Miniaturized low-loss millimeter-wave filter and radio-frequency front-end system

Abstract

Disclosed in the present invention are a miniaturized low-loss millimeter-wave filter and a radio-frequency front-end system. The miniaturized low-loss millimeter-wave filter comprises two stacked dielectric substrates, resonators and feed structures, wherein a first metal layer, a second metal layer and a third metal layer are respectively disposed at the top, middle and bottom of the two dielectric substrates; there are at least two resonators, and the at least two resonators are coupled in sequence; and the feed structures include a first feed structure and a second feed structure, the first feed structure and the second feed structure are connected to the resonators located at the head and tail ends, and by means of adjusting the connection positions, the external quality factors of an input end and an output end of the filter are controlled. Compared with conventional micro-strip or LC resonators, the present invention has a higher Q value, and a low loss of the filter can thus be implemented.

Description

A miniaturized low-loss millimeter-wave filter and RF front-end system Technical Field

[0001] This invention relates to the field of communications, and in particular to a miniaturized, low-loss millimeter-wave filter and radio frequency front-end system. Background Technology

[0002] Filters are crucial components of wireless RF front-end systems. Miniaturization and low loss of filters significantly impact the miniaturization, low power consumption, and high efficiency of RF front-end systems. Conventional microstrip or LC lumped element filters have small dimensions, but they can only achieve relatively low Q values, making it difficult to achieve low loss. To address this issue, dielectric integrated waveguide (SIW) resonators can achieve higher Q values; however, SIW resonators are large, leading to large-size filters. With the development of wireless technology, RF front-end systems are trending towards miniaturization, placing higher demands on the miniaturization of filters and other RF components, especially in the millimeter-wave band. RF power amplifiers, switches, low-noise amplifiers, and other front-end circuits are largely integrated into very small chips, making filter miniaturization a critical requirement for integrating with other front-end chips. Summary of the Invention

[0003] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a miniaturized low-loss millimeter-wave filter and radio frequency front-end system.

[0004] The objective of this invention is achieved through the following technical solution:

[0005] A miniaturized low-loss millimeter-wave filter includes two stacked dielectric substrates, a resonator, and a feeding structure. A first metal layer, a second metal layer, and a third metal layer are respectively disposed on the upper surface, middle surface, and lower surface of the two dielectric substrates.

[0006] The number of resonators is at least two, and at least two resonators are coupled sequentially.

[0007] The power supply structure includes a first power supply structure and a second power supply structure. The first power supply structure and the second power supply structure are connected to the resonators located at the beginning and end of the sequential coupling. By adjusting the connection position, the external quality factor of the filter input and output terminals is controlled.

[0008] Furthermore, the resonators have the same structure, each including a metal sheet and a metal through hole. The metal sheet is disposed in the second metal layer, and the metal sheet is connected to the third metal layer through the metal through hole.

[0009] Furthermore, the first and second power supply structures have the same structure, both including an upper metal sheet, a lower metal sheet, and a power supply metal through hole; the upper metal sheet is disposed in the first metal layer, the lower metal sheet is disposed in the second metal layer, and the power supply metal through hole is used to connect the upper metal sheet and the lower metal sheet.

[0010] Furthermore, the lower metal sheet of the first feeding structure is connected to the metal sheet located at the first and second resonators. The coupling amount between the two is controlled by adjusting the connection position, which is the external quality factor of the filter input.

[0011] Furthermore, the lower metal sheet of the second feed structure is connected to the metal sheet located at the last resonator. The amount of coupling between the two is controlled by adjusting the connection position, which is the external quality factor at the output of the filter.

[0012] Furthermore, N resonators can be set between the resonators at both ends to achieve a higher-order filter response or add transmission zeros.

[0013] Furthermore, slots are formed on the first metal layer.

[0014] Furthermore, the first metal layer, the second metal layer, and the third metal layer are connected by metal through-holes.

[0015] Furthermore, the filter has a symmetrical structure.

[0016] A radio frequency front-end system includes the miniaturized low-loss millimeter-wave filter described above.

[0017] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0018] This invention employs a resonator based on metal patches and metal vias, which has a higher Q value than traditional microstrip or LC resonators, thus enabling low-loss filters. Compared to SIW resonators, it has a smaller size while maintaining a high Q value, thus featuring miniaturization and low loss. Attached Figure Description

[0019] Figure 1 is a schematic diagram of a miniaturized low-loss millimeter-wave filter structure according to the present invention;

[0020] Figure 2 is a schematic diagram of the response of a miniaturized low-loss millimeter-wave filter according to the present invention. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0022] Example

[0023] As shown in Figure 1, a miniaturized low-loss millimeter-wave filter includes three metal layers and two dielectric substrates. The two dielectric substrates are stacked close to each other, and a first metal layer, a second metal layer, and a third metal layer are respectively disposed on the upper surface, middle surface, and lower surface of the two dielectric substrates.

[0024] The three metal layers are a first metal layer 1, a second metal layer 2, and a third metal layer 3; the third metal layer 3 is a whole piece of metal floor.

[0025] The entire filter includes a first resonator 4, a second resonator 5, a third resonator 6, a fourth resonator 7, a first feed structure 8, and a second feed structure 9; the first feed structure 8 is connected to the first resonator 4, the first, second, third, and fourth resonators are coupled sequentially, and the fourth resonator 7 is connected to the second feed structure 9.

[0026] The first, second, third and fourth resonators have the same structure, each including a metal sheet and a metal through hole. The metal sheet of the resonator is disposed in the second metal layer and connected to the third metal layer through the metal through hole.

[0027] Furthermore, the size of the resonator's metal plate is used to determine the filter's operating frequency. Generally, the size of the resonator's metal plate located between the first and last resonators is smaller than that of the resonators at the first and last ends.

[0028] The first power supply structure and the second power supply structure include an upper metal sheet, a lower metal sheet, and a power supply metal via; the upper metal sheet is disposed in the first metal layer, the lower metal sheet is disposed in the second metal layer, and the power supply metal via connects the upper and lower metal sheets.

[0029] The lower metal sheet of the first feed structure is connected to the metal sheet of the first resonator. The coupling amount between the first feed structure and the first resonator is controlled by the connection position, which is the external quality factor at the input of the filter. The lower metal sheet of the second feed structure is connected to the metal sheet of the fourth resonator. The coupling amount between the second feed structure and the fourth resonator is controlled by the connection position, which is the external quality factor at the output of the filter.

[0030] A slot 10 is provided on the first metal layer so that the upper metal layer of the first and second power feeding structures is not connected to the outer metal layer of the first metal layer.

[0031] Furthermore, the dimensions of the upper and lower metal sheets in the feed structure are related to the matching performance of the filter.

[0032] The metal plate of the resonator can be rectangular, square, circular, elliptical, or other polygonal shapes.

[0033] The entire filter structure is symmetrical.

[0034] The first, second, third, and fourth resonators may be cross-coupled to generate transmission zeros; the second and third resonators may be omitted to achieve a second-order filter response; or more resonators may be added and coupled to one or more of the first, second, third, or fourth resonators to achieve a higher-order filter response or to increase transmission zeros.

[0035] The first, second and third metal layers are connected by metal through holes, so that the resonator and the feeding structure are surrounded therein.

[0036] The dielectric substrate can be made of high-resistivity silicon wafer, ceramic, or conventional printed circuit board (PCB) material;

[0037] Figure 2 shows the filter response of an embodiment of the present invention. The filter operates in the 37-44GHz range, which can meet the requirements of the 5G millimeter-wave communication band. The return loss is greater than 20dB and the loss is less than 0.5dB. Two transmission zeros are generated at the 29GHz and 30GHz frequencies below the passband, which enhances selectivity.

[0038] This embodiment also provides an RF front-end system, including the miniaturized low-loss millimeter-wave filter.

[0039] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A miniaturized, low-loss millimeter-wave filter, characterized in that, It includes a dielectric substrate with two superimposed layers, a resonator and a feeding structure, wherein a first metal layer, a second metal layer and a third metal layer are respectively disposed on the upper surface, middle surface and lower surface of the two dielectric substrates; The number of resonators is at least two, and at least two resonators are coupled sequentially. The power supply structure includes a first power supply structure and a second power supply structure. The first power supply structure and the second power supply structure are connected to the resonators located at the beginning and end of the sequential coupling. By adjusting the connection position, the external quality factor of the filter input and output terminals is controlled.

2. The miniaturized low-loss millimeter-wave filter according to claim 1, characterized in that, The resonators have the same structure, each including a metal sheet and a metal through hole. The metal sheet is disposed in the second metal layer and is connected to the third metal layer through the metal through hole.

3. The miniaturized low-loss millimeter-wave filter according to claim 2, characterized in that, The first and second power supply structures have the same structure, both including an upper metal sheet, a lower metal sheet, and a power supply metal through hole; the upper metal sheet is disposed in the first metal layer, the lower metal sheet is disposed in the second metal layer, and the power supply metal through hole is used to connect the upper metal sheet and the lower metal sheet.

4. The miniaturized low-loss millimeter-wave filter according to claim 3, characterized in that, The lower metal plate of the first feeding structure is connected to the metal plate located at the first and second resonators. The coupling between the two is controlled by adjusting the connection position, which is the external quality factor of the filter input.

5. The miniaturized low-loss millimeter-wave filter according to claim 3, characterized in that, The lower metal plate of the second feeding structure is connected to the metal plate located at the last resonator. The amount of coupling between the two is controlled by adjusting the connection position, which is the external quality factor at the output of the filter.

6. The miniaturized low-loss millimeter-wave filter according to any one of claims 1-5, characterized in that, By setting N resonators between the first and last resonators, a higher-order filter response can be achieved or a transmission zero can be added.

7. The miniaturized low-loss millimeter-wave filter according to claim 1, characterized in that, A slot is formed on the first metal layer.

8. The miniaturized low-loss millimeter-wave filter according to claim 1, characterized in that, The first metal layer, the second metal layer, and the third metal layer are connected by metal through-holes.

9. The miniaturized low-loss millimeter-wave filter according to claim 1, characterized in that, The filter has a symmetrical structure.

10. A radio frequency front-end system, characterized in that, Including the miniaturized low-loss millimeter-wave filter as described in any one of claims 1-9.

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