System for transmitting/receiving a signal having a carrier frequency band for a radio base station

• US 6,233,434 B1
• Filed: 02/25/1999
• Issued: 05/15/2001
• Est. Priority Date: 08/28/1998
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takei, Ken
• Primary Examiner(s): Maung, May
• Application Number:
  US09/257,050
• Time in Patent Office: 810 Days
• Field of Search: 455/84, 455/91, 455/103, 455/114, 455/115, 455/116, 455/126, 455/127, 455/561, 455/562, 330/124.R, 330/295
• US Class Current: 455/103
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H01Q 3/30 varying the relative phase between the radiating elements of an array H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence
• CPC Class Codes: H03F 1/3223 using feed-forward H03F1/3211 takes precedence
• CPC Class Codes: H03F 1/3229 using a loop for error extraction and another loop for error subtraction
• CPC Class Codes: H03F 2200/372 Noise reduction and elimination in amplifier
• CPC Class Codes: H03F 2201/3218 the main amplifier or error amplifier being a feedforward amplifier
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H03F 3/602 Combinations of several amplifiers
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 2001/0441 with linearisation using feed-forward

Abstract

In a system for feeding electric power having a carrier band for a mobile communication base station including transmission power amplifiers and an array antenna, a transmission/reception system is capable of reducing a large loss which the transmission electric power suffers until the transmission electric power having a large output has been radiated into the air, and increase in the power consumption. The system includes a plurality of transmission/reception signal amplifying devices, which are respectively coupled to a plurality of antennas, in each of which a feed forward power amplifier which is realized with less electric power than the total electric power which is to be radiated from the associated antenna into the air, and a low noise amplifier are respectively coupled to the associated antennas through a transmission filter and a reception filter, wherein an output of a power detector connected to an output portion of the feed forward power amplifier is compared with a control signal of a tilt angle control circuit to adjust, every feed forward amplifier, the phase shift amount of a variable phase shift circuit inserted into an output portion of the feed forward power amplifier while referring to a phase shift amount table which is constructed on the basis of the characteristics of the feed forward circuit.

Claims

1. A system for transmitting/receiving an electrical signal, said system comprising:

a plurality of transmission/reception signal amplifying devices each having a power amplifier, a variable phase shift circuit connected to an input portion of said power amplifier, a power detector connected to an output portion of said power amplifier, and a phase shifting amount table which is constructed on the basis of the characteristics of said power amplifier;

a plurality of antennas which are respectively connected to said transmission/reception signal amplifying devices; and

a tilt angle control circuit which is connected to said transmission/reception signal amplifying devices,

wherein each of the outputs of said power detectors is compared with a control signal of said tilt angle control circuit to adjust the phase shifting amount of said variable phase shifting circuits on the basis of the contents of said phase shifting amount table.

2. A transmission/reception system according to claim 1, wherein said power amplifier is a feed forward power amplifier.

3. A transmission/reception system according to claim 1, wherein said antennas are microstrip antennas.

4. A transmission/reception system according to claim 1, wherein said antennas are slot antennas.

5. A system for transmitting/receiving an electrical signal, wherein a plurality of units each having an antenna and a transmission/reception signal amplifying device connected to said antenna are provided, and each of said plurality of units has a variable phase shift circuit connected to an input terminal for transmission of a transmission electric power amplifier, said circuit serving to take charge of the transmission electric power which is obtained by dividing the total electric power which is to be radiated from all of said antennas into the air.

6. A system for transmitting/receiving a signal having a carrier frequency band for a radio base station, said system comprising:

a plurality of automatic phase shift control feed forward transmission/reception units installed in parallel with one another, each unit comprising;

a first amplifier, a first variable phase shifter and variable attenuator, a first splitter, a first delay line, a first combiner;

a second amplifier, a second splitter, a second variable phase shifter and variable attenuator, a second splitter, a second delay line, a second combiner;

a third amplifier, a third splitter, a third variable phase shifter and variable attenuator, a third delay line, a third combiner;

a fourth splitter, a fourth variable phase shifter and variable attenuator, a fourth delay line, a fourth combiner;

a fifth splitter, an attenuator, a fifth delay line, a sixth splitter, a fifth combiner, a signal detector, a table reference circuit, a comparison circuit, a variable phase shifter, a signal control circuit, a transmission filter, a reception filter, a branch circuit, a fourth amplifier, and a first antenna, wherein an input signal terminal of said variable phase shifter is coupled to a transmission signal input terminal;

subsequently, said sixth splitter is coupled thereto;

an input terminal of said third splitter is coupled to a first output terminal of said sixth splitter;

an input terminal of said first splitter is coupled to a first output terminal of said third splitter through said third variable phase shifter and variable attenuator;

an input terminal of said first amplifier is coupled to a first output terminal of said first splitter through said first variable phase shifter and variable attenuator;

an input terminal of said second splitter is coupled to an output terminal of said first amplifier;

a first input terminal of said second combiner is coupled to a first output terminal of said second splitter through said second delay line;

an output terminal of said second combiner is coupled to a first input terminal of said fourth splitter;

an output terminal of said fourth splitter is coupled to a first input terminal of said fourth combiner through said fourth delay line;

an output terminal of said fourth combiner is coupled to an input terminal of said fifth splitter;

a first output terminal of said fifth splitter is coupled to one branch of said branch circuit through said transmission filter;

said first antenna is coupled to a common branch of said branch circuit;

an input terminal of said fourth amplifier is coupled to the other branch of said branch circuit through said reception filter;

a reception signal output terminal is coupled to an output terminal of said fourth amplifier;

said fifth delay line is coupled to a second output terminal of said fifth splitter through said attenuator;

subsequently, a first input terminal of said fifth combiner is coupled thereto;

a second output terminal of said sixth splitter is coupled to a second input terminal of said fifth combiner;

an output terminal of said fifth combiner is coupled to an input terminal of said table reference circuit through said signal detection circuit;

an output terminal of said table reference circuit is coupled to a first input terminal of said comparison circuit;

a second input terminal of said comparison circuit is a control signal input terminal of a tilt angle control circuit;

an output terminal of said third amplifier is coupled to a second input terminal of said fourth combiner;

an output terminal of said third combiner is coupled to an input terminal of said third amplifier through said fourth variable phase shifter and variable attenuator;

a second output terminal of said fourth splitter is coupled to a second input terminal of said third combiner;

a second output terminal of said third splitter is coupled to a first input terminal of said third combiner through said third delay line;

an output terminal of said second amplifier is coupled to a second input terminal of said second combiner;

an output terminal of said first combiner is coupled to an input terminal of said second amplifier through said second variable phase shifter and variable attenuator;

a second output terminal of said second splitter is coupled to a second input terminal of said first combiner; and

a second output terminal of said first splitter is coupled to a first input terminal of said first combiner through said first delay line, and

a control circuit for referring to an output signal of said second combiner, an output signal of said fourth combiner, an output signal of said first combiner, and an output signal of said third combiner to control the phase/attenuation amount of said second variable phase shifter and variable attenuator, said fourth variable phase shifter and variable attenuator, said first variable phase shifter and variable attenuator and said third variable phase shifter and variable attenuator, and

said one tilt angle control circuit for supplying a control signal to each of the control signal input terminals of said tilt angle control circuit of said plurality of automatic phase shift control feed forward transmission/reception units.

7. A system for transmitting/receiving a signal having a carrier frequency band for a radio base station, said system comprising:

a plurality of automatic phase shift control transmission/reception signal amplifying units installed in parallel with one another, each unit comprising a linear power amplifier, a fifth splitter, an attenuator, a fifth delay line, a sixth splitter, a fifth combiner, a signal detector, a table reference circuit, a comparison circuit, a variable phase shifter, a signal control circuit, a transmission filter, a reception filter, a branch circuit, a fourth amplifier and a first antenna, wherein an input signal terminal of said variable phase shifter is coupled to a transmission signal input terminal;

subsequently, said sixth splitter is coupled thereto;

an input terminal of said linear power amplifier is coupled to a first output terminal of said sixth splitter;

an output terminal of said linear power amplifier is coupled to an input terminal of said fifth splitter;

a first output terminal of said fifth splitter is coupled to one branch of said branch circuit through said transmission filter;

said first antenna is coupled to a common branch of said branch circuit;

an input terminal of said fourth amplifier is coupled to the other branch of said branch circuit;

a reception signal output terminal is coupled to an output terminal of said fourth amplifier;

said fifth delay line is coupled to a second output terminal of said fifth splitter through said attenuator;

subsequently, a first input terminal of said fifth combiner is coupled thereto;

a second input terminal of said fifth signal combiner is coupled to a second output terminal of said sixth splitter;

an output terminal of said fifth combiner is coupled to an input terminal of said table reference circuit through said signal detection circuit;

an output terminal of said table reference circuit is coupled to a first input terminal of said comparison circuit; and

a second input terminal of said comparison circuit is a control signal input terminal of one tile angle control circuit, and

said one tilt angle control circuit for supplying a control signal to each of the control signal input terminals of said tilt angle control circuit of said plurality of automatic phase shift transmission/reception signal amplifying units.

8. A system according to claim 7, wherein said linear power amplifier is a feed forward type amplifier.

9. A system according to claim 8, wherein said automatic phase shift control feed forward transmission/reception unit includes a second antenna, a fifth amplifier and a second reception filter;

said unit includes a second reception signal output terminal;

an output terminal of said fifth amplifier is coupled to the second reception signal output terminal; and

said second antenna is coupled to an input terminal of said fifth amplifier through said reception filter, thereby making the diversity reception possible.

10. A system according to claim 9, wherein an array constituted by the antenna which is coupled to the common branch of said branch circuit of said automatic phase shift control feed forward transmission/reception unit and the second antenna which is coupled to said second reception filter is an array of a microstrip antenna as said first antenna and a slot antenna as said second antenna which are formed in the same plane and which are formed on the earth plate having the electric potential electrically common thereto;

with respect to the element antennas of the microstrip antennas and the slot antennas constituting the array antenna, for the microstrip antennas, the resonance direction of those antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed, while for the slot antennas, the longitudinal direction as the resonance direction of the slots, or the longitudinal direction of the center portions when viewed along the direction of formation of the slots in the case where the slots are bent in shape at the ends thereof matches the longitudinal direction of the array, i.e., the direction along which the array is formed;

the resonance direction of the slot antennas and the longitudinal direction of the slot center portions of the slot antennas are disposed approximately in the same straight line in all of the antennas constituting the array; and

the microstrip antennas and the slot antennas are alternately arranged.

11. A system according to claim 9, wherein an array constituted by the antenna which is coupled to the common branch of said branch circuit of said automatic phase shift control feed forward transmission/reception unit and the second antenna which is coupled to said second reception filter is an array of a slot antenna as said first antenna and a microstrip antenna as said second antenna which are formed in the same plane and which are formed on the earth plate having the electric potential electrically common thereto;

with respect to the element antennas of the microstrip antennas and the slot antennas constituting the array antenna, for the microstrip antennas, the resonance direction of those antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed, while for the slot antennas, the longitudinal direction as the resonance direction of the slots, or the longitudinal direction of the center portions when viewed along the direction of formation of the slots in the case where the slots are bent in shape at the ends thereof matches the longitudinal direction of the array, i.e., the direction along which the array is formed;

the resonance direction of the slot antennas and the longitudinal direction of the slot center portions of the slot antennas are disposed approximately in the same straight line in all of the antennas constituting the array; and

the microstrip antennas and the slot antennas are alternately arranged.

12. A system according to claim 8, wherein a part of or all of said first to fifth delay lines which said automatic phase shift control feed forward transmission/reception unit includes is/are replaced with a delay filter or delay filters.

13. A system according to claim 8, wherein said third combiner, said third splitter, said third variable phase shifter and variable attenuator, said fourth combiner, said fourth splitter, and said fourth variable phase shifter and variable attenuator are all removed, and the output terminal of said second combiner and the input terminal of said first splitter are directly coupled to the input terminal of said first splitter and the second input terminal of said sixth splitter, respectively.

14. A system according to claim 8, wherein said antennas which are coupled to the common branches of said branch circuits of said automatic phase shift control feed forward transmission/reception units constitute an array antenna.

15. A system according to claim 8, wherein said antennas which are coupled to the common branches of said branch circuits of said automatic phase shift control feed forward transmission/reception units constitute an array of microstrip antennas which are formed in the same plane and which are formed on the earth plate having the electric potential electrically common thereto;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line.

16. A system according to claim 15, wherein the size of the longitudinal direction matching the array direction of the element antennas is approximately half the wavelength of the carrier.

17. A system according to claim 8, wherein an array constituted by the antennas which are coupled to the common branches of said branch circuits of said automatic phase shift control feed forward transmission/reception units is an array of printed dipole antennas which are formed in the same plane and which are formed on a dielectric or a ceramic substrate;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line.

18. A system according to claim 8, wherein an array constituted by the antennas which are coupled to the common branches of said branch circuits of said automatic phase shift control feed forward transmission/reception units is an array of slot antennas which are formed in the same plane and which are formed on a dielectric or a ceramic substrate;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line.

19. A system according to claim 7, wherein said automatic phase shift control feed forward transmission/reception unit includes a second antenna;

said branch circuit is removed;

said first antenna is directly coupled to the output terminal of said transmission filter; and

said second antenna is directly coupled to an input terminal of said reception filter.

20. A system according to claim 19, wherein said automatic phase shift control feed forward transmission/reception unit includes a second antenna, a fifth amplifier, and a second reception filter;

said unit includes a second reception signal output terminal;

an output terminal of said fifth amplifier is coupled to the second reception signal output terminal; and

said second antenna is coupled to an input terminal of said fifth amplifier through said reception filter, thereby making the diversity reception possible.

21. A system according to claim 20, wherein an array constituted by said first antenna which is coupled to said transmission filter of said automatic phase shift control feed forward transmission/reception unit, said second antenna which is coupled to said first reception filter, and said third antenna which is coupled to said second reception filter is an array of microstrip antennas and slot antennas which are formed in the same plane and which are formed on the earth plate having an electric potential electrically common thereto;

said first antenna and said second antennas are microstrip antennas, and said third antenna is the slot antenna;

with respect to the element antennas of the microstrip antennas and the slot antennas constituting the array antenna, for the microstrip antennas, the resonance direction of those antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed, while for the slot antennas, the longitudinal direction as the resonance direction of the slots, or the longitudinal direction of the center portions when viewed along the direction of formation of the slots in the case where the slots are bent in shape at the ends thereof matches the longitudinal direction of the array, i.e., the direction along which the array is formed;

said third antenna and said second antenna are arranged in parallel in such a way that the longitudinal direction of the slot center portion is parallel with the resonance direction thereof;

the parallel arrangements of said second antenna and said third antenna, and said first antennas are disposed alternately; and

the center line extending along the resonance direction of said first antenna, and the line segment which lies half-way between the center line extending along the resonance direction of the second antenna and the line segment the extending direction of which matches the longitudinal direction of the slot center portion of said third antenna, and which extends in the same direction as that of the center line and the line segment are disposed approximately in the same straight line.

22. A system according to claim 20, wherein an array constituted by said first antenna which is coupled to said transmission filter of said automatic phase shift control feed forward transmission/reception unit, said second antenna which is coupled to said first reception filter, and said third antenna which is coupled to said second reception filter is an array of slot antennas and microstrip antennas which are formed in the same plane and which are formed on the earth plate having an electric potential electrically common thereto;

said first antenna and said second antennas are slot antennas, and said third antenna is the microstrip antenna;

with respect to the element antennas of the microstrip antennas and the slot antennas constituting the array antenna, for the microstrip antennas, the resonance direction of those antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed, while for the slot antennas, the longitudinal direction as the resonance direction of the slots, or the longitudinal direction of the center portions when viewed along the direction of formation of the slots in the case where the slots are bent in shape at the ends thereof matches the longitudinal direction of the array, i.e., the direction along which the array is formed;

said third antenna and said second antenna are arranged in parallel in such a way that the longitudinal direction of the slot center portion is parallel with the resonance direction thereof;

the parallel arrangements of said second antenna and said third antenna, and said first antennas are disposed alternately; and

the center line extending along the resonance direction of said first antenna, and the line segment which lies half-way between the center line extending along the resonance direction of the second antenna and the line segment the extending direction of which matches the longitudinal direction of the slot center portion of said third antenna, and which extends in the same direction as that of the center line and the line segment are disposed approximately in the same straight line.

23. A system according to claim 19, wherein an array constituted by said first antenna which is coupled to said transmission filter of said automatic phase shift control feed forward transmission/reception unit and said second antenna which is coupled to said reception antenna is an array of microstrip antennas which are formed in the same plane and which are formed on a dielectric or a ceramic substrate;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line; and

the antennas coupled to said transmission filters and the antennas coupled to said reception filters are alternately arranged.

24. A system according to claim 19, wherein an array constituted by said first antenna which is coupled to said transmission filter of said automatic phase shift control feed forward transmission/reception unit and said second antenna which is coupled to said reception filter is an array of printed dipole antennas which are formed in the same plane and which are formed on a dielectric or a ceramic substrate;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line; and

the antennas coupled to said transmission filters and the antennas coupled to said reception filters are alternately arranged.

25. A system according to claim 19, wherein an array constituted by said first antenna which is coupled to said transmission filter of said automatic phase shift control feed forward transmission/reception unit and said second antenna which is coupled to said reception filter is an array of slot antennas which are formed in the same plane and which are formed on a dielectric or a ceramic substrate;

for the element antennas constituting the array antenna, the resonance direction of the element antennas matches the longitudinal direction of the array, i.e., the direction along which the array is formed; and

the center lines of all of the antennas constituting the array which match the resonance direction of the element antennas are formed in the same straight line; and

the antennas coupled to said transmission filters and the antennas coupled to said reception filters are alternately arranged.

26. A system for transmitting an electrical signal, comprising:

a plurality of transmission signal amplifiers each having a power amplifier, a variable phase shift circuit connected to an input portion of said power amplifier, a power detector connected to an output portion of said power amplifier, and a phase amount table which is constructed on the basis of the characteristics of said power amplifier;

a plurality of antennas which are respectively connected to said plurality of transmission signal amplifiers;

tilt angle control circuit having a plurality of control lines which are respectively connected to said plurality of transmission signal amplifiers; and

a comparison control circuit for comparing an output of said power detector with a control signal of said tilt angle control circuit to generate a phase shift amount control signal on the basis of the contents of said phase shift amount table to supply the phase shift amount control signal to said variable phase shift circuit, thereby controlling an input transmission signal phase shift amount.

27. A transmission system according to claim 26, wherein said power amplifier is either a feed forward power amplifier or a linear power amplifier.

28. A system for transmitting/receiving a signal having a carrier frequency band for a radio base station, said system comprising a plurality of transmission/reception signal amplifying devices which are individually connected to a plurality of antennas constituting an array antenna and a tilt angle control circuit having a plurality of control lines, each of said transmission/reception signal amplifying devices comprising:

a power amplifier;

a variable phase shift circuit connected to an input portion of said power amplifier;

a power detector connected to an output portion of said power amplifier; and

a phase shift amount control circuit for comparing an output of said power detector with a tilt angle control signal of said tilt angle control circuit to control the phase shift amount of said variable phase shift circuit on the basis of the comparison result and the contents of a phase shift amount table which is produced in relation to the characteristics of said power amplifier.

29. A system for transmitting/receiving a signal having a carrier frequency band for a radio base station, said system comprising a plurality of transmission/reception signal amplifying devices which are individually connected to a plurality of antennas constituting an array antenna and a plurality of tilt angle control circuits, each of said transmission/reception signal amplifying devices comprising:

a transmission power amplifier; and

a variable phase shift circuit connected to an input portion of said transmission power amplifier for phase-shifting an input transmission signal in correspondence to the characteristics of said transmission power amplifier,

wherein each of said transmission/reception signal amplifying devices is constructed in such a way as to take partial charge of the overall electric power which is to be radiated from said antennas into the air.

30. A system according to claim 29, wherein each of said transmission/reception signal amplifying devices comprises:

a power detector connected to an output portion of said transmission power amplifier; and

a phase shift amount control circuit for comparing an output of said power detector with a tilt angle control signal of said tilt angle control circuit to control the phase shift amount of said variable phase shift circuit on the basis of the comparison result and the contents of a phase shift amount table which is produced in relation to the characteristics of said power amplifier.