CN218827755U - A high-selectivity planar dual-cavity dual-mode chip filter - Google Patents

Abstract

The utility model relates to a high-selectivity planar dual-cavity dual-mode patch filter, which comprises a filter body, the filter body comprises a first dual-mode single-cavity unit and a second dual-mode single-cavity unit, the first dual-mode single-cavity A λg/4 strip line is set between the unit and the second dual-mode single-cavity unit; both the first dual-mode single-cavity unit and the second dual-mode single-cavity unit are patch structures, and the patch structure includes an etched cross A patch of a groove line perturbation structure; the first dual-mode single-cavity unit includes a first resonator and a second resonator, and the second dual-mode single-cavity unit includes a third resonator and a fourth resonator. The utility model adopts a single-cavity double-mode box-type topology structure, has multiple coupling paths, and introduces four limited-frequency transmission zero points distributed on both sides of the passband to achieve high selectivity. At the same time, the use of patch structure design can make the bandpass filter body have a high power capacity, which can be applied to the integration of most active devices.

Description

A high-selectivity planar dual-cavity dual-mode chip filter

technical field

The utility model relates to the technical field of electromagnetic fields and microwaves, in particular to a high-selectivity planar double-cavity double-mode chip filter.

Background technique

With the continuous and rapid development of science and technology, the requirements for wireless communication systems (including 5G/E5G) in the fields of military, commerce, and people's livelihood are becoming more and more stringent. As the core device of the wireless communication system, the filter body not only needs to meet the allocation of spectrum resources, filter unwanted signals, and suppress interference signals, but also needs to meet the rapid development needs of miniaturization, high power capacity, high selection, and low cost of wireless communication systems. The physical topology of the filter body, comprehensive design method, design and production process and efficiency, device volume and cost have all put forward stricter requirements. For example, the publication number is CN217719920U "A Dielectric Resonant Structure, Filter Body and Communication Equipment". Therefore, in the face of the increasingly cluttered electromagnetic signal environment and the increasingly tight spectrum allocation resources, it is extremely useful to study filter bodies with high selectivity, high power capacity, miniaturization and low cost to adapt to the rapidly developing wireless communication system. necessary.

In the prior art, the design of the filter body using the substrate integrated waveguide structure can certainly have a high quality factor, but in today's 5G-Sub 6 stage application, there is a problem of excessive size due to the cutoff frequency. The microwave filter body has the advantages of small size and flexible design, but its power capacity is insufficient, which is not conducive to the power demand of the wireless communication system.

Therefore, there is an urgent need for a filter device with small size, high selectivity, large power capacity and low radiation loss.

Contents of the invention

In order to solve the problems of narrow bandwidth, poor selectivity, large volume and high radiation loss of the existing filter body in the 5G-Sub 6 stage, the utility model provides a high-selectivity planar dual-cavity dual-mode patch filter, The fourth-order filter body is designed with a dual-cavity dual-mode chip structure, which can effectively reduce the size of the device and achieve the purpose of miniaturization. It adopts a single-cavity dual-mode box-type topology, has multiple coupling paths, and introduces four finite frequency transmission zeros distributed on both sides of the passband to achieve high selectivity. At the same time, the use of patch structure design can make the bandpass filter body have a high power capacity, which can be applied to the integration of most active devices.

In order to achieve the above purpose, the utility model proposes a high-selectivity planar dual-cavity dual-mode chip filter, including a source feeder, a load feeder and a filter body, and one end of the filter body is connected to a signal source through a source feeder , the other end is connected to a load through a load feeder, the filter body includes a first dual-mode single-cavity unit and a second dual-mode single-cavity unit, and the first dual-mode single-cavity unit and the second dual-mode single-cavity unit are arranged There are λg/4 strip lines; the first dual-mode single-cavity unit and the second dual-mode single-cavity unit are patch structures, and the patch structures include patches etched with cross-groove line disturbance structures;

The first dual-mode single-cavity unit includes a first resonator and a second resonator, and the second dual-mode single-cavity unit includes a third resonator and a fourth resonator.

where λg represents the waveguide wavelength.

Specifically, the bandpass filter body is composed of two dual-mode single-cavity patches, λ _g /4 strip line, SIW electric wall, signal source feeder, and load feeder, and the overall structure is symmetrical.

The four resonators are composed of two dual-cavity and dual-mode patches, each of which uses a cross-groove line perturbation structure, which has the effect of dividing the resonant frequency. The resonators work in TE ₁₀₀ and TE ₀₁₀ modes respectively .

Further, the filter body is provided with a main coupling path and a cross coupling path, the main coupling path includes the simultaneous coupling of the source feeder and the first resonator and the second resonator, and the first resonator and the second resonator The resonators are all coupled to the λg/4 strip line, and the λg/4 strip line is also coupled to the third resonator and the fourth resonator at the same time, and the third resonator and the fourth resonator are both coupled to the load feeder;

The cross-coupling path includes a signal source feeder coupled to a λg/4 stripline, and a λg/4 stripline coupled to a load feeder.

Further, the filter body also includes an upper metal plate, an intermediate dielectric plate and a bottom metal plate, and the upper metal plate is also provided with a SIW electric wall, and the SIW electric wall respectively surrounds the first dual-mode single-cavity unit, the second Two dual-mode single-cavity unit layout;

The upper metal plate and the lower metal plate sandwich the intermediate medium plate.

The filter body has a "sandwich" structure, and the single-layer PCB circuit board printing technology is used in production to realize the filter body production. Among them, the intermediate dielectric board only needs to use a commonly used dielectric substrate, and is more suitable for various application scenarios in the microwave operating frequency band. Therefore, it can meet the needs of miniaturization, low cost, and wide-ranging wireless radio frequency systems. It has high market application value.

The SIW structure can be regarded as an ideal electric wall, which can effectively reduce the radiation loss problem of the chip filter body.

Further, the source feeder and the load feeder include a microstrip line with an impedance of 50Ω.

The microstrip line with an impedance of 50Ω is an international standard feeder, which is more convenient for interconnection and integration with other components.

Further, the λg/4 strip has a zigzag folded structure.

The λg/4 strip line is folded as a whole, connecting the first dual-mode single-cavity unit and the second dual-mode single-cavity unit, which can effectively increase the coupling between the first dual-mode single-cavity unit and the second dual-mode single-cavity unit Strength, broaden the bandwidth of the wideband pass filter body, and the folded design can effectively reduce the volume, making the device miniaturized as a whole; fine-tuning the width and length of the λg/4 strip line can control the first dual-mode single The coupling strength or ratio between the cavity unit and the second dual-mode single-cavity unit can be adjusted to adjust the passband bandwidth or the zero point frequency position of finite frequency transmission.

Through the above technical scheme, the beneficial effects of the utility model are:

1. The utility model adopts a dual-mode dual-cavity patch structure design, and the etching cross-groove line disturbs the degenerate mode of the dual-mode patch, so that it can be used in filter design. In terms of physical characteristics, the fourth-order filter body is designed with two patch cavities, which can effectively reduce the size of the device and achieve the goal of miniaturization. At the same time, the use of patch structure design can make the bandpass filter body have a high power capacity, which can be applied to the integration of most active devices.

2. Adopt the combination of the dual-mode dual-cavity resonant structure of the first dual-mode single-cavity unit and the second dual-mode single-cavity unit with the structure of the source feeder and load feeder, and introduce 4 finite frequencies into the fourth-order filter body Transmission zeros, and two finite frequency transmission zeros are distributed on both sides of the passband. The index of introducing N (N ≥ 2) finite frequency transmission zeros into the N-order filter body is realized, which effectively improves the high selectivity and sideband suppression ability of the band-pass filter body.

3. In the prior art, the coupling between patch cavities generally adopts window gap coupling. This kind of coupling method will cause the filter body to have a narrow bandwidth due to the low current density at the edge of the patch resonator and weak coupling, which limits the its scope of application. The utility model uses the λ _g /4 strip line to directly connect two dual-mode patch cavities, and utilizes the characteristic of weak coupling of the λ _g /4 strip line to effectively increase the frequency of the resonator without affecting the resonance frequency of the resonator. The coupling strength of the two dual-mode patch resonators is increased, and the passband bandwidth can be effectively widened. At the same time, the λg/4 strip line adopts a folded structure design, which can further reduce the device volume. By fine-tuning the width and length of the λg/4 strip line, the pass-band bandwidth and transmission zero point position of the band-pass filter body can be fine-tuned to achieve high selectivity.

4. The first dual-mode single-cavity unit and the second dual-mode single-cavity unit of the present utility model are provided with SIW electric walls. The SIW electric wall can be regarded as an ideal electric wall in this utility model, which can effectively reduce the patch resonator Electromagnetic energy radiation leakage, thus effectively solving the problem of high radiation loss of the chip filter body.

5. The source feeder and load feeder of the present utility model adopt a microstrip line with an impedance of 50Ω, and the filter body structure adopts a planar structure, which is easier to interconnect and integrate with other devices.

Description of drawings

Fig. 1 is a structural representation of a high-selectivity planar dual-cavity dual-mode patch filter of the present invention;

Fig. 2 is a three-dimensional structural schematic diagram of a high-selectivity planar dual-cavity dual-mode patch filter of the present invention;

Fig. 3 is a schematic diagram of the coupling topology of a high-selectivity planar dual-cavity dual-mode patch filter of the present invention;

Fig. 4 is the parameter response curve of the dual-cavity dual-mode patch filter of the utility model embodiment;

Fig. 5 is an example diagram of the adjustable zero point of the limited frequency transmission of the dual-cavity dual-mode patch filter according to the embodiment of the present invention;

Fig. 6 is an example diagram of an adjustable bandwidth of a band-pass filter of a dual-cavity dual-mode patch filter according to an embodiment of the present invention.

The numbers in the attached drawings are: 1 is the signal source feeder, 2 is the load feeder, 3 is the first dual-mode single cavity, 4 is the second dual-mode single cavity, 5 is the λg/4 strip line, and 6 is the first resonator , 7 is the second resonator, 8 is the third resonator, 9 is the fourth resonator, 10 is the upper metal plate, 11 is the middle dielectric plate, 12 is the bottom metal plate, 13 is the SIW electric wall.

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the utility model is further described:

Example 1

As shown in Figures 1 to 3, a high-selectivity planar dual-cavity dual-mode chip filter includes a source feeder 1, a load feeder 2 and a filter body, one end of the filter body is connected to a The signal source and the other end are connected to a load through a load feeder 2, wherein the filter body includes a first dual-mode single-cavity unit 3 and a second dual-mode single-cavity unit 4, and the first dual-mode single-cavity unit 3 and A λg/4 strip line 5 is arranged between the second dual-mode single-cavity unit 4; both the first dual-mode single-cavity unit 3 and the second dual-mode single-cavity unit 4 are patch structures, and the patch structures are etched Perturbed patch structure with cross-groove lines;

The first dual-mode single-cavity unit 3 includes a first resonator 6 and a second resonator 7 , and the second dual-mode single-cavity unit 4 includes a third resonator 8 and a fourth resonator 9 .

Preferably, as shown in Figure 1, the filter body is provided with a main coupling path and a cross coupling path, and the main coupling path includes the simultaneous coupling of the source feeder 1 with the first resonator 6 and the second resonator 7, so Both the first resonator 6 and the second resonator 7 are coupled to the λg/4 stripline 5, and the λg/4 stripline 5 is also coupled to the third resonator 8 and the fourth resonator 9 at the same time, and the first Both the three resonators 8 and the fourth resonator 9 are coupled to the load feeder 2;

The cross-coupling path includes that the source feeder 1 is coupled to the λg/4 stripline 5 , and the λg/4 stripline 5 is coupled to the load feeder 2 .

In Fig. 1, the solid line represents the main coupling path, and the dashed line represents the cross coupling path.

As shown in Figure 2, the filter body also includes an upper metal plate 10, an intermediate dielectric plate 11 and a bottom metal plate 12, the upper metal plate 10 is also provided with SIW electric walls 13, and the SIW electric walls 13 respectively surround The first dual-mode single-cavity unit 3 and the second dual-mode single-cavity unit 4 are arranged;

The upper metal plate 10 and the lower metal plate 12 sandwich the intermediate dielectric plate 11 .

Preferably, the source feeder 1 and the load feeder 2 include a microstrip line with an impedance of 50Ω.

Preferably, the λg/4 strip line 5 has a zigzag folded structure.

In order to verify the performance of the above-mentioned high-selectivity planar dual-cavity dual-mode patch filter (hereinafter referred to as the filter), the following experiments were made:

The parameters of the filter are as follows. The filter includes a dual-mode dual-cavity patch, a source feeder 1, a load feeder 2, a λg/4 strip line 5 and an SIW electric wall 13. The preferred dielectric substrate is Rogers5880, with a relative permittivity of 2.2 and a thickness of 0.508 mm.

In this experiment, as shown in Figure 3, the overall size of the filter is L = 77.5 mm, W = 40 mm; the width of the source feeder 1 and the load feeder 2 is W ₀ = 1.54 mm; the diameter of the metal through hole of the SIW electrical wall 13 is D =0.8 mm; the size of the etched groove line in the dual-mode patch is W ₁ =0.3 mm, L ₁ =24.35 mm, L ₂ =22.00 mm; the width of λ _g /4 strip line 5 is W ₂ =0.56 mm .

Figure 4 shows the simulation results of the above filters. It can be seen from the filter parameter curve that the center frequency is 2.4GHz, the in-band insertion loss is 1.2dB, the in-band reflection loss is about -20dB, and the bandwidth of -3 dB is 170 MHz (relative bandwidth 7.1%). The frequency locations of the four finite frequency transmission zeros are approximately 2.03 GHz, 2.17 GHz, 2.70 GHz and 2.85 GHz. The filter S-parameter plot directly demonstrates the highly selective filter characteristics.

Fig. 5 is an example of regulation of the finite frequency transmission zero point of the above-mentioned filter. It can be seen from FIG. 5 that by adjusting the vector length of the λ _g /4 bar line 5 to adjust the positions of the transmission zero points with limited frequency on both sides, the high selectivity of the above-mentioned filter is further improved.

Figure 6 is an example of the adjustable bandwidth of the above filter. The coupling strength between the first dual-mode single-cavity unit 3 and the second dual-mode single-cavity unit 4 is adjusted by regulating the width of the λ _g /4 strip line 5, so that without changing the patch resonator, The passband bandwidth of the above-mentioned filter is regulated to achieve controllable and adjustable bandwidth. The high selectivity of the filter described above is thus further improved.

The above-described embodiments are only preferred embodiments of the present utility model, and do not limit the scope of implementation of the present utility model, so all equivalent changes or changes made according to the structure, features and principles described in the patent scope of the present utility model Modifications should be included in the patent scope of the utility model application.

Claims (5)

1. A high-selectivity planar dual-cavity dual-mode chip filter, including a source feeder (1), a load feeder (2) and a filter body, one end of the filter body is connected to a The signal source and the other end are connected to a load through a load feeder (2), characterized in that the filter body includes a first dual-mode single-cavity unit (3) and a second dual-mode single-cavity unit (4), and the first dual-mode single-cavity unit (4) A λg/4 strip line (5) is arranged between the single-mode single-cavity unit (3) and the second double-mode single-cavity unit (4); the first double-mode single-cavity unit (3) and the second double-mode single-cavity unit (4) All have a patch structure, and the patch structure includes a patch etched with a cross-groove disturbance structure; The first dual-mode single-cavity unit (3) includes a first resonator (6) and a second resonator (7), and the second dual-mode single-cavity unit (4) includes a third resonator (8) and Fourth resonator (9). 2. A kind of high-selectivity planar dual-cavity dual-mode patch filter according to claim 1 is characterized in that, the filter body is provided with a main coupling path and a cross-coupling path, and the main coupling path includes the The signal source feeder (1) is coupled with the first resonator (6) and the second resonator (7) at the same time, and the first resonator (6) and the second resonator (7) are both connected to the λg/4 bar line (5) coupling, the λg/4 strip line (5) also couples the third resonator (8) and the fourth resonator (9) at the same time, the third resonator (8) and the fourth resonator ( 9) Both are coupled with the load feeder (2); The cross-coupling path includes a signal source feeder (1) coupled to a λg/4 bar line (5), and a λg/4 bar line (5) coupled to a load feeder (2). 3. A high-selectivity planar dual-cavity dual-mode chip filter according to claim 1, characterized in that the filter body also includes an upper metal plate (10), a middle dielectric plate (11) and a bottom layer The metal plate (12), the upper metal plate (10) is also provided with a SIW electric wall (13), and the SIW electric wall (13) respectively surrounds the first dual-mode single-cavity unit (3) and the second dual-mode single-cavity unit (3). Cavity unit (4) layout; The upper metal plate (10) and the lower metal plate (12) sandwich the intermediate medium plate (11). 4. A high-selectivity planar dual-cavity dual-mode patch filter according to claim 1, characterized in that the source feeder (1) and the load feeder (2) both include microstrip lines with an impedance of 50Ω. 5. A high-selectivity planar dual-cavity dual-mode patch filter according to claim 1, characterized in that, the λg/4 strip line (5) has a folded structure in a zigzag shape.

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