Topological structure, wide dual-passband filter and communication equipment

Abstract

The embodiment of the utility model relates to the technical field of communication equipment, and particularly discloses a topological structure, a wide dual-passband filter and communication equipment, which comprise 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, one end of the first parallel line is connected with one end of the first microstrip line and one end of the third microstrip line, the other end of the first microstrip line is connected with the input end, the other end of the third microstrip line is connected with the second open-circuit branch knot, and the other end of the first parallel line is connected with one end of the second microstrip line and one end of the fourth microstrip line. The other end of the second microstrip line is connected with the first open-circuit branch knot, and the other end of the fourth microstrip line is connected with the output end. Through the above mode, the embodiment of the utility model can obtain a miniaturized wide dual-passband filter based on the above topological structure design.

Description

Technical Field

[0001] The embodiments of the utility model relate to the technical field of topological structures, and in particular to a topological structure, a wide dual-passband filter and a communication device. Background Art

[0002] With the rapid development of modern wireless communication technology, people's demand for broadband communication systems that can achieve high-speed data transmission is increasing, and it has become the focus of research by practitioners in related fields. Micro-bandwidth dual-passband filters with low cost, light weight, low profile and easy integration have attracted the attention of many scholars and engineers and have been deeply studied.

[0003] During the process of realizing the present invention, the inventors discovered that, in order to ensure that signals are allowed to pass through within two relatively wide frequency ranges while suppressing signals of other frequencies, most current wide dual-passband filters have complicated circuit structures, resulting in large sizes of the wide dual-passband filters, which seriously affects their use in modern high-speed information transmission communication systems. Utility Model Content

[0004] The embodiments of the utility model provide a topology structure, a wide dual-passband filter and a communication device, which mainly solve the technical problem that the wide dual-passband filter is too large in size.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: providing a topological structure including 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, one end of the first parallel line is respectively connected to one end of the first microstrip line and one end of the third microstrip line, the other end of the first microstrip line is connected to the input end, the other end of the third microstrip line is connected to the second open branch, the other end of the first parallel line is respectively connected to one end of the second microstrip line and one end of the fourth microstrip line, the other end of the second microstrip line is connected to the first open branch, and the other end of the fourth microstrip line is connected to the output end.

[0006] Optionally, the first microstrip line, the fourth microstrip line, the first open branch, the second open branch and the first parallel line are all arranged in parallel.

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

[0008] Optionally, the first parallel lines include a first transmission line and a second transmission line, and the first transmission line and the second transmission line are arranged in parallel; wherein the first transmission line, the second transmission line, the first microstrip line, the fourth microstrip line, the first open branch and the second open branch are parallel to each other and are perpendicular to the second microstrip line and the third microstrip line.

[0009] Optionally, the electrical length of the first transmission line is equal to the electrical length of the second transmission line; the electrical length of the first microstrip line is equal to the electrical length of the fourth microstrip line; the electrical length of the second microstrip line is equal to the electrical length of the third microstrip line; the electrical length of the first open branch is equal to the electrical length of the second open branch; wherein 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 equal to the electrical length of the first transmission line.

[0010] Optionally, the electrical length of the first transmission line and the electrical length of the second transmission line are both a quarter wavelength corresponding to a center frequency of a stop band between two pass bands.

[0011] Optionally, the electrical length of the first transmission line and the electrical length of the second transmission line are a quarter wavelength corresponding to a center frequency of a stop band between two pass bands.

[0012] 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.

[0013] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a wide dual-passband filter obtained by the above topological structure design.

[0014] In order to solve the above technical problems, another technical solution adopted by the present invention is to provide a communication device, including the above wide dual-passband filter

[0015] The beneficial effects of the embodiment of the present utility model are as follows: Different from the prior art, the embodiment of the present utility model provides a topology structure including 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, one end of the first parallel line is respectively connected to one end of the first microstrip line and one end of the third microstrip line, the other end of the first microstrip line is connected to the input end, the other end of the third microstrip line is connected to the second open-circuit branch, the other end of the first parallel line is respectively connected to one end of the second microstrip line and one end of the fourth microstrip line, the other end of the second microstrip line is connected to the first open-circuit branch, and the other end of the fourth microstrip line is connected to the input end. The wide dual-passband filter designed based on the above topology structure has four transmission poles to ensure flatness within the passband, and also has three transmission zeros to ensure high isolation of the wide dual-passband filter, thereby making the wide dual-passband filter have the advantage of miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0017] Figure 1 It is a schematic diagram of the topological structure provided by an embodiment of the present utility model;

[0018] Figure 2 Schematic diagram of the layout of a wide dual-passband filter obtained based on topological structure design provided by an embodiment of the present invention;

[0019] Figure 3 This is a labeled diagram of the layout of a wide dual-passband filter obtained based on the topological structure design provided by an embodiment of the present invention;

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

[0021] Figure 5 This is a schematic diagram of the topological structure of the even mode provided by the embodiment of the present utility model;

[0022] Figure 6 This is a diagram of S-parameter simulation results of a wide dual-passband filter obtained based on topological structure design provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] 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.

[0024] 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.

[0025] See also Figure 1 The topology structure 100 includes an input end 10, an output end 50, a first parallel line 30, a first microstrip line 20, a second microstrip line 21, a third microstrip line 22, a fourth microstrip line 23, a first open branch 40 and a second open branch 41; wherein, one end of the first parallel line 30 is respectively connected to one end of the first microstrip line 20 and one end of the third microstrip line 22, the other end of the first microstrip line 20 is connected to the input end 10, the other end of the third microstrip line 22 is connected to the second open branch 41, the other end of the first parallel line 30 is respectively connected to one end of the second microstrip line 21 and one end of the fourth microstrip line 23, the other end of the second microstrip line 21 is connected to the first open branch 40, and the other end of the fourth microstrip line 23 is connected to the output end 50.

[0026] In some embodiments, the first microstrip line 20 , the fourth microstrip line 23 , the first open stub 40 , the second open stub 41 and the first parallel line 30 are all arranged in parallel.

[0027] In some embodiments, the first microstrip line 20 , the fourth microstrip line 23 , the first open stub 40 , the second open stub 41 and the first parallel line 30 are all perpendicular to the second microstrip line 21 and the third microstrip line 22 .

[0028] In some embodiments, the first parallel line 30 comprises a first transmission line 301 and a second transmission line 302, the first transmission line 301 and the second transmission line 302 are arranged in parallel; wherein the first transmission line 301, the second transmission line 302, the first microstrip line 20, the fourth microstrip line 23, the first open stub 40 and the second open stub 41 are parallel to each other, and are perpendicular to the second microstrip line 21 and the third microstrip line 22.

[0029] In some embodiments, the electrical length of the first transmission line 301 and the electrical length of the second transmission line 302 are equal.

[0030] The electrical length of the first microstrip line 20 and the electrical length of the fourth microstrip line 23 are equal.

[0031] The electrical length of the second microstrip line 21 and the electrical length of the third microstrip line 22 are equal.

[0032] The electrical length of the first open stub 40 and the electrical length of the second open stub 41 are equal.

[0033] The sum of the electrical length of the first microstrip line 20, the electrical length of the second microstrip line 21 and the electrical length of the first open stub 40 is equal to the electrical length of the first transmission line 301.

[0034] Specifically, the electrical length of the first transmission line 301 and the electrical length of the second transmission line 302 are both a quarter of the wavelength corresponding to the center frequency of the stop band between the two pass bands. The electrical length of the first transmission line 301 and the electrical length of the second transmission line 302 are a quarter of the wavelength corresponding to the center frequency of the stop band between the two pass bands.

[0035] In some embodiments, the characteristic impedance of the first microstrip line 20, the characteristic impedance of the second microstrip line 21, the characteristic impedance of the third microstrip line 22, the characteristic impedance of the fourth microstrip line 23, the characteristic impedance of the first open stub 40 and the characteristic impedance of the second open stub 41 are equal.

[0036] Further, the odd mode characteristic impedance of the first parallel line 30 composed of the first transmission line 301 and the second transmission line 302 is Z oo , and the even mode characteristic impedance is Z oe ; the characteristic impedance of the first microstrip line 20, the characteristic impedance of the second microstrip line 21, the characteristic impedance of the third microstrip line 22, the characteristic impedance of the fourth microstrip line 23, the characteristic impedance of the first open stub 40 and the characteristic impedance of the second open stub 41 are equal, and are all Z1.

[0037] The utility model provides a topology structure 100, comprising an input terminal 10, an output terminal 50, a first parallel line 30, a first microstrip line 20, a second microstrip line 21, a third microstrip line 22, a fourth microstrip line 23, a first open branch 40, and a second open branch 41; wherein one end of the first parallel line 30 is respectively connected to one end of the first microstrip line 20 and one end of the third microstrip line 22, the other end of the first microstrip line 20 is respectively connected to the input terminal 10, the other end of the third microstrip line 22 is connected to the second open branch 41, the other end of the first parallel line 30 is respectively connected to one end of the second microstrip line 21 and one end of the fourth microstrip line 23, the other end of the second microstrip line 21 is connected to the first open branch 40, and the other end of the fourth microstrip line 23 is connected to the output terminal 50. In this manner, a wide dual-passband filter designed based on this topology structure 100 has the characteristic of miniaturization.

[0038] The present invention further provides an embodiment of a wide dual-passband filter, which includes the above-mentioned topological structure 100. The specific structure and function of the above-mentioned topological structure 100 can be found in the above-mentioned embodiment and will not be described in detail here.

[0039] To facilitate the reader's understanding, the following provides ideas for designing a wide dual-passband filter with miniaturization characteristics based on the above topology 100. Figures 2 to 5 , as follows:

[0040] Since the topology 100 is equivalent to a symmetrical structure, its transmission poles can be obtained by odd-even mode analysis. In order to more easily calculate the transmission poles of the topology 100, it is first assumed that the sum of the electrical length of the second microstrip line 21 and the electrical length of the first open branch 40 is much greater than the electrical length of the first microstrip line 20. In this case, the odd-mode form of the topology 100 is as follows: Figure 4 As shown, the electrical length of the odd-mode transmission line is a quarter wavelength corresponding to the stopband center frequency between the two passbands, and the characteristic impedance of the odd-mode transmission line is Z oo .

[0041] When Y ino = 0, it can be concluded that the topology 100 has two transmission poles. When f0 is the center frequency of the stop band between the two pass bands, the frequencies corresponding to the two odd-mode transmission poles are:

[0042]

[0043] The even mode form of the topology 100 is as follows Figure 5 As shown, the electrical length of the even-mode transmission line is a quarter wavelength corresponding to the stopband center frequency between the two passbands, and the characteristic impedance of the even-mode transmission line is Z oe.

[0044] When Y ine = 0, it can be concluded that the topology 100 has two even-mode transmission poles. When f0 is the center frequency of the stop band between the two pass bands, the frequencies corresponding to the two even-mode transmission poles are:

[0045]

[0046] For this topology 100, its transmission zero point can be calculated by the following formula:

[0047]

[0048] After calculation, it can be concluded that the topology structure 100 has three transmission zeros, and the frequencies corresponding to the three transmission zeros are:

[0049] f z1 =0

[0050] f z2 =f0

[0051] f z3 =2f0

[0052] From the above analysis, it can be seen that the filter based on the topology 100 has two odd-mode transmission poles, three even-mode transmission poles and three transmission zeros. oo , Z oe and the value of Z1, the relative position of the transmission zero pole, that is, f z1 <f ep1 <f op1 <f2<f op2 <f ep2 <f z3 , will not change. Therefore, based on this topology 100, a dual-passband filter can be designed with two transmission poles in each of the two passbands to ensure in-band flatness, a transmission zero below the first passband edge and above the fourth passband edge to ensure high selectivity, and a transmission zero between the second and third passband edges to ensure high isolation. Therefore, the filter designed based on this topology 100 is a miniaturized wide dual-passband filter.

[0053] To verify the above theory, a dual-passband filter example based on the topological structure 100 is provided. The topological structure 100 is arranged on a circuit board (not shown). The circuit board (not shown) has a dielectric constant of 3.38, a dielectric loss of 0.0022, a thickness of 0.813 mm, and a size of 12.8 mm*2.8 mm. Figure 2 and Figure 3As shown, the size parameters are set as: l P =6.65mm,s P =0.1mm,w P =0.15mm, l1=1.2mm, l2=0.85mm, l3=4.8mm, w1=0.15mm.

[0054] Among them, l P represents the physical length of the first parallel line 30, s P represents the distance between the first transmission line 301 and the second transmission line 302, w P represents the physical width of the first transmission line 301 and the physical width of the second transmission line 302, l1 represents the physical length of the first microstrip line 20 or the physical length of the fourth microstrip line 23, l2 represents the physical length of the second microstrip line 21 or the physical length of the third microstrip line 22, l3 represents the physical length of the first open branch 40 or the physical length of the second open branch 41, w1 represents the physical width of the first microstrip line 20 or the physical width of the second microstrip line 21 or the physical width of the third microstrip line 22 or the physical width of the fourth microstrip line 23 or the physical width of the first open branch 40 or the physical width of the second open branch 41.

[0055] The simulation results of the wide dual-passband filter are as follows Figure 6 As shown. Figure 6 It can be seen that within the first passband, the impedance bandwidth with a reflection coefficient less than -10dB ranges from 3.164GHz to 5.048GHz, the passband center frequency is 4.106GHz, the passband absolute bandwidth is 1.884GHz, and the passband relative bandwidth is 45.9%. Within the second passband, the impedance bandwidth with a reflection coefficient less than -10dB ranges from 10.092GHz to 11.456GHz, the passband center frequency is 10.774GHz, the passband absolute bandwidth is 1.364GHz, and the passband relative bandwidth is 12.7%. Bandwidth simulations of these two passbands indicate that the dual-passband filter based on topology 100 is a wide dual-passband filter. Within the first passband, the maximum insertion loss is 0.48dB; within the second passband, the maximum insertion loss is 0.63dB. Therefore, the wide dual-passband filter based on topology 100 has low insertion loss characteristics.

[0056] In addition, there are two transmission poles in the first passband, located at 3.628 GHz and 4.524 GHz, and two transmission poles in the second passband, located at 10.431 GHz and 11.119 GHz. These four transmission poles ensure passband flatness.

[0057] There are three transmission zeros in the stopband, located at 0, 7.902 GHz, and 15.413 GHz. These three transmission zeros ensure high isolation of the wide dual-passband filter.

[0058] Through the simulation example of the above topology structure 100 , it can be proved that the wide dual-passband filter designed based on the above topology structure 100 has the characteristic of miniaturization.

[0059] The present invention also provides an embodiment of a communication device, which includes the wide dual-passband filter. The specific structure and function of the wide dual-passband filter can be found in the above embodiments, which will not be described in detail here.

[0060] It should be noted that the preferred embodiments of the present invention are given in the specification and drawings of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described in this specification. These embodiments do not serve as additional limitations on the content of the present invention. The purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive. In addition, the above-mentioned technical features continue to be combined with each other to form various embodiments not listed above, which are all considered to be within the scope of the description of the present invention; further, it is obvious to those skilled in the art that improvements or changes can be made based on the above description, and all such improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A topological structure, characterized in that: include 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; Among them, one end of the first parallel line is respectively connected to one end of the first microstrip line and one end of the third microstrip line, the other end of the first microstrip line is connected to the input end, the other end of the third microstrip line is connected to the second open branch, the other end of the first parallel line is respectively connected to one end of the second microstrip line and one end of the fourth microstrip line, the other end of the second microstrip line is connected to the first open branch, and the other end of the fourth microstrip line is connected to the output end.

2. The topological structure according to claim 1, characterized in that: The first microstrip line, the fourth microstrip line, the first open branch, the second open branch and the first parallel line are all arranged in parallel.

3. The topological structure according to claim 2, characterized in that: The first microstrip line, the fourth microstrip line, the first open branch, the second open branch, and the first parallel line are all perpendicular to the second microstrip line and the third microstrip line.

4. The topological structure according to claim 1, characterized in that: The first parallel lines include a first transmission line and a second transmission line, and the first transmission line and the second transmission line are arranged in parallel; The first transmission line, the second transmission line, the first microstrip line, the fourth microstrip line, the first open branch and the second open branch are parallel to each other and perpendicular to the second microstrip line and the third microstrip line.

5. The topological structure according to claim 4, characterized in that: The electrical length of the first transmission line is equal to the electrical length of the second transmission line; The electrical length of the first microstrip line is equal to the electrical length of the fourth microstrip line; The electrical length of the second microstrip line is equal to the electrical length of the third microstrip line; The electrical length of the first open branch is equal to the electrical length of the second open branch; 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 equal to the electrical length of the first transmission line.

6. The topological structure according to claim 5, characterized in that: The electrical length of the first transmission line and the electrical length of the second transmission line are both a quarter wavelength corresponding to the center frequency of the stop band between the two pass bands.

7. The topological structure according to claim 5, characterized in that: The electrical length of the first transmission line and the electrical length of the second transmission line are a quarter wavelength corresponding to a center frequency of a stop band between two pass bands.

8. The topological structure according to claim 5, characterized in that: 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.

9. A wide dual-passband filter, characterized in that The topological structure is obtained by designing the topology according to any one of claims 1 to 8.

10. A communication device comprising the wide dual-passband filter according to claim 9.

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