Microstrip 5G band-pass filter

Abstract

The micro-strip 5G band-pass filter comprises a metal micro-strip structure arranged on the surface of a dielectric substrate, the metal micro-strip structure comprises a first transmission line and a second transmission line, the first transmission line and the second transmission line are arranged side by side with a coupling branch knot, and the coupling branch knot is symmetrical about the middle axis of the dielectric substrate. The middle part of the first transmission line extends downwards to form a first open-circuit transmission line, the middle part of the second transmission line extends downwards to form a second open-circuit transmission line, and a metal cylinder is arranged at a position, opposite to the central gap, on the coupling branch knot; according to the utility model, the interference of output signals of a WIFI product can be reduced, the size of the filter is reduced, and the product is miniaturized.

Description

Technical Field

[0001] The utility model relates to the technical field of filters, in particular to a microstrip 5G bandpass filter. Background Art

[0002] The rapid development of wireless communication technology is promoting the integration of global information. The ever-expanding amount of information requires communication technology to develop in the direction of high speed, broadband, and large capacity. The demand for communication products from national defense construction and consumer groups has also increased significantly, accompanied by the continuous introduction of new wireless communication products. How to extract specific signals from specific frequency bands has also become a major research direction, in which filters play an important role and have made continuous progress. As modern equipment continues to develop in the direction of portability and high performance, the requirements for filter size and performance are also increasing. How to develop and produce small, high-performance filters has also become an important research field in microwave, radar and other departments.

[0003] Filtering technology is an important branch of signal analysis and processing technology. Whether it is signal acquisition, transmission, or signal processing and exchange, filtering technology is indispensable, and it is crucial to the safe, reliable, effective and flexible transmission of information.

[0004] Among all filters, microstrip transmission lines have superior characteristics such as simple structure, low manufacturing cost, applicability to printed circuit technology, easy combination of active components and easy welding of metal surfaces. At the same time, the application of various new microwave materials has greatly improved the performance of microwave filters, making microstrip line filters the most basic transmission line structure in microwave circuits.

[0005] With the development of wireless communication, the frequency bands used in wireless communication are also increasing. When applying more and higher frequency bands to improve communication speed and bandwidth, new problems will also be introduced. The opening of various frequencies will enrich the frequency band resources and make the interference between frequency bands more serious. In order to reduce the interference of other frequencies and ensure the quality of communication, most communication systems will introduce filters for filtering. Microstrip filters are an important basic type of filters due to their unique structure and easy combination advantages. At present, the most commonly used microstrip filters are parallel coupled line microstrip filters, hairpin microstrip filters, defective ring microstrip filters, etc.; At present, these microstrip filters have the problem of large size, and they do not have advantages when applied to some smaller circuit boards and miniaturization projects, and most of them are low-pass filters and high-pass filters. At the same time, microstrip filters also have the problem of large insertion loss, which will affect the strength of the received signal. Utility Model Content

[0006] In order to solve the problems existing in the prior art, the purpose of the utility model is to provide a microstrip 5G bandpass filter. The utility model can reduce the interference of the output signal of the WIFI product, and reduce the size of the filter to miniaturize the product.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the utility model is: a microstrip 5G bandpass filter, comprising a metal microstrip structure arranged on the surface of a dielectric substrate, the metal microstrip structure comprising a first transmission line and a second transmission line with a central notch arranged side by side with a coupling branch, the coupling branch is symmetrical about the middle axis of the dielectric substrate, the middle part of the first transmission line extends downward to form a first open transmission line, the middle part of the second transmission line extends downward to form a second open transmission line, and a metal cylinder is arranged at a position on the coupling branch opposite to the central notch.

[0008] As a further improvement of the present invention, the middle parts of both ends of the coupling branch are bent upward to form a first bending part, the middle part of the coupling branch is extended upward to form an extension part, and the metal cylinder is arranged on the extension part.

[0009] As a further improvement of the present invention, the width of the coupling branch is 0.2mm, and the distance between the two ends of the coupling branch and the extension portion is 4.2mm, the length of the first bending portion is 2.1mm, the width of the first bending portion is 0.6mm, the length of the extension portion is 1.1mm, and the width of the extension portion is 0.6mm.

[0010] As a further improvement of the present invention, the diameter of the metal cylinder is 0.2 mm.

[0011] As a further improvement of the present invention, the width of the first transmission line and the second transmission line is 0.2 mm, and the distance between the two ends of the first transmission line and the second transmission line is 10 mm.

[0012] As a further improvement of the present invention, the middle portion of the first open-circuit transmission line is bent rightward to form a second bent portion.

[0013] As a further improvement of the present invention, the width of the first open-circuit transmission line is 0.2 mm; the distance between one side of the second bending portion and the first transmission line is 1 mm, and the length between the two opposite sides of the second bending portion is 1.1 mm.

[0014] As a further improvement of the present invention, the length of the second open-circuit transmission line is 1.8 mm, and the width of the second open-circuit transmission line is 1 mm.

[0015] As a further improvement of the present invention, the thickness of the dielectric substrate is 1.6 mm, the plate material is FR4, and its dielectric constant is 4.3.

[0016] The beneficial effects of the utility model are:

[0017] As frequency bands continue to expand and applications become more complex, wireless communication products are increasingly subject to interference. In order to reduce communication interference and increase communication quality, the use of filters has become more common. The filter of the utility model can perform 5G out-of-band filtering for specific 5G communication frequency bands to improve communication quality. For example, the 5G communication frequency band of wifi6 products can use this filter to improve anti-interference capabilities. The size of the filter does not exceed 1cm, which adapts to the current trend of product miniaturization; the filter with a microstrip structure is relatively low in cost, which can increase the competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of an embodiment of the utility model;

[0019] Figure 2 This is a schematic diagram of the dimensions of the filter in the embodiment of the utility model;

[0020] Figure 3 It is a schematic diagram of simulation results of the filter S21 parameters in the embodiment of the utility model;

[0021] Figure 4 Schematic diagram of simulation results of filter S11 parameters in an embodiment of the present utility model.

[0022] Reference numerals:

[0023] 1. dielectric substrate, 2. coupling branch, 3. first transmission line, 4. second transmission line, 5. first open-circuit transmission line, 6. second open-circuit transmission line, 7. metal cylinder, 8. first bending portion, 9. extension portion, 10. second bending portion. DETAILED DESCRIPTION

[0024] The embodiments of the present utility model are described in detail below with reference to the accompanying drawings.

[0025] Example

[0026] like Figure 1As shown, a microstrip 5G bandpass filter comprises a metal microstrip structure arranged on the surface of a dielectric substrate 1, wherein the metal microstrip structure 1 comprises a first transmission line 3 and a second transmission line 4 with a central notch arranged side by side with a coupling branch 2, wherein the coupling branch 2 is symmetrical about the middle axis of the dielectric substrate 1, wherein the middle portion of the first transmission line 3 extends downward to form a first open transmission line 5, and the middle portion of the second transmission line 4 extends downward to form a second open transmission line 6, and a metal cylinder 7 is arranged at a position on the coupling branch 2 opposite to the central notch; the middle portions of both ends of the coupling branch 2 are bent upward to form a first bending portion 8, and the middle portion of the coupling branch 2 extends upward to form an extension portion 9, and the metal cylinder 7 is arranged on the extension portion 9. The middle portion of the first open transmission line 5 is bent rightward to form a second bending portion 10.

[0027] from Figure 1 It can be seen that the metal microstrip structure includes: a first transmission line 3 and a second transmission line 4 with a central notch, and two open transmission lines, namely a first open transmission line 5 and a second open transmission line 6, a coupling branch 2 and a metal cylinder 7; the overall coupling branch 2 is symmetrical about the middle axis of the dielectric substrate 1.

[0028] The specific structure and size of the microstrip filter designed according to the concept of this embodiment are as follows: Figure 2 As shown, Figure 2 The unit of each parameter is millimeter (mm). Specifically, the width of the coupling branch 2 is 0.2mm, and the distance between the two ends of the coupling branch 2 and the extension 9 is 4.2mm. The length of the first bending portion 8 is 2.1mm, the width of the first bending portion 8 is 0.6mm, the length of the extension 9 is 1.1mm, and the width of the extension 9 is 0.6mm. The diameter of the metal cylinder 7 is 0.2mm. The width of the first transmission line 3 and the second transmission line 4 is 0.2mm, and the distance between the two ends of the first transmission line 3 and the second transmission line 4 is 10mm. The width of the first open transmission line 5 is 0.2mm; the distance between one side of the second bending portion 10 and the first transmission line 3 is 1mm, and the length between the opposite sides of the second bending portion 10 is 1.1mm. The length of the second open transmission line 6 is 1.8mm, and the width of the second open transmission line 6 is 1mm.

[0029] The dielectric substrate 1 of this embodiment has a thickness of 1.6 mm, and is made of FR4, with a dielectric constant of 4.3.

[0030] The specific simulation results of the microstrip filter are as follows Figure 3 and Figure 4 As shown by Figure 3 and Figure 4It can be seen that the 3dB bandwidth of the filter S21 is 4.1GHz-6.8GHz, and the return loss S11 between 5GHz-6.8GHz is less than -10dB. From these two parameters, it can be seen that the filter has a good bandpass characteristic in the 5G frequency band.

[0031] The above-mentioned embodiments only express the specific implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model.

Claims

1. A microstrip 5G bandpass filter, characterized in that: The invention comprises a metal microstrip structure arranged on the surface of a dielectric substrate, wherein the metal microstrip structure comprises a first transmission line and a second transmission line with a central notch arranged side by side with a coupling branch, wherein the coupling branch is symmetrical about the middle axis of the dielectric substrate, the middle part of the first transmission line extends downward to form a first open transmission line, the middle part of the second transmission line extends downward to form a second open transmission line, and a metal cylinder is arranged at a position on the coupling branch opposite to the central notch.

2. The microstrip 5G bandpass filter according to claim 1, characterized in that: The middle parts of both ends of the coupling branch are bent upward to form a first bending part, and the middle part of the coupling branch is extended upward to form an extension part, and the metal cylinder is arranged on the extension part.

3. The microstrip 5G bandpass filter according to claim 2, characterized in that: The width of the coupling branch is 0.2 mm, and the distance between the two ends of the coupling branch and the extension portion is 4.2 mm. The length of the first bending portion is 2.1 mm, the width of the first bending portion is 0.6 mm, the length of the extension portion is 1.1 mm, and the width of the extension portion is 0.6 mm.

4. The microstrip 5G bandpass filter according to claim 3, characterized in that: The diameter of the metal cylinder is 0.2 mm.

5. The microstrip 5G bandpass filter according to claim 1, 2, 3 or 4, characterized in that: The width of the first transmission line and the second transmission line is 0.2 mm, and the distance between the two ends of the first transmission line and the second transmission line is 10 mm.

6. The microstrip 5G bandpass filter according to claim 5, characterized in that: The middle portion of the first open-circuit transmission line is bent rightward to form a second bent portion.

7. The microstrip 5G bandpass filter according to claim 6, characterized in that: The width of the first open-circuit transmission line is 0.2 mm; the distance between one side of the second bending portion and the first transmission line is 1 mm, and the length between two opposite sides of the second bending portion is 1.1 mm.

8. The microstrip 5G bandpass filter according to claim 1, characterized in that: The length of the second open transmission line is 1.8 mm, and the width of the second open transmission line is 1 mm.

9. The microstrip 5G bandpass filter according to claim 1, characterized in that: The thickness of the dielectric substrate is 1.6 mm, the plate material is FR4, and its dielectric constant is 4.3.

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