Topological structure, band-pass filter and communication equipment

Abstract

The embodiment of the utility model provides a topological structure, a band-pass filter and communication equipment. The topological structure comprises a first three parallel line, a second three parallel line, a first microstrip line, a second microstrip line, a first open-circuit branch, a second open-circuit branch, a variable capacitance diode, an input end and an output end. One end of the first parallel three-line is connected to one end of the second parallel three-line and one end of the first microstrip line, and the other end is connected to the input end; the other end of the second parallel three line is connected to the output end; one end of the second microstrip line is respectively connected to the first open-circuit branch knot and the second open-circuit branch knot; the variable capacitance diode is respectively connected to the other end of the first microstrip line and the other end of the second microstrip line; the first three parallel lines and the second three parallel lines are connected with the first microstrip line; the first open-circuit branch knot is connected with the second open-circuit branch knot. The band-pass filter designed based on the topological structure has the advantages of high selectivity, independent and continuous lower pass band edge adjustability and wide bandwidth tuning range.

Description

Technical Field

[0001] The utility model relates to the technical field of communication equipment, in particular to a topological structure, a bandpass filter and communication equipment. Background Art

[0002] At present, with the rapid development of modern 5G communication technology, the miniaturization of multifunctional communication systems has become an inevitable development trend. However, the reality is that the RF filters currently widely used in multifunctional communication systems have the characteristics of non-adjustable bandwidth and fixed functions. In order to realize the multifunctionality of the communication system, a large number of RF filters with different indicators need to be arranged inside the system, which will undoubtedly increase the complexity and volume of the communication system. If the RF filter has the ability to adjust the bandwidth, the same filter can flexibly meet different indicators, which will help simplify the design of the wireless communication system and greatly reduce its volume and weight. In addition, in order to make full use of spectrum resources, high selectivity is required in each microwave communication system.

[0003] However, the bandwidth-adjustable RF filters in the prior art often cannot simultaneously meet the requirements of independent and continuous adjustment of the lower passband edge, high selectivity and wide tuning range, which affects their use in modern high-speed information transmission communication systems. Utility Model Content

[0004] The topological structure, bandpass filter and communication equipment provided by the utility model are intended to solve at least a part of the defects of the existing bandpass filter with adjustable bandwidth.

[0005] In a first aspect, the utility model provides a topological structure. The topological structure includes:

[0006] A first parallel three-wire, a second parallel three-wire, a first microstrip line, a second microstrip line, a first open-circuit branch, a second open-circuit branch, a varactor diode, an input end, and an output end;

[0007] One end of the first parallel three-wire is respectively connected to one end of the second parallel three-wire and one end of the first microstrip line, and the other end is connected to the input end; the other end of the second parallel three-wire is connected to the output end; one end of the second microstrip line is respectively connected to the first open branch node and the second open branch node; the varactor diode is respectively connected to the other end of the first microstrip line and the other end of the second microstrip line;

[0008] The first parallel three lines and the second parallel three lines are both connected to the first microstrip line; the first open-circuit branch node and the second open-circuit branch node are connected to each other.

[0009] In some embodiments, the first three parallel lines, the second three parallel lines, the first open branch node, and the second open branch node are parallel to each other and perpendicular to the first microstrip line and the second microstrip line.

[0010] In some embodiments, the first parallel three lines and the second parallel three lines, the first open-circuit stub and the second open-circuit stub are symmetrical about the first microstrip line or the second microstrip line.

[0011] In some embodiments, the first microstrip line and the second microstrip line are symmetrical about the varactor diode.

[0012] In some embodiments, the electrical lengths of the first parallel three lines, the second parallel three lines, the first open-circuited branch, and the second open-circuited branch are equal, and are all one-quarter wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor is infinite.

[0013] In some embodiments, the electrical lengths of the first microstrip line and the second microstrip line are equal, and are both one-eighth of the wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor is infinite.

[0014] In some embodiments, the characteristic impedance of the first microstrip line is equal to the characteristic impedance of the second microstrip line; the characteristic impedance of the first open-circuit stub is equal to the characteristic impedance of the second open-circuit stub.

[0015] In some embodiments, the varactor has a variable capacitance; the equivalent electrical lengths of the first microstrip line and the second microstrip line change with the capacitance of the varactor, so that the lower passband edge of the bandpass filter based on the topological structure can be adjusted independently and continuously and the upper passband edge remains unchanged.

[0016] In a second aspect, the utility model provides a bandpass filter. The bandpass filter includes the above-mentioned topological structure.

[0017] In a third aspect, the utility model provides a communication device, wherein the communication device comprises the above-mentioned bandpass filter.

[0018] At least one beneficial effect of the embodiment of the utility model is that the bandpass filter designed based on the topological structure has the advantages of being able to simultaneously meet the requirements of high selectivity, independent and continuous adjustment of the lower passband edge, and a wide bandwidth tuning range. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] One or more embodiments are exemplarily described by corresponding drawings, which do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings represent similar elements, and the figures in the drawings do not constitute proportional limitations unless otherwise stated.

[0020] Figure 1 It is a schematic diagram of the topological structure provided by the embodiment of the utility model;

[0021] Figure 2 It is a first layout schematic diagram of an example of a bandpass filter designed based on a topological structure provided by an embodiment of the utility model;

[0022] Figure 3 It is a second layout schematic diagram of an example of a bandpass filter designed based on a topological structure provided in an embodiment of the utility model;

[0023] Figure 4 1 is an S parameter simulation result diagram of a bandpass filter example provided by an embodiment of the present utility model (I);

[0024] Figure 5 2 is an S parameter simulation result diagram of a bandpass filter example provided by an embodiment of the present utility model;

[0025] Figure 6 IS is the parameter of the bandpass filter example provided by the embodiment of the utility model 21 I simulation result diagram.

[0026] Figure numerals: 10, input end; 20, first three parallel lines; 21, second three parallel lines; 201, first transmission line; 202, second transmission line; 203, third transmission line; 211, fourth transmission line; 212, fifth transmission line; 213, sixth transmission line; 30, first microstrip line; 31, second microstrip line; 40, first open-circuit branch; 41, second open-circuit branch; 50, output end; 60, first soldering pad; 70, second soldering pad; 80, DC ground. DETAILED DESCRIPTION

[0027] The present invention is described in detail below in conjunction with specific embodiments. It should be emphasized that the following description is merely illustrative and is not intended to limit the scope and application of the present invention.

[0028] It should be noted that, unless otherwise clearly specified and limited, the terms "vertical", "parallel", etc. used in this specification indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the utility model. Terms such as "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium. In addition, the terms "first", "second", "third", "fourth", "fifth", and "sixth" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated; therefore, the features defined as "first", "second", "third", "fourth", "fifth", and "sixth" can explicitly or implicitly include one or more of the features; "multiple" or "several" means two or more; "and / or" includes any and all combinations of one or more related listed items. For those skilled in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0029] Figure 1 It is a schematic diagram of the topological structure provided by an embodiment of the utility model. Figure 2 It is a first layout schematic diagram of an example of a bandpass filter designed based on a topological structure provided in an embodiment of the utility model.

[0030] See also Figure 1 and Figure 2 The topological structure includes: a first parallel three-wire 20, a second parallel three-wire 21, a first microstrip line 30, a second microstrip line 31, a first open-circuit branch 40, a second open-circuit branch 41, a varactor diode D1, an input end 10 and an output end 50.

[0031] Among them, one end of the first parallel three-wire 20 is respectively connected to one end of the second parallel three-wire 21 and one end of the first microstrip line 30, and the other end is connected to the input end 10; the other end of the second parallel three-wire 21 is connected to the output end 50; one end of the second microstrip line 31 is respectively connected to the first open-circuit branch 40 and the second open-circuit branch 41; the varactor diode D1 is respectively connected to the other end of the first microstrip line 30 and the other end of the second microstrip line 31.

[0032] In addition, the first parallel three-line 20 and the second parallel three-line 21 are both connected to the first microstrip line 30; the first open-circuit branch 40 and the second open-circuit branch 41 are connected to each other.

[0033] In some embodiments, please refer to Figure 1 and Figure 2 The first parallel three lines 20 , the second parallel three lines 21 , the first open branch 40 and the second open branch 41 are parallel to each other and perpendicular to the first microstrip line 30 and the second microstrip line 31 .

[0034] In some embodiments, Figure 1 and Figure 2 As shown, the first parallel three lines 20 and the second parallel three lines 21 , the first open stub 40 and the second open stub 41 are all symmetrical with respect to the first microstrip line 30 or the second microstrip line 31 .

[0035] In some embodiments, in combination Figure 1 and Figure 2 It can be seen that the first microstrip line 30 and the second microstrip line 31 are symmetrical about the varactor diode D1 .

[0036] Figure 3 It is a second layout schematic diagram of an example of a bandpass filter designed based on a topological structure provided in an embodiment of the present utility model.

[0037] In some embodiments, Figure 1 to Figure 3 It can be seen that the electrical lengths of the first parallel three lines 20, the second parallel three lines 21, the first open branch 40 and the second open branch 41 are equal and are all a quarter wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor diode D1 is infinite.

[0038] In some embodiments, see Figure 1 to Figure 3 The electrical lengths of the first microstrip line 30 and the second microstrip line 31 are equal, and are both one-eighth of the wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor diode D1 is infinite.

[0039] In some embodiments, Figure 1 and Figure 2 As shown, the characteristic impedance of the first microstrip line 30 is equal to the characteristic impedance of the second microstrip line 31 ; the characteristic impedance of the first open-circuit stub 40 is equal to the characteristic impedance of the second open-circuit stub 41 .

[0040] In some embodiments, Figure 1 and Figure 2 As shown, the varactor diode D1 has a variable capacitance; the equivalent electrical lengths of the first microstrip line 30 and the second microstrip line 31 change with the capacitance of the varactor diode D1, so that the lower passband edge of the bandpass filter based on the topological structure can be adjusted independently and continuously and the upper passband edge remains unchanged.

[0041] In the embodiments of the present application, Figure 2 and Figure 3As shown, the bandpass filter based on the topological structure design may also include: a protective resistor R1, a first RF blocking inductor L1, a second RF blocking inductor L2, a first solder pad 60, a second solder pad 70, a DC ground 80 and a DC power supply; wherein, one end of the first RF blocking inductor L1 is connected to the first open branch 40, and the other end of the first RF blocking inductor L1 is connected to one end of the first solder pad 60; one end of the protective resistor R1 is connected to the other end of the first solder pad 60, and the other end of the protective resistor R1 is connected to the second solder pad 70; the second RF blocking inductor One end of L2 is connected to the first microstrip line 30, and the other end is connected to the DC ground 80; the DC power supply is connected to the second pad 70, and together with the protection resistor R1, the first pad 60, the first RF blocking inductor L1, the first open branch 40, the second microstrip line 31, the varactor D1, the first microstrip line 30, the second RF blocking inductor L2 and the DC ground 80, forms a DC loop for providing a DC voltage to the varactor D1; the DC power supply has different DC voltages so that the varactor D1 exhibits different capacitance values ​​under different voltages.

[0042] The utility model also provides a bandpass filter embodiment. In order to facilitate readers to understand the concept of the utility model, the following simulation experiment is performed on the actual object of the bandpass filter. The bandpass filter can be set on a circuit board; the size specifications of the circuit board are: the length dimension is 18.0mm, the width dimension is 9.5mm, and the thickness dimension is 0.813mm; the dielectric constant of the circuit board is 3.38, and the dielectric loss of the circuit board is 0.0022.

[0043] Combine 1 and Figure 3 It can be seen that the size parameter of the bandpass filter is: l P =6.8mm,s P =0.1mm, w P =0.2mm, l1=3.6mm, l2=3.6mm, l3=7.2mm, w1=0.6mm, w2=0.5mm.

[0044] Among them, l P is the physical length of the first three parallel lines 20 and the second three parallel lines 21; s P w is the distance between the first transmission line 201 and the second transmission line 202, the distance between the second transmission line 202 and the third transmission line 203, the distance between the fourth transmission line 211 and the fifth transmission line 212, and the distance between the fifth transmission line 212 and the sixth transmission line; Pare the physical widths of the first transmission line 201, the second transmission line 202, the third transmission line 203, the fourth transmission line 211, the fifth transmission line 212, and the sixth transmission line 213; l1 is the physical length of the first microstrip line 30; l2 is the physical length of the second microstrip line 31; l3 is the physical length of the first open branch 40 and the physical length of the second open branch 41; w1 is the physical width of the first microstrip line 30 and the physical width of the second microstrip line 31; w2 is the physical width of the first open branch 40 and the physical width of the second open branch 41.

[0045] Figure 4 1 is a diagram of S-parameter simulation results of a bandpass filter example provided by an embodiment of the present utility model.

[0046] The simulation results of the bandpass filter of the utility model in state 1 are as follows: Figure 4 As shown (in state 1, the capacitance corresponding to the varactor diode D1 is 0.6pF), the impedance bandwidth range of the bandpass filter with a reflection coefficient less than -10dB is 6.818GHz to 10.446GHz, the passband center frequency is 8.632GHz, the absolute bandwidth of the passband is 3.628GHz, and the relative bandwidth of the passband is 42%; wherein, there are two transmission poles in the passband, located at 8.602GHz and 10.25GHz respectively, which can ensure the flatness within the band; there are two transmission zeros in the stopband, located at 4.5GHz and 11.2GHz respectively, which can ensure the high selectivity of the bandpass filter.

[0047] Figure 5 This is the S parameter simulation result diagram (2) of the bandpass filter example provided by the embodiment of the utility model.

[0048] The simulation results of the bandpass filter of the utility model in state 2 are as follows: Figure 5 As shown (in state 2, the capacitance corresponding to the varactor diode D1 is 32pF), the impedance bandwidth range of the bandpass filter with a reflection coefficient less than -10dB is 3.753GHz to 10.437GHz, the passband center frequency is 7.095GHz, the absolute bandwidth of the passband is 6.684GHz, and the relative bandwidth of the passband is 94.2%; wherein, there are five transmission poles in the passband, located at 3.95GHz, 4.94GHz, 8.03GHz, 8.88GHz and 10.25Hz, respectively, to ensure the flatness within the band; there are two transmission zeros in the stopband, located at 2.91GHz and 11.13GHz, respectively, to ensure the high selectivity of the bandpass filter.

[0049] Depend on Figure 3 and Figure 4It can be seen that the bandpass filter designed based on this topological structure can increase the relative bandwidth of its passband from 42% to 94.2% when the capacitance of the varactor diode D1 increases from 0.6pF to 32pF, and has high selectivity characteristics in both state 1 and state 2; therefore, the bandpass filter designed based on this topological structure has the advantages of high selectivity and a wide bandwidth tuning range.

[0050] Figure 6 IS is the parameter of the bandpass filter example provided by the embodiment of the utility model 21 I simulation result diagram (iii).

[0051] Figure 6 The parameter IS in state 1 and state 2 is given 21 I simulation results (in Figure 6 In the figure, the solid line represents the parameter IS in state 1. 21 I simulation results, the dotted line represents the parameter IS in state 2 21 I simulation results).

[0052] Depend on Figure 6 It can be seen that as the capacitance of the varactor diode D1 increases (for example, the capacitance of the varactor diode D1 increases from 0.6 pF in state 1 to 32 pF in state 2), the lower passband edge of the bandpass filter moves downward, and its upper passband edge remains unchanged. Therefore, the bandpass filter designed based on this topological structure has the characteristic that the lower passband edge can be adjusted separately.

[0053] The utility model also provides a communication device embodiment. The communication device includes: the above-mentioned bandpass filter; the structure and function of the bandpass filter can be referred to the above-mentioned embodiment, and will not be described one by one here.

[0054] In summary, the topological structure, bandpass filter and communication device provided by the embodiment of the utility model have the advantages of being able to simultaneously meet the requirements of high selectivity, continuous adjustment of the lower passband edge, and wide bandwidth tuning range. Therefore, the topological structure, bandpass filter and communication device provided by the embodiment of the utility model have certain novelty compared with the traditional topological structure, bandpass filter and communication device.

[0055] The above contents are further detailed descriptions of the present invention in combination with specific / preferred implementations, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A topological structure, characterized in that: include: A first parallel three-wire, a second parallel three-wire, a first microstrip line, a second microstrip line, a first open-circuit branch, a second open-circuit branch, a varactor diode, an input end, and an output end; One end of the first parallel three-wire is respectively connected to one end of the second parallel three-wire and one end of the first microstrip line, and the other end is connected to the input end; the other end of the second parallel three-wire is connected to the output end; one end of the second microstrip line is respectively connected to the first open branch node and the second open branch node; the varactor diode is respectively connected to the other end of the first microstrip line and the other end of the second microstrip line; The first parallel three lines and the second parallel three lines are both connected to the first microstrip line; the first open-circuit branch node and the second open-circuit branch node are connected to each other.

2. The topological structure according to claim 1, characterized in that: The first three parallel lines, the second three parallel lines, the first open branch node and the second open branch node are parallel to each other and perpendicular to the first microstrip line and the second microstrip line.

3. The topological structure according to claim 1, characterized in that: The first parallel three lines and the second parallel three lines, the first open branch and the second open branch are all symmetrical about the first microstrip line or the second microstrip line.

4. The topological structure according to claim 1, characterized in that: The first microstrip line and the second microstrip line are symmetrical about the varactor diode.

5. The topological structure according to claim 1, characterized in that: The electrical lengths of the first parallel three lines, the second parallel three lines, the first open branch, and the second open branch are equal, and are all a quarter wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor is infinite.

6. The topological structure according to claim 1, characterized in that: The electrical lengths of the first microstrip line and the second microstrip line are equal, and are both one eighth of the wavelength corresponding to the center frequency of the bandpass filter based on the topological structure when the capacitance of the varactor diode is infinite.

7. The topological structure according to claim 1, characterized in that: The characteristic impedance of the first microstrip line is equal to the characteristic impedance of the second microstrip line; the characteristic impedance of the first open-circuit branch is equal to the characteristic impedance of the second open-circuit branch.

8. The topological structure according to claim 1, characterized in that: The varactor has a variable capacitance; the equivalent electrical lengths of the first microstrip line and the second microstrip line change with the capacitance of the varactor, so that the lower passband edge of the bandpass filter based on the topological structure can be adjusted independently and continuously and the upper passband edge remains unchanged.

9. A bandpass filter, characterized in that: include: A topological structure as claimed in any one of claims 1 to 8.

10. A communication device, characterized in that: include: The bandpass filter as claimed in claim 9.

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