阅读说明：本技术 一种5g系统滤波器及其设计方法 (5G system filter and design method thereof ) 是由 罗兵 于 2020-12-15 设计创作，主要内容包括：本发明公开了一种5G系统滤波器及其设计方法,所述5G系统滤波器,包括输入端口、输出端口、多模谐振器、腔体和多个调谐装置,所述输入端口和所述输出端口均与所述多模谐振器相连,所述多模谐振器与多个所述调谐装置设置在所述腔体内,所述调谐装置包括第一调谐装置和第二调谐装置；本发明具有较低的插入损耗和较强的带外抑制能力,能够大大降低带外信号进入接收设备的比例,可以改善5G系统接收设备对有用信号的解调能力,抑制5G系统发射设备对其它系统造成的干扰,大幅度提高接收系统的噪声系数,大幅度提高接收设备的灵敏度,能极大改善5G通信系统的系统容量和通信速率；本发明可广泛应用于滤波器设备技术领域。(The invention discloses a 5G system filter and a design method thereof, wherein the 5G system filter comprises an input port, an output port, a multi-mode resonator, a cavity and a plurality of tuning devices, wherein the input port and the output port are connected with the multi-mode resonator; the invention has lower insertion loss and stronger out-of-band inhibition capability, can greatly reduce the proportion of out-of-band signals entering receiving equipment, can improve the demodulation capability of the receiving equipment of the 5G system to useful signals, inhibits the interference of transmitting equipment of the 5G system to other systems, greatly improves the noise coefficient of the receiving system, greatly improves the sensitivity of the receiving equipment, and can greatly improve the system capacity and the communication rate of the 5G communication system; the invention can be widely applied to the technical field of filter equipment.)

1. A5G system filter is characterized by comprising an input port, an output port, a multi-mode resonator, a cavity and a plurality of tuning devices, wherein the input port and the output port are connected with the multi-mode resonator;

the input port is used for receiving an original signal;

the output port is used for outputting the signal processed by the multimode resonator;

the multi-mode resonator is used for generating a plurality of degenerate modes with resonant frequencies within a 5G system frequency band;

the first tuning device is used for coupling a plurality of degenerate modes generated by the multimode resonator;

the second tuning device is used for controlling the transmission zero of the 5G system filter.

2. The 5G system filter of claim 1, wherein the multimode resonator is a cylindrical dielectric resonator, the cylindrical dielectric resonator adopts a dielectric with 1 magnetic permeability, 0.0002 loss tangent and 24 dielectric constant, and the cylindrical dielectric resonator changes the resonance frequency by adjusting the diameter and height of the cylinder.

3. The filter of claim 1, wherein the first tuning device and the second tuning device are metal screws or dielectric screws; the length of the metal screw or the medium screw is determined by the coupling coefficients of a plurality of degenerate modes; when the first tuning device and the second tuning device are dielectric screws, copper or silver is electroplated on the outer layers of the dielectric screws.

4. The filter of claim 1, wherein the input port and the output port are connected to the multimode resonator by a metal probe; and adjusting the size of input-output coupling by adjusting the size of the metal probe and the position of the metal probe connected with the multimode resonator.

5. The filter of claim 1, wherein the input port and the output port are connected to the multimode resonator by a metal probe having a metal wafer; and adjusting the distance between the metal wafer and the multimode resonator to adjust the input-output coupling.

6. The 5G system filter according to claim 1, further comprising a support block, wherein the support block is a cylindrical dielectric support block, and the resonant frequency of the multimode resonator and the external quality factor of the multimode resonator are determined by setting a height of the cylindrical dielectric support block.

7. A method for designing a 5G system filter according to any one of claims 1 to 6, comprising:

determining a first index of the multimode resonator, wherein the first index comprises a material, a shape size, a resonance frequency, a resonance mode and a coupling coefficient between the resonance modes of the multimode resonator;

simulating by using electromagnetic field simulation software according to the first index to obtain the multimode resonator;

determining a second index of the 5G system filter, wherein the second index comprises a bandwidth, an in-band insertion loss, an in-band return loss, a standing wave ratio and an overall structure of the 5G system filter;

according to the second index, combining the multimode resonator, and performing simulation through advanced radio frequency simulation software to obtain a preliminary simulation result;

and fine-tuning and optimizing the preliminary simulation result to obtain the 5G system filter.

8. The method according to claim 7, wherein the step of determining the first index of the multimode resonator specifically comprises:

setting the multimode resonator into a cylindrical shape, and setting the diameter and the height of the cylindrical shape according to preset sizes;

selecting a corresponding dielectric material according to the frequency band of the 5G system;

determining a resonant frequency and a resonant mode of the multimode resonator by using an open waveguide method, wherein the resonant frequency is in the 5G system frequency band;

establishing a model by using high-frequency electromagnetic field simulation software, and analyzing the electromagnetic field distribution characteristics of each resonance mode of the multimode resonator;

and determining the coupling coefficient among the resonance modes according to the analysis result.

9. The method according to claim 8, wherein the corresponding dielectric material is selected according to the frequency band of the 5G system, specifically:

according to the frequency band of the 5G system, a dielectric material with the magnetic permeability of 1, the loss tangent of 0.0002 and the dielectric constant of 24 is selected.

10. The method according to claim 7, wherein the step of determining the second index of the 5G system filter specifically includes:

setting the bandwidth of the 5G system filter as a 5G frequency band, wherein the in-band insertion loss does not exceed 0.8dB, the in-band return loss exceeds 21dB, and the standing-wave ratio does not exceed 1.299;

determining that the whole structure of the 5G system filter comprises an input port, an output port, a multi-mode resonator, a cavity and a plurality of tuning devices, wherein the input port and the output port are connected with the multi-mode resonator, the multi-mode resonator and the plurality of tuning devices are arranged in the cavity, and the tuning devices comprise a first tuning device and a second tuning device; the input port is used for receiving an original signal; the output port is used for outputting the signal processed by the multimode resonator; the multi-mode resonator is used for generating a plurality of degenerate modes with resonant frequencies within a 5G system frequency band; the first tuning device is used for coupling a plurality of degenerate modes generated by the multimode resonator; the second tuning device is used for controlling the transmission zero of the 5G system filter.

Technical Field

The invention relates to the technical field of filter equipment, in particular to a 5G system filter and a design method thereof.

Background

The filter is one of microwave devices which must be used by the 5G system, plays a key role in the system, can play a role in selecting frequency bands and channels, enables in-band signals to pass through almost without obstruction, can filter out harmonic waves and inhibit stray and other interference signals, and can be said that the normal operation of the 5G system cannot be separated from the filter with excellent performance; at present, various filters exist, such as lumped LC band-pass filters, microstrip filters, cavity filters and the like, but the lumped LC band-pass filters have large size and large insertion loss and are not suitable for filters in high frequency bands; the microstrip filter has low power, and the common single-mode cavity filter has larger size. For the 5G system which is built at present, the frequency band is high, and the frequency resources are in shortage; none of the filters currently used is suitable for 5G systems.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a 5G system filter and a design method thereof.

The technical scheme adopted by the invention is as follows:

in one aspect, an embodiment of the present invention includes a 5G system filter, including an input port, an output port, a multimode resonator, a cavity, and a plurality of tuning devices, where the input port and the output port are both connected to the multimode resonator, the multimode resonator and the plurality of tuning devices are disposed in the cavity, and the tuning devices include a first tuning device and a second tuning device;

the input port is used for receiving an original signal;

the output port is used for outputting the signal processed by the multimode resonator;

the multi-mode resonator is used for generating a plurality of degenerate modes with resonant frequencies within a 5G system frequency band;

the first tuning device is used for coupling a plurality of degenerate modes generated by the multimode resonator, and the first tuning device is one of a plurality of tuning devices;

the second tuning device is used for controlling the transmission zero point of the 5G system filter, and the second tuning device is one of the tuning devices.

Further, the multimode resonator is a cylindrical dielectric resonator, the cylindrical dielectric resonator adopts a dielectric with 1 magnetic permeability, 0.0002 loss tangent and 24 dielectric constant, and the cylindrical dielectric resonator changes the resonance frequency by adjusting the diameter and the height of a cylinder.

Further, the first tuning device and the second tuning device are metal screws or medium screws; the length of the metal screw or the medium screw is determined by the coupling coefficients of a plurality of degenerate modes; when the first tuning device and the second tuning device are dielectric screws, copper or silver is electroplated on the outer layers of the dielectric screws.

Furthermore, the input port and the output port are both connected with the multimode resonator through metal probes; and adjusting the size of input-output coupling by adjusting the size of the metal probe and the position of the metal probe connected with the multimode resonator.

Furthermore, the input port and the output port are both connected with the multimode resonator through a metal probe with a metal wafer; and adjusting the distance between the metal wafer and the multimode resonator to adjust the input-output coupling.

Further, the 5G system filter further includes a supporting block, the supporting block is a cylindrical dielectric supporting block, and the resonant frequency of the multimode resonator and the external quality factor of the multimode resonator are determined by setting the height of the cylindrical dielectric supporting block. On the other hand, the embodiment of the invention includes a design method of a 5G system filter, which includes:

determining a first index of the multimode resonator, wherein the first index comprises a material, a shape size, a resonance frequency, a resonance mode and a coupling coefficient between the resonance modes of the multimode resonator;

simulating by using electromagnetic field simulation software according to the first index to obtain the multimode resonator;

determining a second index of the 5G system filter, wherein the second index comprises a bandwidth, an in-band insertion loss, an in-band return loss, a standing wave ratio and an overall structure of the 5G system filter;

according to the second index, combining the multimode resonator, and performing simulation through advanced radio frequency simulation software to obtain a preliminary simulation result;

and fine-tuning and optimizing the preliminary simulation result to obtain the 5G system filter.

Further, the step of determining the first index of the multimode resonator specifically includes:

setting the multimode resonator into a cylindrical shape, and setting the diameter and the height of the cylindrical shape according to preset sizes;

selecting a corresponding dielectric material according to the frequency band of the 5G system;

determining a resonant frequency and a resonant mode of the multimode resonator by using an open waveguide method, wherein the resonant frequency is in the 5G system frequency band;

establishing a model by using high-frequency electromagnetic field simulation software, and analyzing the electromagnetic field distribution characteristics of each resonance mode of the multimode resonator;

and determining the coupling coefficient among the resonance modes according to the analysis result.

Further, according to the frequency band of the 5G system, selecting a corresponding dielectric material specifically includes:

according to the frequency band of the 5G system, a dielectric material with the magnetic permeability of 1, the loss tangent of 0.0002 and the dielectric constant of 24 is selected.

Further, the step of determining the second indicator of the 5G system filter does not specifically include:

setting the bandwidth of the 5G system filter as a 5G frequency band, wherein the in-band insertion loss does not exceed 0.8dB, the in-band return loss exceeds 21dB, and the standing-wave ratio does not exceed 1.299;

determining that the integral structure of the 5G system filter comprises an input port, an output port, a multi-mode resonator, a cavity and a plurality of tuning devices, wherein the input port and the output port are connected with the multi-mode resonator, and the multi-mode resonator and the plurality of tuning devices are arranged in the cavity; the input port is used for receiving an original signal; the output port is used for outputting the signal processed by the multimode resonator; the multi-mode resonator is used for generating a plurality of degenerate modes with resonant frequencies within a 5G system frequency band; the first tuning device is used for coupling a plurality of degenerate modes generated by the multimode resonator, and the first tuning device is one of a plurality of tuning devices; the second tuning device is used for controlling the transmission zero point of the 5G system filter, and the second tuning device is one of the tuning devices.

The invention has the beneficial effects that:

(1) the 5G system filter comprises a multimode resonator, the multimode resonator has higher power bearing capacity, the 5G system filter has lower insertion loss and stronger out-of-band inhibition capacity, the proportion of out-of-band signals entering receiving equipment can be greatly reduced, the demodulation capacity of the receiving equipment of the 5G system to useful signals can be improved, the interference of transmitting equipment of the 5G system to other systems is inhibited, the noise coefficient of the receiving system is greatly improved, the sensitivity of the receiving equipment is greatly improved, the system capacity and the communication rate of a 5G communication system can be greatly improved, and the experience of people to 5G mobile communication is greatly improved.

(2) The design method of the 5G system filter adopts a mode of combining calculation and simulation, does not use the traditional mode of determining parameters by parameter scanning, can optimize the design target and greatly saves the design time of the 5G system filter.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a schematic structural diagram of a 5G system filter according to the present invention;

fig. 2 is a schematic structural diagram of a multimode resonator according to an embodiment of the invention;

FIG. 3 is a schematic diagram of the electromagnetic field distribution of a cylindrical dielectric resonator embodying the present invention;

fig. 4 is a flowchart illustrating steps of a method for designing a 5G system filter according to an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

In the description of the present invention, it should be understood that the orientation or positional relationship referred to in the description of the orientation, such as the upper, lower, front, rear, left, right, etc., is based on the orientation or positional relationship shown in the drawings, and is only for convenience of description and simplification of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the description of the present invention, the meaning of a plurality of means is one or more, the meaning of a plurality of means is two or more, and larger, smaller, larger, etc. are understood as excluding the number, and larger, smaller, inner, etc. are understood as including the number. If the first and second are described for the purpose of distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present invention, unless otherwise explicitly limited, terms such as arrangement, installation, connection and the like should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above terms in the present invention in combination with the specific contents of the technical solutions.

The embodiments of the present application will be further explained with reference to the drawings.

Referring to fig. 1, an embodiment of the present invention provides a 5G system filter 100, including an input port 101, an output port 102, a multi-mode resonator 103, a cavity 104, and a plurality of tuning devices 105, where the input port 101 and the output port 102 are both connected to the multi-mode resonator 103, the multi-mode resonator 103 and the plurality of tuning devices 105 are disposed in the cavity 104, and the tuning devices 105 include a first tuning device 105-1 and a second tuning device 105-2;

the input port 101 is used for inputting an original signal;

the output port 102 is configured to output a signal processed by the multimode resonator 103;

the multimode resonator 103 is used for generating a plurality of degenerate modes with resonance frequencies within a 5G system frequency band;

the first tuning device 105-1 is configured to couple a plurality of degenerate modes generated by the multimode resonator;

the second tuning means 105-2 is used to control the transmission zero of the 5G system filter.

In this embodiment, the power of the input signal is up to 10W, therefore, the multimode resonator 103 in the 5G system filter 100 is also configured to have a high power-bearing capability, the cavity 104 may be configured as a metal or dielectric rectangular cavity, and all aluminum is plated on the outer surface of the cavity 104, the tuning device 105 passes through one side surface and one top surface of the rectangular cavity and protrudes, and the input port 101 and the output port 102 are both standard impedance-matched (port impedance is 50 Ω) to meet the interconnection standard between the wireless communication system devices; in the present embodiment, the first tuning device 105-1 is configured to couple degenerate modes generated by the multimode resonator to each other; according to the generation mechanism of the transmission zero, namely multipath transmission based on signals, the phases are opposite on some frequencies and mutually offset; in this embodiment, the tuning device (the second tuning device 105-2) on one side of the rectangular cavity is used to control the transmission zero of the 5G system filter, so as to realize the transmission zero on both sides of the passband, improve the out-of-band rejection capability of the filter, improve the anti-interference performance of the system, and improve the reliability of the system. The filter is small, only 28mm x 26mm, and is reduced by about one-half of the size of a single-mode filter.

In this embodiment, the bandwidth of the 5G system filter is 3300 MHz-3600 MHz (relative bandwidth is 2.81%), the in-band insertion loss (IL for short) is less than or equal to 0.8dB, the in-band return loss is less than or equal to 20dB, the out-of-band 50MHz attenuation is 40dB, and the standing-wave ratio is less than or equal to 1.3.

Referring to fig. 2, as an alternative embodiment, the multimode resonator is a cylindrical dielectric resonator, the cylindrical dielectric resonator uses a dielectric having a magnetic permeability of 1, a loss tangent of 0.0002, and a dielectric constant of 24, and the cylindrical dielectric resonator changes a resonance frequency by adjusting a diameter and a height of a cylinder.

In the embodiment, a low-dielectric-constant medium is used for realizing the resonator, specifically, a medium with 1 magnetic permeability, 0.0002 loss tangent and 24 dielectric constant is selected for realizing the resonator and is designed into a cylindrical structure which is easy to process, and a conventional medium body processing method is used, so that the resonator has a stable structure, low processing cost and easy processing; the basic dimensions of the cylindrical dielectric resonator are set to be 21mm in diameter (D) and 9mm in height (H), and the resonant mode and the resonant frequency are determined by using an open waveguide method and analyzed as follows:

as shown in fig. 3, the area inside the metal plate of the cylindrical dielectric resonator placed in the metal shielding box is divided into six areas, the areas 1,2, 3 and 4 have electromagnetic field distribution, and the areas 5 and 6 have weak electromagnetic fields which can be ignored and are regarded as zero field; in the presence of TE waves and TM waves within the dielectric resonator, for example TE waves (TM waves can be analyzed in a similar way), the components of the Hz magnetic field that do not vary with δ in the regions of fig. 1 are obtained by solving the helmholtz equation:

wherein, A1, A2, A3, A4,Are all constants, while:

if H is present_ZThe components are known, the electric field components of the remaining fields can be determined

(8) K in the formula (11) is the wave number of the region in which it is present, inThe propagation constant is β in regions 1 and 4 and j α in regions 2 and 3_i(i ═ 1,2), those TE modes which are independent of θ, their E_z1，E_r，H_θIs zero. Due to H_zIs continuous at the interface of the resonator, so (1) - (4) can be written as:

in the same way, H_r，E_θComprises the following steps:

(12) - (23) formula, J₀(x) And J₁(x) Bessel function of the first kind, K₀(x) And K₁(x) To modify the Bessel function of the second type. In thatOn the boundary, by the boundary condition E of the electric field_θ1＝E_θ4The following can be obtained:

in thatOn the boundary, according to the boundary condition H of the magnetic field_r1＝H_r2The following can be obtained:

in the same way, inOn the boundary, according to the boundary condition H of the magnetic field_r1＝H_r2The following can be obtained:

from formulae (25) to (26), it is possible to obtain:

the formula (26) has a plurality of discrete roots, arranged in size, k₀₁Is the smallest root, so among the modes independent of theta, the lowest-order mode, i.e., the main mode, is TE_01δAnd (5) molding. Different resonant frequencies can be obtained according to different resonant modes, different modes have the same resonant frequency and are called degenerate modes, and the multimode resonator can be realized by utilizing the degenerate modes.

Specifically, the multimode resonator 103 is a cylindrical dielectric resonator that uses a dielectric having a magnetic permeability of 1, a loss tangent of 0.0002, and a dielectric constant of 24, and changes a resonance frequency by adjusting a diameter and a height of a cylinder.

In this embodiment, the multimode resonator 103 is designed as a cylindrical dielectric resonator, and is designed as a cylindrical structure which is easy to process by using a dielectric with 1 magnetic permeability, 0.0002 loss tangent and 24 dielectric constant, and by using a conventional dielectric body processing method, the resonator has a stable structure, low processing cost and easy processing; setting a cylinder with proper diameter and height to generate 2 degenerate modes with frequency within the frequency range of 5G system, and applying proper perturbation to generate coupling among the 2 degenerate modes; and then, the input port and the output port are adjusted to generate coupling with each mode, the coupling coefficient between degenerate modes and the coupling coefficient between the input port and the degenerate mode and the coupling coefficient between the output port and the degenerate mode are adjusted, and an optimized 5G system filter is finally obtained through simulation optimization simulation. Specifically, the dimensions of the cylindrical dielectric resonator are 22.5mm in diameter (D) and 9mm in height (H), and the parameters of the cylindrical dielectric resonator are input into the electromagnetic field simulation software HFSS for modeling simulation, so as to obtain the resonant frequencies of 8 modes and the corresponding quality factors (Q values), specifically, referring to table 1 below, table 1 is a table of the corresponding resonant frequencies of 8 modes and the quality factors (Q values), where the mode 2 and mode 3 frequencies are close and belong to degenerate modes, and as can be seen from table 1, the Q values tend to decrease as the resonant frequencies increase.

Table 18 resonance frequency of mode and its Q value corresponding table

Mode(s)	Resonant frequency	Q value
			Mode 1	3.27791+j0.000120202	13635.1
Mode 2	3032461+j0.000256282	6486.23
			Mode 3	3.51146+j0.000157704	11133.1
Mode 4	3.95993+j0.000386156	5127.37
			Mode 5	4.26947+j7.75782e-05	27517.2
Mode 6	4.29817+j8.94363e-05	24029.2
			Mode 7	4.58991+j0.000123751	18545.0
Mode 8	4.71709+j0.000264259	8925.15

In order to analyze the electromagnetic field distribution characteristics of each mode of the resonator, a high-frequency electromagnetic field simulation software HFSS is used for establishing a model, the electric field distribution of the mode 2 is analyzed, a first tuning device is added, namely, tuning screws are used for changing the electric field characteristic distribution, the mode 2 and the mode 3 are coupled by using a screw scrambling mode, the coupling strength can be controlled by the length of the screws, therefore, the coupling coefficient can be calculated in advance, and then the length of the screws is determined according to the coupling coefficient.

As an optional embodiment, the first tuning device and the second tuning device are metal screws or dielectric screws; the length of the metal screw or the medium screw is determined by the coupling coefficients of a plurality of degenerate modes; when the first tuning device and the second tuning device are dielectric screws, copper or silver is electroplated on the outer layers of the dielectric screws.

In this embodiment, the first tuning device is configured to couple a plurality of degenerate modes generated by the multimode resonator; the first tuning device is a metal screw or a medium screw, the length of the first tuning device is determined by the coupling coefficient required by tuning, the screw can be a cube structure or a cylindrical structure, and when the screw is cylindrical, the diameter of the cylinder can influence the coupling coefficient; when the screw is a cube, the side length of the cube can influence the coupling coefficient; that is, the diameter and side length of the coupling coefficient are determined by the size of the coupling coefficient, but the diameter or side length of the screw cannot be larger than that of the filter cavity. In this embodiment, the number of the first tuning devices may be 1 or more, and the first tuning devices may be applied outside the filter cavity or inside the filter cavity, and the tuning amount may be set according to the requirements of the actual filter.

The second tuning device is mainly used for controlling a transmission zero point and can also be a metal screw or a medium screw; in this embodiment, three transmission zeros are introduced into the 5G system filter, 3 second tuning devices corresponding to the three transmission zeros, one second tuning device is introduced into the bottom surface outside the cavity of the filter, the other two second tuning devices are disposed on the right side and the back of the cavity of the filter, and the second tuning devices realize transmission of zero at a certain frequency point by controlling input to output multi-channel signals, so that transmission zeros outside a passband of the filter are realized, the anti-interference performance of the filter is improved, and the out-of-band rejection capability of the filter is improved. In the embodiment, the transmission zero point is controlled by the second tuning device, so that the final filter has zero points on the left and right sides, the bandwidth is 56MHz, the return loss is less than 21dB, the insertion loss is less than 1dB, and the filter is superior to the filters of the same type; similarly, when the second tuning device employs a dielectric screw, the outer layer of the dielectric screw is typically plated with copper or silver.

As an optional implementation mode, the input port and the output port are both connected with the multimode resonator through metal probes; and adjusting the size of input-output coupling by adjusting the size of the metal probe and the position of the metal probe connected with the multimode resonator.

Or the input port and the output port are both connected with the multimode resonator through a metal probe with a metal wafer; and adjusting the distance between the metal wafer and the multimode resonator to adjust the input-output coupling.

In this embodiment, the coupling between the input port and the output port and the degenerate mode generated by the multimode resonator may be capacitive coupling or magnetic coupling, and the capacitive coupling uses a probe plus metal disc manner, that is, the input port and the output port are both connected to the multimode resonator through a metal probe with a metal disc, and this coupling manner may change the coupling size through the distance between the metal disc and the multimode resonator. The magnetic coupling adopts a mode that a metal probe is connected with the resonator, namely, the input port and the output port are both connected with the multimode resonator through the metal probe, and the coupling size can be adjusted by adjusting the size of the metal probe and the position of the multimode resonator.

As an optional implementation manner, the 5G system filter further includes a supporting block, the supporting block is a cylindrical dielectric supporting block, and the resonant frequency of the multimode resonator and the external quality factor of the multimode resonator are determined by setting the height of the cylindrical dielectric supporting block. In this embodiment, the supporting block may be a cylinder or a cube, the supporting block is made of a ceramic with a low dielectric constant, the dielectric constant is lower than that of the multimode resonator, and the Q value of the multimode resonator may be increased by setting appropriate height and other parameter values because the supporting structure may affect the Q value of the multimode resonator. The size of the support structure also affects the transmission parameters of the 5G system filter.

The 5G system filter provided by the embodiment of the invention has the following technical effects:

the multimode resonator is made of a material with a low dielectric constant, so that the cost of raw materials is reduced; the cavity is made of metal materials, and a common metal CNC machining mode is adopted, so that the machining cost of the metal cavity is reduced; the final design volume of the filter of the 5G system is small, is only 27mm multiplied by 26mm, and is reduced by about one half compared with the volume of a single-mode filter; due to the adoption of the symmetrical structure, the filter is easy to process, and the tuning function is reserved, so that the processed and manufactured 5G system filter can be tuned in a certain range, the design index requirements are completely met, the cost and the reject ratio of batch products are reduced, and the design policy of energy conservation and low carbon is achieved. Meanwhile, the passband of the 5G system filter is in a 5G frequency band, has extremely low insertion loss, small in-band fluctuation, large return loss and small standing wave, is used for a 5G wireless communication system, can greatly reduce out-of-band interference of a 5G system receiver, improves the network capacity of the 5G system, improves the network quality of the 5G system, improves the experience of a user on the 5G system, and greatly promotes the construction and development of a fifth generation wireless communication system.

Referring to fig. 4, an embodiment of the present invention provides a method for designing a 5G system filter, including but not limited to the following steps:

s1, determining a first index of the multimode resonator, wherein the first index comprises a material, a shape and a size, a resonance frequency, a resonance mode and a coupling coefficient between the resonance modes of the multimode resonator;

s2, simulating by using electromagnetic field simulation software according to the first index to obtain the multimode resonator;

s3, determining a second index of the 5G system filter, wherein the second index comprises the bandwidth, the in-band insertion loss, the in-band return loss, the standing wave ratio and the whole structure of the 5G system filter;

s4, according to the second index, combining the multi-mode resonator, and simulating through advanced radio frequency simulation software to obtain a preliminary simulation result;

and S5, fine adjustment and optimization are carried out on the primary simulation result to obtain the 5G system filter.

Step S1, namely the step of determining the first index of the multimode resonator, specifically includes:

s101, setting the multi-mode resonator to be cylindrical, and setting the diameter and the height of the cylindrical according to a preset size;

s102, selecting a corresponding medium material according to the frequency band of the 5G system;

s103, determining the resonant frequency and the resonant mode of the multimode resonator by using an open waveguide method, wherein the resonant frequency is in the frequency band of the 5G system;

s104, establishing a model by using high-frequency electromagnetic field simulation software, and analyzing the electromagnetic field distribution characteristics of each resonance mode of the multimode resonator;

and S105, determining the coupling coefficient among the resonance modes according to the analysis result.

Step S102, namely selecting a corresponding dielectric material according to the frequency band of the 5G system, specifically:

according to the frequency band of the 5G system, a dielectric material with the magnetic permeability of 1, the loss tangent of 0.0002 and the dielectric constant of 24 is selected.

Step S3, that is, the step of determining the second index of the 5G system filter, does not specifically include:

s301, setting the bandwidth of the 5G system filter to be a 5G frequency band, wherein the in-band insertion loss does not exceed 0.8dB, the in-band return loss exceeds 21dB, and the standing-wave ratio does not exceed 1.299;

s302, determining that the integral structure of the 5G system filter comprises an input port, an output port, a multi-mode resonator, a cavity and a plurality of tuning devices, wherein the input port and the output port are connected with the multi-mode resonator, and the multi-mode resonator and the plurality of tuning devices are arranged in the cavity; the input port is used for receiving an original signal; the output port is used for outputting the signal processed by the multimode resonator; the multi-mode resonator is used for generating a plurality of degenerate modes with resonant frequencies within a 5G system frequency band; the first tuning device is used for coupling a plurality of degenerate modes generated by the multimode resonator, and the first tuning device is one of a plurality of tuning devices; the second tuning device is used for controlling the transmission zero point of the 5G system filter, and the second tuning device is one of the tuning devices.

The design method of the 5G system filter provided by the embodiment of the invention has the following technical effects:

the design method of the 5G system filter disclosed by the embodiment of the invention adopts a mode of combining calculation and simulation, and does not use the traditional mode of determining parameters by parameter scanning, so that the design target can be optimized, the design time of the 5G system filter is greatly saved, and the design efficiency is improved.

The embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the gist of the present invention.