Dual-mode bandpass filter based on sectorial patch resonator and design method thereof

Abstract

The application relates to the field of electromagnetic field microwave technology, in particular to a dual-mode band-pass filter based on a fan-shaped patch resonator and a design method thereof. The dual-mode band-pass filter based on the fan-shaped patch resonator of the application adopts a fan-shaped metal patch, thereby exciting the working mode 2 and the working mode 3 in the fan-shaped resonant cavity to simultaneously resonate and serve as the working mode when the filter resonates in a dual-mode. Compared with a traditional dual-mode filter, the application reduces a disturbance structure, makes processing more convenient, and makes the size of the filter smaller. Moreover, the microstrip stepped impedance feed is arranged in parallel, so that simulation test and use connection are more convenient.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electromagnetic field microwave technology, in particular to a dual-mode band-pass filter based on a fan-shaped patch resonator and a design method thereof. BACKGROUND

[0002] In wireless communication and radar systems, a filter is a core component, and the performance of the filter plays an important role in the performance of the entire system. In recent years, in order to meet the higher requirements of modern wireless communication systems on miniaturization, integration and selectivity, more and more scholars pay attention to and conduct in-depth research on the design of filters based on dual-mode microstrip resonators. The design of a microstrip dual-mode filter can further reduce the number of resonators, reduce the size of the filter, and improve the passband selectivity of the filter.

[0003] A conventional microstrip dual-mode filter needs to add a perturbation structure at a proper position on a microstrip resonator to realize dual-resonance modes. The perturbation structure has various shapes, such as a metal via, various-shaped slots, and a small patch. The position of the perturbation structure must be properly selected to separate degenerate modes and couple them together, which leads to a complex structure and a large size of the conventional microstrip dual-mode filter.

[0004] Therefore, there is an urgent need to provide a dual-mode band-pass filter with a small size and a simple structure. SUMMARY

[0005] The present application provides a dual-mode band-pass filter based on a fan-shaped patch resonator and a design method thereof, to solve the technical problem of a large size and a complex structure of a filter in the prior art

[0006] In a first aspect, the present application provides a dual-mode band-pass filter based on a fan-shaped patch resonator, comprising:

[0007] The microstrip patch unit, the dielectric substrate unit and the bottom metal patch unit are arranged in sequence from top to bottom.

[0008] The microstrip patch unit comprises a fan-shaped metal patch and a microstrip feed structure arranged at a feed end of the fan-shaped metal patch.

[0009] The microstrip feed structure comprises a pair of stepped impedance feed lines arranged in parallel.

[0010] Each stepped impedance feed line serves as an input end and an output end of the band-pass filter.

[0011] In a second aspect, the present application provides a design method of a dual-mode band-pass filter based on a fan-shaped patch resonator, comprising:

[0012] Selecting the radius of the fan-shaped metal patch according to the center frequency of the filter.

[0013] After the radius of the fan-shaped metal patch is determined, a central angle θ of the fan-shaped metal patch is calculated according to a center frequency of the filter; and

[0014] According to the external quality factor Q of the filter under different working modes e The change curve determines the position of the feed end and the line width of the stepped impedance feed line.

[0015] The beneficial effects of the present application are that the dual-mode band-pass filter based on the fan-shaped patch resonator of the present application adopts the fan-shaped metal patch, so that the resonant frequency of the main mode of the filter will not change with the angle of the fan-shaped metal patch, compared with the traditional dual-mode filter, the disturbance structure is reduced, the processing is more convenient, and the size of the filter is smaller. And, the parallel stepped impedance microstrip feed makes the simulation test and use connection more convenient.

[0016] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application will be realized and achieved by the structure particularly pointed out in the description and the drawings.

[0017] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are specifically described, and the accompanying drawings are described in detail as follows. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or the prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0019] Figure 1 is a schematic diagram of the three-dimensional structure of the band-pass filter based on the fan-shaped patch resonator of the present application;

[0020] Figure 2 is a schematic diagram of the fan-shaped metal patch of the band-pass filter based on the fan-shaped patch resonator of the present application;

[0021] Figure 3 is Figure 2 is an enlarged schematic diagram of A in FIG.

[0022] Figure 4 is a schematic diagram of the size relationship of the fan-shaped metal patch in the band-pass filter based on the fan-shaped patch resonator of the present application;

[0023] Figure 5This is a coupled topology diagram of the bandpass filter based on a sector patch resonator according to the present invention;

[0024] Figure 6 This is a flowchart illustrating the bandpass filter design method based on a sector patch resonator according to the present invention.

[0025] Figure 7 This is a curve showing the change in the resonant frequency of the sector-shaped metal patch as a function of the central angle of the sector in this invention.

[0026] Figure 8 This is the S-parameter response curve of the filter of the present invention.

[0027] Figure 9 This is a graph showing the external quality factor of the filter in different operating modes of the present invention as a function of the feed position and feed line width.

[0028] In the picture:

[0029] Microstrip patch unit 1, metal via 10, fan-shaped metal patch 11, microstrip feed structure 12, ring-shaped metal sheet 13, dielectric substrate unit 2, bottom metal patch unit 3. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] Example

[0032] like Figures 1 to 3 As shown, this embodiment provides a dual-mode bandpass filter based on a fan-shaped patch resonator, including: a microstrip patch unit 1, a dielectric substrate unit 2, and a bottom metal patch unit 3 arranged sequentially from top to bottom; the microstrip patch unit 1 includes: a fan-shaped metal patch 11 and a microstrip feeding structure 12 disposed at its feeding end; the microstrip feeding structure 12 includes a pair of stepped impedance feed lines arranged in parallel; each of the stepped impedance feed lines serves as the input end and output end of the bandpass filter, respectively.

[0033] In this embodiment, the fan-shaped metal patch 11 is used because of its symmetry. Thus, with the radius unchanged, the resonant frequency of the main mode will not change with the angle, thereby realizing dual-mode resonance. Compared with traditional dual-mode filters, it reduces the disturbance structure, makes the processing more convenient, and makes the filter smaller. Furthermore, the parallel microstrip feeding makes testing and connection more convenient.

[0034] In the embodiment, the external quality factor Q of the fan-shaped patch resonator in the operation mode 2 and the operation mode 3 is determined according to the position of the feeding end and the line width of the stepped impedance feeding line, the microstrip feeding structure is set in the form of stepped impedance, the external coupling is enhanced, and the design freedom is increased while the double-mode resonance is achieved. e Thus, the position of the feeding end and the line width of the stepped impedance feeding line are determined, the design and simulation complexity are reduced while the double-mode resonance is achieved, the microstrip feeding structure is set in the form of stepped impedance, the external coupling is enhanced, and the design freedom is increased.

[0035] In the embodiment, the metal through hole 10 is arranged at the center of the fan-shaped metal patch 11, and the through holes are correspondingly arranged on the dielectric substrate unit 2 and the bottom metal patch unit 3. Specifically, the radius of the metal through hole 10 is 0.1-0.3 mm.

[0036] In the embodiment, the radius of the metal through hole 10 is preferably 0.25 mm, and the radius of the corresponding fan-shaped metal patch 11 is preferably 25 mm. The metal through hole 10 arranged at the center of the fan-shaped metal patch 11 realizes short circuit, the metal through hole 10 serves as the ground end of the fan-shaped metal patch 11, the superior performance of the quarter-wavelength stepped impedance resonator (SIR) is obtained, the disadvantage of the impedance discontinuity of the stepped impedance resonator is overcome, and the size of the filter is further reduced.

[0037] In the embodiment, the annular metal sheet 13 for short circuit of the fan-shaped metal patch 11 is arranged at the metal through hole 10. Specifically, the inner circle radius of the annular metal sheet 13 is 0.2-0.3 mm, and the outer circle radius of the annular metal sheet 13 is 0.4-0.6 mm.

[0038] In the embodiment, the annular metal sheet 13 is used to increase the short circuit effect of the filter, and the inner circle radius of the annular metal sheet 13 is preferably 0.2 mm and the outer circle radius is preferably 0.4 mm.

[0039] In the embodiment, the central angle θ of the fan-shaped metal patch 11 is 30-90°.

[0040] In the embodiment, the central angle θ of the fan-shaped metal patch 11 is preferably 46°, so that the single-cavity double-mode function is met, and the volume of the fan-shaped metal patch 11 is smaller.

[0041] As Figures 4 to 9As shown, the embodiment provides a design method of a dual-mode bandpass filter based on a sector-shaped patch resonator, which comprises: selecting the radius of the sector-shaped metal patch according to the center frequency of the filter; determining the radius of the sector-shaped metal patch, and then calculating the central angle θ of the sector-shaped metal patch according to the center frequency of the filter; and calculating the external quality factor Q of the filter under different working modes according to the center frequency of the filter e The change curve determines the position of the feeding end.

[0042] In the embodiment, the radius of the sector-shaped metal patch 11 is first selected according to the demand and size requirement, then the central angle θ of the sector-shaped metal patch 11 is calculated according to the set radius of the sector-shaped metal patch 11, and then the feeding structure is selected, so that the filter with small size and meeting the dual-mode resonance is obtained.

[0043] In the embodiment, the method for calculating the central angle θ of the sector-shaped metal patch 11 according to the radius of the sector-shaped metal patch 11 comprises: constructing a curve of the resonant frequency of the sector-shaped patch under different working modes changing with the central angle θ of the sector-shaped metal patch 11 through electromagnetic simulation; and selecting the optimal central angle of the sector-shaped metal patch 11 according to the curve.

[0044] Specifically as Figure 8 As shown, in the embodiment, simulation is performed through electromagnetic simulation software, so that the curve of the resonant frequency of the sector-shaped metal patch 11 under different working modes changing with the central angle θ of the sector-shaped metal patch 11 is obtained;

[0045] When the central angle θ of the sector-shaped metal patch 11 gradually increases, the resonant frequency of the working mode 3 decreases with the increase of the central angle θ, and the resonant frequency of the working mode 1 and the resonant frequency of the working mode 2 remain unchanged, until the resonant frequency curve of the working mode 3 and the resonant frequency curve of the working mode 2 intersect, that is, a pair of non-degenerate dual-mode with equal frequency appears at this time, so that the central angle θ of the sector-shaped metal patch 11 when the intersection point appears is determined.

[0046] In the embodiment, the method for calculating the external quality factor Q of the filter under different working modes comprises: constructing a curve of the external quality factor Q of the sector-shaped patch under different working modes changing with the position of the feeding end through electromagnetic simulation; e The method for calculating the position of the feeding end and the line width of the stepped impedance feeding line comprises: constructing a curve of the external quality factor Q of the sector-shaped patch under different working modes changing with the position of the feeding end through electromagnetic simulation; e The method for calculating the position of the feeding end and the line width of the stepped impedance feeding line comprises: constructing a curve of the external quality factor Q of the sector-shaped patch under different working modes changing with the position of the feeding end through electromagnetic simulation;

[0047] Specifically as Figure 9 As shown, in the embodiment, simulation is performed through electromagnetic simulation software, so that the curve of the resonant frequency of the sector-shaped metal patch 11 under different working modes changing with the central angle θ of the sector-shaped metal patch 11 is obtained; eThe intersection position of the mode 2 and the mode 3 is the reasonable feeding end position, that is, the feeding position, wherein the distance between the feeding end and the metal via is D f , and the line width of the step impedance feeding line is W1.

[0048] The extraction formula of the external quality factor is as follows, wherein f0 is the resonance frequency of the current mode phase, f2 is the frequency corresponding to the-90 0 phase, and f1 is the frequency corresponding to the +90 0 phase.

[0049]

[0050] In the embodiment, the theoretical analysis curve is adopted, and the complexity of design and simulation is reduced.

[0051] In conclusion, the dual-mode band-pass filter based on the fan-shaped patch resonator in the application adopts the fan-shaped metal patch 11, and the symmetry is obtained, so that the resonance frequency of the main mode does not change with the angle in the case of the unchanged radius, the dual-mode resonance is realized, the metal via 10 is arranged, the size of the resonator is reduced, the metal via is used as the grounding end of the fan-shaped metal patch, the superior performance of the quarter-wave step impedance resonator (SIR) is obtained, the defect of the step impedance resonator is overcome, and the size of the resonator is further reduced.

[0052] In several embodiments provided in the present application, it should be understood that the disclosed apparatus and method can also be implemented by other means. The apparatus embodiments described above are merely illustrative, for example, the flowcharts and block diagrams in the drawings show the possible implementation architecture, function and operation of the apparatus, method and computer program product according to the embodiments of the present application. In this regard, each block in the flowchart or block diagram can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logic function. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in different order from that shown in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagram and / or flowchart, and the combination of blocks in the block diagram and / or flowchart, can be implemented by a dedicated hardware-based system for performing the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions.

[0053] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first", "second", "third" are only for the purpose of description and cannot be understood as indicating or implying relative importance.

[0054] With the above ideal embodiments according to the present application as the inspiration, through the above description, relevant personnel can make various changes and modifications without deviating from the scope of the technical idea of the present application. The technical scope of the present application is not limited to the contents in the specification, and must be determined by the scope of the claims.

Claims

1. A dual-mode bandpass filter based on a sectoral patch resonator, characterized by, The application relates to a dual-mode band-pass filter. The microstrip patch unit, the dielectric substrate unit and the bottom metal patch unit are arranged from top to bottom. The microstrip patch unit comprises a fan-shaped metal patch and a microstrip feed structure arranged at the feed end of the fan-shaped metal patch. The microstrip feed structure comprises a pair of stepped impedance feed lines arranged in parallel. Each of the stepped impedance feed lines serves as an input end and an output end of a band-pass filter. A metal through hole is arranged at the center of the fan-shaped metal patch, and a through hole is arranged on the dielectric substrate unit and the metal patch unit. The radius of the metal through hole is 0.1-0.3 mm.

2. The dual-mode band-pass filter of claim 1, wherein An annular metal sheet for short-circuiting the fan-shaped metal patch is arranged at the metal through hole.

3. The dual-mode band-pass filter of claim 2, wherein The inner circle radius of the annular metal sheet is 0.2-0.3 mm. The outer circle radius of the annular metal sheet is 0.4-0.6 mm.

4. The dual-mode band-pass filter of claim 1, wherein The central angle of the fan-shaped metal patch is 30-90 degrees.

5. A design method of a dual-mode bandpass filter based on sectoral patch resonators as claimed in claim 1, characterized in that, The application relates to a design method of a dual-mode band-pass filter. The radius of the fan-shaped metal patch is selected according to the center frequency of the filter. After the radius of the fan-shaped metal patch is determined, the central angle of the fan-shaped metal patch is calculated according to the center frequency of the filter. External quality factor Q of a filter under different operating modes e The variation curve determines the position of the feed end and the line width of the stepped impedance feed line.

6. The design method of claim 5, wherein The method for calculating the central angle of the fan-shaped metal patch according to the center frequency of the filter comprises the following steps: A curve of the resonant frequency of the fan-shaped patch under different working modes changing with the central angle of the fan-shaped metal patch is constructed through electromagnetic simulation. The optimal central angle of the fan-shaped metal patch is selected according to the curve.

7. The design method of claim 6, wherein The external quality factor Q of the filter under different operating modes e The method for determining the position of the feed end and the line width of the stepped impedance feed line includes: External quality factor Q of a sectorial patch in different operation modes is constructed by electromagnetic simulation e Curves of the position of the feed end and the line width of the stepped impedance feed line The optimal position and the optimal line width of the feed end are selected according to the curve.

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