CN108804762B - Design Method of Microwave High Power Multiple Harmonic Filter and Multiple Harmonic Filter - Google Patents

Abstract

The invention discloses a design method of a microwave high-power multiple harmonic filter and the multiple harmonic filter. First, it is simplified into a periodically loaded T branch by the principle of symmetry, and then the equivalent circuit method is used according to the principle of transmission line. The equivalent circuit of the ET branch is obtained, combined with the scattering parameters calculated by the electromagnetic field simulation software, the impedance value of the single harmonic structural element in the high-power multiple harmonic filter is extracted, and then the active impedance and filtering of the single harmonic structural element are used. The attenuation and reflection loss characteristics of the filter can be obtained by the relationship between the characteristics of the filter; this method will simulate the calculation of the high-power multiple harmonic filter, improve the accuracy of engineering design, and at the same time, can greatly shorten the design cycle.

Description

Design Method of Microwave High Power Multiple Harmonic Filter and Multiple Harmonic Filter

technical field

The invention relates to the technical field of microwave high-power transmitters, in particular to a design method of a microwave high-power multiple harmonic filter and a multiple harmonic filter.

Background technique

With the advancement of global informatization, a large amount of information needs to be transmitted through radio frequency and microwave communication equipment, which requires faster transmission speed, wider transmission bandwidth, and stronger anti-interference ability. In these requirements, the filter plays an extremely important role. effect. Especially in the field of high-power microwave applications such as deep space exploration, the role of the filter is more prominent, and the difficulty of development is also greatly improved. The increasing number of communication systems must work normally in the limited spectrum resources, and the spectrum must be allocated according to the demand, so the requirements on the accuracy of the filter selection frequency are more stringent. At the same time, with the development needs of civil communication equipment and military communication equipment, stricter requirements are put forward for filters. Research on high-performance, high-power-capacity harmonic filters is crucial for current high-power microwave communication equipment.

However, the high-power multiple harmonic filter has a complex structure and is difficult to design. Although high-frequency field simulation software can be used to analyze it, it takes a long time to directly use the software to simulate the filter as a whole, and the calculation accuracy is also low. Not too high.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a design method of a microwave high-power multiple harmonic filter and a multiple harmonic filter, which can simplify the simulation calculation of the high-power multiple harmonic filter, improve the accuracy of engineering design, and greatly shorten the Design cycle.

The technical scheme adopted in the present invention is:

A design method of a microwave high-power multiple harmonic filter, comprising the following steps:

Step S1: Carry out theoretical analysis and solution demonstration, and determine the preliminary values of the modular arrays of the harmonic structural units of different frequency bands in the high-power multiple harmonic filter, that is, determine each row of columns of the modular array in the harmonic structural units of each frequency band The specific values of the number m of cylindrical modules and the number n of each column of cylindrical modules, the height of the cylindrical modules, the radial dimension, and the distance between the row and column of cylindrical modules.

Step S2; on the basis of step S1, carry out different frequency band harmonic structural unit modeling and simulation analysis; that is, carry out the overall structural structure modeling of the high-power multiple harmonic filter and the electromagnetic field simulation of S parameters and electric field strength.

Step S3; carry out the concrete structure design of the high-power multiple harmonic filter according to each parameter result obtained in step S2, in conjunction with the current machining accuracy level, the easy implementation mode and the factor that minimizes the influence of the index.

Step S4: On the basis of step S3, assemble a high-power multiple harmonic filter, and perform a small-signal test, a withstand voltage test, and a high-power test.

The step S2 specifically includes the following steps:

Step S2.1: According to the transmission line principle, use the equivalent circuit method to obtain the equivalent circuit diagram of the circuit model of the harmonic structure unit of different frequency bands of the high-power multiple harmonic filter; m columns in each row of the harmonic structure unit of different frequency bands The cylindrical module is equivalent to a series impedance Z, the distance between the centers of the cylindrical modules is L, and the waveguide transmission constant of the module array structure is β.

Step S2.2; for each row of columnar modules in the harmonic structural units of different frequency bands, perform matrix normalization; the normalized matrix A _i is:

in,

Step S2.3; According to the transfer product principle of the cascade network, the equivalent circuit model of the high-power multiple harmonic filter is calculated. The total normalized A matrix is:

Step S2.4; Calculate the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter; The calculation formula of the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter is:

Step S2.5: Calculate the S-parameter obtained by the simulation model of the single-frequency harmonic structural unit through the electromagnetic field simulation software, and the S-parameter will be substituted into the formula (2) to obtain the equivalent impedance Z of each column of cylindrical modules; by the formula (4) and It can be seen from formula (5) that only the equivalent impedance Z of each column of cylindrical modules can be obtained, and the N-th harmonic attenuation characteristics of the harmonic structural units of different frequency bands of the high-power multiple harmonic filter can be obtained.

Step S2.6: Impedance matching is performed between the equivalent circuits of the harmonic structural units of different frequency bands, so as to realize the multi-frequency band harmonic filtering function of the filter.

The multiple harmonic filter designed using the method for designing a microwave high-power multiple harmonic filter according to the above claim is characterized in that: it includes a top assembly, a bottom assembly, a front assembly and a rear assembly, and the top assembly, The bottom component, the front component, and the rear component are all plate-shaped, and both ends of the top component, the bottom component, the front component, and the rear component extend vertically outward to form a part of the rectangular waveguide interface, and the top component and the bottom component The components are exactly the same, the front component and the rear component are exactly the same, and the top component, the bottom component, the front component and the rear component are enclosed together to form a cylindrical shape.

A plurality of unconnected harmonic structure units are distributed on the inner end surfaces of the top component and the bottom component in sequence, and the harmonic structure units arranged on the inner end surfaces of the top component and the bottom component correspond to each other, and the harmonic structure units correspond to each other. The units are all module arrays, and the module arrays all include a plurality of columnar modules arranged in sequence.

There are three harmonic structural units provided on the inner end faces of the top assembly and the bottom assembly, which are respectively the first harmonic structural unit, the second harmonic structural unit and the third harmonic structural unit; the first harmonic structural unit is Module array with 9 rows and 5 columns, including 45 cylindrical modules with rounded top corners; harmonic structure unit 2 is a module array with 9 rows and 11 columns, including 99 cylindrical modules with rounded top corners; harmonic structure unit The third is an array of modules with 7 rows and 16 columns, including 112 cylindrical modules with rounded tops.

In the present invention, a relatively simple method is adopted in the design process of the high-power multiple harmonic filter. First, the symmetry principle is used to simplify the T branch with periodic loading. According to the transmission line principle, the equivalent circuit method is used to obtain the The equivalent circuit of the ET branch is derived, combined with the scattering parameters calculated by the electromagnetic field simulation software, the impedance value of a single harmonic structural element in the high-power multiple harmonic filter is extracted, and then the active impedance of the single harmonic structural element and the filter are used. The attenuation and reflection loss characteristics of the filter can be obtained by using the relationship between the characteristics of the filter; this method will simulate the calculation of the high-power multiple harmonic filter, improve the accuracy of engineering design, and at the same time, can greatly shorten the design cycle.

Description of drawings

Fig. 1 is the flow chart of the present invention;

Fig. 2 is the module array schematic diagram of single harmonic structural unit on single wide surface in the high-power multiple harmonic filter of the present invention;

3 is an equivalent circuit diagram of a single harmonic structural unit in the high-power multiple harmonic filter of the present invention;

4 is a schematic diagram of impedance matching of different harmonic structural units in the high-power multiple harmonic filter according to the present invention;

Fig. 5 is the design and production flow chart of the high-power multiple harmonic filter of the present invention;

6 is a schematic structural diagram of the high-power multiple harmonic filter according to the present invention;

Fig. 7 is the structural representation of multiple harmonic structural units on the bottom assembly in the high-power multiple harmonic filter of the present invention;

Fig. 8 is an enlarged view at a place in Fig. 7;

Fig. 9 is an enlarged view at b in Fig. 7;

FIG. 10 is an enlarged view of c in FIG. 7 .

Detailed ways

As shown in FIG. 1 and FIG. 5 , a design method of a microwave high-power multiple harmonic filter (multi-band harmonic filter) includes the following steps:

Step S1: Carry out theoretical analysis and solution demonstration, and determine the preliminary values of the modular arrays of the harmonic structural units of different frequency bands in the high-power multiple harmonic filter, that is, determine each row of columns of the modular array in the harmonic structural units of each frequency band The specific values of the number m of cylindrical modules and the number n of each column of cylindrical modules, the height of the cylindrical modules, the radial dimension, and the distance between the row and column of cylindrical modules.

As shown in Figure 2, the harmonic structural units of different frequency bands in the high-power multiple harmonic filter are distributed on the upper and lower broad surfaces of the waveguide, and the harmonics of different frequency bands are arranged on the upper and lower broad surfaces of the waveguide. The structural units are the same, and the harmonic structural units are all modular arrays. In each modular array, there are n columnar modules in each column. The value of n is selected according to the harmonic suppression order. There are m columnar modules in each row, and m The value of is selected according to the harmonic suppression degree, and according to the different value combinations of m and n, the harmonic structure unit can achieve different requirements for the harmonic suppression degree in different frequency bands.

Step S2; on the basis of step S1, carry out the modeling and simulation analysis of harmonic structural units in different frequency bands; namely, carry out the overall structure modeling of the high-power multiple harmonic filter and the electromagnetic field simulation of S parameters and electric field strength; specifically including step S2 .1 - Step S2.6.

Step S2.1: According to the transmission line principle, use the equivalent circuit method to obtain the equivalent circuit diagram of the circuit model of the harmonic structure units of different frequency bands of the high-power multiple harmonic filter; as shown in FIG. 3, the harmonic structure units of different frequency bands are obtained. Each row of m cylindrical modules is equivalent to a series impedance Z, the distance between the centers of the cylindrical modules is L, and the waveguide transmission constant of the module array structure is β.

Step S2.2: For each row of columnar modules in the harmonic structural units of different frequency bands, perform matrix normalization; the normalized matrix A _i is:

in,

Step S2.3; According to the transfer product principle of the cascade network, the total normalized A matrix obtained by calculating the equivalent circuit model of the high-power multiple harmonic filter is:

Step S2.4; Calculate the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter; The calculation formula of the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter is:

Step S2.5: Calculate the single frequency band harmonic structural unit simulation model by electromagnetic field simulation software to obtain the S parameter, and the S parameter will be substituted into the formula (2) to obtain the equivalent impedance Z of each column of cylindrical modules; by the formula (4) It can be seen from formula (5) that only the equivalent impedance Z of each column of cylindrical modules can be obtained, and the N-th harmonic attenuation characteristics of the harmonic structural units of different frequency bands of the high-power multiple harmonic filter can be obtained.

Step S2.6: As shown in Figure 4, impedance matching is performed between the equivalent circuits of the harmonic structural units of different frequency bands, so as to realize the multi-frequency band harmonic filtering function of the filter.

Step S3; carry out the concrete structure design of the high-power multiple harmonic filter according to each parameter result obtained in step S2, in conjunction with the current machining accuracy level, the easy implementation mode and the factor that minimizes the influence of the index.

The following is an explanation of the X-band continuous wave 25kW high-power multiple harmonic filter. Due to different structural processes, the requirements for processing materials, the complexity of machining and the electrical properties of the filter itself will have different effects. Considering material stress and For heat dissipation characteristics, red copper is used as the main structural material of the filter; in order to ensure the processing accuracy, the overall structure of the X-band continuous wave 25kW high-power multiple harmonic filter is divided into top component 1, bottom component 2, front component 3 and rear component. 4. Four parts are processed. As shown in Figure 6, the top assembly 1, the bottom assembly 2, the front assembly 3 and the rear assembly 4 are all plate-shaped, the top assembly 1, the bottom assembly 2, the front assembly 3 and the rear assembly. Both ends of 4 extend vertically outward to form a part of the rectangular waveguide interface. The top component 1 and the bottom component 2 are exactly the same, the front component 3 is exactly the same as the rear component 4, the top component 1, the bottom component 2, the front component 3 and the rear component 4 are jointly enclosed to form a tubular shape of the waveguide.

On the inner end surfaces of the top assembly 1 and the bottom assembly 2 are sequentially distributed harmonic structure unit one 5, harmonic structure unit two 6 and harmonic structure unit three 7, harmonic structure unit one 5, harmonic structure unit The second 6 and the third harmonic structure unit 7 are not connected to each other, and the harmonic structure unit one 5, the harmonic structure unit two 6 and the harmonic structure unit three 7 are all modular arrays; as shown in FIG. 7, each harmonic structure unit The cylindrical modules are all cylindrical modules arranged in sequence (not limited to cylindrical modules, but also other structural modules, such as cuboid modules, conical modules, etc.), and the corners of each cylindrical module are rounded, which can be extremely Greatly improve the overall power capacity of the filter.

As shown in Figure 8, Figure 9 and Figure 10, the harmonic structure unit 1 5 is a module array of 9 rows and 5 columns, including 45 cylindrical modules with rounded tops, and the row spacing between the cylindrical modules is equal to The column spacing is a1 and b1 respectively, and the height of the cylindrical module is h1. This unit can suppress the second harmonic. The harmonic structure unit 26 is a module array with 9 rows and 11 columns, including 99 cylinders with rounded tops. The row spacing and column spacing between the cylindrical modules are a2 and b2 respectively, and the height of the cylindrical module is h2. This unit can suppress the third harmonic. The harmonic structure unit 37 is a module array with 7 rows and 16 columns. It contains 112 cylindrical modules with rounded tops. The row and column spacings between the cylindrical modules are a3 and b3, respectively. The height of the cylindrical modules is h3. This unit can suppress the fourth harmonic.

During assembly, the harmonic structure unit 1 5, the harmonic structure unit 2 6 and the harmonic structure unit 3 7 of the top component 1 and the bottom component 2 are buckled on the front component 3 and the rear component 4 in the opposite direction, and each part is fastened with screws. After assembly and tightening, a high-power X-band continuous wave 25kW high-power multiple harmonic filter structure is formed; considering the problems of microwave high-power leakage radiation and high power capacity, after debugging to achieve the expected indicators, it is necessary to The edge of the contact surface of the components is vacuum welded; the final size of the high-power X-band continuous wave 25kW high-power multiple harmonic filter is: 246mm × 68.3mm × 49.2mm.

After preliminary demonstration, a large number of theoretical calculations and electromagnetic field simulation, the current X-band continuous wave 25kW high-power multiple harmonic filter has been processed, assembled, debugged, and welded. After testing, the continuous wave power capacity can reach more than 25KW. Various indicators fully meet the engineering application requirements, and have been successfully applied to a certain type of high-power transmitter equipment in my country, solving an important technical bottleneck for my country's microwave ultra-high-power deep space exploration, and laying a foundation for the follow-up related work. technical basis.

The X-band continuous wave 25kW high-power multiple harmonic filter designed by this method has the following advantages:

High power capacity, continuous wave power capacity can reach more than 25kW; relatively small size, light weight, length, width and height are only 246mm × 68.3mm × 49.2mm, which is of great significance for the miniaturization of super-power transmitter systems; the port adopts standard BJ70 rectangular waveguide Interface, easy to install; good performance indicators, can suppress the second, third and fourth harmonics at the same time, the second harmonic suppression degree is greater than 60dB, the third harmonic suppression degree is greater than 40dB, the fourth harmonic suppression degree is greater than 30dB, extremely The interference of the transmitter to the receiving channel is greatly reduced; three modular array structural units are used, and the impedances between the units are matched, the filter passband insertion loss is less than 0.15dB, and the passband standing wave is less than 1.1, which greatly improves the power capacity of the filter; The structure is simple and novel, the installation is compact, the process difficulty is small, the processing is convenient, and the reliability is high, and it can be widely used in various high-power microwave fields.

The X-band continuous wave 25kW high-power multiple harmonic filter designed by this method enables a certain type of deep space exploration microwave high-power amplifier to output microwave power, through the suppression of multi-band harmonics and the spurious output of the receiving frequency band signal to achieve elimination. Interference to the receiving equipment, thus ensuring that the transmitter does not interfere with the working of the receiving equipment when the transmitter is working with high power.

Step S4: On the basis of step S3, assemble a high-power multiple harmonic filter, and perform a small-signal test, a withstand voltage test, and a high-power test.

After the small signal test, if the index is unqualified, it can be processed again if it has repair value, otherwise it will be scrapped.

After the withstand voltage test, if there is any unqualified phenomenon, it is necessary to evaluate whether it has the value of returning to the furnace, otherwise it will be scrapped.

After the high-power test, if the electric field breakdown phenomenon occurs, further evaluation is required, and if there is a repair value, the surface treatment shall be carried out by mechanical processing, otherwise it shall be scrapped.

To sum up, this patent adopts a relatively simple method in the design process of the high-power multiple harmonic filter. First, it is simplified into a periodically loaded T branch by the principle of symmetry, and the entire filter can be simplified into a Multiple ET branches are connected in series. According to the transmission line principle, the equivalent circuit method is used to obtain the ET branch (ET branch: the waveguide includes the H surface and the E surface, and the ET structure refers to the T-shaped branch on the E surface of the waveguide, which is an industry term). The equivalent circuit, combined with the scattering parameters calculated by the electromagnetic field simulation software, extracts the impedance value of a single harmonic structural element in the high-power multiple harmonic filter, and then uses the relationship between the active impedance of a single harmonic structural element and the filter characteristics. Calculate the attenuation and reflection loss characteristics of the filter; this method will simulate the calculation of high-power multiple harmonic filters, improve the accuracy of engineering design, and at the same time, can greatly shorten the design cycle.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: it is still The technical solutions described in the foregoing embodiments can be modified, or some or all of the technical features thereof can be equivalently replaced; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims (3)

1. a design method of microwave high power multiple harmonic filter, is characterized in that, comprises the steps: Step S1: Carry out theoretical analysis and solution demonstration, and determine the preliminary values of the modular arrays of the harmonic structural units of different frequency bands in the high-power multiple harmonic filter, that is, determine each row of columns of the modular array in the harmonic structural units of each frequency band The specific value of the number of cylindrical modules m and the number of cylindrical modules in each column n, the height of the cylindrical module, the radial dimension and the distance between the row and column of cylindrical modules; Step S2; on the basis of step S1, carry out the modeling and simulation analysis of harmonic structural units in different frequency bands; namely, carry out the overall structural structure modeling of the high-power multiple harmonic filter and the electromagnetic field simulation of S parameters and electric field strength; Step S3; carry out the specific structural design of the high-power multiple harmonic filter according to the results of each parameter obtained in the step S2, in combination with the current machining accuracy level, the easy implementation method, and the factors that minimize the impact on the index; Step S4; on the basis of step S3, assemble a high-power multiple harmonic filter, and perform a small-signal test, a withstand voltage test, and a high-power test; The step S2 specifically includes the following steps: Step S2.1: According to the transmission line principle, use the equivalent circuit method to obtain the equivalent circuit diagram of the circuit model of the harmonic structure unit of different frequency bands of the high-power multiple harmonic filter; m columns in each row of the harmonic structure unit of different frequency bands The shape module is equivalent to a series impedance Z, the distance between the center of the cylindrical module is L, and the waveguide transmission constant of the module array structure is β; Step S2.2: For each row of columnar modules in the harmonic structural units of different frequency bands, perform matrix normalization; the normalized matrix A _i is: in,

Step S2.3: According to the transfer product principle of the cascade network, the total normalized A matrix of the equivalent circuit model of the high-power multiple harmonic filter is calculated as:

Step S2.4; Calculate the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter; The calculation formula of the insertion loss characteristic and the reflection loss characteristic of the high-power multiple harmonic filter is:

Step S2.5: Calculate the S-parameters obtained by the simulation model of the harmonic structural unit of a single frequency band by the electromagnetic field simulation software, and the S-parameters will be substituted into the formula (2) to obtain the equivalent impedance Z of each column of cylindrical modules; by the formula (4) and It can be seen from formula (5) that only the equivalent impedance Z of each column of cylindrical modules is required, and the N-th harmonic attenuation characteristics of the harmonic structural units of different frequency bands of the high-power multiple harmonic filter can be obtained; Step S2.6: Impedance matching is performed between equivalent circuits of harmonic structural units of different frequency bands, so as to realize the multi-frequency band harmonic filtering function of the filter. 2. the multiple harmonic filter designed by the design method of the microwave high power multiple harmonic filter described in the above claim 1, is characterized in that: comprise top assembly, bottom assembly, front assembly and rear assembly, The top component, the bottom component, the front component, and the rear component are all plate-shaped, and both ends of the top component, the bottom component, the front component, and the rear component extend vertically outward to form a part of the rectangular waveguide interface. The components are exactly the same as the bottom component, the front component and the rear component are exactly the same, and the top component, the bottom component, the front component and the rear component are enclosed together to form a cylindrical shape; A plurality of unconnected harmonic structure units are distributed on the inner end surfaces of the top component and the bottom component in sequence, and the harmonic structure units arranged on the inner end surfaces of the top component and the bottom component correspond to each other, and the harmonic structure units correspond to each other. The units are all module arrays, and the module arrays all include a plurality of columnar modules arranged in sequence. 3. multiple harmonic filter as claimed in claim 2, is characterized in that: the harmonic structural unit that the inner end face of described top assembly and bottom assembly is arranged is three, respectively is harmonic structural unit one, The second harmonic structure unit and the third harmonic structure unit; the first harmonic structure unit is a module array of 9 rows and 5 columns, including 45 cylindrical modules with rounded tops; the second harmonic structure unit is 9 rows and 11 columns The module array includes 99 cylindrical modules with rounded tops; the third harmonic structure unit is a module array with 7 rows and 16 columns, including 112 cylindrical modules with rounded tops.

Images