
and a second input signal from the transceiver module respectively
via the first input terminal and the second input terminal, the
quadrature power amplifier splits, and phase-shifts the first input
signal and the second input signal into two first split signals and
two second split signals, respectively, and further amplifies and
combines the two first split signals and the two second split
signals to respectively generate a first output signal, which is an
amplified version of the first input signal with a first
predetermined phase difference, and a second output signal, which
is an amplified version of the second input signal with a second
predetermined phase difference, and outputs the first output signal
to the second antenna and the second output signal to the first
antenna.
[0011] A detailed description is given in the following embodiments
with reference to the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0012] The invention can be more fully understood by reading the
subsequent detailed description and examples with references made
to the accompanying drawings, wherein:
[0013] FIG. 1 shows a simplified block diagram of a communications
apparatus according to an embodiment of the invention;
[0014] FIG. 2 shows a simplified block diagram of a quadrature
power amplifier according to an embodiment of the invention;
[0015] FIG. 3a shows a simplified block diagram of a communications
apparatus operating in TDD system with a quadrature power amplifier
coupled therein according to an embodiment of the invention;
[0016] FIG. 3b shows a simplified block diagram of a communications
apparatus operating in FDD system with a quadrature power amplifier
coupled therein according to another embodiment of the
invention;
[0017] FIG. 4a shows a simplified block diagram of a communications
apparatus operating in TDD system with a quadrature power amplifier
coupled therein according to another embodiment of the
invention;
[0018] FIG. 4b shows a simplified block diagram of a communications
apparatus operating in FDD system with a quadrature power amplifier
coupled therein according to yet another embodiment of the
invention;
[0019] FIG. 5 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the single-output mode according to an embodiment of
the invention;
[0020] FIG. 6 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the single-output mode according to another embodiment
of the invention;
[0021] FIG. 7 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the multiple-output mode according to another
embodiment of the invention; and
[0022] FIG. 8 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the multiple-output mode according to yet another
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The following description is of the best-contemplated mode
of carrying out the invention. This description is made for the
purpose of illustrating the general principles of the invention and
should not be taken in a limiting sense. The scope of the invention
is best determined by reference to the appended claims.
[0024] FIG. 1 shows a simplified block diagram of a communications
apparatus according to an embodiment of the invention. The
communications apparatus 100 may comprise a baseband module 101, a
transceiver module 102, a radio frequency (RF) signal processing
circuit 103 and multiple antennas 104 and 105. The baseband module
101 may comprise multiple hardware devices to perform baseband
signal processing, including Analog to Digital Conversion
(ADC)/Digital to Analog Conversion (DAC), gain adjusting,
modulation/demodulation, encoding/decoding, and so on. The
transceiver module 102 may receive RF signals, convert the received
RF signals to baseband signals, which are processed by the baseband
module 101, or receive baseband signals from the baseband module
101 and convert the received baseband signals to RF signals, which
are later transmitted. The transceiver module 102 may also comprise
multiple hardware devices to perform radio frequency conversion.
For example, the transceiver module 102 may comprise a mixer to
multiply the baseband signals with a carrier oscillated in the
radio frequency of the wireless communications system.
[0025] The RF signal processing circuit 103 may comprise one or
more T/R (transmit/receive) switches for switching the downlink and
uplink paths between the transceiver module 102 and the antennas
104 and 105 when operate in TDD system or may comprise one or more
T/R (transmit/receive) duplexer to separate the downlink and uplink
path signals between transceiver module 102 and the antennas 104
and 105 when operate in FDD system, and one or more power
amplifiers for amplifying the RF signals to be later transmitted to
the air interface or amplifying the RF signals that have been
received from the antennas. According to an embodiment of the
invention, the RF signal processing circuit 103 may further
comprise a quadrature power amplifier, which is capable of
amplifying and outputting one or more signals to the antennas,
depending on whether antenna diversity is required.
[0026] FIG. 2 shows a simplified block diagram of a quadrature
power amplifier according to an embodiment of the invention. The
quadrature power amplifier 200 may comprise quadrature couplers 201
and 202, and power amplifiers 203 and 204. According to an
embodiment of the invention, the quadrature power amplifier 200 is
capable of operating in a single-output mode and a multiple-output
mode. When operating in the single-output mode, the quadrature
power amplifier 200 receives a first input signal from the
transceiver module via one of the input terminals TX1 and TX2, and
generates a first output signal, which is an amplified version of
the first input signal with a predetermined phase difference, at
one of the output terminals ANT1 and ANT2. The first output signal
is then transmitted by one of the antennas 104 and 105 to the air
interface.
[0027] Meanwhile, when operating in the multiple-output mode, the
quadrature power amplifier 200 receives a first input signal and a
second input signal from the transceiver module respectively via
the input terminals TX1 and TX2, and generates a first output
signal at one of the output terminals ANT1 and ANT2 and a second
output signal at the other one of the output terminals ANT1 and
ANT2. The first output signal is an amplified version of the first
input signal with a first predetermined phase difference, and the
second output signal is an amplified version of the second input
signal with a second predetermined phase difference. The first
predetermined phase difference and the second predetermined phase
difference may be the same or different, depending on the phases of
the first and second input signals. The first and second output
signals are then transmitted by the antennas 104 and 105,
respectively.
[0028] FIG. 3a shows a simplified block diagram of a communications
apparatus operating in TDD (Time Division Duplex) system with a
quadrature power amplifier coupled therein according to an
embodiment of the invention. As shown in FIG. 3a, the RF signal
processing circuit 303 may comprise low noise amplifiers 333 and
334 in the downlink paths, a quadrature power amplifier 335 in the
uplink paths and T/R switches 331 and 332. The T/R switches 331 and
332 are arranged to selectively connect the antennas 104 and 105 to
the down link paths or the uplink paths when operate in TDD system.
The low noise amplifiers 333 and 334 in the downlink paths are
arranged to amplify the RF signals that have been received from the
antennas 104 and 105, and the quadrature power amplifier 335 is
arranged to amplify the RF signals to be later transmitted. The
nodes BBRX1 and BBRX2 of the transceiver module 102 are coupled to
the baseband module 101 for transmitting the received downlink
signals thereto, and the nodes BBTX1 and BBTX2 of the transceiver
module 102 are coupled to the baseband module 101 for receiving the
uplink signals to be later transmitted therefrom. In the
embodiment, the quadrature power amplifier 335 is capable of
operating in the single-output mode and the multiple-output mode
(which will be discussed in detail in the following paragraphs).
When operating in the single-output mode, an extra 3 dB output
power in the output signal is gained as compared to the
multiple-output mode.
[0029] FIG. 3b shows a simplified block diagram of a communications
apparatus operating in FDD (Frequency Division Duplex) system with
a quadrature power amplifier coupled therein according to an
embodiment of the invention. As shown in FIG. 3b, the RF signal
processing circuit 303 may comprise low noise amplifiers 333 and
334 in the downlink paths, a quadrature power amplifier 335 in the
uplink paths and duplexers 336 and 337. The duplexers 336 and 337
are arranged to connect the antennas 104 and 105 to the downlink
paths or the uplink paths and separate the downlink signal and
uplink signal when operate in FDD system. The low noise amplifiers
333 and 334 in the downlink paths are arranged to amplify the RF
signals that have been received from the antennas 104 and 105, and
the quadrature power amplifier 335 is arranged to amplify the RF
signals to be later transmitted. In the embodiment, the quadrature
power amplifier 335 is capable of operating in the single-output
mode and the multiple-output mode (which will be discussed in
detail in the following paragraphs). When operating in the
single-output mode, an extra 3 dB output power in the output signal
is gained as compared to the multiple-output mode.
[0030] FIG. 4a shows a simplified block diagram of a communications
apparatus operating in TDD system with a quadrature power amplifier
coupled therein according to another embodiment of the invention.
As shown in FIG. 4a, the RF signal processing circuit 303 may
further comprise a switch 436 coupled between the quadrature power
amplifier 435 and the transceiver module 102. In the embodiment,
the quadrature power amplifier 435 is capable of operating in the
single-output mode, and the switch 436 is arranged to selectively
pass the signal received from the transceiver module 102 to one of
the input terminals TX1 and TX2 in response to an antennal
selection signal S.sub.SEL. The nodes BBRX1 and BBRX2 of the
transceiver module 102 are coupled to the baseband module 101 for
transmitting the received downlink signals thereto, and the node
BBTX of the transceiver module 102 is coupled to the baseband
module 101 for receiving the uplink signals to be later transmitted
therefrom. The antennal selection signal S.sub.SEL may be generated
by the baseband module 101 to indicate which antenna is selected to
transmit the output signal. Thereafter, the amplified output signal
is transmitted to one of the corresponding antennas 104 and
105.
[0031] FIG. 4b shows a simplified block diagram of a communications
apparatus operating in FDD system with a quadrature power amplifier
coupled therein according to another embodiment of the invention.
As shown in FIG. 4b, the RF signal processing circuit 303 may
further comprise a switch 436 coupled between the quadrature power
amplifier 435 and the transceiver module 102. One or more duplexer
as shown to separate the downlink and uplink signal from and to
antennas when operate in FDD system. In the embodiment, the
quadrature power amplifier 435 is capable of operating in the
single-output mode, and the switch 436 is arranged to selectively
pass the signal received from the transceiver module 102 to one of
the input terminals TX1 and TX2 in response to an antennal
selection signal S.sub.SEL. The antennal selection signal S.sub.SEL
may be generated by the baseband module 101 to indicate which
antenna is selected to transmit the output signal. Thereafter, the
amplified output signal is transmitted to one of the corresponding
antennas 104 and 105.
[0032] FIG. 5 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the single-output mode according to an embodiment of
the invention. In the embodiment, the input terminal TX2 is
terminated (for example, terminated when the switch does not
connect the input terminal TX2 to the transceiver module 102).
Therefore, the quadrature power amplifier can only receive signals
from the transceiver module 102 via the input terminal TX1. The
quadrature power amplifier receives the input signal S.sub.1 with
-5 dBm of power and a 0 degree phase (labeled by S.sub.1(-5 dBm,
0.degree. as shown) from the input terminal TX1. The quadrature
coupler 201 splits and phase-shifts the input signal S.sub.1(-5
dBm, 0.degree. into two split signals S.sub.11(-8 dBm, -90.degree.
and S.sub.12(-8 dBm, -180.degree.. Because the input signal S.sub.1
is split, a 3 dB power drop is presented in the split signals.
[0033] The power amplifier 203 having a predetermined gain (for
example, 35 dB) receives and amplifies the split signal S.sub.11(-8
dBm, -90.degree.) to generate an amplified signal S'.sub.11(27 dBm,
-90.degree.). The power amplifier 204 having a predetermined gain
(for example, 35 dB) receives and amplifies another split signals
S.sub.12(-8 dBm, -180.degree.) to generate another amplified signal
S'.sub.12(27 dBm, -180.degree.). The quadrature coupler 202
receives and phase-shifts the amplified signals S'.sub.11(27 dBm,
-90.degree. and S'.sub.12(27 dBm, -180.degree.), so as to generate
the phase-shifted signals S''.sub.11(27 dBm, -180.degree.) and the
S''.sub.12(27 dBm, 0.degree.) at the output terminal ANT1, and
generates the phase-shifted signals S''.sub.11(27 dBm,
-270.degree.) and S''.sub.12(27 dBm, -270.degree.) at the output
terminal ANT2, respectively. Because -180.degree. and 0.degree. are
complementary phases, after the phase-shifted signals S''.sub.11(27
dBm, -180.degree.) and the S''.sub.12(27 dBm, 0.degree.) are
combined at the output terminal ANT1, the amplitude of the combined
signal at the output terminal ANT1 is zero. Meanwhile, because the
phase-shifted signals S''.sub.11(27 dBm, -270.degree.) and
S''.sub.12(27 dBm, -270.degree.) at the output terminal ANT2 have
the same phase, an output signal S'.sub.1(30 dBm, -270.degree.) is
generated after the phase-shifted signals S''.sub.11(27 dBm,
-270.degree.) and S''.sub.12(27 dBm, -270.degree.) are combined at
the output terminal ANT2. Therefore, the output signal S'.sub.1(30
dBm, -270.degree.), which is an amplified version of the input
signal S.sub.1(-5 dBm, 0.degree.) with a predetermined phase
difference, is generated at the output terminal ANT2.
[0034] FIG. 6 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the single-output mode according to another embodiment
of the invention. In the embodiment, the input terminal TX1 is
terminated (for example, terminated when the switch does not
connect the input terminal TX1 to the transceiver module 102).
Therefore, the quadrature power amplifier can only receive signals
from the transceiver module 102 via the input terminal TX2. The
quadrature power amplifier receives the input signal S.sub.2 with
-5 dBm of power and a 0 degree phase (labeled by S.sub.2(-5 dBm,
0.degree.) as shown) from the input terminal TX2. The quadrature
coupler 201 splits and phase-shifts the input signal S.sub.2(-5
dBm, 0.degree.) into two split signals S.sub.21(-8 dBm,
-180.degree.) and S.sub.22(-8 dBm, -90.degree.). Because the input
signal S.sub.2 is split, a 3 dB power drop is presented in the
split signals.
[0035] The power amplifier 203 receives and amplifies the split
signal S.sub.21(-8 dBm, -180.degree.) to generate an amplified
signal S'.sub.21(27 dBm, -180.degree.). The power amplifier 204
receives and amplifies another split signals S.sub.22(-8 dBm,
-90.degree.) to generate another amplified signal S'22(27 dBm,
-90.degree.). The quadrature coupler 202 receives and phase-shifts
the amplified signals S'.sub.21(27 dBm, -180.degree. and
S'.sub.22(27 dBm, -90.degree.), so as to generate the phase-shifted
signals S''.sub.21(27 dBm, -270.degree.) and the S''.sub.22(27 dBm,
-270.degree.) at the output terminal ANT1, and generates the
phase-shifted signals S''.sub.21(27 dBm, 0.degree.) and S''.sub.22
(27 dBm, -180.degree.) at the output terminal ANT2, respectively.
Similarly, because -180.degree. and 0.degree. are complementary
phases, the amplitude of the combined signal at the output terminal
ANT2 is zero after the phase-shifted signals S''.sub.21(27 dBm,
0.degree.) and S''.sub.22 (27 dBm, -180.degree.) are combined at
the output terminal ANT2. Meanwhile, because the phase-shifted
signals S''.sub.21(27 dBm, -270.degree.) and the S''.sub.22(27 dBm,
-270.degree.) at the output terminal ANT1 have the same phase, an
output signal S'.sub.2(30 dBm, -270.degree.) is generated after the
phase-shifted signals S''.sub.21(27 dBm, -270.degree.) and the
S''.sub.22(27 dBm, -270.degree.) are combined at the output
terminal ANT1. Therefore, the output signal S'.sub.2(30 dBm,
-270.degree.), which is an amplified version of the input signal
S.sub.2(-5 dBm, 0.degree.) with a predetermined phase difference,
is generated at the output terminal ANT1.
[0036] FIG. 7 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the multiple-output mode according to another
embodiment of the invention. In the embodiment, the quadrature
power amplifier receives the input signal S.sub.1(-8 dBm,
0.degree.) from the input terminal TX1 and the input signal
S.sub.2(-8 dBm, 0.degree.) from the input terminal TX2. The
quadrature coupler 201 splits and phase-shifts the input signal
S.sub.1(-8 dBm, 0.degree.) into two split signals S.sub.11(-11 dBm,
-90.degree.) and S.sub.12(-11 dBm, -180.degree.), and splits and
phase-shifts the input signal S.sub.2(-8 dBm, 0.degree.) into two
split signals S.sub.21(-11 dBm, -180.degree.) and S.sub.22(-11 dBm,
-90.degree.), respectively.
[0037] The power amplifier 203 receives and amplifies the split
signals S.sub.11(-11 dBm, -90.degree.) and S.sub.21(-11 dBm,
-180.degree.) to generate the amplified signals S'.sub.11(24 dBm,
-90.degree.) and S'.sub.21(24 dBm, -180.degree.). Similarly, the
power amplifier 204 receives and amplifies the split signals
S.sub.12(-11 dBm, -180.degree.) and S.sub.22(-11 dBm, -90.degree.)
to generate the amplified signals S'.sub.12(24 dBm, -180.degree.)
and 5'.sub.22(24 dBm, -90.degree.). The quadrature coupler 202
receives and phase-shifts the amplified signals S'.sub.11(24 dBm,
-90.degree.) and S'.sub.21(24 dBm, -180.degree.), so as to generate
the phase-shifted signals S''.sub.11(24 dBm, -180.degree.) and the
S''.sub.21(24 dBm, -270.degree.) at the output terminal ANT1 and
generates the phase-shifted signals S''.sub.11(24 dBm,
-270.degree.) and the S''.sub.21(24 dBm, 0.degree.) at the output
terminal ANT2.
[0038] The quadrature coupler 202 further receives and phase-shifts
the amplified signals S'12(24 dBm, -180.degree.) and S'.sub.22(24
dBm, -90.degree.) and generates the phase-shifted signals
S''.sub.12 (24 dBm, 0.degree.) and S''.sub.22(24 dBm, -270.degree.)
at the output terminal ANT1, and generates the phase-shifted
signals S''.sub.12 (24 dBm, -270.degree.) and S''.sub.22(24 dBm,
-180.degree.) at the output terminal ANT2. Because the
phase-shifted signals S''.sub.21(24 dBm, -270.degree.) and the
S''.sub.22(24 dBm, -270.degree.) at the output terminal ANT1 have
the same phase, they are combined as an output signal S'2(27 dBm,
-270.degree.) at the output terminal ANT1. Similarly, because the
phase-shifted signals S''.sub.11 (24 dBm, -270.degree.) and
S''.sub.12(24 dBm, -270.degree.) at the output terminal ANT2 have
the same phase, they are combined as an output signal S'.sub.1(27
dBm, -270.degree.) at the output terminal ANT2. Note that the
remaining phase-shifted signals at the output terminals ANT1 and
ANT2 are cancelled due to being complementary phases. Therefore,
the output signal S'.sub.1(27 dBm, -270.degree.), which is an
amplified version of the input signal S.sub.1(-8 dBm, 0.degree.)
with a predetermined phase difference, and S'.sub.2(27 dBm,
-270.degree.), which is an amplified version of the input signal
S.sub.2(-8 dBm, 0.degree.) with a predetermined phase difference
are finally generated at the output terminals. Note that in the
embodiment, the input signals S.sub.1 and S.sub.2 have
substantially the same phase, and the output signals S'.sub.1 and
S'.sub.2 have substantially the same phase.
[0039] FIG. 8 is a schematic diagram showing the power and phases
of the signals generated by the quadrature power amplifier when
operating in the multiple-output mode according to yet another
embodiment of the invention. In the embodiment, the quadrature
power amplifier receives the input signal S.sub.1(-8 dBm,
0.degree.) from the input terminal TX1 and the input signal
S.sub.2(-8 dBm, -180.degree.) from the input terminal TX2. Note
that the input signals S.sub.1 and S.sub.2 have different phases.
The quadrature coupler 201 splits and phase-shifts the input signal
S.sub.1(-8 dBm, 0.degree.) into two split signals S.sub.11(-11 dBm,
-90.degree.) and S.sub.12(-11 dBm, -180.degree.), and splits and
phase-shifts the input signal S.sub.2(-8 dBm, -180.degree.) into
two split signals S.sub.21(-11 dBm, 0.degree.) and S.sub.22(-11
dBm, -270.degree.), respectively.
[0040] The power amplifier 203 receives and amplifies the split
signals S.sub.11(-11 dBm, -90.degree.) and S.sub.21(-11 dBm,
0.degree.) to generate the amplified signals S'.sub.11(24 dBm,
-90.degree.) and S'.sub.21(24 dBm, 0.degree.). Similarly, the power
amplifier 204 receives and amplifies the split signals S.sub.12(-11
dBm, -180.degree.) and S.sub.22(-11 dBm, -270.degree.) to generate
the amplified signals S'.sub.12(24 dBm, -180.degree.) and
S'.sub.22(24 dBm, -270.degree.). The quadrature coupler 202
receives and phase-shifts the amplified signals S'.sub.11(24 dBm,
-90.degree.) and S'.sub.21(24 dBm, 0.degree.), so as to generate
the phase-shifted signals S''.sub.11(24 dBm, -180.degree.) and the
S''.sub.21(24 dBm, -90.degree.) at the output terminal ANT1 and
generates the phase-shifted signals S''.sub.11(24 dBm,
-270.degree.) and the S''.sub.21(24 dBm, -180.degree.) at the
output terminal ANT2.
[0041] The quadrature coupler 202 further receives and phase-shifts
the amplified signals S'.sub.12(24 dBm, -180.degree.) and
S'.sub.22(24 dBm, -270.degree.) and generates the phase-shifted
signals S''.sub.12 (24 dBm, 0.degree.) and S''.sub.22(24 dBm,
-90.degree.) at the output terminal ANT1, and generates the
phase-shifted signals S''.sub.12 (24 dBm, -270.degree.) and
S''.sub.22(24 dBm, 0.degree.) at the output terminal ANT2. Because
the phase-shifted signals S''.sub.21(24 dBm, -90.degree.) and the
S''.sub.22(24 dBm, -90.degree.) at the output terminal ANT1 have
the same phase, they are combined as an output signal S'.sub.2(27
dBm, -90.degree.) at the output terminal ANT1. Similarly, because
the phase-shifted signals S''.sub.11 (24 dBm, -270.degree.) and
S''.sub.12(24 dBm, -270.degree.) at the output terminal ANT2 have
the same phase, they are combined as an output signal S'.sub.1(27
dBm, -270.degree.) at the output terminal ANT2. Note that the
remaining phase-shifted signals at the output terminals ANT1 and
ANT2 are cancelled due to being complementary phases. Therefore,
the output signal S'.sub.1(2'7 dBm, -270.degree.), which is an
amplified version of the input signal S.sub.1(-8 dBm, 0.degree.)
with a first predetermined phase difference, and S'.sub.2(27 dBm,
-90.degree.), which is an amplified version of the input signal
S.sub.2(-8 dBm, -180.degree.) with a second predetermined phase
difference are finally generated at the output terminals. Note that
in the embodiment, the input signals S.sub.1 and S.sub.2 have
different phases, and the output signals S'.sub.1 and S'.sub.2 have
different phases. Note also that in the embodiment, the first
predetermined phase difference is different from the second
predetermined phase difference.
[0042] By using the quadrature couplers, the output of two power
amplifiers can be automatically combined and thus, higher power can
be output. When operating in the single-output mode, an extra 3 dB
output power in the output signal is gained as compared to the
multiple-output mode. In addition, because the proposed quadrature
power amplifier is capable of operating in a single-output mode and
a multiple-output mode, the proposed architecture may be applied in
either the single-input-single-output (SISO) system or the
multiple-input-multiple-output (MIMO) system, such as the single
antenna system, the intelligent transmit antenna selection (i-TAS)
system, the MIMO matrix A system, the MIMO matrix B system, the
cyclic delay diversity system (CCD), and the likes. When operating
in the multiple-output mode, benefits of using antenna diversity
can be gained. The operation modes is activated according to the
demand from the baseband to combat with the variation on the uplink
channel conditions to achieve the performance target such as
coverage, throughput, efficiency etc.
[0043] Use of ordinal terms such as "first", "second", "third",
etc., in the claims to modify a claim element does not by itself
connote any priority, precedence, or order of one claim element
over another or the temporal order in which acts of a method are
performed, but are used merely as labels to distinguish one claim
element having a certain name from another element having a same
name (but for use of the ordinal term) to distinguish the claim
elements.
[0044] While the invention has been described by way of example and
in terms of preferred embodiment, it is to be understood that the
invention is not limited thereto. Those who are skilled in this
technology can still make various alterations and modifications
without departing from the scope and spirit of this invention.
Therefore, the scope of the present invention shall be defined and
protected by the following claims and their equivalents.
* * * * *