CN115425377B - A double-passband balanced filter based on ring resonator loading - Google Patents

Abstract

A double-passband balanced filter based on square ring loading, including a dielectric substrate. One side of the dielectric substrate is provided with a microstrip line. The microstrip line includes a first input port, a second input port, a first output port, and a second The output port and four mutually gap-coupled ring resonators, the first input port, the second input port, the first output port and the second output port are arranged in a rectangular array, and the two ends of the ring resonator form an H-shaped Ring arms, the ends of the two ring arms far away from each other are respectively equipped with central loading branches. The ring resonator based on square ring loading proposed by the present invention has multi-mode characteristics and can be used to design and realize two passbands. The resonator design is simple and compact, has a symmetrical structure, and is easy to connect to high levels. Through the connection between the ring arms, The gap, additional H-type coupling lines and coupling blocks enable flexible regulation of the two passband bandwidths, and finally the coupling feeder meets the external quality factor requirements of the two passbands.

Description

A double-passband balanced filter based on ring resonator loading

Technical field

The invention relates to the field of double-passband filters, and in particular to a double-passband balanced filter based on ring resonator loading.

Background technique

With the rapid development of wireless communication technology, spectrum resources are becoming increasingly scarce, and the electromagnetic environment has become increasingly complex. Application scenarios such as mobile communications, radar detection, and electronic countermeasures are facing development needs such as multi-band, miniaturization, and anti-interference. In communication systems, balanced circuits have stronger resistance to environmental noise than single-ended circuits. In order to solve the above challenges faced in communication systems, in recent years, miniaturized multi-passband balanced filters with excellent differential performance and immunity to noise interference have been developed It has attracted the research attention of many scholars.

Compared with traditional single-port unbalanced filters, in the design of balanced filters, not only must a good differential mode response be achieved, but also sufficient common mode suppression characteristics must be achieved, especially for multi-passband balanced filters. It is also very important to achieve flexible control of the center frequency and bandwidth of each passband.

Contents of the invention

The purpose of the invention is to provide a double-passband balanced filter based on ring resonator loading, which has the characteristics of miniaturization, compact structure, good differential mode transmission and common mode suppression characteristics, and the center frequency and bandwidth of the two passbands Can be flexibly adjusted.

The technical solution adopted by the present invention to solve the above technical problems is: a double-passband balanced filter based on ring resonator loading, including a dielectric substrate, a microstrip line is provided on one side of the dielectric substrate, and the microstrip line includes a first An input port, a second input port, a first output port, a second output port and four mutually gap-coupled ring resonators. The first input port, the second input port, the first output port and the second output port form a rectangular array. Arranged such that the first input port and the second input port are located on the same side of the rectangular array, the first output port and the second output port are located on the other side of the rectangular array, between the first input port and the second input port, and The first output port and the second output port are respectively arranged symmetrically with respect to the center line extending along the X direction of the rectangular array, the first input port and the first output port, and the second input port and the second output port. They are arranged symmetrically about the center line extending along the Y direction of the rectangular array;

Four ring resonators are arranged at intervals along the X direction. The middle part of the ring resonator extends along the Y direction. Both ends of the ring resonator along the Y direction form an H-shaped ring arm. The ring arm includes a cross arm extending along the X direction. , and two longitudinal arms respectively connected to both ends of the transverse arm. Both longitudinal arms extend along the Y direction and are arranged symmetrically about the Y-direction centerline of the transverse arm. The two annular arms of the same ring resonator are about the rectangular array. The center line extending along the X direction is symmetrically arranged. The ends of the two annular arms far away from each other are respectively provided with a central loading branch. The central loading branch is located between the two ends of the H shape of the annular arm. The shape of the central loading branch extends along the Y direction. rectangle;

A first input feeder and a second input feeder are connected to the first input port, a third input feeder and a fourth input feeder are connected to the second input port, and a first output feeder and a second output feeder are connected to the first output port. , the third output feeder and the fourth output feeder are connected to the second output port, and the first input feeder, the third input feeder, the first output feeder and the third output feeder respectively pass through the gap with the H-shaped end of the ring arm close to itself Coupling realizes feeding, and the second input feeder, the fourth input feeder, the second output feeder and the fourth output feeder respectively realize feeding through gap coupling with the middle part of the ring resonator close to itself.

Preferably, an H-shaped coupling line is provided between two adjacent central loading branches of the second and third ring resonators spaced apart along the X direction, and the two ends of the H-shaped coupling line are connected to the two central loading branches respectively. Feeding is achieved via gap coupling.

Preferably, a coupling block is provided between adjacent ring arms of the first and second ring resonators and the third and fourth ring resonators spaced apart along the X direction. The shape of the coupling block is rectangular. The coupling block Feeding is realized through gap coupling with two annular arms respectively.

According to the above technical solution, the beneficial effects of the present invention are:

1. The ring resonator based on square ring loading proposed by the present invention has multi-mode characteristics and can be used to design and realize two passbands. The resonator design is simple and compact, has a symmetrical structure, and is easy to connect to high levels.

2. The two passband center frequencies of the double-passband balanced filter based on ring resonator loading proposed by the present invention can be flexibly adjusted through the size of the ring arms and the size of the central loading branches, and through the gaps between the ring arms, The additional H-type coupling lines and coupling blocks enable flexible regulation of the two passband bandwidths, and finally the coupling feeder meets the external quality factor requirements of the two passbands.

3. The double-passband balanced filter based on ring resonator loading proposed by the present invention has the characteristics of miniaturization, compact structure, flexible design, high out-of-band suppression of differential mode response and high isolation between passbands, and good common-mode response suppression characteristics. Etc.

Description of the drawings

Figure 1 is a schematic diagram of the present invention;

Figure 2 is a schematic diagram of a microstrip line;

Figure 3 is a schematic diagram of a ring resonator;

Figure 4 is a simulation curve diagram of the present invention.

Labels in the figure: 1. Dielectric substrate, 2. Microstrip line, 3. First input port, 4. Second input port, 5. First output port, 6. Second output port, 7. First input feeder line, 8. The second input feeder, 9. The fourth input feeder, 10. The third input feeder, 11. The first output feeder, 12. The second output feeder, 13. The fourth output feeder, 14. The third output feeder, 15 , Ring arm, 16. Center loading branch, 17. H-shaped coupling line, 18. Coupling block.

Detailed ways

Referring to the accompanying drawings, the specific implementation is as follows:

As shown in Figure 1, a double-passband balanced filter based on ring resonator loading includes a dielectric substrate 1, and a microstrip line 2 is provided on one side of the dielectric substrate 1.

As shown in Figure 2, the microstrip line 2 includes a first input port 3, a second input port 4, a first output port 5, a second output port 6 and four mutually gap-coupled ring resonators. The first input port 3, the second input port 4, the first output port 5 and the second output port 6 are arranged in a rectangular array, and the first input port 3 and the second input port 4 are located on the same side of the rectangular array. Output port 5 and second output port 6 are located on the other side of the rectangular array.

As shown in Figure 2, the first input port 3 and the second input port 4, and the first output port 5 and the second output port 6 are respectively arranged symmetrically with respect to the center line extending along the X direction of the rectangular array. The first input port 3 and the first output port 5, and the second input port 4 and the second output port 6 are respectively arranged symmetrically with respect to the center line extending along the Y direction of the rectangular array, which can achieve a good differential mode response. and common mode rejection characteristics.

As shown in Figure 2-3, four ring resonators are arranged at intervals along the X direction. The middle part of the ring resonator extends along the Y direction. Both ends of the ring resonator along the Y direction form an H-shaped ring arm 15 respectively. The arm 15 includes a transverse arm extending in the The two annular arms 15 of the device are arranged symmetrically about the center line of the rectangular array extending along the X direction.

As shown in Figure 2-3, one end of the two annular arms 15 away from each other is respectively provided with a central loading branch 16. The central loading branch 16 is located between the two ends of the H shape of the annular arm 15. The shape of the central loading branch 16 is along the A rectangle extending in the Y direction.

As shown in Figure 2-3, by synchronously adjusting the H-shaped length L ₂ of multiple ring arms 15, the center frequencies of the two passbands can be controlled simultaneously. By adjusting the length L ₁ of the central loading branch 16 along the Y direction and along the The width W ₁ in the X direction can independently control the center frequency of the second passband. That is to say, when designing a double-passband filter, you can first determine the center frequency of the first passband by adjusting the total length L2 of the H-shape of the annular arm 15, and then determine the center frequency of the first passband by _adjusting L1 _and W1 _. The center frequencies of the two passbands enable flexible control of the center frequencies of the two passbands.

The double-passband balanced filter is a fourth-order Chebyshev-type filter. The ring resonators loaded by four square rings are directly coupled through gaps. The bandwidth of the two passbands can be adjusted by adjusting the gap width. In addition, as shown in Figure 2, an H-shaped coupling line 17 is provided between two adjacent center loading branches 16 of the second and third ring resonators spaced apart along the X direction. The two ends are respectively connected to the two central loading branches 16 to realize feeding through gap coupling. By adjusting the length L ₃ of the H-shaped coupling line 17 along the Y direction, the bandwidth of the second passband can be independently controlled.

As shown in Figure 2, a coupling block 18 is provided between the adjacent ring arms 15 of the first and second ring resonators and the third and fourth ring resonators spaced apart along the X direction. The coupling block 18 is rectangular in shape, and the coupling block 18 is respectively coupled with the two annular arms 15 to realize power feeding through gap coupling. By adjusting the length and width of the coupling block 18, the bandwidth of the two passbands can be fine-tuned.

As shown in Figure 2, a first input feeder 7 and a second input feeder 8 are connected to the first input port 3, a third input feeder 10 and a fourth input feeder 9 are connected to the second input port 4, and the first output port The first output feeder 11 and the second output feeder 12 are connected to the port 5, and the third output feeder 14 and the fourth output feeder 13 are connected to the second output port 6. The first input feeder 7, the third input feeder 10, the first output feeder 11 and the third output feeder 14 are respectively connected to the H-shaped end of the annular arm 15 close to itself to achieve power feeding through gap coupling. The second input feeder 8, the fourth The input feeder 9, the second output feeder 12 and the fourth output feeder 13 are respectively coupled with the middle part of the ring resonator close to itself through gap coupling to realize feeding. By adjusting the length of the input feeder and output feeder, flexible control of the external quality factor of the two passbands can be achieved.

Figure 4 illustrates the differential mode frequency simulation response of the double-passband balanced filter based on the ring resonator loading of the present invention. The simulation results show that the center frequencies of the two passbands are 5.4GHz and 6.3GHz respectively, and the two passbands are 3- The dB relative bandwidths are 2.6% and 1.9% respectively, resulting in a total of two transmission zero points TZ1 and TZ2, located at 4.98GHz and 5.76GHz respectively.

Claims (3)

1. A dual passband balanced filter based on loading of a ring resonator, characterized by: the micro-strip line structure comprises a medium substrate (1), wherein one side of the medium substrate (1) is provided with a micro-strip line (2), the micro-strip line (2) comprises a first input port (3), a second input port (4), a first output port (5), a second output port (6) and four ring resonators which are mutually coupled in a gap mode, the first input port (3), the second input port (4), the first output port (5) and the second output port (6) are arranged in a rectangular array, the first input port (3) and the second input port (4) are positioned on the same side of the rectangular array, the first output port (5) and the second output port (6) are positioned on the other side of the rectangular array, and the first input port (3) and the second input port (4) and the first output port (5) and the second output port (6) are symmetrically arranged along the central line extending along the X direction of the rectangular array respectively;

the four ring resonators are sequentially arranged at intervals along the X direction, the middle part of each ring resonator extends along the Y direction, two ends of each ring resonator along the Y direction respectively form an H-shaped ring arm (15), each ring arm (15) comprises a cross arm extending along the X direction and two longitudinal arms respectively connected with two ends of the cross arm, each longitudinal arm extends along the Y direction and is symmetrically arranged about the Y-direction central line of the cross arm, the two ring arms (15) of the same ring resonator are symmetrically arranged about the central line of the rectangular array extending along the X direction, one ends, far away from each other, of each ring arm (15) are respectively provided with a central loading branch (16), each central loading branch (16) is positioned between the two ends of the H shape of each ring arm (15), and each central loading branch (16) is rectangular extending along the Y direction;

the first input port (3) is connected with a first input feeder (7) and a second input feeder (8), the second input port (4) is connected with a third input feeder (10) and a fourth input feeder (9), the first output port (5) is connected with a first output feeder (11) and a second output feeder (12), the second output port (6) is connected with a third output feeder (14) and a fourth output feeder (13), the first input feeder (7), the third input feeder (10), the first output feeder (11) and the third output feeder (14) are respectively and mutually connected with one end of an H shape close to a self annular arm (15) to realize feeding through gap coupling, and the second input feeder (8), the fourth input feeder (9), the second output feeder (12) and the fourth output feeder (13) are respectively and mutually connected with the middle part close to the self annular resonator to realize feeding through gap coupling.

2. A dual passband balanced filter based on loading of ring resonators as defined in claim 1 wherein: an H-shaped coupling line (17) is arranged between two adjacent center loading branches (16) of the second ring resonator and the third ring resonator which are arranged at intervals along the X direction, and two ends of the H-shaped coupling line (17) are respectively connected with the two center loading branches (16) in a gap coupling mode to realize feeding.

3. A dual passband balanced filter based on loading of ring resonators as defined in claim 2 wherein: coupling blocks (18) are arranged between adjacent annular arms (15) of the first annular resonator, the second annular resonator and the third annular resonator which are arranged at intervals along the X direction, the coupling blocks (18) are rectangular, and the coupling blocks (18) are respectively coupled with the two annular arms (15) through gaps to realize feeding.