CN219017891U - Band-pass filter - Google Patents

Abstract

The utility model discloses a band-pass filter, which relates to the technical field of microwaves, and comprises: the first shielding layer, the resonance coupling layer and the second shielding layer are sequentially stacked from top to bottom and are manufactured by adopting a low-temperature co-fired ceramic process; a resonant coupling layer comprising: the first coupling line, the second coupling line, four resonators and three couplers which are sequentially arranged from left to right; a coupler is arranged between every two adjacent resonators; the first coupling line is positioned above the leftmost resonator and the rightmost resonator; the second coupling line is positioned below the middle two resonators; the resonator and the coupler are both connected with a grounding port; the resonator at the leftmost end is connected with the input port; the resonator at the rightmost end is connected with the output port; the first shielding layer and the second shielding layer are both connected with the grounding port. The utility model can make the relative bandwidth of the pass band smaller than 10%, and improve the pass band performance and the stop band suppression performance.

Description

Band-pass filter

Technical Field

The utility model relates to the technical field of microwaves, in particular to a band-pass filter.

Background

With the continuous development of communication technology, wireless signals in space are more and more complex, and the requirement of frequency selectivity of hardware is also more and more high. The narrow-band-pass filter can provide excellent narrow-band signals for the radio frequency system, and has various design types and wide application range.

LTCC, low temperature co-fired ceramic, is a thick film process with high stability, high quality factor and high integration. Compared with other materials, the ceramic material has high stability and wide dielectric constant change range, and is suitable for manufacturing microwave devices.

The design methods of the common narrow-band filter are four: the first is a lumped element coupled resonator band-pass filter which is derived from a low-pass prototype, has more auxiliary design tools, simple circuits and higher three-dimensional simulation difficulty; the second type is a microstrip line type band-pass filter, which realizes a filtering function by a 1/2 wavelength resonator or a 1/4 wavelength resonator through capacitive coupling or inductive coupling; the third type is a waveguide type band-pass filter, comprising a parallel inductance waveguide coupling band-pass filter, a small-hole diaphragm coupling waveguide resonator band-pass filter, a substrate integrated waveguide filter and the like; the fourth is a stripline type bandpass filter including a cross-shaped capacitively coupled stripline filter, a comb line bandpass filter, and the like.

At present, the relative bandwidth range of the comb-shaped line band-pass filter is about 15%, and the passband performance and the stopband suppression performance are to be improved.

Disclosure of Invention

Based on the above, the embodiment of the utility model provides a band-pass filter, so that the relative bandwidth of a pass band is less than 10%, and the pass band performance and the stop band suppression performance are improved.

In order to achieve the above object, the present utility model provides the following solutions:

a bandpass filter, comprising: the first shielding layer, the resonance coupling layer and the second shielding layer are sequentially stacked from top to bottom; the first shielding layer, the resonance coupling layer and the second shielding layer are all printed circuits manufactured by adopting a low-temperature co-fired ceramic process;

the resonance coupling layer includes: the first coupling line, the second coupling line, four resonators and three couplers; the four resonators are sequentially arranged from left to right; one coupler is arranged between every two adjacent resonators; the first coupling line is positioned above the leftmost resonator and the rightmost resonator; the second coupling line is positioned below the middle two resonators; the four resonators and the three couplers are connected with a grounding port; the resonator at the leftmost end is connected with the input port; the resonator at the rightmost end is connected with the output port; the first shielding layer and the second shielding layer are connected with the grounding port;

the first coupling line is used for coupling and connecting the leftmost resonator and the rightmost resonator; the second coupling line is used for coupling and connecting the two resonators in the middle; the coupler is used for coupling and connecting two adjacent resonators.

Optionally, the band-pass filter further includes: an input layer, an output layer, and a ground layer; the input layer, the output layer and the grounding layer are all printed circuits manufactured by adopting a low-temperature co-fired ceramic process; the input layer and the output layer are arranged in bilateral symmetry;

the input layer comprises: two input wire frames which are arranged symmetrically up and down and are connected with each other; one of the input wire frames is positioned above the first shielding layer, and the other input wire frame is positioned below the second shielding layer; an input port is arranged on the input wire frame;

the output layer comprises: two output line frames which are arranged up and down symmetrically and are connected with each other; one of the output wire frames is positioned above the first shielding layer, and the other output wire frame is positioned below the second shielding layer; an output port is arranged on the output line frame;

the ground layer includes: the first grounding layer and the second grounding layer are symmetrically arranged front and back;

the first ground layer includes: two first grounding frames which are arranged symmetrically up and down and are connected with each other; one of the first grounding frames is positioned above the first shielding layer, and the other first grounding frame is positioned below the second shielding layer; the first grounding frames are respectively staggered with the input wire frames and the output wire frames; a first grounding port is arranged on the first grounding frame;

the second ground layer includes: two second grounding frames which are arranged symmetrically up and down and are connected with each other; one of the second grounding frames is positioned above the first shielding layer, and the other second grounding frame is positioned below the second shielding layer; the second grounding frames are respectively staggered with the input wire frames and the output wire frames; the second grounding frame is provided with a second grounding port; the ground port includes the first ground port and the second ground port.

Optionally, each of the four resonators includes a second resonance frame, a first resonance frame and a third resonance frame which are sequentially stacked from top to bottom; the first resonance frames are staggered with the second resonance frames and the third resonance frames;

the three couplers comprise a second coupling frame, a first coupling frame and a third coupling frame which are sequentially stacked from top to bottom; the first coupling frames are staggered with the second coupling frames and the third coupling frames; the second coupling frame of the coupler is positioned between the second resonance frames of two adjacent resonators; the first coupling frame of the coupler is positioned between the first resonance frames of two adjacent resonators; the third coupling frame of the coupler is positioned between the third resonance frames of two adjacent resonators;

the first coupling line comprises a first coupling part and a second coupling part connected with the first coupling part; the first coupling part is positioned above the second coupling frame of the leftmost resonator, and the second coupling part is positioned above the second coupling frame of the rightmost resonator;

the second coupling line comprises a third coupling part and a fourth coupling part connected with the third coupling part; the third coupling part is positioned below the third coupling frame of the middle resonator, and the fourth coupling part is positioned below the third coupling frame of the middle resonator.

Optionally, the band-pass filter includes: an input connection line and an output connection line;

the resonator at the leftmost end is connected with the input port on each input wire frame through the input connecting wire; and the resonator at the rightmost end is connected with the output port on each output wire frame through the output connecting wire.

Optionally, the band-pass filter further includes: an input tap and an output tap;

the resonator at the leftmost end is connected with the input connecting wire through the input tap; the resonator at the rightmost end is connected with the output connecting wire through the output tap.

Optionally, the first shielding layer and the second shielding layer are both defected structures.

Optionally, the input port, the output port, the first ground port, and the second ground port are all 50 ohm impedance ports.

Optionally, the line width of the first resonance frame and the third resonance frame of each resonator is 120 μm; the line width of the second resonance frame of each resonator is 100 mu m; the distance between two adjacent resonators is 620 μm.

Optionally, the line width of each coupler is 100 μm; the line spacing of the coupler from adjacent resonators is 310 μm;

the layer spacing between the first coupling part of the first coupling line and the second coupling frame of the leftmost resonator is 200 mu m; the layer spacing between the second coupling part of the first coupling line and the second coupling frame of the rightmost resonator is 200 mu m;

the layer spacing between the third coupling part of the second coupling line and the third coupling frame of the middle resonator is 250 mu m; the layer spacing between the fourth coupling part of the second coupling line and the third coupling frame of the other resonator in the middle is 250 mu m.

Optionally, the band pass filter has dimensions of 3.2mm×1.6mm×0.94mm.

Compared with the prior art, the utility model has the beneficial effects that:

the embodiment of the utility model provides a band-pass filter, which comprises the following components: the first shielding layer, the resonance coupling layer and the second shielding layer are sequentially stacked from top to bottom and are manufactured by adopting a low-temperature co-fired ceramic process; a resonant coupling layer comprising: the first coupling line, the second coupling line, four resonators and three couplers which are sequentially arranged from left to right; a coupler is arranged between every two adjacent resonators; the first coupling line is positioned above the leftmost resonator and the rightmost resonator; the second coupled line is located below the middle two resonators. According to the utility model, through reasonably arranging the coupling structures of the resonator, the coupler, the first coupling line and the second coupling line, the relative bandwidth of the passband is less than 10%, and the passband performance and the stopband inhibition performance are improved.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions of the prior art, the drawings that are needed in the embodiments will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present utility model, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a front view of a bandpass filter according to an embodiment of the utility model;

fig. 2 is a side view of a bandpass filter according to an embodiment of the utility model;

FIG. 3 is an internal view of a bandpass filter according to an embodiment of the utility model;

fig. 4 is a schematic diagram of a test curve of a bandpass filter according to an embodiment of the utility model.

Symbol description:

an input port-P1, a first ground port-P2, an output port-P3, a second ground port-P4, a first input connection line-Lin 1, a second input connection line-Lin 2, a third input connection line-Lin 3, an input tap-T1, a first output connection line-Lout 1, a second output connection line-Lout 2, a third output connection line-Lout 3, an output tap-T2, a first resonator-R1, a second resonator-R2, a third resonator-R3, a fourth resonator-R4, a first coupler-K1, a second coupler-K2, a third coupler-K3, a first shield layer-SD 1, a second shield layer-SD 2, a first coupling line-Z1, a second coupling line-U1, a first resonator frame-R11, a first resonator second resonator frame-R12, a first resonator third resonator frame-R13, a first resonator frame-R21 of the second resonator, a second resonator frame-R22 of the second resonator, a third resonator frame-R23 of the second resonator, a first resonator frame-R31 of the third resonator, a second resonator frame-R32 of the third resonator, a third resonator frame-R33 of the third resonator, a first resonator frame-R41 of the fourth resonator, a second resonator frame-R42 of the fourth resonator, a third resonator frame-R43 of the fourth resonator, a first coupling frame K11 of the first coupler, a second coupling frame K12 of the first coupler, a third coupling frame K13 of the first coupler, a first coupling frame K21 of the second coupler, a second coupling frame K22 of the second coupler, a third coupling frame K23 of the second coupler, a first coupling frame K31 of the third coupler, the second coupling frame K32 of the third coupler, the third coupling frame K33 of the third coupler.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present utility model, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In order that the above-recited objects, features and advantages of the present utility model will become more readily apparent, a more particular description of the utility model will be rendered by reference to the appended drawings and appended detailed description.

Example 1

The bandpass filter provided in the embodiment of the present utility model is a combline bandpass filter, please refer to fig. 1 and fig. 2, and the bandpass filter includes: a first shielding layer SD1, a resonance coupling layer, and a second shielding layer SD2, which are sequentially stacked from top to bottom; the first shielding layer SD1, the resonant coupling layer and the second shielding layer SD2 are all printed circuits manufactured by low temperature co-fired ceramic (LTCC) technology.

The resonance coupling layer includes: the first coupling line Z1, the second coupling line U1, four resonators and three couplers. The four resonators are a first resonator R1, a second resonator R2, a third resonator R3 and a fourth resonator R4, respectively. The three couplers are a first coupler K1, a second coupler K2 and a third coupler K3 respectively. The four resonators are sequentially arranged from left to right; one coupler is arranged between every two adjacent resonators. The first coupling line Z1 is positioned above the leftmost resonator (namely the first resonator R1) and the rightmost resonator (namely the fourth resonator R4); the second coupling line U1 is located below the middle two resonators (i.e., the second resonator R2 and the third resonator R3); the four resonators and the three couplers are connected with a grounding port; the leftmost resonator (i.e., the first resonator R1) is connected to the input port P1; the rightmost resonator (i.e., the fourth resonator R4) is connected to the output port P3; the first shielding layer SD1 and the second shielding layer SD2 are both connected to the ground port.

The first coupling line Z1 is also called a zigzag coupling line, and is used for coupling and connecting the leftmost resonator (i.e., the first resonator R1) and the rightmost resonator (i.e., the fourth resonator R4), where the coupling mode is electric coupling and may be called zigzag coupling.

The second coupling line U1 is also called a U-shaped coupling line, and is used for coupling and connecting the two resonators in the middle (i.e. the second resonator R2 and the third resonator R3), and the coupling mode is electric coupling, which may be called U-shaped coupling.

The coupler is used for coupling and connecting two adjacent resonators, and the coupling mode is magnetic coupling and can be called short-circuit branch coupling. Specifically, the first coupler K1 may adjust the magnetic coupling between the first resonator R1 and the second resonator R2; the second coupler K2 may adjust the magnetic coupling between the second resonator R2 and the third resonator R3; the third coupler K3 may adjust the magnetic coupling between the third resonator R3 and the fourth resonator R4.

In one example, still referring to fig. 1 and 2, the band-pass filter further includes: an input layer, an output layer, and a ground layer; the input layer, the output layer and the grounding layer are all printed circuits manufactured by adopting a low-temperature co-fired ceramic process; the input layer and the output layer are arranged in bilateral symmetry.

The input layer comprises: two input wire frames which are arranged symmetrically up and down and are connected with each other; one of the input wire frames is located above the first shielding layer SD1, and the other input wire frame is located below the second shielding layer SD2; the input wire frame is provided with an input port P1.

The output layer comprises: two output line frames which are arranged up and down symmetrically and are connected with each other; one of the output line frames is located above the first shielding layer SD1, and the other output line frame is located below the second shielding layer SD2; and an output port P3 is arranged on the output line frame.

The ground layer includes: the first grounding layer and the second grounding layer are arranged in a front-back symmetrical mode.

The first ground layer includes: two first grounding frames which are arranged symmetrically up and down and are connected with each other; one of the first grounding frames is located above the first shielding layer SD1, and the other first grounding frame is located below the second shielding layer SD2; the first grounding frames are respectively staggered with the input wire frames and the output wire frames; the first grounding frame is provided with a first grounding port P2.

The second ground layer includes: two second grounding frames which are arranged symmetrically up and down and are connected with each other; one of the second grounding frames is located above the first shielding layer SD1, and the other second grounding frame is located below the second shielding layer SD2; the second grounding frames are respectively staggered with the input wire frames and the output wire frames; the second grounding frame is provided with a second grounding port P4; the ground ports include the first ground port P2 and the second ground port P4.

As an alternative implementation manner, the input port P1, the first ground port P2, the output port P3, and the second ground port P4 are respectively in a symmetrical structure; the first coupling line Z1 is positioned on the upper sides of the first resonator R1 and the fourth resonator R4; the second coupling line U1 is positioned at the lower sides of the second resonator R2 and the third resonator R3; the first coupler K1 is located at the center of the first resonator R1 and the second resonator R2, the second coupler K2 is located at the center of the second resonator R2 and the third resonator R3, the third coupler K3 is located at the center of the third resonator R3 and the fourth resonator R4 and is symmetrical to the first coupler K1, and finally a laminated structure is formed.

In another example, the band pass filter includes: input connection lines and output connection lines. The resonator at the leftmost end (namely the first resonator R1) is connected with the input port P1 on each input wire frame through the input connecting wire; the rightmost resonator (i.e., the fourth resonator R4) is connected to the output port P3 on each of the output frames through the output connection line.

Wherein, the input connecting wire includes: a first input connection line Lin1, a second input connection line Lin2, and a third input connection line Lin3. The output connecting wire includes: the first output connection line Lout1, the second output connection line Lout2, and the third output connection line Lout3. The first input connecting line Lin1, the second input connecting line Lin2 and the third input connecting line Lin3 form an input signal shield; the first output connection line Lout1, the second output connection line Lout2 and the third output connection line Lout3 form an output signal shield.

As an alternative implementation manner, the band-pass filter further includes: an input tap T1 and an output tap T2. The leftmost resonator (i.e., the first resonator R1) is connected to the input connection line through the input tap T1; the rightmost resonator (i.e. the fourth resonator R4) is connected to the output connection line via the output tap T2.

In yet another example, the first shielding layer SD1 and the second shielding layer SD2 are printed inside the band-pass filter and are both defected structures.

The input port P1, the output port P3, the first ground port P2, and the second ground port P4 are all 50 ohm impedance ports. The input port P1, the output port P3, the first ground port P2 and the second ground port P4 are external electrode pins.

The band-pass filter of the embodiment aims at the problem that the relative bandwidth range of the comb-line band-pass filter is about 15%, and the coupling structure of the resonant device is improved to enable the relative bandwidth of the pass band to be smaller than 10%, and the pass band performance and the stop band suppression performance are optimized.

Example 2

The present embodiment focuses on the structures of the resonator, the coupler, the first coupling line Z1, and the second coupling line U1.

The four resonators comprise a second resonance frame, a first resonance frame and a third resonance frame which are sequentially stacked from top to bottom; the first resonance frames are staggered with the second resonance frames and the third resonance frames.

The three couplers comprise a second coupling frame, a first coupling frame and a third coupling frame which are sequentially stacked from top to bottom; the first coupling frames are staggered with the second coupling frames and the third coupling frames; the second coupling frame of the coupler is positioned between the second resonance frames of two adjacent resonators; the first coupling frame of the coupler is positioned between the first resonance frames of two adjacent resonators; the third coupling frame of the coupler is positioned between the third resonance frames of two adjacent resonators.

The first coupling line Z1 comprises a first coupling part and a second coupling part connected with the first coupling part; the first coupling part is positioned above the second coupling frame of the leftmost resonator (namely, the first resonator R1), and the second coupling part is positioned above the second coupling frame of the rightmost resonator (namely, the fourth resonator R4).

The second coupling line U1 comprises a third coupling part and a fourth coupling part connected with the third coupling part; the third coupling part is positioned below the third coupling frame of the middle resonator, and the fourth coupling part is positioned below the third coupling frame of the middle resonator.

Specifically, referring to fig. 3, the first resonator R1 has three layers, the second resonance frame R12 in the first layer and the third resonance frame R13 in the third layer are connected to the second ground port P4, and the first resonance frame R11 in the second layer is connected to the first ground port P2; the first resonance frame R11 in the second layer is connected to the input tap T1, and the second resonance frame R12 in the first layer and the third resonance frame R13 in the third layer are connected to the first resonance frame R11 in the second layer by coupling.

The second resonator R2 comprises three layers, wherein a second resonance frame R22 in the first layer and a third resonance frame R23 in the third layer are connected with a second grounding port P4, and a first resonance frame R21 in the second layer is connected with a first grounding port P2; the second resonance frame R22 in the first layer and the third resonance frame R23 in the third layer are connected to the first resonance frame R21 in the second layer by coupling.

The third resonator R3 comprises three layers, wherein a second resonance frame R32 in the first layer and a third resonance frame R33 in the third layer are connected with a second grounding port P4, and a first resonance frame R31 in the second layer is connected with a first grounding port P2; the second resonance frame R32 in the first layer and the third resonance frame R33 in the third layer are connected to the first resonance frame R31 in the second layer by coupling.

The fourth resonator R4 has three layers, the second resonance frame R42 in the first layer and the third resonance frame R43 in the third layer are connected to the second ground port P4, and the first resonance frame R41 in the second layer is connected to the first ground port P2; the first resonance frame R41 in the second layer is connected to the output tap T2, and the second resonance frame R42 in the first layer and the third resonance frame R43 in the third layer are connected to the first resonance frame R41 in the second layer by coupling.

The first coupler K1 has three layers, the second coupling frame K12 in the first layer and the third coupling frame K13 in the third layer are connected to the second ground port P4, and the first coupling frame K11 in the second layer is connected to the first ground port P2. The second coupler K2 has three layers, the second coupling frame K22 in the first layer and the third coupling frame K23 in the third layer are connected to the second ground port P4, and the first coupling frame K21 in the second layer is connected to the first ground port P2. The third coupler K3 has three layers, the second coupling frame K32 in the first layer and the third coupling frame K33 in the third layer are connected to the second ground port P4, and the first coupling frame K31 in the second layer is connected to the first ground port P2.

The band-pass filter of this embodiment has 7 printed circuit layers, which are respectively a three-layer printed circuit layer composed of a resonator and a coupler, a one-layer printed circuit layer composed of a first coupling line, a one-layer printed circuit layer composed of a second coupling line, and two-layer printed circuit layers composed of a first shielding layer and a second shielding layer. The input port P1 of the band-pass filter is respectively connected with a first input connecting line Lin1, a second input connecting line Lin2 and a third input connecting line Lin 3; the first grounding port P2 is respectively connected with the first layer and the third layer of the first resonator R1, the second resonator R2, the third resonator R3, the fourth resonator R4, the first coupler K1, the second coupler K2 and the third coupler K3; the output port P3 is respectively connected with the first output connecting line Lout1, the second output connecting line Lout2 and the third output connecting line Lout 3; the second grounding port P4 is respectively connected with the second layers of the first resonator R1, the second resonator R2, the third resonator R3, the fourth resonator R4, the first coupler K1, the second coupler K2 and the third coupler K3; the first shield layer SD1 and the second shield layer SD2 are connected to the first ground port P2 and the second ground port P4, respectively.

The first coupling line Z1 connects the first resonator R1 and the fourth resonator R4 through electric coupling, and the second coupling line U1 connects the second resonator R2 and the third resonator R3 through electric coupling.

The bandpass filter of this embodiment includes four sets of eighth wavelength resonators, three sets of frequency modulation branches, two coupling branches and two metal shielding layers. The resonator consists of three layers of short circuit branches, and a feed end is connected with an open-circuit port of the resonator by adopting a strip line. The band-pass filter controls the bandwidth of a passband and suppresses higher harmonics through the position and the size of the frequency modulation branches, meanwhile, weak electric coupling is introduced between source loads, transmission zero points are generated near the passband, and better frequency selectivity is achieved. The method is realized by adopting the LTCC technology, has the advantages of small element volume, high temperature resistance of the element, low processing cost, good working stability, good material consistency, good environmental protection and the like, and can be widely applied to the fields of base stations in microwave bands, internet of things and the like.

Example 3

This embodiment focuses on the dimensions of the various parts in the band-pass filter.

In one example, the line width and line spacing of the inner conductors (i.e., all conductor lines inside the device) are not less than 50 μm, and the line widths of the first and third resonance frames of each of the resonators are preferably 120 μm; the line width of the second resonance frame of each resonator is preferably 100 μm; the spacing between two adjacent resonators is preferably 620 μm. The line width of each coupler is preferably 100 μm; the line spacing of the coupler from adjacent resonators is preferably 310 μm.

In another example, the inter-layer distance of the inner conductor (i.e., all conductor lines inside the device) is not less than 15 μm, the inter-layer distance between the resonator and the coupler is preferably 40 μm (i.e., the inter-layer distance between the three layers of the resonator is 40 μm, the inter-layer distance between the three layers of the coupler is also 40 μm), and the inter-layer distance between the first coupling portion of the first coupling line and the second coupling frame of the leftmost resonator (i.e., the first resonator) is preferably 200 μm; the layer spacing between the second coupling portion of the first coupling line and the second coupling frame of the rightmost resonator (i.e., the fourth resonator) is preferably 200 μm. The layer spacing between the third coupling part of the second coupling line and the third coupling frame of the middle resonator is preferably 250 μm; the layer spacing of the fourth coupling portion of the second coupled line from the third coupling frame of the other resonator in between is preferably 250 μm.

In yet another example, the bandpass filter employs a 7-layer printed circuit structure based on LTCC technology, which may be 3.2mm by 1.6mm by 0.94mm in size.

Fig. 4 shows a test curve of a band-pass filter, with frequency on the abscissa and loss on the ordinate. As can be seen from the test curve, the band-pass filter has a working frequency range of 7.1 GHz-7.5 GHz, a relative bandwidth of 5.5%, an insertion loss of better than-1.65 dB, a return loss of an input port of better than-19 dB, an attenuation of the upper stop band range DC-12 GHz of less than-30 dB, and an attenuation of the lower stop band range 8.2 GHz-17.5 GHz of less than-30 dB. Therefore, the band-pass filter of the embodiment can enable the relative bandwidth of the pass band to be smaller than 10%, and improves the pass band performance and the stop band suppression performance.

In addition, the band-pass filter of the embodiment adopts a comb line structure for design; the band-pass filter can be combined in various ways to realize more preferable schemes; the band-pass filter innovatively introduces short-circuit branches (four resonators and three couplers) to tune magnetic coupling among the resonators, so that the application range of the vanity line filter is effectively widened.

The band-pass filter of the embodiment adopts symmetrical design, has simple and symmetrical circuit structure and is convenient for design and development; the microwave device manufactured by utilizing the LTCC process has good high-temperature resistance, can bear larger current, can manufacture dozens of layers of substrates, and is embedded with the passive device, so that the interference of other assembly elements is reduced, and the integration level is improved; on the premise of realizing narrow-band frequency selectivity, the device has the characteristics of small size, simple structure, good stability, high reliability, high temperature resistance and good material consistency; adopting a shielding layer with a defect ground structure to inhibit higher harmonics of signals; the circuit structure is simple, and the band-pass filter with various narrow-band frequency and stop band requirements can be realized by adjusting the combination of the resonator and the coupler.

In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.

The principles and embodiments of the present utility model have been described herein with reference to specific examples, the description of which is intended only to assist in understanding the core concept of the utility model; also, it is within the scope of the present utility model to be modified by those of ordinary skill in the art in light of the present teachings. In view of the foregoing, this description should not be construed as limiting the utility model.

Claims (10)

1. A bandpass filter, comprising: the first shielding layer, the resonance coupling layer and the second shielding layer are sequentially stacked from top to bottom; the first shielding layer, the resonance coupling layer and the second shielding layer are all printed circuits manufactured by adopting a low-temperature co-fired ceramic process;

the resonance coupling layer includes: the first coupling line, the second coupling line, four resonators and three couplers; the four resonators are sequentially arranged from left to right; one coupler is arranged between every two adjacent resonators; the first coupling line is positioned above the leftmost resonator and the rightmost resonator; the second coupling line is positioned below the middle two resonators; the four resonators and the three couplers are connected with a grounding port; the resonator at the leftmost end is connected with the input port; the resonator at the rightmost end is connected with the output port; the first shielding layer and the second shielding layer are connected with the grounding port;

the first coupling line is used for coupling and connecting the leftmost resonator and the rightmost resonator; the second coupling line is used for coupling and connecting the two resonators in the middle; the coupler is used for coupling and connecting two adjacent resonators.

2. A bandpass filter according to claim 1, further comprising: an input layer, an output layer, and a ground layer; the input layer, the output layer and the grounding layer are all printed circuits manufactured by adopting a low-temperature co-fired ceramic process; the input layer and the output layer are arranged in bilateral symmetry;

the input layer comprises: two input wire frames which are arranged symmetrically up and down and are connected with each other; one of the input wire frames is positioned above the first shielding layer, and the other input wire frame is positioned below the second shielding layer; an input port is arranged on the input wire frame;

the output layer comprises: two output line frames which are arranged up and down symmetrically and are connected with each other; one of the output wire frames is positioned above the first shielding layer, and the other output wire frame is positioned below the second shielding layer; an output port is arranged on the output line frame;

the ground layer includes: the first grounding layer and the second grounding layer are symmetrically arranged front and back;

the first ground layer includes: two first grounding frames which are arranged symmetrically up and down and are connected with each other; one of the first grounding frames is positioned above the first shielding layer, and the other first grounding frame is positioned below the second shielding layer; the first grounding frames are respectively staggered with the input wire frames and the output wire frames; a first grounding port is arranged on the first grounding frame;

the second ground layer includes: two second grounding frames which are arranged symmetrically up and down and are connected with each other; one of the second grounding frames is positioned above the first shielding layer, and the other second grounding frame is positioned below the second shielding layer; the second grounding frames are respectively staggered with the input wire frames and the output wire frames; the second grounding frame is provided with a second grounding port; the ground port includes the first ground port and the second ground port.

3. A bandpass filter according to claim 1, wherein each of the four resonators includes a second resonator frame, a first resonator frame, and a third resonator frame, which are stacked in this order from top to bottom; the first resonance frames are staggered with the second resonance frames and the third resonance frames;

the three couplers comprise a second coupling frame, a first coupling frame and a third coupling frame which are sequentially stacked from top to bottom; the first coupling frames are staggered with the second coupling frames and the third coupling frames; the second coupling frame of the coupler is positioned between the second resonance frames of two adjacent resonators; the first coupling frame of the coupler is positioned between the first resonance frames of two adjacent resonators; the third coupling frame of the coupler is positioned between the third resonance frames of two adjacent resonators;

the first coupling line comprises a first coupling part and a second coupling part connected with the first coupling part; the first coupling part is positioned above the second coupling frame of the leftmost resonator, and the second coupling part is positioned above the second coupling frame of the rightmost resonator;

the second coupling line comprises a third coupling part and a fourth coupling part connected with the third coupling part; the third coupling part is positioned below the third coupling frame of the middle resonator, and the fourth coupling part is positioned below the third coupling frame of the middle resonator.

4. A bandpass filter according to claim 2, characterized in that it comprises: an input connection line and an output connection line;

the resonator at the leftmost end is connected with the input port on each input wire frame through the input connecting wire; and the resonator at the rightmost end is connected with the output port on each output wire frame through the output connecting wire.

5. The bandpass filter according to claim 4, further comprising: an input tap and an output tap;

the resonator at the leftmost end is connected with the input connecting wire through the input tap; the resonator at the rightmost end is connected with the output connecting wire through the output tap.

6. A bandpass filter according to claim 1, wherein the first shielding layer and the second shielding layer are each structured as defects.

7. A bandpass filter according to claim 2, wherein the input port, the output port, the first ground port and the second ground port are each 50 ohm impedance ports.

8. A bandpass filter according to claim 3, wherein the first and third resonator frames of each resonator have a linewidth of 120 μm; the line width of the second resonance frame of each resonator is 100 mu m; the distance between two adjacent resonators is 620 μm.

9. A bandpass filter according to claim 8, wherein each of the couplers has a linewidth of 100 μm; the line spacing of the coupler from adjacent resonators is 310 μm;

the layer spacing between the first coupling part of the first coupling line and the second coupling frame of the leftmost resonator is 200 mu m; the layer spacing between the second coupling part of the first coupling line and the second coupling frame of the rightmost resonator is 200 mu m;

the layer spacing between the third coupling part of the second coupling line and the third coupling frame of the middle resonator is 250 mu m; the layer spacing between the fourth coupling part of the second coupling line and the third coupling frame of the other resonator in the middle is 250 mu m.

10. A bandpass filter according to claim 9, characterized in that the bandpass filter has dimensions of 3.2mm x 1.6mm x 0.94mm.

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