A Tuned Dual-Band Matching Power Amplifier

Abstract

The invention discloses a tuned dual-frequency matching power amplifier, comprising a dielectric plate, on which an input port, an input matching circuit, a stabilizing circuit, a transistor, a tuning circuit, a DC bias circuit, an output matching circuit and an output port are respectively arranged; the input port is connected to the input matching circuit, the input matching circuit is connected to the stabilizing circuit, the stabilizing circuit is connected to the gate of the transistor, the source of the transistor is grounded, its drain is connected to the tuning circuit, the tuning circuit is connected to the output matching circuit, and the output matching circuit is connected to the output port; the DC bias circuit is respectively connected to the gate and drain of the transistor to provide a gate bias voltage and a drain bias voltage. The whole power amplifier structure of the invention is simple and reliable, and is easy to process, with low cost and high power added efficiency. No power amplification is performed outside the working frequency band, and spectrum resources are better utilized.

Description

Technical Field

[0001] The invention relates to the technical field of wireless communications, and in particular to a tuned dual-frequency matching power amplifier. Background Art

[0002] In recent years, with the rapid development of wireless communication and the advent of the fifth-generation communication system, the coexistence of more and more networks has put forward higher and higher requirements for communication systems that can support multiple frequency bands. Microstrip design amplifiers are widely used in power amplifier design due to their advantages such as light weight, small size, easy processing and low cost. As spectrum resources become increasingly scarce, there is an urgent need to fully improve spectrum utilization within very limited spectrum resources. Dual-frequency or multi-frequency power amplifiers are an effective solution to this demand and are increasingly used in communication transceiver systems. Using microstrip to design dual-frequency power amplifiers has great research significance.

[0003] The existing technologies are investigated and understood as follows:

[0004] In 2018, Professor Liu Yuanan and his graduate students proposed the rotation compensation of the impedance trajectory circle as a matching circuit for the power amplifier. Loading open-circuit branches forms a circular trajectory of impedance on the Smith chart, thereby achieving impedance matching at the corresponding frequency. The subsequent input and output impedance matching is also based on this principle.

[0005] In 2012, Kenle Chen et al. used a microstrip line structure to realize a tuning network for a power amplifier, and thereby realized a dual-band high-efficiency power amplifier combining class F and inverse class F.

[0006] In general, there are many studies on dual-band power amplifiers in existing work, but many design methods use simple dual-band impedance matching, which easily leads to a decrease in efficiency. Therefore, it is of great significance to design a simple tuned dual-band power amplifier. Summary of the invention

[0007] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and propose a tuned dual-band matching power amplifier. The entire power amplifier structure is simple and reliable, easy to process, low cost, high power added efficiency, no power amplification outside the working frequency band, and better utilization of spectrum resources.

[0008] To achieve the above-mentioned purpose, the technical solution provided by the present invention is: a tuned dual-frequency matching power amplifier, the power amplifier includes a dielectric plate with a copper layer on the upper surface and a ground layer on the lower surface, and the dielectric plate is respectively provided with an input port, an input matching circuit, a stabilization circuit, a transistor, a tuning circuit, a DC bias circuit, an output matching circuit and an output port; the input port is connected to the input matching circuit, and the input matching circuit is used to match the optimal gain input impedance of the power amplifier; the input matching circuit is connected to the stabilization circuit, and the stabilization circuit is used to prevent the generation of self-excitation to increase the in-band stability of the power amplifier; the stabilization circuit is connected to the gate of the transistor, the source of the transistor is grounded, and the drain is connected to the tuning circuit, and the harmonic impedance is adjusted to a high reflection state through the tuning circuit; the tuning circuit is connected to the output matching circuit, and the output impedance of the power amplifier with the optimal efficiency and output power is matched through the output matching circuit; the output matching circuit is connected to the output port; the DC bias circuit is respectively connected to the gate and drain of the transistor to provide a gate bias voltage and a drain bias voltage.

[0009] Furthermore, the operating frequency of the power amplifier is 1.4GHz and 2.0GHz. Through dual-frequency impedance matching and adjustment of harmonic impedance, it can achieve a bandwidth of more than 120MHz in each dual-band, and a power output of more than 39dBm in both dual-bands, and a power added efficiency of more than 59%.

[0010] Further, the input matching circuit includes a first transmission line, a second transmission line, a third transmission line and five open branches, one end of the first transmission line is respectively connected to the input port and an open branch, the other end of the first transmission line is connected to one end of the second transmission line, the other end of the second transmission line is connected to one end of the third transmission line, the other end of the third transmission line is connected to an open branch, and two symmetrically distributed open branches are connected between each two adjacent transmission lines, and the two open branches are located on both sides of the transmission line; wherein the five open branches generate two small circles symmetrical about the real axis as matching points on the Smith chart for the impedance trajectory of the input matching circuit, the admittance of the first transmission line and the second transmission line determines the size of the real part and the imaginary part of the matching point, and the function of the third transmission line is to rotate the matching impedance trajectory as a whole on the Smith chart to the desired matching state.

[0011] Further, the output matching circuit includes a fourth transmission line, a fifth transmission line, a sixth transmission line and three open branches, one end of the fourth transmission line is connected to the tuning circuit, and the other end thereof is connected to one end of the fifth transmission line, the other end of the fifth transmission line is connected to one end of the sixth transmission line, the other end of the sixth transmission line is connected to an open branch, and an open branch is connected between every two adjacent transmission lines, and all the open branches are located on the same side of the transmission line; wherein the three open branches generate two small circles symmetrical about the real axis as matching points on the Smith chart for the impedance trajectory of the output matching circuit, the admittance of the fifth transmission line and the sixth transmission line determines the size of the real part and the imaginary part of the matching point, and the function of the fourth transmission line is to rotate the matching impedance trajectory as a whole on the Smith chart to the desired matching state.

[0012] Further, the tuning circuit includes a seventh transmission line and four open branches, one end of the seventh transmission line is respectively connected to the drain of the transistor and two symmetrically distributed open branches, the two open branches are respectively a first open branch and a second open branch, and are located on both sides of the seventh transmission line, the other end of the seventh transmission line is respectively connected to the output matching circuit and two other symmetrically distributed open branches, the two open branches are respectively a third open branch and a fourth open branch, and are located on both sides of the seventh transmission line; wherein the first open branch and the second open branch are used to respectively adjust the second harmonic impedance of the two operating frequency points, so that the impedance is adjusted to 0, and the second harmonic impedance is in a short-circuit state; the function of the third open branch, the fourth open branch and the seventh transmission line is to adjust the third harmonic impedance of the two operating frequency points, so that the impedance is adjusted to infinity, and the third harmonic impedance is in a short-circuit state.

[0013] Further, the DC bias circuit includes a gate bias circuit and a drain bias circuit; the gate bias circuit includes a first resistor, an eighth transmission line, a first capacitor and a first DC power supply, and the drain bias circuit includes a ninth transmission line, a second capacitor and a second DC power supply; one end of the first resistor is respectively connected to the input port and the input matching circuit, the other end of the first resistor is connected to one end of the eighth transmission line, the other end of the eighth transmission line is connected to one end of the first capacitor and the first DC power supply connected in parallel, and the other end of the first capacitor and the first DC power supply connected in parallel is grounded; one end of the ninth transmission line is respectively connected to the output matching circuit and the output port, the other end of the ninth transmission line is connected to one end of the second capacitor and the second DC power supply connected in parallel, and the other end of the second capacitor and the second DC power supply connected in parallel is grounded; wherein the first resistor is used to increase the out-of-band stability of the power amplifier; the eighth transmission line and the ninth transmission line are high-impedance transmission lines; the first capacitor and the second capacitor function to prevent the radio frequency signal from entering the DC power supply and causing damage to the power supply; the first DC power supply provides a gate bias voltage, i.e., a negative voltage bias, for the gate of the transistor, and the second DC power supply provides a drain bias voltage, i.e., a positive voltage bias, for the drain of the transistor.

[0014] Furthermore, the stabilization circuit includes a second resistor and a third capacitor connected in parallel.

[0015] Furthermore, the input port is connected to the input matching circuit via a first DC blocking capacitor, and the output matching circuit is connected to the output port via a second DC blocking capacitor.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0017] 1. The power amplifier of the present invention has an operating frequency of 1.4 GHz and 2.0 GHz, and an operating bandwidth of 120 MHz. No power amplification is performed outside the operating frequency band, so that spectrum resources can be better utilized.

[0018] 2. The power amplifier of the present invention can achieve a power added efficiency of more than 59% in each frequency band after adjusting the harmonic impedance.

[0019] 3. The power amplifier of the present invention can achieve a power output of more than 39dBm within the working frequency band while maintaining a gain of more than 9.5dB.

[0020] 4. The power amplifier of the present invention has simple overall processing, light weight, low processing cost, and effective use of spectrum resources, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural diagram of a dual-band matching power amplifier.

[0022] Figure 2 Schematic diagram of the input matching circuit.

[0023] Figure 3 Schematic diagram of the output matching circuit.

[0024] Figure 4 It is a structural diagram of the tuning circuit.

[0025] Figure 5 Schematic diagram of the structure of the gate bias circuit.

[0026] Figure 6 Schematic diagram of the structure of the drain bias circuit.

[0027] Figure 7 It is a structural diagram of the stabilization circuit.

[0028] Figure 8 1 is a simulation result diagram of the gain and power added efficiency of the frequency band of the dual-band matching power amplifier of this embodiment, wherein (a) is the gain and (b) is the power added efficiency.

[0029] Fig. 9 It is a simulation result diagram of the output power gain and power added efficiency at the operating frequency of the dual-band matching power amplifier of this embodiment. DETAILED DESCRIPTION

[0030] The present invention is further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0031] See also Figures 1 to 7As shown, this embodiment discloses a tuned dual-frequency matching power amplifier, including a dielectric plate (not shown) with a copper layer on the upper surface and a ground layer on the lower surface, the dielectric constant of the dielectric plate is 3.38, and the loss tangent is 0.0027; the dielectric plate is respectively provided with an input port 1, an input matching circuit, a stabilization circuit, a transistor, a tuning circuit, a DC bias circuit, an output matching circuit and an output port 2; the input port 1 is connected to the input matching circuit through a first DC blocking capacitor 3, and the input matching circuit is used to match the optimal gain input impedance of the power amplifier; the input matching circuit is connected to the stabilization circuit (composed of a second resistor 27 and a first resistor 28 connected in parallel) The invention is composed of three capacitors 28, and a stabilizing circuit is used to prevent the generation of self-excitation so as to increase the in-band stability of the power amplifier; the stabilizing circuit is connected to the gate of the transistor, the source (S) 7 of the transistor is grounded, and the drain is connected to the tuning circuit, and the harmonic impedance is adjusted to a high reflection state through the tuning circuit; the tuning circuit is connected to the output matching circuit, and the output impedance of the power amplifier is matched to the optimal efficiency and output power through the output matching circuit; the output matching circuit is connected to the output port 2 through a second DC blocking capacitor 4; the DC bias circuit is respectively connected to the gate (G) 5 and the drain (D) 6 of the transistor to provide a gate bias voltage and a drain bias voltage.

[0032] The input matching circuit comprises a first transmission line 8, a second transmission line 9, a third transmission line 10 and five open branches 11, 12, 13, 14, 15, one end of the first transmission line 8 is respectively connected to the input port 1 and an open branch, and the other end thereof is connected to one end of the second transmission line 9, the other end of the second transmission line 9 is connected to one end of the third transmission line 10, the other end of the third transmission line 10 is connected to an open branch, and two symmetrically distributed open branches are connected between each two adjacent transmission lines, and the two open branches are located on both sides of the transmission line; wherein the five open branches 11, 12, 13, 14, 15 generate two small circles symmetrical about the real axis on the Smith chart as matching points for the impedance trajectory of the input matching circuit, the admittance of the first transmission line 8 and the second transmission line 9 determines the size of the real part and the imaginary part of the matching point, and the function of the third transmission line 10 is to rotate the matching impedance trajectory as a whole on the Smith chart to the desired matching state.

[0033] The output matching circuit includes a fourth transmission line 16, a fifth transmission line 17, a sixth transmission line 18 and three open branches 19, 20 and 21. One end of the fourth transmission line 16 is connected to the tuning circuit, and the other end thereof is connected to one end of the fifth transmission line 17. The other end of the fifth transmission line 17 is connected to one end of the sixth transmission line 18. The other end of the sixth transmission line 18 is connected to an open branch, and an open branch is connected between every two adjacent transmission lines, and all the open branches are located on the same side of the transmission line; wherein the three open branches 19, 20 and 21 generate two small circles symmetrical about the real axis as matching points on the Smith chart for the impedance trajectory of the output matching circuit, and the admittance of the fifth transmission line 17 and the sixth transmission line 18 determines the size of the real part and the imaginary part of the matching point. The function of the fourth transmission line 16 is to rotate the matching impedance trajectory as a whole on the Smith chart to the desired matching state.

[0034] The tuning circuit includes a seventh transmission line 24 and four open branches. One end of the seventh transmission line 24 is respectively connected to the drain 6 of the transistor and two symmetrically distributed open branches, the two open branches are respectively the first open branch 22 and the second open branch 23, and are located on both sides of the seventh transmission line 24. The other end of the seventh transmission line 24 is respectively connected to the output matching circuit and two other symmetrically distributed open branches, the two open branches are respectively the third open branch 25 and the fourth open branch 26, and are located on both sides of the seventh transmission line 24; wherein the first open branch 22 and the second open branch 23 are used to adjust the second harmonic impedance of the two working frequencies respectively, so that the impedance is adjusted to 0, and the second harmonic impedance is in a short-circuit state; the third open branch 25, the fourth open branch 26 and the seventh transmission line 24 are used to adjust the third harmonic impedance of the two working frequencies, so that the impedance is adjusted to infinity, and the third harmonic impedance is in a short-circuit state. Finally, the harmonic impedance adjustment of this embodiment makes the power amplifier work in the Class F state.

[0035] The DC bias circuit includes a gate bias circuit and a drain bias circuit; the gate bias circuit includes a first resistor 29, an eighth transmission line 30, a first capacitor 31 and a first DC power supply 32, and the drain bias circuit includes a ninth transmission line 33, a second capacitor 34 and a second DC power supply 35; one end of the first resistor 29 is respectively connected to the input port 1 and the input matching circuit, the other end of the first resistor 29 is connected to one end of the eighth transmission line 30, the other end of the eighth transmission line 30 is connected to one end of the first capacitor 31 and the first DC power supply 32 connected in parallel, and the other end of the first capacitor 31 and the first DC power supply 32 connected in parallel is grounded; one end of the ninth transmission line 33 is respectively connected to Output matching circuit and output port 2, the other end of the ninth transmission line 33 is connected to one end of the second capacitor 34 and the second DC power supply 35 connected in parallel, and the other end of the second capacitor 34 and the second DC power supply 35 connected in parallel is grounded; wherein, the first resistor 29 is used to increase the out-of-band stability of the power amplifier; the eighth transmission line 30 and the ninth transmission line 33 are high-impedance transmission lines; the main function of the first capacitor 31 and the second capacitor 34 is to prevent the RF signal from entering the DC power supply and causing damage to the power supply; the first DC power supply 32 provides a gate bias voltage, i.e., a negative voltage bias, for the gate 5 of the transistor, and the second DC power supply 35 provides a drain bias voltage, i.e., a positive voltage bias, for the drain 6 of the transistor.

[0036] See also Figure 8 As shown in FIG. 1 , the simulation result of the gain and power added efficiency of the frequency band of the above-mentioned tuned dual-band matching power amplifier of this embodiment is shown. From the simulation results, it can be seen that when the input signal power is 28dBm, the gain in the working frequency band reaches more than 9.5dB, and the power added efficiency reaches more than 59%.

[0037] See also Fig. 9 As shown in FIG. 1 , the simulation result diagram of the output power gain and power added efficiency of the working frequency point of the above-mentioned tuned dual-frequency matching power amplifier of this embodiment is shown. From the simulation results, it can be seen that the maximum output power of 39dBm-40.5dBm can be achieved within the working frequency band.

[0038] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A tuned dual-band matching power amplifier, the power amplifier comprising a dielectric plate with a copper-clad layer on the upper surface and a ground layer on the lower surface, characterized in that: The dielectric board is respectively provided with an input port, an input matching circuit, a stabilizing circuit, a transistor, a tuning circuit, a DC bias circuit, an output matching circuit and an output port; the input port is connected to the input end of the input matching circuit, and the optimal gain input impedance of the power amplifier is matched through the input matching circuit; the output end of the input matching circuit is connected to the input end of the stabilizing circuit, and the stabilizing circuit is used to prevent the generation of self-excitation, so as to increase the in-band stability of the power amplifier; The output end of the stabilization circuit is connected to the gate of the transistor, the source of the transistor is grounded, and the drain of the transistor is connected to the input end of the tuning circuit, and the harmonic impedance is adjusted to a high reflection state through the tuning circuit; the output end of the tuning circuit is connected to the input end of the output matching circuit, and the output impedance of the power amplifier is matched to the best efficiency and output power through the output matching circuit; the output end of the output matching circuit is connected to the output port; the DC bias circuit is respectively connected to the input port and the output port to provide a gate bias voltage and a drain bias voltage; The input matching circuit comprises a first transmission line, a second transmission line, a third transmission line and five open branches, one end of the first transmission line is respectively connected to an input port and an open branch, the other end of the first transmission line is connected to one end of the second transmission line, the other end of the second transmission line is connected to one end of the third transmission line, the other end of the third transmission line is connected to the input end of the stabilization circuit, and two symmetrically distributed open branches are connected between each two adjacent transmission lines, and the two open branches are located on both sides of the transmission line; wherein the five open branches generate two small circles symmetrical about the real axis as matching points on the Smith chart for the impedance trajectory of the input matching circuit, the admittance of the first transmission line and the second transmission line determines the size of the real part and the imaginary part of the matching point, and the function of the third transmission line is to rotate the matching impedance trajectory as a whole on the Smith chart to a desired matching state; The output matching circuit comprises a fourth transmission line, a fifth transmission line, a sixth transmission line and three open branches, one end of the fourth transmission line is connected to the output end of the tuning circuit, the other end of the fourth transmission line is connected to one end of the fifth transmission line, the other end of the fifth transmission line is connected to one end of the sixth transmission line, the other end of the sixth transmission line is connected to an open branch, and an open branch is connected between every two adjacent transmission lines, and all the open branches are located on the same side of the transmission line; wherein the three open branches generate two small circles symmetrical about the real axis as matching points on the Smith chart for the impedance trajectory of the output matching circuit, the admittance of the fifth transmission line and the sixth transmission line determines the size of the real part and the imaginary part of the matching point, and the function of the fourth transmission line is to rotate the matching impedance trajectory as a whole on the Smith chart to the desired matching state.

2. A tuned dual-band matching power amplifier according to claim 1, characterized in that: The operating frequencies of the power amplifier are 1.4 GHz and 2.0 GHz. Through dual-frequency impedance matching and adjustment of harmonic impedance, it is possible to achieve a bandwidth of more than 120 MHz in each dual-frequency band, and a power output of more than 39 dBm in both dual-frequency bands, and a power added efficiency of more than 59%.

3. A tuned dual-frequency matched power amplifier according to claim 1, characterized in that: The tuning circuit comprises a seventh transmission line and four open branches, one end of the seventh transmission line is respectively connected to the drain of the transistor and two symmetrically distributed open branches, the two open branches are respectively a first open branch and a second open branch, and are located on both sides of the seventh transmission line, the other end of the seventh transmission line is respectively connected to the input end of the output matching circuit and two other symmetrically distributed open branches, the two open branches are respectively a third open branch and a fourth open branch, and are located on both sides of the seventh transmission line; wherein the first open branch and the second open branch are used to respectively adjust the second harmonic impedance of the two working frequency points, so that the impedance is adjusted to 0, and the second harmonic impedance is in a short-circuit state; the third open branch, the fourth open branch and the seventh transmission line function to adjust the third harmonic impedance of the two working frequency points, so that the impedance is adjusted to infinity, and the third harmonic impedance is in a short-circuit state.

4. The tuned dual-band matched power amplifier according to claim 1, characterized in that: The DC bias circuit includes a gate bias circuit and a drain bias circuit; the gate bias circuit includes a first resistor, an eighth transmission line, a first capacitor and a first DC power supply, and the drain bias circuit includes a ninth transmission line, a second capacitor and a second DC power supply; one end of the first resistor is respectively connected to the input port and the input end of the input matching circuit, the other end of the first resistor is connected to one end of the eighth transmission line, the other end of the eighth transmission line is connected to one end of the first capacitor and the first DC power supply connected in parallel, and the other end of the first capacitor and the first DC power supply connected in parallel is grounded; one end of the ninth transmission line is respectively connected to the output end and the output port of the output matching circuit, the other end of the ninth transmission line is connected to one end of the second capacitor and the second DC power supply connected in parallel, and the other end of the second capacitor and the second DC power supply connected in parallel is grounded; wherein the first resistor is used to increase the out-of-band stability of the power amplifier; the eighth transmission line and the ninth transmission line are high-impedance transmission lines; the first capacitor and the second capacitor are used to prevent the radio frequency signal from entering the DC power supply and causing damage to the power supply; the first DC power supply provides a gate bias voltage, i.e., a negative voltage bias, for the gate of the transistor, and the second DC power supply provides a drain bias voltage, i.e., a positive voltage bias, for the drain of the transistor.

5. The tuned dual-band matched power amplifier according to claim 1, characterized in that: The stabilization circuit includes a second resistor and a third capacitor connected in parallel.

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