A high-efficiency broadband power amplifier and a radio frequency transceiver

Abstract

The present invention discloses a high-efficiency broadband power amplifier and a radio frequency transceiver, which include an input port, a broadband input matching circuit, an input broadband DC bias circuit, a power amplification transistor, an output broadband DC bias circuit, a low-pass filter network, an auxiliary matching transmission line and an output load; one end of the input port is connected to one end of the broadband input matching circuit, and the other end thereof is connected to the gate of the power amplification transistor. The drain of the power amplification transistor is respectively connected to one end of the output broadband DC bias circuit and the low-pass filter network. The other end of the low-pass filter network, the auxiliary matching transmission line and the output load are connected in sequence. The input broadband DC bias circuit is connected to the broadband input matching circuit, and the source of the power amplification transistor is grounded. The present invention can operate within a very wide frequency band range, adapt to various communication frequency bands, and has various performances such as small size and high efficiency, and is applicable to many radio frequency systems.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication, and particularly to a high-efficiency broadband power amplifier and a radio frequency transceiver. Background Art

[0002] With the deployment of the current 4G-LTE system and the promotion of the future 5G system, the next-generation wireless communication system needs to operate in multiple communication standards and frequency bands to cope with different application scenarios. A communication system that supports multi-mode and multi-frequency operation can also greatly save the costs of enterprises in R & D, replacement, and maintenance of a large number of devices. The power amplifier is a key component in the radio frequency transceiver. High efficiency is an important indicator of the power amplifier because it accounts for 40%-60% of the energy consumption of the base station. The improvement of its efficiency will greatly extend the service life of the device battery. On the other hand, the reduction of power consumption in the base station equipment will reduce resource consumption and carbon dioxide emissions. The high-efficiency broadband power amplifier has good scalability in terms of potential compatibility with future wireless communication standards. Therefore, the high-efficiency broadband power amplifier has very important research value.

[0003] In recent years, regarding how to design a broadband power amplifier, the academic community has proposed some solutions. For example, the real-frequency technique is used to implement a broadband matching network. However, it is difficult to implement the real-frequency technique when the bandwidth exceeds one octave. Moreover, the generated network may not meet the actual processing requirements. In addition, some scholars have proposed using a Chebyshev low-pass filter network as the input and output matching network of the broadband power amplifier. However, the roll-off generated by this method is too gentle, which is not conducive to suppressing harmonics. To solve the above problems, some scholars have improved the Chebyshev low-pass filter network to form an elliptical filter response, thus improving the harmonic suppression effect. However, the impedance matching of the entire working frequency band is only based on the impedance at one frequency point. Therefore, the bandwidth can only be limited within one octave. Summary of the Invention

[0004] In order to overcome the defects and deficiencies existing in the prior art, the present invention provides a high-efficiency broadband power amplifier. The present invention is based on a low-pass filter matching network. By using quarter-wavelength and half-wavelength open stubs, an elliptical filter response can be generated, and a working bandwidth exceeding 2 octaves and a broadband harmonic suppression effect exceeding the third harmonic can be achieved.

[0005] Another object of the present invention is to provide a radio frequency transceiver.

[0006] The present invention adopts the following technical solutions:

[0007] A high-efficiency broadband power amplifier includes an input port, a broadband input matching circuit, an input broadband DC bias circuit, a power amplification transistor, an output broadband DC bias circuit, a low-pass filter network, an auxiliary matching transmission line, and an output load;

[0008] The input port is connected to one end of the broadband input matching circuit, and the other end is connected to the gate of the power amplification transistor. The drain of the power amplification transistor is respectively connected to one end of the output broadband DC bias circuit and the low-pass filter network. The other end of the low-pass filter network, the auxiliary matching transmission line, and the output load are connected in sequence. The input broadband DC bias circuit is connected to the broadband input matching circuit, and the source of the power amplification transistor is grounded.

[0009] The broadband input matching network includes a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, and a seventh microstrip line connected in sequence.

[0010] The low-pass filter network has an elliptical filter response and includes two quarter-wavelength open stubs, a section of microstrip line, and a half-wavelength open stub. The two quarter-wavelength open stubs are in parallel, and after being connected in series with a section of microstrip line, they are in parallel with the half-wavelength open stub.

[0011] The half-wavelength open stub is realized by a stepped impedance.

[0012] The input broadband DC bias circuit and the output broadband DC bias circuit have the same structure and size.

[0013] The input broadband DC bias circuit and the output broadband DC bias circuit both include a section of microstrip line equivalent to a quarter wavelength, two bypass capacitors, and two fan-shaped stubs. The two bypass capacitors and the two fan-shaped stubs are connected in parallel and then connected in series with a quarter-wavelength microstrip line.

[0014] The length and width of the auxiliary matching transmission line are determined by the optimal impedance matching point of the power amplifier.

[0015] The microstrip line equivalent to a quarter wavelength is realized by a stepped impedance.

[0016] The width of a section of series microstrip line and the quarter-wavelength open stub in the low-pass filter network are determined by the out-of-band rejection of the broadband power amplifier.

[0017] A radio frequency transceiver includes the high-efficiency broadband power amplifier according to any one of claims 1-9.

[0018] Advantages of the present invention:

[0019] (1) The present invention has a wide impedance matching bandwidth. Compared with the traditional broadband matching scheme, the present invention can achieve a bandwidth of more than 2 octaves through a simpler structure.

[0020] (2) The harmonic suppression effect of the present invention is good. Compared with the gentle roll-off of the traditional Chebyshev low-pass matching network, the present invention realizes a steeper roll-off through a broadband bias circuit, thereby achieving better harmonic suppression and harmonic suppression effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 FIG. is a schematic structural diagram of a high-efficiency broadband power amplifier based on a low-pass filter matching network according to the present invention;

[0022] Figure 2 FIG. is a graph showing the results of the drain efficiency and gain of the present invention varying with the output power at 0.8, 1.3, 1.8, 2.3, and 2.8 GHz;

[0023] Figure 3 FIG. is a graph showing the test results of the output power, gain, and drain efficiency of the present invention over the entire frequency band.

[0024] Figure 4 FIG. is the result of the output power of the present invention varying with frequency in the test and simulation. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0026] Embodiment

[0027] As Figure 1 and Figure 2 shown, a high-efficiency broadband power amplifier includes an input port, a broadband input matching circuit, a broadband DC bias circuit, a power amplification transistor, a low-pass filter network, and an auxiliary matching transmission line. The broadband DC bias circuit includes an input broadband DC bias circuit and an output broadband DC bias circuit.

[0028] The input port is connected to one end of the broadband input matching circuit, and the other end thereof is connected to the gate of the power amplification transistor. The drain of the power amplification transistor is respectively connected to one end of the output broadband DC bias circuit and the low-pass filter network. The other end of the low-pass filter network, the auxiliary matching transmission line, and the output load are connected in sequence. The input broadband DC bias circuit is connected to the broadband input matching circuit, and the source of the power amplification transistor is grounded.

[0029] In this embodiment, the wavelength refers to the wavelength of the center frequency of the operating frequency band.

[0030] The broadband input matching circuit is composed of a third microstrip line 3, a fourth microstrip line 4, a fifth microstrip line 5, a sixth microstrip line 6, and a seventh microstrip line 7 connected in sequence. The third microstrip line is connected to the input port 1 through a first capacitor C1 and a second microstrip line 2. The width and length of the microstrip lines in the broadband input matching circuit are obtained from the optimal source impedance obtained through actual traction. The other end of the seventh microstrip line is connected to the gate of the power amplification transistor T.

[0031] The structural dimensions of the input broadband DC bias circuit and the output broadband DC bias circuit are the same.

[0032] The input broadband DC bias circuit is connected between the sixth microstrip line and the seventh microstrip line, and includes a microstrip line equivalent to a quarter wavelength, two bypass circuits, and two fan-shaped stubs. The two bypass capacitors and the two fan-shaped stubs are connected in parallel and then connected in series with a microstrip line equivalent to a quarter wavelength. The implementation method of this embodiment includes a ninth microstrip line 9, a tenth microstrip line 10, a second bypass capacitor C2, a third bypass capacitor C3, a first fan-shaped stub 11, a second fan-shaped stub 12, and a thirteenth microstrip line 13. The ninth microstrip line and the tenth microstrip line form an equivalent quarter-wavelength line, which is realized through stepped impedance. The specific connection method is as follows: one end of the ninth microstrip line is connected between the sixth and seventh microstrip lines, and the other end is connected in series with one end of the tenth microstrip line. The other end of the tenth microstrip line is respectively connected to the first bypass capacitor C2, the first fan-shaped stub 11, and the second fan-shaped stub 12. The other end of the first bypass capacitor C2 is grounded. The other end of the thirteenth microstrip line is respectively connected to the first bypass capacitor C2, the first fan-shaped stub 11, and the second fan-shaped stub 12, and the other end is respectively connected to the second bypass capacitor C3 and the voltage V G connected, where V G is -3.1V.

[0033] The output broadband DC bias circuit is respectively connected to one end of a fourteenth microstrip line 14 and one end of a twentieth microstrip line 20. The other end of the fourteenth microstrip line is connected to the drain of the power amplification transistor, and the source of the power amplification transistor is grounded. The fourteenth microstrip line and the twentieth microstrip line play a role in adjusting the harmonic impedance, and their length and width are determined by the optimal second harmonic impedance matching point of the power amplification transistor.

[0034] The output broadband DC bias circuit includes a microstrip line equivalent to a quarter wavelength, two bypass circuits, and two fan-shaped stubs. The two bypass capacitors and the two fan-shaped stubs are connected in parallel and then connected in series with a quarter-wavelength microstrip line. The equivalent quarter-wavelength line is realized through stepped impedance (the fifteenth microstrip line and the sixteenth microstrip line), and a zero point is introduced on the right side of the passband to achieve a steeper roll-off, so as to achieve better harmonic suppression.

[0035] In this embodiment, the output broadband DC bias circuit specifically includes a fifteenth microstrip line 15, a sixteenth microstrip line 16, a third bypass capacitor C4, a fourth bypass capacitor C5, a third sector branch 17, a fourth sector branch 18, and a nineteenth microstrip line 19. One end of the fifteenth microstrip line is connected between the fourteenth microstrip line and the twentieth microstrip line, and the other end is connected to one end of the sixteenth microstrip line. The other end of the sixteenth microstrip line is respectively connected to the fourth bypass capacitor and two sector branches. That is to say, the bypass capacitor and the two sector branches are in a parallel relationship. One end of the nineteenth capacitor is respectively connected to the two sector branches, and the other end is respectively connected to the third bypass capacitor and voltage V D connected, where V D is 28V.

[0036] The low-pass filter network includes two parallel quarter-wavelength open-circuit stubs (the twenty-first and twenty-second microstrip lines), a section of series microstrip line (the twenty-third microstrip line), and a parallel half-wavelength open-circuit stub (the twenty-fourth microstrip line). The half-wavelength open-circuit stub is realized by a stepped impedance.

[0037] The width of the section of series microstrip line (the twenty-third microstrip line) and the parallel quarter-wavelength open-circuit stubs is determined by the out-of-band rejection of the broadband power amplifier.

[0038] By using quarter-wavelength and half-wavelength open-circuit stubs, the present invention can also generate an elliptical filter response, and can achieve a working bandwidth of more than 2 times the frequency and a broadband harmonic suppression effect of more than 3 times the harmonic.

[0039] In this embodiment, the low-pass filter network with an elliptical filter response is used as the broadband output matching network of the power amplifier, and a section of auxiliary matching transmission line is used to assist the low-pass filter network to achieve broadband impedance matching. At the same time, the broadband DC bias circuit in the output part can generate a zero point at a very close distance to the right of the passband, thereby generating a very steep roll-off and providing a harmonic suppression effect.

[0040] In this embodiment, the low-pass filter network includes a twenty-first microstrip line 21, a twenty-second microstrip line 22, a twenty-third microstrip line 23, and a twenty-fourth microstrip line 24. The twenty-third microstrip line is respectively connected to the twenty-first microstrip line, the twenty-second microstrip line, and the twentieth microstrip line. The other end of the twenty-third microstrip line is respectively connected to the twenty-fourth microstrip line 24 and the auxiliary matching transmission line.

[0041] The auxiliary matching connection line is composed of a twenty-fifth microstrip line 25. The length and width are determined by the optimal impedance matching point of the power amplifier transistor. The twenty-fifth microstrip line is connected to the load through a second capacitor C6 and a twenty-sixth microstrip line 26.

[0042] In the present invention, a broadband filter matching network and a broadband DC bias circuit are used in combination with an auxiliary transmission line to achieve impedance matching within a broadband range, and at the same time, harmonic suppression in the high-frequency part can also be achieved.

[0043] Figure 1 Show a block diagram of an embodiment of a high-efficiency broadband power amplifier based on a low-pass filter matching network. In the embodiment, the power amplification transistor T selected is the GaN HEMT CGH40010F of Cree Company. The power amplification transistor includes a gate G, a drain D, and a source S. The input terminal, output terminal, gate G DC bias voltage V G and drain D DC bias voltage V D As Figure 1 marked, the specific parameters are: V G =-3.1V, V D =28V.

[0044] For a high-efficiency broadband power amplifier based on a low-pass filter matching network in this example, the parameters of the PCB circuit board dielectric material selected for processing are as follows: ε r =2.2, h = 0.813, tanδ = 0.0027.

[0045] It can be seen from Figure 2 that when the power amplifier reaches saturation output at the measured frequency points, the efficiency is greater than 60%, and the gain is greater than 10 dB.

[0046] Figure 3 Show the test results of the output power, gain, and drain efficiency of the described high-efficiency broadband power amplifier based on a low-pass filter matching network in the entire frequency band. In the frequency band range of 0.5 GHz - 3.2 GHz, the drain efficiency is 56.7% - 74.9%, the output power is 38.6 dBm - 42.87 dBm, and the gain is 8 dB - 15.67 dB.

[0047] Figure 4 Show the results of the output power varying with frequency in the test and simulation. Among them, the output power in the test and simulation fits well before 4.2 GHz, and there is obvious harmonic suppression starting from 3.4 GHz. From the simulation results, the harmonic suppression can reach 10 GHz.

[0048] The broadband DC bias circuit does not affect the RF signal path. The low-pass filter matching network is used to achieve broadband impedance transformation and harmonic suppression in the high-frequency part. It has an elliptical filter response. The auxiliary matching transmission line is used to assist the low-pass filter matching network to achieve broadband impedance matching. Compared with the traditional low-pass filter network, the low-pass filter matching network used in the present invention, in cooperation with the bias circuit, can achieve a steeper roll-off and better harmonic suppression while realizing the function of broadband impedance matching.

[0049] In summary, the high-efficiency broadband power amplifier based on a low-pass filter matching network proposed by the present invention can operate in a very wide frequency band range, adapt to multiple communication frequency bands, and has various performances such as small size and high efficiency, and is applicable to many RF systems.

[0050] Any of the above high-efficiency broadband power amplifiers can be applied to RF transceivers and integrated circuits.

[0051] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A high-efficiency broadband power amplifier, characterized in that, it includes an input port, a broadband input matching circuit, an input broadband DC bias circuit, a power amplification transistor, an output broadband DC bias circuit, a low-pass filter network, an auxiliary matching transmission line, and an output load; the input port is connected to one end of the broadband input matching circuit, the other end of the broadband input matching circuit is connected to the gate of the power amplification transistor, the drain of the power amplification transistor is respectively connected to one end of the output broadband DC bias circuit and the low-pass filter network, the other end of the low-pass filter network, the auxiliary matching transmission line, and the output load are connected in sequence, the input broadband DC bias circuit is connected to the broadband input matching circuit, and the source of the power amplification transistor is grounded; the low-pass filter network has an elliptical filter response and includes two quarter-wavelength open stubs, a section of microstrip line, and a half-wavelength open stub, the two quarter-wavelength open stubs are in parallel, and after being connected in series with a section of microstrip line, they are in parallel with the half-wavelength open stub; the half-wavelength open stub is realized by a stepped impedance; both the input broadband DC bias circuit and the output broadband DC bias circuit include a section of equivalent quarter-wavelength microstrip line, two bypass capacitors, and two fan-shaped stubs, and after the two bypass capacitors and the two fan-shaped stubs are connected in parallel, they are connected in series with a section of quarter-wavelength microstrip line.

2. The high-efficiency broadband power amplifier according to claim 1, characterized in that, the broadband input matching network includes a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line, and a seventh microstrip line connected in sequence.

3. The high-efficiency broadband power amplifier according to claim 1, characterized in that, the input broadband DC bias circuit and the output broadband DC bias circuit have the same structure and size.

4. The high-efficiency broadband power amplifier according to claim 1, characterized in that, the length and width of the auxiliary matching transmission line are determined by the optimal impedance matching point of the power amplifier.

5. The high-efficiency broadband power amplifier according to claim 4, characterized in that, the equivalent quarter-wavelength microstrip line is realized by a stepped impedance.

6. The high-efficiency broadband power amplifier according to claim 1, characterized in that, the width of a section of series microstrip line and the quarter-wavelength open stub in the low-pass filter network are determined by the out-of-band rejection of the broadband power amplifier.

7. A radio frequency transceiver, characterized in that, it includes the high-efficiency broadband power amplifier according to any one of claims 1-6.

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