Load modulation amplifier with reconfigurable fallback interval

Abstract

The invention relates to a rollback interval reconfigurable load modulation amplifier, which comprises a reconfigurable power divider, a phase shifter, a carrier power amplifier and a balanced power amplifier, and is characterized in that the input end of the reconfigurable power divider is the input end of the load modulation amplifier and is used for accessing a radio frequency input signal; the first output end of the reconfigurable power divider is connected with the input end of the phase shifter, and the second output end of the reconfigurable power divider is connected with the first input end of the balanced power amplifier; the reconfigurable power divider comprises a microstrip line and a radio frequency switch, and the power dividing ratio of the first output end to the second output end of the reconfigurable power divider is controlled through on-off of the radio frequency switch. The output end of the phase shifter is connected with the input end of the carrier power amplifier; the output end of the carrier power amplifier is connected with the second input end of the balanced power amplifier, and the output end of the balanced power amplifier is the output end of the load modulation amplifier and used for being connected with a load. According to the invention, high efficiency can be realized in different fallback interval ranges, so that the fallback interval efficiency of the power amplifier is improved, and the requirement of the high-throughput satellite communication system for high fallback interval efficiency is met.

Description

Technical Field

[0001] The present invention relates to the technical field of radio frequency front-end circuits, and in particular to a load modulation amplifier with a reconfigurable back-off interval. Background Art

[0002] With the rapid development of satellite communications, users' demand for low latency and high transmission rates has increased explosively. On the one hand, in order to improve the efficiency of spectrum utilization and alleviate the current shortage of spectrum resources, high-order modulation schemes are widely used in satellite communication systems. However, these high-order modulation schemes will cause the peak-to-average ratio of the modulated signal to vary between 6dB and 10dB. Traditional power amplifiers are difficult to meet the needs of amplifying high peak-to-average ratio modulated signals. Therefore, it is urgent to propose a new architecture to expand the range of the power amplifier back-off interval. On the other hand, traditional power amplifiers are inefficient in the back-off interval, so it is necessary to improve the efficiency of the power amplifier in the back-off interval. In addition, the power amplifier also needs to be able to amplify modulated signals with different peak-to-average ratios, which requires the back-off efficiency of the power amplifier to be as high as possible, and it can also support the amplification of modulated signals with different peak-to-average ratios to reduce the construction cost of the entire satellite communication system.

[0003] Currently, reconfigurable load modulation amplifiers have attracted attention because they can easily achieve a large back-off range. However, this type of amplifier cannot improve the efficiency in different back-off ranges and can only achieve efficiency improvement within a fixed back-off range. Summary of the invention

[0004] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide a load modulation amplifier with a reconfigurable back-off interval, which has the characteristics of a large back-off interval and high efficiency in the back-off interval, and realizes three peak efficiency points in a high back-off interval, thereby achieving the purpose of high efficiency of the power amplifier within a large back-off interval.

[0005] To achieve the above-mentioned purpose, the present invention provides a load modulation amplifier with a reconfigurable back-off interval, comprising a reconfigurable power divider, a phase shifter, a carrier power amplifier and a balanced power amplifier.

[0006] The input end of the reconfigurable power divider is the input end of the load modulation amplifier, which is used to access the RF input signal; the first output end of the reconfigurable power divider is connected to the input end of the phase shifter, and the second output end is connected to the first input end of the balanced power amplifier; the reconfigurable power divider includes a microstrip line and a RF switch, and the power division ratio between the first output end and the second output end is controlled by turning the RF switch on and off;

[0007] The output end of the phase shifter is connected to the input end of the carrier power amplifier;

[0008] The output end of the carrier power amplifier is connected to the second input end of the balanced power amplifier, and the output end of the balanced power amplifier is the output end of the load modulation amplifier, which is used to be connected to a load.

[0009] According to a technical solution of the present invention, the carrier power amplifier includes a first power amplifier and a transmission line, and the input end of the first power amplifier is connected to the output end of the phase shifter.

[0010] According to a technical solution of the present invention, the reconfigurable power divider includes a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, a first radio frequency switch and a second radio frequency switch.

[0011] The first end and the second end of the first microstrip line are respectively connected to the input end and the first output end of the reconfigurable power divider;

[0012] The first end of the second microstrip line is connected to the first end of the first microstrip line, and the second end of the second microstrip line is connected to the first end of the third microstrip line through the first radio frequency switch;

[0013] The second end of the third microstrip line is connected to the first end of the fourth microstrip line, and the second end of the fourth microstrip line is connected to the second output end of the reconfigurable power divider;

[0014] The first end of the fifth microstrip line is connected to the second end of the first microstrip line, and the second end of the fifth microstrip line is connected to the first end of the sixth microstrip line through the second RF switch;

[0015] The second end of the sixth microstrip line is connected to the second end of the fourth microstrip line;

[0016] According to a technical solution of the present invention, during operation, the impedance of the first microstrip line is Its electrical length is θ; the impedance of the second microstrip line is Z0, and its electrical length is θ / 2; the impedance of the third microstrip line is Z0, and its electrical length is θ / 2; the impedance of the fourth microstrip line is Its electrical length is θ; the impedance of the fifth microstrip line is Z0, and its electrical length is θ / 2; the impedance of the sixth microstrip line is Z0, and its electrical length is θ / 2.

[0017] According to a technical solution of the present invention, the first RF switch and the second RF switch are PIN diodes, the third poles of the first RF switch and the second RF switch are grounded, the positive pole and the negative pole of the first RF switch are respectively connected to the second microstrip line and the third microstrip line, and the negative pole and the positive pole of the second RF switch are respectively connected to the fifth microstrip line and the sixth microstrip line.

[0018] According to a technical solution of the present invention, the first RF switch and the second RF switch are turned on, the output power division ratio between the first end and the second end of the reconfigurable power divider is 1:1, and the load modulation amplifier is in LMBA mode;

[0019] The first RF switch and the second RF switch are turned off, the output power division ratio between the first end and the second end of the reconfigurable power divider is 0:1, and the load modulation amplifier is in Doherty mode.

[0020] According to a technical solution of the present invention, the balanced power amplifier includes a second power amplifier and a third power amplifier, and further includes:

[0021] An input quadrature coupler, wherein the fourth port thereof is connected to the second port of the reconfigurable power amplifier; the third port thereof is connected to one end of an isolation resistor, the other end of the isolation resistor is grounded; the second port thereof is connected to the output end of the second power amplifier; and the first port thereof is connected to the input end of the third power amplifier;

[0022] An output orthogonal coupler, wherein a first port thereof is connected to the output end of the second power amplifier, a second port thereof is connected to the output end of the third power amplifier; a third port thereof is connected to the output end of the carrier power amplifier, and a fourth port thereof is connected to the total output end.

[0023] According to a technical solution of the present invention, the resistance of the isolation resistor is 50Ω.

[0024] According to a technical solution of the present invention, the phase shifter is a microstrip line phase shifter, the characteristic impedance of the phase shifter is 50 ohms, and the electrical length of the phase shifter is 90°.

[0025] According to a technical solution of the present invention, when the load modulation amplifier is in Doherty mode, the first power amplifier works in class AB state, and the second power amplifier works in class C state;

[0026] When the load modulation amplifier is in the LMBA mode, the first power amplifier and the second power amplifier operate in a class AB state, and the third power amplifier operates in a class C state.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention proposes a load modulation amplifier with a reconfigurable back-off interval. The first power amplifier PA1 in the carrier power amplifier, the second power amplifier PA2 in the balanced power amplifier, and the third power amplifier PA3 form a third-order load modulation mechanism, which realizes three peak efficiency points in a high back-off interval, thereby achieving the purpose of high efficiency of the power amplifier in a large back-off interval. The present invention, by introducing a power divider with a reconfigurable power division ratio, realizes the working modes of Doherty and LMBA. The power amplifier can not only realize the reconstruction of the back-off interval range, but also significantly improve the efficiency of the back-off interval, solving the problem that the traditional load modulation balanced amplifier is fixed in the back-off interval. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 A circuit structure diagram of a load modulation amplifier with a reconfigurable back-off interval provided in accordance with an embodiment of the present invention is schematically shown;

[0031] Figure 2 A schematic diagram showing a circuit structure of a reconfigurable power divider provided according to an embodiment of the present invention;

[0032] Figure 3 The figure schematically shows a simulation result according to an embodiment of the present invention.

[0033] The corresponding relationship between the reference numerals and component names is as follows:

[0034] 1. Reconfigurable power divider; 2. Phase shifter; 3. Carrier power amplifier; 4. Balanced power amplifier;

[0035] 11. a first microstrip line; 12. a second microstrip line; 13. a third microstrip line; 14. a fourth microstrip line; 15. a fifth microstrip line; 16. a sixth microstrip line; 17. a first radio frequency switch; 18. a second radio frequency switch;

[0036] PA1, the first power amplifier; PA2, the second power amplifier; PA3, the third power amplifier. DETAILED DESCRIPTION

[0037] The description of the embodiments of this specification should be combined with the corresponding drawings, which should be considered as part of the complete specification. In the drawings, the shape or thickness of the embodiments may be enlarged and indicated for simplification or convenience. Furthermore, the parts of each structure in the drawings will be described separately. It is worth noting that the elements not shown in the drawings or not described in words are in a form known to ordinary technicians in the relevant technical field.

[0038] The description of the embodiments herein and any reference to directions and orientations are only for the convenience of description and are not to be construed as any limitation on the scope of protection of the present invention. The following description of the preferred embodiments may involve combinations of features, which may exist independently or in combination, and the present invention is not particularly limited to the preferred embodiments. The scope of the present invention is defined by the claims.

[0039] like Figure 1 As shown, a load modulation amplifier with a reconfigurable back-off interval of the present invention comprises a reconfigurable power divider 1, a phase shifter 2, a carrier power amplifier 3 and a balanced power amplifier 4.

[0040] The input end of the reconfigurable power divider 1 is the input end of the load modulation amplifier, which is used to access the RF input signal; the first output end of the reconfigurable power divider 1 is connected to the input end of the phase shifter 2, and its second output end is connected to the first input end of the balanced power amplifier 4; the reconfigurable power divider 1 includes a microstrip line and a RF switch, and the power division ratio of its first output end and the second output end is controlled by turning the RF switch on and off; the output end of the phase shifter 2 is connected to the input end of the carrier power amplifier 3; the output end of the carrier power amplifier 3 is connected to the second input end of the balanced power amplifier 4, and the output end of the balanced power amplifier 4 is the output end of the load modulation amplifier, which is used to be connected to the load.

[0041] The carrier power amplifier 3 includes a first power amplifier PA1 and a transmission line, and an input end of the first power amplifier PA1 is connected to an output end of the phase shifter 2 .

[0042] The reconfigurable power divider 1 includes a first microstrip line 11, a second microstrip line 12, a third microstrip line 13, a fourth microstrip line 14, a fifth microstrip line 15, a sixth microstrip line 16, a first radio frequency switch 17 and a second radio frequency switch 18. The first end and the second end of the first microstrip line 11 are respectively connected to the input end and the first output end of the reconfigurable power divider 1; the first end of the second microstrip line 12 is connected to the first end of the first microstrip line 11, and the second end thereof is connected to the first end of the third microstrip line 13 through the first radio frequency switch 17; the second end of the third microstrip line 13 is connected to the first end of the fourth microstrip line 14, and the second end of the fourth microstrip line 14 is connected to the second output end of the reconfigurable power divider 1; the first end of the fifth microstrip line 15 is connected to the second end of the first microstrip line 11, and the second end of the fifth microstrip line 15 is connected to the first end of the sixth microstrip line 16 through the second radio frequency switch 18; the second end of the sixth microstrip line 16 is connected to the second end of the fourth microstrip line 14.

[0043] During operation, the impedance of the first microstrip line 11 is Its electrical length is θ; the impedance of the second microstrip line 12 is Z0, and its electrical length is θ / 2; the impedance of the third microstrip line 13 is Z0, and its electrical length is θ / 2; the impedance of the fourth microstrip line 14 is Its electrical length is θ; the impedance of the fifth microstrip line 15 is Z0, and its electrical length is θ / 2; the impedance of the sixth microstrip line 16 is Z0, and its electrical length is θ / 2.

[0044] The first RF switch 17 and the second RF switch 18 are PIN diodes, and the third poles of the first RF switch 17 and the second RF switch 18 are grounded. The positive pole and the negative pole of the first RF switch 17 are connected to the second microstrip line 12 and the third microstrip line 13 respectively, and the negative pole and the positive pole of the second RF switch 18 are connected to the fifth microstrip line 15 and the sixth microstrip line 16 respectively.

[0045] The balanced power amplifier 4 includes a second power amplifier PA2 and a third power amplifier PA3, and further includes:

[0046] An input quadrature coupler, wherein the fourth port thereof is connected to the second port of the reconfigurable power amplifier; the third port thereof is connected to one end of an isolation resistor, and the other end of the isolation resistor is grounded; the second port thereof is connected to the output end of the second power amplifier PA2; and the first port thereof is connected to the input end of the third power amplifier PA3;

[0047] The output orthogonal coupler has a first port connected to the output end of the second power amplifier PA2, a second port connected to the output end of the third power amplifier PA3; a third port connected to the output end of the carrier power amplifier 3, and a fourth port connected to the total output end.

[0048] The resistance value of the isolation resistor is 50Ω. The phase shifter 2 is a microstrip line phase shifter, the characteristic impedance of the phase shifter 2 is 50 ohms, and the electrical length of the phase shifter 2 is 90°.

[0049] The first RF switch 17 and the second RF switch 18 are turned on, the output power division ratio between the first end and the second end of the reconfigurable power divider 1 is 1:1, and the load modulation amplifier is in the LMBA mode;

[0050] The first RF switch 17 and the second RF switch 18 are turned off, the output power division ratio between the first end and the second end of the reconfigurable power divider 1 is 0:1, and the load modulation amplifier is in Doherty mode.

[0051] According to a technical solution of the present invention, when the load modulation amplifier is in Doherty mode, the first power amplifier PA1 works in the class AB state, the second power amplifier PA2 works in the class C state, and the back-off interval is 6dB;

[0052] When the load modulation amplifier is in the LMBA mode, the first power amplifier PA1 and the second power amplifier PA2 work in the class AB state, the third power amplifier PA3 works in the class C state, and the back-off interval of the entire load modulation amplifier is 10dB.

[0053] Figure 3 The simulation results of the load modulation amplifier example with reconfigurable back-off interval are shown. Figure 3 It can be seen that when the load modulation amplifier works in LMBA mode, its back-off point is 34dBm and the back-off range is 10dB. When the load modulation amplifier works in Doherty mode by adjusting the RF switch, its back-off point is 38dBm and the back-off range is 6dB. These two different working modes reconstruct the back-off range of the load modulation amplifier to 6dB and 10dB respectively.

[0054] [It can be seen from the above embodiment that by adjusting the power division ratio of the reconfigurable power divider, the reconstruction of the 10dB and 6dB back-off ranges is achieved, and finally the Doherty-like and LMBA working modes are realized. The load modulation amplifier architecture with reconfigurable back-off interval proposed by the present invention has the ability to reconfigure the back-off interval range and effectively improve the efficiency within different back-off intervals.

[0055] It should be noted that the above is a preferred embodiment of the present invention. It should be pointed out that although the preferred embodiment of the present invention has been described, once the basic creative concept of the present invention is known, a number of improvements and modifications can be made by a person skilled in the art without departing from the principles of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention. Therefore, the attached claims are intended to be interpreted as including the preferred embodiment and all changes and modifications that fall within the scope of the embodiments of the present invention.

Claims

1. A load modulation amplifier with reconfigurable back-off interval, characterized in that: It includes a reconfigurable power divider (1), a phase shifter (2), a carrier power amplifier (3) and a balanced power amplifier (4), The input end of the reconfigurable power divider (1) is the input end of the load modulation amplifier, and is used to receive the radio frequency input signal; the first output end of the reconfigurable power divider (1) is connected to the input end of the phase shifter (2), and the second output end is connected to the first input end of the balanced power amplifier (4); the reconfigurable power divider (1) comprises a microstrip line and a radio frequency switch, and the power division ratio between the first output end and the second output end is controlled by turning the radio frequency switch on and off; The output end of the phase shifter (2) is connected to the input end of the carrier power amplifier (3); The output end of the carrier power amplifier (3) is connected to the second input end of the balanced power amplifier (4); the output end of the balanced power amplifier (4) is the output end of the load modulation amplifier and is used to be connected to a load.

2. The load modulation amplifier with reconfigurable back-off interval according to claim 1, characterized in that: The carrier power amplifier (3) comprises a first power amplifier (PA1) and a transmission line, and the input end of the first power amplifier (PA1) is connected to the output end of the phase shifter (2).

3. The load modulation amplifier with reconfigurable back-off interval according to claim 2, characterized in that: The reconfigurable power divider (1) comprises a first microstrip line (11), a second microstrip line (12), a third microstrip line (13), a fourth microstrip line (14), a fifth microstrip line (15), a sixth microstrip line (16), a first radio frequency switch (17) and a second radio frequency switch (18), The first end and the second end of the first microstrip line (11) are respectively connected to the input end and the first output end of the reconfigurable power divider (1); The first end of the second microstrip line (12) is connected to the first end of the first microstrip line (11), and the second end thereof is connected to the first end of the third microstrip line (13) via the first radio frequency switch (17); The second end of the third microstrip line (13) is connected to the first end of the fourth microstrip line (14), and the second end of the fourth microstrip line (14) is connected to the second output end of the reconfigurable power divider (1); The first end of the fifth microstrip line (15) is connected to the second end of the first microstrip line (11), and the second end of the fifth microstrip line (15) is connected to the first end of the sixth microstrip line (16) via the second radio frequency switch (18); The second end of the sixth microstrip line (16) is connected to the second end of the fourth microstrip line (14).

4. The load modulation amplifier with reconfigurable back-off interval according to claim 3, characterized in that: During operation, the impedance of the first microstrip line (11) is Its electrical length is θ; the impedance of the second microstrip line (12) is Z0, and its electrical length is θ / 2; the impedance of the third microstrip line (13) is Z0, and its electrical length is θ / 2; the impedance of the fourth microstrip line (14) is Its electrical length is θ; the impedance of the fifth microstrip line (15) is Z0, and its electrical length is θ / 2; the impedance of the sixth microstrip line (16) is Z0, and its electrical length is θ / 2.

5. The load modulation amplifier with reconfigurable back-off interval according to claim 3, characterized in that: The first radio frequency switch (17) and the second radio frequency switch (18) are PIN diodes, the third electrodes of the first radio frequency switch (17) and the second radio frequency switch (18) are grounded, the positive electrode and the negative electrode of the first radio frequency switch (17) are respectively connected to the second microstrip line (12) and the third microstrip line (13), and the negative electrode and the positive electrode of the second radio frequency switch (18) are respectively connected to the fifth microstrip line (15) and the sixth microstrip line (16).

6. The load modulation amplifier with reconfigurable back-off interval according to claim 4, characterized in that: The first radio frequency switch (17) and the second radio frequency switch (18) are turned on, the output power division ratio between the first end and the second end of the reconfigurable power divider (1) is 1:1, and the load modulation amplifier is in LMBA mode; The first radio frequency switch (17) and the second radio frequency switch (18) are turned off, the output power division ratio between the first end and the second end of the reconfigurable power divider (1) is 0:1, and the load modulation amplifier is in Doherty mode.

7. The load modulation amplifier with reconfigurable back-off interval according to claim 6, characterized in that: The balanced power amplifier (4) comprises a second power amplifier (PA2) and a third power amplifier (PA3), and further comprises: an input quadrature coupler, wherein the fourth port thereof is connected to the second port of the reconfigurable power amplifier; the third port thereof is connected to one end of an isolation resistor, the other end of the isolation resistor being grounded; the second port thereof is connected to the output end of the second power amplifier (PA2); and the first port thereof is connected to the input end of the third power amplifier (PA3); An output quadrature coupler, wherein a first port of the output coupler is connected to the output end of the second power amplifier (PA2), a second port of the output coupler is connected to the output end of the third power amplifier (PA3); a third port of the output coupler is connected to the output end of the carrier power amplifier (3), and a fourth port of the output coupler is connected to the total output end.

8. The load modulation amplifier with reconfigurable back-off interval according to claim 7, characterized in that: The resistance of the isolation resistor is 50Ω.

9. The load modulation amplifier with reconfigurable back-off interval according to claim 7, characterized in that: The phase shifter (2) is a microstrip line phase shifter, the characteristic impedance of the phase shifter (2) is 50 ohms, and the electrical length of the phase shifter (2) is 90°.

10. The load modulation amplifier with reconfigurable back-off interval according to claim 8, characterized in that: When the load modulation amplifier is in Doherty mode, the first power amplifier (PA1) operates in a class AB state, and the second power amplifier (PA2) operates in a class C state; When the load modulation amplifier is in the LMBA mode, the first power amplifier (PA1) and the second power amplifier (PA2) operate in a class AB state, and the third power amplifier (PA3) operates in a class C state.

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