Three-dimensional printing coaxial dual-passband filter based on SIR loading type sleeve

Abstract

The invention discloses a three-dimensional printing coaxial dual-passband filter based on an SIR loading type sleeve. The dual-passband filter structurally comprises two waveguide cavity shells, two sleeve resonance units, a rectangular coupling window and two SMA coaxial feed probes. When a signal is input, TEM1A and TEM2A modes of the first waveguide cavity are excited, the signal is coupled to the second waveguide cavity through the coupling window, TEM1B and TEM2B modes of the second waveguide cavity are excited, the TEM1A and TEM1B modes are coupled to form a first passband, the TEM2A and TEM2B modes are coupled to form a second passband, the first passband and the second passband are output through the output port, and the dual-passband effect is achieved. In addition, integrated machining is achieved through the three-dimensional printing technology, and assembly errors are avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of wireless communications, and in particular relates to a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve. Background Art

[0002] With the rapid development of wireless communication technology, high-performance, miniaturized, low-cost, and easy-to-integrate microwave passive devices have emerged to meet various communication technology standards. Due to the limited spectrum resources, the need to filter and manage multiple frequency band signals has become increasingly important. Therefore, dual-passband filters came into being. Dual-passband filters can allow signals in two specific frequency bands to pass through while suppressing signals of other frequencies. This selectivity allows signals of different frequency bands to exist simultaneously in the same system without interfering with each other. At the same time, by eliminating unnecessary frequency components, dual-passband filters can reduce external noise and interference from adjacent channels, thereby improving the quality and reliability of received signals. In modern communication equipment (such as smartphones, wireless base stations, etc.), dual-passband filters can support multiple communication standards (such as LTE, 5G, etc.), allowing users to switch between different networks. Dual-passband filters based on different design methods have also been studied and developed one after another. The traditional dual-passband filter is large in size and weight, and cannot meet the needs of some scenarios. The coaxial dual-passband filter solves the problems of the traditional dual-passband filter and has the advantages of small size, light weight, low insertion loss, and high frequency selectivity. However, the traditional coaxial dual-passband filter has poor independent controllability of the passband, low design freedom, internal and external coupling cannot be easily adjusted, and harmonic suppression needs to be improved. Summary of the invention

[0003] Purpose of the invention: In order to solve the above technical problems, the present invention proposes a method of using three-dimensional printing technology to manufacture a coaxial resonance unit with small size, high harmonic suppression and independently controllable passband, and a dual-passband filter is designed using the resonance unit.

[0004] Technical solution. In order to achieve the above-mentioned purpose, the present invention proposes a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve, the filter comprising a waveguide cavity (1), a sleeve resonance unit (2), a rectangular coupling window (3), an SMA connector feeding probe (4) and a rectangular non-radiative slot (5), wherein the waveguide cavity (1) is cylindrical, the center of the cavity is loaded with a sleeve resonance unit (2), two SMA connector feeding probes (4) are arranged on the side wall of the waveguide cavity (1), and a rectangular non-radiative slot (5) is arranged on the upper and lower walls of the shell of the waveguide cavity (1), and the waveguide cavity (1) comprises a first waveguide cavity (101) and a second waveguide cavity (102), which are coupled and connected through the rectangular coupling window (3).

[0005] Furthermore, the first waveguide cavity (101) and the second waveguide cavity (102) are cylindrical metal cavities.

[0006] Furthermore, the sleeve resonance unit (2) comprises a first sleeve resonance unit and a second sleeve resonance unit; wherein the first sleeve resonance unit comprises a first resonance metal column (201) and a second resonance metal column (202), which are arranged at the center of the first waveguide cavity (101), the two are nested with each other, the second resonance metal column (202) surrounds the first resonance metal column (201), the first resonance metal column (201) is a SIR type structure, the end with a small radius is connected to the outer shell of the first waveguide cavity (101), and the other end is not connected; the second resonance metal column (202) is connected to the outer shell of the first waveguide cavity (101) at the end not connected to the first resonance metal column (201), and the other end is not connected;

[0007] The second sleeve resonance unit comprises a third resonance metal column (203) and a fourth resonance metal column (204), which are arranged at the center of the second waveguide cavity (102) and are nested with each other. The fourth resonance metal column (204) surrounds the third resonance metal column (203). The third resonance metal column (203) is a SIR type structure, and one end with a small radius is connected to the outer shell of the second waveguide cavity (102), while the other end is not connected. The fourth resonance metal column (204) is connected to the outer shell of the second waveguide cavity (102) at the end not connected to the third resonance metal column (203), while the other end is not connected.

[0008] Furthermore, the SMA connector feeding probe (4) comprises a first SMA connector feeding probe (401) and a second SMA connector feeding probe (402); the first SMA connector feeding probe (401) is arranged on the side wall of the first waveguide cavity (101), the probe is fed into the first waveguide cavity (101), and its end is connected to the second resonant metal column (202); the second SMA connector feeding probe (402) is arranged on the side wall of the second waveguide cavity (102), the probe is fed into the second waveguide cavity (102), and its end is connected to the fourth resonant metal column (204).

[0009] Furthermore, the upper and lower walls of the first waveguide cavity (101) are each provided with 12 rectangular non-radiative slots (5), and the upper and lower walls of the second waveguide cavity (102) are evenly provided with 12 rectangular non-radiative slots (5).

[0010] The SMA connector feeding probe (4) comprises a first SMA connector feeding probe (401) and a second SMA connector feeding probe (402). The first SMA connector feeding probe (401) is an input port of a filter channel, and is arranged at the center of a side wall of a first waveguide cavity (101), with a height of h=2.6 mm from the bottom surface, and a probe length of 16.9 mm; the second SMA connector feeding probe (402) is an output port of a filter channel, and is arranged at the center of a side wall of a second waveguide cavity (102), with a height of h=2.8 mm from the bottom surface, and a probe length of 16.9 mm.

[0011] The rectangular coupling window (3) comprises a first rectangular coupling window (301), wherein the first rectangular coupling window (301) is arranged between the first waveguide cavity (101) and the second waveguide cavity (102), the first rectangular coupling window (301) is 12 mm high, and the window width w_w 1 =12.5mm.

[0012] In the present design, coaxial probe feeding is adopted, and the first SMA connector feeding probe (401) is used as an input port to excite different modes. When a signal is input from the first SMA connector feeding probe (401), the TEM of the first waveguide cavity (101) is excited. 1A With TEM 2A mode, the signal is coupled to the second waveguide cavity (102) through the first rectangular coupling window (301), exciting the TEM of the second waveguide cavity (102) 1B With TEM 2B mode, where TEM 1A With TEM 1B The two modes couple to form the first passband, TEM 2A With TEM 2B The two modes are coupled to form a second passband and output through the output port (402). The width of the coupling window can be changed by changing w_w 1 The distance d between the centers of the two sleeves 1 Adjust the strength of the internal coupling, which varies with the coupling window width w_w 1 increases with the increase of the distance d between the centers of the two sleeves. 1 By changing the height h of the two feeding probes s1 With h s2 to adjust the strength of the external coupling, which varies with the height h of the two feeding probes. s1 With h s2 decreases with the increase of .

[0013] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0014] First, the present invention proposes a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve. Compared with the dual-passband filter of the traditional coaxial resonant cavity, a sleeve is added to the outer layer of the resonant metal column close to it, and the metal column is improved to a SIR-loaded structure, which can produce a controllable passband. By changing the height of the sleeve, the center frequency of the second passband can be independently controlled.

[0015] Second, the present invention proposes a 3D printed coaxial dual-passband filter based on a SIR-loaded sleeve with high harmonic suppression characteristics, with a stopband of -20 dB extended to 7.5 times the fundamental frequency, which has never been achieved in coaxial cavity filters.

[0016] Third, a 3D printed coaxial dual-passband filter based on a SIR-loaded sleeve has a high degree of design freedom, and the strength of the internal coupling and the external coupling can be freely and conveniently adjusted. The strength of the internal coupling can be adjusted by changing the coupling window and the center distance of the two sleeves, and the strength of the external coupling can be adjusted by changing the height of the two feeding probes.

[0017] Fourth, the present invention proposes a 3D printed coaxial dual-passband filter based on a SIR-loaded sleeve, which can be processed and formed in one step using 3D printing technology without the need for subsequent debugging, thereby reducing the sensitivity of the resonant cavity to process errors and the impact of assembly errors on the filter performance. The simulation and test results of the S parameters are highly consistent.

[0018] Fifth, the present invention proposes a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve, which has the advantages of miniaturization and lightness compared to the dual-passband filter of the traditional coaxial resonant cavity. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments, and the above and other advantages of the present invention will become more clear.

[0020] Figure 1 This is an overall three-dimensional view of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve of the present invention.

[0021] Figure 2 This is an internal three-dimensional view of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve of the present invention.

[0022] Figure 3 The top view of the three-dimensional printed coaxial dual-passband filter based on the SIR-loaded sleeve of the present invention.

[0023] Figure 4 This is a front view of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to the present invention.

[0024] Figure 5 The topological diagram of the three-dimensional printed coaxial dual-passband filter based on the SIR-loaded sleeve of the present invention.

[0025] Figure 6 The first three mode frequencies of the resonator under HFSS (High Frequency Structure Simulator) simulation of a three-dimensional printed coaxial dual-passband filter based on a SIR loaded sleeve according to the present invention vary with h 2 Change graph, and the change in the frequency ratio of the third mode to the fundamental mode.

[0026] Figure 7 The S-parameter simulation and measured diagram of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve of the present invention.

[0027] Among them, 1-waveguide cavity, 2-sleeve resonance unit, 3-rectangular coupling window, 4-SMA connector feeding probe, 5-rectangular non-radiating slot, 101-first waveguide cavity, 102-second waveguide cavity, 201-first resonant metal column, 202-second resonant metal column, 203-third resonant metal column, 204-fourth resonant metal column, 301-first rectangular coupling window, 401-first SMA connector feeding probe, 402-second SMA connector feeding probe. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] The terms "first", "second" and the like in the specification, claims and the above drawings of the present invention are used to distinguish different objects rather than to describe a specific order.

[0030] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0031] like Figure 1-2As shown, the present invention provides a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve, the filter comprising a waveguide cavity (1), a sleeve resonance unit (2), a rectangular coupling window (3), an SMA connector feeding probe (4) and a rectangular non-radiative slot (5), wherein the waveguide cavity (1) is cylindrical, the center of the cavity is loaded with the sleeve resonance unit (2), two SMA connector feeding probes (4) are arranged on the side wall of the waveguide cavity (1), and the upper and lower walls of the shell of the waveguide cavity (1) are provided with a rectangular non-radiative slot (5), and the waveguide cavity (1) comprises a first waveguide cavity (101) and a second waveguide cavity (102), which are coupled and connected through the rectangular coupling window (3).

[0032] Furthermore, the first waveguide cavity (101) and the second waveguide cavity (102) are cylindrical metal cavities.

[0033] Furthermore, the sleeve resonance unit (2) comprises a first sleeve resonance unit and a second sleeve resonance unit; wherein the first sleeve resonance unit comprises a first resonance metal column (201) and a second resonance metal column (202), which are arranged at the center of the first waveguide cavity (101), the two are nested with each other, the second resonance metal column (202) surrounds the first resonance metal column (201), the first resonance metal column (201) is a SIR type structure, the end with a small radius is connected to the outer shell of the first waveguide cavity (101), and the other end is not connected; the second resonance metal column (202) is connected to the outer shell of the first waveguide cavity (101) at the end not connected to the first resonance metal column (201), and the other end is not connected;

[0034] The second sleeve resonance unit comprises a third resonance metal column (203) and a fourth resonance metal column (204), which are arranged at the center of the second waveguide cavity (102) and are nested with each other. The fourth resonance metal column (204) surrounds the third resonance metal column (203). The third resonance metal column (203) is a SIR type structure, and one end with a small radius is connected to the outer shell of the second waveguide cavity (102), while the other end is not connected. The fourth resonance metal column (204) is connected to the outer shell of the second waveguide cavity (102) at the end not connected to the third resonance metal column (203), while the other end is not connected.

[0035] Furthermore, the SMA connector feeding probe (4) comprises a first SMA connector feeding probe (401) and a second SMA connector feeding probe (402); the first SMA connector feeding probe (401) is arranged on the side wall of the first waveguide cavity (101), the probe is fed into the first waveguide cavity (101), and its end is connected to the second resonant metal column (202); the second SMA connector feeding probe (402) is arranged on the side wall of the second waveguide cavity (102), the probe is fed into the second waveguide cavity (102), and its end is connected to the fourth resonant metal column (204).

[0036] Furthermore, the upper and lower walls of the first waveguide cavity (101) are each provided with 12 rectangular non-radiative slots (5), and the upper and lower walls of the second waveguide cavity (102) are evenly provided with 12 rectangular non-radiative slots (5).

[0037] Figure 3 This is a top view of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to an embodiment of the present invention. The parameters are as follows: 1 =r 5 =1.0,r 2 =r 6 =4.9,r 3 =r 7 =5.4,r 4 =r 8 =7.5,r 9 =r 11 =18.5,r 10 =r 12 =20.5,w_w 1 =12.5,l 1 = l 2 =16.9,d 1 =33.5 (unit: mm). The width of the coupling window can be changed by 1 The distance d between the centers of the two sleeves 1 Adjust the strength of the internal coupling, which varies with the coupling window width w_w 1 increases with the increase of the distance d between the centers of the two sleeves. 1 By changing the height h of the two feeding probes s1 With h s2 to adjust the strength of the external coupling, which varies with the height h of the two feeding probes. s1 With h s2 decreases with the increase of .

[0038] Figure 4 This is a front view of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to an embodiment of the present invention, wherein the parameters are as follows: H1 =H 6 =4.8,H 2 =H 7 =6.7,H 3 =H 8 =10.0,H 4 =12.0,H 5 =15.0,h s1 =2.6,h s2 =2.8 (unit: mm).

[0039] Figure 5 The topology diagram of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to an embodiment of the present invention. When a signal is input from a first SMA connector feeding probe (401), the TEM of the first waveguide cavity (101) is stimulated. 1A With TEM 2A mode, the signal is coupled to the second waveguide cavity (102) through the first rectangular coupling window (301), exciting the TEM of the second waveguide cavity (102) 1B With TEM 2B mode, where TEM 1A With TEM 1B The two modes couple to form the first passband, TEM 2A With TEM 2B The two modes are coupled to form a second passband and are output through the output port of the second SMA connector feeding probe (402).

[0040] Figure 6 The first three mode frequencies of the resonator under HFSS (High Frequency Structure Simulator) simulation of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to an embodiment of the present invention vary with the sleeve height h 2 The change curve diagram and the change of the frequency ratio of the third mode and the fundamental mode. When the sleeve height increases from 5 mm to 10.5 mm, the fundamental mode frequency f 0 Basically remain unchanged, the third mode frequency f 2 From 9.7GHz to 8.6GHz, the secondary mode frequency f 1 From 7.4 GHz down to 4.4 GHz, it can be observed that the secondary mode frequency has relatively good independent controllability, and the frequency ratio f 2 / f 0 It remains unchanged between 7.7 and 8.9 times, which shows that the proposed SIR-loaded sleeve coaxial filter has good harmonic suppression characteristics. By changing the height of the sleeve, the center frequency of the second passband can be independently controlled, and it has good independent controllability.

[0041] Figure 7 The S-parameter simulation and measured diagram of a 3D printed coaxial dual-passband filter based on a SIR-loaded sleeve in an embodiment of the present invention. In the simulation results of this embodiment, the center frequency of channel 1 is 1.0 GHz, the center frequency of channel 2 is 4.5 GHz, the measured 3 dB relative bandwidth is 1.9% and 1.3% respectively, and the in-band return loss is less than 20 dB. The -20 dB stopband of the filter is successfully extended to 7.5 f 0 , with extremely high harmonic suppression performance, three transmission zeros are generated at 1.4GHz, 1.6GHz and 7.1GHz, respectively, which improves the selectivity of the filter. The minimum in-band insertion loss of the two passbands is better than 0.72dB and 0.35dB, respectively, and the return loss is better than 18dB and 19dB, respectively. It can be seen that it has a wider stopband suppression range, lower insertion loss and better selectivity.

[0042] The above is a description of a three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve and a manufacturing method thereof. For those skilled in the art, according to the idea of ​​the embodiment of the present invention, there may be changes in the specific implementation and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

[0043] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve, characterized in that: The filter comprises a waveguide cavity (1), a sleeve resonance unit (2), a rectangular coupling window (3), an SMA connector feeding probe (4) and a rectangular non-radiating slot (5), wherein the waveguide cavity (1) is cylindrical, the center of the cavity is loaded with the sleeve resonance unit (2), two SMA connector feeding probes (4) are arranged on the side wall of the waveguide cavity (1), and the upper and lower walls of the shell of the waveguide cavity (1) are provided with a rectangular non-radiating slot (5), and the waveguide cavity (1) comprises a first waveguide cavity (101) and a second waveguide cavity (102), which are coupled and connected through the rectangular coupling window (3).

2. A three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to claim 1, characterized in that: The first waveguide cavity (101) and the second waveguide cavity (102) are cylindrical metal cavities.

3. A three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to claim 1, characterized in that: The sleeve resonance unit (2) comprises a first sleeve resonance unit and a second sleeve resonance unit; wherein the first sleeve resonance unit comprises a first resonance metal column (201) and a second resonance metal column (202), which are arranged at the center of the first waveguide cavity (101), the two are nested with each other, the second resonance metal column (202) surrounds the first resonance metal column (201), the first resonance metal column (201) is a SIR type structure, the end with a small radius is connected to the outer shell of the first waveguide cavity (101), and the other end is not connected; the second resonance metal column (202) is connected to the outer shell of the first waveguide cavity (101) at the end not connected to the first resonance metal column (201), and the other end is not connected; The second sleeve resonance unit comprises a third resonance metal column (203) and a fourth resonance metal column (204), which are arranged at the center of the second waveguide cavity (102) and are nested with each other. The fourth resonance metal column (204) surrounds the third resonance metal column (203). The third resonance metal column (203) is a SIR type structure, and one end with a small radius is connected to the outer shell of the second waveguide cavity (102), while the other end is not connected. The fourth resonance metal column (204) is connected to the outer shell of the second waveguide cavity (102) at the end not connected to the third resonance metal column (203), while the other end is not connected.

4. A three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to claim 1, characterized in that: The SMA connector feeding probe (4) comprises a first SMA connector feeding probe (401) and a second SMA connector feeding probe (402); the first SMA connector feeding probe (401) is arranged on the side wall of the first waveguide cavity (101), the probe is fed into the first waveguide cavity (101), and the end thereof is connected to the second resonant metal column (202); the second SMA connector feeding probe (402) is arranged on the side wall of the second waveguide cavity (102), the probe is fed into the second waveguide cavity (102), and the end thereof is connected to the fourth resonant metal column (204).

5. A three-dimensional printed coaxial dual-passband filter based on a SIR-loaded sleeve according to claim 1, characterized in that: The upper and lower walls of the first waveguide cavity (101) are each provided with 12 rectangular non-radiative slots (5), and the upper and lower walls of the second waveguide cavity (102) are evenly provided with 12 rectangular non-radiative slots (5).

Images