CN215300592U - Band-pass filter circuit - Google Patents

Abstract

The utility model relates to the technical field of filters, in particular to a band-pass filter circuit, wherein, the band-pass filter comprises an input port, an output port, a low-pass filter network, a high-pass filter network and an adjusting resistor; the low-pass filter network and the high-pass filter network are connected in series between the input port and the output port; the high-pass filter network comprises a high-pass transmission main circuit, the high-pass transmission main circuit comprises a filter capacitor, and the adjusting resistor is connected with the filter capacitor in parallel. The utility model discloses a band-pass filter circuit, through setting up low pass filter network and high pass filter network, and set up the adjusting resistor who is parallelly connected in parallel with the filter capacitance of high pass transmission main road on high pass filter network, and realize restraining the ripple through the resistance size of this adjusting resistor of dynamic adjustment, and need not to set up extra balanced device, thereby make when not influencing the outband suppression degree, can also improve the flatness of plateau passband, realize wide passband, and the ripple reduces in the passband, thereby improve the performance of wave filter.

Description

Band-pass filter circuit

Technical Field

The utility model relates to a wave filter technical field especially relates to a band-pass filter circuit.

Background

In the application field of radio frequency communication, a filter is a device for filtering radio frequency waves, and a related filter circuit can allow radio frequency wave signals within a certain frequency band to pass through and simultaneously prevent radio frequency wave signals outside the frequency band from passing through. The filter can realize the maximization of the frequency spectrum utilization rate, but because the frequency bands are continuous, the interaction between the pass bands is obvious, the influence of the interaction frequency bands is large, and the phenomena of ripples and the like easily occur in the process, so that the flatness of the pass bands is influenced.

Therefore, how to eliminate the influence of the ripple in the filtering process of the continuous band-pass filter needs to be solved, so as to design a filter with higher performance.

SUMMERY OF THE UTILITY MODEL

An embodiment of the utility model provides a band-pass filter circuit to solve the too big problem of ripple that passes through the radio frequency signal in the filter circuit intermediate frequency band.

The utility model provides a pair of band-pass filter circuit, include: the device comprises an input port, an output port, a low-pass filter network, a high-pass filter network and a regulating resistor; the low-pass filter network and the high-pass filter network are connected in series between the input port and the output port; the high-pass filter network comprises a high-pass transmission main circuit, the high-pass transmission main circuit comprises a filter capacitor, and the adjusting resistor is connected with the filter capacitor in parallel.

Optionally, the main high-pass transmission path includes at least two filter capacitors connected in series, a high-pass connection node is disposed between two adjacent filter capacitors, a series resonant circuit is disposed between each high-pass connection node and a corresponding ground port, the series resonant circuit includes a series resonant inductor and a series resonant capacitor connected in series, and the adjusting resistor is connected in parallel with at least one filter capacitor.

Optionally, the main high-pass transmission path includes a first filter capacitor and a second filter capacitor connected in series, a first high-pass connection node is disposed on a connection path of the first filter capacitor and the second filter capacitor, a first series resonant circuit is disposed between the first high-pass connection node and a corresponding ground port, and the first series resonant circuit includes a first series resonant capacitor and a first series resonant inductor connected in series.

Optionally, the adjusting resistor is connected in parallel to the first filter capacitor, or the adjusting resistor is connected in parallel to the second filter capacitor.

Optionally, the adjusting resistor includes a first adjusting resistor and a second adjusting resistor, the first adjusting resistor is connected in parallel to the first filter capacitor, and the second adjusting resistor is connected in parallel to the second filter capacitor.

Optionally, the main high-pass transmission path includes a first filter capacitor, a second filter capacitor, and a third filter capacitor connected in series, a first high-pass connection node is disposed on a connection path of the first filter capacitor and the second filter capacitor, a second high-pass connection node is disposed on a connection path of the second filter capacitor and the third filter capacitor, a first series resonant circuit is disposed between the first high-pass connection node and the ground port, a second series resonant circuit is disposed between the second high-pass connection node and the ground port, the first series resonant circuit includes a first series resonant capacitor and a first series resonant inductor connected in series, and the second series resonant circuit includes a second series resonant capacitor and a second series resonant inductor connected in series.

Optionally, the adjusting resistor is connected in parallel to the first filter capacitor, and/or the adjusting resistor is connected in parallel to the second filter capacitor, or the adjusting resistor is connected in parallel to the third filter capacitor.

Optionally, the adjusting resistor includes a first adjusting resistor, a second adjusting resistor, and a third adjusting resistor, the first adjusting resistor is connected in parallel to the first filter capacitor, the second adjusting resistor is connected in parallel to the second filter capacitor, and the third adjusting resistor is connected in parallel to the third filter capacitor.

Optionally, the band-pass filter circuit further includes a first inductor, and the first inductor is connected in series with the adjusting resistor and then connected in parallel with the filter capacitor.

Optionally, the low-pass filter network includes a main low-pass transmission path, the main low-pass transmission path includes two first parallel resonant circuits and two second parallel resonant circuits connected in series, an input end of the first parallel resonant circuit is provided with a first low-pass connection node, a connection path between the first parallel resonant circuit and the second parallel resonant circuit is provided with a second low-pass connection node, an output end of the second parallel resonant circuit is provided with a third low-pass connection node, a first capacitor circuit is provided between the first low-pass node and a ground port, a second capacitor circuit is provided between the second low-pass node and the ground port, and a third capacitor circuit is provided between the third low-pass node and the ground port;

the first parallel resonant circuit includes a first parallel resonant capacitor and a second parallel resonant inductor connected in parallel, and the second parallel resonant circuit includes a second parallel resonant capacitor and a second parallel resonant inductor connected in parallel.

The utility model discloses a band-pass filter circuit, through between band-pass filter circuit's input port and output port, set up series connection's low pass filter network and high pass filter network, and to adjust resistance and high pass filter network's high pass transmission main road on filter capacitor parallelly connected, thereby realize suppressing the ripple of the radio frequency signal in the frequency band in the band-pass filter circuit through adjusting the resistance size of this regulation resistance, and need not additionally to set up the equalizer, thereby make when not influencing the radio frequency signal that suppresses outside the frequency band, can also improve the flatness of the radio frequency signal in the frequency band; the double effects of reducing in-band ripples and inhibiting out-band signals are achieved, and the performance of the band-pass filter circuit is further improved.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments of the present invention will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic circuit diagram of a bandpass filter circuit according to an embodiment of the present invention;

fig. 2 is another circuit diagram of a band-pass filter circuit according to an embodiment of the present invention;

fig. 3 is another circuit diagram of the band-pass filter circuit according to an embodiment of the present invention;

fig. 4 is another circuit diagram of the band-pass filter circuit according to an embodiment of the present invention;

fig. 5 is another circuit diagram of the band-pass filter circuit according to an embodiment of the present invention;

fig. 6 is another circuit schematic diagram of a band-pass filter circuit according to an embodiment of the present invention;

fig. 7 is another circuit schematic diagram of a band-pass filter circuit according to an embodiment of the present invention;

fig. 8 is another circuit diagram of the band-pass filter circuit according to an embodiment of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, of the embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

It is to be understood that the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity to indicate like elements throughout.

It will be understood that when an element or layer is referred to as being "on …," "adjacent to …," "connected to" or "coupled to," "connected with …" other elements or layers, it can be directly on, adjacent to, connected to, or coupled to the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on …," "directly adjacent to …," "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. It will be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.

Spatially relative terms, such as "under …", "under …", "below", "under …", "over …", "over", and the like, may be used herein for ease of description to describe one element or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, then elements or features described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary terms "below …" and "below …" can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial descriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.

In order to provide a thorough understanding of the present invention, detailed structures and steps will be provided in the following description so as to explain the technical solution provided by the present invention. The preferred embodiments of the present invention are described in detail below, however, other embodiments of the present invention are possible in addition to these detailed descriptions.

The utility model relates to a technical field of wave filter, concretely relates to band-pass filter circuit. In an application scenario, the inventor finds that the existing filter has continuous frequency bands, obvious interaction between passbands and large interaction frequency band influence, and ripples and other phenomena are easy to occur in the process, so as to influence the flatness of the passbands, and in order to solve the above problems, the inventor has the inventive concept of the present application, which will be specifically explained by the following embodiments:

in one embodiment, as shown in fig. 1, the band pass filter circuit of the present invention may specifically include: the input port IN, the output port OUT, the low-pass filter network 10, the high-pass filter network 20 and the adjusting resistor R.

The low-pass filter network 10 and the high-pass filter network 20 are connected IN series, and the low-pass filter network 10 and the high-pass filter network 20 connected IN series are connected between the input port IN and the output port OUT of the band-pass filter circuit. It should be noted that the order of the series connection of the low-pass filter network 10 and the high-pass filter network 20 may not be required, that is, the input end of the low-pass filter network 10 may be connected to the input port IN, the output end of the low-pass filter network 20 may be connected to the input end of the high-pass filter network 20, and the output end of the high-pass filter network 20 may be connected to the output port OUT, or the input end of the high-pass filter network 20 may be connected to the input port IN, the output end of the high-pass filter network 20 may be connected to the input end of the low-pass filter network 10, and the output end of the low-pass filter network 10 may be connected to the output port OUT; the selection can be specifically carried out according to the actual scene. The low-pass filter network 10 may be any type of filter network, and the high-pass filter network 20 may also be any type of filter network.

Specifically, the high-pass filter network 20 includes a high-pass transmission main circuit, and the high-pass transmission main circuit includes a filter capacitor C, that is, the high-pass filter network 20 may be a circuit including only one filter capacitor, or may be a circuit including capacitors and inductors connected in series or in parallel in any connection manner. The high pass filter network 20 may be a first order filter network, a second order filter network, a third order filter network, or any order filter network. The adjusting resistor R is connected in parallel with at least one filter capacitor C on the main high-pass transmission path in the high-pass filter network 20.

In an application scenario, the resistance value of the adjusting resistor R preferably ranges from: 0.5 ohm to 5 ohm, which can be set by user according to the actual situation, it should be noted that the larger the resistance of the adjusting resistor R is, the better the effect of suppressing the ripple of the radio frequency signal in the frequency band of the band-pass filter circuit is, but the larger the loss of the band-pass filter circuit is. In practical application, the ripple suppression effect and the loss can be balanced according to actual requirements, and the adjusting resistor R with the optimal resistance value can be selected.

Further, the adjusting resistor R can also be set to be an adjustable resistor, so that the resistance of the adjusting resistor R can be adjusted according to actual requirements in practical application, and the best effect of ripple suppression can be achieved by adjusting the resistance of the adjusting resistor R.

IN the band-pass filter circuit IN the above embodiment, the low-pass filter network 10 and the high-pass filter network 20 connected IN series are arranged between the input port IN and the output port OUT of the band-pass filter circuit, the adjusting resistor is connected IN parallel with the filter capacitor on the main high-pass transmission path of the high-pass filter network, and the ripple of the radio-frequency signal IN the frequency band IN the band-pass filter circuit is suppressed by adjusting the resistance of the adjusting resistor R, so that an additional equalizer is not required, and the flatness of the radio-frequency signal IN the frequency band can be improved while the suppression of the radio-frequency signal outside the frequency band is not affected; the double effects of reducing in-band ripples and inhibiting out-band signals are achieved, and the performance of the band-pass filter circuit is further improved.

In one embodiment, as shown in fig. 2, the main high-pass transmission path includes at least two filter capacitors C connected in series.

Specifically, the at least two filter capacitors C connected in series may include two filter capacitors C connected in series, or three filter capacitors C connected in series, or four filter capacitors C connected in series, and the like, and the specific number is not limited. A high-pass connection node (not shown in the figure) is arranged between two adjacent filter capacitors C, a series resonance circuit is arranged between each high-pass connection node and the corresponding ground port, the series resonance circuit comprises a series resonance inductor L and a series resonance capacitor C4 which are connected in series, and the adjusting resistor R is connected in parallel with at least one filter capacitor C.

Illustratively, for example, two filter capacitors C may be currently provided, in one embodiment, as shown in fig. 3, the high-pass transmission main circuit includes a first filter capacitor C1 and a second filter capacitor C2 connected in series, a first high-pass connection node is provided on a connection path of the first filter capacitor C1 and the second filter capacitor C2, a first series resonant circuit is provided between the first high-pass connection node and the corresponding ground port, and the first series resonant circuit includes a first series resonant capacitor C4 and a first series resonant inductor L connected in series.

In which the tuning resistor R is connected in parallel with at least one filter capacitor C, and in one embodiment, as shown in fig. 2 and 3, the tuning resistor R is connected in parallel with the first filter capacitor C1, and/or the tuning resistor R is connected in parallel with the second filter capacitor C2. Specifically, the adjusting resistor R may include one or more, for example, the adjusting resistor R may be connected in parallel with the first filter capacitor C1, or the adjusting resistor R may be connected in parallel with the second filter capacitor C2; alternatively, two adjusting resistors R may be provided, and the two adjusting resistors R may be connected in parallel with the two first filtering capacitors C1 and the second filtering capacitor C2, respectively.

In the above embodiment, at least two filter capacitors C connected in series are provided, a high-pass connection node is provided between two adjacent filter capacitors C, and a series resonant circuit is provided between the high-pass connection node and a corresponding ground port, so that the adjusting resistor R is connected in parallel with at least one filter capacitor C, and thus, the adjusting resistor R can perform ripple suppression on a radio frequency signal in a frequency band in a band-pass filter circuit composed of a third-order high-pass filter network, so as to improve the applicability and performance of the band-pass filter circuit.

In one embodiment, as shown in fig. 4-6, the main high-pass transmission circuit includes a first filter capacitor C1, a second filter capacitor C2, and a third filter capacitor C3 connected in series, that is, in this embodiment, three filter capacitors C may be further provided, specifically, a first high-pass connection node is provided on a connection path of the first filter capacitor C1 and the second filter capacitor C2, a second high-pass connection node is provided on a connection path of the second filter capacitor C2 and the third filter capacitor C3, a first series resonant circuit is provided between the first high-pass connection node and the ground port, a second series resonant circuit is provided between the second high-pass connection node and the ground port, the first series resonant circuit includes a first series resonant capacitor C4 and a first series resonant inductor L1 connected in series, and the second series resonant circuit includes a second series resonant capacitor C5 and a second series resonant inductor L2 connected in series.

Based on the first filter capacitor C1, the second filter capacitor C2, and the third filter capacitor C3 provided in the foregoing embodiments, correspondingly, in an embodiment, the adjusting resistor R is connected in parallel with the first filter capacitor C1, and/or the adjusting resistor R is connected in parallel with the second filter capacitor C2, or the adjusting resistor R is connected in parallel with the third filter capacitor C3. Illustratively, as shown in fig. 4, for example, a regulating resistor R is currently provided, which may be connected in parallel with the first filter capacitor C1; alternatively, the adjusting resistor R may be connected in parallel with the second filter capacitor C2; alternatively, the adjusting resistor R may be connected in parallel with the third filter capacitor C3; alternatively, as shown in fig. 5, two adjusting resistors R may be further provided, where the two adjusting resistors R include a first adjusting resistor R1 and a second adjusting resistor R2, and specifically, the first adjusting resistor R1 and the second adjusting resistor R2 are connected in parallel to the first filter capacitor C1 and the second filter capacitor C2, respectively; or, the first adjusting resistor R1 and the second adjusting resistor R2 are respectively connected in parallel with the first filter capacitor C1 and the third filter capacitor C3; or, the first adjusting resistor R1 and the second adjusting resistor R2 are respectively connected in parallel with the second filter capacitor C2 and the third filter capacitor C3; alternatively, as shown in fig. 6, three adjusting resistors R may be further provided, where the three adjusting resistors R include a first adjusting resistor R1, a second adjusting resistor R2, and a third adjusting resistor R3, and specifically, the first adjusting resistor R1, the second adjusting resistor R2, and the third adjusting resistor R3 may be connected in parallel to the first filter capacitor C1, the second filter capacitor C2, and the third filter capacitor C3, respectively. It should be noted that it is only necessary to ensure that the adjusting resistor R is connected in parallel with at least one filter capacitor in the high-pass filter circuit.

In the above embodiment, three first, second and third filter capacitors C1, C2 and C3 are provided, and a first high-pass connection node and a second high-pass connection node are provided between two adjacent filter capacitors C, a first series resonant circuit is provided between the first high-pass connection node and a corresponding ground port, and a second series resonant circuit is provided between the second high-pass connection node and a corresponding ground port, so that at least one adjusting resistor R is connected in parallel with at least one filter capacitor C, so that the adjusting resistor R performs ripple suppression on radio frequency signals in a frequency band in a band-pass filter circuit composed of a fifth-order high-pass filter network, thereby improving applicability and performance of the band-pass filter circuit.

It should be noted that, in addition to the two embodiments described above, two filter capacitors C and one series resonant circuit are arranged in series, and three filter capacitors C and two series resonant circuits are arranged in series, and the high-pass filter network that forms the band-pass filter circuit may further include more filter capacitors C connected in series and series resonant circuits arranged correspondingly.

In one embodiment, as shown in fig. 7, the band-pass filter circuit further includes a first inductor L3, and the first inductor L3 is connected in series with the regulating resistor R and then connected in parallel with the filter capacitor C. For example, a regulating resistor R is currently provided, the first inductor L3 may be connected in series with the regulating resistor R, and then the regulating resistor R and the first inductor L3 connected in series are connected in parallel with the filter capacitor C as a whole, it can be understood that the band-pass filter circuit may further include a plurality of first inductors L3, where one first inductor L3 is connected in series with one regulating resistor R and then connected in parallel with a corresponding one of the filter capacitors C. When the high-pass main path of the high-pass filter network includes a plurality of filter capacitors C, and each filter capacitor C is connected in parallel with a corresponding adjusting resistor R, each first inductor L3 may be connected in series with a corresponding adjusting resistor R and then connected in parallel with a corresponding filter capacitor C, for avoiding redundancy, refer to the description of the above embodiments, which will not be described herein,

in the above embodiment, the first inductor L3 is connected in series with the adjusting resistor R, and then connected in parallel with the filter capacitor C, and the adjusting resistor R is connected in series with the first inductor L3 and then connected in parallel with the filter capacitor C in this embodiment, so that the effect of suppressing out-of-band signals can be ensured while the ripple of the radio frequency signals in the intermediate frequency band of the band-pass filter circuit is suppressed.

IN one embodiment, as shown IN fig. 1-6, the input of the low pass filter network 10 is connected to the input port IN, the output of the low pass filter network 10 is connected to the input of the high pass filter network 20, and the output of the high pass filter network 20 is connected to the output port OUT. That is, a band-pass filter network of the low-pass filter network 10 to the high-pass filter network 20 is provided in this embodiment.

In one embodiment, as shown in fig. 8, the low-pass filter network 10 includes a low-pass transmission main circuit, the low-pass transmission main circuit includes two series-connected first parallel resonant circuits and second parallel resonant circuits, an input end of the first parallel resonant circuit is provided with a first low-pass connection node, a connection path between the first parallel resonant circuit and the second parallel resonant circuit is provided with a second low-pass connection node, an output end of the second parallel resonant circuit is provided with a third low-pass connection node, a first capacitor circuit is provided between the first low-pass node and a ground port, a second capacitor circuit is provided between the second low-pass node and the ground port, and a third capacitor circuit is provided between the third low-pass node and the ground port, and specifically, the first capacitor circuit includes a capacitor C8, the second capacitor circuit includes a capacitor C9, and the third capacitor circuit includes a capacitor C10. Specifically, the first parallel resonant circuit includes a first parallel resonant capacitor C6 and a second parallel resonant inductor L3 connected in parallel, and the second parallel resonant circuit includes a second parallel resonant capacitor C7 and a second parallel resonant inductor L4 connected in parallel.

IN the low-pass filter network IN the above embodiment, by providing the first parallel resonant circuit and the second parallel resonant circuit connected IN series, and providing the low-pass connection nodes between the input port IN and the parallel resonant circuit, between the adjacent parallel resonant circuits, and between the parallel resonant circuit and the output port OUT, and providing the capacitor circuit between each low-pass connection node and the corresponding ground terminal, it is possible to implement multi-order low-pass filtering, so as to improve the applicability and performance of the low-pass filtering.

In addition, it should be noted that the multi-stage network configured for the low-pass filter network is only used for example, and is not limited in practice, and may be specifically configured according to an actual scene.

In one embodiment, the low pass filter network 10 and the high pass filter network 20 may each employ an elliptic function filter network. It is understood that elliptic function filtering is also called a coulter filter, and elliptic function filtering is a filter network with ripples such as pass band and stop band. Compared with other types of filter networks, the elliptic filter network has the minimum passband and stopband fluctuation under the condition of the same order, so that the relatively small stopband fluctuation can be realized by setting the networks with fewer orders, the overall architecture of the bandpass filter network is simplified, and the applicability of the bandpass filter network is improved.

In one embodiment, the present invention may further include a band pass filter (not shown in the figure), specifically, the band pass filter includes the band pass filter circuit of any of the above embodiments. The band-pass filter in the embodiment can inhibit the ripple of the band-pass filter through the band-pass filter circuit in the embodiment, and the performance of the band-pass filter is improved.

The above-mentioned embodiments are only used for illustrating the technical solution of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.

Claims (10)

1. A band-pass filter circuit, comprising: the device comprises an input port, an output port, a low-pass filter network, a high-pass filter network and a regulating resistor; the low-pass filter network and the high-pass filter network are connected in series between the input port and the output port; the high-pass filter network comprises a high-pass transmission main circuit, the high-pass transmission main circuit comprises a filter capacitor, and the adjusting resistor is connected with the filter capacitor in parallel.

2. The band-pass filter circuit according to claim 1, wherein the main high-pass transmission path includes at least two filter capacitors connected in series, a high-pass connection node is provided between two adjacent filter capacitors, a series resonant circuit is provided between each high-pass connection node and a ground port, the series resonant circuit includes a series resonant inductor and a series resonant capacitor connected in series, and the adjusting resistor is connected in parallel with at least one of the filter capacitors.

3. The band-pass filter circuit according to claim 2, wherein the high-pass transmission main path includes a first filter capacitor and a second filter capacitor connected in series, a first high-pass connection node is provided on a connection path of the first filter capacitor and the second filter capacitor, a first series resonant circuit is provided between the first high-pass connection node and a ground port, and the first series resonant circuit includes a first series resonant capacitor and a first series resonant inductor connected in series.

4. The bandpass filter circuit according to claim 3, wherein the adjusting resistor is connected in parallel with the first filter capacitor, or wherein the adjusting resistor is connected in parallel with the second filter capacitor.

5. The bandpass filter circuit of claim 3 wherein the tuning resistor comprises a first tuning resistor and a second tuning resistor, the first tuning resistor being connected in parallel with the first filter capacitor and the second tuning resistor being connected in parallel with the second filter capacitor.

6. The band-pass filter circuit according to claim 2, wherein the main high-pass transmission path includes a first filter capacitor, a second filter capacitor and a third filter capacitor connected in series, a first high-pass connection node is arranged on a connection path of the first filter capacitor and the second filter capacitor, a second high-pass connection node is arranged on a connection path of the second filter capacitor and the third filter capacitor, a first series resonant circuit is provided between the first high-pass connection node and a ground port, a second series resonant circuit is provided between the second high-pass connection node and a ground port, the first series resonant circuit includes a first series resonant capacitor and a first series resonant inductor connected in series, the second series resonant circuit includes a second series resonant capacitor and a second series resonant inductor connected in series.

7. The bandpass filter circuit according to claim 6, wherein the adjusting resistor is connected in parallel with the first filter capacitor, or wherein the adjusting resistor is connected in parallel with the second filter capacitor, or wherein the adjusting resistor is connected in parallel with the third filter capacitor.

8. The bandpass filter circuit of claim 6 wherein the tuning resistor comprises a first tuning resistor connected in parallel with the first filter capacitor, a second tuning resistor connected in parallel with the second filter capacitor, and a third tuning resistor connected in parallel with the third filter capacitor.

9. The bandpass filter circuit according to claim 1, wherein the bandpass filter circuit further comprises a first inductor connected in series with the regulating resistor and then connected in parallel with the filter capacitor.

10. The band-pass filter circuit according to claim 1, wherein the low-pass filter network includes a low-pass transmission main circuit including two first and second parallel resonant circuits connected in series, an input end of the first parallel resonant circuit is provided with a first low-pass connection node, a connection path between the first and second parallel resonant circuits is provided with a second low-pass connection node, an output end of the second parallel resonant circuit is provided with a third low-pass connection node, a first capacitance circuit is provided between the first low-pass connection node and a ground port, a second capacitance circuit is provided between the second low-pass connection node and a ground port, and a third capacitance circuit is provided between the third low-pass connection node and a ground port;

the first parallel resonant circuit includes a first parallel resonant capacitor and a second parallel resonant inductor connected in parallel, and the second parallel resonant circuit includes a second parallel resonant capacitor and a second parallel resonant inductor connected in parallel.

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