Dual-passband filter and communication equipment

Abstract

The embodiment of the utility model relates to the technical field of communication, and particularly discloses a dual-passband filter and communication equipment, the dual-passband filter comprises a substrate and a topological structure, and the topological structure is arranged on the substrate. The topological structure comprises an input end, an output end, a first parallel line, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a first open-circuit branch knot and a second open-circuit branch knot, the input end is connected with one end of the first parallel line, the other end of the first parallel line is connected with the output end, and the output end is connected with the third microstrip line. The other end of the first parallel line, the first micro-strip line, the second micro-strip line and the first open-circuit branch knot are connected in sequence, and one end of the first parallel line, the third micro-strip line, the fourth micro-strip line and the second open-circuit branch knot are connected in sequence. By means of the mode, the topological structure is simple and compact, and miniaturization of the dual-passband filter is facilitated.

Description

Technical Field

[0001] The embodiments of the utility model relate to the field of communication technology, and in particular to a dual-passband filter and communication equipment. Background Art

[0002] With the rapid development and diversification of communication technologies, RF receive front-ends need to process signals across multiple frequency bands and communication formats. To meet this demand, dual-passband filters, as key components of RF front-ends, are widely used in multi-band communication systems to filter and transmit signals across different frequency bands. Dual-passband filters primarily consist of a substrate and a topology. The topology is typically constructed on the substrate and currently consists of multiple parallel lines, microstrip lines, and open branches.

[0003] In the process of implementing the embodiments of the present utility model, the inventors found that the current dual-passband filter structure is complex and not compact, which is not conducive to the miniaturization requirements of the communication system. Utility Model Content

[0004] In view of the above problems, embodiments of the present invention provide a dual-passband filter and a communication device, which overcome the above problems or at least partially solve the above problems.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: to provide a dual-passband filter, including a substrate and a topological structure, the topological structure is arranged on the substrate, and the topological structure includes an input end, an output end, a first parallel line, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a first open branch and a second open branch, wherein the input end is connected to one end of the first parallel line, the other end of the first parallel line is connected to the output end, the other end of the first parallel line, the first microstrip line, the second microstrip line and the first open branch are connected in sequence, and one end of the first parallel line, the third microstrip line, the fourth microstrip line and the second open branch are connected in sequence.

[0006] Optionally, the first parallel line includes a first transmission line and a second transmission line arranged in parallel, one end of the first transmission line is connected to the input end, the other end of the first transmission line is connected to the first microstrip line, the second microstrip line and the first open branch in sequence, one end of the second transmission line is connected to the third microstrip line, the fourth microstrip line and the second open branch in sequence, and the other end of the second transmission line is connected to the output end.

[0007] Optionally, the first transmission line, the second transmission line, the second microstrip line and the fourth transmission line are all arranged in parallel and perpendicular to the first microstrip line, the third microstrip line, the first open branch and the second open branch.

[0008] Optionally, the electrical length of the first transmission line and the electrical length of the second transmission line are both a quarter of the wavelength corresponding to the center frequency of the stop band between the two pass bands, the sum of the electrical length of the first microstrip line, the electrical length of the second microstrip line and the electrical length of the first open-circuit stub is a quarter of the wavelength corresponding to the center frequency of the stop band between the two pass bands, and the sum of the electrical length of the third microstrip line, the electrical length of the fourth microstrip line and the electrical length of the second open-circuit stub is a quarter of the wavelength corresponding to the center frequency of the stop band between the two pass bands.

[0009] Optionally, along the first direction, the length of the first open-circuit stub is less than the length of the first microstrip line, the first transmission line, the first microstrip line, the second microstrip line and the first open-circuit stub enclose a first cavity with a first opening, and / or, along the first direction, the length of the second open-circuit stub is less than the length of the third microstrip line, the second transmission line, the third microstrip line, the fourth microstrip line and the second open-circuit stub enclose a second cavity with a second opening, wherein the first direction is the direction from the first transmission line to the second transmission line.

[0010] Optionally, along the first direction, the distance between the first transmission line and the second transmission line is 0.1 millimeter, and / or, along the first direction, the width of the first transmission line and the second transmission line is 0.1 millimeter, and / or, along the second direction, the length of the first transmission line and the second transmission line is 8.2 millimeters, wherein the second direction is perpendicular to the first direction.

[0011] Optionally, along the first direction, the length of the first microstrip line and the third microstrip line is 1.95 millimeters, and the width of the second microstrip line and the fourth microstrip line is 0.1 millimeter, and / or, along the second direction, the length of the second microstrip line and the fourth microstrip line is 4.9 millimeters, and the width of the first microstrip line and the third microstrip line is 0.1 millimeter.

[0012] Optionally, the other end of the first transmission line is spaced apart from the output end, and the second microstrip line extends away from the other end of the first microstrip line towards the input end, the first cavity is located between the input end and the output end, and the first opening is located on the side of the first cavity close to the input end, and / or, one end of the second transmission line is spaced apart from the input end, and the fourth microstrip line extends away from the other end of the third microstrip line towards the output end, the second cavity is located between the input end and the output end, and the second opening is located on the side of the second cavity close to the output end.

[0013] Optionally, the characteristic impedance of the first microstrip line, the characteristic impedance of the second microstrip line, the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the first open-circuit branch, and the characteristic impedance of the second open-circuit branch are all equal.

[0014] In order to solve the above technical problem, another technical solution adopted by the present invention is: providing a communication device, including the above dual-passband filter.

[0015] The beneficial effects of the embodiment of the present invention are as follows: Different from the prior art, the embodiment of the present invention provides a dual-passband filter and communication equipment, the dual-passband filter includes a substrate and a topological structure, the topological structure is arranged on the substrate, the topological structure includes an input end, an output end, a first parallel line, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a first open-circuit branch and a second open-circuit branch, wherein the input end is connected to one end of the first parallel line, the other end of the first parallel line is connected to the output end, the other end of the first parallel line, the first microstrip line, the second microstrip line and the first open-circuit branch are connected in sequence, and one end of the first parallel line, the third microstrip line, the fourth microstrip line and the second open-circuit branch are connected in sequence. In the above manner, the structure of the topological structure is simple and compact, which is conducive to the miniaturization of the dual-passband filter. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the drawings without paying any creative work.

[0017] Figure 1 Schematic diagram of the topology of the dual-passband filter provided by the embodiment of the present utility model;

[0018] Figure 2 This is a specific schematic diagram of the topological structure of the dual-passband filter provided by an embodiment of the present utility model;

[0019] Figure 3 This is a schematic diagram of a topological structure of an odd-mode form provided by an embodiment of the present utility model;

[0020] Figure 4 This is a schematic diagram of the topological structure of the even mode provided by the embodiment of the present utility model;

[0021] Figure 5 This is a layout diagram of a dual-passband filter example provided by an embodiment of the present utility model;

[0022] Figure 6 yes Figure 5 Parameter diagram of

[0023] Figure 7 This is a diagram of S-parameter simulation results of a dual-passband filter example provided by an embodiment of the present utility model. DETAILED DESCRIPTION

[0024] In order to facilitate the understanding of the present invention, the present invention is described in more detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or there can be one or more centered elements therebetween. When an element is described as "connected to" another element, it can be directly connected to the other element, or there can be one or more centered elements therebetween. The terms "vertical", "horizontal", "left", "right" and similar expressions used in this specification are for illustrative purposes only.

[0025] Unless otherwise defined, all technical and scientific terms used in this specification have the same meanings as those commonly understood by those skilled in the art to which this utility model belongs. The terms used in this specification and in the description of this utility model are only for the purpose of describing specific embodiments and are not intended to limit the utility model. The term "and / or" used in this specification includes any and all combinations of one or more of the relevant listed items.

[0026] The dual-passband filter includes a substrate (not shown) and a topology structure 100 , wherein the topology structure 100 is disposed on the substrate.

[0027] For the above topology 100, see Figure 1 and Figure 2 The topology structure 100 includes an input terminal 10, a first parallel line 20, a first microstrip line 30, a second microstrip line 31, a third microstrip line 32, a fourth microstrip line 33, a first open stub 40, a second open stub 41, and an output terminal 50. The first parallel line 20 includes a first transmission line 201 and a second transmission line 202 arranged in parallel along a first direction x.

[0028] Specifically, the input terminal 10, the first transmission line 201, the first microstrip line 30, the second microstrip line 31, and the first open stub 40 are connected in sequence, one end of the second transmission line 202 is connected in sequence to the third microstrip line 32, the fourth microstrip line 33, and the second open stub 41, and the other end of the second transmission line 202 is connected to the output terminal 50. The first transmission line 201, the second transmission line 202, the second microstrip line 31, and the fourth microstrip line 33 are all arranged in parallel and perpendicular to the first microstrip line 30, the third microstrip line 32, the first open stub 40, and the second open stub 41. The first transmission line 201, the second transmission line 202, the second microstrip line 31, and the fourth microstrip line 33 all extend along a first direction x, and the first microstrip line 30, the third microstrip line 32, the first open stub 40, and the second open stub 41 all extend along a second direction y.

[0029] It should be noted that the first direction x is the direction from the first transmission line 201 to the second transmission line 202 , and the second direction y is perpendicular to the first direction x.

[0030] In some embodiments, the electrical length of the first transmission line 201 and the electrical length of the second transmission line 202 are both one-quarter wavelength corresponding to the stopband center frequency between the two passbands, the electrical length of the first microstrip line 30, the electrical length of the second microstrip line 31 and the electrical length of the first open-circuit branch 40 are summed up to one-quarter wavelength corresponding to the stopband center frequency between the two passbands, and the electrical length of the third microstrip line 32, the electrical length of the fourth microstrip line 33 and the electrical length of the second open-circuit branch 41 are summed up to one-quarter wavelength corresponding to the stopband center frequency between the two passbands.

[0031] In some embodiments, the characteristic impedance of the first microstrip line 30, the characteristic impedance of the second microstrip line 31, the characteristic impedance of the third microstrip line 32, the characteristic impedance of the fourth microstrip line 33, the characteristic impedance of the first open-circuit stub 40 and the characteristic impedance of the second open-circuit stub 41 are all equal and are all Z1.

[0032] It should be noted that the above topology 100 has four transmission poles and three transmission zeros. The analysis process using the even-odd mode analysis method is as follows:

[0033] See also Figure 3 , Figure 3 It is an odd-mode form of the topology 100, wherein the odd-mode transmission line 203, the first microstrip line 30, the second microstrip line 31 and the first open-circuit stub 40 are connected in sequence, the odd-mode transmission line 203 and the second microstrip line 31 are arranged in parallel along the first direction x, the first microstrip line 30 and the first open-circuit stub 40 are both perpendicular to the odd-mode transmission line 203 and the second microstrip line 31, the electrical length of the odd-mode transmission line 203 is a quarter wavelength corresponding to the center frequency of the stop band between the two pass bands, and the characteristic impedance of the odd-mode transmission line 203 is Z ooWhen the input admittance Y ino When it is zero, it can be obtained that the topology 100 has two odd-mode transmission poles f op1 、f op2 , the frequencies corresponding to the two odd-mode transmission poles are,

[0034]

[0035] Where f0 is the center frequency of the stopband between the two passbands.

[0036] See also Figure 4 , Figure 4 This is an even-mode version of the topology 100, wherein the even-mode transmission line 204, the first microstrip line 30, the second microstrip line 31, and the first open-circuit stub 40 are sequentially connected, the even-mode transmission line 204 and the second microstrip line 31 are arranged in parallel, and the first microstrip line 30 and the second microstrip line 31 are both perpendicular to the even-mode transmission line 204 and the second microstrip line 31. The electrical length of the even-mode transmission line 204 is the center frequency of the stop band between the two pass bands, and the characteristic impedance of the even-mode transmission line 204 is Z oe When the input admittance Y ine When it is zero, it can be obtained that the topology 100 has two even-mode transmission poles f ep1 、f ep2 , the frequencies corresponding to the two even-mode transmission poles are,

[0037]

[0038] Where f0 is the center frequency of the stopband between the two passbands.

[0039] Next, the ABCD matrices of the cascade resonators constituting the topological structure 100 are multiplied in sequence to obtain the ABCD matrix corresponding to the topological structure 100, and the ABCD matrix of the topological structure 100 is converted into the corresponding S matrix. 21 When |=0, it can be obtained that the topology 100 has three transmission zeros f z1 、f z2 、f z3 , the frequencies corresponding to the three transmission zeros are,

[0040] f z1 =0,f z2 =f0,f z3 =2f0.

[0041] From the above analysis, it can be seen that the topology 100 has two odd-mode transmission poles, two even-mode transmission poles and three transmission zeros, and the relative positions of the corresponding frequencies are, f z1 <f ep1 <f op1 <f z2<f op2 <f ep2 <f z3 , and the relative position relationship is not affected by the parameter Z oo , Z oe and the numerical value of Z1. Therefore, based on the above topology 100, a dual-passband filter can be designed, which has a first passband and a second passband, and the frequency range corresponding to the first passband is smaller than the frequency range corresponding to the second passband. Two transmission poles in each of the first passband and the second passband ensure flatness within each passband, while a transmission zero in the frequency range below the first passband and above the second passband ensures high selectivity, and a transmission zero between the first passband frequency range and the second passband frequency range ensures high isolation.

[0042] The present invention also provides a simulation experiment example of the above dual-passband filter, please refer to Figure 5 and Figure 6 Along the first direction x, the length of the first open stub 40 is less than the length of the first microstrip line 30. The first transmission line 201, the first microstrip line 30, the second microstrip line 31, and the first open stub 40 enclose a first cavity 60 with a first opening 601. Along the first direction x, the length of the second open stub 41 is less than the length of the third microstrip line 32. The second transmission line 202, the third microstrip line 32, the fourth microstrip line 33, and the second open stub 41 enclose a second cavity 70 with a second opening 701. One end of the first transmission line 201 is connected to the input end 10, and the other end of the first transmission line 201 is spaced apart from the output end 50. One end of the second microstrip line 31 is connected to the first microstrip line 30, and the other end of the second microstrip line 31 extends away from the first microstrip line 30 toward the input end 10. The first cavity 60 is located between the input end 10 and the output end 50, and the first opening 601 is located on the side of the first cavity 60 closer to the input end 10. One end of the second transmission line 202 is spaced apart from the input end 10, and the other end of the second transmission line 202 is connected to the output end 50. One end of the fourth microstrip line 33 is connected to the third microstrip line 32, and the other end of the fourth microstrip line 33 extends away from the third microstrip line 32 toward the output end 50. The second cavity 70 is located between the input end 10 and the output end 50, and the second opening 701 is located on the side of the second cavity 70 close to the output end 50.

[0043] The size of the substrate is 11.8 mm*5.6 mm, the thickness is 0.813 mm, the dielectric constant is 3.38, and the dielectric loss is 0.0022. A set of parameters for the topology 100 is set as follows: P =8.2 mm,s P =0.1 mm, w P=0.1 mm, l1=1.95 mm, l2=4.9 mm, l3=1.7 mm, w1=0.1 mm. P 、w P are the physical length and physical width of the first transmission line 201 and the second transmission line 202, respectively. P is the spacing between the first transmission line 201 and the second transmission line 202, are the physical lengths of the first microstrip line 30 and the third microstrip line 32, l1 is the physical length of the first microstrip line 30 and the third microstrip line 32, l2 is the physical length of the second microstrip line 31 and the fourth microstrip line 33, l3 is the physical length of the first open stub 40 and the second open stub 41, and w1 is the physical width of the first microstrip line 30, the second microstrip line 31, the third microstrip line 32, the fourth microstrip line 33, the first open stub 40 and the second open stub 41.

[0044] See also Figure 7 , Figure 7 The following is the S-parameter simulation result for the above simulation example. Within the first passband, the impedance bandwidth with a reflection coefficient less than -10 dB ranges from 2.502 to 3.928 GHz, with a passband center frequency of 3.215 GHz, an absolute passband bandwidth of 1.426 GHz, and a relative passband bandwidth of 44.4%. Within the second passband, the impedance bandwidth with a reflection coefficient less than -10 dB ranges from 8.064 to 9.358 GHz, with a passband center frequency of 8.711 GHz, an absolute passband bandwidth of 1.294 GHz, and a relative passband bandwidth of 14.9%. It can be seen that the dual-passband filter based on topology 100 is a wide dual-passband filter. Within the first passband, the maximum insertion loss is 0.49 dB; within the second passband, the maximum insertion loss is 0.43 dB. This indicates that the wide dual-passband filter based on topology 100 exhibits low insertion loss.

[0045] There are two transmission poles in the first passband, and the corresponding frequencies are f ep1 =2.8GHz, f op1 =3.6GHz; there are two transmission poles in the second passband, and the corresponding frequencies are f op2 =8.42GHz, f ep2 =9.1GHz. These four transmission poles ensure the flatness in the passband. There are three transmission zeros in the stopband, with the corresponding frequencies being f z1 =0,f z2 =5.94GHz, f z3 =10.82GHz, these three transmission zeros ensure high isolation of the wide dual-passband filter.

[0046] In the embodiment of the utility model, the double-passband filter comprises a substrate and a topology structure 100, the topology structure 100 is arranged on the substrate, and the topology structure 100 comprises an input end 10, a first parallel line 20, a first microstrip line 30, a second microstrip line 31, a third microstrip line 32, a fourth microstrip line 33, a first open-circuit branch 40, a second open-circuit branch 41 and an output end 50.

[0047] The utility model provides communication equipment embodiment, communication equipment includes above -mentioned double-passband filter, for the structure and function of double-passband filter can refer to above -mentioned embodiment, this place does not repeat again.

[0048] It should be noted that the specification and drawings of the utility model give the preferred embodiments of the utility model, however, the utility model can be realized through many different forms, and is not limited to the embodiments described in the specification, these embodiments are not as the additional limitation to the content of the utility model, and the purpose of providing these embodiments is to make the understanding of the disclosure of the utility model more thorough and comprehensive. Furthermore, the above technical features continue to combine, form various embodiments not listed above, which are considered to be within the scope of the utility model specification; further, for those skilled in the art, the above description can be improved or changed, and all these improvements and changes should be within the protection scope of the utility model claims.

Claims

1. A dual-passband filter, characterized in that: include: substrate; A topological structure is provided on the substrate, wherein the topological structure includes an input end, an output end, a first parallel line, a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a first open-circuit branch node, and a second open-circuit branch node; The input end is connected to one end of the first parallel line, the other end of the first parallel line is connected to the output end, the other end of the first parallel line, the first microstrip line, the second microstrip line and the first open branch are connected in sequence, and one end of the first parallel line, the third microstrip line, the fourth microstrip line and the second open branch are connected in sequence.

2. The dual-passband filter according to claim 1, wherein The first parallel lines include a first transmission line and a second transmission line arranged in parallel, one end of the first transmission line is connected to the input end, the other end of the first transmission line is connected to the first microstrip line, the second microstrip line and the first open branch in sequence, one end of the second transmission line is connected to the third microstrip line, the fourth microstrip line and the second open branch in sequence, and the other end of the second transmission line is connected to the output end.

3. The dual-passband filter according to claim 2, characterized in that , The first transmission line, the second transmission line, the second microstrip line and the fourth transmission line are all arranged in parallel and perpendicular to the first microstrip line, the third microstrip line, the first open branch and the second open branch.

4. The dual-passband filter according to claim 2, wherein , The electrical length of the first transmission line and the electrical length of the second transmission line are both one-quarter wavelength corresponding to the center frequency of the stopband between the two passbands, the sum of the electrical length of the first microstrip line, the electrical length of the second microstrip line and the electrical length of the first open branch is one-quarter wavelength corresponding to the center frequency of the stopband between the two passbands, and the sum of the electrical length of the third microstrip line, the electrical length of the fourth microstrip line and the electrical length of the second open branch is one-quarter wavelength corresponding to the center frequency of the stopband between the two passbands.

5. The dual-passband filter according to claim 2, characterized in that , Along a first direction, the length of the first open branch is less than the length of the first microstrip line, and the first transmission line, the first microstrip line, the second microstrip line, and the first open branch enclose a first cavity with a first opening; and / or Along the first direction, the length of the second open branch is less than the length of the third microstrip line, and the second transmission line, the third microstrip line, the fourth microstrip line, and the second open branch enclose a second cavity with a second opening; The first direction is the direction from the first transmission line to the second transmission line.

6. The dual-passband filter according to claim 5, characterized in that , Along the first direction, the distance between the first transmission line and the second transmission line is 0.1 mm; and / or, Along the first direction, the width of the first transmission line and the second transmission line are both 0.1 mm; and / or, Along the second direction, the lengths of the first transmission line and the second transmission line are both 8.2 mm; The second direction is perpendicular to the first direction.

7. The dual-passband filter according to claim 6, characterized in that , Along the first direction, the lengths of the first microstrip line and the third microstrip line are both 1.95 mm, and the widths of the second microstrip line and the fourth microstrip line are both 0.1 mm; and / or, Along the second direction, the lengths of the second microstrip line and the fourth microstrip line are both 4.9 mm, and the widths of the first microstrip line and the third microstrip line are both 0.1 mm.

8. The dual-passband filter according to claim 5, characterized in that , The other end of the first transmission line is spaced apart from the output end, and the second microstrip line extends away from the other end of the first microstrip line toward the input end, the first cavity is located between the input end and the output end, and the first opening is located on a side of the first cavity close to the input end; and / or, One end of the second transmission line is spaced apart from the input end, and the other end of the fourth microstrip line is away from the third microstrip line and extends toward the output end. The second cavity is located between the input end and the output end, and the second opening is located on a side of the second cavity close to the output end.

9. The dual-passband filter according to any one of claims 1 to 8, wherein: The characteristic impedance of the first microstrip line, the characteristic impedance of the second microstrip line, the characteristic impedance of the third microstrip line, the characteristic impedance of the fourth microstrip line, the characteristic impedance of the first open-circuit stub, and the characteristic impedance of the second open-circuit stub are all equal.

10. A communication device, characterized in that: The method comprises a dual-passband filter as claimed in any one of claims 1 to 9.

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