CN214672907U - Band-pass filter - Google Patents

Abstract

The utility model discloses a band-pass filter, which comprises a substrate, a port electrode arranged on the surface of the substrate and a filter circuit arranged in the substrate; the port electrode comprises an input port electrode, an output port electrode and a grounding port electrode; the filter circuit comprises a first microstrip conductor layer, a second microstrip conductor layer, a third microstrip conductor layer, a first plane conductor layer and a second plane conductor layer which are sequentially arranged in a laminated manner; the first microstrip conductor layer, the second microstrip conductor layer and the second planar conductor layer are all electrically connected with the ground port electrode. Through right the utility model discloses a filter laminated structure's design makes it have simple structure, small, the insertion loss advantage little and the stop band restraines height.

Description

Band-pass filter

Technical Field

The embodiment of the utility model provides a relate to wave filter technical field, especially relate to a band-pass filter.

Background

Filters are important components essential in communication technology, and serve to select signals, provide signal transmission in the pass band, provide signal attenuation in the stop band, and play a crucial role in many systems, with the performance of the filter directly affecting the performance of the entire system. With the rapid development of electronic communication technology, the frequency of filter application is higher and higher in the coming of 5G communication technology, and the miniaturization, high performance, high integration and low cost of devices are the great trend.

Distributed filters of conventional construction. For example: planar coupled microwave filters implemented by microstrip lines, coaxial lines, strip lines, waveguides, etc. have not been able to meet the trend of devices toward miniaturization due to their large size.

Disclosure of Invention

In view of this, the present invention provides a band-pass filter, which solves the technical problems of the prior art that the size of the filter is too large and the miniaturization and high performance of the device cannot be achieved by designing the layered structure of the filter and the distribution of the internal components.

The utility model provides a band-pass filter, which comprises a substrate, a port electrode arranged on the surface of the substrate and a filter circuit arranged in the substrate; the port electrode comprises an input port electrode, an output port electrode and a grounding port electrode;

the filter circuit comprises a first microstrip conductor layer, a second microstrip conductor layer, a third microstrip conductor layer, a first plane conductor layer and a second plane conductor layer which are sequentially arranged in a laminated manner; the first microstrip conductor layer, the second microstrip conductor layer and the second planar conductor layer are all electrically connected with the ground port electrode;

the second microstrip conductor layer comprises a first conductor subsection and a second conductor subsection, the third microstrip conductor layer comprises a third conductor subsection and a fourth conductor subsection, and the first planar conductor layer comprises a fifth conductor subsection, a sixth conductor subsection, and a seventh conductor subsection;

the filter circuit comprises a first resonance unit, a second resonance unit and a third resonance unit, and the first resonance unit, the second resonance unit and the third resonance unit are coupled in pairs; the first resonance unit comprises a first inductor and a first capacitor, the second resonance unit comprises a second inductor and a second capacitor, and the third resonance unit comprises a third inductor and a third capacitor;

the first inductor comprises the first conductor subsection and the fifth conductor subsection, and the first capacitor comprises the fifth conductor subsection and the second planar conductor layer; the second inductor comprises the first microstrip conductor layer and the sixth conductor subsection, and the second capacitor comprises the sixth conductor subsection and the second planar conductor layer; the third inductor comprises the second conductor subsection and the seventh conductor subsection, and the third capacitor comprises the seventh conductor subsection and the second planar conductor layer;

the band-pass filter also comprises an input electrode and an output electrode, wherein the input electrode is respectively and electrically connected with the filter circuit and the input port electrode, and the output electrode is respectively and electrically connected with the filter circuit and the output port electrode; the input electrode comprises the third conductor subsection and the output electrode comprises the fourth conductor subsection.

Optionally, the bandpass filter further includes a first conductive pillar, a second conductive pillar, and a third conductive pillar;

the first conductive pillar is for electrically connecting the first conductor subsection and the fifth conductor subsection;

the second conductive pillar is for electrically connecting the first microstrip conductor layer and the sixth conductor subsection;

the third conductive pillar is for electrically connecting the second conductor subsection and the seventh conductor subsection.

Optionally, the input electrode is electrically connected to the first conductive pillar, and the output electrode is electrically connected to the third conductive pillar.

Optionally, the first conductive pillars, the second conductive pillars, and the third conductive pillars are arranged in a straight line.

Optionally, the first conductor subsection includes a plurality of first conductor segments arranged in succession, and the extending direction of any two connected first conductor segments is vertical;

the second conductor subsection comprises a plurality of second conductor segments which are sequentially connected, and the extending directions of any two connected second conductor segments are vertical;

the first microstrip conductor layer includes a third conductor section, and the first conductor section and the second conductor section are symmetrically disposed on two sides of the third conductor section.

Optionally, any two conductor layers of the first microstrip conductor layer, the second microstrip conductor layer, the third microstrip conductor layer, the first planar conductor layer, and the second planar conductor layer are disposed in parallel.

Optionally, the ground port electrode includes a first ground port electrode and a second ground port electrode;

the first ground port electrode is arranged on a first surface of the substrate, the second ground port electrode is arranged on a second surface of the substrate, and the first surface and the second surface are oppositely arranged;

the input port electrode is arranged on a third surface of the base body, the output port electrode is arranged on a fourth surface of the base body, and the third surface and the fourth surface are oppositely arranged.

Optionally, the substrate has an extension length in the first direction of L1, an extension length in the second direction of L2, and an extension length in the third direction of L3;

wherein L1 is more than or equal to 1.9mm and less than or equal to 2.1mm, L2 is more than or equal to 1.2mm and less than or equal to 1.3mm, and L3 is more than or equal to 0.6mm and less than or equal to 0.7 mm;

any two directions of the first direction, the second direction and the third direction are perpendicular to each other.

Optionally, the passband range of the band pass filter is 3400MHz-3600 MHz.

Optionally, the substrate comprises a low temperature co-fired ceramic substrate.

The utility model provides a band pass filter, first inductance and first electric capacity form first resonance unit, and second inductance and second electric capacity form second resonance unit, and third inductance and third electric capacity form third resonance unit, and each resonance unit comprises the resonance inductance and the resonance electric capacity of novel structure, mutual coupling between every resonance unit to realize tertiary filtering characteristic. Compared with the similar filter, the filter has the advantages of small size, small insertion loss, high stop band suppression and the like. Further, the embodiment of the utility model provides a band pass filter has used multilayer medium base plate, make full use of three-dimensional multilayer space to showing and having reduced the required volume of component, having overcome that traditional wave filter structure is complicated, defect that the size is big has reached under the prerequisite that satisfies filtering performance, realizing under wave filter simple structure and the small beneficial effect.

Drawings

In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, a brief description is given below of the drawings required for describing the embodiments. It should be clear that the described figures are only drawings of some of the embodiments of the invention to be described, not all, and that for a person skilled in the art, other figures can be derived from these figures without inventive effort.

Fig. 1 is a schematic structural diagram of a band-pass filter according to an embodiment of the present invention;

fig. 2 is a front view of a layered structure of a bandpass filter according to an embodiment of the present invention;

fig. 3 is a schematic circuit diagram of a resonant unit of a band-pass filter according to an embodiment of the present invention;

fig. 4 is a top view of a microstrip conductor layer in a bandpass filter according to an embodiment of the present invention;

fig. 5 is a front view of a microstrip conductor layer in a bandpass filter according to an embodiment of the present invention;

fig. 6 is an S-parameter curve of a band-pass filter according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail through the following embodiments with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, not all embodiments, and all other embodiments obtained by those skilled in the art without creative efforts based on the embodiments of the present invention all fall into the protection scope of the present invention.

Fig. 1 is a schematic structural diagram of a band pass filter provided by an embodiment of the present invention, fig. 2 is a front view of a layered structure of a band pass filter provided by an embodiment of the present invention, fig. 3 is a schematic circuit diagram of a resonance unit of a band pass filter provided by an embodiment of the present invention, which is shown in fig. 1-3, in combination with fig. 1, the embodiment of the present invention provides a band pass filter, which can be applied in communication technology and plays a role of signal selection, and the band pass filter includes a base body 1, a port electrode 3 disposed on the surface of the base body 1, and a filter circuit 2 disposed in the base body 1; the port electrode 3 includes an input port electrode 321, an output port electrode 322, and ground port electrodes 331 and 332.

The filter circuit 2 comprises a first microstrip conductor layer 21, a second microstrip conductor layer 22, a third microstrip conductor layer 23, a first plane conductor layer 24 and a second plane conductor layer 25 which are sequentially arranged in a laminated manner; the first microstrip conductor layer 21, the second microstrip conductor layer 22, and the second planar conductor layer 25 are all electrically connected to the ground port electrodes 331 and 332.

The second microstrip conductor layer 22 includes a first conductor subsection 221 and a second conductor subsection 222, the third microstrip conductor layer 23 includes a third conductor subsection 231 and a fourth conductor subsection 232, and the first planar conductor layer 24 includes a fifth conductor subsection 241, a sixth conductor subsection 242, and a seventh conductor subsection 243.

The filter circuit comprises a first resonance unit 1A, a second resonance unit 2A and a third resonance unit 3A, and the first resonance unit 1A, the second resonance unit 2A and the third resonance unit 3A are coupled in pairs; the first resonance unit 1A includes a first inductance 1L and a first capacitance 1C, the second resonance unit 2A includes a second inductance 2L and a second capacitance 2C, and the third resonance unit 3A includes a third inductance 3L and a third capacitance 3C.

In connection with the schematic structural diagram and the front view of the layered structure of the bandpass filter provided in fig. 2, the first inductor 1L comprises a first conductor subsection 221 and a fifth conductor subsection 241, the first capacitor 1C comprises a fifth conductor subsection 241 and a second planar conductor layer 25; the second inductor 2L comprises the first microstrip conductor layer 21 and the sixth conductor subsection 242, and the second capacitor 2C comprises the sixth conductor subsection 242 and the second planar conductor layer 25; the third inductance 3L comprises a second conductor subsection 222 and a seventh conductor subsection 243 and the third capacitance 3C comprises a seventh conductor subsection 243 and a second planar conductor layer 25.

In conjunction with the front view of the layered structure of the bandpass filter provided in fig. 1 and 2, the bandpass filter further includes an input electrode electrically connected to the filter circuit 2 and the input port electrode 321, respectively, and an output electrode electrically connected to the filter circuit 2 and the output port electrode 322, respectively; the input electrode comprises a third conductor subsection 231 and the output electrode comprises a fourth conductor subsection 232.

The band-pass filter has a pass band and a stop band, and plays a role in signal selection in communication technology by transmitting signals with specific frequencies in the pass band and attenuating signals except the signals with the specific frequencies in the stop band.

Include filter circuit 2 of wave filter in the base member 1 of wave filter, filter circuit 2 includes a plurality of resonance units, the embodiment of the utility model provides a use filter circuit 2 to include 3 resonance units and explain as the example, first resonance unit 1A, second resonance unit 2A and third resonance unit 3A promptly, two liang of couplings of first resonance unit 1A, second resonance unit 2A and third resonance unit 3A unit to realize tertiary filtering characteristic. Specifically, each resonant unit may include an inductor and a capacitor, for example, the first resonant unit 1A includes a first inductor 1L and a first capacitor 1C, the second resonant unit 2A includes a second inductor 2L and a second capacitor 2C, and the third resonant unit 3A includes a third inductor 3L and a third capacitor 3C, that is, each resonant unit forms an LC resonant filtering unit, which ensures that the resonant filtering unit has a simple structure and a good filtering effect. Further, the filter unit 2 includes a plurality of layered structures stacked in sequence, specifically, the filter circuit 2 includes a plurality of microstrip conductor layers and a planar conductor layer, and the microstrip conductor layers and the planar conductor layers in the layered structures of the filter circuit 2 form a filter network structure, which can effectively transmit signals. The three-level resonance unit and the multilayer laminated structure of the filter circuit 2 are combined, namely, the three-level resonance unit is comprehensively arranged in the multilayer laminated structure by the filter circuit, namely, an active passive device is arranged in the laminated substrate, so that the mutual interference is small, the element density can be improved, and the size miniaturization of the filter is realized. Further, the port electrode 3 is disposed on the surface of the filter substrate, and the input port electrode 321 and the output port electrode 322 included in the port electrode 3 are used for connecting the filter with other devices to realize signal selection; the ground port electrodes 331 and 332 are grounding means for completing the in-substrate filter circuit.

Next, how the three-stage resonant cells in the filter circuit are integrally arranged in the multilayer layered structure will be described in detail.

With continued reference to fig. 2, the filter circuit 2 includes a first microstrip conductor layer 21, a second microstrip conductor layer 22, a third microstrip conductor layer 23, a first planar conductor layer 24, and a second planar conductor layer 25, which are sequentially stacked; the first microstrip conductor layer 21, the second microstrip conductor layer 22, and the second planar conductor layer 25 are all electrically connected to the ground port electrodes 331 and 332. The second microstrip conductor layer 22 includes a first conductor subsection 221 and a second conductor subsection 222, the third microstrip conductor layer 23 includes a third conductor subsection 231 and a fourth conductor subsection 232, and the first planar conductor layer 24 includes a fifth conductor subsection 241, a sixth conductor subsection 242, and a seventh conductor subsection 243. Corresponding to the first, second and third resonator cells 1A, 2A, 3A, the first inductance 1L comprises a first conductor subsection 221 and a fifth conductor subsection 241, the first capacitance 1C comprises a fifth conductor subsection 241 and a second planar conductor layer 25; the second inductor 2L comprises the first microstrip conductor layer 21 and the sixth conductor subsection 242, and the second capacitor 2C comprises the sixth conductor subsection 242 and the second planar conductor layer 25; the third inductance 3L comprises a second conductor subsection 222 and a seventh conductor subsection 243 and the third capacitance 3C comprises a seventh conductor subsection 243 and a second planar conductor layer 25. Thus, the filter circuit 2 integrates a three-level resonance filter structure and a multilayer layered structure, and realizes a three-level filter characteristic. Compared with the similar filter, the three-dimensional multilayer space is fully utilized, so that the volume required by elements is obviously reduced, and the beneficial effects of simple structure and small volume of the filter are realized.

To sum up, the embodiment of the utility model provides a band pass filter, the resonance unit that has comprises resonance inductance and resonance electric capacity of novel structure, and resonance inductance and resonance electric capacity form in the multilayer piles up the filter circuit structure that constitutes in proper order, and two liang of couplings between the resonance unit constitute tertiary filtering characteristic. The embodiment of the utility model provides a band pass filter has synthesized tertiary resonance filtering structure and multilayer lamellar structure, realizes under the prerequisite of advantages such as tertiary filtering characteristic, insertion loss are little, stop band suppression height, compares with the wave filter of the same kind, make full use of three-dimensional multilayer space to showing and having reduced the required volume of component, having overcome that traditional wave filter structure is complicated, the defect that the size is big realizes wave filter simple structure and small beneficial effect.

On the basis of the above embodiment, the substrate 1 may comprise a low temperature co-fired ceramic substrate.

Exemplarily, Low Temperature Co-fired Ceramic (Low Temperature Co-fired Ceramic LTCC), can form the high-density device of the complementary interference of three-dimensional space, after sintering greatly reduced the volume of device, set up the base member 1 and include the Low Temperature Co-fired Ceramic base member and can guarantee consequently the utility model discloses the band pass filter that the embodiment provided has advantages such as stability is good and with Low costs.

As shown in fig. 2, the bandpass filter according to the embodiment of the present invention may further include a first conductive pillar 261, a second conductive pillar 262, and a third conductive pillar 263; the first conductive pillar 261 is used to electrically connect the first conductor subsection 221 and the fifth conductor subsection 241; the second conductive pillar 262 is used to electrically connect the first microstrip conductor layer 21 and the sixth conductor subsection 242; the third conductive pillar 263 is used to electrically connect the second conductor subsection 222 and the seventh conductor subsection 243.

For example, as shown in fig. 2, since the first conductor subsection 221 and the fifth conductor subsection 241 are arranged in different layers, in order to ensure that the first inductance 1L can be formed by the first conductor subsection 221 and the fifth conductor subsection 241, a first conductive pillar 261 is added to the band pass filter, and the first conductive pillar 261 serves as an electrical connection medium for the first conductor subsection 221 and the fifth conductor subsection 241, so that the electrical connection between the first conductor subsection 221 and the fifth conductor subsection 241 is realized, and the first inductance 1L is ensured. Similarly, in order to ensure that the first microstrip conductor layer 21 and the sixth conductor subsection 242 may first form the second inductor 2L, the second conductive pillar 262 is added in the bandpass filter, and the second conductive pillar 262 is used as an electrical connection medium for the first microstrip conductor layer 21 and the sixth conductor subsection 242, so as to realize the electrical connection between the first microstrip conductor layer 21 and the sixth conductor subsection 242, and ensure that the second inductor 2L is obtained. Similarly, in order to ensure that the third inductor 3L can be formed first in the second conductor subsection 222 and the seventh conductor subsection 243, a third conductive pillar 263 is added to the bandpass filter, and the third conductive pillar 263 serves as an electrical connection medium for the second conductor subsection 222 and the seventh conductor subsection 243, so as to realize the electrical connection between the second conductor subsection 222 and the seventh conductor subsection 243, and ensure that the third inductor 3L is obtained. Further, by additionally arranging the first conductive column 261, the second conductive column 262 and the third conductive column 263 in the bandpass filter, the first conductive column 261, the second conductive column 262 and the third conductive column 263 can also be used as a support column of the bandpass filter, so that the stability of the bandpass filter structure is ensured.

Further, as shown in fig. 2, the input electrode 231 is electrically connected to the first conductive pillar 261, and the output electrode 232 is electrically connected to the third conductive pillar 263.

Illustratively, as shown in fig. 2 and 3, the input electrode 231 may be electrically connected to the first resonant unit 1A of the filter circuit 2, and more specifically, the input electrode 231 may be electrically connected to the first conductive pillar 261, so that the first resonant unit 1A may serve as a first-stage filter unit. The output electrode 232 may be electrically connected to the third resonant unit 3A of the filter circuit 2, and more specifically, the output electrode 232 may be electrically connected to the third conductive pillar 263, so that the third resonant unit 3A may serve as a third-stage filter unit. On this basis, the second resonance unit 2A is used as a second-stage filtering unit, so that three-stage filtering is realized in sequence, and the simple and efficient implementation mode of the three-stage filtering is ensured.

Fig. 4 is a top view of a microstrip conductor layer in a bandpass filter according to an embodiment of the present invention, further, the first conductive column 261, the second conductive column 262, and the third conductive column 263 are arranged in a straight line.

Exemplarily, the first conductive column 261, the second conductive column 262 and the third conductive column 263 are arranged in a straight line, so that the structure of the band pass filter can be ensured to be regular, and the miniaturization design of the band pass filter can be realized.

Fig. 5 is a front view of a microstrip conductor layer in a bandpass filter according to an embodiment of the present invention, and as shown in fig. 4 and fig. 5, the first conductor subsection 221 includes a plurality of first conductor segments disposed in succession, and the extending direction of any two connected first conductor segments is vertical; the second conductor subsection 222 includes a plurality of second conductor segments arranged in series, and the extension direction of any two connected second conductor segments is vertical; the first microstrip conductor layer includes a third conductor segment, and the first conductor segment and the second conductor segment are symmetrically disposed on two sides of the third conductor segment 21.

The first conductor subsection 221 and the second conductor subsection 222 are both formed by a plurality of conductor segments, any two connected conductor segments are vertically distributed, the third conductor segment extends along the same direction, the distances from the first conductor subsection 221 and the second conductor subsection 222 to the two sides of the third conductor segment are a, the distances are equal, the conductor segments are symmetrically distributed, and the specific value of a is not specifically limited in the embodiment. By arranging the first conductor subsection 221 to include a plurality of first conductor segments which are sequentially connected, and the second conductor subsection 222 to include a plurality of second conductor segments which are sequentially connected, it is ensured that the first inductor 1L, i.e., the third inductor 3L, has a large value, it is further ensured that the coupling between the first resonance unit 1A and the second resonance unit 2A is good, and the coupling between the third resonance unit 3A and the second resonance unit 2A is good.

With continued reference to fig. 1 and 2, any two conductor layers of the first microstrip conductor layer 21, the second microstrip conductor layer 22, the third microstrip conductor layer 23, the first planar conductor layer 24, and the second planar conductor layer 25 are disposed in parallel.

The filter circuits in the band-pass filter are laminated structures which are sequentially stacked, and the optimal distance between layers can be ensured by arranging the parallel laminated structures, so that the optimal coupling effect is realized.

With continued reference to fig. 1, the ground port electrodes include a first ground port electrode 331 and a second ground port electrode 332;

the first ground port electrode 331 is disposed on a first surface of the substrate 1, the second ground port electrode 332 is disposed on a second surface of the substrate 1, and the first surface and the second surface are disposed oppositely;

the input port electrode 321 is disposed on a third surface of the base 1, and the output port electrode 322 is disposed on a fourth surface of the base 1, the third surface and the fourth surface being disposed opposite to each other.

The ground port electrodes may include a first ground port electrode 331 and a second ground port electrode 332, that is, the ground port electrode has two ground port electrodes disposed on two opposite surfaces, which may achieve a better grounding effect.

Further, the input port electrode 321 and the output port electrode 322 are disposed on two opposite surfaces, and different from the surface on which the ground port electrode is disposed, the port electrode is simply disposed.

Fig. 1 is a schematic structural diagram of a band-pass filter according to an embodiment of the present invention, in which an extension length of a substrate 1 in a first direction is L1, an extension length in a second direction is L2, and an extension length in a third direction is L3;

wherein L1 is more than or equal to 1.9mm and less than or equal to 2.1mm, L2 is more than or equal to 1.2mm and less than or equal to 1.3mm, and L3 is more than or equal to 0.6mm and less than or equal to 0.7 mm; any two directions of the first direction L1, the second direction L2, and the third direction L3 are perpendicular to each other.

Wherein, the utility model provides a band pass filter, the resonance unit that has comprises resonance inductance and resonance electric capacity of novel structure, and resonance inductance and resonance electric capacity pile up the filter circuit who constitutes in proper order at the multilayer, and simple structure all reduces in L1, L2 and L3 orientation size, so the band pass filter size can be for 2.0mm 1.25mm 0.65mm, the embodiment of the utility model provides a band pass filter structure compares with traditional wave filter has simple structure, the little advantage of size.

Fig. 6 is an S-parameter curve of a band pass filter provided by an embodiment of the present invention, where a pass band range of the band pass filter is 3400MHz-3600 MHz.

In fig. 6, the abscissa represents the frequency of the filter, and the ordinate represents the attenuation of the signal of the filter. Wherein the abscissa of m1 is 3.4GHz and the abscissa of m3 is 3.6GHz, wherein the difference in the abscissas between m1 and m3 of 0.2GHz represents the passband bandwidth of the filter; the horizontal and vertical scale of m2, 3.5GHz, represents the center frequency of the filter, which is the middle frequency between the pass band frequencies of the filter; the ordinate of m1, m2, and m3 represents the insertion loss of the pass band, each of which is 1.85db or less, the insertion loss representing the loss of power occurring due to the cut-in of the filter in the transmission of a signal or power supply; the ordinate of m4 represents return loss, and refers to attenuation caused by signal reflection, which is referred to as return loss, because a signal is reflected when uneven wave impedance is encountered during transmission, increasing signal transmission loss, distorting the signal, and the like. m5 frequency is in high-end frequency 4400MHz-7000MHz, and its stop band restraines and is greater than 45dB, the embodiment of the utility model provides a band pass filter has synthesized tertiary resonance filtering structure and multilayer laminated structure, and it is little to have the insertion loss, and the stop band restraines advantages such as height.

Above is the core thought of the utility model, will combine the attached drawing in the embodiment of the utility model below, to the technical scheme in the embodiment of the utility model clearly, describe completely. Based on the embodiments in the present invention, under the premise that creative work is not done by ordinary skilled in the art, all other embodiments obtained all belong to the protection scope of the present invention.

It should be noted that the foregoing is only a preferred embodiment of the present invention and the technical principles applied. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments illustrated herein, but is capable of various obvious modifications, rearrangements, combinations and substitutions without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail with reference to the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the scope of the present invention.

Claims (10)

1. A band-pass filter is characterized by comprising a substrate, a port electrode arranged on the surface of the substrate and a filter circuit arranged in the substrate; the port electrode comprises an input port electrode, an output port electrode and a grounding port electrode;

the filter circuit comprises a first microstrip conductor layer, a second microstrip conductor layer, a third microstrip conductor layer, a first plane conductor layer and a second plane conductor layer which are sequentially arranged in a laminated manner; the first microstrip conductor layer, the second microstrip conductor layer and the second planar conductor layer are all electrically connected with the ground port electrode;

the second microstrip conductor layer comprises a first conductor subsection and a second conductor subsection, the third microstrip conductor layer comprises a third conductor subsection and a fourth conductor subsection, and the first planar conductor layer comprises a fifth conductor subsection, a sixth conductor subsection, and a seventh conductor subsection;

the filter circuit comprises a first resonance unit, a second resonance unit and a third resonance unit, and the first resonance unit, the second resonance unit and the third resonance unit are coupled in pairs; the first resonance unit comprises a first inductor and a first capacitor, the second resonance unit comprises a second inductor and a second capacitor, and the third resonance unit comprises a third inductor and a third capacitor;

the first inductor comprises the first conductor subsection and the fifth conductor subsection, and the first capacitor comprises the fifth conductor subsection and the second planar conductor layer; the second inductor comprises the first microstrip conductor layer and the sixth conductor subsection, and the second capacitor comprises the sixth conductor subsection and the second planar conductor layer; the third inductor comprises the second conductor subsection and the seventh conductor subsection, and the third capacitor comprises the seventh conductor subsection and the second planar conductor layer;

the band-pass filter also comprises an input electrode and an output electrode, wherein the input electrode is respectively and electrically connected with the filter circuit and the input port electrode, and the output electrode is respectively and electrically connected with the filter circuit and the output port electrode; the input electrode comprises the third conductor subsection and the output electrode comprises the fourth conductor subsection.

2. The bandpass filter according to claim 1, further comprising a first conductive pillar, a second conductive pillar, and a third conductive pillar;

the first conductive pillar is for electrically connecting the first conductor subsection and the fifth conductor subsection;

the second conductive pillar is for electrically connecting the first microstrip conductor layer and the sixth conductor subsection;

the third conductive pillar is for electrically connecting the second conductor subsection and the seventh conductor subsection.

3. The bandpass filter of claim 2, wherein the input electrode is electrically connected to the first conductive pillar and the output electrode is electrically connected to the third conductive pillar.

4. The bandpass filter of claim 2, wherein the first conductive post, the second conductive post, and the third conductive post are aligned in a straight line.

5. The bandpass filter according to claim 1, wherein the first conductor section comprises a plurality of first conductor segments arranged one after another, and the extension direction of any two of the first conductor segments that are connected is vertical;

the second conductor subsection comprises a plurality of second conductor segments which are sequentially connected, and the extending directions of any two connected second conductor segments are vertical;

the first microstrip conductor layer includes a third conductor section, and the first conductor section and the second conductor section are symmetrically disposed on two sides of the third conductor section.

6. The bandpass filter according to claim 1, wherein any two conductor layers of the first microstrip conductor layer, the second microstrip conductor layer, the third microstrip conductor layer, the first planar conductor layer, and the second planar conductor layer are disposed in parallel.

7. The bandpass filter according to claim 1, wherein the ground port electrode comprises a first ground port electrode and a second ground port electrode;

the first ground port electrode is arranged on a first surface of the substrate, the second ground port electrode is arranged on a second surface of the substrate, and the first surface and the second surface are oppositely arranged;

the input port electrode is arranged on a third surface of the base body, the output port electrode is arranged on a fourth surface of the base body, and the third surface and the fourth surface are oppositely arranged.

8. The bandpass filter according to claim 1, wherein the substrate has an extension length in the first direction of L1, an extension length in the second direction of L2, and an extension length in the third direction of L3;

wherein L1 is more than or equal to 1.9mm and less than or equal to 2.1mm, L2 is more than or equal to 1.2mm and less than or equal to 1.3mm, and L3 is more than or equal to 0.6mm and less than or equal to 0.7 mm;

any two directions of the first direction, the second direction and the third direction are perpendicular to each other.

9. The bandpass filter according to claim 1, wherein the passband of the bandpass filter is in the range of 3400MHz-3600 MHz.

10. The bandpass filter according to claim 1, wherein the substrate comprises a low temperature co-fired ceramic substrate.

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