High in-band rejection broadband band elimination filter

Abstract

The invention relates to the technical field of microwave communication, and discloses a high in-band rejection broadband band elimination filter. The filter is based on a micro-strip resonator, and a micro-strip open-circuit branch knot is loaded in the middle of the micro-strip resonator to form an axial symmetry structure. The structure is divided into three groups of parts with the same characteristic impedance along a symmetry axis, and the working bandwidth and the in-band suppression level of the filter can be flexibly adjusted by independently adjusting the impedance ratio of each group. The structure is simple, narrow slits do not need to be machined, and the machining difficulty and cost are remarkably reduced. Compared with the prior art, about 90% of relative working bandwidth can be obtained while 40dB high in-band suppression is realized, and the problem that high in-band suppression and broadband performance are difficult to consider at the same time is effectively solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of microwave communication technology, in particular to a high in-band suppression wideband band-stop filter. BACKGROUND

[0002] A band-stop filter is a frequency selective device used in microwave and millimeter wave frequency bands, widely used in communication, radar, electronic countermeasures and other fields. Its main function is to suppress signals in a specific frequency band while allowing signals in other frequency bands to pass through, thereby achieving precise control of signal frequency. Traditional high in-band suppression level wideband band-stop filters mostly use resonant cavity structures or electromagnetic bandgap (EBG) based structures, but these methods have some limitations. For example, the filter with resonant cavity structure usually has large volume and heavy weight, which is difficult to meet the demand of modern miniaturized devices; while the filter based on electromagnetic bandgap may face problems such as narrow bandwidth, insufficient in-band suppression level, high processing precision requirement, etc. With the rapid development of modern communication technology, the performance requirements of high in-band suppression level wideband band-stop filter are becoming higher and higher, including wider stop band range, higher in-band suppression level, smaller size and higher reliability. Therefore, it is of great practical significance and broad application prospect to develop a new type of high in-band suppression wideband band-stop filter that overcomes the shortcomings of existing technology while maintaining high performance. SUMMARY

[0003] The purpose of the present application is to provide a high in-band suppression wideband band-stop filter, which has a relative operating bandwidth of about 90% for 40 dB in-band suppression, much higher than the level of existing band-stop filters.

[0004] In order to achieve the above purpose, the technical scheme adopted is as follows: A high in-band suppression wideband band-stop filter, comprising a microstrip resonator, wherein an open stub is loaded in the middle of the microstrip resonator; the band-stop filter is an axisymmetric structure, divided into three groups of microstrip lines along the symmetry axis, and the characteristic impedance of each group of microstrip lines is the same; the three groups of microstrip lines are respectively a first group of microstrip lines, a second group of microstrip lines and a third group of microstrip lines, each group of microstrip lines contains two symmetrically arranged microstrip lines, and the characteristic impedance of each group of microstrip lines is independently adjusted; the input port and the output port of the band-stop filter are symmetric about the symmetry axis, and all the microstrip lines are directly connected without coupling microstrip line structure.

[0005] Further, the microstrip line is a strip line, a parallel coupled microstrip line, a suspended strip line or a common mode waveguide transmission line.

[0006] Further, the first group of microstrip lines comprises a first microstrip line and a second microstrip line, the second group of microstrip lines comprises a third microstrip line and a fourth microstrip line, and the third group of microstrip lines comprises a fifth microstrip line and a sixth microstrip line; the first microstrip line is connected to the third microstrip line, and the input port is connected to the connection between the first microstrip line and the third microstrip line; the second microstrip line is connected to the fourth microstrip line, and the output port is connected to the connection between the second microstrip line and the fourth microstrip line; the fifth microstrip line is connected to the sixth microstrip line, and forms a complete connection with the third microstrip line and the fourth microstrip line through a connecting line.

[0007] Further, the characteristic impedance ratio of the three groups of microstrip lines is: K 1=Z2 / Z1, K 2=Z3 / Z2; wherein Z1 is the characteristic impedance of the first group of microstrip lines, Z2 is the characteristic impedance of the second group of microstrip lines, and Z3 is the characteristic impedance of the third group of microstrip lines, K 1 is the characteristic impedance ratio of the second group of microstrip lines to the first group of microstrip lines, K 2 is the characteristic impedance ratio of the third group of microstrip lines to the second group of microstrip lines.

[0008] Further, K 1 and K 2 are both in the range of 0.15 to 6.5.

[0009] Further, the center frequency of the band-stop filter is designed in the frequency range of 0.5 GHz to 10 GHz. Further, the band-stop filter is implemented by using a circuit substrate with a dielectric constant of 2.0 to 10.0.

[0010] Further, the dielectric constant of the circuit substrate is 3.55±0.1, the thickness is 0.508mm±20%, and the loss tangent is not greater than 0.003.

[0011] Further, the structural parameters of the microstrip lines satisfy: W 0=1.10mm~1.20mm, wherein W 0 is the width of the first microstrip line and the second microstrip line; W 1=3.90mm~4.10mm, wherein W 1 is the width of the third microstrip line and the fourth microstrip line; W 2=0.08mm~0.12mm, wherein W 2 is the width of the microstrip line connection transition section; W 3=3.90mm~4.10mm, wherein W3 represents the width of the fifth and sixth microstrip lines; L 1 = 12.6mm~13.0mm, where L 1 represents the lengths of the first microstrip line and the second microstrip line; L 2 = 14.0mm~14.4mm, where L 2 represents the lengths of the third and fourth microstrip lines; L 3 = 12.9mm~13.3mm, of which L 3 represents the lengths of the fifth and sixth microstrip lines; D 1 = 0.9mm~1.1mm, where D 1 represents the spacing between the first microstrip line and the third microstrip line; D 2 = 0.9mm~1.1mm, where D 2 represents the spacing between the second and fourth microstrip lines.

[0012] Furthermore, the electrical length of each microstrip line is 90°, corresponding to the center frequency of the band-stop filter.

[0013] The beneficial effects of this invention are reflected in: 1. This invention provides a high in-band rejection broadband bandstop filter with a universal structure that is easy to implement. The core structure of the filter is not limited to a microstrip line form and can be equivalently applied to various transmission line structures such as striplines, suspended striplines, or coplanar waveguides, thus broadening its application scenarios and implementation flexibility.

[0014] 2. The present invention provides a high in-band rejection broadband bandstop filter that is simple to fabricate and low in cost. This filter employs a directly connected microstrip line structure, eliminating the need to fabricate narrow coupling gaps requiring extremely high precision. This not only reduces fabrication difficulty and manufacturing costs but also improves product consistency and reliability.

[0015] 3. The high in-band rejection broadband bandstop filter provided by this invention has an in-band rejection of 40dB and a relative operating bandwidth of approximately 90%, which is far higher than the level of existing broadband bandstop filters. Specifically, this invention optimizes the impedance ratio of three sets of symmetrical microstrip lines, enabling the filter to achieve approximately 90% relative operating bandwidth while maintaining a high in-band rejection level (e.g., 40dB). This performance is far superior to existing similar broadband bandstop filters, effectively solving the technical contradiction of balancing high rejection and wide bandwidth. Attached Figure Description

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed in the embodiments will be briefly introduced as follows. Obviously, the accompanying drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained based on these drawings.

[0017] Figure 1 A structural schematic diagram of a high-in-band rejection wideband band-stop filter provided by an embodiment of the present application is shown in the following figure. Figure 2 An odd-even mode equivalent circuit diagram of a high-in-band rejection wideband band-stop filter provided by an embodiment of the present application is shown in the following figure. Figure 3 A response diagram of a band-stop filter in different impedance ratios provided by an embodiment of the present application is shown in the following figure. Figure 4 A structural layout diagram of a high-in-band rejection wideband band-stop filter provided by an embodiment of the present application is shown in the following figure. Figure 5 A comparison diagram of test and simulation results of a wideband filter provided by an embodiment of the present application is shown in the following figure.

[0018] Explanation of reference signs: 1, first microstrip line; 2, second microstrip line; 3, third microstrip line; 4, fourth microstrip line; 5, fifth microstrip line; 6, sixth microstrip line; 7, input port (port 1); 8, output port (port 2). DETAILED DESCRIPTION

[0019] The embodiments of the present application are described below through specific and concrete examples. Those skilled in the art can easily understand other advantages and effects of the present application from the content disclosed in the present specification. The present application can also be implemented or applied through other different specific embodiments, and each detail in the present specification can be modified or changed based on different views and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0020] The specific embodiments of the present application are described in further detail below in combination with the accompanying drawings and embodiments.

[0021] An embodiment of the present application provides a high-in-band rejection wideband band-stop filter, as shown in the following figure. Figure 1As shown, the high-in-band rejection wideband band-stop filter comprises a microstrip resonator, which is loaded with an open-circuit stub in the middle; the band-stop filter is an axisymmetric structure, which is divided into three groups of microstrip lines along the symmetry axis, and the characteristic impedance of each group of microstrip lines is the same; the three groups of microstrip lines are respectively a first group of microstrip lines, a second group of microstrip lines and a third group of microstrip lines, each group of microstrip lines comprises two symmetrically arranged microstrip lines, and the characteristic impedance of each group of microstrip lines is independently adjusted; the input port 7 and the output port 8 of the band-stop filter are symmetric about the symmetry axis, and all the microstrip lines are directly connected without a coupled microstrip line structure.

[0022] The core function of the filter is to realize the signal suppression of a wide frequency band based on the combined action of multi-mode resonance and impedance mismatch. Specifically, the microstrip resonator and the open-circuit stub loaded in the middle jointly constitute a resonant structure capable of exciting multiple resonance modes. When the frequency of the input signal is consistent with the resonant frequency of the structure, the filter will produce strong resonance at the corresponding frequency point, so that the signal cannot be effectively transmitted to the output port, thereby forming a stopband near the frequency point and realizing signal suppression. Through the axisymmetric three-group microstrip line structure, multiple adjacent resonance points can be accurately controlled and combined. By independently adjusting the characteristic impedance ratios (i.e., adjusting K 1=Z2 / Z1, K 2=Z3 / Z2) of the three groups of microstrip lines, the positions and coupling strengths of these resonance points on the frequency axis can be flexibly adjusted, so that they are close to each other and connected into a flat and wide suppression band, which is the reason why the present application can realize a working bandwidth far exceeding that of a conventional band-stop filter. The structure in which all the microstrip lines are directly connected without a coupling gap means that the parasitic parameters on the signal path are reduced, and the energy radiation loss is reduced. This makes the passband insertion loss of the filter smaller, the frequency response closer to the ideal characteristic, and the processing technology simplified. The symmetric design of the input and output ports ensures that the filter has good port matching and consistency of signal transmission.

[0023] In some embodiments, the microstrip line is a strip line, a parallel-coupled microstrip line, a suspended strip line or a common-mode waveguide transmission line.

[0024] The core of the present application lies in the electromagnetic field distribution and resonance characteristics jointly defined by the axisymmetric multi-section impedance structure and the open-circuit stub loaded in the middle. Regardless of the transmission line structure described above, the working principle is uniform and equivalent. For example, Figure 1The basic topology shown, including input port 7, output port 8, three sets of symmetric transmission line segments and open stubs in the middle, defines the impedance distribution along the signal path and the position of the current antinodes / nodes. This topology is the fundamental circuit model that generates the required multi-mode resonances, and in turn forms the broadband stopband function. When this circuit model is mapped from microstrip line to stripline, suspended stripline, coplanar waveguide and other transmission line structures, the process of merging multiple resonance points and forming a wide stopband by adjusting the characteristic impedance ratio of the three sets of line segments remains unchanged.

[0025] For stripline or suspended stripline, when such shielding structure is adopted, the electromagnetic field is completely confined between the conductor and the ground plate, which can significantly reduce the radiation loss and improve the power capacity and frequency selectivity of the filter. It corresponds to Figure 1 The characteristic impedance of each line segment in the middle is achieved by adjusting the width of the center conductor and the spacing from the upper and lower ground plates.

[0026] For coplanar waveguide transmission line, this structure places the signal line and the ground line in the same plane, making it easy to integrate series and parallel elements. In this structure, Figure 1 The topology shown is converted into line segments and open stubs of coplanar waveguide, and the characteristic impedance of each line segment is adjusted by adjusting the width of the center conductor and the gap width between the two side ground conductors, so as to achieve the same filtering response.

[0027] The flexibility of the above implementation enables the present application to adapt to the needs of different application scenarios, for example, coplanar waveguide form can be used in monolithic microwave integrated circuit (MMIC) that requires high integration; stripline or suspended stripline form can be selected in subsystems that require high power and low loss. Although the physical structure changes, the core advantage of the filter, which does not require processing of narrow coupling gaps, is preserved, and its characteristics of easy processing, consistent performance and low cost are reflected in different transmission line forms.

[0028] Therefore, the present embodiment proves that the design concept of the broadband bandstop filter of the present application is universal, and its protection scope is not limited to a specific transmission line implementation, but covers all physical structures that can realize the circuit topology and working principle described above.

[0029] In some embodiments, as Figure 1As shown, the specific structural connection relationship of the high-in-band rejection wideband bandstop filter is as follows: the first group of microstrip lines includes a first microstrip line 1 and a second microstrip line 2, the second group of microstrip lines includes a third microstrip line 3 and a fourth microstrip line 4, and the third group of microstrip lines includes a fifth microstrip line 5 and a sixth microstrip line 6. Among them, the first microstrip line 1 and the second microstrip line 2 are symmetrically arranged about the symmetry axis, the third microstrip line 3 and the fourth microstrip line 4 are symmetrically arranged about the symmetry axis, and the fifth microstrip line 5 and the sixth microstrip line 6 are symmetrically arranged about the symmetry axis. The signal path connection is as follows: one end of the first microstrip line 1 is connected to one end of the third microstrip line 3, and the input port 7 is connected at the connection of the first microstrip line 1 and the third microstrip line 3; one end of the second microstrip line 2 is connected to one end of the fourth microstrip line 4, and the output port 8 is connected at the connection of the second microstrip line 2 and the fourth microstrip line 4. The fifth microstrip line 5 and the sixth microstrip line 6 are directly connected to form an integral branch, and the branch is connected to the other end of the third microstrip line 3 and the other end of the fourth microstrip line 4 through the connecting lines, thereby forming a T-shaped connection at the center of the structure and forming an open-circuit branch loaded in the middle of the resonator.

[0030] The working principle is as follows: after the radio frequency signal is injected from the input port 7, it will flow to the first microstrip line 1 and the third microstrip line 3 simultaneously, equally, and in phase. Due to the complete symmetry of the structure, the signals flowing through the upper and lower paths have consistent characteristics. The signal propagates along the third microstrip line 3 and the fourth microstrip line 4, and excites the open-circuit branch composed of the fifth microstrip line 5 and the sixth microstrip line 6. The branch cooperates with the upper and lower main paths to excite multiple resonance modes. When the signal frequency is near these resonance frequencies, most of the signal energy will be trapped in the resonant structure, forming strong reflection and unable to continue transmission, thereby producing deep suppression points in the frequency response. By independently adjusting the characteristic impedances of the first group of microstrip lines, the second group of microstrip lines, and the third group of microstrip lines, the frequency positions of these resonance points and their coupling strengths can be accurately controlled. When the three groups of impedance ratios are optimized to a specific range (for example, 0.15 to 6.5), multiple resonance points are brought closer and merged, ultimately forming a flat stopband with a clear center frequency and a very wide relative bandwidth (for example, about 90% under 40dB suppression). At frequencies outside the stopband, the signal can pass through the structure smoothly and finally be output at the output port 8 by the second microstrip line 2 and the fourth microstrip line 4.

[0031] In some embodiments, the performance optimization of the high-in-band rejection wideband bandstop filter is achieved through precise electrical length design. Specifically, the electrical lengths of the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, and the sixth microstrip line 6 are all designed to be 90°, which corresponds to the center frequency of the bandstop filter.

[0032] The 90° electrical length at the center frequency makes each section of microstrip line equivalent to a quarter wavelength transmission line. This specific electrical length creates a 90° phase shift in the microwave network, which establishes the precise phase basis for the entire filter structure and is the key to generating the pre-set resonant behavior. The open-circuit stub (formed by the fifth microstrip line 5 and the sixth microstrip line 6) exhibits specific impedance characteristics at the center frequency due to its total electrical length (two sections of 90° microstrip line in series), which, in combination with the other four sections of 90° microstrip line (1, 2, 3, 4), precisely excites and controls multiple resonant modes. These resonant modes, built from 90° basic units with the center frequency as the reference, are the physical basis for merging them into a wide stopband by adjusting the impedance ratios. The uniform 90° electrical length design ensures the symmetry and predictability of the filter response. It enables the symmetrical distribution of multiple resonant points around the center frequency, providing the most favorable conditions for smoothly merging these resonant points and ultimately forming a wide and flat stopband by adjusting the specific impedance ratios of the three groups of microstrip lines (1, 2, 3, 4, 5, 6). K 1、 K 2) to form a wide and flat stopband.

[0033] In some embodiments, the application frequency range of the high in-band suppression wideband bandstop filter and the implementation medium have specific preferred ranges. The center frequency of the bandstop filter is designed in the microwave frequency range of 0.5 GHz to 10 GHz. This frequency range covers multiple important communication and radar application frequency bands from L-band to X-band, reflecting the universality and wide applicability of the design.

[0034] To achieve the above-mentioned filter, a circuit substrate with a dielectric constant of 2.0 to 10.0 is preferably used as the support and propagation medium. The circuit substrate is used to carry and constitute all physical structures of the filter, including the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, the sixth microstrip line 6, and the input port 7 and the output port 8.

[0035] In a specific and optimized implementation scheme, the material parameters of the circuit substrate are further limited as follows: the dielectric constant is 3.55±0.1, the thickness is 0.508 mm±20%, and the loss tangent is not greater than 0.003. This set of parameters defines a high-performance, low-loss board specification (for example, a substrate that meets the Rogers 4003c standard). Using the above-mentioned parameters, the substrate can ensure that the filter has extremely low insertion loss, good temperature stability, and consistent frequency response while achieving a wide stopband performance of about 90%, thereby meeting the requirements of high-performance microwave systems for filter components. The substrate is also used to accurately manufacture the first microstrip line 1 to the sixth microstrip line 6 and the input port 7 and the output port 8.

[0036] The feasibility and progressiveness of the present application will be further illustrated below with a specific example.

[0037] Specific example: This example lists a high in-band rejection wideband band-stop filter, the structural schematic diagram of which is shown in Figure 1 In this example, the center frequency of the differential phase shifter is set to 3 GHz. This example uses a Rogers 4003c circuit substrate with a dielectric constant of 3.55, a thickness of 0.508 mm, and a loss tangent of 0.0027.

[0038] Figure 2 is the odd and even mode equivalent circuit of the band-stop filter in this example. It can be further theoretically analyzed according to the parameters therein.

[0039] Figure 3 is the response of the band-stop filter under different impedance ratios. Among them K 1 and K 2 are the ratios of characteristic impedances, specifically K 1 = Z2 / Z1, K 2 = Z3 / Z2. For the characteristic impedance of a commonly used microstrip line, which is subject to processing limits and the propagation mode of the microstrip line itself, its value range is generally 20Ω~130Ω, K 1 and K 2 range from 0.15 to 6.5. Therefore, by Figure 3 It can be seen that when K 1 takes a value of 6.5, K 2 takes a value of 0.15, the working bandwidth of the band-stop filter in this example is the largest. At this time, the relative working bandwidth of the band-stop filter under the condition of 40 dB suppression is about 90%, which is much larger than the current level of wideband band-stop filters Figure 4 is the structural layout diagram of the high in-band rejection wideband band-stop filter according to the present application. In this example, the center frequency of the band-stop filter is set to 3 GHz. Among them Figure 4 The parameters in W 0 = 1.15 mm, W 1 = 4 mm, W 2 = 0.1 mm, W 3 = 4 mm, L 1 = 12.8 mm, L 2 = 14.2 mm, L 3 = 13.1 mm, D 1 = 1 mm, D 2 = 1 mm. Among them W 0 is the width of the first microstrip line 1 and the second microstrip line 2; W1 is the width of the third microstrip line 3 and the fourth microstrip line 4; W 2 is the width of the microstrip line connection transition section for connecting the third microstrip line 3 and the fifth microstrip line 5, and the fourth microstrip line 4 and the sixth microstrip line 6; W 3 is the width of the fifth microstrip line 5 and the sixth microstrip line 6; L 1 is the length of the first microstrip line 1 and the second microstrip line 2; L 2 is the length of the third microstrip line 3 and the fourth microstrip line 4; L 3 is the length of the fifth microstrip line 5 and the sixth microstrip line 6; D 1 is the spacing between the first microstrip line 1 and the third microstrip line 3; D 2 is the spacing between the second microstrip line 2 and the fourth microstrip line 4.

[0040] Figure 5 The test and simulation results of the high-bandwidth-in-rejection wideband band-stop filter are given. Figure 5 It can be seen that the results obtained by the network analyzer test are consistent with the results obtained by the three-dimensional simulation software, which proves the correctness of the above work. At the same time, the 40dB bandwidth-in-rejection bandwidth obtained by the test is slightly larger than the simulation result, which is caused by the processing error and is within a reasonable range.

[0041] The above embodiments are only used to illustrate the present application, and are not intended to limit the present application. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, all equivalent technical solutions belong to the scope of the present application, and the patent protection scope of the present application should be defined by the claims.

Claims

1. A high in-band rejection broadband bandstop filter, characterized in that, The system includes a microstrip resonator with an open-circuit stub in the middle; the band-stop filter has an axisymmetric structure, divided into three groups of microstrip lines along the axis of symmetry, each group having the same characteristic impedance; the three groups of microstrip lines are the first group, the second group, and the third group, each group containing two symmetrically arranged microstrip lines, and the characteristic impedance of each group can be adjusted independently; the input and output ports of the band-stop filter are symmetrical about the axis of symmetry, and all microstrip lines are directly connected, with no coupled microstrip line structure.

2. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The microstrip line can be a stripline, a parallel-coupled microstrip line, a suspended stripline, or a common-mode waveguide transmission line.

3. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The first group of microstrip lines includes a first microstrip line and a second microstrip line; the second group of microstrip lines includes a third microstrip line and a fourth microstrip line; the third group of microstrip lines includes a fifth microstrip line and a sixth microstrip line; the first microstrip line is connected to the third microstrip line; and the input port is connected at the connection point between the first microstrip line and the third microstrip line. The second microstrip line is connected to the fourth microstrip line, and the output port is connected at the junction of the second microstrip line and the fourth microstrip line; The fifth microstrip line is connected to the sixth microstrip line, and forms a complete connection with the third and fourth microstrip lines through a connecting line.

4. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The characteristic impedance ratio of the three sets of microstrip lines is: K 1 = Z2 / Z1, K 2 = Z3 / Z2; where Z1 is the characteristic impedance of the first group of microstrip lines, Z2 is the characteristic impedance of the second group of microstrip lines, and Z3 is the characteristic impedance of the third group of microstrip lines. K 1 represents the ratio of the characteristic impedance of the second group of microstrip lines to that of the first group of microstrip lines. K 2 represents the ratio of the characteristic impedance of the third group of microstrip lines to that of the second group of microstrip lines.

5. The high in-band rejection broadband bandstop filter according to claim 4, characterized in that, K 1 and K The value of 2 ranges from 0.15 to 6.

5.

6. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The center frequency of the band-stop filter is designed to be in the range of 0.5 GHz to 10 GHz.

7. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The band-stop filter is implemented using a circuit board with a dielectric constant between 2.0 and 10.

0.

8. The high in-band rejection broadband bandstop filter according to claim 7, characterized in that, The dielectric constant of the circuit board is 3.55±0.1, the thickness is 0.508mm±20%, and the loss tangent is not greater than 0.

003.

9. The high in-band rejection broadband bandstop filter according to claim 3, characterized in that, The structural parameters of the microstrip line satisfy: W 0 = 1.10mm~1.20mm, where W 0 represents the width of the first microstrip line and the second microstrip line; W 1 = 3.90mm~4.10mm, where W 1 represents the width of the third and fourth microstrip lines; W 2 = 0.08mm~0.12mm, where W 2 represents the width of the transition section connecting the microstrip line; W 3 = 3.90mm~4.10mm, where W 3 represents the width of the fifth and sixth microstrip lines; L 1 = 12.6mm~13.0mm, where L 1 represents the lengths of the first microstrip line and the second microstrip line; L 2 = 14.0mm~14.4mm, where L 2 represents the lengths of the third and fourth microstrip lines; L 3 = 12.9mm~13.3mm, of which L 3 represents the lengths of the fifth and sixth microstrip lines; D 1 = 0.9mm~1.1mm, where D 1 represents the spacing between the first microstrip line and the third microstrip line; D 2 = 0.9mm~1.1mm, where D 2 represents the spacing between the second and fourth microstrip lines.

10. The high in-band rejection broadband bandstop filter according to claim 1, characterized in that, The electrical length of each microstrip line is 90°, corresponding to the center frequency of the band-stop filter.

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