Ultra-wideband high-efficiency double-path synthetic power amplifier

Abstract

The invention, which relates to the technical field of wireless communication, discloses an ultra-wideband high-efficiency dual-path synthesis power amplifier comprising a power divider, a first power amplifier branch, a second power amplifier branch, and a power combiner. The power divider is used for proportionally dividing an input radio frequency signal into two parts, and respectively inputting the two parts into the first power amplifier branch and the second power amplifier branch; the first power amplifier branch and the second power amplifier branch are consistent in circuit structure and parameter and are both used for amplifying power and realizing high-efficiency broadband; the power combiner is used for combining the radio frequency signals amplified by the first power amplifier branch and the second power amplifier branch into one and then outputting the radio frequency signals; and the power amplifier branch comprises an input matching circuit, a GaN field effect transistor and an output matching circuit which are connected in sequence. According to the invention, high-efficiency modes of various power amplifiers are combined, so that the power amplifier can realize higher output efficiency in a wider frequency band, the ultra-wideband high-efficiency double-path synthetic power amplifier with the average output efficiency of more than 65% is realized, and the relative bandwidth of the power amplifier during working is more than 70%.

Description

Technical Field

[0001] The invention relates to the technical field of wireless communications, and in particular to an ultra-wideband high-efficiency dual-path synthetic power amplifier. Background Art

[0002] In modern communication systems, the use of high-power macro base stations for large-scale signal coverage is the mainstream solution. With the development of technology, the demand for broadband high-power amplifiers is also increasing. Ultra-wideband high-power amplifiers are key research projects in the fields of electronic warfare, electromagnetic compatibility testing, and wireless communications. In order to reduce material costs and product maintenance costs, equipment manufacturers usually hope to design ultra-wideband general-purpose power amplifiers to achieve system platform integration, using a few power amplifiers to cover most communication frequency bands, which can not only reduce costs but also shorten product development cycles. In electronic warfare and radar systems, ultra-wideband high-efficiency power amplifiers are one of the key components, and they are essential for signal transmission and reception.

[0003] At present, it is difficult to realize high-efficiency power amplifiers in ultra-wideband. Domestic and foreign research on achieving high-efficiency broadband power amplifiers mostly uses power amplifier modes such as Class F and Class J, which usually use multiple quarter-wavelength lines to improve efficiency and bandwidth, which will seriously affect the complexity of the matching circuit of the power amplifier. The complex structure will also produce signal crosstalk, which will affect the application of the power amplifier in many RF systems. In addition, the existing broadband power amplifiers have a wide bandwidth but low efficiency. Within the entire bandwidth, the efficiency can only reach more than 70% at certain frequency points, and most of the power amplifiers have an efficiency of about 40% to 60%. To solve such problems, reconfigurable circuits are usually used to realize multi-stage matching of the output circuit, thereby expanding the bandwidth of the power amplifier. Since reconfigurable devices are added to the matching circuit, the complexity of the matching circuit of the power amplifier will also increase. Reconfigurable devices will introduce new losses in the power amplifier circuit. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies of the prior art and provide an ultra-wideband high-efficiency dual-channel synthetic power amplifier, which increases the average efficiency of the entire bandwidth without increasing circuit complexity, while also increasing the output power of the power amplifier.

[0005] The objective of the present invention is achieved through the following technical solutions: An ultra-wideband high-efficiency dual-channel synthetic power amplifier comprises: a power divider, a first power amplifier branch, a second power amplifier branch, and a power combiner; the power divider is used to divide an input radio frequency signal into two according to a ratio, and input the signals into the first power amplifier branch and the second power amplifier branch respectively; the first power amplifier branch and the second power amplifier branch have the same circuit structure and parameters, and are both used for power amplification and achieving high-efficiency broadband; the power combiner is used to combine the radio frequency signals amplified by the first power amplifier branch and the second power amplifier branch into one and then output; the power amplifier branch comprises an input matching circuit, a GaN field effect transistor and an output matching circuit connected in sequence; the output matching circuit adopts a sixth-order Chebyshev low-pass filter type impedance matching network, and the GaN field effect transistor uses a GaN field effect transistor in a CG2H40010F package to control the harmonics of the output matching circuit.

[0006] Furthermore, the packaging equivalent circuit of the GaN field effect tube packaged in the CG2H40010F package includes a first capacitor C1, a second capacitor C2 and a third capacitor C3 connected in parallel to the ground, and a current source terminal Z 𝑖𝑔𝑒𝑛 The first capacitor C1 is connected to the second capacitor C2, the first inductor L1 is connected in series between the first capacitor C1 and the second capacitor C2, the second inductor L2 is connected in series between the second capacitor C2 and the third capacitor C3, and the third capacitor C3 is connected to the output terminal Z p There is a third inductor L3 connected in series.

[0007] Furthermore, the sixth-order Chebyshev low-pass filter type impedance matching network includes a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6 connected in parallel to the ground, and an input terminal Z p ’ A fourth inductor L4 is connected in series between the fourth capacitor C4 and the fifth capacitor C5, a fifth inductor L5 is connected in series between the fifth capacitor C5 and the sixth capacitor C6, and a sixth inductor L6 is connected in series between the sixth capacitor C6 and the load Z 𝐿 connect.

[0008] Furthermore, the capacitances of the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are 2.2 pF, 2.2 pF and 2.4 pF respectively, and the capacitances of the fourth inductor L4, the fifth inductor L5 and the sixth inductor L6 are 2 nH, 5 nH and 5.3 nH respectively.

[0009] Furthermore, after the GaN field effect tube in the CG2H40010F package and the sixth-order Chebyshev low-pass filter type impedance matching network are connected in series, the current source terminal Z 𝑖𝑔𝑒𝑛 and load Z 𝐿 The relationship calculation formula is: ; in, is the ABCD matrix of lumped parameters, n is the total number of capacitors and inductors, is the ABCD matrix of capacitance or inductance. The ABCD matrix of capacitance is , the ABCD matrix of inductance is ,in j is an imaginary unit, ω is the frequency, C’ is the capacitance value, and L is the inductance value.

[0010] Furthermore, the gate and drain of the GaN field effect tube are respectively loaded with a gate bias voltage V Gs and drain bias voltage V Ds .

[0011] The beneficial effects of the present invention are: The present invention realizes an ultra-wideband high-efficiency dual-channel synthetic power amplifier with an average output efficiency greater than 65%, and the relative bandwidth of the power amplifier operation is greater than 70%. The high-efficiency modes of the power amplifier are combined to enable the power amplifier to achieve higher output efficiency in a wider frequency band. At the same time, the dual-channel power amplifier is used to increase the output power of the power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A structural block diagram of an ultra-wideband high-efficiency dual-path synthesis power amplifier of the present invention; Figure 2 The package equivalent circuit of the GaN field effect transistor packaged in CG2H40010F; Figure 3 The topology circuit of the prototype of Chebyshev low-pass filter; Figure 4 is a circuit structure diagram of an output matching circuit; Figure 5 for Figure 4 Output matching network distribution circuit diagram converted from output matching circuit; Figure 6 This is the simulation result diagram of the low-pass filter matching circuit; Figure 7 The Smith chart impedance trajectory of the GaN field effect transistor drain end from 1GHz to 8.4GHz; Figure 8 These are the simulation and test results of an ultra-wideband and high-efficiency dual-channel synthetic power amplifier. DETAILED DESCRIPTION

[0013] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0014] See also Figure 1-Figure 8 , the present invention provides a technical solution: An ultra-wideband high-efficiency dual-channel synthesis power amplifier, such as Figure 1 , including: a power divider, a first power amplifier branch, a second power amplifier branch, and a power combiner; the power divider is used to divide the input radio frequency signal into two in proportion, and input them into the first power amplifier branch and the second power amplifier branch respectively; the first power amplifier branch and the second power amplifier branch have the same circuit structure and parameters, and are both used for power amplification and achieving high-efficiency broadband; the power combiner is used to combine the radio frequency signals amplified by the first power amplifier branch and the second power amplifier branch into one and then output; the power amplifier branch includes an input matching circuit, a GaN field effect transistor and an output matching circuit connected in sequence; the output matching circuit adopts a sixth-order Chebyshev low-pass filter type impedance matching network, and the GaN field effect transistor uses a GaN field effect transistor in a CG2H40010F package to control the harmonics of the output matching circuit.

[0015] The gate and drain of the GaN field effect tube are respectively loaded with a gate bias voltage V Gs and drain bias voltage V Ds .

[0016] The two power amplifiers work simultaneously. Their function is to increase the output power of the entire power amplifier by adding another power amplifier circuit when the output power of one power amplifier is insufficient. The specific structure of the circuit is to first divide the RF signal into two by a Wilkinson power divider, amplify the two channels respectively, and finally combine the power through a power combiner to increase the power. This embodiment takes a GaN power amplifier circuit as an example, and the specific parameters of the other GaN power amplifier circuit are the same.

[0017] The GaN high-efficiency broadband power amplifier field effect tube in the present invention achieves the purpose of high efficiency and broadband by controlling the harmonics of the output matching circuit. According to the microwave transmission circuit theory and related knowledge, it can be known that the phase of the microwave transmission circuit usually rotates clockwise as the frequency increases. This working characteristic is similar to the frequency response characteristics of capacitors and inductors.

[0018] like Figure 2 The figure shows the package equivalent circuit of the GaN field effect tube in the CG2H40010F package, including the first capacitor C1, the second capacitor C2 and the third capacitor C3 connected in parallel to the ground, the current source terminal Z𝑖𝑔𝑒𝑛 The first capacitor C1 is connected to the second capacitor C2, the first inductor L1 is connected in series between the first capacitor C1 and the second capacitor C2, the second inductor L2 is connected in series between the second capacitor C2 and the third capacitor C3, and the third capacitor C3 is connected to the output terminal Z p In this embodiment, the capacitances of the first capacitor C1, the second capacitor C2 and the third capacitor C3 are 1.2pF, 0.25pF and 0.25pF respectively, and the capacitances of the first inductor L1, the second inductor L2 and the third inductor L3 are 0.55nH, 0.1nH and 0.1nH respectively.

[0019] according to Figure 2 The package equivalent circuit of the CG2H40010F field effect tube is given, and its high-frequency characteristics can be inferred. When the frequency reaches 5.4 GHz, the package equivalent circuit is simplified, and it can be inferred that C 2 is 0.25 pF, and its capacitive reactance value is X 𝐶2 After calculation, the value is 125Ω, and C 1 is 1.22 pF, and its capacitive reactance value can be calculated to be X 𝐶1 is 25Ω. 1 The inductance value is 0.55 nH, and the corresponding inductive reactance value at 5.4 GHz is 1.7Ω, which is very small and can be ignored. It can be inferred that the package equivalent circuit of the CG2H40010F field effect tube will show capacitive characteristics at high frequencies.

[0020] Class J power amplifiers, continuous class F power amplifiers, and continuous inverse class F power amplifiers need to control their harmonics to improve their efficiency. To achieve broadband high efficiency, it is necessary to implement one or more of the above-mentioned high-efficiency power amplifier modes within the broadband. The present invention utilizes a simple low-pass filter matching circuit to implement a variety of high-efficiency power amplifier modes to achieve a broadband effect. When implementing a class J power amplifier, its fundamental wave often needs to be matched to 50Ω, and the harmonics need to be matched to the left semicircle of the Smith chart and near the outer circle, that is, near the open short-circuit point. The second harmonic condition for implementing a continuous class F is the same as the second harmonic condition for a class J power amplifier, but it also needs to control the third harmonic to near the open circuit point. The continuous inverse class F power amplifier has the opposite harmonic condition to that of a continuous class F power amplifier, with the second harmonic being near the open circuit point and the third harmonic being near the short circuit point.

[0021] The sixth-order Chebyshev low-pass filter type impedance matching network includes a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6 connected in parallel to the ground, an input terminal Z p ’ A fourth inductor L4 is connected in series between the fourth capacitor C4 and the fifth capacitor C5, a fifth inductor L5 is connected in series between the fifth capacitor C5 and the sixth capacitor C6, and a sixth inductor L6 is connected in series between the sixth capacitor C6 and the load Z 𝐿connect.

[0022] The present invention uses a Chebyshev low-pass filter to perform output matching. Figure 3 The topological structure circuit of the prototype of the Chebyshev low-pass filter is given. It can be seen that it consists of n pairs of capacitors C and inductors L. The prototype circuit of the Chebyshev low-pass filter has an inductive output when suppressing high frequencies, which can be seen by analyzing one pair of L and C lumped components. When the frequency is high, the capacitive reactance value of the first capacitor C1 is relatively small, which will cause the components other than L1 to short-circuit, making the input impedance of the entire output matching circuit completely provided by the inductor L1, so the Chebyshev low-pass filter has an inductive output outside the band. Figure 4 The figure shows the low-pass filter matching circuit of this embodiment. The capacitances of the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are 2.2pF, 2.2pF and 2.4pF respectively, and the fourth inductor L4, the fifth inductor L5 and the sixth inductor L6 are 2nH, 5nH and 5.3nH respectively.

[0023] Since the package equivalent circuit has capacitive reactance characteristics in the high-frequency part, it can be equivalent to a capacitor; and the Chebyshev low-pass filter prototype has inductive reactance characteristics in the high-frequency part, it can be equivalent to an inductor. Since the entire path can be equivalent to an LC parallel circuit, it will definitely resonate at a certain frequency. According to the resonance theory, the parallel structure will produce a larger impedance at the resonant frequency. This phenomenon provides the conditions for the third harmonic for the Class F power amplifier, and also provides the conditions for the second harmonic for the inverse Class F power amplifier. You only need to adjust the L in the Chebyshev low-pass filter. 1 By adjusting the value, the resonance point can be controlled so that the resonance point is at the required frequency.

[0024] When the frequency exceeds the resonance point, the absolute value of the inductive reactance of the inductor is greater than the absolute value of the capacitive reactance of the capacitor. The capacitive reactance of the capacitor is less than 0, and the inductive reactance of the inductor is greater than 0. Since the two components are in parallel, the impedance value of the entire circuit is still less than 0. As the frequency increases, the impedance value will become closer and closer to the short-circuit point on the Smith chart, which provides an opportunity to achieve the third harmonic impedance condition of the inverse F class amplifier.

[0025] In summary, the Chebyshev low-pass filter circuit can achieve the harmonic conditions of inverse class F and class F power amplifiers. The low-pass broadband network can generate the fundamental and harmonic conditions required by different frequency bands at the drain end of CH2H40010F in a wider frequency band.

[0026] After the GaN field effect tube in the CG2H40010F package and the sixth-order Chebyshev low-pass filter type impedance matching network are connected in series, the impedance of the load end at the current source end after passing through the output matching circuit and the package equivalent circuit can be calculated using the characteristics of the ABCD matrix. 𝑖𝑔𝑒𝑛 and load Z 𝐿 The relationship calculation formula is: ; in, is the ABCD matrix of lumped parameters, n is the total number of capacitors and inductors, is the ABCD matrix of capacitance or inductance. The ABCD matrix of capacitance is , the ABCD matrix of inductance is ,in j is an imaginary unit, ω is the frequency, C’ is the capacitance value, and L is the inductance value.

[0027] According to the conversion formula between lumped parameters and distributed parameters, namely Richards transformation, it is a mathematical method to convert lumped parameter components into lossless transmission lines. Based on the characteristics of the transmission line, it establishes the relationship between lumped parameter components (such as inductance, capacitance) and the length and characteristic impedance of the transmission line. Using the above method, Figure 4 The low-pass filter lumped circuit in the example is converted into a distributed circuit, and the final Figure 5 Distributed circuits, Figure 5 The dashed box in the middle constitutes the output matching structure, and 2 / 10, 1.4 / 3.2, 7.4 / 4, 4.5 / 12.2, 2.8 / 10 and 2 / 4 represent the width / length of the corresponding offset, respectively, and the unit is millimeter (mm).

[0028] Figure 5 The simulation results of the low-pass filter matching circuit are as follows Figure 6 As shown, it can be seen that the drain S 11 All below -10dB. Figure 7 Figure 1 is the Smith chart impedance trajectory of the drain end from 1 GHz to 8.4 GHz. It can be seen that it can achieve class J, inverse class F and class F power amplifier modes. Figure 8 The simulation and test results of the power amplifier show that the output efficiency of the power amplifier is greater than 60% within 1.4GHz to 2.9GHz, and the average efficiency within the band is greater than 65%. It can be seen that the output efficiency at 1.8GHz and 2.7GHz is higher than that at other frequency points in the frequency band, because these two frequency points control their third harmonics, making the power amplifier work in the inverse F and F modes.

[0029] The above is only a preferred embodiment of the present invention. It should be understood that the present invention is not limited to the form disclosed herein, and should not be regarded as excluding other embodiments, but can be used in various other combinations, modifications and environments, and can be modified within the scope of the concept described herein through the above teachings or the technology or knowledge of the relevant field. The changes and modifications made by those skilled in the art shall not deviate from the spirit and scope of the present invention, and shall be within the scope of protection of the claims attached to the present invention.

Claims

1. An ultra-wideband high-efficiency dual-channel synthetic power amplifier, characterized in that: include: A power divider, a first power amplifier branch, a second power amplifier branch, and a power combiner; The power divider is used to divide the input radio frequency signal into two in proportion, and input them into the first power amplifier branch and the second power amplifier branch respectively; the first power amplifier branch and the second power amplifier branch have the same circuit structure and parameters, and are both used for power amplification and achieving high-efficiency broadband; the power combiner is used to combine the radio frequency signals amplified by the first power amplifier branch and the second power amplifier branch into one and then output; the power amplifier branch includes an input matching circuit, a GaN field effect transistor and an output matching circuit connected in sequence; the output matching circuit adopts a sixth-order Chebyshev low-pass filter type impedance matching network, and the GaN field effect transistor uses a GaN field effect transistor in a CG2H40010F package to control the harmonics of the output matching circuit.

2. The ultra-wideband high-efficiency dual-channel synthetic power amplifier according to claim 1, characterized in that: The packaging equivalent circuit of the GaN field effect tube packaged in the CG2H40010F package includes a first capacitor C1, a second capacitor C2 and a third capacitor C3 connected in parallel to the ground, a current source terminal Z 𝑖𝑔𝑒𝑛 The first capacitor C1 is connected to the second capacitor C2, the first inductor L1 is connected in series between the first capacitor C1 and the second capacitor C2, the second inductor L2 is connected in series between the second capacitor C2 and the third capacitor C3, and the third capacitor C3 is connected to the output terminal Z p There is a third inductor L3 connected in series.

3. The ultra-wideband high-efficiency dual-channel synthetic power amplifier according to claim 2, characterized in that: The sixth-order Chebyshev low-pass filter type impedance matching network includes a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6 connected in parallel to the ground, an input terminal Z p ’ A fourth inductor L4 is connected in series between the fourth capacitor C4 and the fifth capacitor C5, a fifth inductor L5 is connected in series between the fifth capacitor C5 and the sixth capacitor C6, and a sixth inductor L6 is connected in series between the sixth capacitor C6 and the load Z 𝐿 connect.

4. The ultra-wideband high-efficiency dual-channel synthetic power amplifier according to claim 3, characterized in that: The capacitances of the fourth capacitor C4, the fifth capacitor C5 and the sixth capacitor C6 are 2.2 pF, 2.2 pF and 2.4 pF respectively, and the capacitances of the fourth inductor L4, the fifth inductor L5 and the sixth inductor L6 are 2 nH, 5 nH and 5.3 nH respectively.

5. The ultra-wideband high-efficiency dual-channel synthetic power amplifier according to claim 3, characterized in that: After the GaN field effect tube of the CG2H40010F package and the sixth-order Chebyshev low-pass filter type impedance matching network are connected in series, the current source terminal Z 𝑖𝑔𝑒𝑛 and load Z 𝐿 The relationship calculation formula is: ； in, is the ABCD matrix of lumped parameters, n is the total number of capacitors and inductors, is the ABCD matrix of capacitance or inductance. The ABCD matrix of capacitance is , the ABCD matrix of inductance is ,in j is an imaginary unit, ω is the frequency, C’ is the capacitance value, and L is the inductance value.

6. The ultra-wideband high-efficiency dual-path synthetic power amplifier according to claim 1, characterized in that: The gate and drain of the GaN field effect tube are respectively loaded with a gate bias voltage V Gs and drain bias voltage V Ds .

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