WO2021179758A1

WO2021179758A1 - Filter and dielectric resonator thereof

Info

Publication number: WO2021179758A1
Application number: PCT/CN2020/141021
Authority: WO
Inventors: 谢懿非; 丁海; 林显添
Original assignee: 京信通信技术(广州)有限公司; 京信射频技术(广州)有限公司
Priority date: 2020-03-10
Filing date: 2020-12-29
Publication date: 2021-09-16
Also published as: CN111342187A; CN111342187B

Abstract

The present invention relates to a filter and a dielectric resonator thereof, the dielectric resonator comprising a dielectric block and a metal layer coating the external surface of the dielectric block. The dielectric resonator has a first surface and a second surface arranged to oppose each other, wherein a metalized blind hole is formed on the first surface for a PIN of a radio frequency connector to insert, and a recessed structure different from the metalized blind hole is also formed on the first surface. The forming of the recessed structure on the first surface of the dielectric resonator can have the effect of strengthening the coupling between the RF connector and the dielectric resonator, thereby achieving bandwidth regulation at input and output ends and changing time delay. When the dimension of the recessed structure is increased, the time delay at corresponding input and output ends increases. Therefore, while increasing the depth of the metalized blind hole, the dimension of the recessed structure can be adjusted to make the time delay to meet requirements. When the depth of the metalized blind hole increases, the insertion length of the PIN also increases, and thus the welding strength of the PIN is higher, such that the reliability of the above filter is significantly improved.

Description

Filter and its dielectric resonator

Technical field

The present invention relates to the technical field of filters, in particular to a filter and its dielectric resonator.

Background technique

The filter is an indispensable frequency selection device in communication equipment. With the rapid development of communication systems entering the 5G era, the miniaturization of devices is the key to the development of communication equipment. Since the dielectric waveguide filter has all the characteristics of 5G equipment miniaturization at the same time, it has a wide range of application prospects in 5G communication equipment.

Traditional dielectric waveguide filters usually use radio frequency connectors as signal input and output devices. The inner core of the radio frequency connector is inserted into the metalized blind hole of the dielectric resonator through a PIN needle to achieve coupling. Moreover, the depth of the PIN needle deep into the metal blind hole determines the delay of the input and output ports.

For most filters, in order to meet the port delay requirements, the depth of the PIN needle into the metalized blind hole is generally small. For example, taking the frequency of 2.6GHZ as an example, if the time delay reaches 2.15ns, the depth of the blind hole is only 0.3mm. Because the PIN needle insertion depth is too small, the welding strength of the PIN needle will be affected, resulting in poor reliability of the filter.

Summary of the invention

Based on this, it is necessary to provide a highly reliable filter and its dielectric resonator to solve the problem of poor reliability of the existing dielectric waveguide filter.

In order to solve the above technical problems, the technical solutions are as follows:

A dielectric resonator includes a dielectric block and a metal layer covering the outer surface of the dielectric block. The dielectric resonator has a first surface and a second surface that are arranged opposite to each other. The first surface is formed with a radio frequency connection The first surface of the metalized blind hole into which the PIN needle of the device is inserted is also formed with a concave structure different from the metalized blind hole.

The above technical solutions have at least the following technical effects:

By forming a concave structure on the first surface of the dielectric resonator. Therefore, when the above-mentioned dielectric resonator is matched with the radio frequency connector to form a filter, it can play a role in enhancing the coupling between the radio frequency connector and the dielectric resonator, so as to realize the bandwidth adjustment of the input and output ends of the filter and change Time delay. When the size of the concave structure increases, the corresponding input and output delays increase. Therefore, while increasing the depth of the metallized blind hole, the size of the concave structure can be adjusted to make the time delay meet the demand. As the depth of the metalized blind hole increases, the insertion length of the PIN needle of the radio frequency connector also becomes longer, so the strength of the PIN needle welding is higher, thereby significantly improving the reliability of the resulting filter.

In addition, the present invention also provides a filter. A filter including:

The dielectric resonator according to any one of the above preferred embodiments; and

The radio frequency connector includes a PIN pin inserted in the metalized blind hole and in contact with the hole wall of the metalized blind hole.

By forming a concave structure on the first surface of the dielectric resonator, the coupling between the radio frequency connector and the dielectric resonator can be enhanced, thereby realizing the bandwidth adjustment of the input and output ends and changing the time delay. When the size of the concave structure increases, the time delay of the corresponding input and output ends increases. Therefore, while increasing the depth of the metallized blind hole, the size of the concave structure can be adjusted to make the time delay meet the demand. As the depth of the metalized blind hole increases, the length of the PIN needle insertion becomes longer, so the strength of the PIN needle welding is higher, and the reliability of the above-mentioned filter is significantly improved.

Description of the drawings

FIG. 1 is a schematic diagram of the structure of a filter in a preferred embodiment of the present invention;

Fig. 2 is a top view of a dielectric resonator in the filter shown in Fig. 1;

FIG. 3 is a schematic diagram of the structure of a filter in another embodiment of the present invention;

Fig. 4 is a top view of the dielectric resonator in the filter shown in Fig. 3;

Fig. 5 is a schematic diagram of time delay simulation of the filter shown in Fig. 1;

Fig. 6 is a schematic diagram of time delay simulation of the filter shown in Fig. 1;

Fig. 7 is a schematic diagram of time delay simulation simulation of the filter shown in Fig. 1;

Fig. 8 is a schematic diagram of time delay simulation simulation of a traditional filter;

FIG. 9 is a schematic diagram of time delay simulation simulation of the filter shown in FIG. 1;

FIG. 10 is a schematic diagram of time delay simulation simulation of the filter shown in FIG. 1;

FIG. 11 is a schematic diagram of time delay simulation simulation of the filter shown in FIG. 1;

FIG. 12 is a schematic diagram of time delay simulation simulation of the filter shown in FIG. 1;

Fig. 13 is a schematic diagram of time delay simulation of the filter shown in Fig. 1.

Detailed ways

Please refer to FIG. 1 and FIG. 2. The present invention provides a filter 10 and a dielectric resonator 100. The filter 10 includes the above-mentioned dielectric resonator 100 and a radio frequency connector 200. in:

The dielectric resonator 100 can be used as the first cavity resonator and the last cavity resonator of the filter 10, and the radio frequency connector 200 and the dielectric resonator 100 realize signal coupling to serve as the input port or the output port of the filter 10. Specifically, the radio frequency connector 200 connected to the first cavity resonator serves as the input port of the filter 10, and the radio frequency connector 200 connected to the tail cavity resonator serves as the output port of the filter 10.

It should be pointed out that the dielectric resonator 100 can not only be applied to a filter, but also can be directly applied to a dielectric antenna. Other radio frequency components may also include the above-mentioned dielectric resonator 100 and radio frequency connector 200. Among them, the dielectric resonator 100 and the radio frequency connector 200 cooperate to serve as the transmitting end or the receiving end of microwave signals.

The radio frequency connector 200 includes a PIN pin 221. The PIN pin 221 is used to insert into the dielectric resonator 100 to derive a signal. Specifically in this embodiment, the radio frequency connector 200 further includes a housing 210, an inner core 220, and a PCB board 230. The housing 210 is electrically connected to the PCB board, and the inner core 220 includes the aforementioned PIN pin 221. The housing 210 is generally formed of a good conductor material such as copper and silver. Moreover, an insulation treatment is performed between the inner core 200 and the housing 210 to insulate the PIN needle 221 and the housing 210. The radio frequency connector 200 can adopt a common radio frequency connector on the market, so the structure of the radio frequency connector 200 will not be described in detail.

The dielectric resonator 100 includes a dielectric block 110 and a metal layer 120. The metal layer 120 covers the outer surface of the dielectric block 110. The dielectric block 110 may be formed of insulating materials such as microwave dielectric ceramics to satisfy the smooth propagation of microwave signals in the dielectric block 110. The shape of the dielectric block 110 is generally cubic, which is convenient for processing. The metal layer 120 may be a conductive metal film structure such as a silver layer or a copper layer, and may be formed on the outer surface of the dielectric block 110 by sputtering, evaporation, or the like.

The dielectric resonator 100 has a first surface and a second surface opposite to each other, that is, the left side surface and the right side surface shown in FIG. 1. A metalized blind hole 101 is formed on the first surface, and the metalized blind hole 101 is for inserting the PIN pin 221 of the radio frequency connector 200. When the radio frequency connector 200 is installed, the PCB board 230 is attached to the first surface and is in contact with the metal layer 120, and the PIN pin 221 is inserted into the metalized blind hole 101 and contacts the hole wall of the metalized blind hole. In this way, the housing 210 and the inner core 220 of the radio frequency connector 200 will be respectively connected to the metal layer 120 of the dielectric resonator 100 and the inside of the dielectric block 110 for signal connection, and the radio frequency connector 200 can be used as the signal port of the filter 10 to achieve Import and export of microwave signals.

Specifically, in this embodiment, an annular isolation belt 103 is formed between the hole wall of the metalized blind hole 101 and the metal layer 120.

The hole wall of the metalized blind hole 101 can have the same structure and material as the metal layer 120. After the metal layer 120 is formed, the metal layer 120 can be partially hollowed out by etching, laser engraving, etc., to obtain the isolation belt 103. The isolation tape 103 can be obtained by selective coating. The function of the isolation tape 103 is to separate the metal layer 120 from the hole wall of the metalized blind hole 101 to prevent electrical connection between the two, thereby avoiding the short circuit between the housing 210 of the radio frequency connector 200 and the inner core 220.

In addition, the width of the isolation band 103 will have a certain impact on the frequency of the dielectric resonator 100 and the coupling strength between the radio frequency connector 200 and the dielectric resonator 100. Therefore, in the processing of the filter 10, in order to obtain the required time delay at a specific frequency, it can also be achieved by adjusting the width of the isolation band 103. Moreover, since the metal layer 120 at the edge of the metallized blind hole 101 can be directly etched to change the width of the isolation belt 103, the processing difficulty is small, and the processing can be performed multiple times, so the adjustment is convenient.

It should be pointed out that in other embodiments, the metal layer 120 may be separated from the hole wall of the metalized blind hole 101 by other means such as providing an insulating cushion layer.

Further, a concave structure 102 different from the metalized blind hole 101 is also formed on the first surface. The concave structure 102 may be located at the middle or edge of the first surface, and it refers to two different structures from the metalized blind hole 101. It should be noted that the inner wall of the concave structure 102 is also covered with a metal layer 120.

It is mentioned in the background art that, in order to obtain the required time delay, the insertion depth of the PIN needle is too small in the filter using the traditional pin-type connection, which leads to insufficient welding strength of the PIN needle and relatively low reliability of the filter. Difference. Moreover, because the contact area between the PIN needle and the metallized via is too small, it causes inconvenience in assembly and poor product consistency, which is not conducive to mass production.

As shown in FIG. 8, in a conventional filter, in order to achieve a time delay of 2.15 ns, the depth h _{1 of the} metalized via 101 is only 0.3 mm. It can be seen that the contact area between the metalized via hole and the PIN needle is small, which causes the above-mentioned series of problems.

The arrangement of the concave structure 102 can enhance the coupling strength between the radio frequency connector 200 and the dielectric resonator 100, thereby realizing the bandwidth adjustment of the input port and the output port of the filter 100 to change the time delay. When the size (e.g., depth, width, length, etc.) of the concave structure 102 increases, the time delay of the input port and the output port will also increase accordingly. Therefore, when processing the above-mentioned filter 10 and dielectric resonator 100, the depth of the metalized blind hole 101 can be set to be larger first. In this way, the length of the PIN needle 221 inserted into the metalized blind hole 101 is correspondingly longer, and the contact area of the PIN needle 221 with the hole wall of the metalized blind hole 101 increases. Therefore, the welding strength of the PIN pin 221 is higher, which is beneficial to improve the reliability of the aforementioned filter 10.

Assuming that the time delay does not meet the requirement due to the excessive depth of the metalized blind hole 101, the time delay can be changed by adjusting the size of the concave structure 102 until the time delay meets the requirement. In this way, while meeting the time delay requirement of the filter 100, the purpose of improving the reliability of the filter 10 can be achieved.

Specifically, the model of the filter 10 can be established in the simulation software, the required depth of the metallized blind hole 101 can be set as a fixed parameter, and the volume parameter of the concave structure 102 can be used as a variable parameter. The time delay at the frequency is used as an output result that varies with the volume parameter of the concave structure 102. Then, start the simulation simulation until the output result is the required time delay. At this time, the corresponding volume parameter of the concave structure 102 is the size of the concave structure 102 to be processed.

As shown in FIGS. 9 to 12, under the premise of keeping the time delay constant at 2.15 ns, by providing the concave structure 102, the depth h _{1 of the} metallized via 101 can be at least 0.7 mm. It can be seen that, compared with the conventional filter, the depth h ₁ of the metalized via 101 can be significantly increased while the time delay is inconvenient.

Moreover, since the insertion depth of the PIN needle 221 is correspondingly increased, it is more convenient to weld the PIN needle 221 with the inner wall of the metalized blind hole 101. Moreover, the consistency of the obtained product is good, which is convenient for large-scale production.

In this embodiment, a frequency adjustment hole 104 is formed inwardly on the second surface. Specifically, the frequency adjustment hole 104 may be a round hole, a square hole or a special-shaped hole. The frequency adjustment hole 104 may affect the frequency of the dielectric resonator 100. The smaller the size of the frequency adjustment hole 104, the higher the frequency of the dielectric resonator 100. Therefore, by changing the size of the frequency adjustment hole 104, the frequency of the dielectric resonator 100 can be adjusted.

The so-called time delay is the time delay under a certain frequency. When the size of the concave structure 102 is increased to achieve the required time delay, the frequency of the section dielectric resonator 100 will become lower. At this time, the size of the frequency adjustment hole 104 can be reduced to adjust the frequency back to a specific frequency.

It should be pointed out that in other embodiments, the frequency adjustment hole 104 is not necessary, and the frequency adjustment of the dielectric resonator 100 can also be achieved through a structure such as an external tuning disk.

Further, in this embodiment, the frequency adjustment hole 104 is a circular blind hole or a regular polygonal blind hole. The circular and regular polygonal blind holes have regular shapes and are easy to process, so the production process of the dielectric resonator 100 and the filter 10 can be more convenient. Moreover, since the size of the circular blind hole can _{be accurately characterized by the aperture and depth h 3} , the size of the positive multi-deformation blind hole can be expressed by the side length and depth. Therefore, when the frequency adjustment hole 104 is used to implement frequency adjustment, the size of the frequency adjustment hole 104 is easier to determine and be processed.

Further, in this embodiment, the frequency adjustment hole 104 is located on the second surface opposite to the metalized blind hole 101 and is arranged coaxially with the metalized blind hole 101. In this way, the frequency adjustment hole 104 has higher accuracy when realizing frequency adjustment.

Specifically, in this embodiment, the first surface is an axisymmetric figure, and the symmetry axis of the first surface passes through the center of the metalized blind hole 101 and the concave structure 102.

As shown in FIG. 2 and FIG. 4, for the cube-shaped dielectric block 110, the first table is a rectangle. At this time, the metalized blind hole 101 is arranged at the center of the first surface, and the vertical bisector of one side of the first surface is used as the axis of symmetry and can pass through the center of the concave structure 102. Such an arrangement, on the one hand, facilitates the layout and processing of the dielectric resonator 100; on the other hand, the concave structure 102 has the greatest impact on the coupling strength.

It should be pointed out that in other embodiments, the metalized blind hole 101 and the concave structure 102 are not limited to the above method, as long as it can be ensured that the metalized blind hole 101 and the concave structure 102 are located on the same surface of the dielectric resonator 100. .

The concave structure 102 has many forms, such as a hole, a groove, a sinking platform, etc., as long as it can strengthen the coupling strength between the radio frequency connector 200 and the dielectric resonator 100. Please refer to FIGS. 1 and 2 again. In this embodiment, the concave structure 102 is a sinking platform formed on the edge of the dielectric block 110.

The sinking table can be regarded as a step structure formed by partially cutting the medium 110. At least one sinking platform is provided, and multiple sinking platforms can also be provided along the edge of the dielectric block 110 as required. The size of the sinking platform can be characterized by _{three parameters: length w 1} , width w ₂ and height h _2. Any change in any of the above three parameters can cause the time delay of the dielectric resonator 100 to change.

As shown in Figure 5, when the length w ₁ =5 and the width w ₂ =2 remain unchanged, when the height h ₂ =3, the delay is 3.2 ns; when the height h ₂ =2, the delay is 2.8 ns; When the height h ₂ =1, the time delay is 2.4 ns; when the height h ₂ =0, the time delay is 2.1 ns. Wherein, _{the units of w 1} , w ₂ and h ₂ can be general millimeters, and the above-mentioned numerical values can also only express the proportional relationship between the parameters. It can be seen that as the height h ₂ of the sinking platform increases, the time delay will gradually increase.

As shown in Figure 6, when the height h ₂ =4.5 and the width w ₂ =2 remain unchanged, when the length w ₁ =5, the delay is 3.2 ns; when the length w ₁ =4, the delay is 2.7 ns; When the length w ₁ =3, the delay is 2.5 ns; when the length w ₁ =0, the delay is 2.1 ns. It can be seen that as the length w ₁ of the sinking platform increases, the time delay will gradually increase.

As shown in Figure 7, when the height h ₂ =4.5 and the length w ₁ =4.5 remain unchanged, when the width w ₂ =2.5, the delay is 2.7 ns; when the width w ₂ =2, the delay is 2.4 ns; When the width w ₂ =0, the time delay is 2.1 ns. It can be seen that as the width w ₂ of the sinking platform increases, the time delay will gradually increase.

Therefore, in the process of processing the filter 10, the time delay can be adjusted by changing any one of the length w ₁ , the width w ₂ and the height h ₂ of the sinker or a combination of several parameters, so that the filter 10 While meeting the time delay requirement, it can also ensure that the metalized via 101 has a greater depth.

Further, in this embodiment, two adjacent inner walls of the sinking platform are perpendicular to each other. In other words, the inner wall of the sinking platform is a right-angled surface. Therefore, the volume of the inner space of the sinking platform can be accurately characterized by the product of the _{length w 1} , the width w ₂ and the height h _2. When determining the various dimensions of the sinking platform according to the simulation results, the length w ₁ , the width w ₂ and the height h _{2 are} more convenient to calculate, thereby facilitating the processing of the dielectric resonator 100 and the filter 10.

The following further describes the influence of the _{concave structure 102 on the depth h 1} of the metallized via 101 according to specific simulation data:

As mentioned above, FIG. 8 shows that when the delay of the conventional filter reaches 2.15 ns, the depth h _{1 of the} metalized via 101 = 0.3 mm.

As shown in Figure 9, under the premise of keeping the time delay constant at 2.15 ns, due to the recessed structure 102 sinking platform, the sinking platform can be set to have a depth h ₂ =1 mm, length w ₁ = 2 mm, and width w ₂ = 2mm. At this time, the depth h _{1 of the} metalized via 101 =0.7 mm. It can be seen that the depth of the metalized via 101 is significantly increased compared to the traditional filter, so the PIN pin 221 is welded more firmly.

As shown in Figure 10, under the premise of keeping the time delay unchanged at 2.15ns, continue to change the size of the sinking platform. When the depth h ₂ = 2 mm, the length w ₁ = 2 mm, and the width w ₂ = 2 mm of the _{sinking table are set, the depth h 1 of the} metalized via 101 can reach 0.9 mm.

As shown in Figure 11, under the premise of keeping the time delay constant at 2.15ns, continue to change the size of the sinking platform. _{When the depth h 2 of the} sinking platform is set to be 3 mm, the length w ₁ = 2 mm, and the width w ₂ = 2 mm, the depth h _{1 of the} metalized via 101 can reach 1.1 mm.

As shown in Figure 12, under the premise of keeping the time delay unchanged at 2.15ns, continue to change the size of the sinking platform. When the depth h ₂ = 4 mm, the length w ₁ = 2 mm, and the width w ₂ = 2 mm of the _{sinking table are set, the depth h 1 of the} metalized via 101 can reach 1.3 mm.

3 and 4, in another embodiment of the present invention, the other structure of the dielectric resonator 100 is exactly the same as in the above embodiment, so it will not be repeated here. The difference is that the concave structure 102 is formed by the first surface Blind hole extending to the second surface.

The structure of the blind hole may be the same as that of the frequency adjustment hole 104, and the size of the blind hole may _{be characterized by two parameters of the aperture d 1} and the depth h ₄ , any change of any one of the parameters can cause the time delay of the dielectric resonator 100 to change. Therefore, by setting the aperture d ₁ and the depth h ₄ , the required time delay can be obtained. As shown in Fig. 12, when either of the aperture d ₁ and the depth h ₄ becomes larger, the time delay may increase.

The above-mentioned blind hole as the concave structure 102 may also be a round hole, a square hole or a special-shaped hole. Further, specifically in this embodiment, the blind hole is a circular hole or a regular polygonal hole.

The blind holes of circular and regular polygonal shapes are regular and easy to process, so the production process of the dielectric resonator 100 and the filter 10 can be more convenient. Moreover, since the volume of the internal space of the circular blind hole can _{be accurately characterized by the aperture d 1} and the depth h ₄ , the size of the regular polygonal blind hole can be expressed by the side length and the depth. Therefore, when the size of the blind hole is determined according to the simulation result, the size of the blind hole is easier to determine, thereby further facilitating the processing of the dielectric resonator 100 and the filter 10.

The above-mentioned filter 10 and its dielectric resonator 100, by forming a concave structure 102 on the first surface of the dielectric resonator 100, can play a role in enhancing the coupling between the radio frequency connector 200 and the dielectric resonator 100, thereby realizing input The bandwidth of the output end is adjusted to change the delay. When the size of the concave structure 102 increases, the time delay of the corresponding input and output ends increases. Therefore, while increasing the depth of the metalized blind hole 101, the size of the concave structure 102 can be adjusted to make the time delay meet the demand. As the depth of the metalized blind hole 101 increases, the length of the insertion of the PIN needle 221 also becomes longer, so the welding strength of the PIN needle 221 is higher, and the reliability of the aforementioned filter 10 is significantly improved.

Claims

A dielectric resonator, characterized in that it comprises a dielectric block and a metal layer covering the outer surface of the dielectric block. The dielectric resonator has a first surface and a second surface arranged opposite to each other. The first surface forms There is a metalized blind hole for inserting the PIN needle of the radio frequency connector, and the first surface is also formed with a concave structure different from the metalized blind hole.
The dielectric resonator according to claim 1, wherein the concave structure is a sinker formed on the edge of the dielectric block.
The dielectric resonator according to claim 2, wherein two adjacent inner walls of the sinking platform are perpendicular to each other.
The dielectric resonator according to claim 1, wherein the concave structure is a blind hole extending from the first surface to the second surface.
The dielectric resonator according to claim 4, wherein the blind hole is a circular hole or a regular polygonal hole.
The dielectric resonator according to claim 1, wherein the second surface is recessed inwardly to form a frequency adjustment hole.
The dielectric resonator according to claim 6, wherein the frequency adjustment hole is a circular blind hole or a regular polygonal blind hole.
The dielectric resonator according to claim 6, wherein the frequency adjustment hole is located on the second surface and is arranged opposite to the metalized blind hole, and is arranged coaxially with the metalized blind hole.
The dielectric resonator according to claim 1, wherein a ring-shaped isolation band is formed between the hole wall of the metalized blind hole and the metal layer.
A filter is characterized in that it comprises:

The dielectric resonator according to any one of claims 1 to 9; and

The radio frequency connector includes a PIN pin inserted in the metalized blind hole and in contact with the hole wall of the metalized blind hole.