Asymmetric superconducting resonator, coupling filter and microwave multiplexing filter

Abstract

The invention discloses an asymmetric superconducting resonator, a coupling filter and a microwave multiplexing filter, and relates to the technical field of microwave communication. The first part microstrip line, the third part microstrip line, the fifth part microstrip line and the seventh part microstrip line of the asymmetric superconducting resonator are parallel to one another, the length of the first part microstrip line is the same as that of the third part microstrip line, and the length of the fifth part microstrip line is the same as that of the seventh part microstrip line; the length of the first part microstrip line is greater than that of the fifth part microstrip line; the second, fourth and sixth microstrip lines are parallel to each other; the distance between the first part microstrip line and the seventh part microstrip line, the distance between the seventh part microstrip line and the fifth part microstrip line, the distance between the third part microstrip line and the fifth part microstrip line, and the distance between the second part microstrip line and the sixth part microstrip line are the same. The invention aims to reduce related interference between circuits and has universality.

Description

Technical Field

[0001] The present application relates to the field of microwave communication technology, and in particular to an asymmetric superconducting resonator, a coupling filter and a microwave multiplexer filter. Background Art

[0002] With the rapid development of wireless communication technology, more and more communication frequency bands are being developed and utilized, and the electromagnetic environment in space has become very complex. The performance requirements of microwave filters for high-performance microwave receiver front ends are also getting higher and higher. The ideal microwave filter has a rectangular filtering characteristic, which can filter out the signals of the required frequency band and completely filter out the signals of the remaining frequency bands. Due to factors such as the microwave loss of metal materials, the filtering performance of actual microwave filters is far behind that of ideal filters. Compared with conventional metals, the surface resistance of high-temperature superconducting materials in the microwave frequency band is two to three orders of magnitude smaller, which is very small. Resonators and filters made of high-temperature superconducting materials have a series of advantages such as low loss and high frequency selectivity, which can greatly improve the sensitivity of microwave receivers and other performance.

[0003] The microwave receiver of the wireless communication system usually needs to process signals of different frequency bands and receive the signals in different frequency bands. The structure size of the microwave receiver is limited, and it is impossible to set up independent microwave receiving components for each frequency band. The solution is to install a microwave multiplexer filter in the same microwave receiving link, process the signal at the common input end, and output it from different microwave ports to realize the reception and processing of multi-band microwave signals. The key performance indicators of the microwave multiplexer filter include parameters such as the operating frequency band, input matching circuit, and isolation between different frequency bands.

[0004] The key to the design of microwave multiplexer filters is to reduce the crosstalk between channel circuits in different frequency bands in order to obtain good input common port matching and isolation between channels. The main design methods of microwave multiplexer filters include hybrid bridge coupling method, circulator coupling method, directional filter method and multi-branch coupling method. Among them, the design difficulty of hybrid bridge coupling method and circulator coupling method is relatively small, but the cost is large volume and poor insertion loss performance. Therefore, the research on multiplexer design is mainly focused on directional filtering method and multi-branch coupling method. The focus of multi-branch coupling method in designing multiplexers is the impedance matching problem between channels. As the number of channels increases, the impedance matching problem will become very complicated. Accurate impedance matching methods can effectively improve the design efficiency of multiplexers. Commonly used design methods include network comprehensive design method, T-joint method, shared coupling feeder method, shared first-section resonator method, etc.

[0005] The network synthesis design method establishes a low-pass prototype circuit of the multiplexer, and obtains the characteristic polynomial of the multiplexer according to the pole and zero positions of each channel of the multiplexer. The characteristic polynomial of each channel filter and the connection parameters of the filter connection are optimized with the characteristic polynomial of the multiplexer as the optimization target. Macchiarella G, Tamiazzo S. Synthesis of star-unction multiplexers [J]. IEEE Transactions on Microwave Theory and Techniques, 2010, 58 (12): 3732-3741. A waveguide triplexer was designed and implemented using the network synthesis design method.

[0006] The T-connector method directly connects the designed single-channel filters through a T-connector, and improves the impedance matching between channels by optimizing the T-connector structure and the filter parameters of each channel, thereby obtaining a good common port reflection. Since the single-channel filter only considers the matching of its own passband when it is designed, the mutual influence when it is directly connected using a T-connector cannot be predicted, and it is almost impossible to form a good match without special design. The key to designing a multiplexer using the T-connector method is to realize a T-connector structure with good matching and little influence on the in-band response of the original channel filter. Hong S, Chang KA 10-35GHzsix-channel microstrip multiplexer for wide-band communication systems[J].IEEE Transactions on Microwave Theory and Techniques, 2006, 54(4):1370-1378. A high-frequency six-channel duplexer for broadband communication was designed.

[0007] The shared coupling feeder method uses the input and output main coupling feeders as the basic structure. The filter circuits of different frequency bands are arranged on the left and right sides of the main coupling feeder. The isolation between the filter circuits of different frequency bands is achieved by adjusting the position and shape of the first section resonator. Tu W, Wu C. Design of microstrip low-pass-bandpass multiplexers using distributed coupling technique [J]. IEEE Transactions on Components, Packaging and Manufacturing Technology, 2016, 6 (11): 1648-1655. A quintuplexer was designed using the shared coupling feeder method.

[0008] The shared first-section resonator method directly cascades a first-stage resonator at the end of the input feed line, and the first-stage resonator has dual-mode or multi-mode resonance characteristics. Filter circuits of different frequency bands are cascaded at specific positions of the first-stage resonator. Chen C, Huang T, Chou C, et al. Microstrip diplexers design with common resonator sections for compact size, but high isolation [J]. IEEE Transactions on Microwave Theory and Techniques, 2006, 54 (5): 1945-1952. A duplexer was designed using the shared first-section resonator method.

[0009] In the above microwave multiplexer design methods, it is difficult to simultaneously obtain good performance for parameters such as isolation between different frequency bands, compact structure of the device, and input coupling matching structure. The use of T-joints and optimized T-joint structures are widely used methods, but they are very difficult to design and the circuit is difficult to manufacture, and there is a lack of universal design methods. Summary of the invention

[0010] The purpose of the present application is to provide an asymmetric superconducting resonator, a coupled filter and a microwave multiplexer filter, which can reduce interference and have universality.

[0011] To achieve the above objectives, this application provides the following solutions:

[0012] In a first aspect, the present application provides an asymmetric superconducting resonator, comprising:

[0013] a first portion of microstrip line, a second portion of microstrip line, a third portion of microstrip line, a fourth portion of microstrip line, a fifth portion of microstrip line, a sixth portion of microstrip line and a seventh portion of microstrip line;

[0014] The first portion of the microstrip line, the third portion of the microstrip line, the fifth portion of the microstrip line and the seventh portion of the microstrip line are parallel to each other, and the length of the first portion of the microstrip line is the same as the length of the third portion of the microstrip line, and the length of the fifth portion of the microstrip line is the same as the length of the seventh portion of the microstrip line; the length of the first portion of the microstrip line is greater than the length of the fifth portion of the microstrip line;

[0015] The second portion of the microstrip line, the fourth portion of the microstrip line and the sixth portion of the microstrip line are parallel to each other;

[0016] The first portion of the microstrip line is perpendicular to the second portion of the microstrip line, and one end of the first portion of the microstrip line is connected to one end of the second portion of the microstrip line; the other end of the second portion of the microstrip line is connected to one end of the third portion of the microstrip line, and the third portion of the microstrip line is perpendicular to the second portion of the microstrip line;

[0017] The other end of the third microstrip line is connected to one end of the fourth microstrip line, and the third microstrip line is perpendicular to the fourth microstrip line; the other end of the fourth microstrip line is connected to one end of the fifth microstrip line, and the fourth microstrip line is perpendicular to the fifth microstrip line; the other end of the fifth microstrip line is connected to one end of the sixth microstrip line, and the fifth microstrip line is perpendicular to the sixth microstrip line; the other end of the sixth microstrip line is connected to one end of the seventh microstrip line; the sixth microstrip line is perpendicular to the seventh microstrip line;

[0018] The spacing between the first portion of the microstrip line and the seventh portion of the microstrip line, the spacing between the seventh portion of the microstrip line and the fifth portion of the microstrip line, the spacing between the third portion of the microstrip line and the fifth portion of the microstrip line, and the spacing between the second portion of the microstrip line and the sixth portion of the microstrip line are all the same.

[0019] Optionally, the length of the first portion of the microstrip line is 1.56 mm.

[0020] Optionally, the length of the fifth portion of the microstrip line is 0.96 mm.

[0021] Optionally, a distance between the first portion of microstrip line and the seventh portion of microstrip line is 0.3 mm.

[0022] Optionally, the line widths corresponding to the first portion of the microstrip line, the second portion of the microstrip line, the third portion of the microstrip line, the fourth portion of the microstrip line, the fifth portion of the microstrip line, the sixth portion of the microstrip line and the seventh portion of the microstrip line are all the same; the line width is 0.3 mm.

[0023] In a second aspect, the present application provides an asymmetric superconducting resonator coupling filter, the asymmetric superconducting resonator coupling filter comprising: an input feeder, an output feeder and a coupling structure; the coupling structure is obtained by electric field coupling or magnetic field coupling of the asymmetric superconducting resonator;

[0024] The input feeder is connected to one end of the coupling structure; the output feeder is connected to the other end of the coupling structure;

[0025] The input feed line consists of a straight structure and a bent structure; the straight structure is perpendicular to and connected to the bent structure; the bent structure is used to adjust the coupling degree.

[0026] Optionally, the coupling structure comprises at least one group of resonators; each group of resonators comprises two asymmetric superconducting resonators;

[0027] The two asymmetric superconducting resonators are symmetrically arranged at a set interval.

[0028] Optionally, if the capacitance regions of the two asymmetric superconducting resonators are symmetrically arranged according to the set interval, electric field coupling is performed; the capacitance region is an opening region where the first part of the microstrip line and the seventh part of the microstrip line are located;

[0029] If the inductance regions of the two asymmetric superconducting resonators are symmetrically arranged according to the set interval, magnetic field coupling is performed; the inductance region is a folded region after removing the capacitance region.

[0030] In a third aspect, the present application provides a microwave multiplex filter, the microwave multiplex filter comprising a plurality of asymmetric superconducting resonator coupled filters;

[0031] A plurality of the asymmetric superconducting resonator coupling resonators are connected via microstrip lines.

[0032] Optionally, a multi-branch coupling method is used to iteratively optimize the length of the microstrip line to achieve impedance matching, and filtering performance simulation is performed based on simulation software to achieve passband matching.

[0033] According to the specific embodiments provided in this application, this application has the following technical effects:

[0034] The present application provides an asymmetric superconducting resonator, a coupling filter and a microwave multiplexer filter, wherein the first, third, fifth and seventh microstrip lines of the asymmetric superconducting resonator are parallel to each other, and the length of the first microstrip line is the same as the length of the third microstrip line, and the length of the fifth microstrip line is the same as the length of the seventh microstrip line; the length of the first microstrip line is greater than the length of the fifth microstrip line; the second, fourth and sixth microstrip lines are parallel to each other; the spacing between the first and seventh microstrip lines, the spacing between the seventh and fifth microstrip lines, the spacing between the third and fifth microstrip lines, and the spacing between the second and sixth microstrip lines are all the same. Based on this design structure, the defects of the existing planar microstrip structure microwave filter technology are overcome, and the problems of complex design of the T-joint matching circuit structure microwave multiplexer and large related interference between filter circuits of different frequency bands are solved, so as to achieve the purpose of reducing interference, and the design structure is simple and universal. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 Schematic diagram of the structure of an asymmetric superconducting resonator;

[0037] Figure 2 Schematic diagram of the dimensions of an asymmetric superconducting resonator;

[0038] Figure 3 is a schematic diagram of the resonator coupling mode; where Figure 3 (a) is a schematic diagram of the coupling mode dominated by electric field coupling; Figure 3 (b) is a schematic diagram of the coupling mode dominated by magnetic field coupling;

[0039] Figure 4 It is a schematic diagram of the connection between the feeder and the coupling structure;

[0040] Figure 5 It is a schematic diagram of impedance matching between the common port of the microwave multiplexer and each filter circuit;

[0041] Figure 6 A schematic diagram of the electrical length distribution of the microstrip line between the multiplexer input port and the filter circuits of each frequency band;

[0042] Figure 7 This is a schematic diagram for optimizing the electrical length of the branch lines of the first resonator in each frequency band of the multiplexer;

[0043] Figure 8 This is a circuit diagram of a superconducting microwave multiplexer with a multi-branch line coupling structure;

[0044] Fig. 9 Schematic diagram of the frequency response design results of a multi-branch line coupling structure superconducting microwave multiplexer.

[0045] Figure numerals: first portion of microstrip line-1, second portion of microstrip line-2, third portion of microstrip line-3, fourth portion of microstrip line-4, fifth portion of microstrip line-5, sixth portion of microstrip line-6, seventh portion of microstrip line-7. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0047] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0048] The present application relates to a microwave multiplexer filter which operates in a high frequency band and is designed using a multi-branch coupling method and has a planar microstrip structure made of high-temperature superconducting materials.

[0049] The purpose is to overcome the defects of existing planar microstrip structure microwave filter technology, solve the problems of complex design of microwave multiplexer with T-joint matching circuit structure, large correlated interference between filter circuits in different frequency bands, and propose a superconducting microstrip microwave multiplexer filter based on multi-branch coupling matching circuit design.

[0050] Example 1

[0051] The present application embodiment provides an asymmetric superconducting resonator. Figure 1 As shown, the asymmetric superconducting resonator includes: a first portion of microstrip line 1, a second portion of microstrip line 2, a third portion of microstrip line 3, a fourth portion of microstrip line 4, a fifth portion of microstrip line 5, a sixth portion of microstrip line 6 and a seventh portion of microstrip line 7.

[0052] The first portion microstrip line 1, the third portion microstrip line 3, the fifth portion microstrip line 5 and the seventh portion microstrip line 7 are parallel to each other, and the length of the first portion microstrip line 1 is the same as the length of the third portion microstrip line 3, and the length of the fifth portion microstrip line 5 is the same as the length of the seventh portion microstrip line 7; the length of the first portion microstrip line 1 is greater than the length of the fifth portion microstrip line 5.

[0053] The second portion of the microstrip line 2 , the fourth portion of the microstrip line 4 , and the sixth portion of the microstrip line 6 are parallel to each other.

[0054] The first portion microstrip line 1 is perpendicular to the second portion microstrip line 2, and one end of the first portion microstrip line 1 is connected to one end of the second portion microstrip line 2; the other end of the second portion microstrip line 2 is connected to one end of the third portion microstrip line 3, and the third portion microstrip line 3 is perpendicular to the second portion microstrip line 2.

[0055] The other end of the third microstrip line 3 is connected to one end of the fourth microstrip line 4, and the third microstrip line 3 is perpendicular to the fourth microstrip line 4; the other end of the fourth microstrip line 4 is connected to one end of the fifth microstrip line 5, and the fourth microstrip line 4 is perpendicular to the fifth microstrip line 5; the other end of the fifth microstrip line 5 is connected to one end of the sixth microstrip line 6, and the fifth microstrip line 5 is perpendicular to the sixth microstrip line 6. The other end of the sixth microstrip line 6 is connected to one end of the seventh microstrip line 7; the sixth microstrip line 6 is perpendicular to the seventh microstrip line 7.

[0056] The spacing between the first microstrip line 1 and the seventh microstrip line 7, the spacing between the seventh microstrip line 7 and the fifth microstrip line 5, the spacing between the third microstrip line 3 and the fifth microstrip line 5, and the spacing between the second microstrip line 2 and the sixth microstrip line 6 are all the same.

[0057] The length of the first microstrip line 1 is 1.56 mm, the length of the fifth microstrip line 5 is 0.96 mm, and the spacing between the first microstrip line 1 and the seventh microstrip line 7 is 0.3 mm.

[0058] The line widths corresponding to the first microstrip line 1, the second microstrip line 2, the third microstrip line 3, the fourth microstrip line 4, the fifth microstrip line 5, the sixth microstrip line 6 and the seventh microstrip line 7 are all the same; the line width is 0.3 mm.

[0059] The corresponding dimensions of each part of the asymmetric superconducting resonator are shown in Figure 2 .

[0060] The height of the entire resonator is 1.56mm and the length is 2.1mm. The width of the line is 0.3mm, and the interval between each line is 0.3mm when folded. Folding starts from the left side of the resonator, the vertical 0.3mm microstrip line is 1.56mm long, then fold to the right, the length is 2.1mm; then fold upward 1.56mm; then fold to the left 0.9mm; then fold downward 0.96mm, fold to the left 0.9mm, and then fold upward 0.96mm.

[0061] Example 2

[0062] An embodiment of the present application provides an asymmetric superconducting resonator coupling filter, which includes: an input feeder, an output feeder and a coupling structure; the coupling structure is obtained by performing electric field coupling or magnetic field coupling on the asymmetric superconducting resonator described in Example 1.

[0063] The input feeder is connected to one end of the coupling structure; the output feeder is connected to the other end of the coupling structure; the input feeder consists of a straight structure and a bent structure; the straight structure is perpendicular to and connected to the bent structure; the bent structure is used to adjust the coupling degree.

[0064] The coupling structure includes at least one group of resonators; each group of resonators includes two asymmetric superconducting resonators; and the two asymmetric superconducting resonators are symmetrically arranged according to a set interval.

[0065] If the capacitance regions of the two asymmetric superconducting resonators are symmetrically arranged according to a set interval, electric field coupling is performed; the capacitance region is an opening region where the first part of the microstrip line and the seventh part of the microstrip line are located.

[0066] If the inductance regions of the two asymmetric superconducting resonators are symmetrically arranged according to the set interval, magnetic field coupling is performed; the inductance region is the folded region after removing the capacitance region.

[0067] The basis of the asymmetric superconducting resonator is an open-type resonator, one part of which is a folded microstrip line close to each other, which is the inductance area; the other part is a parallel microstrip line near the opening, which is the capacitance area, and has the characteristic of electromagnetic field concentration in the resonator pattern.

[0068] like Figure 3 As shown, there are two coupling modes between adjacent resonators, namely, electric field coupling and magnetic field coupling. The distance D between resonators determines the strength of adjacent coupling.

[0069] in, Figure 3 (a) is the coupling mode dominated by electric field coupling; Figure 3 (b) is the coupling mode dominated by magnetic field coupling.

[0070] Figure 4 In the invention, the capacitive coupling is adopted between the open end of the asymmetric superconducting resonator and the input feeder and the output feeder, and the bending structure at the end of the input feeder and the output feeder is used to fine-tune the external coupling strength of the filter. The circuit corresponding to the filter is made of high-temperature superconducting materials, and the circuit substrate is made of magnesium oxide or lanthanum aluminate substrate.

[0071] The input feed line is located on one side of the first resonator, and the output feed line is located on one side of the last resonator.

[0072] Example 3

[0073] The embodiment of the present application provides a microwave multiplex filter, which includes multiple asymmetric superconducting resonator coupling filters in Embodiment 2.

[0074] A plurality of asymmetric superconducting resonator coupling resonators are connected via microstrip lines.

[0075] Specifically, the length of the microstrip line is iteratively optimized by using a multi-branch coupling method to achieve impedance matching, and filtering performance simulation is performed based on simulation software to achieve passband matching.

[0076] The impedance distribution of the microwave multiplex filter input common port and each filter circuit is as follows Figure 5 The impedance of the common input port matches the external circuit. The impedance of each frequency band filter circuit is matched with the external circuit through the electrical length design of the front-stage feeder, and the impedance in the current frequency band reaches the maximum value in other adjacent frequency bands. The electrical length distribution of the microstrip line between the multiplexer input port and the filter circuits in each frequency band is shown in Figure 6 shown.

[0077] Regarding the impedance matching process, Figure 6The three points A, B, and C in the three red circles are used as reference points for analysis and matching.

[0078] The filter operating frequencies of the four channels are f A 、f B 、f C 、f D The lengths of the microstrip lines with a characteristic impedance of 50 ohms at the input end of each channel filter are recorded as TL1, TL2, TL3, and TL4. Each transmission line TL does not change the center frequency and bandwidth characteristics of the channel filter, but only increases an electrical length to change the equivalent input impedance of each channel filter.

[0079] When impedance matching is performed, the first step is to look at the reference point C from above and see that the signal entering point C contains f C and f D The two parts of the signal, first adjust the length of TL3 for impedance matching, only let f C The band signal enters the channel C filter on the right, while the f D The frequency band signal is at high impedance and cannot enter the right channel C filter.

[0080] Then adjust TL 34 length, only let f D The signal enters the channel D filter below, and for the bottom, f C The frequency band signal is at high impedance and cannot enter the D filter of the lower channel.

[0081] The second step of impedance matching is to look at the reference point B. The signal transmitted from above and entering point B contains f B 、f C 、f D First adjust the length of TL2 for impedance matching, so that only f B The frequency band signal enters the channel B filter on the right, and the f C 、f D The frequency band signal is at high impedance and cannot enter the right channel B filter.

[0082] Then adjust TL 23 length, only let f C 、f D The signal enters the channel below and continues to reference point C.

[0083] The third step of impedance matching is to look at the reference point A from the left input feeder and enter point A. The signal contains f A 、f B 、f C 、f D All signals. First adjust the length of TL1 for impedance matching, so that only f AThe band signal enters the channel A filter on the right, and the f B 、f C 、f D The frequency band signal is at high impedance and cannot enter the right channel A filter.

[0084] Then adjust TL 12 length, only let f B 、f C 、f D The signal enters the channel below and continues to reference point B.

[0085] The present application adopts a multi-branch line microwave multiplexer design method. The electrical length of the multi-branch microstrip line between the multiplexer filter input port and each frequency band filter circuit is calculated step by step and optimized iteratively.

[0086] The impedance matching methods of the three reference points A, B, and C mentioned above will affect each other during the matching process. After a process optimizes the electrical length of each part of the transmission line, the impedance matching cannot reach the ideal situation. Then, the electrical length of each part of the transmission line is iteratively optimized according to the above process. Since the optimization process of each section of the microstrip line is carried out step by step, the impedance matching situation will gradually approach the ideal situation. The design drawing obtained by the final iterative optimization is then simulated by the professional simulation software Sonnet for filtering performance, and further fine-tuned to achieve the required matching of different passbands.

[0087] The impedance relationship between each frequency band filter circuit and the outside is mainly affected by the first section resonator. The multi-branch microstrip line design first introduces the first section resonator of each frequency band filter circuit. The first frequency band filter circuit is designed according to the length of the microstrip line of the single-channel filter; the second frequency band filter circuit selects a matching point to access the microstrip line, and optimizes the electrical length of the microstrip line at this level to obtain a suitable out-of-band impedance; the third frequency band filter circuit selects a matching point to access the second frequency band microstrip line, and optimizes the electrical length of the microstrip line at this level to obtain a suitable out-of-band impedance; iteratively optimizes the electrical length of the microstrip line in the first and second frequency bands, and then introduces the fourth frequency band filter circuit. Figure 7 shown.

[0088] The multiplexer, also known as a multiplex filter, is installed in a metal packaging box after manufacture. A microwave coaxial connector is used to connect the input port and output ports of the multiplexer circuit. The metal packaging box is.

[0089] This application can be used for the design and preparation of devices with multi-band branch output functions such as microwave duplexers, triplexers, and quadplexers, and has the advantages of high design efficiency, stable design results, and easy design expansion. Using the design method proposed in the present invention, a superconducting quadplexer with an operating frequency of about 10GHz was designed. Figure 8 shown. Figure 8Port 1 is the common input port of the multiplexer, and ports 2, 3, 4, and 5 are the output ports of the filter circuits of each frequency band. The design results of the S21 parameters of each frequency band of the superconducting multiplexer are shown in Figure 1. Fig. 9 As shown, the passband characteristics of each frequency band are consistent, and the suppression degree of each frequency band circuit in other frequency bands is high.

[0090] The design method of multi-branch coupling circuit at the input end of microwave multiplexer. It includes the step-by-step design method of the electrical length of multi-branch microstrip lines between the input port of the multiplexer and the filter circuits of each frequency band; the design and iterative optimization method of the input microstrip circuit of the adjacent filter circuit; the design method of multi-branch microstrip circuit using the first resonator in each frequency band; the design method of the impedance poles of filters in different frequency bands; the selection and optimization design method of the access point of the newly added secondary filter circuit in the upper filter circuit, etc.

[0091] Figure 6 In TL1, TL2, TL3, TL4 and TL 12 TL 23 TL 34 During the impedance matching adjustment process of each microstrip line segment, it is necessary to simulate the channel A filter, channel B filter, channel C filter, and channel D filter together with each microstrip line segment. The simulation workload is large, and the frequency response characteristics obtained by simulation are prone to divergence. In the design method proposed in this application, each channel filter only uses the first-stage (first section) resonator to simulate with the microstrip line, such as Figure 7 As shown. The input impedance characteristics of the first-section resonator can be used as an approximation of the input impedance characteristics of the entire channel filter, which can have high accuracy and high simulation efficiency in the circuit simulation process and can obtain certain simulation results. This is the so-called "multi-branch microstrip circuit design method of the first-section resonator".

[0092] In the impedance matching process of different channel filters, if f A 、f B 、f C 、f D The impedance matching adjustment for all signals frequency by frequency is a huge workload and it is impossible to complete the simulation. This technology proposes a "method for designing impedance poles of filters in different frequency bands" with the center frequency f of the four passbands. A0 、f B0 、f C0 、f D0 To match the adjustment target, the microstrip line in front of each channel filter is matched and tuned at these four target frequency points. Taking the first step of impedance matching as an example, from the reference point C, first adjust the length of TL3 for impedance matching, and only let f C The frequency band signal enters the channel C filter on the right, while the center frequency of the channel D filter is f D0, through the TL3 microstrip line adjustment, channel C filter for this frequency f D0 It shows a completely suppressed impedance pole characteristic, thus achieving f D The frequency band signal cannot enter the target of the filter on the right channel C. Other microstrip lines use similar impedance pole tuning methods and processes, the difference is that the frequency of the high impedance point is different.

[0093] This application adopts a single-band filter circuit design method. It includes an asymmetric superconducting resonator structure suitable for high-frequency microwave multiplexers, which has the characteristics of electromagnetic field concentration in the resonator pattern, which is conducive to improving the isolation between different frequency bands of the multiplexer; two coupling structures and coupling modes between adjacent resonators, mainly electric field coupling and magnetic field coupling; capacitive coupling is used between the open end of the resonator and the input and output feeder, and the bending structure at the end of the feeder is used to fine-tune the external coupling strength of the filter.

[0094] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0095] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An asymmetric superconducting resonator, characterized in that: The asymmetric superconducting resonator comprises: a first microstrip line, a second microstrip line, a third microstrip line, a fourth microstrip line, a fifth microstrip line, a sixth microstrip line and a seventh microstrip line; The first portion of the microstrip line, the third portion of the microstrip line, the fifth portion of the microstrip line and the seventh portion of the microstrip line are parallel to each other, and the length of the first portion of the microstrip line is the same as the length of the third portion of the microstrip line, and the length of the fifth portion of the microstrip line is the same as the length of the seventh portion of the microstrip line; the length of the first portion of the microstrip line is greater than the length of the fifth portion of the microstrip line; The second portion of the microstrip line, the fourth portion of the microstrip line and the sixth portion of the microstrip line are parallel to each other; The first portion of the microstrip line is perpendicular to the second portion of the microstrip line, and one end of the first portion of the microstrip line is connected to one end of the second portion of the microstrip line; the other end of the second portion of the microstrip line is connected to one end of the third portion of the microstrip line, and the third portion of the microstrip line is perpendicular to the second portion of the microstrip line; The other end of the third microstrip line is connected to one end of the fourth microstrip line, and the third microstrip line is perpendicular to the fourth microstrip line; the other end of the fourth microstrip line is connected to one end of the fifth microstrip line, and the fourth microstrip line is perpendicular to the fifth microstrip line; the other end of the fifth microstrip line is connected to one end of the sixth microstrip line, and the fifth microstrip line is perpendicular to the sixth microstrip line; the other end of the sixth microstrip line is connected to one end of the seventh microstrip line; the sixth microstrip line is perpendicular to the seventh microstrip line; The spacing between the first portion of the microstrip line and the seventh portion of the microstrip line, the spacing between the seventh portion of the microstrip line and the fifth portion of the microstrip line, the spacing between the third portion of the microstrip line and the fifth portion of the microstrip line, and the spacing between the second portion of the microstrip line and the sixth portion of the microstrip line are all the same.

2. The asymmetric superconducting resonator according to claim 1, characterized in that: The length of the first portion of the microstrip line is 1.56 mm.

3. The asymmetric superconducting resonator according to claim 1, characterized in that: The length of the fifth portion of the microstrip line is 0.96 mm.

4. The asymmetric superconducting resonator according to claim 1, characterized in that: The distance between the first portion of microstrip line and the seventh portion of microstrip line is 0.3 mm.

5. The asymmetric superconducting resonator according to claim 1, characterized in that: The line widths corresponding to the first microstrip line, the second microstrip line, the third microstrip line, the fourth microstrip line, the fifth microstrip line, the sixth microstrip line and the seventh microstrip line are all the same; the line width is 0.3 mm.

6. An asymmetric superconducting resonator coupled filter, characterized in that: The asymmetric superconducting resonator coupling filter comprises: an input feeder, an output feeder and a coupling structure; the coupling structure is obtained by performing electric field coupling or magnetic field coupling on the asymmetric superconducting resonator according to any one of claims 1 to 5; The input feeder is connected to one end of the coupling structure; the output feeder is connected to the other end of the coupling structure; The input feed line consists of a straight structure and a bent structure; the straight structure is perpendicular to and connected to the bent structure; the bent structure is used to adjust the coupling degree.

7. The asymmetric superconducting resonator coupled filter according to claim 6, characterized in that: The coupling structure includes at least one group of resonators; each group of resonators includes two asymmetric superconducting resonators; The two asymmetric superconducting resonators are symmetrically arranged at a set interval.

8. The asymmetric superconducting resonator coupled filter according to claim 7, characterized in that: If the capacitance regions of the two asymmetric superconducting resonators are symmetrically arranged according to the set interval, electric field coupling is performed; the capacitance region is the opening region where the first part of the microstrip line and the seventh part of the microstrip line are located; If the inductance regions of the two asymmetric superconducting resonators are symmetrically arranged according to the set interval, magnetic field coupling is performed; the inductance region is a folded region after removing the capacitance region.

9. A microwave multiplex filter, characterized in that: The microwave multiplex filter comprises a plurality of asymmetric superconducting resonator coupled filters as claimed in any one of claims 6 to 8; A plurality of the asymmetric superconducting resonator coupling resonators are connected via microstrip lines.

10. The microwave multiplex filter according to claim 9, characterized in that: The length of the microstrip line is iteratively optimized by using a multi-branch coupling method to achieve impedance matching, and filtering performance simulation is performed based on simulation software to achieve passband matching.

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