WO2019213916A1 - Cavity filter and communication radio frequency device - Google Patents

Abstract

A cavity filter (40) and a communication radio frequency device, the cavity filter (40) comprising a signal input end (401), a signal output end (402), and at least four resonators (403-406) that are sequentially arranged at interconnected intervals from end to end, wherein the signal input end (401) is coupled with the first resonator (403) of the resonators, the signal output end (402) is coupled with the last resonator (406) of the resonators, and a coupling window (407) is disposed at the interval between the first resonator (403) and the last resonator (406); thus, two transmission zero points are added in a passband of the cavity filter (40), and fluctuations in insertion loss may thus be notably reduced.

Description

Cavity filter and communication RF device

[Technical Field]

The present application relates to the field of filters, and in particular, to a cavity filter and a communication RF device.

 【Background technique】

The cavity filter has interpolation loss fluctuation in the passband range, and the insertion loss fluctuation refers to the difference between the maximum value and the minimum value of the insertion loss of the filter in the passband frequency range.

In the band-pass filter, the passband range is characterized by small insertion loss near the center frequency and large insertion loss of the side frequency. The passband range refers to the frequency range of the electromagnetic wave that the bandpass filter allows. Generally, the insertion loss of the passband sideband is greatly affected by the out-of-band transmission zero point, and the stronger the out-of-band rejection, the larger the insertion loss of the sideband, resulting in a larger fluctuation of the passband insertion loss. With the development of communication technology, the requirements for out-of-band suppression are more stringent. Cavity filters generally need to add out-of-band transmission zeros to ensure that the out-of-band rejection meets the requirements, which will cause the insertion loss fluctuations in the passband to become larger. However, the prior art does not effectively deal with the problem of large fluctuations in insertion loss.

Therefore, it is necessary to propose a cavity filter and a communication RF device to solve the above technical problems.

 [Summary of the Invention]

The technical problem to be solved by the present application is to provide a cavity filter and a communication RF device, which can effectively control the fluctuation of the insertion band loss and significantly reduce the insertion loss fluctuation.

In order to solve the above technical problem, the first technical solution of the present application is to provide a cavity filter, the cavity filter includes a signal input end, a signal output end, and at least four resonators arranged in an end-to-end interval; The input end is coupled to the first resonator in the resonator, and the signal output end is coupled to the last resonator in the resonator; wherein the first resonator and the last resonator are provided with a coupling window at the interval, through coupling The window adds two transmission zeros in the passband of the cavity filter.

In order to solve the above technical problem, the second technical solution of the present application is to provide a communication radio frequency device, the communication radio frequency device includes a cavity filter, and the cavity filter is used in a signal transmitting and receiving circuit portion of the communication radio frequency device to perform signal processing. Selecting; wherein the cavity filter comprises a signal input end, a signal output end, at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, the signal output end and the resonator The last resonator is coupled; a spacing window is provided at the interval between the first resonator and the last resonator, and two transmission zeros are added in the passband of the cavity filter through the coupling window.

The beneficial effects of the present application are: different from the prior art, the cavity filter of the present application includes a signal input end, a signal output end, at least four resonators arranged in an end-to-end interval; the signal input end and the first of the resonators The resonators are coupled, and the signal output is coupled to the last resonator in the resonator; by adding a coupling window at the interval between the first resonator and the last resonator, thereby increasing the pass band of the cavity filter The two transmission zero points can effectively control the passband insertion loss fluctuation of the cavity filter, so that the insertion loss fluctuation is significantly reduced.

 [Description of the Drawings]

1 is a schematic structural view of an embodiment of a cavity filter in the prior art;

2 is a schematic diagram of an equivalent circuit of an embodiment of the cavity filter of FIG. 1;

3 is a schematic diagram of insertion loss fluctuations of an embodiment of the cavity filter of FIG. 1;

4 is a schematic structural diagram of an embodiment of a cavity filter provided by the present application;

Figure 5 is an equivalent circuit diagram of an embodiment of the cavity filter of Figure 4;

FIG. 6 is a schematic diagram of the insertion loss fluctuation of an embodiment of the cavity filter of FIG. 4. FIG.

【detailed description】

The present application provides a cavity filter and a communication radio frequency device. To make the purpose, technical solution and technical effect of the present application clearer and clearer, the following further describes the present application in detail, and it should be understood that the specific implementation regulations described herein are only used for This application is not intended to limit the application.

In order to effectively control the passband insertion loss fluctuation of the cavity filter, the insertion loss fluctuation is significantly reduced. The cavity filter provided by the present application includes a signal input end, a signal output end, and at least four resonators which are arranged at intervals in order. The signal input end is coupled to the first resonator in the resonator, and the signal output end is coupled to the last resonator in the resonator, by setting a coupling window at the interval between the first resonator and the last resonator, thereby Two transmission zeros are added to the passband of the cavity filter, which can significantly reduce the insertion loss fluctuation.

Please refer to FIG. 1 to FIG. 3 . FIG. 1 is a schematic structural diagram of an embodiment of a cavity filter in the prior art. As shown in FIG. 1, the cavity filter 10 includes a signal input terminal 101, a signal output terminal 102, and four first resonators 103, a second resonator 104, a third resonator 105, and a fourth resonance which are sequentially disposed at intervals. The first resonator 103 and the second resonator 104 are connected through a coupling window, the second resonator 104 is connected to the third resonator 105 through a coupling window, and the third resonator 105 and the fourth resonator 106 are coupled through a coupling window. connection. In order to complete the transmission of the signal, the cavity filter 10 further includes a first tap 113 and a second tap 114, wherein the signal input terminal 101 is coupled to the first resonator 103 through the first tap 113, and the signal output terminal 102 passes through The two taps 114 are coupled to the fourth resonator 106.

Please refer to FIG. 2. FIG. 2 is an equivalent circuit diagram of an embodiment of the cavity filter of FIG. As shown in FIG. 2, the first resonator 201 and the second resonator 202 are connected by a coupling window 206, and the second resonator 202 is connected to the third resonator 203 through a coupling window 207, and the third resonator 203 and the fourth resonator 204 is connected through a coupling window 208, and the signal input terminal 210 is connected to the first resonator 201 through a first tap 209, and the signal output terminal 212 is connected to the fourth resonator 204 through a second tap 211. After the signal to be processed enters the band pass filter through the signal input terminal 210, it is transmitted to the first resonator 201 via the first tap 209, and the first resonator 201 transmits the signal to the second resonator 202 through the coupling window 206, the second The resonator 202 transmits a signal to the third resonator 203 through the coupling window 207, the third resonator 203 transmits a signal to the fourth resonator 204 through the coupling window 208, and the fourth resonator 204 transmits the signal to the second tap 211 via the second tap 211 Signal output 212.

Please refer to FIG. 3. FIG. 3 is a schematic diagram of the insertion loss fluctuation of the embodiment of the cavity filter of FIG. As shown in Fig. 3, the abscissa represents frequency and its unit is gigahertz; the ordinate represents insertion loss, and its unit is decibel. The point m3 in the figure represents an insertion loss of -1.4438 decibels at a frequency of 1.99 GHz; the point m4 in the figure represents an insertion loss of -1.5145 decibels at a frequency of 2.01 GHz; the point m5 in the figure represents a frequency of 2.002 GW The insertion loss at Hertz is -0.887 dB. Among them, the point corresponding to -5.987 decibels is the maximum value of insertion loss, and the -1.5145 decibel corresponding to point m4 is the minimum value of insertion loss, then the fluctuation of the insertion band loss is: A=-0.987-(-1.5145)=0.5275 decibels. The two passband side frequencies of the cavity filter are 1.99 GHz and 2.01 GHz, respectively, and the center frequency is 2 GHz.

As can be seen from the above, the suppression of the passband sideband in the prior art is poor, and the passband insertion loss fluctuates greatly. In order to reduce the fluctuation of the passband insertion loss, the present application adds two transmission zero points symmetrically with respect to the center frequency in the passband, which will be described in detail below with reference to FIGS. 4-6.

Please refer to FIG. 4. FIG. 4 is a schematic structural diagram of an embodiment of a cavity filter provided by the present application. The cavity filter includes four resonators arranged end to end in sequence, as illustrated in FIG. 4 .

The cavity filter 40 of the present application includes a signal input end 401, a signal output end 402, and four first resonators 403, a second resonator 404, a third resonator 405, and a fourth resonator 406 which are disposed at intervals in order. The first resonator and the last resonator are the first resonator 403 and the fourth resonator 406, respectively, and a coupling window 407 is disposed between the first resonator 403 and the fourth resonator 406. In the above manner, by providing the coupling window 407 between the first resonator 403 and the fourth resonator 406, two transmission zeros are added in the pass band of the cavity filter 40, thereby significantly reducing the pass band. The insertion loss fluctuates.

Specifically, in order to control the passband insertion loss fluctuation of the cavity filter by adding two transmission zero points in the passband, the insertion loss fluctuation is significantly reduced, and the application is provided in the cavity filter 40 by setting the coupling window 407. Add two transmission zeros symmetrically with respect to the center frequency of the resonator.

Further, in another embodiment, in order to complete the transmission of the signal, the cavity filter 40 further includes a first tap 413 and a second tap 414, wherein the signal input terminal 401 passes through the first tap 413 and four resonances. The first resonator in the device is coupled, and the signal output 402 is coupled to the last of the four resonators via a second tap 414.

The cavity filter 40 is a band pass filter, which is a filter that allows electromagnetic waves of a specific frequency range to pass while shielding electromagnetic waves of other frequency ranges. As shown in FIG. 4, the electromagnetic waves transmitted to the signal input terminal 401 generally include electromagnetic waves of a specific frequency range and other frequency ranges, and then the electromagnetic waves outputted through the signal output terminal 402 are specific after the signals are coupled and transmitted in the band pass filter. Electromagnetic waves in the frequency range, while electromagnetic waves in other frequency ranges are filtered out, that is, the effect of filtering out clutter is achieved. Specifically, a coupling window 407 is disposed between the first resonator 403 and the fourth resonator 406, and the size of the coupling window 407 matches the signal frequency corresponding to the cavity filter 40, and the size of the coupling window affects the band pass filtering. The specific frequency range of the electromagnetic wave that the device is allowed to pass. In a specific application scenario, the size of the coupling window should be adjusted according to the actual required passband range.

Further, in another embodiment, the cavity filter 40 further includes a cover plate (not shown in FIG. 1) and at least one coupling screw. In this embodiment, four coupling screws are specifically disposed as an example. The four coupling screws are respectively used to adjust the coupling strength between the two connected resonators. Wherein, the first coupling screw 408 is disposed at the coupling window 407 between the first resonator 403 and the fourth resonator 406 for adjusting the coupling strength between the first resonator 403 and the fourth resonator 406, the first resonance A second coupling screw 409 is provided at the coupling window between the 403 and the second resonator 404 for adjusting the coupling strength between the first resonator 403 and the second resonator 404, the second resonator 404 and the third resonator A third coupling screw 410 is disposed at the coupling window between 405 for adjusting the coupling strength between the second resonator 404 and the third resonator 405, and a coupling window between the third resonator 405 and the fourth resonator 406 A fourth coupling screw 411 is provided for adjusting the coupling strength between the third resonator 405 and the fourth resonator 406, and one end of the four coupling screws 408, 409, 410, 411 is respectively threaded and corresponding to the cover plate The screw holes are connected, and the other ends are respectively extended into the corresponding four coupling windows, and the coupling strength between the two connected resonators is adjusted by adjusting the depth of the coupling screw extending into the coupling window. Specifically, the depth of the coupling screw extending into the coupling window is positively correlated with the coupling strength between the two connected resonators, that is, the deeper the depth of the coupling coupling screw extends into the coupling window, the more the coupling strength between the connected two resonators Strong, the shallower the depth of the adjustment coupling screw extending into the coupling window, the weaker the coupling strength between the two connected resonators. In addition, since the coupling strength has a certain influence on the insertion loss fluctuation, the insertion loss fluctuation can be obtained by adjusting the coupling strength.

Further, the four resonators 403, 404, 405, and 406 in this embodiment are all metal resonators, and the four coupling screws 408, 409, 410, and 411 are all metal coupling screws, and four metal resonators 403 404, 405, 406 are respectively provided with a metal frequency modulation screw 412. One end of the metal frequency modulation screw 412 is screwed to the screw hole on the cover plate, and the other end extends into the metal resonator, and the metal frequency adjustment screw 412 is extended to the metal by adjusting the metal frequency modulation screw 412. The depth within the resonator thus adjusts the frequency of the metal resonator.

The resonator in this embodiment is a metal resonator. In other embodiments, the resonator may also be other types of resonators, such as dielectric resonators.

The four resonators 403, 404, 405, and 406 are provided in this embodiment. In other embodiments, five, six or more resonators may be disposed. The specific number of resonators is here. Not limited.

At the same time, in order to facilitate the fixing of the cover plate and to achieve a better sealing effect, in the present embodiment, the cavity filter 40 further includes a cavity wall, and the cavity wall is correspondingly provided with a screw hole (not shown). To fix the cover.

Different from the prior art, the cavity filter of the present application includes a signal input end, a signal output end, and at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, and the signal is coupled. The output is coupled to the last resonator in the resonator; by providing a coupling window at the interval between the first resonator and the last resonator, two transmission zeros are added in the passband of the cavity filter, thereby enabling The passband insertion loss fluctuation of the cavity filter is effectively controlled, so that the insertion loss fluctuation is significantly reduced.

In order to clearly explain the working principle of the cavity filter of any of the above embodiments, the cavity filter includes four metal resonators which are sequentially spaced apart from each other, and a coupling window is disposed between the two adjacent metal resonators. Explain as an example. Please refer to FIG. 5. FIG. 5 is an equivalent circuit diagram of an embodiment of the cavity filter of FIG.

Specifically, the cavity filter is taken as an example of a band pass filter, wherein the four metal resonators 501, 502, 503, and 504 are respectively connected through four coupling windows 505 and 506 respectively disposed between the two resonators. 507, 508 are connected to form a band pass filter, the first metal resonator 501 is connected to the signal input terminal 510 through the first tap 509, and the fourth metal resonator 504 is connected to the signal output terminal 512 through the second tap 511.

In this embodiment, the four metal resonators 501, 502, 503, and 504, and the signal input terminal 510 and the signal output terminal 512 are both grounded to prevent leakage.

After the signal to be processed enters the band pass filter through the signal input terminal 510, it is transmitted to the first metal resonator 501 via the first tap 509, and the first metal resonator 501 transmits the signal to the fourth metal resonance through the first coupling window 505. The fourth metal resonator 504 transmits a signal to the signal output terminal 512 via the second tap 511, while the first metal resonator 501 transmits the signal to the second metal resonator 502 through the second coupling window 506. The second metal resonator 502 transmits a signal to the third metal resonator 503 through the third coupling window 507, and the third metal resonator 503 transmits the signal to the fourth metal resonator 504 through the fourth coupling window 508, the fourth metal resonance The 504 transmits a signal to the signal output 512 via the second tap 511. The electromagnetic waves transmitted to the signal input terminal 510 generally include electromagnetic waves of a specific frequency range and other frequency ranges. After the signals are coupled and transmitted in the band pass filter, the signals output through the signal output terminal 512 only contain electromagnetic waves of a specific frequency range, and Other ranges of electromagnetic waves are filtered out, which also achieves the effect of filtering out clutter. In the above manner, by adding a first coupling window 505 between the first metal resonator 501 and the fourth metal resonator 504, two symmetry with respect to the center frequency of the resonator is added in the pass band of the filter. The zero point, in turn, can reduce the insertion loss fluctuation.

In this embodiment, a resonant circuit is formed by four metal resonators 501, 502, 503, 504 and four coupling windows 505, 506, 507, 508, and signals of different frequencies in the signal to be processed are selected to filter out clutter Then, the processed signal is output to the signal output terminal 512 via the second tap 511.

Please refer to FIG. 6. FIG. 6 is a schematic diagram of the insertion loss fluctuation of the embodiment of the cavity filter of FIG. As shown in Fig. 6, the abscissa represents frequency and its unit is gigahertz; the ordinate represents insertion loss, and its unit is decibel. The point m1 in the figure represents an insertion loss of -1.4862 decibels at a frequency of 1.99 GHz; the point m3 in the figure represents an insertion loss of -1.4997 decibels at a frequency of 2.01 GHz; the point m2 in the figure represents a frequency of 1.992 GW. The insertion loss at Hertz is -1.284 dB. Among them, the point -1.284 decibel corresponding to point m2 is the maximum value of insertion loss, and the -1.4997 decibel corresponding to point m3 is the minimum value of insertion loss. The fluctuation of the insertion band loss is: A=-1.284-(-1.4997)=0.2157 decibels. The two passband side frequencies of the cavity filter are 1.99 GHz and 2.01 GHz, respectively, and the center frequency is 2 GHz.

It can be seen from the above that the cavity filter with the coupling window 407 added in the present application can reduce the insertion loss fluctuation in the passband range. In the prior art, the insertion loss fluctuation when the coupling window 407 is not increased is 0.5275. Decibel, and the coupling window 407 is added to the present application and dropped to 0.2157 decibels, indicating that the present application can significantly reduce the insertion loss fluctuation.

Different from the prior art, the cavity filter of the present application includes a signal input end, a signal output end, and at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, and the signal is coupled. The output is coupled to the last resonator in the resonator; by providing a coupling window at the interval between the first resonator and the last resonator, two transmission zeros are added in the passband of the cavity filter, thereby enabling The passband insertion loss fluctuation of the cavity filter is effectively controlled, so that the insertion loss fluctuation is significantly reduced.

The application also provides a communication radio frequency device, the communication radio frequency device includes a cavity filter, and the cavity filter is used in a signal transceiving circuit portion of the communication radio frequency device to select a signal; wherein the cavity filter includes a signal input end a signal output end, at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, and the signal output end is coupled to the last resonator in the resonator; the first resonance A coupling window is provided at the interval between the last resonator and the last resonator, and two transmission zeros are added in the passband of the cavity filter through the coupling window.

Wherein, the communication radio frequency device is any one of a simplexer, a duplexer, a splitter, a combiner or a tower top amplifier.

Regarding the structure of the cavity filter, the above has been described in detail and will not be described again.

Different from the prior art, the cavity filter of the present application includes a signal input end, a signal output end, and at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, and the signal is coupled. The output is coupled to the last resonator in the resonator; by providing a coupling window at the interval between the first resonator and the last resonator, two transmission zeros are added in the passband of the cavity filter, thereby enabling The passband insertion loss fluctuation of the cavity filter is effectively controlled, so that the insertion loss fluctuation is significantly reduced.

The above description is only the embodiment of the present application, and thus does not limit the scope of patent protection of the present application. Any equivalent structure or equivalent process transformation made by using the specification and the contents of the drawings, or directly or indirectly applied to other related The technical field is equally included in the scope of patent protection of the present application.

Claims (19)

1. A cavity filter, comprising: a signal input end, a signal output end, at least four resonators arranged in an end-to-end interval; the signal input end and the resonator The first resonator is coupled, and the signal output is coupled to the last resonator in the resonator;

   Wherein the spacing between the first resonator and the last resonator is provided with a coupling window to add two transmission zeros in the passband of the cavity filter through the coupling window.
2. The cavity filter according to claim 1, wherein the cavity filter is a band pass filter, and a coupling window is provided at an interval between the first resonator and the last resonator, The coupling window adds two transmission zeros that are bilaterally symmetric with respect to a center frequency of the resonator within the passband of the cavity filter.
3. The cavity filter of claim 1 wherein the size of the coupling window matches the frequency of the signal corresponding to the cavity filter transmission.
4. The cavity filter according to claim 1, wherein the cavity filter further comprises a cover plate and at least one coupling screw, and one end of the coupling screw is screwed to the screw hole of the cover plate, The other end extends into the coupling window to adjust the coupling strength between the first resonator and the last resonator by adjusting the depth of the coupling screw extending into the coupling window.
5. The cavity filter according to claim 4, wherein a depth in which said coupling screw extends into said coupling window is positively correlated with a coupling strength between said first resonator and said last resonator .
6. The cavity filter according to claim 4, wherein the at least four resonators which are sequentially connected at intervals are metal resonators, and the coupling screw is a metal coupling screw.
7. The cavity filter according to claim 6, wherein the interior of the at least four metal resonators are respectively provided with a metal frequency modulation screw, and one end of the metal frequency modulation screw is threaded with a screw hole of the cover plate. The other end extends into the metal resonator to adjust the frequency of the metal resonator by adjusting the depth of the metal frequency modulation screw extending into the metal resonator.
8. The cavity filter according to claim 1, wherein said input port is connected to said first resonator through a first tap, and said output port is connected to said last resonator through a second tap.
9. The cavity filter according to claim 1, wherein the at least four resonators that are sequentially spaced apart from each other are dielectric resonators.
10. A communication radio frequency device, comprising: a cavity filter, wherein the cavity filter is configured to be disposed in a signal transceiving circuit portion of the communication radio frequency device to select a signal;

    Wherein, the cavity filter comprises a signal input end, a signal output end, at least four resonators arranged in an end-to-end interval; the signal input end is coupled to the first resonator in the resonator, a signal output end coupled to the last resonator in the resonator; a spacing window is provided at an interval between the first resonator and the last resonator, and the cavity filter is passed through the coupling window Add two transmission zeros in the passband.
11. The communication radio frequency device according to claim 10, wherein the cavity filter is a band pass filter, and a coupling window is disposed at an interval between the first resonator and the last resonator. The coupling window adds two transmission zeros that are bilaterally symmetric with respect to the center frequency of the resonator within the passband of the cavity filter.
12. The communication radio frequency device according to claim 10, wherein the size of the coupling window matches a signal frequency corresponding to the cavity filter transmission.
13. The communication radio frequency device according to claim 10, wherein the cavity filter further comprises a cover plate and at least one coupling screw, one end of the coupling screw is threadedly connected to the screw hole of the cover plate, and One end extends into the coupling window, and the coupling strength between the first resonator and the last resonator is adjusted by adjusting a depth in which the coupling screw extends into the coupling window.
14. The communication radio frequency device according to claim 13, wherein a depth in which said coupling screw extends into said coupling window is positively correlated with a coupling strength between said first resonator and said last resonator.
15. The communication radio frequency device according to claim 13, wherein said at least four resonators arranged in an end-to-end interval are metal resonators, and said coupling screw is a metal coupling screw.
16. The communication radio frequency device according to claim 15, wherein the inside of the at least four metal resonators are respectively provided with a metal frequency modulation screw, and one end of the metal frequency modulation screw is screwed to the screw hole of the cover plate. The other end extends into the metal resonator to adjust the frequency of the metal resonator by adjusting the depth of the metal frequency modulation screw extending into the metal resonator.
17. The communication radio frequency device according to claim 10, wherein said input port is connected to said first resonator through a first tap, and said output port is connected to said last resonator through a second tap.
18. The communication radio frequency device according to claim 10, wherein said at least four resonators arranged in series with each other at intervals are dielectric resonators.
19. The communication radio frequency device according to claim 10, wherein said communication radio frequency device is any one of a simplexer, a duplexer, a splitter, a combiner, or a tower top amplifier.