CN113067561A - Band-stop filter and multi-frequency band-stop filter - Google Patents
Band-stop filter and multi-frequency band-stop filter Download PDFInfo
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- 238000010897 surface acoustic wave method Methods 0.000 claims description 8
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/64—Filters using surface acoustic waves
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
- H03H9/205—Constructional features of resonators consisting of piezoelectric or electrostrictive material having multiple resonators
Abstract
The embodiment of the invention discloses a band elimination filter and a multi-frequency band elimination filter. It comprises at least one band-stop filtering unit; the band elimination filter unit comprises an input port, an output port, at least two resonators and at least one inductive element; wherein the at least two resonators include at least one first resonator and at least one second resonator; the first end of the first resonator is connected between the input port and the inductive element, the second end of the first resonator is connected with the first fixed potential end, the first end of the second resonator is connected between the output port and the inductive element, and the second end of the second resonator is connected with the second fixed potential end. The invention can not only design proper stop band bandwidth in the working range of the inductive element according to the resonance frequency of the resonator, but also reduce the circuit size of the band-stop filter, improve the suppression effect on signals in the stop band range and reduce the loss of transmission signals in the working frequency range of the inductive element and outside the stop band range.
Description
Technical Field
The embodiment of the invention relates to the technical field of communication, in particular to a band rejection filter and a multi-frequency band rejection filter.
Background
With the development of communication technology, the requirement on the frequency spectrum utilization rate is higher and higher, and then the transmission frequency band distance between different information in the information transmission process is smaller and smaller. Therefore, the band-stop filter is required to pass the transmission signals in a specific frequency range and filter the noise spectrum or the spectrum without the transmission signals so as to meet the requirement of information transmission.
At present, designers usually adopt lumped elements such as capacitors and inductors to form a band-stop filter or adopt microstrip line circuits to form the band-stop filter, but the circuit design size of the two band-stop filters is too large to meet the application requirements of small portable equipment. In addition, a band-stop filter formed by lumped elements such as a capacitor and an inductor or a band-stop filter formed by a microstrip line circuit has a low quality factor, and has a poor effect of suppressing a spectrum in a stop band range.
Disclosure of Invention
The embodiment of the invention provides a band elimination filter and a multi-frequency band elimination filter, which aim to overcome the defect that the circuit size of the band elimination filter in the prior art is large, so that the application requirements of small-sized portable equipment can be met, and the suppression effect on signals in a stop band range is improved.
In a first aspect, an embodiment of the present invention provides a band-stop filter, including at least one band-stop filtering unit; the band elimination filter unit comprises an input port, an output port, at least two resonators and at least one inductive element; wherein the at least two resonators include at least one first resonator and at least one second resonator; the first end of the first resonator is connected between the input port and the inductive element, the second end of the first resonator is connected with the first fixed potential end, the first end of the second resonator is connected between the output port and the inductive element, and the second end of the second resonator is connected with the second fixed potential end.
Further, the band-elimination filter unit comprises a first resonator, a second resonator and an inductive element; the first end of the first resonator is connected between the input port and the first end of the inductive element, the second end of the first resonator is connected with the first fixed potential end, the first end of the second resonator is connected between the output port and the second end of the inductive element, and the second end of the second resonator is connected with the second fixed potential end.
Further, the difference between the resonant frequency of the first resonator and the resonant frequency of the second resonator is greater than zero and less than or equal to the stop band bandwidth of the second resonator or the first resonator.
Further, the maximum operating frequency of the inductive element is larger than the stop band frequencies of the first resonator and the second resonator.
Further, the band-stop filter comprises at least two band-stop filtering units; the difference of the resonant frequencies of the adjacent band-stop filtering units is larger than zero and smaller than or equal to the stopband bandwidth of one of the band-stop filtering units.
Further, the inductive element comprises an inductive element; the first end of the inductive element is used as the first end of the inductive element, and the second end of the inductive element is used as the second end of the inductive element.
Further, the resonator includes one or more of a surface acoustic wave resonator, a bulk acoustic wave resonator, and a thin film cavity acoustic resonator.
In a second aspect, an embodiment of the present invention further provides a multi-band-stop filter, including any one of the band-stop filters in the first aspect, where at least two band-stop filters are connected in series; the difference of the resonant frequencies of the at least two band-stop filters is larger than the stop band bandwidth of one of the band-stop filter units.
Further, the number of band-stop filtering units in different band-stop filters is the same or different.
According to the technical scheme of the embodiment of the invention, the band elimination filter comprises at least one band elimination filtering unit. Wherein the band-stop filtering unit comprises at least one first resonator, at least one inductive element and at least one second resonator having different resonance frequency characteristics. According to the characteristic that the pass-through resistance of the inductive element is high, the working frequency range of the band elimination filter can be limited, namely the difference loss of transmission signals passing through the working frequency range of the inductive element is small. The two ends of the inductive element are respectively connected with the first acoustic wave resonator and the second acoustic wave resonator, so that the inductive element can generate a stop band in a working range, and further, the filtering of the frequency in the stop band range is realized. In addition, the at least one first resonator and the at least one second resonator can adjust the overlapping range of the resonant frequency of the at least one first resonator and the at least one second resonator according to the requirement of the stop-band bandwidth of the band-stop filtering unit, so that the stop-band bandwidth of the band-stop filtering unit can be improved. In summary, the first resonator and the second resonator are adopted, and the first ends of the first resonator and the second resonator are respectively connected to the two ends of the inductive element, so that not only can an appropriate stop band bandwidth be designed within the working range of the inductive element according to the resonant frequency of the resonators, but also the circuit size of the band-stop filter can be reduced, the suppression effect on signals within the stop band range is improved, and the loss on transmission signals within the working frequency range of the inductive element and outside the stop band range is reduced.
Drawings
To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief description will be given below of the drawings required for the embodiments or the technical solutions in the prior art, and it is obvious that the drawings in the following description, although being some specific embodiments of the present invention, can be extended and extended to other structures and drawings by those skilled in the art according to the basic concepts of the device structure, the driving method and the manufacturing method disclosed and suggested by the various embodiments of the present invention, without making sure that these should be within the scope of the claims of the present invention.
Fig. 1 is a schematic structural diagram of a band-stop filter according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating the performance of a single resonator according to an embodiment of the present invention;
fig. 3 is a schematic performance diagram of a band stop filter according to an embodiment of the present invention;
fig. 4 is a schematic structural diagram of another band-stop filter provided in the embodiment of the present invention;
fig. 5 is a performance diagram of the band-stop filter of fig. 4 according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a multi-band rejection filter according to an embodiment of the present invention;
fig. 7 is a schematic structural diagram of another multi-band rejection filter according to an embodiment of the present invention;
fig. 8 is a schematic performance diagram of the multi-band rejection filter of fig. 7 according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The embodiment of the invention provides a structural schematic diagram of a band-stop filter, and fig. 1 is the structural schematic diagram of the band-stop filter provided by the embodiment of the invention. As shown in fig. 1, the band-stop filter includes at least one band-stop filtering unit; the band elimination filter unit comprises an input port A, an output port B, at least two resonators and at least one inductive element 110; wherein the at least two resonators include at least one first resonator 120 and at least one second resonator 130; the first end of the first resonator 120 is connected between the input port a and the inductive element 110, the second end of the first resonator 120 is connected to the first fixed potential end, the first end of the second resonator 130 is connected between the output port B and the inductive element 110, and the second end of the second resonator 130 is connected to the second fixed potential end.
Specifically, the band-stop filtering unit is a band-stop filter which can pass most frequency components, but attenuates the frequency components of a certain frequency band to an extremely low level to prevent the frequency components of the certain frequency band from passing through. The resonator has high quality factor, can generate resonant frequency, and the generated resonant frequency has the characteristics of strong stability and strong anti-interference performance. The inductive element 110 has a characteristic of high pass-through resistance, which can limit the operating frequency range of the band-stop filter, i.e. the difference loss of the passing transmission signal in the operating frequency range of the inductive element 110 is small. The first acoustic wave resonator 120 and the second acoustic wave resonator 130 are respectively connected to two ends of the inductive element 110, so that the inductive element 110 can generate a stop band within a working range, and further, filtering of frequencies within the stop band range is achieved. Fig. 2 is a performance diagram of a single resonator according to an embodiment of the present invention, where the abscissa is the frequency of the resonator and the ordinate is the interpolation loss of the signal. Curve 200 is the performance curve for a single resonator. As can be taken from fig. 2, a single resonator has a filter characteristic in response to itself. Fig. 3 is a performance diagram of a band-stop filter according to an embodiment of the present invention, wherein the band-stop filter includes a band-stop filtering unit, and the filtering unit includes a first resonator 120, a second resonator 130, and an inductive element 110. As shown in fig. 3, the abscissa is the frequency of the band-stop filter and the ordinate is the interpolation loss of the signal. Curve 300 is the performance curve of the band stop filter. As can be seen from fig. 3, the inductive element 110 may enable the band-stop filter to have a filtering characteristic with low frequency difference loss. For example, as shown in FIG. 3, the inductive element 110 may cause the band-stop filter to have a filter characteristic with very low differential loss in the range of 0-4 GHz. On the basis, the invention designs the band-stop filtering unit to comprise at least two resonators based on the filtering characteristic of the resonators to the response of the resonators. The first resonator 120 includes at least one resonator, a first end of the first resonator 120 is connected between the input port a and the inductive element 110, and a second end of the first resonator 120 is connected to the first fixed potential end. The second resonator 130 includes at least one resonator having a different resonance frequency characteristic from the first resonator 120, a first end of the second resonator 130 is connected between the output port B and the inductive element 110, and a second end of the second resonator 130 is connected to a second fixed potential end. The overlapping range of the resonant frequencies of the at least one first resonator 120 and the at least one second resonator 130 can be adjusted according to the requirement of the stop-band bandwidth of the band-stop filter, so that the stop-band bandwidth of the band-stop filter unit can be increased. The first fixed potential terminal and the second fixed potential terminal may be equal in potential, for example, the first fixed potential terminal and the second fixed potential terminal are commonly grounded. Comparing fig. 2 and fig. 3, the stopband frequency range of the single resonator of fig. 2 is smaller than the stopband frequency range of the bandstop filter of fig. 3. The differential loss of the single resonator of fig. 2 is less than that of the band-stop filter of fig. 3. Thus, by using the first resonator 120 and the second resonator 130 and connecting the first ends of the first resonator 120 and the second resonator 130 to the two ends of the inductive element 110, the characteristics of narrow bandwidth of the single resonator and poor signal rejection characteristics in the stop band range can be improved. Continuing with the comparison of fig. 2 and 3, the single resonator of fig. 2 produces a larger differential loss for low frequency signals than the band stop filter of fig. 3 produces for low frequency signals. In fig. 3, the inductive element 110 limits the operating frequency range to 0-4GHZ, that is, the inductive element 110 allows frequencies in the range of 0-4GHZ to pass, and the inductive element 110 blocks the frequency band larger than 4GHZ from passing. The two ends of the inductive element 110 are respectively connected to the first acoustic wave resonator 120 and the second acoustic wave resonator 130, so that the inductive element 110 generates a stop band within the working range, and the first acoustic wave resonator 120 and the second acoustic wave resonator 130 filter frequencies within the stop band. It is noted here that the resonance frequency of the first resonator 120 and the second resonator 130 needs to be set within the operating frequency range of the inductive element 110. In summary, the band-stop filtering unit formed by at least two resonators and at least one inductive element 110 according to the present invention can not only design a suitable stop band bandwidth within the working range of the inductive element 110 according to the resonant frequency of the resonators, but also reduce the circuit size of the band-stop filter, improve the suppression effect on signals within the stop band range, and reduce the loss of transmission signals within the working frequency range of the inductive element 110 and outside the stop band range.
Illustratively, with continued reference to fig. 1, the band-reject filter unit comprises one first resonator 120, one second resonator 130 and one inductive element 110; the first end of the first resonator 120 is connected between the input port a and the first end of the inductive element 110, the second end of the first resonator 120 is connected to the first fixed potential end, the first end of the second resonator 130 is connected between the output port B and the second end of the inductive element 110, and the second end of the second resonator 130 is connected to the second fixed potential end.
In particular, the band stop filter unit comprises one first resonator 120, one second resonator 130 and one inductive element 110. The first end of the first resonator 120 is connected between the input port a and the first end of the inductive element 110, i.e. the first end of the first resonator 120 is connected to the input port a, i.e. the input port a serves as the input port of the band-stop filtering unit; the first end of the second resonator 130 is connected between the output port B and the second end of the inductive element 110, i.e. the first end of the second resonator 130 is connected to the output port B, i.e. the output port B acts as the output port of the band-stop filtering unit. The second terminal of the first resonator 120 is connected to the first fixed potential terminal, and the second terminal of the second resonator 130 is connected to the second fixed potential terminal. The first fixed potential terminal and the second fixed potential terminal may be equal in potential, and may be, for example, grounded at the same time. Wherein, the band-elimination filter unit comprises an inductive element 110 which can limit the working frequency range of the band-elimination filter unit. The first acoustic wave resonator 120 and the second acoustic wave resonator 130 are respectively connected to two ends of the inductive element 110, so that the inductive element 110 can generate a stop band within a working range, and further, filtering of frequencies within the stop band range is achieved. The first resonator 120 and the second resonator 130 included in the band-stop filtering unit have different resonant frequencies, and the overlapping range of the resonant frequencies of the first resonator 120 and the second resonator 130 can be adjusted according to the requirements of the stop-band bandwidth of the band-stop filter, so that the stop-band bandwidth of the band-stop filtering unit can be improved. It is noted that the overlapping range of the resonance frequencies of the first resonator 120 and the second resonator 130 needs to be set within the operating frequency range of the inductive element 110. To sum up, the first ends of the first resonator 120 and the second resonator 130 are respectively connected to the two ends of the inductive element 110 to form a band-stop filter with pi-type circuit structure, so that the proper stop band is designed in the working range of the inductive element 110 by fully utilizing the resonance frequency characteristics of the resonators, and the band-stop filter with good filter characteristics is formed, thereby improving the characteristics of narrow filter frequency width of a single resonator and poor signal suppression characteristics in the stop band range, realizing the rapid attenuation of input signals in the stop band frequency band, improving the suppression effect of signals in the stop band range, and reducing the loss of transmission signals in the working frequency range of the inductive element 110 and outside the stop band range.
Optionally, a difference between the resonant frequency of the first resonator and the resonant frequency of the second resonator is greater than zero and less than or equal to the stop band bandwidth of the second resonator or the first resonator.
The band-stop filtering unit needs to select a first resonator and a second resonator which have close but unequal resonant frequencies, and the difference between the resonant frequencies of the first resonator and the second resonator needs to be greater than zero and less than or equal to the stop band bandwidth of the second resonator or the first resonator. Therefore, the resonant frequencies of the first resonator and the second resonator can be partially overlapped, and when the resonant frequencies of the first resonator and the second resonator are partially overlapped, the resonant frequencies of the first resonator and the second resonator are combined together, so that the stop band bandwidth of the band-stop filtering unit can be widened.
Optionally, the maximum operating frequency of the inductive element is larger than the stop band frequencies of the first resonator and the second resonator.
Specifically, the inductive element has a characteristic of passing low frequency and high frequency, and the conductive frequency band and the rejection frequency band of the inductive element with different attributes are different, so that the inductive element with appropriate attributes needs to be selected according to the working frequency range of the band-stop filter. I.e. the inductive element may limit the operating frequency range of the band stop filter. With continued reference to fig. 3, it can be seen that the limited operating frequency range of the inductive element is 0-4GHZ, i.e. the inductive element allows frequencies in the range of 0-4GHZ to pass, and the inductive element blocks the frequency band larger than 4GHZ from passing. Therefore, the stop band frequency ranges of the first resonator and the second resonator need to be set in the working range of the inductive element allowing the frequency to pass through, so that a certain frequency segment is screened out in the pass band range of the inductive element, and the function that the band-stop filtering unit passes most of frequencies and only inhibits the frequency of the certain frequency segment from passing through is realized. The maximum working frequency of the inductive element is the maximum passable frequency value of the inductive element, and then the maximum working frequency of the inductive element is set to be larger than the stop band frequency of the first resonator and the second resonator.
Fig. 4 is a schematic structural diagram of another band-stop filter provided in the embodiment of the present invention, and as shown in fig. 4, the band-stop filter includes at least two band-stop filtering units; the difference of the resonant frequencies of the adjacent band-stop filtering units is larger than zero and smaller than or equal to the stopband bandwidth of one of the band-stop filtering units.
Illustratively, the band-stop filter comprises two band-stop filtering units. Wherein the band stop filter comprises two first resonators 120, two second resonators 130 and two inductive elements 110. A first end of the first resonator 121 is connected between the input port a and the first end of the inductive element 111, and a second end of the first resonator 121 is connected to the first fixed potential end. The first ends of the second resonator 131 and the first resonator 122 are connected between the inductive element 111 and the inductive element 112, the second end of the second resonator 131 is connected to the second fixed potential end, and the second end of the first resonator 122 is connected to the first fixed potential end. A first end of the second resonator 132 is connected between the output port B and the inductive element 112, and a second end of the second resonator 132 is connected to a second fixed potential end. Two band-stop filtering units with the resonant frequencies close to but not equal to each other need to be selected, and the difference between the resonant frequencies of the two band-stop filtering units is larger than zero and smaller than or equal to the stopband bandwidth of one of the band-stop filtering units. Therefore, the overlapping range of the resonant frequencies of the two band-stop filtering units can be adjusted according to the requirements of the stop band bandwidth of the band-stop filter, and the two band-stop filtering units are connected in series, so that the resonant frequencies of the two band-stop filtering units are combined together, and the stop band bandwidth of the band-stop filter can be further improved. Illustratively, fig. 5 is a performance diagram of the band-stop filter of fig. 4 according to an embodiment of the present invention. As shown in fig. 5, the abscissa is the frequency of the band-stop filter and the ordinate is the interpolation loss of the signal. Curve 400 is the performance curve of the band stop filter of fig. 4. Comparing fig. 3 and fig. 5, the stopband frequency range of the bandstop filter of fig. 3 is smaller than the stopband frequency range of the bandstop filter of fig. 5. Furthermore, the band-stop filter unit comprises two inductive elements, which can limit the operating frequency range of the band-stop filter unit, and continuing to compare fig. 3 and fig. 5, the operating frequency range of the band-stop filter of fig. 3 is smaller than the operating frequency range of the band-stop filter of fig. 5. It is noted that the overlapping range of the resonance frequencies of the first resonator 121 and the second resonator 131 in fig. 4 needs to be set within the operating frequency range of the inductive element 111; the overlapping range of the resonant frequencies of the first resonator 122 and the second resonator 132 needs to be set within the operating frequency range of the inductive element 112; the operating range of the band-stop filter is the operating frequency of the two inductive elements 110 and together, so that the operating frequency range of the band-stop filter can be further increased.
It should be noted that the stop band bandwidth range of the band-stop filter is set according to the bandwidth of the input signal to be suppressed, and in other embodiments, the band-stop filter can adjust the notch bandwidth by adjusting the number of the band-stop filtering units.
Optionally, the inductive element comprises an inductive element; the first end of the inductive element is used as the first end of the inductive element, and the second end of the inductive element is used as the second end of the inductive element.
The inductor element is a notch filter formed by a chip inductor element manufactured based on Low Temperature Co-fired Ceramic (LTCC) and surface mount device technology, so that the size of the band-stop filter can be reduced, and the requirement of handheld mobile application equipment is met. The first terminal of the inductive element is used as the first terminal of the inductive element, i.e. is connected to the first terminal of the first resonator and the input port. The second end of the inductive element serves as the second end of the inductive element, i.e. is connected to the first end of the second resonator and to the output port. According to the characteristic that the pass-through resistance of the inductance element is high, the working frequency range of the band elimination filter can be limited.
Optionally, the resonator comprises one or more of a surface acoustic wave resonator, a bulk acoustic wave resonator and a thin film cavity acoustic resonator.
The Surface Acoustic Wave (SAW) mainly uses the piezoelectric property of piezoelectric material, and uses input and output transducers to convert the input signal of electric wave into mechanical energy, and after processing, the mechanical energy is converted into electric signal, so as to attain the goal of filtering unnecessary signal and noise and raising signal receiving quality. And compared with the traditional LC filter, the surface acoustic wave resonator is simpler to mount and smaller in volume. The acoustic waves in a bulk acoustic wave resonator propagate in a vertical manner and by storing acoustic wave energy in a piezoelectric material, very high quality can be achieved, converting to a device with large out-of-band attenuation and great competitiveness. Film Bulk Acoustic Resonators (FBARs) have the characteristics of high Q value and easy realization of miniaturization. The surface acoustic wave resonator, the bulk acoustic wave resonator and the film cavity acoustic resonator have the characteristics of small volume, low cost and high Q factor, and can meet the filtering requirements of high specificity and high performance. Surface acoustic wave resonators are suitable for lower frequencies (up to 2.7GHz), bulk acoustic wave resonators and thin film cavity acoustic resonators are suitable for higher frequencies (2.7GHz-6 GHz).
Fig. 6 is a schematic structural diagram of a multi-band-stop filter according to an embodiment of the present invention, as shown in fig. 6, including implementing any band-stop filter 100 in the above embodiment, at least two band-stop filters 100 are connected in series; the difference between the resonant frequencies of at least two band-stop filters 100 is larger than the stop band bandwidth of one of the band-stop filtering units.
At least two bandstop filters 100 with larger difference of resonance frequencies need to be selected, and the difference of the resonance frequencies of at least two bandstop filters 100 is larger than the stopband bandwidth of one bandstop filtering unit. Therefore, each stop band frequency band can be ensured to be not overlapped with each other. At least two band-stop filters 100 are connected in series, and signals of at least two different frequency bands can be filtered according to the filtering requirements of the multi-frequency band-stop filters 100. It should be noted that each band-stop filter 100 correspondingly filters a signal with a certain frequency.
The multi-band-stop filter comprises the band-stop filter provided by any embodiment of the invention, so that the beneficial effects of the band-stop filter provided by the embodiment of the invention are achieved, and the details are not repeated here.
Optionally, the number of band-stop filtering units in different band-stop filters is the same or different.
Exemplarily, fig. 7 is a schematic structural diagram of another multi-band-stop filter provided in the embodiment of the present invention; wherein the multi-band rejection filter is formed by connecting two bandstop filters 100 including a single bandstop filtering unit in series, it should be noted that the multi-band rejection filter includes four resonators with different resonant frequencies, and two inductive elements 110 with different maximum operating frequencies. FIG. 8 is a schematic performance diagram of the multi-band rejection filter of FIG. 7 according to an embodiment of the present invention; wherein, the abscissa is the frequency of the multiband rejection filter, the ordinate is the interpolation loss of the signal, the curve 500 is the performance curve of the multiband rejection filter shown in fig. 7, which can be obtained from the figure, and the multiband rejection filter has two stopband frequencies.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (9)
1. A band elimination filter is characterized by comprising at least one band elimination filter unit; the band elimination filter unit comprises an input port, an output port, at least two resonators and at least one inductive element; wherein the at least two resonators include at least one first resonator and at least one second resonator;
the first end of the first resonator is connected between the input port and the inductive element, the second end of the first resonator is connected with a first fixed potential end, the first end of the second resonator is connected between the output port and the inductive element, and the second end of the second resonator is connected with a second fixed potential end.
2. The band-reject filter according to claim 1, characterized in that the band-reject filtering unit comprises one of the first resonators, one of the second resonators and one of the inductive elements;
the first end of the first resonator is connected between the input port and the first end of the inductive element, the second end of the first resonator is connected with the first fixed potential end, the first end of the second resonator is connected between the output port and the second end of the inductive element, and the second end of the second resonator is connected with the second fixed potential end.
3. The band-stop filter of claim 2, wherein the difference between the resonant frequency of the first resonator and the resonant frequency of the second resonator is greater than zero and less than or equal to the stop band bandwidth of the second resonator or first resonator.
4. The band-reject filter of claim 2, wherein the maximum operating frequency of the inductive element is greater than the reject band frequencies of the first and second resonators.
5. The band-stop filter according to claim 2, characterized in that the band-stop filter comprises at least two of the band-stop filtering units; the difference between the resonant frequencies of the adjacent band-elimination filter units is larger than zero and smaller than or equal to the stopband bandwidth of one of the band-elimination filter units.
6. The band-stop filter according to any of claims 1-5, characterized in that the inductive element comprises an inductive element;
the first end of the inductive element is used as the first end of the inductive element, and the second end of the inductive element is used as the second end of the inductive element.
7. The band reject filter of claim 4, wherein the resonators comprise one or more of surface acoustic wave resonators, bulk acoustic wave resonators, and film bulk acoustic resonators.
8. A multi-band-reject filter comprising at least two band-reject filters according to any one of claims 1 to 7, at least two of the band-reject filters being connected in series; the difference of the resonant frequencies of at least two band-stop filters is larger than the stopband bandwidth of one of the band-stop filtering units.
9. The multiband band reject filter of claim 8, wherein the number of band reject filter elements in different band reject filters is the same or different.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110452411.4A CN113067561A (en) | 2021-04-26 | 2021-04-26 | Band-stop filter and multi-frequency band-stop filter |
| US17/610,515 US20220345109A1 (en) | 2021-04-26 | 2021-08-20 | Band-stop filter and multi-frequency band-stop filter |
| PCT/CN2021/113745 WO2022227347A1 (en) | 2021-04-26 | 2021-08-20 | Band-stop filter and multi-frequency band-stop filter |
| JP2022513185A JP2023527098A (en) | 2021-04-26 | 2021-08-20 | Bandstop filters and multibandstop filters |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110452411.4A CN113067561A (en) | 2021-04-26 | 2021-04-26 | Band-stop filter and multi-frequency band-stop filter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2022227347A1 (en) * | 2021-04-26 | 2022-11-03 | 安徽安努奇科技有限公司 | Band-stop filter and multi-frequency band-stop filter |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2022227347A1 (en) * | 2021-04-26 | 2022-11-03 | 安徽安努奇科技有限公司 | Band-stop filter and multi-frequency band-stop filter |
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