A three-pin impedance matching method and device based on fast lookup table

Abstract

The present application relates to the technical field of impedance matching of microwave sources, and specifically relates to a three-pin impedance matching method and device based on fast lookup table. The method comprises: constructing a mapping relationship table of three-pin insertion depth and impedance, and splitting and sorting to form a real impedance matching table and an imaginary impedance matching table; obtaining electrical parameters between a microwave source and a three-pin matching device or between the three-pin matching device and a load, and calculating the load impedance; finding an index position in the real impedance matching table and the imaginary impedance matching table that is conjugate matched with the load impedance, and outputting the insertion depth of the three-pin matching data entry at the index position; and when no match is found, gradually widening the index range until a matching data entry is found, and outputting the insertion depth of the three-pin matching data entry. The present application optimizes the data structure and lookup logic of the table, reduces the data amount during lookup, significantly improves the efficiency and speed of impedance matching, and guarantees the transmission of microwave signals.

Description

Technical Field

[0001] This invention relates to the field of impedance matching for microwave sources, and specifically to a three-pin impedance matching method and apparatus based on fast table lookup. Background Technology

[0002] In microwave systems, impedance matching between the load and the microwave source is a crucial prerequisite for optimal power signal transmission. Existing technologies typically establish a database of mapping relationships between the insertion depth of the three pins and the load impedance through finite element method simulation or experimental measurement. They then use six-port devices or dual directional couplers to obtain the reflection coefficient and calculate the load impedance, determine the target insertion depth of the three pins by looking up a table, and finally control the matching device to complete the impedance matching.

[0003] However, existing technologies have significant drawbacks: on the one hand, the database of the mapping relationship between the three pin depth and the load impedance contains a large number of permutation and combination data, resulting in a huge table size; on the other hand, the lookup algorithm is relatively outdated, using a polling method to traverse the entire array to find matching data, which not only has low lookup efficiency but also causes the adjustment speed of the three pin matcher to be slow, making it difficult to meet the application requirements of fast impedance matching in the industrial field and limiting the efficient operation of microwave systems in real-world scenarios.

[0004] Existing literature CN116029247A provides a path planning method for a three-pin impedance matcher, belonging to the impedance matching technology field within microwave energy applications. This method involves calculating the optimal depth of the three pins based on the reflection coefficient measured at the port when the load changes; then, based on the calculated optimal pin depth, implementing a low-reflection adjustment strategy to adjust the pin depth, avoiding large reflections during the adjustment process. However, this method does not optimize the data filtering of the three-pin impedance matching mapping table, still employing an outdated lookup algorithm with polling and traversal. This results in a large matching table data volume and low lookup efficiency, leading to slow three-pin impedance matching adjustment speed, which cannot meet the high-efficiency application requirements in industrial fields. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of large matching table data and outdated lookup algorithms in existing microwave systems, which result in low lookup efficiency and slow matching adjustment speed, and to provide a three-pin impedance matching method and device based on fast lookup.

[0006] In a first aspect, the present invention provides a three-pin impedance matching method based on fast table lookup, the method comprising the following steps:

[0007] S1. Construct a mapping table between the insertion depth of the three pins and the impedance of the three pins;

[0008] The real part and the imaginary part of the three-pin impedance in the above mapping table are sorted in the same way to form a real part impedance matching table and an imaginary part impedance matching table.

[0009] S2. Obtain the electrical parameters between the microwave source and the three-pin matching device, or between the three-pin matching device and the load, and calculate the load impedance;

[0010] S3. Find the real part index position and imaginary part index position that are conjugate matched with the above load impedance in the above real part impedance matching table and imaginary part impedance matching table respectively.

[0011] If the real part index position and the imaginary part index position point to the same data entry, output the three-pin insertion depth corresponding to that data entry.

[0012] If the real part index position and the imaginary part index position do not point to the same data entry, the preset index range of the real part index position and the imaginary part index position is gradually widened according to the gradient until the real part index position and the imaginary part index position pointing to the same data entry can be extracted from the two widened index ranges, and the three-pin insertion depth corresponding to the data entry is output.

[0013] By constructing a split and sorted real and imaginary impedance matching table, and combining a conjugate matching index lookup and a gradually widening range strategy, the lookup logic is optimized, the targeting and feasibility of matching lookup are improved, the lookup time is reduced, and the impedance matching efficiency is increased.

[0014] Preferably, when the pin spacing of the three pins is 1 / 4 waveguide wavelength, the above mapping table only retains data where the first pin insertion depth is 0 or the third pin insertion depth is 0.

[0015] When the pin spacing is 1 / 4 waveguide wavelength, specific insertion depth data is retained, redundant data is eliminated, and the amount of data in the mapping table is reduced from N³ to 2N² (where N is the number of table points for adjusting the depth of a single pin), further simplifying the table lookup process and improving the lookup speed.

[0016] Preferably, when searching for the real part index position and imaginary part index position that are conjugate matched with the load impedance in the above real part impedance matching table and imaginary part impedance matching table, the binary search method is used.

[0017] Using a binary search method to find the index position of the conjugate match reduces the number of table lookups from M (where M is the number of rows in the lookup table) to [number missing]. This significantly improves the search efficiency and shortens the response time for impedance matching.

[0018] Preferably, in S3, if there are multiple data entries pointing to the real part index position and the imaginary part index position of the same data entry, the matching errors of the multiple data entries are compared, and the insertion depth of the three pins corresponding to the data entry with the smallest matching error is taken as the output result.

[0019] When there are multiple target data entries, the optimal result is selected by comparing the matching error to ensure that the matching effect corresponding to the insertion depth of the three pins is better, thereby improving the accuracy of impedance matching.

[0020] Preferably, the matching error is calculated using the following formula:

[0021]

[0022] in, The above-mentioned matching error; The impedance of the three pins mentioned above; The above refers to the load impedance.

[0023] A clear formula for calculating the matching error provides a quantitative basis for screening multiple target data entries, making the selection of the optimal insertion depth more accurate.

[0024] Preferably, in S1, the three-pin matched circuit is considered as a two-port network. The scattering parameters corresponding to any insertion depth of the three-pin matched circuit are obtained using an analyzer, and a table relating the scattering parameters to the insertion depth is established. The three-pin impedance is calculated using the following formula:

[0025]

[0026] In the formula, The impedance of the three pins mentioned above; The characteristic impedance of the three pins; The scattering parameters of the two-port network are given. Based on the correspondence table between scattering parameters and insertion depth, the three-pin impedance corresponding to the scattering parameters is calculated, and then a mapping table between the insertion depth of the three pins and the impedance of the three pins is established.

[0027] By treating the three-pin matched network as a two-port network and calculating the three-pin impedance using scattering parameters and characteristic impedance, the established mapping table data is more accurate, providing a reliable data foundation for subsequent conjugate matching searches.

[0028] Preferably, the real impedance matching table is sorted in ascending or descending order of the real part of the three-pin impedance in a single column, and the real part index position and the imaginary part index position are both row numbers; or the real impedance matching table is sorted in ascending or descending order of the real part of the three-pin impedance in a single row, and the real part index position and the imaginary part index position are both column numbers.

[0029] Clearly define the sorting method and index position of the partial impedance matching table, standardize the table data structure, and ensure the orderliness and accuracy of the search process.

[0030] Preferably, in S2, the reflection coefficient is calculated using electrical parameters, and then the load impedance is calculated using the following formula:

[0031]

[0032] in, The load impedance; Characteristic impedance; The reflection coefficient at the load end; , , , All are scattering coefficients of a two-port network.

[0033] By calculating the load impedance using the reflection coefficient and characteristic impedance, a standardized path for obtaining load impedance is provided, ensuring the accuracy of load impedance data and providing precise input for conjugate matching.

[0034] Preferably, it further includes S4: controlling the three-pin matching device to adjust the pins to the corresponding positions according to the insertion depth of the three pins to complete impedance matching.

[0035] Adding a closed-loop step for adjusting the position of the three pins creates a complete execution flow for the impedance matching method, ensuring the practicality of the method from data lookup to actual matching.

[0036] In a second aspect, the present invention provides a three-pin impedance matching device based on fast lookup table. The device includes at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to perform the aforementioned three-pin impedance matching method based on fast lookup table.

[0037] A hardware device adapted to the above matching method is provided, which supports the automated execution of the method through the coordinated work of the processor and memory, and realizes fast and accurate three-pin impedance matching.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] This invention provides a three-pin impedance matching method and apparatus based on fast table lookup. The method optimizes the data structure of the tables by constructing a mapping table between the insertion depth of the three pins and the impedance, and then splitting and sorting it into a real part impedance matching table and an imaginary part impedance matching table. This improves the targeting of the index lookup. By obtaining electrical parameters to calculate the load impedance, an accurate basis is provided for conjugate matching lookup. A strategy of first performing a precise lookup and then gradually widening the index range ensures lookup efficiency. Through these methods, invalid traversals in the table lookup process are directly reduced, improving the accuracy and speed of the matching lookup, thereby significantly improving the efficiency of three-pin impedance matching and ensuring efficient transmission of power signals in microwave systems. Attached Figure Description

[0040] Figure 1 This is a flowchart of the table lookup method in Example 1.

[0041] Figure 2 This is a simplified schematic diagram of a system in Example 3 where the three-pin matcher is considered as a two-port network.

[0042] Figure 3 is a schematic diagram of the Smith chart adjustment range of different pin combinations of the waveguide cascade pin tuner in Example 4.

[0043] Figure 3(a) is a schematic diagram of the Smith chart adjustment range of a single pin in the waveguide cascade pin tuner in Example 4.

[0044] Figure 3(b) is a schematic diagram of the Smith chart adjustment range of the waveguide cascade pin tuner pin 1 and 2 cascaded combination in Example 4.

[0045] Figure 3(c) is a schematic diagram of the Smith chart adjustment range of the waveguide cascade pin tuner pin 1 and 3 cascaded combination in Example 4.

[0046] Figure 3(d) is a schematic diagram of the Smith chart adjustment range of the waveguide cascade pin tuner pins 2 and 3 cascaded in Example 4. Detailed Implementation

[0047] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0048] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0049] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0050] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0051] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0052] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0053] Example 1

[0054] To clearly illustrate the method described in this invention, this embodiment will provide a detailed explanation of the four core steps: table construction, load impedance calculation, target insertion depth lookup, and matching completion.

[0055] 1. Construct a mapping table and an impedance matching table for the real and imaginary parts:

[0056] The impedance characteristics of a three-pin matched circuit are directly related to its insertion depth. To establish a precise correlation between the two, the three-pin matched circuit is first treated as a two-port network. A professional analyzer is used to collect parameters for different insertion depth combinations of the three pins, obtaining the scattering parameters (S-parameters) corresponding to each insertion depth combination, and establishing a table showing the correspondence between scattering parameters and insertion depth. Scattering parameters accurately reflect the port characteristics of a two-port network and are a key basis for calculating the impedance of the three-pin matched circuit.

[0057] Based on the above correspondence table, combined with the preset characteristic impedance of the three pins... The three-pin impedance corresponding to each scattering parameter is calculated using the following three-pin impedance calculation formula. :

[0058]

[0059] In the formula, For three-pin impedance; The characteristic impedance of the three pins; This is the scattering parameter of the two-port network, which is directly related to the reflection characteristics of the two-port network. Its measurement accuracy directly affects the accuracy of the three-pin impedance calculation.

[0060] Based on the calculated three-pin impedance and corresponding insertion depth, a mapping table between the three-pin insertion depth and the three-pin impedance is established. This table serves as the basic data carrier for subsequent table lookup and matching.

[0061] To improve the targeting and efficiency of subsequent lookup processes, the three-pin impedances in the aforementioned mapping table are separated into real and imaginary parts. The same sorting method is used to sort the real and imaginary parts of the impedances separately, forming a real impedance matching table and an imaginary impedance matching table. The sorting method can be flexibly chosen: either in a single column, they can be sorted in ascending or descending order of the real and imaginary parts of the impedance, in which case the real and imaginary part index positions correspond to the table row numbers; or in a single row, they can be sorted in ascending or descending order of the real and imaginary parts of the impedance, in which case the real and imaginary part index positions correspond to the table column numbers. Both sorting methods can meet the requirement of orderliness for subsequent lookups.

[0062] 2. Calculate the load impedance:

[0063] Load impedance is the target reference parameter for impedance matching, and its calculation accuracy directly determines the quality of the matching effect. Electrical parameters between the microwave source and the three-pin matching device, or between the three-pin matching device and the load, are collected by sensors. These electrical parameters include key parameters that reflect the load impedance characteristics, such as incident voltage and reflected voltage.

[0064] Based on the collected electrical parameters, the reflection coefficient at the load end is calculated using relevant algorithms. The reflection coefficient can directly reflect the degree of impedance mismatch between the load and the transmission line. Combined with the characteristic impedance... The load impedance is calculated using the following formula. :

[0065]

[0066] in, The load impedance; Characteristic impedance; The reflection coefficient at the load end; , , , All are scattering coefficients of a two-port network.

[0067] This formula can quickly and accurately derive the load impedance based on the reflection coefficient and characteristic impedance, providing accurate target parameters for subsequent conjugate matching.

[0068] 3. Determine the target insertion depth:

[0069] Finding the target insertion depth is the core step in achieving fast impedance matching. This method uses a bisection approach to search for the real and imaginary index positions that are conjugate matches to the load impedance in both the real and imaginary impedance matching tables. The bisection approach leverages the sorting properties of the tables, repeatedly dividing the search range in half to quickly locate the target index position. Compared to the traditional polling traversal method, this effectively reduces unnecessary search steps and significantly improves search efficiency and accuracy.

[0070] By combining sorting with binary search, the number of table lookups is reduced from M times in the traditional round-robin traversal to a much faster number. This significantly reduces lookup time and effectively shortens the response time of impedance matching. M represents the total number of rows in the real or imaginary impedance matching table. Since both the real and imaginary impedance matching tables are formed by splitting and sorting the same mapping table, they contain the same number of data entries. Therefore, M is used to represent the number of rows in the lookup table.

[0071] To more clearly illustrate the optimization effect of binary search on the number of searches, the following example is provided in a real-world table creation scenario:

[0072] Assume that the number of rows in the real part impedance matching table or the imaginary part impedance matching table is M=1000.

[0073] The traditional polling traversal algorithm searches by comparing each row in the table starting from the first row until it finds the index position that matches the load impedance. In the worst case, it requires traversing all data entries, meaning the number of searches is M=1000. The binary search method, however, leverages the sorting properties of the table to narrow down the target interval by continuously dividing the search range in half. The specific search process is as follows:

[0074] First search: Take the impedance value corresponding to the middle row (row 500) of the table and compare it with the target conjugate impedance to determine whether the target impedance is located in the first half (rows 1 to 499) or the second half (rows 501 to 1000). At this time, the search range is reduced from row 1000 to row 500, and the search count is 1.

[0075] Second search: Take the middle row of the narrowed interval (row 250 or row 750) and compare it again to further narrow the search range to 250 rows, and search twice;

[0076] Repeat the above steps, halving the search range with each search, until the target index position is located.

[0077] For a lookup table with M=1000 rows, the maximum number of searches using binary search is: ( (≈10 times), meaning the target index can be found with a maximum of only 10 comparisons, while traditional round-robin traversal requires up to 1000 comparisons in the worst case. By using sorting combined with binary search, the number of table lookups is reduced from M times in traditional round-robin traversal to as little as 10 times. This significantly reduces the search time and effectively shortens the response time of impedance matching.

[0078] The binary search method is used to find the real part index position Row1 and the imaginary part index position Row2 that are conjugate matches with the load impedance in the real part impedance matching table and the imaginary part impedance matching table, respectively. In this embodiment, Row1 can also be said to be the row number or column number of the real part impedance matching table that is conjugate matches with the load impedance in the real part impedance matching table, and Row2 is the row number or column number of the imaginary part impedance matching table that is conjugate matches with the load impedance in the imaginary part impedance matching table.

[0079] Next, perform a table lookup and determination according to the following logic:

[0080] (1) If Row1 and Row2 are completely identical, they are determined to point to the same data entry. That is, the same row number corresponds to the same group of "three-pin insertion depth combination" in the real part impedance matching table and the imaginary part impedance matching table. The insertion depth of the three pins in this group is directly output.

[0081] (2) If Row1 and Row2 are inconsistent, it is determined that they do not point to the same data entry. The row number range is widened according to the following gradient. The core goal is to find the data entry that "exists in both the widened row number range of the real part and the widened row number range of the imaginary part, and corresponds to the same set of three-pin insertion depth combinations". The steps are as follows:

[0082] First, the index range is widened by gradient with the 10 rows before and after each of Row1 and Row2. That is, the row number range after gradient widening at the real part index position is [Row1-10,Row1+10], and the row number range after gradient widening at the imaginary part index position is [Row2-10,Row2+10].

[0083] Extract all row numbers within the real part widening range and all row numbers within the imaginary part widening range. If there is a unique row number that is equal, output the insertion depth of the corresponding unique row number; if there are multiple row numbers that are equal, determine the matching error; if there are no row numbers that are equal, continue to widen.

[0084] If multiple identical insertion depth combinations are found in two sets of combinations, the matching error of each data entry corresponding to the multiple identical insertion depth combinations is calculated using the following formula:

[0085]

[0086] in, The above-mentioned matching error; The impedance of the three pins mentioned above; The above refers to the load impedance.

[0087] This formula can quantify the degree of matching between the three-pin impedance and the load impedance. The smaller the error value, the better the matching effect. Therefore, the insertion depth of the three-pin corresponding to the data item with the smallest matching error is selected as the output result.

[0088] 4. Complete impedance matching:

[0089] After determining the target insertion depth of the three pins, the actual impedance matching operation needs to be performed by a hardware actuator. Based on the determined insertion depth, a control command is sent to the drive mechanism of the three-pin matcher. Upon receiving the command, the drive mechanism precisely adjusts each of the three pins to its corresponding insertion depth, ultimately achieving impedance conjugate matching between the load and the microwave source. This ensures that the microwave signal can be transmitted in optimal condition, fully utilizing the performance of the microwave system. The above method flow is as follows: Figure 1 As shown.

[0090] Example 2

[0091] To enable the above-mentioned three-pin impedance matching method to be executed efficiently and automatically, this embodiment provides a hardware device adapted to the method. Through the collaborative work of the processor and memory, it provides stable hardware support for the implementation of the method, ensuring the accuracy and efficiency of the impedance matching process.

[0092] This fast lookup-based three-pin impedance matching device includes at least one processor and a memory communicatively connected to the processor. The functions and coordination logic of each component are as follows:

[0093] As a non-transitory computer-readable storage medium, memory plays a core role in data storage and program delivery. Internally, it stores instructions executable by the processor. These instructions contain complete program code implementing the three-pin impedance matching method described above, guiding the processor to perform table lookup, calculation, and control operations step by step. Simultaneously, memory also stores fundamental data such as the constructed real impedance matching table, imaginary impedance matching table, and mapping relationship table, providing data support for the lookup process and ensuring the timeliness and accuracy of data retrieval.

[0094] The processor is the core control unit of the device, responsible for executing the instructions stored in the memory. Its specific execution process includes: actively retrieving matching table data stored in the memory; receiving electrical parameter signals transmitted by the sensors; performing core operations such as load impedance calculation and target insertion depth search according to the logic described in this invention; and then outputting precise control signals to the drive mechanism of the three-pin matcher to drive the pin position adjustment to complete impedance matching.

[0095] The device can also be flexibly configured with auxiliary components such as sensor modules for collecting electrical parameters and execution modules for driving pin adjustments, according to actual application needs. Each module works together to support the automated and precise execution of the impedance matching method, meeting the application needs in different scenarios.

[0096] Example 3

[0097] The two-port network model of the three-pin matched pin is the theoretical basis for constructing the insertion depth and impedance mapping table. The rationality and rigor of its derivation process directly affect the accuracy of the mapping table data, and thus the effect of the entire impedance matching method. Therefore, this embodiment elaborates on the establishment of the model and the derivation logic of the core impedance formula.

[0098] Two-port network definition

[0099] To accurately describe the electrical characteristics of the three-pin connector, it is equivalent to a two-port network, which includes a first port (Port1) and a second port (Port2). The first port is used to connect a microwave source, and the second port is used to connect a load. A simplified system diagram treating the three-pin connector as a two-port network is shown below. Figure 2 As shown.

[0100] definition , These are the incident voltage and reflected voltage at the first port, respectively; , These are the incident voltage and reflected voltage at the second port, respectively; , , , These are the port scattering parameters of this two-port network: When a matched load is connected to the second port (port2) of the two-port network, the reflection coefficient of the first port (port1) reflects the reflection characteristics of the first port. When a matched load is connected to the first port of the two-port network, the transmission coefficient from the second port to the first port reflects the transmission characteristics of the signal from the second port to the first port. When a matched load is connected to the second port of the two-port network, the transmission coefficient from the first port to the second port reflects the transmission characteristics of the signal from the first port to the second port. When a matched load is connected to the first port of the two-port network, the reflection coefficient of the second port reflects the reflection characteristics of the second port.

[0101] The derivation of the core formula follows the basic principles of microwave technology, gradually establishing the relationship between scattering parameters, reflection coefficient, and impedance:

[0102] (1) Definition of reflection coefficient at the first port:

[0103]

[0104] In the formula The reflection coefficient of the first port is defined as the reflection coefficient, which is directly related to the incident voltage and the reflected voltage and forms the basis for subsequent derivations.

[0105] (2) Equations for scattering parameters of a two-port network:

[0106]

[0107] This equation is the core equation describing the characteristics of a two-port network, and it clarifies the linear relationship between the incident voltage, the reflected voltage, and the scattering parameters.

[0108] (3) By combining the above two equations and eliminating irrelevant variables, the reflection coefficient of the second port can be derived. :

[0109]

[0110] This formula establishes the relationship between the reflection coefficient of the first port and the reflection coefficient of the second port.

[0111] (4) Relationship between load impedance and reflection coefficient:

[0112]

[0113] in, The load impedance; This is the characteristic impedance.

[0114] (5) Combining steps (3) and (4), the normalized load impedance is derived through algebraic transformation. :

[0115]

[0116] (6) Formula for calculating the normalized impedance of a three-pin pin:

[0117]

[0118] middle, The impedance of the three pins mentioned above.

[0119] The core condition for achieving load impedance matching is: the normalized load impedance ( ) and the normalized impedance of the three pins ( Conjugate matching. Based on the derived formulas and matching conditions, the impedance of the three pins can be accurately calculated using scattering parameters, providing a theoretical basis for the construction of the mapping table and ensuring the reliability and accuracy of the mapping table data.

[0120] Example 4

[0121] In practical applications, the pin spacing of the three pins has a significant impact on the impedance matching range. When the pin spacing meets specific conditions, the mapping table can be further optimized to reduce the amount of data, decrease the complexity of table lookup, and improve the lookup speed. This embodiment focuses on a typical scenario where the pin spacing is 1 / 4 of the waveguide wavelength, and details the optimization strategy and principle of the mapping table.

[0122] 1. Spacing Characteristics Analysis:

[0123] When the spacing between adjacent pins of the three pins is set to 1 / 4 of the waveguide wavelength, the adjustment range of the cascaded pin combinations is analyzed using the Smith chart. The results show that the adjustment ranges corresponding to the cascaded combinations of the first and second pins, and the cascaded combinations of the second and third pins, are oddly symmetrical about the origin of the Smith chart. This symmetry allows the adjustment ranges of the two cascaded combinations to complement each other, and when superimposed, they can completely cover the entire Smith chart, as shown in Figure 3. Figure 3(a) is the Smith chart of a single pin, Figure 3(b) is the Smith chart of the cascaded combination of pins 1 and 2, Figure 3(c) is the Smith chart of the cascaded combination of pins 1 and 3, and Figure 3(d) is the Smith chart of the cascaded combination of pins 2 and 3.

[0124] In other words, impedance conjugate matching across the entire range can be achieved simply by adjusting the combination of the insertion depths of the first and second pins, or the combination of the insertion depths of the second and third pins, without the need to adjust the insertion depths of all three pins simultaneously.

[0125] 2. Optimization of mapping relationship table:

[0126] Based on the above characteristics, to achieve a lightweight mapping table and improve lookup efficiency, data filtering optimization is performed on the mapping table. The specific optimization strategy is to remove redundant data where neither the first nor the third pin insertion depth is zero, retaining only data entries where either the first or third pin insertion depth is zero. This optimization method can minimize invalid data in the table and improve lookup efficiency without affecting the integrity of the allocation range.

[0127] 3. Optimization effect

[0128] Assuming the number of table points corresponding to the adjustment depth of a single pin is N, the data volume of the mapping table before optimization is N³, which comes from all permutations and combinations of the insertion depths of the three pins. After optimization, the data volume of the mapping table is reduced to 2N², that is, N² combinations when the first pin insertion depth is 0 plus N² combinations when the third pin insertion depth is 0. This significant reduction in data volume not only reduces memory usage but also further simplifies the table lookup process, shortens lookup time, and further improves the response speed of impedance matching.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-pin impedance matching method based on fast table lookup, characterized in that, The method includes the following steps: S1. Construct a mapping table between the insertion depth of the three pins and the impedance of the three pins; The real part and the imaginary part of the three-pin impedance in the mapping table are sorted in the same way to form a real part impedance matching table and an imaginary part impedance matching table. S2. Obtain the electrical parameters between the microwave source and the three-pin matching device, or between the three-pin matching device and the load, and calculate the load impedance; S3. Find the real part index position and imaginary part index position that are conjugate matched with the load impedance in the real part impedance matching table and the imaginary part impedance matching table, respectively. If the real part index position and the imaginary part index position point to the same data entry, output the three-pin insertion depth corresponding to that data entry; If the real index position and the imaginary index position do not point to the same data entry, the preset index range is gradually widened for the real index position and the imaginary index position according to the gradient until the real index position and the imaginary index position pointing to the same data entry can be extracted from the two widened index ranges, and the three-pin insertion depth corresponding to the data entry is output.

2. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, When the pin spacing of the three pins is 1 / 4 waveguide wavelength, the mapping table only retains data where the first pin insertion depth is 0 or the third pin insertion depth is 0.

3. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, When searching for the real part index position and imaginary part index position that are conjugate to the load impedance in the real part impedance matching table and the imaginary part impedance matching table, the binary search method is used.

4. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, In S3, if there are multiple data entries pointing to the real part index position and the imaginary part index position of the same data entry, the matching error of the multiple data entries is compared, and the insertion depth of the three pins corresponding to the data entry with the smallest matching error is taken as the output result.

5. The three-pin impedance matching method based on fast table lookup according to claim 4, characterized in that, The matching error is calculated using the following formula: in, The matching error; The impedance of the three pins; The load impedance is denoted as .

6. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, In S1, the three-pin matcher is regarded as a two-port network. The scattering parameters corresponding to any insertion depth of the three-pin matcher are obtained by the analyzer, and a correspondence table between the scattering parameters and the insertion depth is established. The impedance of the three pins is calculated using the following formula: In the formula, The impedance of the three pins; The characteristic impedance of the three pins; These are the scattering parameters of a two-port network; Based on the correspondence table between scattering parameters and insertion depth, after calculating the three-pin impedance corresponding to the scattering parameters, a mapping table between the insertion depth of the three pins and the impedance of the three pins is established.

7. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, The real impedance matching table is sorted in ascending or descending order of the real part of the three-pin impedance in a single column, with the real part index position and the imaginary part index position both being row numbers; or the real impedance matching table is sorted in ascending or descending order of the real part of the three-pin impedance in a single row, with the real part index position and the imaginary part index position both being column numbers.

8. The three-pin impedance matching method based on fast table lookup according to claim 6, characterized in that, In S2, the reflection coefficient is calculated using electrical parameters, and then the load impedance is calculated using the following formula: in, The load impedance; Characteristic impedance; The reflection coefficient at the load end; , , , All are scattering coefficients of a two-port network.

9. The three-pin impedance matching method based on fast table lookup according to claim 1, characterized in that, It also includes S4: controlling the three-pin matching device to adjust the pins to the corresponding positions according to the insertion depth of the three pins to complete impedance matching.

10. A three-pin impedance matching device based on fast table lookup, characterized in that, The method includes at least one processor and a memory communicatively connected to the at least one processor; the memory stores instructions executable by the at least one processor, which, when executed by the at least one processor, enable the at least one processor to perform a three-pin impedance matching method based on fast lookup table as described in any one of claims 1 to 9.

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