CN114172484B

CN114172484B - EMI filter-oriented optimization method and EMI filter

Info

Publication number: CN114172484B
Application number: CN202111520313.6A
Authority: CN
Inventors: 李亮; 陈晋玮; 陈坤; 尹红波; 王成; 寇小兵; 张发成; 陈澄
Original assignee: Yangzhou Haike Electronic Technology Co ltd
Current assignee: Yangzhou Haike Electronic Technology Co ltd
Priority date: 2021-12-13
Filing date: 2021-12-13
Publication date: 2022-12-13
Anticipated expiration: 2041-12-13
Also published as: CN114172484A

Abstract

The invention relates to the technical field of filtering, in particular to an EMI filter-oriented optimization method and an EMI filter, which comprises the following steps: s1, selecting a circuit substrate; s2, simulation, namely performing modeling simulation experiment on the selected circuit substrate based on the characteristics of the diode; s3, selecting an experiment once, and selecting an amplitude limiter to perform power test; s4, performing a secondary selection experiment, namely integrating a high-pass filter on a circuit which is connected with the amplitude limiter to perform a power experiment, wherein the high-pass filter adopts an elliptic function type; s5, optimizing parallel design, performing parallel design on the amplitude limiters integrated with the high-pass filters, and performing power test again; s6, integrating experiments, adjusting an access mode according to the experimental result of the optimized parallel design, and performing power test again; and S7, circulating, and optimally designing the filter by adopting the steps, so that the arrival of the corresponding 5G era can be ensured, the noise at the front end of the radio frequency link can be effectively solved, and the filtering effect of the filter is efficiently improved.

Description

Optimization method for EMI filter and EMI filter

Technical Field

The invention relates to the technical field of filtering, in particular to an EMI filter-oriented optimization method and an EMI filter.

Background

The filter is a device for filtering waves, and can be a filter circuit consisting of a capacitor, an inductor and a resistor, so as to effectively remove the frequency point of a specific frequency in a power line or frequencies except the frequency point, namely, the filter can be used for filtering various noise signals to obtain a power signal of the specific frequency or eliminate the power signal of the specific frequency. In the field of Long Term Evolution (LTE), filters such as Surface Acoustic wave filters (saw) and Bulk Acoustic Wave Filters (BAWF) are widely used because of their characteristics of narrow bandwidth, high rejection, low loss, etc. However, in the application of higher frequency, the surface acoustic Wave filter and the bulk acoustic Wave filter may generate the problems of increased passband (passband) loss and decreased stopband (stop band) suppression effect, and the like, and the currently used surface acoustic Wave filter and the bulk acoustic Wave filter cannot meet the requirement of the high-frequency band communication technology of the Millimeter Wave band (Millimeter Wave, mmWave). Therefore, in order to meet the advent of the 5G era, it is difficult to resume the filtering operation using the filter having the conventional configuration in the conventional filter for EMI prevention.

Disclosure of Invention

The invention aims to provide an EMI filter-oriented optimization method and an EMI filter, and solves the problems that in the prior art, the front end of a radio frequency link is greatly influenced by electromagnetism, noise and the like and cannot be efficiently solved.

The purpose of the invention is realized by the following technical scheme, which comprises the following steps: s1, selecting a circuit substrate, wherein the circuit substrate is a microwave stage; s2, performing simulation, namely performing modeling simulation experiments on the selected circuit substrate based on the characteristics of the diodes; s3, a selection experiment is carried out, and an amplitude limiter is selected to carry out power test based on a simulation result; s4, performing a secondary selection experiment, namely integrating a high-pass filter on a circuit which is connected with the amplitude limiter to perform a power experiment, wherein the high-pass filter adopts an elliptic function type; s5, optimizing parallel design, carrying out parallel design on the amplitude limiters integrated with the high-pass filters, and carrying out power test again; s6, integrating experiments, adjusting an access mode according to the experiment result of the optimized parallel design, and performing power test again; and S7, circulating, and repeating the steps S2-S6 until the optimization is completed.

It should be noted that, the applicant adopts the above steps to perform the optimal design of the filter, which can ensure that the noise at the front end of the radio frequency link can be effectively solved and the filtering effect of the filter can be efficiently improved when the corresponding 5G era comes.

The circuit substrate has a dielectric constant of 2.0-2.5 and a tangent loss angle of 0.0008-0.0010.

It should be noted that, the dielectric constant of the present application is set to 2.0-2.5, which can effectively ensure that the standing wave of the filter is less than 1.6.

The S4 specifically comprises the following steps: and selecting a plurality of filtering amplitude limiters for integrating the high-pass filter, wherein the filtering amplitude limiters are manufactured and assembled in a mode of eutectic crystal to a tungsten-copper carrier plate.

It should be noted that, the filter is fabricated and assembled in a eutectic manner to the tungsten copper carrier, so that the assembly and assembly effects of the filter can be ensured.

The S5 specifically comprises the following steps: the limiters with integrated high-pass filters are designed in parallel, and the effective power is increased.

It should be noted that the parallel design can ensure the efficient filtering operation of the filter, which is different from the series design in the prior art.

The S6 specifically comprises the following steps: and manufacturing and assembling all the filters connected in parallel in a mode of eutectic crystal to the tungsten copper carrier plate.

It should be noted that, by performing the eutectic mounting on the tungsten copper carrier, the standing wave size and the suppression effect can be controlled in all directions.

Another aspect of the invention. An EMI filter comprising a filter body, the optimization method according to any one of claims 1 to 5, comprising a capacitor, an inductor and a resistor arranged in the filter body in this order.

It should be noted that the capacitors, the inductors and the resistors are sequentially arranged to efficiently perform the filtering operation, so as to ensure the stability of the filtering operation.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the applicant adopts the steps to carry out the optimal design of the filter, can ensure that the noise at the front end of a radio frequency link can be effectively solved when the corresponding 5G era comes, and the filtering effect of the filter is effectively improved;

2. the dielectric constant of the filter is set to be 2.0-2.5, so that the standing wave of the filter can be effectively ensured to be less than 1.6;

3. the filter is manufactured and assembled in a mode of eutectic crystal to the tungsten copper carrier plate, and the assembly and assembly effects of the filter can be guaranteed.

Drawings

FIG. 1 is a schematic diagram of the experimental results of the present invention;

FIG. 2 is a schematic representation of the results of a further experiment according to the present invention;

FIG. 3 is a schematic flow diagram of the present invention;

FIG. 4 is a graph showing the measurement results of the present invention.

Detailed Description

Referring to fig. 1 to fig. 4, this embodiment provides an optimization method for an EMI filter and an EMI filter, which are mainly used to solve the problem that the front end of a radio frequency link in the prior art is greatly affected by electromagnetic and noise and cannot be efficiently solved.

The specific implementation mode of the invention comprises the following steps: s1, selecting a circuit substrate, wherein the circuit substrate is a microwave stage; s2, simulation, namely performing modeling simulation experiment on the selected circuit substrate based on the characteristics of the diode; s3, a selection experiment is carried out, and an amplitude limiter is selected to carry out power test based on a simulation result; s4, performing a secondary selection experiment, namely integrating a high-pass filter on a circuit which is connected with the amplitude limiter to perform a power experiment, wherein the high-pass filter is in an elliptic function type; s5, optimizing parallel design, performing parallel design on the amplitude limiters integrated with the high-pass filters, and performing power test again; s6, integrating experiments, adjusting an access mode according to the experiment result of the optimized parallel design, and performing power test again; s7, circulating, repeating the steps S2-S6 until the optimization is completed, wherein the dielectric constant of the circuit substrate is 2.2, the tangent loss angle is 0.0009, and S4 specifically comprises the following steps: a plurality of filtering amplitude limiters are selected for integration of the high-pass filter, the filtering amplitude limiters are manufactured and assembled in a mode of eutectic to a tungsten-copper carrier plate, and S5 specifically comprises the following steps: the amplitude limiters integrated with the high-pass filters are designed in parallel, effective power is increased, and S6 specifically comprises the following steps: and manufacturing and assembling all the filters connected in parallel in a mode of eutectic crystal to the tungsten copper carrier plate.

The scheme of the application specifically comprises the following steps: the applicant finds out through practical operations that since the high-pass filter at the front end of the radio frequency link has a great influence on noise, a low-loss design needs to be considered preferentially during design, the loss can be effectively reduced by selecting a lower dielectric loss under the condition of ensuring suppression, and then a circuit substrate with a dielectric constant of 2.2 is selected, wherein the tangent loss angle is only 0.0009, which is completely different from the tangent loss angle of the prior art, and the tangent loss angle of the prior art is generally 0.0015, wherein it needs to be noted that the circuit substrate of the application is in a microwave level, after the circuit substrate is selected, the requirement of a near-end high suppression degree is met by adopting an elliptic function high-pass filter, the detection result is shown in figure 4, and then the applicant carries out modeling simulation design, the method comprises the steps that standing waves in a pass band can meet requirements, wherein in the embodiment, an applicant selects three amplitude limiters, three powers can completely pass through experiments, then the applicant integrates a high-pass filter and then makes three filtering amplitude limiters again, the first two amplitude limiting diodes are assembled in a mode of eutectic crystal to a tungsten-copper carrier plate, one amplitude limiting diode can pass through and two amplitude limiting diodes fail during actual power experiments, then the amplitude limiters can fail after the filters are integrated, the standing waves are too large, power is superposed between the devices, the power is increased, then the applicant designs the amplitude limiters in parallel according to the previous experiment results, the power tolerance is doubled, and the applicant carries out modeling simulation design again according to a new scheme to ensure that the standing waves in the pass band can meet the requirements. According to the operation results of the above embodiment, the embodiment can obtain the following real-time data results, by distinguishing the general design method of the prior art:

it can be clearly obtained from the above table that the technical scheme of the present application can effectively control the standing wave to be less than or equal to 1.6, and can ensure that the loss is only 1.2, which cannot be realized by the prior art, and meanwhile, reference can also be made to the description attached drawings 1 and 2, and it can also be clearly obtained that the technical scheme of the present application is far from being optimized to the prior art.

In another aspect, an EMI filter comprising a filter body, and based on the optimization method of any one of claims 1 to 5, comprising a capacitor, an inductor, and a resistor arranged in the filter body in this order, the applicant can perform the filtering operation with high efficiency.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. An optimization method for an EMI filter, comprising the steps of:

s1, selecting a circuit substrate, wherein the circuit substrate is a microwave stage;

s2, performing simulation, namely performing modeling simulation experiments on the selected circuit substrate based on the characteristics of the diodes;

s3, a selection experiment is carried out, and an amplitude limiter is selected to carry out power test based on a simulation result;

s4, performing a secondary selection experiment, namely integrating a high-pass filter on a circuit which is connected with the amplitude limiter to perform a power experiment, wherein the high-pass filter is in an elliptic function type;

s5, optimizing parallel design, performing parallel design on the amplitude limiters integrated with the high-pass filters, and performing power test again;

s6, integrating experiments, adjusting an access mode according to the experimental result of the optimized parallel design, and performing power test again;

s7, circulating, and repeating the steps S2-S6 until the optimization is completed;

the step S4 is specifically that a plurality of filtering amplitude limiters are selected to integrate the high-pass filter, and the filtering amplitude limiters are manufactured and assembled in a mode of eutectic crystal to a tungsten copper carrier plate; the step S5 is specifically to design the amplitude limiters integrated with the high-pass filters in parallel, and increase the effective power.

2. The method of claim 1, wherein the circuit substrate has a dielectric constant of 2.0-2.5 and a tangent loss angle of 0.0008-0.0010.

3. The optimization method for the EMI filter according to claim 1, wherein the step S6 is specifically to manufacture and assemble all the filters connected in parallel in a manner of eutectic bonding to a tungsten-copper carrier.

4. An EMI filter comprising a filter body, characterized in that the optimization method according to any one of claims 1-3 comprises a capacitor, an inductor and a resistor arranged in sequence in the filter body.