Filter, filtering switching method and device and electronic equipment

Abstract

The invention discloses a filter, a filtering switching method and device and electronic equipment. The filter comprises a main driving module, a main tuning module, a secondary tuning module and a secondary driving module, and the main driving module is connected with a signal input end and used for controlling the working state of the main tuning module according to a first control signal; the main tuning module is connected with the main driving module and the signal output end and is used for switching on or switching off a transmission signal; the secondary tuning module is connected with the signal input end and the signal output end and is used for conducting an out-of-band signal of the transmission signal output by the main tuning module; and the secondary driving module is connected with the secondary tuning module and is used for connecting or disconnecting the secondary tuning module and the grounding end according to the second control signal. According to the invention, the technical problem of low flexibility of the filter caused by the fact that the filter cannot switch low-pass and high-pass filtering characteristics in the prior art is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of communication systems, and in particular, to a filter, a filtering switching method, a device, and an electronic device. Background Art

[0002] In wireless devices, filters are used to solve signal interference. Conventional filters have fixed filtering characteristics and can only be used as high-pass filters or low-pass filters, making it difficult to reconstruct and switch between low-pass and high-pass filtering characteristics. As a result, the flexibility of the filter is low, and its anti-interference ability is also limited.

[0003] In view of the above problems, no effective solution has been proposed yet. Summary of the Invention

[0004] Embodiments of the present invention provide a filter, a filtering switching method, a device, and an electronic device to at least solve the technical problem in the related art that the flexibility of the filter is low because it cannot switch between low-pass and high-pass filtering characteristics.

[0005] According to one aspect of the embodiments of the present invention, a filter is provided, which includes a main driving module, a main tuning module, a secondary tuning module, and a secondary driving module. Among them, the main driving module is connected to the signal input end and is used to control the working state of the main tuning module according to a first control signal; the main tuning module is connected to the main driving module and the signal output end and is used to conduct or disconnect the transmission signal. Among them, when the main driving module controls the main tuning module to be in the conducting state, the filter is in the low-pass filtering state, and when the main driving module controls the main tuning module to be in the disconnecting state, the filter is in the high-pass filtering state; the secondary tuning module is connected to the signal input end and the signal output end and is used to conduct the out-of-band signal of the transmission signal output by the main tuning module; the secondary driving module is connected to the secondary tuning module and is used to conduct or disconnect the connection between the secondary tuning module and the grounding end according to a second control signal.

[0006] Optionally, the secondary tuning module includes a first stub, where the first end of the first stub is connected to the signal input end, and the end of the first stub is grounded after being connected to the secondary driving module.

[0007] Optionally, the secondary driving module includes a secondary driving unit and a first stub diode. Among them, the secondary driving unit is used to control the working state of the first stub diode. When the secondary driving unit controls the first stub diode to be in the disconnecting state, the first stub allows high-frequency signals to pass through, and when the secondary driving unit controls the first stub diode to be in the conducting state, the first stub allows low-frequency signals to pass through.

[0008] Optionally, the main tuning module includes a main diode, where the first end of the main diode is connected to the main driving module, and the second end of the main diode is connected to the signal output end.

[0009] Optionally, the first stub is a microstrip stub, and the first stub includes a first component and a second component, wherein the width of the first component is smaller than the width of the second component.

[0010] Optionally, the main driving module, the main tuning module, the secondary tuning module and the secondary driving module form a first-stage filtering, and one or more other-stage filterings including the main driving module, the main tuning module, the secondary tuning module and the secondary driving module are cascaded after the first-stage filtering.

[0011] Optionally, it further includes a control module, wherein the first control signal is a bias voltage, and the control module is connected to the main driving module for applying the bias voltage to the main driving module to control the working state of the main driving module.

[0012] According to another aspect of the embodiments of the present invention, there is also provided a filtering switching method, which is applied to any one of the above filters, and includes: receiving a filtering switching request; based on the filtering switching request, adjusting the working state of the main tuning module in the filter through the main driving module and simultaneously adjusting the suppression state of the secondary tuning module through the secondary driving module to implement the switching of the filtering state of the filter.

[0013] According to another aspect of the embodiments of the present invention, there is also provided a filtering switching device for implementing any one of the above filtering switching methods.

[0014] According to still another aspect of the present invention, there is provided an electronic device including any one of the above filters and / or the above filtering switching device.

[0015] In the embodiments of the present invention, a filter is adopted, which includes a main driving module, a main tuning module, a secondary tuning module and a secondary driving module. The main driving module is connected to the signal input end for controlling the working state of the main tuning module according to the first control signal; the main tuning module is connected to the main driving module and the signal output end for conducting or disconnecting the transmitted signal. When the main driving module controls the main tuning module to be in the conducting state, the filter is in the low-pass filtering state, and when the main driving module controls the main tuning module to be in the disconnected state, the filter is in the high-pass filtering state; the secondary tuning module is connected to the signal input end and the signal output end for conducting the out-of-band signal of the transmitted signal output by the main tuning module; the secondary driving module is connected to the secondary tuning module for conducting or disconnecting the connection between the secondary tuning module and the grounding end according to the second control signal, achieving the purpose of flexibly switching between the low-pass filtering state and the high-pass filtering state, thereby realizing the technical effect of improving the flexibility and anti-interference ability of the filter, and further solving the technical problem that the filter in the related art has low flexibility because it cannot switch between the low-pass and high-pass filtering characteristics. Description of the Drawings

[0016] The accompanying drawings described herein are used to provide a further understanding of the present invention and form a part of this application. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and shall not constitute an improper limitation to the present invention. In the drawings:

[0017] Figure 1 is a schematic structural diagram of a filter provided according to an embodiment of the present invention;

[0018] Figure 2 is a schematic structural diagram of a filter provided according to an alternative embodiment of the present invention;

[0019] Figure 3 is an equivalent structural diagram of a filter provided according to an alternative embodiment of the present invention under low-pass characteristics;

[0020] Figure 4 is an equivalent circuit diagram of a filter provided according to an alternative embodiment of the present invention under low-pass characteristics;

[0021] Figure 5 is an equivalent structural diagram of a filter provided according to an alternative embodiment of the present invention under high-pass characteristics;

[0022] Figure 6 is an equivalent circuit diagram of a filter provided according to an alternative embodiment of the present invention under high-pass characteristics;

[0023] Figure 7 is an equivalent structural diagram of a filter provided according to an alternative embodiment of the present invention;

[0024] Figure 8 is a schematic diagram of the first stub in a filter provided according to an alternative embodiment of the present invention;

[0025] Figure 9 is a schematic diagram of the first cascade of the first-stage filtering and the second-stage filtering in a filter provided according to an alternative embodiment of the present invention;

[0026] Figure 10 is a schematic diagram of the second cascade of the first-stage filtering and the second-stage filtering in a filter provided according to an alternative embodiment of the present invention;

[0027] Figure 11 is a schematic diagram of the third cascade of the first-stage filtering and the second-stage filtering in a filter provided according to an alternative embodiment of the present invention;

[0028] Figure 12 is a schematic diagram of the fourth cascade of the first-stage filtering and the second-stage filtering in a filter provided according to an alternative embodiment of the present invention;

[0029] Figure 13 is a curve graph of the filtering effect of a filter provided according to an alternative embodiment of the present invention under low-pass characteristics;

[0030] Figure 14 is a filtering effect curve graph of the filter provided according to an alternative embodiment of the present invention under high-pass characteristics;

[0031] Figure 15 is a schematic flowchart of a filtering switching method provided according to an embodiment of the present invention. Detailed implementation manners

[0032] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the description and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "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 does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0034] First, some nouns or terms that appear during the description of the embodiments of the present application are applicable to the following explanations:

[0035] The low-pass filtering state means that the filter allows signals below a specific frequency (referred to as the cut-off frequency) to pass through, while attenuating or blocking signals above that frequency. In a circuit, a low-pass filter is usually used to remove high-frequency noise, protect signals from the influence of high-frequency interference, or in audio processing to eliminate unwanted high-frequency components, such as whistles or high-frequency noise.

[0036] In the high-pass filtering state, the filter allows signals above a certain cut-off frequency to pass through while attenuating signals below this cut-off frequency. On the frequency characteristic curve, the high-pass filter provides attenuation close to 0 dB (i.e., the signal is basically unaffected) in the frequency region above the cut-off frequency, while providing significant attenuation in the frequency region below the cut-off frequency. Such filters are commonly used in audio processing, signal denoising, removal of DC components, and other applications that require elimination of low-frequency signals. In the field of wireless communication, high-pass filters can be used to eliminate low-frequency interference in signals and ensure the pure transmission of high-frequency signals.

[0037] Out-of-band signals refer to signals whose frequencies fall outside the passband of the filter. A filter is an electronic device used for signal processing that can pass, attenuate, or completely block certain frequency components in a signal. The passband of a filter is the frequency range in which signals can pass through with relatively small attenuation, while out-of-band refers to the frequency range that the filter is designed to suppress or block. For example, when the filter is in the high-pass characteristic state and allows high-frequency signals to pass through, then low-frequency signals are out-of-band signals. When the filter is in the low-pass characteristic state and allows low-frequency signals to pass through, then high-frequency signals are out-of-band signals.

[0038] In practical applications, filters often combine with other devices or components to meet specific performance requirements or build more complex systems. For example, in a wireless communication system, filters can combine with components such as antennas, amplifiers, mixers, and oscillators to jointly form a radio frequency front-end module for signal reception, transmission, and processing. In mobile communication devices or WIFI routers, filters are usually integrated into the radio frequency circuit for frequency band selection, signal separation, or interference suppression. In addition, filters can also combine with digital signal processors (DSPs), analog-to-digital converters (ADCs), or digital-to-analog converters (DACs) for signal preprocessing or postprocessing to improve signal quality and system performance. Currently, the filter characteristics are fixed, that is, it can only be used as a high-pass filter or a low-pass filter, and it is difficult to switch between low-pass and high-pass characteristics. This results in relatively low flexibility of the filter, which in turn affects the anti-interference ability of the devices combined with the filter.

[0039] To address the above technical problems, an embodiment of the present invention proposes a filter. Figure 1 It is a schematic structural diagram of the filter provided according to an embodiment of the present invention, as Figure 1As shown in the figure, the filter includes a main driving module, a main tuning module, a secondary tuning module, and a secondary driving module. Among them, the main driving module is connected to the signal input terminal and is used to control the working state of the main tuning module according to the first control signal; the main tuning module is connected to the main driving module and the signal output terminal and is used to conduct or disconnect the transmitted signal. Among them, when the main driving module controls the main tuning module to be in the conducting state, the filter is in the low-pass filtering state, and when the main driving module controls the main tuning module to be in the disconnected state, the filter is in the high-pass filtering state; the secondary tuning module is connected to the signal input terminal and the signal output terminal and is used to conduct the out-of-band signal of the transmitted signal output by the main tuning module; the secondary driving module is connected to the secondary tuning module and is used to conduct or disconnect the connection between the secondary tuning module and the ground terminal according to the second control signal.

[0040] As Figure 1 shown, among which, the main driving module and the main tuning module can be connected through a main transmission line, and the main transmission line is the main path for the transmitted signal to pass through. The main purpose of the filter is to selectively pass signals within a certain frequency range from the transmitted signal. When the filter is in the low-pass filtering state, low-frequency signals are allowed to pass on the main transmission line, and when the filter is in the high-pass filtering state, high-frequency signals are allowed to pass on the main transmission line. In a microstrip filter, the main transmission line is usually a microstrip line printed on a dielectric substrate and will have a certain impedance to match other components in the filter. Optionally, the impedance of the main transmission line is set to 50 ohms. In order to achieve the best signal transmission and filtering effect, impedance matching is a key factor in the setting of the main transmission line, which can ensure the minimum energy loss of the signal during transmission. Therefore, the impedance of the main transmission line can be set to 50 ohms to ensure compatibility with most radio frequency devices. The secondary driving module is located between the secondary tuning module and the ground terminal and is used to control the conduction state between the secondary tuning module and the ground terminal according to the second control signal.

[0041] The function of the main tuning module is to allow the transmitted signal to pass through, while the function of the secondary tuning module is to allow the out-of-band signal of the transmitted signal to pass through. When the filter is a low-pass filter, at this time the filter needs to filter out high-frequency signals and allow low-frequency signals to pass through. At this time, the high-frequency signal is the out-of-band signal. When the filter is a high-pass filter, at this time the filter needs to filter out low-frequency signals and allow high-frequency signals to pass through. At this time, the low-frequency signal is the out-of-band signal.

[0042] As an optional embodiment, the main tuning module includes a main diode, where the first end of the main diode is connected to the main driving module, and the second end of the main diode is connected to the signal output terminal.

[0043] Figure 2 is a schematic structural diagram of a filter provided according to an optional embodiment of the present invention. As Figure 2As shown, it includes a main tuning module 1, a secondary tuning module 2, a main driving module 3, and a secondary driving module 4. Port1 is the signal input terminal, and Port2 is the signal output terminal. Among them, the main tuning module 1 includes a main diode. The first end of the main diode is connected to the main driving module 3, and the other end is connected to the Port2 signal output terminal. Among them, the main diode in the main tuning module 1 can be a PIN diode, and its function is to form an equivalent inductor or equivalent capacitor under different working states to control the transmission signal to pass through. Among them, the working state of the main diode is controlled by the main driving module 3. The secondary tuning module 2 is used to conduct the out-of-band signals in the transmission signal, thereby suppressing the out-of-band signals from being conducted through the main transmission line. The secondary driving module 4 is used to connect the secondary tuning module 2 to the ground terminal in a conducting or disconnecting manner according to the second control signal. The main driving module 3 may include a bias resistor R 1 , which is used to limit the current during voltage conversion to prevent the main diode from being damaged. It also includes a DC-blocking capacitor C 1 , which is used to block the direct connection between the DC power supply and the RF signal and avoid the DC voltage affecting the transmission of the RF signal. The main driving module 3 can receive an externally applied bias voltage V 1 (i.e., the first control signal). When the bias voltage V 1 is a positive voltage, the main diode is in a conducting state. When the bias voltage V 1 is a negative voltage, the main diode is in a disconnected state.

[0044] Figure 3 is the equivalent structure diagram of the filter provided by an optional embodiment of the present invention under the low-pass characteristic. As Figure 3 shown, in the case of the low-pass filtering state, at this time, the main diode in the main tuning module is conducting, the inductor is equivalent, the secondary tuning module is equivalent to a capacitor, and the low-frequency signal can be transmitted through the main tuning module. Figure 4 is the equivalent circuit diagram of the filter provided by an optional embodiment of the present invention under the low-pass characteristic. As Figure 4 shown, when the main driving module controls the main diode to be in the forward bias state (i.e., conducting or short-circuiting), its impedance becomes very low and can be approximated as a small resistor. At this time, the main tuning module is equivalent to an inductor, that is, Figure 4 the L in 1 , L 2 , among which, L 1 is the equivalent inductor formed when the main diode is in the conducting state, forming a low-impedance path on the transmission line where the main tuning module is located and a high impedance in the secondary tuning module. This is a path for low-frequency signals, while for high-frequency signals, due to the higher frequency, the inductive reactance will increase significantly when passing through the inductor, thereby forming a greater obstacle to the signal. High-frequency signals will encounter higher impedance in the inductor, resulting in signal attenuation and phase delay. Therefore, the filter at this time exhibits low-pass characteristics.

[0045] On the contrary, Figure 5 is the equivalent structural diagram of the filter provided by an alternative embodiment of the present invention under high-pass characteristics, as Figure 5 shown. In the case of the high-pass filtering state, at this time, the main diode in the main tuning module is disconnected, capacitively coupled, the capacitance of the main tuning module is equivalent, the inductance of the secondary tuning module is equivalent, and high-frequency signals can be transmitted from the main tuning module. Figure 6 is the equivalent circuit diagram of the filter provided by an alternative embodiment of the present invention under high-pass characteristics, as Figure 6 shown. When the main drive module controls the main diode to be in the reverse bias state (i.e., disconnected or open circuit), its impedance is very high and can be approximated as infinite. At this time, the equivalent capacitance of the main tuning module, that is, Figure 6 the C in f and L in 2 , where C f is the equivalent capacitance formed when the main diode is in the disconnected state. For low-frequency signals, the main tuning module is equivalent to a high-impedance path, which blocks low-frequency signals. However, when high-frequency signals pass through the capacitor, due to the increase in frequency, the capacitive reactance decreases, and the blocking effect of the capacitor on the signal is reduced. Therefore, high-frequency signals can pass through the capacitor relatively easily. So for high-frequency signals, the main tuning module behaves as a low-impedance path. Therefore, the filter at this time exhibits high-pass characteristics.

[0046] The above filter realizes the switchable high-pass and low-pass filtering characteristics, and the filter has a simple structure, low cost, a simple diode control circuit, and a low overall design cost. It not only realizes the high-pass and low-pass switching to improve the flexibility of the filter, but also can reduce the cost.

[0047] It should be noted that Figure 1 the above-described embodiments are merely illustrative. In actual applications, the above structure can be adaptively modified. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made to the structure, and these improvements and refinements should also be regarded as the protection scope of the present invention.

[0048] The filter can be a microstrip filter. A microstrip filter is a filter designed using microstrip line technology and is widely used in radio frequency (RF) and microwave communication systems. A microstrip line is a planar transmission line structure composed of a wideband metal strip line and a ground plane, separated by a layer of dielectric material in between. This structure can be realized in a relatively small physical space, so microstrip filters usually have the advantages of small size, light weight, easy integration, and low cost. In modern communication devices, microstrip filters are used for signal processing, such as signal isolation, frequency selection, and interference suppression, to ensure clear signal transmission. Due to its planar structure, microstrip filters are particularly suitable for integration on printed circuit boards (PCBs) and together with other RF components (such as amplifiers, mixers) form complex RF systems.

[0049] As an alternative embodiment, the sub-tuning module includes a first stub. The head end of the first stub is connected to the signal input terminal, and the end of the first stub is grounded after being connected to the sub-driving module.

[0050] As an alternative embodiment, the sub-driving module includes a sub-driving unit and a first stub diode. The sub-driving unit is used to control the working state of the first stub diode. When the sub-driving unit controls the first stub diode to be in the off state, the first stub allows high-frequency signals to pass through. When the sub-driving unit controls the first stub diode to be in the on state, the first stub allows low-frequency signals to pass through. The sub-driving unit is used to control the working state of the first stub diode according to a second control signal. When the sub-driving unit controls the first stub diode to be in the off state, the first stub allows high-frequency signals to pass through. When the sub-driving unit controls the first stub diode to be in the on state, the first stub allows low-frequency signals to pass through.

[0051] As Figure 2 shown, the sub-driving unit is Figure 2 shown by the dashed box 4 in 2 and is used to control the first stub diode connected thereto according to the second control signal, for example, to control the first direct diode connected thereto to conduct or disconnect according to the bias voltage V Figure 7 is an equivalent structure diagram of a filter provided according to an alternative embodiment of the present invention. As Figure 7 shown, a first stub is within the dashed box. The head end of the first stub can be connected to the signal input terminal (i.e., Figure 7 Port1 in ). The end of the first stub can be grounded through the sub-driving module and the first stub diode. The sub-driving module can control the working state of the first stub diode, and the specific control method can be the same as the control method of the main driving module for controlling the main diode.

[0052] When the first stub diode is in the conducting state, the first stub is directly grounded at this time. The equivalent inductance of the first stub is such that in this case, the equivalent inductance forms a path for low-frequency signals. Therefore, when the stub diode is in the conducting state and the main diode is in the off state, the filter is in a high-pass filtering state. The equivalent capacitance of the main tuning module is a low-impedance path for high-frequency signals, and high-frequency signals pass through the main tuning module. The equivalent inductance of the first stub is a low-impedance path for low-frequency signals, and low-frequency signals pass through the first stub and lead to the ground, which is equivalent to suppressing the low-frequency signals from reaching the signal transmission outlet. When the stub diode is in the off state, the first stub is equivalent to a capacitance at this time. In this case, the equivalent capacitance forms a path for high-frequency signals. Therefore, when the stub diode is in the off state and the main diode is in the conducting state, the filter is in a low-pass filtering state. The equivalent inductance of the main tuning module is a low-impedance path for low-frequency signals, and low-frequency signals pass through the main tuning module. The equivalent capacitance of the first stub is a low-impedance path for high-frequency signals, and high-frequency signals pass through the first stub and lead to the ground, which is equivalent to suppressing the high-frequency signals from reaching the signal transmission outlet.

[0053] A first stub diode is arranged at the end of the first stub to control the state of the suppression circuit, which can more effectively suppress the conduction of out-of-band signals, thereby improving the filtering performance of the filter. Among them, both the first stub diode and the main diode can be PIN diodes. A PIN diode is a special semiconductor diode, where PIN stands for P (Positive, anode), I (Intrinsic, intrinsic), and N (Negative, cathode) respectively. Different from ordinary diodes, a PIN diode has an intrinsic (undoped) region between the P-type and N-type semiconductors. This region can act as an insulator when the diode is reverse-biased, and will conduct electricity and present a low impedance when forward-biased. Therefore, the characteristics of PIN diodes make them widely used in the radio frequency (RF) and microwave fields, especially in tunable and reconfigurable circuits. When a PIN diode is forward-biased, its I region exhibits a relatively low resistance and can be approximately regarded as a wire, and the diode is in the conducting state at this time; when reverse-biased, the I region exhibits a high capacitance and can be approximately regarded as a capacitor. Therefore, PIN diodes are used to achieve the switching of filter characteristics (low-pass or high-pass). By controlling the forward and reverse biasing of the PIN diode, the structure of the filter can be changed, thereby changing its filtering characteristics.

[0054] The first stub is a microstrip stub, and the first stub includes a first component and a second component, and the width of the first component is smaller than the width of the second component.

[0055] Figure 8 It is a schematic diagram of the first stub in the filter provided according to an optional embodiment of the present invention, whereFigure 8 The first sub-section in Figure 7 the first sub-section within the dashed box in Figure 8 The dashed box 1 in Figure 4 and Figure 6 the L in 3 at. The part with impedance greater than the transmission line impedance in the main tuning module (usually 50 ohms), the sub-section will exhibit a higher impedance characteristic, which is equivalent to a capacitor in circuit theory. This is because the high-impedance microstrip line shows a smaller current and a larger voltage in current distribution, which is similar to the characteristics of a capacitor. In filter design, through this capacitance effect, a resonance point can be formed at a specific frequency, thereby affecting the passband and stopband characteristics of the filter. This makes the sub-section equivalent to a capacitor when the sub-section diode is disconnected. When the diode in the main tuning module is turned on, the entire filter structure behaves as a low-pass filter. Conversely, when the sub-section diode of the sub-section is turned on and the main diode in the main tuning module is disconnected, the sub-section is equivalent to an inductor, and the main tuning module is equivalent to a capacitor, and the entire filter structure behaves as a high-pass filter, and low-frequency signals will be blocked, while high-frequency signals can pass through the main tuning module. Therefore, by controlling the on and off states of the main diode and the sub-section diode and combining the sub-section impedance design, the switching between low-pass and high-pass filter characteristics can be flexibly achieved.

[0056] As an optional embodiment, the negative electrode of the main diode is grounded through a second sub-section.

[0057] Since the main driving module controls the working state of the main diode by receiving the bias voltage of the control module, there will be a DC current. Therefore, the negative electrode of the main diode needs to be grounded through a second sub-section. The second sub-section can be designed with a structure similar to the first sub-section, consisting of a part with impedance less than the transmission line impedance in the main driving module and a part with impedance greater than the transmission line impedance in the main driving module. There is no diode directly grounded between the second sub-section and the ground. The current generated when the main driving module applies voltage to the main diode can be led to the ground through the second sub-section.

[0058] As an alternative embodiment, the main driving module, the main tuning module, the secondary tuning module, and the secondary driving module form a first-stage filtering, and one or more other stages of filtering including the main driving module, the main tuning module, the secondary tuning module, and the secondary driving module are cascaded after the first-stage filtering.

[0059] The driving module, the main tuning module, the secondary tuning module, and the secondary driving module form a first-stage filtering, that is, a resonator, that is Figure 1 The figure shows the filter result composed of a single resonator. However, in the filter, one or more other stages of filtering that also include the main transmission line and the corresponding suppression circuit can be cascaded after the first-stage filter. Compared with the first-stage filtering, the cascaded multi-stage filtering has a better filtering effect. Figure 9 FIG. is a first cascading schematic diagram of the first-stage filtering and the second-stage filtering in the filter provided according to an alternative embodiment of the present invention, as Figure 9 shown is the cascading schematic diagram of the first-stage filtering and the second-stage filtering. In the filter, the cascaded two-stage filtering has a better suppression ability compared with the first-stage filtering. Because when a higher suppression ratio needs to be achieved outside the filter band, the use of multiple resonators can significantly improve the suppression ability of the filter, ensuring that signals outside a specific frequency band are effectively attenuated. Moreover, by adjusting the parameters of different resonators, complex frequency responses including band-pass, band-stop, notch, comb filtering, etc. can be achieved. This is very important in applications that require specific signal processing, such as in multi-band communication systems where signals at specific frequency points need to be filtered out. At the same time, the cascaded multi-stage filtering can also improve the stability of the filter.

[0060] After the first-stage filtering, a second-stage filtering including the driving module, the main tuning module, the secondary tuning module, and the secondary driving module is cascaded, and the signal output end corresponding to the first-stage filtering can be connected to the signal input end corresponding to the second-stage filtering.

[0061] Optionally, as Figure 9 shown, the connection method of cascading the second-stage filtering after the first-stage filtering is to connect the signal output end corresponding to the first-stage filtering to the signal input end corresponding to the second-stage filtering. After the transmitted signal is filtered by the first-stage filtering, the passed signal will enter the second-stage filtering for further filtering, improving the filtering effect and better suppressing out-of-band signals.

[0062] The filter structure composed of the cascaded first-stage filtering and the second-stage filtering can be as Figure 9As shown, among them, the branches from left to right are the first branch, the second branch, the third branch, and the fourth branch. The first branch and the second branch form the sub-tuning module of the first-stage filtering, and the third branch and the fourth branch form the sub-tuning module of the second-stage filtering. Among them, the ends of the first branch, the third branch, and the fourth branch are all connected to the branch diode and grounded. The third branch and the fourth branch can be set to the same connection method as the first branch, that is, grounded through the sub-driving module, and the second branch is directly grounded. The directions of the main diodes corresponding to the first-stage filtering and the second-stage filtering are opposite, that is, as Figure 9 shown. Among them, because the current direction of the diode is from the positive pole to the negative pole, by setting the directions of the two main diodes to be opposite, only one branch needs to be grounded at the connection of the first-stage filtering and the second-stage filtering, that is, Figure 9 the second branch in

[0063] is grounded at the branch. Similarly, the third branch can also be set to a directly grounded structure, or both the second branch and the third branch are designed to be directly grounded structures. The ends of the branches are designed to be connected to the diodes, so that the branches participate in the filtering adjustment process, improving the suppression effect of out-of-band signals. Figure 9 Specifically, as

[0064] Figure 10 shown in the second cascading schematic diagram of the first-stage filtering and the second-stage filtering in the filter provided by the optional embodiment of the present invention. As Figure 10 shown, the second-stage filtering is the filtering structure on the right, and the third branch is the left branch in the second-stage filtering; the fourth branch, that is, the right branch in the second-stage filtering, can be set to be directly grounded, or can also be set to be connected to the branch diode, that is, Figure 9The filter structure shown in [description]. The more stubs connected to the stub diode, the more stubs for filtering regulation are added, and the better the suppression effect of the out-of-band signal will be.

[0065] Figure 11 is the third cascade schematic diagram of the first-stage filtering and the second-stage filtering in the filter provided according to an alternative embodiment of the present invention, as Figure 11 shown, the third stub is connected to the ground, and the fourth stub is connected to the ground through the sub-driving module and the fourth stub diode. The control method of the sub-driving module for the fourth stub diode can be the same as the control method of the sub-driving module for the first stub diode in the first-stage cascade, that is, the diode conducts when a positive voltage is applied, and the diode disconnects when a negative voltage is applied.

[0066] The negative poles of the main diodes in the main tuning module corresponding to the first-stage filtering and the negative poles of the main diodes in the main tuning module corresponding to the second-stage filtering are connected and grounded.

[0067] Figure 12 is the fourth cascade schematic diagram of the first-stage filtering and the second-stage filtering in the filter provided according to an alternative embodiment of the present invention, as Figure 12 shown, wherein, the orientations of the main diodes corresponding to the first-stage filtering and the second-stage filtering are the same, so the second stub and the fourth stub are both set to be directly grounded. When the main driving module in the first-stage filtering receives the bias voltage applied by the control circuit to control the corresponding main diode, the generated current will flow from the second stub to the ground. When the main driving module in the second-stage filtering receives the bias voltage applied by the control circuit to control the corresponding main diode, the generated current will flow from the fourth stub to the ground.

[0068] Among them, the direction of the main diode can be set arbitrarily, as long as the corresponding stub is set to be directly grounded. Similarly, the remaining stubs can be selected to be directly grounded or connected to the stub diode at the end and then grounded, and can be combined arbitrarily. However, the more stubs connected to the stub diode at the end, the more stubs added to the filtering regulation, and the better the corresponding out-of-band suppression effect will be.

[0069] Optionally, it further includes a control module. Among them, the first control signal is a bias voltage, and the control module is connected to the main driving module and is used to apply a bias voltage to the main driving module to control the working state of the main driving module. For example, when the voltage applied by the control module is a positive voltage, that is, when the first control signal sent is a positive voltage, the control module can control the main driving module to control the main tuning module to be in a conducting state; when the applied voltage is a negative voltage, that is, when the first control signal sent is a negative voltage, the control module can control the main driving module to control the main tuning module to be in a disconnected state.

[0070] Similarly, the control module can also be connected to the secondary drive module to issue a second control signal to control the control state of the secondary drive module. The control module corresponding to the main drive module and the control module corresponding to the secondary drive module can be different control modules or the same control module. In the case of the same control module, this control module can issue the first control signal and the second control signal simultaneously.

[0071] For example, by adjusting the output V of the control module corresponding to the main drive module 1 、V 3 to apply a forward voltage to the main diodes in their respective corresponding main drive modules. At this time, the two main diodes are in the conducting state. By adjusting the output V of the control module corresponding to the secondary drive module 2 、V 4 、V 5 to apply a negative voltage to their respective corresponding stub diodes. At this time, the stub diodes are all in the off state. At this time, a low-impedance path is formed on the main tuning module, and the low-frequency signals in the transmitted signal can pass through, while high-frequency signals will be reflected. At this time, it is in the low-pass filtering state. Figure 13 is the filtering effect curve diagram of the filter provided by an optional embodiment of the present invention under the low-pass characteristic, as Figure 13 shown, the cut-off frequency of the low-pass filter is 5 GHz, Figure 13 which reflects the variation relationship between the S parameter and the frequency. Among them, the S parameter is a set of parameters used in microwave and radio frequency engineering to describe the performance of networks (such as filters, amplifiers, mixers, etc.). The S parameter can represent the reflection and transmission characteristics of the network. Especially in a multi-port network, it can clearly show the input and output characteristics of each port. Figure 13 The S(1, 1) in Figure 13 , that is, the parameter corresponding to curve 1 in Figure 13 , is the return loss, which means that a part of the incident power is reflected back to the signal source. The larger the return loss, the smaller the reflected power and the higher the signal transmission efficiency. S(2, 1), that is, the parameter corresponding to curve 2 in

[0072] , is the insertion loss, which refers to the attenuation of the original signal in the circuit due to the introduction of the filter, usually expressed in decibels (dB). The larger the insertion loss, the greater the attenuation degree.

[0073] By adjusting V 1 、V 3A negative voltage is applied to the respective main diodes. At this time, the two main diodes are in the off state. By adjusting V 2 、V 4 、V 5 A positive voltage is applied to the respective stub diodes. At this time, the stub diodes are all in the on state. At this time, the high-frequency signals in the transmitted signal can pass through the main tuning module, while the low-frequency signals cannot pass through. At this time, it is in the high-pass filtering state. Figure 14 is the filtering effect curve of the filter provided by an alternative embodiment of the present invention under the high-pass characteristic, as Figure 14 shown, the cut-off frequency of the high-pass filter is 2.2 GHz, Figure 14 reflects the variation relationship between the S parameter and the frequency, Figure 14 S(1, 1) in Figure 14 i.e., the parameter corresponding to curve 1 in Figure 14 is the return loss, which represents that a part of the incident power is reflected back to the signal source. The greater the return loss, the smaller the reflected power and the higher the signal transmission efficiency. S(2, 1), i.e., the parameter corresponding to curve 2 in

[0074] Therefore, by controlling the working state of the corresponding diodes through the control circuit, the characteristic switching between low-pass filtering and high-pass filtering can be realized, which can meet the use in different situations. In the application of communication equipment, the anti-interference ability of the communication equipment can be improved.

[0075] Figure 9 In 1 、V 3 , that is, the voltage applied to the main drive module corresponding to the main diode, can be connected to the same control voltage, that is, the same control module, because the applied voltages are all the same, both positive voltage and negative voltage. Similarly, V 2 、V 4 、V 5 , that is, the voltages applied to the secondary drive modules corresponding to the stub diodes respectively can also be connected to the same control voltage, that is, the same control module, so that the structure can be simple and the cost can be reduced.

[0076] Through such a configuration, the flexible switching of the filter characteristics can be realized, so as to provide the required filtering function in different application scenarios. This design is particularly useful in communication systems because it can improve the flexibility and anti-interference ability of the equipment.

[0077] The main tuning module, the main driving module, the secondary tuning module, and the secondary driving module can be integrated on a dielectric substrate, where the dielectric substrate is a polytetrafluoroethylene dielectric substrate. Among them, the transmission line corresponding to the main tuning module can be printed on the TOP layer of the dielectric substrate, with a length of about one wavelength and a width of 50-ohm line width. The secondary tuning module is printed below. The secondary tuning module can include multiple stubs, and the length of each stub can be designed to be about one-quarter wavelength. The one-quarter wavelength is based on the characteristics of electromagnetic waves on the transmission line. When an electromagnetic wave propagates on a transmission line, if the length of the transmission line is one-quarter of the wavelength of the electromagnetic wave, then this line has special reactance characteristics. Specifically, if the length of an open (not connected to any load or short-circuited) transmission line is one-quarter wavelength, when a signal is input from one end, it will be reflected back after reaching the other end of the line. This reflection will cause a phase change, resulting in the other end of the line appearing to be connected to a reactance element (usually an inductor). This is because the reflected signal has a 180-degree phase difference from the input signal, and the one-quarter wavelength line exactly provides such a phase change, making the reflected signal and the input signal form an inductive phase relationship. Conversely, if the end of the one-quarter wavelength line is short-circuited, when a signal is input from one end and reaches the end, due to the short circuit, the signal will be reflected back, but this reflection will not cause a voltage at the end, only a 180-degree phase flip of the current. In this way, this line appears to be connected to a capacitor at the input end because the reflected signal and the input signal form a capacitive phase relationship. Therefore, by designing the length of the stub line of the filter to be one-quarter wavelength and combining the switching states (conducting or open) of the main diode and the stub diode, capacitive or inductive control of electromagnetic waves can be achieved, and thus the characteristics of the filter can be adjusted, such as converting from low-pass to high-pass, or vice versa. This design utilizes the characteristics of the transmission line and can change the frequency response characteristics of the filter by controlling the state of the diode without changing the physical structure of the filter, thereby improving the flexibility and adaptability of the filter.

[0078] When designing a microstrip filter, the choice of the dielectric substrate material mainly depends on factors such as dielectric constant, loss factor, thermal stability, strength, cost, and processing characteristics. Common dielectric substrate materials can include PTFE (polytetrafluoroethylene): It has a very low dielectric constant and loss factor, good thermal stability, and is suitable for high-frequency and microwave applications. FR-4 is a widely used epoxy glass fiber substrate with a medium dielectric constant and loss factor, low cost, high strength, easy to process, and suitable for low-frequency and medium-frequency applications. Rogers RT / Duroid series, such as RT / 6002, RT / 5880, Duroid 5870, etc., have lower losses and more stable dielectric constants, and are suitable for high-frequency and microwave circuits that require high performance. Ceramic substrates have a high dielectric constant and thermal stability, and are suitable for high-temperature and high-power applications, but have higher losses at high frequencies, and the cost and processing difficulty are also relatively high. Alumina has high thermal conductivity and thermal stability, and is suitable for high-power microwave applications, but has a relatively high dielectric constant and relatively large losses. Because the dielectric constant of PTFE is low, especially at high frequencies (such as the microwave band), this makes the signal loss smaller during transmission, which is beneficial to improving the performance and efficiency of the filter. And PTFE has excellent temperature stability and chemical stability, which means that under different environmental conditions, its dielectric properties change very little, and it can ensure that the filter performs consistently in various environments. Due to its low dielectric constant and low loss characteristics, PTFE is very suitable for designing high-frequency circuits such as microstrip lines and coupling structures, and can provide good high-frequency response and phase stability.

[0079] Therefore, using PTFE as the dielectric substrate can effectively reduce the energy loss of the signal during transmission, improve the stability and reliability of the filter, and is especially suitable for the filter design in communication devices that need to work in a high-frequency environment, such as mobile phones and WIFI routers.

[0080] According to an embodiment of the present invention, there is also provided a filtering switching method applied to any one of the above filters. Figure 15 It is a schematic flowchart of the filtering switching method provided by an embodiment of the present invention, as Figure 15 shown, and the method includes the following steps:

[0081] Step S1502, receive a filtering switching request.

[0082] In this step, the received filtering switching request can be to switch from the low-pass filtering state to the high-pass filtering state, or from the high-pass filtering state to the low-pass filtering state. Filters are usually applied in other devices, such as communication devices. By integrating the filter into the circuit board of the communication device, relevant software control can be set to automatically adjust the characteristics of the filter according to the communication environment or operating mode. For example, when the communication device is working in an environment with a large amount of low-frequency interference, the generated filtering switching request can be to request a switch to the high-pass filtering state to filter out unwanted low-frequency signals; on the contrary, when there is high-frequency interference, the generated filtering switching request can be to request a switch to the low-pass filtering mode. Filters can also be applied in WIFI routers. WIFI routers work in a complex wireless environment and may be interfered with by other wireless devices or electronic devices. The low-pass filter can block high-frequency interference signals, while the high-pass filter can block low-frequency noise or interference to ensure signal transmission within a specific frequency band. WIFI signals usually operate in the 2.4GHz and 5GHz frequency bands. The low-pass filter can be used for filtering 2.4GHz band signals, while the high-pass filter can be used for filtering 5GHz band signals. Switching the filtering characteristics can flexibly adapt to different frequency requirements and improve signal transmission efficiency.

[0083] Step S1504, based on the filtering switching request, adjust the working state of the main diode in the main tuning module of the filter through the main driving module and at the same time adjust the suppression state of the secondary tuning module through the secondary driving module to achieve the switching of the filtering state of the filter.

[0084] Based on the filtering switching request, adjust the working state of the main diode in the main tuning module of the filter through the main driving module and at the same time adjust the suppression state of the secondary tuning module through the secondary driving module to achieve the switching of the filtering state of the filter, including: in the case where the filtering switching request is for the filter to switch from the high-pass filtering state to the low-pass filtering state, control the driving module to make the main diode in the conducting state and control the secondary tuning module to allow high-frequency signals to pass through, and determine that the filter has switched to the low-pass filtering state.

[0085] Optionally, a forward voltage can be applied to the main diode by controlling the main driving module corresponding to the main diode. The main diode switches from the off state to the on state, and the secondary tuning module is controlled to allow high-frequency signals to pass through. At this time, the filter switches from the high-pass filtering state to the low-pass filtering state.

[0086] When the first stub is included in the secondary tuning module, the end of the first stub is grounded through the stub diode. When the filter is to be switched to the low-pass filtering state, a negative voltage can be controlled to be applied to the secondary driving module corresponding to the stub diode, thereby applying a voltage to the stub diode. The stub diode is in the off state. At this time, the secondary tuning module switches from controlling low-frequency signals to pass through to controlling high-frequency signals to pass through. At this time, the filter is in the high-pass filtering state.

[0087] When the filtering switching request is for the filter to switch from the low-pass filtering state to the high-pass filtering state, control the driving module to make the main diode in the off state and control the secondary tuning module to allow the low-frequency signal to pass through, and determine that the filter has switched to the high-pass filtering state.

[0088] Optionally, a negative voltage can be applied to the main diode by controlling the main driving module corresponding to the main diode, the main diode switches from the on state to the off state, and control the secondary tuning module to control the low-frequency signal to pass through. At this time, the filter switches from the low-pass filtering state to the high-pass filtering state.

[0089] When the first stub is included in the suppression circuit, the end of the first stub is grounded through the stub diode. When the filter is to be switched to the high-pass filtering state, the secondary driving module corresponding to the stub diode can be controlled to apply a positive voltage to the stub diode, and the stub diode is in the on state. At this time, the secondary tuning module switches from controlling the high-frequency signal to pass through to controlling the low-frequency signal to pass through, and at this time the filter is in the low-pass filtering state.

[0090] It should be noted that for the foregoing method embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps can be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0091] Through the description of the above embodiments, those skilled in the art can clearly understand that the filtering switching method according to the above embodiments can be implemented by means of software plus a necessary general hardware platform. Of course, it can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art can be embodied in the form of a software product. The computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes several instructions for causing a terminal device (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in the various embodiments of the present invention.

[0092] According to an embodiment of the present invention, there is also provided a filtering switching device for implementing any one of the above filtering switching methods.

[0093] According to an embodiment of the present invention, there is provided an electronic device including any one of the above filters and / or the above filtering switching device.

[0094] The serial numbers of the embodiments of the present invention above are only for description and do not represent the superiority or inferiority of the embodiments.

[0095] In the above embodiments of the present invention, the descriptions of the various embodiments have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0096] In several embodiments provided by the present application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only illustrative. For example, the division of the units can be a logical function division. In actual implementation, there can be other division methods. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed coupling or direct coupling or communication connection between each other can be through some interfaces. The indirect coupling or communication connection of units or modules can be in an electrical or other form.

[0097] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0098] In addition, the functional units in the various embodiments of the present invention can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0099] If the above integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. And the aforementioned storage medium includes: USB flash drives, read-only memories (ROMs), random access memories (RAMs), mobile hard disks, magnetic disks or optical discs and other various media that can store program codes.

[0100] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A filter, characterized in that: It includes a main driving module, a main tuning module, a sub-tuning module and a sub-driving module, wherein: The main driving module is connected to the signal input terminal and is used to control the working state of the main tuning module according to the first control signal; The main tuning module is connected to the main driving module and the signal output end, and is used to turn on or off the transmission signal, wherein when the main driving module controls the main tuning module to be in the on state, the filter is in the low-pass filtering state, and when the main driving module controls the main tuning module to be in the off state, the filter is in the high-pass filtering state; The secondary tuning module is connected to the signal input end and the signal output end, and is used to conduct the out-of-band signal of the transmission signal output by the main tuning module; The secondary driving module is connected to the secondary tuning module, and is used to switch on or off the connection between the secondary tuning module and the ground terminal according to a second control signal.

2. The filter according to claim 1, characterized in that The sub-tuning module includes a first branch, wherein a head end of the first branch is connected to the signal input end, and a terminal end of the first branch is connected to the sub-driving module and then grounded.

3. The filter according to claim 2, characterized in that The sub-driving module includes a sub-driving unit and a first branch diode, wherein: The sub-driving unit is used to control the working state of the first branch diode. When the sub-driving unit controls the first branch diode to be in a disconnected state, the first branch allows high-frequency signals to pass through. When the sub-driving unit controls the first branch diode to be in a conductive state, the first branch allows low-frequency signals to pass through.

4. The filter according to claim 2, characterized in that The first branch node is a microstrip branch node, and the first branch node includes a first component and a second component, wherein the width of the first component is smaller than the width of the second component.

5. The filter according to claim 1, characterized in that The main tuning module comprises a main diode, wherein a first end of the main diode is connected to the main driving module, and a second end of the main diode is connected to the signal output end.

6. The filter according to claim 1, characterized in that The main driving module, the main tuning module, the sub-tuning module and the sub-driving module form a first-stage filter, after which one or more other-stage filters including the main driving module, the main tuning module, the sub-tuning module and the sub-driving module are cascaded.

7. The filter according to any one of claims 1 to 6, characterized in that: It also includes a control module, wherein the first control signal is a bias voltage, and the control module is connected to the main driving module and is used to apply the bias voltage to the main driving module to control the working state of the main driving module.

8. A filter switching method, applied to the filter according to any one of claims 1 to 7, characterized in that: include: receiving a filter switching request; Based on the filter switching request, the working state of the main tuning module in the filter is adjusted by the main driving module, and the suppression state of the secondary tuning module is adjusted by the secondary driving module, so as to realize the filter state switching of the filter.

9. A filter switching device, characterized in that: Used to implement the filtering switching method described in claim 8 above.

10. An electronic device, characterized in that: It comprises the filter described in any one of claims 1 to 7 above, and / or the filter switching device described in claim 9 above.

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