Internally matched power amplifier with integrated input harmonic tuning circuit

Abstract

The application provides an inner matching power amplifier integrated with input harmonic tuning circuit, relates to the technical field of microwave integrated circuit, and integrates an input matching network, a second harmonic tuning branch, a third harmonic tuning branch, a power tube and an output matching network in a tube shell; the output end of the input matching network is connected with the gate of the power tube through a tuning node; the second harmonic tuning branch comprises a first inductor and a first capacitor in series; the third harmonic tuning branch comprises a second inductor and a second capacitor in series; the second harmonic tuning branch and the third harmonic tuning branch are both connected with the tuning node at one end and grounded at the other end; and the second harmonic tuning branch and the third harmonic tuning branch are simultaneously arranged before the gate of the power tube, so that the second harmonic component and the third harmonic component at the input end of the power tube are tuned.

Description

Technical Field

[0001] This invention relates to microwave integrated circuit technology, and more particularly to an internally matched power amplifier with an integrated input harmonic tuning circuit. Background Technology

[0002] Microwave wireless power transmission, industrial heating, and other radio frequency applications continue to evolve towards higher power and higher efficiency. As a crucial energy-consuming component in the radio frequency transmission link, the power amplifier's output power and energy conversion efficiency directly determine the overall system performance. Internally matched power amplifiers integrate the matching network within the housing, offering advantages such as small size, high consistency, and ease of use, making them the mainstream device form for high-power radio frequency systems.

[0003] To improve energy conversion efficiency, power amplifiers need to be pushed into saturation operation, which generates second and third harmonic components at the gate of the power transistor. Current harmonic handling focuses on the second harmonic, typically by placing a harmonic tuning branch at the power transistor's input to ground. The third harmonic component lacks corresponding control mechanisms, remaining at the gate and participating in the formation of the gate voltage waveform, causing the power transistor's input waveform to deviate from its design state, and DC power is consumed by this component. Furthermore, harmonic tuning branches are often arranged along the direction of RF signal transmission, sharing the same path as the fundamental frequency matching circuit and exhibiting coupling; the introduction of this branch can alter the fundamental frequency matching state.

[0004] Therefore, how to achieve the tuning of the second and third harmonics at the input end inside the tube shell, and how to separate the harmonic tuning from the fundamental frequency matching, has become a key problem that urgently needs to be solved. Summary of the Invention

[0005] This invention provides an internally matched power amplifier with an integrated input harmonic tuning circuit, which can achieve tuning of the second and third harmonics at the input end inside the casing, and separate the harmonic tuning from the fundamental frequency matching.

[0006] A first aspect of the present invention provides an internally matched power amplifier with an integrated input harmonic tuning circuit, comprising: The input matching network, second harmonic tuning stub, third harmonic tuning stub, power transistor, and output matching network are integrated within the housing. The output of the input matching network is connected to the gate of the power transistor via a tuning node; The second harmonic tuning branch includes a first inductor and a first capacitor connected in series, and the third harmonic tuning branch includes a second inductor and a second capacitor connected in series. Both the second and third harmonic tuning branches are connected at one end to the tuning node and at the other end to ground. Both the second and third harmonic tuning branches are in an open circuit state at the fundamental frequency. The drain of the power transistor is connected to the output matching network.

[0007] Optionally, in one possible implementation of the first aspect, the input matching network includes a first microstrip line, a second microstrip line, and an input T-type matching network connected in series. One end of the first microstrip line serves as the input terminal of the input matching network, one end of the second microstrip line is connected to the input terminal of the input T-type matching network, and the output terminal of the input T-type matching network serves as the output terminal of the input matching network.

[0008] Optionally, in one possible implementation of the first aspect, the input T-type matching network includes a third inductor, a fourth inductor, and a third capacitor; One end of the third inductor is connected to the second microstrip line, and the other end of the third inductor is connected to one end of the fourth inductor. The other end of the fourth inductor serves as the output of the input T-type matching network. Obtain the first node between the third inductor and the fourth inductor, with one end of the third capacitor connected to the first node and the other end of the third capacitor grounded.

[0009] Optionally, in one possible implementation of the first aspect, in the second harmonic tuning stub, one end of the first inductor is connected to the tuning node, the other end of the first inductor is connected to one end of the first capacitor, and the other end of the first capacitor is grounded. The resonant frequency of the series branch formed by the first inductor and the first capacitor is the second harmonic frequency.

[0010] Optionally, in one possible implementation of the first aspect, in the third harmonic tuning stub, one end of the second inductor is connected to the tuning node, the other end of the second inductor is connected to one end of the second capacitor, and the other end of the second capacitor is grounded; The resonant frequency of the series branch formed by the second inductor and the second capacitor is the third harmonic frequency.

[0011] Optionally, in one possible implementation of the first aspect, the connection path between the input matching network and the gate of the power transistor is used as the signal transmission path, and the second harmonic tuning branch and the third harmonic tuning branch are located on both sides of the signal transmission path, respectively.

[0012] Optionally, in one possible implementation of the first aspect, the output matching network includes an output T-type matching network, a third microstrip line, and a fourth microstrip line connected in series. The input terminal of the output T-type matching network is connected to the drain of the power transistor, and one end of the fourth microstrip line serves as the output terminal of the output matching network.

[0013] Optionally, in one possible implementation of the first aspect, the output T-type matching network includes a fifth inductor, a sixth inductor, and a fourth capacitor; One end of the fifth inductor is connected to the drain of the power transistor, the other end of the fifth inductor is connected to one end of the sixth inductor, and the other end of the sixth inductor is connected to the third microstrip line. Obtain the second node between the fifth inductor and the sixth inductor. One end of the fourth capacitor is connected to the second node, and the other end of the fourth capacitor is grounded.

[0014] Optionally, in one possible implementation of the first aspect, it also includes: Input DC blocking capacitor and gate power supply circuit; One end of the input DC blocking capacitor is connected to the RF input port, and the other end of the input DC blocking capacitor leads out to the first branch and the second branch. The first branch is connected to the gate DC power supply through the gate power supply circuit, and the second branch is connected to the input matching network. The gate power supply circuit includes a first decoupling capacitor, and a stabilizing resistor, a fifth microstrip line, and an AC-isolated inductor connected in sequence. One end of the stabilizing resistor is connected to the first branch, and one end of the AC-isolated inductor is connected to the gate DC power supply to obtain a third node between the AC-isolated inductor and the gate DC power supply. One end of the first decoupling capacitor is connected to the third node, and the other end of the first decoupling capacitor is grounded.

[0015] Optionally, in one possible implementation of the first aspect, it also includes: Output DC blocking capacitor and drain power supply circuit; The output matching network leads out a third branch and a fourth branch. The third branch is connected to the RF output port via the output DC blocking capacitor, and the fourth branch is connected to the drain DC power supply via the drain power supply circuit. The drain power supply circuit includes a sixth microstrip line and a second decoupling capacitor. One end of the sixth microstrip line is connected to the fourth branch, and the other end of the sixth microstrip line is connected to the drain DC power supply to obtain a fourth node between the sixth microstrip line and the drain DC power supply. One end of the second decoupling capacitor is connected to the fourth node, and the other end of the second decoupling capacitor is grounded. The input DC blocking capacitor, gate power supply circuit, output DC blocking capacitor, and drain power supply circuit are disposed outside the casing.

[0016] The beneficial effects of this invention are as follows: 1. This invention integrates an input matching network, a second harmonic tuning stub, a third harmonic tuning stub, a power transistor, and an output matching network within a transistor housing. The output terminal of the input matching network is connected to the gate of the power transistor via a tuning node. The second harmonic tuning stub includes a first inductor and a first capacitor connected in series, and the third harmonic tuning stub includes a second inductor and a second capacitor connected in series. Both the second and third harmonic tuning stubs are connected to the tuning node at one end and grounded at the other end. This invention achieves tuning of the second and third harmonic components at the power transistor's input terminal by simultaneously placing the second and third harmonic tuning stubs before the gate of the power transistor. Furthermore, this invention ensures that the second and third harmonic tuning stubs are open-circuited at the fundamental frequency, avoiding the influence of the harmonic tuning stubs on the fundamental frequency matching state and achieving separation of input fundamental frequency matching and harmonic tuning.

[0017] 2. In this invention, the second harmonic tuning branch and the third harmonic tuning branch are respectively set on both sides of the signal transmission path, which avoids the two branches from being close to each other in the same direction, and also avoids the branches occupying the length of the main transmission path along the signal transmission direction. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the internally matched power amplifier with an integrated input harmonic tuning circuit provided by the present invention. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein.

[0021] It should be understood that in the various embodiments of the present invention, the sequence number of each process does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0022] It should be understood that in this invention, "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or device that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or device.

[0023] It should be understood that in this invention, "multiple" refers to two or more. "And / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "Contains A, B, and C", "Contains A, B, and C" means that all three A, B, and C are contained; "Contains A, B, or C" means that one of A, B, and C is contained; "Contains A, B, and / or C" means that any one, two, or three of A, B, and C are contained.

[0024] It should be understood that in this invention, "B corresponding to A", "B corresponding to A", "A and B correspond", or "B and A correspond" means that B is associated with A, and B can be determined based on A. Determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information. Matching A and B is defined as a similarity between A and B that is greater than or equal to a preset threshold.

[0025] Depending on the context, "if" as used here can be interpreted as "when," "when," "in response to determination," or "in response to detection."

[0026] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0027] This invention provides an internally matched power amplifier with an integrated input harmonic tuning circuit, such as... Figure 1 As shown, it includes: S1 integrates the input matching network, second harmonic tuning stub, third harmonic tuning stub, power transistor, and output matching network within the housing.

[0028] It should be noted that the gate input impedance and drain output impedance of a high-power transistor are both lower than the port impedance of the RF system. The longer the connection path between the matching network and the power transistor, the more parasitic parameters accumulate along the path, and the further the impedance presented by the harmonic tuning branch deviates when it reaches the power transistor. This invention integrates the input matching network, the second harmonic tuning branch, the third harmonic tuning branch, the power transistor, and the output matching network into the transistor housing, shortening the connection length between these circuits and the power transistor, so that the impedance presented by the two harmonic tuning branches acts directly on the gate of the power transistor.

[0029] In this context, "tube shell" refers to the package housing the power transistor and its matching network; "input matching network" refers to the circuit placed before the gate of the power transistor to perform impedance transformation on the fundamental signal; "second harmonic tuning branch" refers to a branch grounded at one end to tune the second harmonic component at the gate of the power transistor; "third harmonic tuning branch" refers to a branch grounded at one end to tune the third harmonic component at the gate of the power transistor; "power transistor" refers to a transistor that amplifies radio frequency signals; "output matching network" refers to the circuit placed after the drain of the power transistor to perform impedance transformation on the fundamental signal; "second harmonic" refers to a signal component with a frequency twice that of the fundamental frequency; and "third harmonic" refers to a signal component with a frequency three times that of the fundamental frequency.

[0030] It is understandable that, such as Figure 1 As shown, an input matching network, a power transistor Q1, and an output matching network are sequentially arranged inside the transistor housing along the direction of RF signal transmission. A second harmonic tuning branch and a third harmonic tuning branch are located between the input matching network and the power transistor Q1. The RF signal enters from the input terminal of the input matching network, undergoes impedance transformation, and reaches the gate of the power transistor Q1. The power transistor Q1 amplifies the signal, outputs it from the drain, and then sends it out through the output matching network. The internally matched power amplifier provided by this invention operates at a single frequency, where the signal component is the fundamental frequency. The second and third harmonic components generated by the power transistor Q1 in saturation are tuned by the second and third harmonic tuning branches, respectively.

[0031] S2, the output of the input matching network is connected to the gate of the power transistor via a tuning node.

[0032] It should be noted that in this step, the connection point between the output of the input matching network and the gate of the power transistor is used as the tuning node. The second harmonic tuning branch and the third harmonic tuning branch are both led out from this point, so that the tuning effect of the two branches is directly applied to the gate of the power transistor, and the fundamental signal passes through this common connection point only before entering the gate.

[0033] It is understandable that, such as Figure 1As shown, there is a connection point between the output of the input matching network and the gate of the power transistor Q1. This connection point is the tuning node. One end of the second harmonic tuning branch and one end of the third harmonic tuning branch are both connected to the tuning node. The fundamental signal starts from the output of the input matching network, passes through the tuning node, and enters the gate of the power transistor Q1. The second and third harmonic components generated at the gate of the power transistor Q1 reach the tuning node in opposite directions, and then enter the second and third harmonic tuning branches, respectively.

[0034] In some embodiments, S2 includes S21-S22: S21, the input matching network includes a first microstrip line, a second microstrip line and an input T-type matching network connected in series.

[0035] It should be noted that the present invention splits the input matching network into two parts: a transmission line segment and a lumped element network. First, the first microstrip line and the second microstrip line transform the impedance on the RF input port side to an intermediate value, and then the input T-type matching network completes the transformation to the gate impedance of the power transistor.

[0036] The first microstrip line refers to the transmission line segment in the input matching network that receives the radio frequency signal; the second microstrip line refers to the transmission line segment in the input matching network located between the first microstrip line and the input T-type matching network; the input T-type matching network refers to a lumped element matching network consisting of two series-connected inductors and a capacitor connected in parallel to ground, arranged in a T-shape.

[0037] It is understandable that, such as Figure 1 As shown, the input matching network includes a first microstrip line MLIN2, a second microstrip line MLIN3, and an input T-type matching network connected in series. The RF signal first enters the first microstrip line MLIN2, then the second microstrip line MLIN3, and finally the input T-type matching network. The first microstrip line MLIN2 and the second microstrip line MLIN3 each have corresponding characteristic impedances and electrical lengths. After being cascaded, the impedance on one side of the RF input port is transformed to an intermediate value. Based on this, the input T-type matching network completes the transformation of the gate impedance to the power transistor Q1.

[0038] S22, one end of the first microstrip line serves as the input terminal of the input matching network, one end of the second microstrip line is connected to the input terminal of the input T-type matching network, and the output terminal of the input T-type matching network serves as the output terminal of the input matching network.

[0039] The input end of the input matching network refers to the end of the input matching network that receives the radio frequency signal; the output end of the input matching network refers to the end of the input matching network that sends out the radio frequency signal and is connected to the tuning node.

[0040] It is understandable that, such as Figure 1 As shown, one end of the first microstrip line MLIN2 serves as the input terminal of the input matching network and is connected to the radio frequency signal. The other end of the first microstrip line MLIN2 is connected to one end of the second microstrip line MLIN3. The other end of the second microstrip line MLIN3 is connected to the input terminal of the input T-type matching network. The output terminal of the input T-type matching network serves as the output terminal of the input matching network and is connected to the tuning node.

[0041] In some embodiments, S2 includes S23-S25: S23, the input T-type matching network includes a third inductor, a fourth inductor, and a third capacitor.

[0042] The third inductor refers to the inductor connected to the second microstrip line in the input T-type matching network; the fourth inductor refers to the inductor connected to the tuning node in the input T-type matching network; and the third capacitor refers to the capacitor connected to ground in parallel in the input T-type matching network.

[0043] It is understandable that, such as Figure 1 As shown, the input T-type matching network includes a third inductor L2, a fourth inductor L3, and a third capacitor C3. The third inductor L2 and the fourth inductor L3 are connected in series on the transmission path of the radio frequency signal, and the third capacitor C3 is connected in parallel to ground.

[0044] S24, one end of the third inductor is connected to the second microstrip line, and the other end of the third inductor is connected to one end of the fourth inductor. The other end of the fourth inductor serves as the output terminal of the input T-type matching network.

[0045] The input terminal of the input T-type matching network refers to the end of the third inductor connected to the second microstrip line; the output terminal of the input T-type matching network refers to the end of the fourth inductor connected to the tuning node.

[0046] It is understandable that, such as Figure 1 As shown, one end of the third inductor L2 is connected to the second microstrip line MLIN3, and the other end of the third inductor L2 is connected to one end of the fourth inductor L3. The other end of the fourth inductor L3 serves as the output of the input T-type matching network and is connected to the tuning node.

[0047] S25, obtain the first node between the third inductor and the fourth inductor, one end of the third capacitor is connected to the first node, and the other end of the third capacitor is grounded.

[0048] The first node refers to the connection point between the third inductor and the fourth inductor.

[0049] Understandably, the connection point between the third inductor L2 and the fourth inductor L3 is taken as the first node. One end of the third capacitor C3 is connected to the first node, and the other end of the third capacitor C3 is grounded. The radio frequency signal is transmitted to the gate of the power transistor Q1 in the order of the third inductor L2, the first node, and the fourth inductor L3. The third capacitor C3 is connected to ground in parallel at the first node, and works with the third inductor L2 and the fourth inductor L3 to complete the impedance transformation.

[0050] S3, the second harmonic tuning branch includes a first inductor and a first capacitor connected in series, the third harmonic tuning branch includes a second inductor and a second capacitor connected in series, both the second and third harmonic tuning branches are connected at one end to the tuning node and the other end is grounded, and both the second and third harmonic tuning branches are in an open circuit state at the fundamental frequency.

[0051] It should be noted that when the power transistor operates in saturation, the gate simultaneously contains the fundamental frequency component, the second harmonic component, and the third harmonic component. If left untreated, these harmonic components will participate in the formation of the gate voltage waveform, causing the power transistor's conduction state to deviate from its design state, and DC power will be consumed by the harmonic components. To remove the harmonic components, a low-impedance path to ground needs to be provided near the gate. This path must be open only to the harmonic components and cannot remove the fundamental frequency component. Therefore, this invention provides two branches, one for the second harmonic component and one for the third harmonic component. Both branches are led out from the tuning node and grounded, and both exhibit high impedance at the fundamental frequency, effectively being open-circuited. While simultaneously guiding the second and third harmonic components to ground, the fundamental signal continues to enter the power transistor's gate along the main transmission path, ensuring that the input fundamental frequency matching and harmonic tuning do not interfere with each other.

[0052] Wherein, the first inductor refers to the inductor connected to the tuning node in the second harmonic tuning segment; the first capacitor refers to the capacitor grounded in the second harmonic tuning segment; the second inductor refers to the inductor connected to the tuning node in the third harmonic tuning segment; the second capacitor refers to the capacitor grounded in the third harmonic tuning segment; the open circuit state means that the impedance presented by the segment at the corresponding frequency is greater than the impedance of the main transmission path, and the signal component flowing into the segment can be ignored.

[0053] It is understandable that, such as Figure 1As shown, the second harmonic tuning branch includes a first inductor L4 and a first capacitor C4 connected in series, and the third harmonic tuning branch includes a second inductor L5 and a second capacitor C5 connected in series. One end of each branch is connected to the tuning node, and the other end is grounded. The impedance of the branch formed by the series inductor and capacitor varies with frequency. It is capacitive below the resonant frequency, approaches zero at the resonant frequency, and is inductive above the resonant frequency. The values ​​of the first inductor L4 and the first capacitor C4 ensure that the resonant frequency of the second harmonic tuning branch falls at the second harmonic frequency, and the values ​​of the second inductor L5 and the second capacitor C5 ensure that the resonant frequency of the third harmonic tuning branch falls at the third harmonic frequency. At the fundamental frequency, both branches operate in the frequency band below their respective resonant frequencies, exhibiting capacitive high impedance and being open-circuited relative to the main transmission path. The fundamental component flowing into the two branches is relatively small. When the fundamental signal passes through the tuning node, it continues to enter the gate of the power transistor Q1. The second harmonic component generated at the gate of the power transistor Q1 enters the second harmonic tuning branch at the tuning node and is led to the ground. The third harmonic component enters the third harmonic tuning branch at the tuning node and is led to the ground.

[0054] In some embodiments, S3 includes S31-S32: S31, in the second harmonic tuning branch, one end of the first inductor is connected to the tuning node, the other end of the first inductor is connected to one end of the first capacitor, and the other end of the first capacitor is grounded.

[0055] It is understandable that one end of the first inductor L4 is connected to the tuning node, and the other end of the first inductor L4 is connected to one end of the first capacitor C4. The other end of the first capacitor C4 is grounded, and the first inductor L4 and the first capacitor C4 form a series branch between the tuning node and ground. The first inductor L4 is closer to the tuning node, and the first capacitor C4 is closer to the ground. The first capacitor C4 also blocks the DC component from flowing to the ground.

[0056] S32, the resonant frequency of the series branch formed by the first inductor and the first capacitor is the second harmonic frequency.

[0057] It should be noted that the resonant frequency of the series branch formed by the first inductor and the first capacitor is set at the second harmonic frequency, so that the branch presents low impedance at the second harmonic frequency and high impedance at the fundamental frequency, so that the second harmonic component is led to the ground and the fundamental component is not affected.

[0058] It is understandable that the resonant frequency of the series branch formed by the first inductor and the first capacitor is jointly determined by the inductance of the first inductor L4 and the capacitance of the first capacitor C4. The square root of the product of the inductance and capacitance is inversely proportional to the resonant frequency. After determining the fundamental frequency, the second harmonic frequency is twice the fundamental frequency. Based on the second harmonic frequency, the inductance of the first inductor L4 and the capacitance of the first capacitor C4 are deduced to make the series branch formed by them resonate at the second harmonic frequency. At this time, the impedance of this branch at the second harmonic frequency approaches zero, and it exhibits high capacitive impedance at the fundamental frequency.

[0059] In some embodiments, S3 includes S33-S34: S33, in the third harmonic tuning branch, one end of the second inductor is connected to the tuning node, the other end of the second inductor is connected to one end of the second capacitor, and the other end of the second capacitor is grounded.

[0060] It is understandable that one end of the second inductor L5 is connected to the tuning node, and the other end of the second inductor L5 is connected to one end of the second capacitor C5. The other end of the second capacitor C5 is grounded. The second inductor L5 and the second capacitor C5 thus form another series branch between the tuning node and ground. This series branch is connected in parallel with the series branch formed by the first inductor L4 and the first capacitor C4 at the tuning node.

[0061] S34, the resonant frequency of the series branch formed by the second inductor and the second capacitor is the third harmonic frequency.

[0062] It should be noted that the resonant frequency of the series branch formed by the second inductor and the second capacitor is set at the third harmonic frequency, so that the third harmonic component also obtains an independent low-impedance path, and the second harmonic component and the third harmonic component at the gate of the power transistor are respectively led to the ground terminal through their respective branches.

[0063] It is understandable that the third harmonic frequency is three times the fundamental frequency. Based on the third harmonic frequency, the inductance of the second inductor L5 and the capacitance of the second capacitor C5 are inferred, causing the series branch formed by them to resonate at the third harmonic frequency. At this time, the impedance of this branch at the third harmonic frequency approaches zero, while it exhibits high capacitive impedance at the fundamental frequency. Since the third harmonic frequency is higher than the second harmonic frequency, the product of the inductance and capacitance values ​​is less than the product of the first inductor L4 and the first capacitor C4.

[0064] In some embodiments, S3 includes S35: S35, the connection path between the input matching network and the gate of the power transistor is used as the signal transmission path, and the second harmonic tuning branch and the third harmonic tuning branch are located on both sides of the signal transmission path.

[0065] It should be noted that the internal layout area of ​​the tube shell is limited. If the two branches are arranged along the signal transmission direction, they will occupy the length of the main transmission path and be aligned with the input matching network. Coupled forces will occur between the branches and the input matching network, as well as between the two branches themselves, due to their similar orientation and close spacing. Therefore, this invention arranges the second harmonic tuning branch and the third harmonic tuning branch on opposite sides of the signal transmission path, extending the two branches from the tuning node in opposite directions. This is done to increase the physical spacing between the two branches and to offset the extension direction of the branches from the signal transmission direction, while not occupying the length of the main transmission path.

[0066] The signal transmission path refers to the connection path between the input matching network and the gate of the power transistor through which the radio frequency signal passes.

[0067] Understandably, the second harmonic tuning stub is located on one side of the signal transmission path, while the third harmonic tuning stub is located on the other side of the signal transmission path.

[0068] S4, the drain of the power transistor is connected to the output matching network.

[0069] It is understandable that, such as Figure 1 As shown, the drain of power transistor Q1 is connected to the output matching network. The fundamental signal amplified by power transistor Q1 enters the output matching network, is output after impedance transformation, and is then sent out. The values ​​of each component in the output matching network, along with the characteristic impedance and electrical length of each microstrip line, satisfy the impedance transformation from the drain output impedance to the RF output port at the fundamental frequency, while also taking into account the matching of the second and third harmonics at the drain of power transistor Q1.

[0070] In some embodiments, S4 includes S41-S42: S41, the output matching network includes an output T-type matching network, a third microstrip line, and a fourth microstrip line connected in series.

[0071] It should be noted that in this step, the output matching network is also divided into two parts: a lumped element network and a transmission line segment. First, the output T-type matching network raises the low impedance of the drain to an intermediate value. Then, the third and fourth microstrip lines transform the intermediate value to the impedance of the RF output port, reducing the impedance transformation span undertaken by a single part.

[0072] The output T-type matching network refers to a lumped element matching network consisting of two series-connected inductors and a capacitor connected in parallel to ground. This network is connected in a T-shape and connected to the drain of the power transistor. The third microstrip line refers to the transmission line segment in the output matching network located between the output T-type matching network and the fourth microstrip line. The fourth microstrip line refers to the transmission line segment in the output matching network that sends out the radio frequency signal.

[0073] It is understandable that, such as Figure 1 As shown, the output matching network consists of an output T-type matching network, a third microstrip line MLIN4, and a fourth microstrip line MLIN5 connected in series. The signal output from the drain of power transistor Q1 first enters the output T-type matching network, and then is sent out through the third microstrip line MLIN4 and the fourth microstrip line MLIN5. The third microstrip line MLIN4 and the fourth microstrip line MLIN5 each adopt corresponding characteristic impedances and electrical lengths. The cascaded two segments complete the transformation from the intermediate value to the impedance of the RF output port.

[0074] S42, the input terminal of the output T-type matching network is connected to the drain of the power transistor, and one end of the fourth microstrip line serves as the output terminal of the output matching network.

[0075] The output end of the output matching network refers to the end of the output matching network that sends out the radio frequency signal.

[0076] It is understandable that the input terminal of the output T-type matching network is connected to the drain of the power transistor Q1, the output terminal of the output T-type matching network is connected to one end of the third microstrip line MLIN4, the other end of the third microstrip line MLIN4 is connected to one end of the fourth microstrip line MLIN5, and the other end of the fourth microstrip line MLIN5 serves as the output terminal of the output matching network and sends out the radio frequency signal.

[0077] In some embodiments, S4 includes S43-S45: S43, the output T-type matching network includes a fifth inductor, a sixth inductor, and a fourth capacitor.

[0078] Among them, the fifth inductor refers to the inductor connected to the drain of the power transistor in the output T-type matching network; the sixth inductor refers to the inductor connected to the third microstrip line in the output T-type matching network; and the fourth capacitor refers to the capacitor connected to ground in parallel in the output T-type matching network.

[0079] It is understandable that, such as Figure 1 As shown, the fifth inductor L6 and the sixth inductor L7 are connected in series on the radio frequency signal transmission path, and the fourth capacitor C6 is connected in parallel to ground.

[0080] S44, one end of the fifth inductor is connected to the drain of the power transistor, the other end of the fifth inductor is connected to one end of the sixth inductor, and the other end of the sixth inductor is connected to the third microstrip line.

[0081] Understandably, one end of the fifth inductor L6 is connected to the drain of the power transistor Q1 and serves as the input of the output T-type matching network. The other end of the fifth inductor L6 is connected to one end of the sixth inductor L7, and the other end of the sixth inductor L7 is connected to the third microstrip line MLIN4 and serves as the output of the output T-type matching network.

[0082] The input terminal of the output T-type matching network is the end of the fifth inductor connected to the drain of the power transistor; the output terminal of the output T-type matching network is the end of the sixth inductor connected to the third microstrip line.

[0083] S45, obtain the second node between the fifth inductor and the sixth inductor, one end of the fourth capacitor is connected to the second node, and the other end of the fourth capacitor is grounded.

[0084] The second node refers to the connection point between the fifth inductor and the sixth inductor.

[0085] Understandably, one end of the fourth capacitor C6 is connected to the second node, and the other end of the fourth capacitor C6 is grounded. The radio frequency signal is transmitted to the third microstrip line MLIN4 in the order of the fifth inductor L6, the second node, and the sixth inductor L7. The fourth capacitor C6 is connected to ground in parallel at the second node, and works with the fifth inductor L6 and the sixth inductor L7 to complete the impedance transformation.

[0086] In some embodiments, the internally matched power amplifier provided by the present invention further includes an input DC blocking capacitor and a gate power supply circuit, specifically including S5-S6: S5, one end of the input DC blocking capacitor is connected to the RF input port, and the other end of the input DC blocking capacitor leads out to the first branch and the second branch. The first branch is connected to the gate DC power supply through the gate power supply circuit, and the second branch is connected to the input matching network.

[0087] It should be noted that the gate of the power transistor requires a DC bias voltage to enter the set operating state, and this DC bias voltage is provided by the gate DC power supply outside the transistor case. The DC path and the RF path converge on the gate side. Without isolation, the DC component will flow out through the RF input port, and the RF signal will also flow to the DC power supply through the gate power supply circuit. Therefore, this invention sets an input DC blocking capacitor after the RF input port, and leads two branches from the input DC blocking capacitor, one to the gate power supply circuit and the other to the input matching network. This prevents the DC component from entering the RF input port by the input DC blocking capacitor, while allowing the DC bias voltage and the RF signal to converge at the same point and be sent together to the gate of the power transistor.

[0088] Among them, the RF input port refers to the external interface through which the internal matching power amplifier receives RF signals; the input DC blocking capacitor refers to the capacitor placed after the RF input port to block the DC component; the gate power supply circuit refers to the circuit that sends the DC bias voltage provided by the gate DC power supply to the gate of the power transistor; the gate DC power supply refers to the power supply that provides the DC bias voltage to the gate of the power transistor; the first branch refers to the branch that leads to the gate power supply circuit after the input DC blocking capacitor; and the second branch refers to the branch that leads to the input matching network after the input DC blocking capacitor.

[0089] It is understandable that, such as Figure 1 As shown, one end of the input DC blocking capacitor C1 is connected to the RF input port Port1, and the other end of the input DC blocking capacitor C1 leads to a first branch and a second branch. The first branch is connected to the gate DC power supply VGS via the gate power supply circuit, and the second branch is connected to the input matching network. The RF signal enters through the RF input port Port1, passes through the input DC blocking capacitor C1, and then enters the input matching network along the second branch; the DC bias voltage provided by the gate DC power supply VGS reaches the connection point between the input DC blocking capacitor C1 and the second branch along the first branch, and then is sent to the gate of the power transistor Q1 along the second branch and through the input matching network.

[0090] S6, the gate power supply circuit includes a first decoupling capacitor, and a stabilizing resistor, a fifth microstrip line and an AC isolation inductor connected in sequence. One end of the stabilizing resistor is connected to the first branch, one end of the AC isolation inductor is connected to the gate DC power supply, and a third node is obtained between the AC isolation inductor and the gate DC power supply. One end of the first decoupling capacitor is connected to the third node, and the other end of the first decoupling capacitor is grounded.

[0091] It should be noted that the gate power supply circuit is a DC path, but it is connected to the RF path at the first branch. The RF signal will leak along this path towards the DC power supply, and noise from the DC power supply side will also enter the gate along this path. In this invention, a stabilizing resistor, a fifth microstrip line, and an AC-isolating inductor are sequentially arranged on this path. The stabilizing resistor suppresses the self-oscillation of the power transistor in the low-frequency band, the fifth microstrip line and the AC-isolating inductor block the RF signal, and a first decoupling capacitor is connected to ground near the DC power supply side of the gate to allow the DC bias voltage to pass smoothly, while confining the RF signal within the RF path and diverting noise from the DC power supply side to ground.

[0092] Among them, the stabilizing resistor is the resistor connected in series in the gate power supply circuit to suppress low-frequency self-oscillation of the power transistor; the fifth microstrip line is the transmission line segment in the gate power supply circuit located between the stabilizing resistor and the AC blocking inductor; the AC blocking inductor is the inductor connected in series in the gate power supply circuit to block the flow of radio frequency signals to the gate DC power supply; the first decoupling capacitor is the capacitor connected in parallel to ground to lead the noise on the gate DC power supply side to the ground terminal; the third node is the connection point between the AC blocking inductor and the gate DC power supply.

[0093] It is understandable that, such as Figure 1As shown, one end of the stabilizing resistor R1 is connected to the first branch, and the other end of the stabilizing resistor R1 is connected to one end of the fifth microstrip line MLIN1. The other end of the fifth microstrip line MLIN1 is connected to one end of the AC-isolated inductor L1, and the other end of the AC-isolated inductor L1 is connected to the gate DC power supply VGS. The connection point between the AC-isolated inductor L1 and the gate DC power supply VGS is taken as the third node. One end of the first decoupling capacitor C2 is connected to the third node, and the other end of the first decoupling capacitor C2 is grounded. The DC bias voltage provided by the gate DC power supply VGS passes through the AC-isolated inductor L1, the fifth microstrip line MLIN1, and the stabilizing resistor R1 to reach the first branch. The RF components leaking into this path are blocked by the AC-isolated inductor L1, and the noise on the DC power supply side is led to the ground through the first decoupling capacitor C2.

[0094] In some embodiments, the internally matched power amplifier provided by the present invention further includes an output DC blocking capacitor and a drain power supply circuit, specifically including S7-S9: S7, the output matching network leads out a third branch and a fourth branch, the third branch is connected to the RF output port through the output DC blocking capacitor, and the fourth branch is connected to the drain DC power supply through the drain power supply circuit.

[0095] It should be noted that the drain of the power transistor requires a DC supply voltage, which is provided by the external drain DC power supply. The DC path and the RF path also intersect on the output side. This invention leads out two branches after the output matching network: one leads to the RF output port through the output DC blocking capacitor, and the other leads to the drain DC power supply through the drain power supply circuit. This allows the amplified RF signal to be sent to the RF output port, while the DC supply voltage enters the drain along the other branch, and the output DC blocking capacitor blocks the DC component from flowing to the RF output port.

[0096] Among them, the RF output port refers to the external interface through which the internally matched power amplifier outputs RF signals; the output DC blocking capacitor refers to the capacitor placed before the RF output port to block the DC component; the drain power supply circuit refers to the circuit that sends the DC supply voltage provided by the drain DC power supply to the drain of the power transistor; the drain DC power supply refers to the power supply that provides the DC supply voltage to the drain of the power transistor; the third branch refers to the branch after the output matching network that leads to the output DC blocking capacitor; and the fourth branch refers to the branch after the output matching network that leads to the drain power supply circuit.

[0097] It is understandable that, such as Figure 1As shown, the output matching network leads to a third and a fourth branch. The third branch is connected to the RF output port Port2 via the output DC blocking capacitor C7, and the fourth branch is connected to the drain DC power supply VDS via the drain power supply circuit. The amplified RF signal is sent out from the output matching network and enters the third branch, then reaches the RF output port Port2 via the output DC blocking capacitor C7. The DC power supply voltage provided by the drain DC power supply VDS enters the output matching network along the fourth branch, and is then sent to the drain of the power transistor Q1 via the output matching network.

[0098] S8, the drain power supply circuit includes a sixth microstrip line and a second decoupling capacitor. One end of the sixth microstrip line is connected to the fourth branch, and the other end of the sixth microstrip line is connected to the drain DC power supply to obtain a fourth node between the sixth microstrip line and the drain DC power supply. One end of the second decoupling capacitor is connected to the fourth node, and the other end of the second decoupling capacitor is grounded.

[0099] The sixth microstrip line refers to the transmission line segment located between the fourth branch and the drain DC power supply in the drain power supply circuit; the second decoupling capacitor refers to the capacitor connected in parallel to ground to lead the noise on the drain DC power supply side to the ground; the fourth node refers to the connection point between the sixth microstrip line and the drain DC power supply.

[0100] It is understandable that, such as Figure 1 As shown, one end of the sixth microstrip line MLIN6 is connected to the fourth branch, and the other end of the sixth microstrip line MLIN6 is connected to the drain DC power supply VDS. The connection point between the sixth microstrip line MLIN6 and the drain DC power supply VDS is taken as the fourth node. One end of the second decoupling capacitor C8 is connected to the fourth node, and the other end of the second decoupling capacitor C8 is grounded. The DC supply voltage provided by the drain DC power supply VDS reaches the fourth branch through the sixth microstrip line MLIN6. RF components leaking into this path are blocked by the sixth microstrip line MLIN6, and noise on the DC power supply side is led to ground through the second decoupling capacitor C8.

[0101] S9, the input DC blocking capacitor, the gate power supply circuit, the output DC blocking capacitor, and the drain power supply circuit are disposed outside the casing.

[0102] It should be noted that the present invention places the input DC blocking capacitor, the gate power supply circuit, the output DC blocking capacitor, and the drain power supply circuit outside the tube case, so that the limited area inside the tube case is reserved for the matching network and harmonic tuning branch.

[0103] It is understandable that the input DC blocking capacitor, gate power supply circuit, output DC blocking capacitor, and drain power supply circuit are all located outside the tube housing and connected to the circuit inside the tube housing through the RF input port Port1 and the RF output port Port2.

[0104] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An internally matched power amplifier with an integrated input harmonic tuning circuit, characterized in that, include: The input matching network, second harmonic tuning stub, third harmonic tuning stub, power transistor, and output matching network are integrated within the housing. The output of the input matching network is connected to the gate of the power transistor via a tuning node; The second harmonic tuning branch includes a first inductor and a first capacitor connected in series, and the third harmonic tuning branch includes a second inductor and a second capacitor connected in series. Both the second and third harmonic tuning branches are connected at one end to the tuning node and at the other end to ground. Both the second and third harmonic tuning branches are in an open circuit state at the fundamental frequency. The drain of the power transistor is connected to the output matching network.

2. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, The input matching network includes a first microstrip line, a second microstrip line, and an input T-type matching network connected in series. One end of the first microstrip line serves as the input terminal of the input matching network, one end of the second microstrip line is connected to the input terminal of the input T-type matching network, and the output terminal of the input T-type matching network serves as the output terminal of the input matching network.

3. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 2, characterized in that, The input T-type matching network includes a third inductor, a fourth inductor, and a third capacitor; One end of the third inductor is connected to the second microstrip line, and the other end of the third inductor is connected to one end of the fourth inductor. The other end of the fourth inductor serves as the output of the input T-type matching network. Obtain the first node between the third inductor and the fourth inductor, with one end of the third capacitor connected to the first node and the other end of the third capacitor grounded.

4. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, In the second harmonic tuning branch, one end of the first inductor is connected to the tuning node, the other end of the first inductor is connected to one end of the first capacitor, and the other end of the first capacitor is grounded. The resonant frequency of the series branch formed by the first inductor and the first capacitor is the second harmonic frequency.

5. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, In the third harmonic tuning branch, one end of the second inductor is connected to the tuning node, the other end of the second inductor is connected to one end of the second capacitor, and the other end of the second capacitor is grounded. The resonant frequency of the series branch formed by the second inductor and the second capacitor is the third harmonic frequency.

6. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, The connection path between the input matching network and the gate of the power transistor is used as the signal transmission path, and the second harmonic tuning branch and the third harmonic tuning branch are located on both sides of the signal transmission path, respectively.

7. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, The output matching network includes an output T-type matching network, a third microstrip line, and a fourth microstrip line connected in series. The input terminal of the output T-type matching network is connected to the drain of the power transistor, and one end of the fourth microstrip line serves as the output terminal of the output matching network.

8. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 7, characterized in that, The output T-type matching network includes a fifth inductor, a sixth inductor, and a fourth capacitor; One end of the fifth inductor is connected to the drain of the power transistor, the other end of the fifth inductor is connected to one end of the sixth inductor, and the other end of the sixth inductor is connected to the third microstrip line. Obtain the second node between the fifth inductor and the sixth inductor. One end of the fourth capacitor is connected to the second node, and the other end of the fourth capacitor is grounded.

9. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 1, characterized in that, Also includes: Input DC blocking capacitor and gate power supply circuit; One end of the input DC blocking capacitor is connected to the RF input port, and the other end of the input DC blocking capacitor leads out to the first branch and the second branch. The first branch is connected to the gate DC power supply through the gate power supply circuit, and the second branch is connected to the input matching network. The gate power supply circuit includes a first decoupling capacitor, and a stabilizing resistor, a fifth microstrip line, and an AC-isolated inductor connected in sequence. One end of the stabilizing resistor is connected to the first branch, and one end of the AC-isolated inductor is connected to the gate DC power supply to obtain a third node between the AC-isolated inductor and the gate DC power supply. One end of the first decoupling capacitor is connected to the third node, and the other end of the first decoupling capacitor is grounded.

10. The internally matched power amplifier with integrated input harmonic tuning circuit according to claim 9, characterized in that, Also includes: Output DC blocking capacitor and drain power supply circuit; The output matching network leads out a third branch and a fourth branch. The third branch is connected to the RF output port via the output DC blocking capacitor, and the fourth branch is connected to the drain DC power supply via the drain power supply circuit. The drain power supply circuit includes a sixth microstrip line and a second decoupling capacitor. One end of the sixth microstrip line is connected to the fourth branch, and the other end of the sixth microstrip line is connected to the drain DC power supply to obtain a fourth node between the sixth microstrip line and the drain DC power supply. One end of the second decoupling capacitor is connected to the fourth node, and the other end of the second decoupling capacitor is grounded. The input DC blocking capacitor, gate power supply circuit, output DC blocking capacitor, and drain power supply circuit are disposed outside the casing.

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