Leakage power reduction apparatus

• US 8,086,191 B2
• Filed: 05/02/2008
• Issued: 12/27/2011
• Est. Priority Date: 05/07/2007
• Status: Expired due to Fees

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Fukuda, Atsushi, Okazaki, Hiroshi, Narahashi, Shoichi
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US12/114,218
• Publication Number:
  US 20080279122A1
• Time in Patent Office: 1,334 Days
• Field of Search: 455/73, 455/78, 455/82, 455/83, 455/296, 455/303, 455/304, 455/305, 455/306, 455/307, 455/114.2
• US Class Current: 455/114.2
• CPC Class Codes: H04B 1/525 with means for reducing leakage of transmitter signal into the receiver

Abstract

A circulator extracts a transmission signal sent from a transmitter to antenna via the circulator and a duplexer, reflected by an antenna, and returned via the duplexer to the transmitter side. The amplitude and phase of the extracted signal are adjusted by an amplitude-and-phase adjuster to generate an offset signal having the same amplitude and the opposite phase with respect to a leaking transmission signal included in a signal output from a third terminal of the duplexer when combined by a combiner. The offset signal is combined in the combiner with the leaking transmission signal included in the signal output from the third terminal of the duplexer to suppress the leaking transmission signal.

Claims

1. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a reception band-pass filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate components outside the reception frequency band; and

a terminator which is connected to the other end of the reception band-pass filter and is configured to absorb a signal input thereto.

5. The leakage power reduction apparatus according to any one of claim 1 to 4, further comprising a delay device which is inserted between the third terminal of the duplexer and the combiner and is configured to adjust the amount of delay of the output signal sent from the third terminal of the duplexer.

6. The leakage power reduction apparatus according to any one of claim 1 to 4, further comprising a phase shifter which is connected between the second terminal of the duplexer and the antenna and is configured to adjust the amount of phase shift of a signal input thereto.

7. The leakage power reduction apparatus according to any one of claim 1 to 4, wherein the amplitude-and-phase adjuster comprises an attenuator for adjusting the amplitude of an input signal and a phase shifter for adjusting the amount of phase shift of a signal input from the attenuator.

8. The leakage power reduction apparatus according to any one of claim 1 to 4, wherein the amplitude-and-phase adjuster comprises:

a divider for dividing the signal from the third port of the circulator into two parts;

first attenuation means which is configured to receive one of the two parts of the signal divided by the divider, adjust the amplitude thereof, and output a signal;

first phase shift means which is configured to adjust the amount of phase shift of the signal output from the first attenuation means and output a signal;

second attenuation means which is configured to receive the other part of the two parts of the signal divided by the divider, adjust the amplitude thereof, and output a signal;

second phase shift means which is configured to adjust the amount of phase shift of the signal output from the second attenuation means and outputs a signal; and

combining means which is configured to combine the signal output from the first phase shift means and the signal output from the second phase shift means, and output a combined signal as the offset signal for the transmission frequency band.

9. The leakage power reduction apparatus according to claim 8, further comprising a third phase shift means inserted between the antenna and the second terminal of the duplexer, said third phase shift means being set such that a first reception frequency band component of the transmission signal leaked from the second terminal to the third terminal of the duplexer and a second reception frequency band component of the transmission signal leaked from the first terminal directly to the third terminal of the duplexer are in phase with each other at the output of the third terminal of the duplexer.

2. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a transmission band-elimination filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate the transmission frequency band component; and

a terminator which is connected to the other end of the transmission band-elimination filter and is configured to absorb a signal input thereto.

3. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a reception band-pass filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate components outside the reception frequency band;

an attenuator which has one end connected to the other end of the reception band-pass filter and is configured to adjust the amplitude of a signal input thereto; and

a reflector which is connected to the other end of the attenuator, and is configured to reflect an output signal of the attenuator and output an offset signal for the reception frequency band;

the offset signal for the reception frequency band being supplied to the combiner through the attenuator, the reception band-pass filter, the circulator, and the amplitude-and-phase adjuster to suppress a reception frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer.

4. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a transmission band-elimination filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate the transmission frequency band component;

an attenuator which has one end connected to the other end of the transmission band-elimination filter and is configured to adjust the amplitude of a signal input thereto; and

a reflector which is connected to the other end of the attenuator and is configured to reflect an output signal of the attenuator and output an offset signal for the reception frequency band;

the offset signal for the reception frequency band being provided to the combiner through the attenuator, the transmission band-elimination filter, the circulator, and the amplitude-phase shifter to suppress a reception frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer.

10. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a reception band-pass filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate components outside the reception frequency band; and

an additional amplitude-and-phase adjuster which is connected to the other end of the reception band-pass filter and is configured to adjust the amplitude and phase of an output signal from the reception band-pass filter to generate an offset signal for the reception frequency band and provide the offset signal for the reception frequency band to the combiner;

wherein the combiner is configured to suppress a reception frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer, by using the offset signal for the reception frequency band.

11. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a transmission band-elimination filter which has one end connected between the second port of the circulator and the first terminal of the duplexer and is configured to attenuate the transmission frequency band component; and

an additional amplitude-and-phase adjuster which is connected to the other end of the transmission band-elimination filter and is configured to adjust the amplitude and phase of an output signal from the transmission band-elimination filter to generate an offset signal for the reception frequency band and provide the offset signal for the reception frequency band to the combiner;

wherein the combiner is configured to suppress a reception frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer, by using the offset signal for the reception frequency band.

12. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band;

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

a signal separator which comprises a first terminal, a second terminal connected to the third port of the circulator and a third terminal, and is configured to separate the signal output from the third port of the circulator into a transmission frequency band component and a reception frequency band component of the transmission signal, and output the components to the first terminal and the third terminal, respectively, one end of the amplitude-and-phase adjuster being connected to the first terminal of the signal separator, thereby being connected to the third port of the circulator through the signal separator; and

an additional amplitude-and-phase adjuster which has one end connected to the third terminal of the signal separator, and is configured to adjust the amplitude and phase of an output signal from the third terminal of the signal separator to generate an offset signal for the reception frequency band, and provide the offset signal for the reception frequency band to the combiner;

wherein the combiner is configured to suppress a reception frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer, by using the offset signal for the reception frequency band.

13. The leakage power reduction apparatus according to claim 12, further comprising a signal combining means which is configured to combine the offset signal for the transmission frequency band and the offset signal for the reception frequency band sent from the amplitude-and-phase adjuster and the additional amplitude-and-phase adjuster and provide a combined signal to the combiner.

14. The leakage power reduction apparatus according to claim 12, wherein the signal separator is configured to allow a signal in the transmission frequency band to pass through and suppress a signal in the reception frequency band between the first terminal and the second terminal, allow a signal in the reception frequency band to pass through and suppress a signal in the transmission frequency band between the second terminal and the third terminal, and suppress a signal in the transmission frequency band and a signal in the reception frequency band between the first terminal and the third terminal.

15. A leakage power reduction apparatus for suppressing a leaking transmission signal leaking from a transmitter side to a receiver side, directly or through reflection by an antenna, the apparatus comprising:

a circulator which comprises a first port, a second port, and a third port, outputs a transmission signal input from the first port to the second port, and outputs a signal input from the second port to the third port;

a duplexer which comprises a first terminal, a second terminal, and a third terminal, the first and the second terminals being connected to the second port of the circulator and the antenna, respectively, said duplexer being configured such that a signal in a transmission frequency band is allowed to pass and a signal in a reception frequency band is suppressed between the first terminal and the second terminal, a signal in the reception frequency band being allowed to pass and a signal in the transmission frequency band is suppressed between the second terminal and the third terminal, and signals in the transmission frequency band and the reception frequency band both are suppressed between the first terminal and the third terminal;

an amplitude-and-phase adjuster which is connected to the third port of the circulator and is configured to adjust the amplitude and phase of the signal input from the circulator, and output the adjusted signal as an offset signal for the transmission frequency band; and

a combiner which is configured to receive an output signal sent from the third terminal of the duplexer and the offset signal for the transmission frequency band sent from the amplitude-and-phase adjuster, and output a signal obtained by suppressing a transmission frequency band component of the leaking transmission signal included in the output signal sent from the third terminal of the duplexer by the offset signal for the transmission frequency band;

wherein the amplitude-and-phase adjuster comprises;

a divider for dividing the signal from the third port of the circulator into two parts;

first attenuation means which is configured to receive one of the two parts of the signal divided by the divider, adjust the amplitude thereof, and output a signal;

first phase shift means which is configured to adjust the amount of phase shift of the signal output from the first attenuation means and output a signal;

second attenuation means which is configured to receive the other part of the two parts of the signal divided by the divider, adjust the amplitude thereof, and output a signal;

second phase shift means which is configured to adjust the amount of phase shift of the signal output from the second attenuation means and outputs a signal; and

combining means which is configured to combine the signal output from the first phase shift means and the signal output from the second phase shift means, and output a combined signal as the offset signal for the transmission frequency band; and

wherein the leakage power reduction apparatus further comprising;

a third phase shift means inserted between the antenna and the second terminal of the duplexer, said third phase shift means being set such that a first reception frequency band component of the transmission signal leaked from the second terminal to the third terminal of the duplexer and a second reception frequency band component of the transmission signal leaked from the first terminal directly to the third terminal of the duplexer are in phase with each other at the output of the third terminal of the duplexer.