A radio frequency filter circuit and a method of adjusting a radio frequency filter circuit

Abstract

The embodiment of the present application provides a kind of radio frequency filter circuit and a kind of radio frequency filter circuit adjusting method, the radio frequency filter circuit includes: frequency selective network and at least one inductive adjusting circuit;Each described inductive adjusting circuit is connected between the two via holes of the first inductance or the second inductance;The inductive adjusting circuit is on, and the inductance of the first inductance or the second inductance is reduced;The inductive adjusting circuit is off, and the inductance of the first inductance or the second inductance is increased.According to the embodiment of the present application, microstrip line inductance solves the problem that ordinary wire winding inductance coil is not conducive to fixing, inductance is easily affected by vibration, which may cause the curve of filter network to deteriorate.By switching different on-off combination modes of inductive adjusting circuit, multiple frequency selective network combinations can be achieved, which can improve the debugging accuracy and batch production consistency of filter network.

Description

Technical Field

[0001] This invention relates to the field of electronic technology, and in particular to a radio frequency (RF) filter circuit, a method for adjusting the RF filter circuit, a circuit board structure, and a semiconductor device. Background Technology

[0002] With the rapid development of RF power supply and RF communication applications, higher requirements have been placed on the overall output power performance of RF power supplies, communication solid-state amplifiers, and other equipment, especially in terms of signal-to-noise ratio and harmonic suppression. This, in turn, places higher demands on the debugging accuracy and consistency of the installation process of the RF filtering devices inside the RF power supply. Summary of the Invention

[0003] In view of the above problems, embodiments of the present invention are proposed to provide an RF filter circuit, a corresponding adjustment method for the RF filter circuit, a circuit board structure, and a semiconductor device that overcome or at least partially solve the above problems.

[0004] To address the above problems, embodiments of the present invention disclose an radio frequency filtering circuit, comprising: a frequency selection network and at least one inductor adjustment circuit;

[0005] The frequency selection network includes a first inductor, a second inductor, a first capacitor, a second capacitor, and a third capacitor;

[0006] One end of the first capacitor is connected to the input terminal and the radio frequency input terminal of the first inductor, and the other end is grounded;

[0007] The first inductor is connected in series with the second inductor;

[0008] One end of the second capacitor is connected between the first inductor and the second inductor, and the other end is grounded;

[0009] One end of the third capacitor is connected to the output terminal and the RF output terminal of the second inductor, and the other end is grounded; the first inductor and the second inductor are microstrip line inductors, and each microstrip line segment is connected based on vias;

[0010] Each of the aforementioned inductor adjustment circuits is connected between two vias of the first inductor or the second inductor; when the inductor adjustment circuit is turned on, it reduces the inductance of the first inductor or the second inductor; when the inductor adjustment circuit is turned off, it increases the inductance of the first inductor or the second inductor.

[0011] Optionally, it further includes: a capacitor adjustment circuit; the frequency selection network further includes: a fourth capacitor;

[0012] One end of the fourth capacitor is connected to the capacitor adjustment circuit, and the other end is grounded;

[0013] One end of the capacitor adjustment circuit is connected between the first inductor and the second inductor, and the other end is connected to the fourth capacitor; when the capacitor adjustment circuit is turned on, the fourth capacitor is connected to the frequency selection network; when the capacitor adjustment circuit is turned off, the fourth capacitor is disconnected from the frequency selection network.

[0014] Optionally,

[0015] The inductor adjustment circuit includes a first MOSFET, a first resistor, and a fifth capacitor;

[0016] The drain (D) of the first MOSFET is connected to a via of the first inductor or the second inductor, the gate (G) is connected to the first resistor, and the source (S) is connected to the fifth capacitor and the control signal output terminal.

[0017] One end of the first resistor is connected to the first MOSFET, and the other end is connected to the control signal input terminal;

[0018] One end of the fifth capacitor is connected to the first MOS transistor and the control signal output terminal, and the other end is connected to another via of the first inductor or the second inductor.

[0019] When the first MOSFET is turned on according to the received control signal, the inductance of the first inductor or the second inductor is reduced; when the first MOSFET is turned off according to the received control signal, the inductance of the first inductor or the second inductor is increased.

[0020] Optionally,

[0021] The number of inductor adjustment circuits connected to the first inductor is the same as the number of inductor adjustment circuits connected to the second inductor;

[0022] When a first number of the inductor adjustment circuits connected to the first inductor are turned on, a first number of the inductor adjustment circuits connected to the second inductor are also turned on.

[0023] When the second number of inductor adjustment circuits connected to the first inductor are disconnected, the second number of inductor adjustment circuits connected to the second inductor are also disconnected.

[0024] Optionally,

[0025] The capacitor regulation circuit includes a second MOSFET and a second resistor;

[0026] The drain (D) of the second MOSFET is connected between the first inductor and the second inductor, the gate (G) is connected to the second resistor, and the source (S) is connected to the fourth capacitor and the control signal output terminal.

[0027] One end of the second resistor is connected to the second MOSFET, and the other end is connected to the control signal input terminal;

[0028] When the second MOS transistor is turned on according to the received control signal, the fourth capacitor is connected to the frequency selection network; when the second MOS transistor is turned off according to the received control signal, the fourth capacitor is disconnected from the frequency selection network.

[0029] Optionally, the first capacitor, the second capacitor, the third capacitor, and the fourth capacitor are all adjustable capacitors, the fifth capacitor is a fixed capacitor, and the dielectric of the adjustable capacitor is polytetrafluoroethylene sheet.

[0030] Optionally, the microstrip lines of the first inductor and the microstrip lines of the second inductor are arranged in different directions.

[0031] This invention also discloses an adjustment method for an RF filter circuit, applied to the RF filter circuit described above, the method comprising:

[0032] Determine the target suppression frequency, and based on the target suppression frequency, determine the target inductance parameters and target capacitance parameters required for the RF filter circuit;

[0033] Based on the target inductance parameters, adjust the shorting method of adjacent microstrip segments in the first inductor or the second inductor; and / or, based on the target inductance parameters, adjust the on / off combination of each inductor adjustment circuit.

[0034] Adjust the number of wafer dielectrics in the first, second, and third capacitors according to the target capacitance parameters; and / or control the on / off state of the capacitance adjustment circuit according to the target capacitance parameters.

[0035] This invention also discloses a circuit board structure, including the radio frequency filter circuit described above, wherein the radio frequency filter circuit is connected to a heat sink.

[0036] This invention also discloses a semiconductor process apparatus, including a radio frequency (RF) filter device, wherein the RF filter device employs the RF filter circuit described above.

[0037] The embodiments of the present invention have the following advantages:

[0038] In this embodiment of the invention, the RF filter circuit includes a frequency selection network and at least one inductor adjustment circuit. The first and second inductors in the frequency selection network are microstrip line inductors, and each microstrip line segment is connected vias. Each inductor adjustment circuit is connected between two vias of the first or second inductor. The inductance of the first or second inductor can be adjusted according to the on / off state of the inductor adjustment circuit. Using this method, the microstrip line inductor solves the problems of ordinary wire-wound inductors being difficult to fix, and their inductance being easily affected by vibration, potentially leading to a deterioration in the filter network curve. By switching different on / off combinations of the inductor adjustment circuit, multiple frequency selection network combinations can be achieved, improving the debugging accuracy and mass production consistency of the filter network. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of an existing combination of wound inductors and capacitors;

[0040] Figure 2 This is a structural block diagram of a radio frequency filter circuit according to an embodiment of the present invention;

[0041] Figure 3 This is a structural block diagram of another radio frequency filter circuit according to an embodiment of the present invention;

[0042] Figure 4 This is a circuit diagram of a radio frequency filtering circuit according to an embodiment of the present invention;

[0043] Figure 5 This is a flowchart illustrating the steps of an adjustment method for a radio frequency filter circuit according to an embodiment of the present invention.

[0044] Figure 6 This is a schematic diagram of a filled adjustable capacitor according to an embodiment of the present invention;

[0045] Figure 7 Is with Figure 4 Corresponding circuit board structure diagram;

[0046] Figure 8 Is with Figure 4 Axial view of the corresponding circuit board structure;

[0047] Figure 9 This is a side view schematic diagram of a circuit board structure according to an embodiment of the present invention. Detailed Implementation

[0048] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. 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 are within the scope of protection of the present invention.

[0049] Radio frequency (RF) filtering devices are mainly used inside RF power supplies, communication solid-state amplifiers, and other equipment to suppress harmonics at the RF power output end and improve the output spectrum; and to filter out out-of-band interference and noise at the front end of RF modules to meet the signal-to-noise ratio requirements of RF systems and communication protocols.

[0050] With the rapid development of RF power supply and RF communication fields, higher requirements have been placed on the debugging accuracy and installation process consistency of RF filtering devices inside RF power supplies. The debugging accuracy and installation process consistency of RF filtering devices will have the following impacts: when the main power signal is transmitted to the lower-level matching device, will the harmonic components affect the tuning of the lower-level matching device; or when the main power signal is transmitted to the front end of the lower-level module, can it be guaranteed that its noise will not interfere with the lower-level module?

[0051] Reference Figure 1 The diagram shows a conventional combination of wound inductors and capacitors, including a filter network composed of capacitors C1, C2, and C3 and inductors L1 and L2. The working principle of this filter network is to calculate the corresponding inductor and capacitor values ​​based on the frequency range to be suppressed. The inductance of inductors L1 and L2 is determined by the outer diameter of the enameled wire, the inner diameter of the coil, and the number of turns. During filter network debugging, the tightness or looseness of the turns in inductors L1 and L2 can be adjusted to regulate the inductance. The capacitance values ​​of capacitors C1, C2, and C3 can be obtained by combining existing capacitors based on the calculated capacitance values ​​in the filter network to achieve values ​​close to the calculated values.

[0052] The above combination method has at least the following disadvantages:

[0053] 1. Combined filter networks require a large space, and the inductor coils are not easy to fix, and the inductance is easily affected by vibration.

[0054] 2. During the debugging of the filter network, it is difficult for different people to maintain a consistent level of tightness or looseness in adjusting the inductor coil, resulting in slight differences in the curves of each filter network.

[0055] 3. Filtering networks can only suppress fixed frequency bands. If harmonics in other frequency bands need to be filtered out, another filtering network needs to be added, which results in a large space occupation and is not conducive to installation.

[0056] 4. Combining existing capacitor specifications can only approximate the calculated value as closely as possible, but cannot actually achieve the calculated value. This results in a certain fluctuation range in the filter network, which is not conducive to subsequent adjustments.

[0057] 5. When winding inductor coils, the looseness or tightness of the coil's outer diameter is a discrete factor, resulting in differences in the filter network curves within the same batch. Integrating the filter network into the complete system will affect the consistency of the RF power supply specifications.

[0058] 6. For low-power applications, surface-mount adjustable capacitors can be used to replace capacitors C1, C2, and C3. However, for power ratings above 1000W, high-voltage adjustable capacitors soldered onto the circuit board / printed board are specialized products that are difficult to select and procure, and are also very expensive.

[0059] Based on this, the present invention provides an RF filter circuit and a corresponding adjustment method for the RF filter circuit, a circuit board structure, and a semiconductor device.

[0060] One of the core concepts of this invention is that the RF filter circuit includes a frequency selection network and at least one inductor adjustment circuit. The first and second inductors in the frequency selection network are microstrip line inductors, and each microstrip line segment is connected vias. Each inductor adjustment circuit is connected between two vias of the first or second inductor. The inductance of the first or second inductor can be adjusted according to the on / off state of the inductor adjustment circuit. Using this method, the microstrip line inductor solves the problems of ordinary wire-wound inductors being difficult to fix, and their inductance being easily affected by vibration, potentially leading to a deterioration in the filter network curve. By switching different on / off combinations of the inductor adjustment circuit, multiple frequency selection network combinations can be achieved, improving the debugging accuracy and mass production consistency of the filter network.

[0061] Reference Figure 2 The diagram shows a structural block diagram of a radio frequency filter circuit according to an embodiment of the present invention. The radio frequency filter circuit 201 includes: a frequency selection network 2011 and at least one inductor adjustment circuit 2012.

[0062] The frequency selection network 2011 includes a first inductor, a second inductor, a first capacitor, a second capacitor, and a third capacitor.

[0063] One end of the first capacitor is connected to the input terminal and the RF input terminal of the first inductor, and the other end is grounded.

[0064] The first inductor is connected in series with the second inductor.

[0065] One end of the second capacitor is connected between the first inductor and the second inductor, and the other end is grounded.

[0066] One end of the third capacitor is connected to the output terminal and the RF output terminal of the second inductor, and the other end is grounded.

[0067] The first and second inductors are microstrip line inductors, and each microstrip line segment is connected based on vias.

[0068] Each inductor adjustment circuit is connected between two vias of the first inductor or the second inductor.

[0069] When the inductance adjustment circuit is on, the inductance of the first inductor or the second inductor is reduced; when the inductance adjustment circuit is off, the inductance of the first inductor or the second inductor is increased.

[0070] In the radio frequency filtering circuit of this invention embodiment, the first inductor and the second inductor in the frequency selection network are both set as microstrip line inductors. Each microstrip line segment can be connected based on vias, which solves the problem that ordinary wire-wound inductors are not easy to fix, and the inductance is easily affected by vibration, which may lead to a deterioration of the filtering network curve.

[0071] The inductor adjustment circuit is connected between two vias of the first or second inductor in the frequency selection network to adjust the inductance of the first or second inductor. When the inductor adjustment circuit switches between different on / off combinations, the same number of circuit components can be used to form filter networks for different frequency bands.

[0072] In summary, in this embodiment of the invention, the RF filter circuit includes a frequency selection network and at least one inductor adjustment circuit. The first and second inductors in the frequency selection network are microstrip line inductors, and each microstrip line segment is connected vias. Each inductor adjustment circuit is connected between two vias of the first or second inductor. The inductance of the first or second inductor can be adjusted according to the on / off state of the inductor adjustment circuit. Using this method, the microstrip line inductor solves the problems of ordinary wire-wound inductors being difficult to fix, and their inductance being easily affected by vibration, potentially leading to a deterioration in the filter network curve. By switching different on / off combinations of the inductor adjustment circuit, multiple frequency selection network combinations can be achieved, improving the debugging accuracy and mass production consistency of the filter network.

[0073] Reference Figure 3 The diagram shows a structural block diagram of another radio frequency filter circuit according to an embodiment of the present invention. The radio frequency filter circuit 301 includes: a frequency selection network 3011, at least one inductor adjustment circuit 3012 and a capacitor adjustment circuit 3013.

[0074] The frequency selection network includes a first inductor, a second inductor, a first capacitor, a second capacitor, and a third capacitor. The frequency selection network also includes a fourth capacitor.

[0075] One end of the first capacitor is connected to the input terminal and the RF input terminal of the first inductor, and the other end is grounded.

[0076] The first inductor is connected in series with the second inductor.

[0077] One end of the second capacitor is connected between the first inductor and the second inductor, and the other end is grounded.

[0078] One end of the third capacitor is connected to the output terminal and the RF output terminal of the second inductor, and the other end is grounded.

[0079] One end of the fourth capacitor is connected to the capacitor regulation circuit, and the other end is grounded.

[0080] The first and second inductors are microstrip line inductors, and each microstrip line segment is connected based on vias.

[0081] Each inductor adjustment circuit is connected between two vias of the first inductor or the second inductor.

[0082] One end of the capacitor regulation circuit is connected between the first inductor and the second inductor, and the other end is connected to the fourth capacitor.

[0083] When the inductance adjustment circuit is on, the inductance of the first inductor or the second inductor is reduced; when the inductance adjustment circuit is off, the inductance of the first inductor or the second inductor is increased.

[0084] When the capacitor regulation circuit is on, the fourth capacitor is connected to the frequency selection network; when the capacitor regulation circuit is off, the fourth capacitor is disconnected from the frequency selection network.

[0085] In the radio frequency filtering circuit of this embodiment of the invention, one end of the capacitor adjustment circuit is connected between the first inductor and the second inductor connected in series, and the other end is connected to the fourth capacitor. The capacitor adjustment circuit is used to control the connection of the fourth capacitor to the frequency selection network and can adjust the capacitance value in the frequency selection network.

[0086] In an optional embodiment of the present invention, the inductor adjustment circuit includes a first MOSFET, a first resistor, and a fifth capacitor.

[0087] The drain (D) of the first MOSFET is connected to a via of either the first or second inductor, the gate (G) is connected to the first resistor, and the source (S) is connected to the fifth capacitor and the control signal output terminal.

[0088] One end of the first resistor is connected to the first MOSFET, and the other end is connected to the control signal input terminal.

[0089] One end of the fifth capacitor is connected to the first MOSFET and the control signal output terminal, and the other end is connected to another via of the first inductor or the second inductor.

[0090] When the first MOSFET is turned on according to the received control signal, the inductance of the first inductor or the second inductor is reduced; when the first MOSFET is turned off according to the received control signal, the inductance of the first inductor or the second inductor is increased.

[0091] A MOSFET switching circuit is a circuit constructed using the principle that the gate (G) of a MOSFET controls the on / off state of its source (S) and drain (D). By switching the first MOSFET in different inductor adjustment circuits with different on / off combinations, different frequency selection network combinations are achieved.

[0092] In an optional embodiment of the present invention, the number of inductance adjustment circuits connected to the first inductor is the same as the number of inductance adjustment circuits connected to the second inductor.

[0093] When a first number of inductor adjustment circuits connected to the first inductor are turned on, a first number of inductor adjustment circuits connected to the second inductor are turned on; when a second number of inductor adjustment circuits connected to the first inductor are turned off, a second number of inductor adjustment circuits connected to the second inductor are turned off.

[0094] For example, the inductance adjustment circuit connected to the first inductor is K1, and the inductance adjustment circuit connected to the second inductor is K2. The on / off state of K1 and K2 is controlled by control signal 1. When control signal 1 is a conduction signal, K1 and K2 circuits can be turned on simultaneously; when control signal 1 is a disconnection signal, K1 and K2 circuits can be turned off simultaneously.

[0095] In an optional embodiment of the present invention, the capacitor regulation circuit includes a second MOSFET and a second resistor.

[0096] The drain (D) of the second MOSFET is connected between the first and second inductors, the gate (G) is connected to the second resistor, and the source (S) is connected to the fourth capacitor and the control signal output terminal.

[0097] One end of the second resistor is connected to the second MOSFET, and the other end is connected to the control signal input terminal.

[0098] When the second MOSFET is turned on according to the received control signal, the fourth capacitor is connected to the frequency selection network; when the second MOSFET is turned off according to the received control signal, the fourth capacitor is disconnected from the frequency selection network.

[0099] In this embodiment of the invention, the second MOS transistor is used to control the fourth capacitor to connect to the frequency selection network.

[0100] In an optional embodiment of the present invention, the first capacitor, the second capacitor, the third capacitor and the fourth capacitor are all adjustable capacitors, the fifth capacitor is a fixed capacitor, and the dielectric of the adjustable capacitor is a polytetrafluoroethylene sheet.

[0101] The capacitance value of the capacitor element can be adjusted by increasing or decreasing the number of PTFE sheets. By changing the stacking amount of PTFE sheets as the filling medium, the required capacitance value in the filter network can be precisely achieved, while saving procurement costs. This can improve the debugging accuracy of the filter network and the consistency of mass production, and reduce capacitor procurement costs.

[0102] In an optional embodiment of the present invention, the microstrip segments of the first inductor and the microstrip segments of the second inductor are arranged in different directions.

[0103] Inductors are drawn on the circuit board using segmented microstrip lines, which reduces installation space and internal interference. When designing the circuit board, the mutual inductance interference between adjacent inductors can be reduced by setting the routing direction of the microstrip segments differently. For example, each microstrip segment of inductor L1 is tilted to the left, and each microstrip segment of inductor L2 is tilted to the right. This layout reduces mutual magnetic field interference between inductors L1 and L2.

[0104] In an optional embodiment of the present invention, when adjusting the inductance, it can be adjusted by shorting the vias between adjacent microstrip segments of the first or second inductor. This solves the problem that different personnel are unlikely to maintain consistency in adjusting the tightness or looseness of the inductor coils, resulting in differences in the performance of various RF filtering devices.

[0105] In an optional embodiment of the present invention, the first capacitor, the second capacitor, and the third capacitor are mounted on the same side of the circuit board, and the grounding loop between each capacitor is shortened, which is beneficial to the out-of-band frequency suppression of the filter network.

[0106] To enable those skilled in the art to better understand the radio frequency filtering circuit of the embodiments of the present invention, an example is provided below:

[0107] Reference Figure 4 The diagram shown is a circuit diagram of an radio frequency filtering circuit according to an embodiment of the present invention, specifically including:

[0108] The frequency selection network includes inductor L1, inductor L2, capacitor C1, capacitor C2, and capacitor C3.

[0109] In this configuration, one end of capacitor C1 is connected to the input and RF input terminals of inductor L1, and the other end is grounded; inductor L1 and inductor L2 are connected in series; one end of capacitor C2 is connected between inductor L1 and inductor L2, and the other end is grounded; one end of capacitor C3 is connected to the output and RF output terminals of inductor L2, and the other end is grounded; inductors L1 and L2 are microstrip line inductors, and each microstrip line segment is connected based on vias.

[0110] It also includes: inductance adjustment circuit K1, inductance adjustment circuit K2, inductance adjustment circuit K4 and inductance adjustment circuit K5.

[0111] The inductor adjustment circuit K1 includes a MOSFET Q1, a resistor R1, and a capacitor C4. The drain (D) of the MOSFET Q1 is connected to a via of the inductor L1, the gate (G) is connected to the resistor R1, and the source (S) is connected to the capacitor C4 and the control signal output terminal (corresponding to the negative control signal in the diagram). One end of the resistor R1 is connected to the MOSFET Q1, and the other end is connected to the input terminal of control signal 1. One end of the capacitor C4 is connected to the MOSFET Q1 and the control signal output terminal, and the other end is connected to another via of the inductor L1.

[0112] The inductor adjustment circuit K2 includes a MOSFET Q2, a resistor R2, and a capacitor C5. The drain (D) of the MOSFET Q2 is connected to a via of the inductor L1, the gate (G) is connected to the resistor R2, and the source (S) is connected to the capacitor C5 and the control signal output terminal (corresponding to the negative control signal in the diagram). One end of the resistor R2 is connected to the MOSFET Q2, and the other end is connected to the input terminal of control signal 2. One end of the capacitor C5 is connected to the MOSFET Q2 and the control signal output terminal, and the other end is connected to another via of the inductor L1.

[0113] The inductor adjustment circuit K4 includes a MOSFET Q4, a resistor R4, and a capacitor C6. The drain (D) of the MOSFET Q4 is connected to a via of the inductor L2, the gate (G) is connected to the resistor R4, and the source (S) is connected to the capacitor C6 and the control signal output terminal (corresponding to the negative control signal in the diagram). One end of the resistor R4 is connected to the MOSFET Q4, and the other end is connected to the input terminal of control signal 2. One end of the capacitor C6 is connected to the MOSFET Q4 and the control signal output terminal, and the other end is connected to another via of the inductor L2.

[0114] The inductor adjustment circuit K5 includes a MOSFET Q5, a resistor R5, and a capacitor C8. The drain (D) of the MOSFET Q5 is connected to a via of the inductor L2, the gate (G) is connected to the resistor R5, and the source (S) is connected to the capacitor C8 and the control signal output terminal (corresponding to the negative control signal in the diagram). One end of the resistor R5 is connected to the MOSFET Q5, and the other end is connected to the input terminal of control signal 2. One end of the capacitor C8 is connected to the MOSFET Q5 and the control signal output terminal, and the other end is connected to another via of the inductor L2.

[0115] The RF filter circuit also includes: capacitor adjustment circuit K3; the frequency selection network also includes: capacitor C2-1.

[0116] The capacitor regulation circuit K3 includes a MOSFET Q3 and a resistor R3. The drain of the MOSFET Q3 is connected between inductors L1 and L2, the gate is connected to the resistor R3, and the source is connected to the capacitor C2-1 and the control signal output terminal. One end of the resistor R3 is connected to the MOSFET Q3, and the other end is connected to the control signal 2 input terminal.

[0117] One end of capacitor C2-1 is connected to MOSFET Q3, and the other end is grounded.

[0118] Capacitors C1, C2, C3, and C2-1 are adjustable capacitors, while capacitors C4, C5, C6, and C8 are fixed capacitors with larger capacitance values.

[0119] In addition, the microstrip lines of inductor L1 and inductor L2 are arranged in different directions.

[0120] The specific workflow of the aforementioned RF filtering circuit includes:

[0121] Control signal 1 controls the opening and closing of inductor adjustment circuits K1 and K4, thereby simultaneously changing the inductance of inductors L1 and L2; control signal 2 controls the opening and closing of inductor adjustment circuits K2 and K5, as well as capacitor adjustment circuit K3, thereby simultaneously changing the inductance of inductors L1 and L2, and controlling whether capacitor C2-1 is connected to the frequency selection network.

[0122] Multiple frequency bands can be selected by using various on / off combinations of inductor or capacitor adjustment circuits. Specifically, there are four combinations: control signal 1 is connected and control signal 2 is zero; control signal 2 is connected and control signal 1 is zero; control signals 1 and 2 are both zero; and control signals 1 and 2 are both connected.

[0123] Capacitors C4, C5, C6, and C8 provide an RF path when their corresponding MOSFETs are turned on, while simultaneously blocking either control signal 1 or control signal 2 from entering the frequency selection network. Resistors R1, R2, R3, R4, and R5 are current-limiting resistors. In practical implementation, the actual values ​​of inductors L1 and L2 and capacitors C1, C2, and C3 required by the RF filter circuit can be calculated through simulation based on the desired frequency suppression range.

[0124] The frequency selection network of this invention is composed of a tunable microstrip line inductor and a filled tunable capacitor. The inductance of inductors L1 and L2 can be changed using the switching characteristics of MOSFETs, and the connection of capacitor C2-1 to the frequency selection network can be controlled.

[0125] In summary, in this embodiment of the invention, the RF filter circuit includes a frequency selection network and at least one inductor adjustment circuit. The first and second inductors in the frequency selection network are microstrip line inductors, and each microstrip line segment is connected vias. Each inductor adjustment circuit is connected between two vias of the first or second inductor. The inductance of the first or second inductor can be adjusted according to the on / off state of the inductor adjustment circuit. Using this method, the microstrip line inductor solves the problems of ordinary wire-wound inductors being difficult to fix, and their inductance being easily affected by vibration, potentially leading to a deterioration in the filter network curve. By switching different on / off combinations of the inductor adjustment circuit, multiple frequency selection network combinations can be achieved, improving the debugging accuracy and mass production consistency of the filter network.

[0126] Reference Figure 5 The diagram illustrates a flowchart of the adjustment method for an RF filter circuit according to an embodiment of the present invention. Applied to any of the RF filter circuits described above, the method may specifically include the following steps:

[0127] Step 501: Determine the target suppression frequency, and determine the target inductance parameters and target capacitance parameters required by the RF filter circuit based on the target suppression frequency.

[0128] In this embodiment of the invention, the target suppression frequency that needs to be suppressed can be determined, and the target inductance parameters and target capacitance parameters that the radio frequency filter circuit needs to achieve to meet the target suppression frequency requirement can be determined.

[0129] Step 502: Adjust the short-circuiting method of adjacent microstrip segments in the first inductor or the second inductor according to the target inductor parameters; and / or, adjust the on / off combination of each inductor adjustment circuit according to the target inductor parameters.

[0130] For the RF filter circuit designed above, the inductance in the frequency selection network can be adjusted by shorting the adjacent microstrip segments between the first inductor or the second inductor, or by adjusting the on / off combinations of the various inductor adjustment circuits.

[0131] In one example, the layout of the microstrip line inductor on the circuit board can be determined by the following steps:

[0132] The process begins by determining the current flowing through the frequency-selective network and obtaining the trace width for its routing. Based on the current and trace width, and using a pre-defined current design rule lookup table, the microstrip line width of the microstrip inductor is determined. According to the target suppression frequency, the target inductor parameters required for the RF filter circuit are determined using simulation software. Based on the target inductor parameters and microstrip line width, and using a pre-defined microstrip inductor calculation formula, the microstrip line length is determined. Based on the microstrip line length and the spatial structure of the circuit board, the microstrip line is divided into multiple microstrip segments. These segments are then connected vias and routed on the circuit board. After routing, the actual inductance parameters of the microstrip inductor are determined, including via inductance parameters. Based on the difference between the target and actual inductance parameters, the shorting method of the microstrip line segments of the microstrip inductor is adjusted.

[0133] In practice, the current passing through the frequency selection network can be calculated based on the required RF power and load impedance of the RF power supply. The microstrip width of the microstrip inductor can then be determined according to the PCB (Printed Circuit Board) trace width and current design rule reference table.

[0134] Based on the frequency range to be suppressed, the required inductance value for each microstrip inductor is calculated using simulation software. The length of the microstrip line on the PCB can be calculated using the following formula (1).

[0135] Formula for calculating the inductance of a PCB microstrip line:

[0136] Where l is the microstrip line length (cm), w is the microstrip line width (cm), and the inductance L is in units of nH. The inductance is independent of the copper thickness and the dielectric constant of the substrate.

[0137] After obtaining the microstrip line length of the microstrip inductor using formula (1), and considering the circuit board layout, the microstrip inductor can be divided into n segments (considering the circuit board mounting dimensions and the adjustable range of each microstrip segment), thus obtaining the sum of the n segments of inductance. (See above.) Figure 4 Schematic diagram of L1 and L2 microstrip line inductors.

[0138] Since each microstrip line segment is connected through vias on the circuit board, the actual inductance of the microstrip line inductor should also take into account the inductance of each via.

[0139] PCB via inductance calculation formula:

[0140] Where h is the via depth (mm), i.e., the circuit board thickness; d is the via diameter (mm). The via inductance is independent of the dielectric constant of the board material.

[0141] The actual inductance of the microstrip inductor can be obtained by combining formula (1) and formula (2). The actual inductance of the microstrip inductor should be greater than 10% of the value calculated by the simulation software. Therefore, the microstrip inductor needs to be adjusted. This can be done by shorting the vias of two adjacent microstrip segments with silver-plated copper wire.

[0142] Step 503: Adjust the number of wafer dielectrics in the first capacitor, second capacitor, and third capacitor according to the target capacitance parameters; and / or, control the on / off state of the capacitance adjustment circuit according to the target capacitance parameters.

[0143] For the RF filter circuit designed above, the capacitance value in the frequency selection network can be adjusted by adjusting the number of wafer dielectrics of the first capacitor, the second capacitor, or the third capacitor, or the capacitance value in the frequency selection network can be adjusted by controlling the on / off state of the capacitor adjustment circuit.

[0144] In this embodiment of the invention, the capacitor element in the frequency selection network is a filled adjustable capacitor. The capacitance value of each capacitor element can be calculated using the following formula (3).

[0145] Capacitance calculation formula:

[0146] Where ε₀ is the vacuum permittivity; ε r denoted as ρ, where ρ is the dielectric constant of the insulating medium; S is the area of ​​the two opposite portions of the electrodes; and d is the thickness of the insulating medium layer.

[0147] Reference Figure 6 The diagram shown is a schematic representation of a filled adjustable capacitor according to an embodiment of the present invention. The insulating medium of the adjustable capacitor is a 0.5mm thick polytetrafluoroethylene (PTFE) sheet, processed to the same size as the capacitor electrodes and stacked. The capacitance value can be adjusted by changing the number of PTFE sheets (i.e., the thickness d), thereby increasing the adjustable precision of the capacitor.

[0148] Reference Figure 7 As shown, for the same as Figure 4 Corresponding circuit board structure diagram. (Refer to...) Figure 8 As shown, for the same as Figure 4 A schematic diagram of the corresponding circuit board structure is shown. The circuit board is equipped with capacitors C1, C2, C2-1, and C3, as well as inductors L1 and L2. The microstrip line lengths of inductors L1 and L2 are obtained using formula (1). After dividing the microstrip line lengths into n segments, the actual inductance in the circuit board can be obtained by combining the via inductance calculation formula (2). The values ​​of adjustable capacitors C1, C2, C2-1, and C3 are obtained according to the capacitance calculation formula (3). By using control signals to select combinations of each group of MOS switching circuits, the frequency selection of various networks is achieved while solving the problem of filter network adjustment accuracy.

[0149] In summary, in this embodiment of the invention, the inductors and capacitors in the frequency selection network of the RF filter circuit can be adjusted in various ways according to the desired target suppression frequency. By employing this method, and combining adjustable microstrip inductors, filled adjustable capacitors, and MOSFET switching characteristics, an RF filter circuit capable of altering different frequency selection networks can be achieved. Through the mutual assistance of calculation and simulation, and after repeated debugging and reasonable layout, the circuit can satisfy harmonic suppression and solve in-band interference while also addressing the defect of inductors in the filter network being susceptible to vibration. The technical solution of this invention achieves the goals of multi-band selection, high integration, good consistency, and high-precision debugging, resulting in significant improvements in overall performance.

[0150] It should be noted that, for the sake of simplicity, the method embodiments are all described as a series of actions. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the described order of actions, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0151] This invention also provides a circuit board structure, including various structures of an RF filter circuit as described above, wherein the RF filter circuit is connected to a heat sink.

[0152] Reference Figure 9 The diagram shown is a side view of a circuit board structure according to an embodiment of the present invention. A MOSFET is placed under the circuit board as a switching device, and the RF filter circuit is fixed to an external heatsink. This solves the heat dissipation problem when a large current flows through the main RF path.

[0153] In one alternative embodiment, the first capacitor, the second capacitor, and the third capacitor can be placed on the same side of the circuit board and grounded over a large area, which helps to better suppress harmonics.

[0154] This invention also provides a semiconductor process apparatus, including a radio frequency (RF) filter device. The RF filter device adopts various structures of an RF filter circuit as described above and can achieve the same technical effect. To avoid repetition, it will not be described again here.

[0155] As the device embodiment is basically similar to the circuit embodiment, the description is relatively simple. For relevant details, please refer to the description of the method embodiment.

[0156] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0157] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, apparatus, or computer program products. Therefore, embodiments of the present invention can take the form of entirely hardware embodiments, entirely software embodiments, or embodiments combining software and hardware aspects. Furthermore, embodiments of the present invention can take the form of computer program products implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0158] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, terminal devices (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing terminal device to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing terminal device, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0159] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing terminal device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0160] These computer program instructions can also be loaded onto a computer or other programmable data processing terminal equipment, causing a series of operational steps to be performed on the computer or other programmable terminal equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable terminal equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0161] Although preferred embodiments of the present invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the embodiments of the present invention.

[0162] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or terminal device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or terminal device. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or terminal device that includes said element.

[0163] The above provides a detailed description of an RF filter circuit, an adjustment method for the RF filter circuit, a circuit board structure, and a wafer cleaning device provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A radio frequency filter circuit, characterized by The application relates to a radio frequency filter circuit. The radio frequency filter circuit comprises a frequency selection network and at least one inductance adjusting circuit, and the inductance adjusting circuit comprises a first MOS tube. The frequency selection network comprises a first inductor, a second inductor, a first capacitor, a second capacitor and a third capacitor. One end of the first capacitor is connected to the input end of the first inductor and the radio frequency input end, and the other end is grounded. The first inductor is connected in series with the second inductor. One end of the second capacitor is connected between the first inductor and the second inductor, and the other end is grounded. One end of the third capacitor is connected to the output end of the second inductor and the radio frequency output end, and the other end is grounded. The first inductor and the second inductor are microstrip inductors, and each microstrip segment is connected based on a via hole.

2. The radio frequency filtering circuit of claim 1, wherein, Each inductance adjusting circuit is connected between two via holes of the first inductor or the second inductor. When the inductance adjusting circuit is turned on, the inductance of the first inductor or the second inductor is reduced. When the inductance adjusting circuit is turned off, the inductance of the first inductor or the second inductor is increased. The inductance adjusting circuit is switched on or off through the first MOS tube. The radio frequency filter circuit further comprises a capacitance adjusting circuit. The frequency selection network further comprises a fourth capacitor. One end of the fourth capacitor is connected to the capacitance adjusting circuit, and the other end is grounded. One end of the capacitance adjusting circuit is connected between the first inductor and the second inductor, and the other end is connected to the fourth capacitor. When the capacitance adjusting circuit is turned on, the fourth capacitor is connected to the frequency selection network. When the capacitance adjusting circuit is turned off, the fourth capacitor is disconnected from the frequency selection network.

3. The radio frequency filter circuit according to claim 1, wherein The inductance adjusting circuit comprises a first resistor and a fifth capacitor. The D pole of the first MOS tube is connected to one via hole of the first inductor or the second inductor, the G pole is connected to the first resistor, and the S pole is connected to the fifth capacitor and a control signal output end. One end of the first resistor is connected to the first MOS tube, and the other end is connected to a control signal input end. One end of the fifth capacitor is connected to the first MOS tube and the control signal output end, and the other end is connected to the other via hole of the first inductor or the second inductor. When the first MOS tube is turned on according to the received control signal, the inductance of the first inductor or the second inductor is reduced. When the first MOS tube is turned off according to the received control signal, the inductance of the first inductor or the second inductor is increased.

4. The radio frequency filter circuit according to claim 1, wherein The number of inductance adjusting circuits connected to the first inductor is the same as the number of inductance adjusting circuits connected to the second inductor. When a first number of inductance adjusting circuits connected to the first inductor are turned on, a first number of inductance adjusting circuits connected to the second inductor are turned on. When a second number of inductance adjusting circuits connected to the first inductor are turned off, a second number of inductance adjusting circuits connected to the second inductor are turned off.

5. The radio frequency filter circuit according to claim 2, wherein The capacitance adjusting circuit comprises a second MOS tube and a second resistor; The D pole of the second MOS tube is connected between the first inductor and the second inductor, the G pole is connected with the second resistor, and the S pole is connected with the fourth capacitor and a control signal output end; One end of the second resistor is connected with the second MOS tube, and the other end is connected with a control signal input end; When the second MOS tube is turned on according to the received control signal, the fourth capacitor is connected to the frequency selection network; when the second MOS tube is turned off according to the received control signal, the fourth capacitor is disconnected from the frequency selection network.

6. The radio frequency filter circuit of any of claims 1-5, wherein, The first capacitor, the second capacitor, the third capacitor and the fourth capacitor are all adjustable capacitors, and the fifth capacitor is a fixed capacitor; the medium of the adjustable capacitor is polytetrafluoroethylene.

7. The radio frequency filter circuit of any of claims 1-5, wherein, The arrangement directions of the microstrip line segments of the first inductor and the second inductor are different.

8. A method of tuning a radio frequency filter circuit, characterized by, The method is applied to the radio frequency filter circuit of any one of claims 1-5, and the method comprises: determining a target suppression frequency, and determining target inductance parameters and target capacitance parameters required by the radio frequency filter circuit according to the target suppression frequency; adjusting the short-circuit mode of the microstrip line segments adjacent to each other in the middle of the first inductor or the second inductor according to the target inductance parameters; and / or adjusting the on-off combination mode of each inductance adjusting circuit according to the target inductance parameters; adjusting the number of wafer media in the first capacitor, the second capacitor and the third capacitor according to the target capacitance parameters; and / or controlling the on-off of the capacitance adjusting circuit according to the target capacitance parameters.

9. A circuit board structure, characterized by The radio frequency filter circuit comprises the radio frequency filter circuit of any one of claims 1-5, and the radio frequency filter circuit is connected with a heat sink.

10. A semiconductor process apparatus comprising a radio frequency filter device, characterized in that, The radio frequency filter device adopts the radio frequency filter circuit of any one of claims 1-5.

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