Bandwidth-adjustable high-selectivity filter

Abstract

The invention discloses a bandwidth-adjustable high-selectivity filter, and relates to the field of filters, the bandwidth-adjustable high-selectivity filter comprises a ceramic dielectric body, a circuit layer in the ceramic dielectric body and an outer electrode on the outer side wall of the ceramic dielectric body, and the outer electrode comprises an input port, an output port and a grounding port; the circuit layer comprises a multi-order microstrip line coupling band-pass filter and a low-pass filter. The problem that the high Q value, the wide stop band and the high suppression characteristic of the filter are difficult to realize in the volume as small as possible in the prior art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of filter, in particular to a bandwidth adjustable high selectivity filter. BACKGROUND

[0002] The prior art currently adopts LTCC technology and selects high dielectric ceramic material as the base body to realize miniaturization. The filter adopts a five-order resonant structure of semi-lumped and semi-transmission line, and introduces cross coupling to form a transmission zero point at a specific frequency point, thereby enhancing the out-of-band suppression capability. The coil part adopts a three-layer repeated structure design, which effectively improves the Q value of the transmission line, greatly reduces the product insertion loss, and has the characteristics of low loss and high reliability. However, the common problem of the filter realized by using these methods is that the structure is complex, or the volume is large, and it is not convenient to integrate with other compact mobile communication terminals. The quality factor of the filter is expressed by the ratio of the center frequency F of the filter to the -3dB bandwidth B, that is, Q=F / B, which describes the ability of the filter to separate adjacent frequency components in the signal. The larger the quality factor Q is, the higher the resolution capability of the filter is. The methods for improving the quality factor of the filter in the prior art mainly include generating a zero point through multipath effect, expanding the stop band by using a step impedance resonant structure, generating a zero point by using a quarter wavelength transmission inversion, and generating a zero point by using a hybrid coupling structure. Therefore, how to realize high Q value, wide stop band and high suppression characteristics of the filter in the smallest possible volume is the current research hotspot and difficulty. SUMMARY

[0003] In view of the above problems in the prior art, the present application provides a bandwidth adjustable high selectivity filter, which solves the problem that the prior art is difficult to realize high Q value, wide stop band and high suppression characteristics of the filter in the smallest possible volume.

[0004] In order to achieve the above application purpose, the technical scheme adopted by the present application is as follows: a bandwidth adjustable high selectivity filter, comprising a ceramic dielectric body, a circuit layer in the ceramic dielectric body and an external electrode on the outer sidewall of the ceramic dielectric body, the external electrode comprising an input port, an output port and a ground port; The circuit layer comprises a multi-order microstrip line coupled bandpass filter and a low-pass filter. The multi-order microstrip line coupled bandpass filter comprises a first equivalent coupling microstrip line CL1, a second equivalent coupling microstrip line CL2, a third equivalent coupling microstrip line CL3, a fourth equivalent coupling microstrip line CL4, a first equivalent capacitor C1, a second equivalent capacitor C2, a third equivalent capacitor C3, a fifth equivalent capacitor C5, a sixth equivalent capacitor C6 and a seventh equivalent capacitor C7. The low-pass filter comprises a fifth equivalent coupling microstrip line CL5, a sixth equivalent coupling microstrip line CL6, a seventh equivalent coupling microstrip line CL7, an eighth equivalent coupling microstrip line CL8, an eighth equivalent capacitor C8 and a ninth equivalent capacitor C9. One end of the eighth equivalent capacitor C8 is connected with one end of the first equivalent coupling microstrip line CL1 and one end of the fifth equivalent coupling microstrip line CL5 respectively, and the other end thereof is connected with one end of the second equivalent coupling microstrip line CL2 and one end of the sixth equivalent coupling microstrip line CL6 respectively, the other end of the fifth equivalent coupling microstrip line CL5 and the other end of the sixth equivalent coupling microstrip line CL6 are grounded, the other end of the first equivalent coupling microstrip line CL1 is connected with the input port, one end of the first equivalent capacitor C1 and one end of the second equivalent capacitor C2 respectively, the other end of the second equivalent coupling microstrip line CL2 is connected with the other end of the second equivalent capacitor C2, one end of the third equivalent capacitor C3 and one end of the fifth equivalent capacitor C5 respectively; one end of the ninth equivalent capacitor C9 is connected with one end of the seventh equivalent coupling microstrip line CL7 and one end of the third equivalent coupling microstrip line CL3 respectively, and the other end thereof is connected with one end of the eighth equivalent coupling microstrip line CL8 and one end of the fourth equivalent coupling microstrip line CL4 respectively, the other end of the seventh equivalent coupling microstrip line CL7 and the other end of the eighth equivalent coupling microstrip line CL8 are grounded, the other end of the third equivalent coupling microstrip line CL3 is connected with one end of the fifth equivalent capacitor C5 and one end of the sixth equivalent capacitor C6 respectively, the other end of the fourth equivalent coupling microstrip line CL4 is connected with the output port, the other end of the sixth equivalent capacitor C6 and one end of the seventh equivalent capacitor C7 respectively, the other end of the first equivalent capacitor C1, the other end of the third equivalent capacitor C3, the other end of the fifth equivalent capacitor C5 and the other end of the seventh equivalent capacitor C7 are grounded.

[0005] Further, the circuit layer comprises: The first circuit layer comprises a first electrode plate P1, a second electrode plate P2, a third electrode plate P3, a fourth electrode plate P4, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a fifth via hole H5, a sixth via hole H6, a seventh via hole H7 and an eighth via hole H8; The second circuit layer comprises a fifth electrode plate P5, a sixth electrode plate P6, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a sixth via hole H6 and a seventh via hole H7; The third circuit layer comprises a seventh electrode plate P7, an eighth electrode plate P8, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a ninth via hole H9 and a tenth via hole H10; The fourth circuit layer includes a ninth electrode plate P9, a tenth electrode plate P10, an eleventh electrode plate P11, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a ninth via hole H9, a tenth via hole H10, an eleventh via hole H11 and a twelfth via hole H12. The fifth circuit layer includes a twelfth electrode plate P12, a thirteenth electrode plate P13, a fourteenth electrode plate P14, a ninth via hole H9, a tenth via hole H10, an eleventh via hole H11 and a twelfth via hole H12. The sixth circuit layer includes a fifteenth electrode plate P15 and a via hole group H111. The seventh circuit layer includes a sixteenth electrode plate P16, an input port and an output port, and the sixteenth electrode plate P16 serves as the ground port.

[0006] Further, the first electrode plate P1, the fifth electrode plate P5 and the twelfth electrode plate P12 are sequentially connected in a head-to-tail manner through the first via hole H1 and the fifth via hole H5, and together form a first equivalent coupled microstrip line CL1. The second electrode plate P2, the seventh electrode plate P7 and the thirteenth electrode plate P13 are sequentially connected in a head-to-tail manner through the second via hole H2 and the sixth via hole H6, and together form a second equivalent coupled microstrip line CL2. The third electrode plate P3, the eighth electrode plate P8 and the thirteenth electrode plate P13 are sequentially connected in a head-to-tail manner through the third via hole H3 and the seventh via hole H7, and together form a third equivalent coupled microstrip line CL3. The fourth electrode plate P4, the sixth electrode plate P6 and the fourteenth electrode plate P14 are sequentially connected in a head-to-tail manner through the fourth via hole H4 and the eighth via hole H8, and together form a fourth equivalent coupled microstrip line CL4. The fifth electrode plate P5 and the fifteenth electrode plate P15 are sequentially connected in a head-to-tail manner through the fifth via hole H5, and together form a fifth equivalent coupled microstrip line CL5. The seventh electrode plate P7 and the fifteenth electrode plate P15 are sequentially connected in a head-to-tail manner through the sixth via hole H6, and together form a sixth equivalent coupled microstrip line CL6. The eighth electrode plate P8 and the fifteenth electrode plate P15 are sequentially connected in a head-to-tail manner through the twelfth via hole H12, and together form a seventh equivalent coupled microstrip line CL7. The sixth electrode plate P6 and the fifteenth electrode plate P15 are sequentially connected in a head-to-tail manner through the tenth via hole H10, and together form an eighth equivalent coupled microstrip line CL8. The twelfth electrode plate P12 and the fifteenth electrode plate P15 are coupled through interlayer coupling, and together form a first equivalent capacitor C1. The ninth electrode plate P9, the twelfth electrode plate P12 and the thirteenth electrode plate P13 are coupled through interlayer coupling, and together form a second equivalent capacitor C2. The thirteenth electrode plate P13 and the fifteenth electrode plate P15 are coupled through layers and jointly form a third equivalent capacitor C3 and a fifth equivalent capacitor C5; The tenth electrode plate P10, the thirteenth electrode plate P13 and the fourteenth electrode plate P14 are coupled through layers and jointly form a sixth equivalent capacitor C6; The fourteenth electrode plate P14 and the fifteenth electrode plate P15 are coupled through layers and jointly form a seventh equivalent capacitor C7; The fifth electrode plate P5 and the seventh electrode plate P7 are coupled through layers and jointly form an eighth equivalent capacitor C8; The sixth electrode plate P6 and the eighth electrode plate P8 are coupled through layers and jointly form a ninth equivalent capacitor C9.

[0007] Further, the fifteenth electrode plate P15 is a large-area ground layer connected with a ground port on an external electrode through a via group H111.

[0008] Further, the thickness of the first circuit layer to the top layer of the high-selectivity filter is 150 um; The thickness of the second circuit layer to the first circuit layer is 695 um; The thickness of the third circuit layer to the second circuit layer is 25 um; The thickness of the fourth circuit layer to the third circuit layer is 559 um; The thickness of the fifth circuit layer to the fourth circuit layer is 52 um; The thickness of the sixth circuit layer to the fifth circuit layer is 83 um; The thickness of the seventh circuit layer to the sixth circuit layer is 83 um.

[0009] Further, the manufacturing process of the high-selectivity filter includes: manufacturing based on a multilayer printed circuit board process, manufacturing based on a low-temperature co-fired ceramic technology, manufacturing based on an IPD process or manufacturing based on a CMOS semiconductor process; The inner-buried metal material used in the circuit layer is copper or palladium silver.

[0010] Further, the size of the ceramic dielectric body is 3.2 mm x 2.5 mm x 1.5 mm.

[0011] The bandwidth-adjustable high-selectivity filter provided by the application can realize the adjustment of the resonant mode and the coupling strength of the resonator by loading adjustable branches on the multi-mode resonator, and can realize the transmission and isolation characteristics of the filter channel of the bandwidth-adjustable function filter by using the length adjustment characteristics of the two-section coupled lines. Compared with the traditional band-pass filter, the technical scheme of the application has the following advantages: (1) Bandwidth adjustment precision flexible. The filter adjusts the resonance mode and coupling strength through the adjustable branch, and optimizes the length of the two-section coupled line, which can flexibly adjust the resonance frequency spacing of the multi-mode resonator by changing the parameters of the loaded components, and further precisely control the passband width by optimizing the length of the coupled line, which can adapt to the diversified demand for bandwidth in different scenarios.

[0012] (2) High frequency utilization efficiency. Relying on the characteristics of multi-mode resonator "simultaneous excitation of multiple resonance frequencies", without additional increase of resonator number, multi-frequency response can be realized, which improves the utilization efficiency of frequency resources in limited circuit space, especially suitable for high integration requirement of radio frequency front-end design.

[0013] (3) Adapt to batch production and integrated application. Based on microstrip line process design, it has the characteristics of planar structure, which is easy to integrate with other circuits, and can adapt to the batch production process of printed circuit board (PCB), reduce the cost of large-scale application, and its structure design can guarantee the performance stability in the adjustment process, meet the industrial production and practical application requirements of mobile phones, base stations and other radio frequency equipment.

[0014] (4) High Q value characteristics improve system anti-interference ability. Since high Q value filter can filter out interference signals in advance, it can reduce the pressure of subsequent amplification, demodulation and other circuit processing of interference signals, without additional design of complex anti-interference module, thus simplifying the overall circuit structure of the system, reducing hardware cost and power consumption, especially suitable for small devices (such as mobile phone radio frequency front-end, portable detection instrument). High Q value filter can stably realize the filtering demand of high frequency signal with its precise frequency selectivity and low loss characteristics, and meet the strict requirements of high precision communication and detection system for signal purity. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 Bandwidth adjustable high selectivity filter appearance schematic diagram.

[0016] Figure 2 Bandwidth adjustable high selectivity filter internal structure schematic diagram.

[0017] Figure 3 Equivalent schematic diagram of bandwidth adjustable high selectivity filter.

[0018] Figure 4 First circuit layer schematic diagram.

[0019] Figure 5 Second circuit layer schematic diagram.

[0020] Figure 6 Third circuit layer schematic diagram.

[0021] Figure 7 This is a schematic diagram of the fourth circuit layer.

[0022] Figure 8 This is a schematic diagram of the fifth circuit layer.

[0023] Figure 9 This is a schematic diagram of the sixth circuit layer.

[0024] Figure 10 This is a schematic diagram of the seventh circuit layer.

[0025] Figure 11 The transmission characteristic response curve of a high selectivity filter with adjustable bandwidth.

[0026] Wherein: 1. Ceramic dielectric; 2. Input port; 3. Output port; 4. Grounding port; 5. Identification symbol. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0028] like Figure 1 As shown, a high selectivity filter with adjustable bandwidth includes a ceramic dielectric 1, a circuit layer inside the ceramic dielectric 1, and an external electrode on the outer wall of the ceramic dielectric 1. The external electrode includes an input port 2, an output port 3, and a ground port 4. The identifier 5 on the top of the high-selectivity filter is used to identify the relative positions of the ports. Identifier 5 is located on the opposite side of the ground port 4, and the input port 2 and output port 3 are located on the opposite side.

[0029] The multilayer circuit of the high selectivity filter is built into a 3.2mm×2.5mm×1.5mm ceramic dielectric body 1 and sintered at a temperature of 895℃±10℃.

[0030] like Figure 2 As shown, the circuit layer includes a multi-order microstrip line coupled bandpass filter and a low-pass filter; The multi-order microstrip line coupled bandpass filter includes a first equivalent coupled microstrip line CL1, a second equivalent coupled microstrip line CL2, a third equivalent coupled microstrip line CL3, a fourth equivalent coupled microstrip line CL4, a first equivalent capacitor C1, a second equivalent capacitor C2, a third equivalent capacitor C3, a fifth equivalent capacitor C5, a sixth equivalent capacitor C6, and a seventh equivalent capacitor C7. The low-pass filter includes a fifth equivalent coupled microstrip line CL5, a sixth equivalent coupled microstrip line CL6, a seventh equivalent coupled microstrip line CL7, an eighth equivalent coupled microstrip line CL8, an eighth equivalent capacitor C8, and a ninth equivalent capacitor C9. like Figure 3As shown, one end of the eighth equivalent capacitor C8 is connected with one end of the first equivalent coupling microstrip line CL1 and one end of the fifth equivalent coupling microstrip line CL5 respectively, and the other end is connected with one end of the second equivalent coupling microstrip line CL2 and one end of the sixth equivalent coupling microstrip line CL6 respectively, the other end of the fifth equivalent coupling microstrip line CL5 and the other end of the sixth equivalent coupling microstrip line CL6 are grounded, the other end of the first equivalent coupling microstrip line CL1 is connected with the input port 2, one end of the first equivalent capacitor C1 and one end of the second equivalent capacitor C2 respectively, the other end of the second equivalent coupling microstrip line CL2 is connected with the other end of the second equivalent capacitor C2, one end of the third equivalent capacitor C3 and one end of the fifth equivalent capacitor C5 respectively; one end of the ninth equivalent capacitor C9 is connected with one end of the seventh equivalent coupling microstrip line CL7 and one end of the third equivalent coupling microstrip line CL3 respectively, and the other end is connected with one end of the eighth equivalent coupling microstrip line CL8 and one end of the fourth equivalent coupling microstrip line CL4 respectively, the other end of the seventh equivalent coupling microstrip line CL7 and the other end of the eighth equivalent coupling microstrip line CL8 are grounded, the other end of the third equivalent coupling microstrip line CL3 is connected with one end of the fifth equivalent capacitor C5 and one end of the sixth equivalent capacitor C6 respectively, the other end of the fourth equivalent coupling microstrip line CL4 is connected with the output port 3, the other end of the sixth equivalent capacitor C6 and one end of the seventh equivalent capacitor C7 respectively, the other end of the first equivalent capacitor C1, the other end of the third equivalent capacitor C3, the other end of the fifth equivalent capacitor C5 and the other end of the seventh equivalent capacitor C7 are grounded.

[0031] The circuit layer comprises: Figure 4 For the first circuit layer: the first circuit layer comprises a first electrode plate P1, a second electrode plate P2, a third electrode plate P3, a fourth electrode plate P4, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a fifth via hole H5, a sixth via hole H6, a seventh via hole H7 and an eighth via hole H8; Figure 5 For the second circuit layer: the second circuit layer comprises a fifth electrode plate P5, a sixth electrode plate P6, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a sixth via hole H6 and a seventh via hole H7; Figure 6 For the third circuit layer: the third circuit layer comprises a seventh electrode plate P7, an eighth electrode plate P8, a first via hole H1, a second via hole H2, a third via hole H3, a fourth via hole H4, a ninth via hole H9 and a tenth via hole H10; Figure 7The fourth circuit layer includes the ninth electrode plate P9, the tenth electrode plate P10, the eleventh electrode plate P11, the first via hole H1, the second via hole H2, the third via hole H3, the fourth via hole H4, the ninth via hole H9, the tenth via hole H10, the eleventh via hole H11 and the twelfth via hole H12; Figure 8 The fifth circuit layer includes the twelfth electrode plate P12, the thirteenth electrode plate P13, the fourteenth electrode plate P14, the ninth via hole H9, the tenth via hole H10, the eleventh via hole H11 and the twelfth via hole H12; Figure 9 The sixth circuit layer includes the fifteenth electrode plate P15 and the via hole group H111; Figure 10 The seventh circuit layer includes the sixteenth electrode plate P16, the input port 2 and the output port 3, and the sixteenth electrode plate P16 serves as the ground port 4.

[0032] The first electrode plate P1, the fifth electrode plate P5 and the twelfth electrode plate P12 are sequentially connected through the first via hole H1 and the fifth via hole H5, and together constitute a first equivalent coupled microstrip line CL1; The second electrode plate P2, the seventh electrode plate P7 and the thirteenth electrode plate P13 are sequentially connected through the second via hole H2 and the sixth via hole H6, and together constitute a second equivalent coupled microstrip line CL2; The third electrode plate P3, the eighth electrode plate P8 and the thirteenth electrode plate P13 are sequentially connected through the third via hole H3 and the seventh via hole H7, and together constitute a third equivalent coupled microstrip line CL3; The fourth electrode plate P4, the sixth electrode plate P6 and the fourteenth electrode plate P14 are sequentially connected through the fourth via hole H4 and the eighth via hole H8, and together constitute a fourth equivalent coupled microstrip line CL4; The fifth electrode plate P5 and the fifteenth electrode plate P15 are sequentially connected through the fifth via hole H5, and together constitute a fifth equivalent coupled microstrip line CL5; The seventh electrode plate P7 and the fifteenth electrode plate P15 are sequentially connected through the sixth via hole H6, and together constitute a sixth equivalent coupled microstrip line CL6; The eighth electrode plate P8 and the fifteenth electrode plate P15 are sequentially connected through the twelfth via hole H12, and together constitute a seventh equivalent coupled microstrip line CL7; The sixth electrode plate P6 and the fifteenth electrode plate P15 are sequentially connected through the tenth via hole H10, and together constitute an eighth equivalent coupled microstrip line CL8; The twelfth electrode plate P12 and the fifteenth electrode plate P15 are coupled through the interlayer, and together constitute a first equivalent capacitor C1; The ninth electrode plate P9, the twelfth electrode plate P12 and the thirteenth electrode plate P13 are coupled through layers and jointly constitute a second equivalent capacitor C2; The thirteenth electrode plate P13 and the fifteenth electrode plate P15 are coupled through layers and jointly constitute a third equivalent capacitor C3 and a fifth equivalent capacitor C5; The tenth electrode plate P10, the thirteenth electrode plate P13 and the fourteenth electrode plate P14 are coupled through layers and jointly constitute a sixth equivalent capacitor C6; The fourteenth electrode plate P14 and the fifteenth electrode plate P15 are coupled through layers and jointly constitute a seventh equivalent capacitor C7; The fifth electrode plate P5 and the seventh electrode plate P7 are coupled through layers and jointly constitute an eighth equivalent capacitor C8; The sixth electrode plate P6 and the eighth electrode plate P8 are coupled through layers and jointly constitute a ninth equivalent capacitor C9.

[0033] The fifteenth electrode plate P15 is a large-area ground layer and is connected with a ground port 4 on an external electrode via a via group H111.

[0034] The band-pass filter provided by the application adjusts the bandwidth by changing the lengths of two series of coupling lines, adopts low-temperature co-fired ceramic technology (LTCC), embeds two series of four resonant units and nine equivalent capacitors which constitute the filter into seven conductor layers in a ceramic body, and has microwave characteristics of high Q value and wide stop band. By reasonably selecting the equivalent component values of the resonant units of the filter and optimizing the coupling relationship of the equivalent components in the vertical space, transmission zero points can be introduced at both ends close to the pass band to realize a high rectangular coefficient, and good suppression effect can be achieved in a wide stop band range.

[0035] The thickness of the first circuit layer to the top layer of the high-selectivity filter is 150 um; The thickness of the second circuit layer to the first circuit layer is 695 um; The thickness of the third circuit layer to the second circuit layer is 25 um; The thickness of the fourth circuit layer to the third circuit layer is 559 um; The thickness of the fifth circuit layer to the fourth circuit layer is 52 um; The thickness of the sixth circuit layer to the fifth circuit layer is 83 um; The thickness of the seventh circuit layer to the sixth circuit layer is 83 um.

[0036] The manufacturing process of the high-selectivity filter comprises: manufacturing based on a multilayer printed circuit board process, manufacturing based on low-temperature co-fired ceramic technology, manufacturing based on an IPD process or manufacturing based on a CMOS semiconductor process; The circuit layer can use high-conductivity metal materials, such as silver and copper, as the conductor material, which is beneficial to improve the quality factor of the circuit system. For example, palladium silver can be used as the embedded metal material, which will not be oxidized during the sintering process, and can not need plating protection.

[0037] The dielectric constant of the ceramic body material used by the bandwidth-adjustable high-selectivity filter can be varied in a large range. The physical size of the equivalent element is inversely proportional to the square root of the dielectric constant of the material, that is, the larger the dielectric constant, the smaller the required element size, but the parasitic parameter influence is also larger. In order to meet the requirements of low insertion loss, high isolation and small size, the dielectric body material with a dielectric constant of 33 is selected in the embodiment of the present application, and the tangent angle of the dielectric loss is 0.001.

[0038] In one embodiment of the present application, as shown in Figure 11 The bandwidth-adjustable high-selectivity filter has good transmission characteristics and high mutual interference resistance between adjacent channels.

[0039] In summary, the present application provides a band-pass filter based on multi-layer printing technology. It has the following characteristics: flexible bandwidth adjustment: independent control of high and low frequency bandwidth, suitable for diversified frequency requirements; strong miniaturization adaptability: short coupling line performance problem is solved by capacitance compensation, meeting the design of small equipment; high frequency selectivity: combination of four-order topology and coupling optimization, steep passband edge attenuation, strong anti-interference ability.

[0040] Those skilled in the art will appreciate that the embodiments described herein are presented for the purpose of helping the reader to understand the principles of the present application, and should be understood as not limiting the scope of protection of the present application to such specific statements and embodiments. Those skilled in the art can make various other specific modifications and combinations according to the technical inspiration disclosed in the present application without departing from the essence of the present application, and these modifications and combinations are still within the scope of protection of the present application.

Claims

1. A high-selectivity filter with adjustable bandwidth, characterized in that, It includes a ceramic dielectric (1), a circuit layer inside the ceramic dielectric (1), and an external electrode on the outer wall of the ceramic dielectric (1), wherein the external electrode includes an input port (2), an output port (3), and a ground port (4). The circuit layer includes a multi-order microstrip line coupled bandpass filter and a low-pass filter; The multi-order microstrip line coupled bandpass filter includes a first equivalent coupled microstrip line CL1, a second equivalent coupled microstrip line CL2, a third equivalent coupled microstrip line CL3, a fourth equivalent coupled microstrip line CL4, a first equivalent capacitor C1, a second equivalent capacitor C2, a third equivalent capacitor C3, a fifth equivalent capacitor C5, a sixth equivalent capacitor C6, and a seventh equivalent capacitor C7. The low-pass filter includes a fifth equivalent coupled microstrip line CL5, a sixth equivalent coupled microstrip line CL6, a seventh equivalent coupled microstrip line CL7, an eighth equivalent coupled microstrip line CL8, an eighth equivalent capacitor C8, and a ninth equivalent capacitor C9. One end of the eighth equivalent capacitor C8 is connected to one end of the first equivalent coupling microstrip line CL1 and one end of the fifth equivalent coupling microstrip line CL5, respectively. Its other end is connected to one end of the second equivalent coupling microstrip line CL2 and one end of the sixth equivalent coupling microstrip line CL6, respectively. The other ends of the fifth equivalent coupling microstrip line CL5 and the sixth equivalent coupling microstrip line CL6 are both grounded. The other end of the first equivalent coupling microstrip line CL1 is connected to the input port (2), one end of the first equivalent capacitor C1, and one end of the second equivalent capacitor C2, respectively. The other end of the second equivalent coupling microstrip line CL2 is connected to the other end of the second equivalent capacitor C2, one end of the third equivalent capacitor C3, and one end of the fifth equivalent capacitor C5, respectively. One end of the ninth equivalent capacitor C9 is connected to the seventh equivalent coupling microstrip line... One end of microstrip line CL7 is connected to one end of the third equivalent coupling microstrip line CL3, and the other end is connected to one end of the eighth equivalent coupling microstrip line CL8 and one end of the fourth equivalent coupling microstrip line CL4. The other end of the seventh equivalent coupling microstrip line CL7 and the other end of the eighth equivalent coupling microstrip line CL8 are both grounded. The other end of the third equivalent coupling microstrip line CL3 is connected to one end of the fifth equivalent capacitor C5 and one end of the sixth equivalent capacitor C6. The other end of the fourth equivalent coupling microstrip line CL4 is connected to the output port (3), the other end of the sixth equivalent capacitor C6 and one end of the seventh equivalent capacitor C7. The other end of the first equivalent capacitor C1, the other end of the third equivalent capacitor C3, the other end of the fifth equivalent capacitor C5 and the other end of the seventh equivalent capacitor C7 are all grounded.

2. The bandwidth-adjustable high selectivity filter according to claim 1, characterized in that, The circuit layer includes: First circuit layer: The first circuit layer includes a first electrode plate P1, a second electrode plate P2, a third electrode plate P3, a fourth electrode plate P4, a first via H1, a second via H2, a third via H3, a fourth via H4, a fifth via H5, a sixth via H6, a seventh via H7 and an eighth via H8. Second circuit layer: The second circuit layer includes a fifth electrode plate P5, a sixth electrode plate P6, a first via H1, a second via H2, a third via H3, a fourth via H4, a sixth via H6 and a seventh via H7; Third circuit layer: The third circuit layer includes a seventh electrode plate P7, an eighth electrode plate P8, a first via H1, a second via H2, a third via H3, a fourth via H4, a ninth via H9, and a tenth via H10; Fourth circuit layer: The fourth circuit layer includes a ninth electrode plate P9, a tenth electrode plate P10, an eleventh electrode plate P11, a first via H1, a second via H2, a third via H3, a fourth via H4, a ninth via H9, a tenth via H10, an eleventh via H11, and a twelfth via H12. Fifth circuit layer: The fifth circuit layer includes the twelfth electrode plate P12, the thirteenth electrode plate P13, the fourteenth electrode plate P14, the ninth via H9, the tenth via H10, the eleventh via H11 and the twelfth via H12; Sixth circuit layer: The sixth circuit layer includes the fifteenth electrode plate P15 and via group H111; Seventh circuit layer: The seventh circuit layer includes a sixteenth electrode plate P16, an input port (2) and an output port (3), wherein the sixteenth electrode plate P16 serves as the ground port (4).

3. The bandwidth-adjustable high selectivity filter according to claim 2, characterized in that, The first electrode plate P1, the fifth electrode plate P5 and the twelfth electrode plate P12 are connected end to end through the first via H1 and the fifth via H5, and together they form the first equivalent coupled microstrip line CL1. The second electrode plate P2, the seventh electrode plate P7 and the thirteenth electrode plate P13 are connected end to end via the second via H2 and the sixth via H6, and together they form the second equivalent coupled microstrip line CL2. The third electrode plate P3, the eighth electrode plate P8 and the thirteenth electrode plate P13 are connected end to end via the third via H3 and the seventh via H7, and together they form the third equivalent coupled microstrip line CL3. The fourth electrode plate P4, the sixth electrode plate P6 and the fourteenth electrode plate P14 are connected end to end via the fourth via H4 and the eighth via H8, and together they form the fourth equivalent coupling microstrip line CL4. The fifth electrode plate P5 and the fifteenth electrode plate P15 are connected end to end through the fifth via H5, together forming the fifth equivalent coupled microstrip line CL5. The seventh electrode plate P7 and the fifteenth electrode plate P15 are connected end to end through the sixth via H6, together forming the sixth equivalent coupling microstrip line CL6. The eighth electrode plate P8 and the fifteenth electrode plate P15 are connected end to end through the twelfth via H12, together forming the seventh equivalent coupling microstrip line CL7. The sixth electrode plate P6 and the fifteenth electrode plate P15 are connected end to end through the tenth via H10, together forming the eighth equivalent coupled microstrip line CL8. The twelfth electrode plate P12 and the fifteenth electrode plate P15 are coupled together through interlayer coupling to form the first equivalent capacitance C1; The twelfth electrode plate P12, the thirteenth electrode plate P13 and the ninth electrode plate P9 are coupled together through interlayer coupling to form the second equivalent capacitance C2; The thirteenth electrode plate P13 and the fifteenth electrode plate P15 are coupled together through interlayer coupling to form the third equivalent capacitor C3 and the fifth equivalent capacitor C5. The tenth electrode plate P10, the thirteenth electrode plate P13, and the fourteenth electrode plate P14 are coupled together through interlayer coupling to form the sixth equivalent capacitor C6. The fourteenth electrode plate P14 and the fifteenth electrode plate P15 are coupled together through interlayer coupling to form the seventh equivalent capacitor C7. The fifth electrode plate P5 and the seventh electrode plate P7 are coupled together through interlayer coupling to form the eighth equivalent capacitor C8. The sixth electrode plate P6 and the eighth electrode plate P8 are coupled together through interlayer coupling to form the ninth equivalent capacitor C9.

4. The bandwidth-adjustable high selectivity filter according to claim 2, characterized in that, The fifteenth electrode plate P15 is a large-area grounding layer, which is connected to the grounding port (4) on the outer electrode through the via group H111.

5. The bandwidth-adjustable high selectivity filter according to claim 2, characterized in that, The thickness from the first circuit layer to the top layer of the high selectivity filter is 150 μm; The thickness of the second circuit layer to the first circuit layer is 695 μm; The thickness from the third circuit layer to the second circuit layer is 25 μm; The thickness from the fourth circuit layer to the third circuit layer is 559 μm; The thickness of the fifth circuit layer to the fourth circuit layer is 52 μm; The thickness of the sixth circuit layer to the fifth circuit layer is 83 μm; The thickness of the seventh circuit layer to the sixth circuit layer is 83 μm.

6. The bandwidth-adjustable high-selectivity filter according to claim 1, characterized in that, The manufacturing process of the high selectivity filter includes: manufacturing based on multilayer printed circuit board technology, manufacturing based on low temperature co-fired ceramic technology, manufacturing based on IPD technology, or manufacturing based on CMOS semiconductor technology. The embedded metal material used in the circuit layer is copper or palladium-silver.

7. The bandwidth-adjustable high selectivity filter according to claim 1, characterized in that, The ceramic dielectric body (1) has dimensions of 3.2mm × 2.5mm × 1.5mm.

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