Barlow structure

Abstract

This application provides a balun structure, which includes a substrate and a first inductor, a second inductor, a third inductor, and a fourth inductor disposed within the substrate. An input port, a first output port, a second output port, and a ground port are provided on the surface of the substrate. One end of the first inductor is electrically connected to the input port, and the other end is electrically connected to the ground port. The second inductor is coupled to the first inductor, with one end electrically connected to the ground port and the other end electrically connected to the first output port. The third inductor has both ends electrically connected to the ground port. The fourth inductor is disposed within the substrate and coupled to the third inductor, with one end electrically connected to the input port and the other end electrically connected to the second output port. The balun structure of this application can effectively reduce production costs, has a small size, low loss, and excellent amplitude and phase characteristics.

Description

Technical Field

[0001] This application belongs to the field of electronic components, and more specifically, relates to a balun structure. Background Technology

[0002] With the rapid development of electronic circuit technology and electronic component packaging technology, people are placing increasingly higher demands on the miniaturization of electronic products. A balun, an abbreviation for a balun converter, not only performs signal conversion between unbalanced and balanced ports but also generally has impedance transformation capabilities. LTCC (Low Temperature Co-fired Ceramic) baluns have become an important form of passive balun due to their advantages such as simple implementation, low cost, compact structure, good consistency, and low noise figure. In the rapid development of microwave technology, they have become one of the main passive microwave components, widely used in antenna feed networks, differential amplifiers, balanced mixers, and other systems requiring differential circuits. As electronic systems continue to develop towards miniaturization, lightweighting, and high performance, higher demands are placed on the size and performance of devices. Existing multilayer chip baluns suffer from severe parasitic interference at ultra-high frequencies, making it difficult to achieve excellent frequency characteristics and exhibiting poor amplitude and phase characteristics. Summary of the Invention

[0003] The purpose of this application is to provide a balun structure to solve the technical problems of severe parasitic interference at ultra-high frequencies, making it difficult to achieve excellent frequency characteristics and poor amplitude and phase characteristics in the prior art.

[0004] To achieve the above objectives, the technical solution adopted in this application is: to provide a balun structure, which includes:

[0005] A substrate, the surface of which is provided with an input port, a first output port, a second output port and a ground port;

[0006] A first inductor is disposed in the substrate. One end of the first inductor is electrically connected to the input port, and the other end is electrically connected to the ground port. The first inductor includes a first inductor section and a second inductor section, which are spaced apart and connected in parallel.

[0007] A second inductor is disposed in the substrate and coupled to the first inductor. One end of the second inductor is electrically connected to the ground port, and the other end is electrically connected to the first output port. The second inductor is located between the first inductor and the second inductor.

[0008] A third inductor is disposed in the substrate and electrically connected to a ground port at both ends. It includes a third inductor and a fourth inductor, which are spaced apart and connected in parallel.

[0009] A fourth inductor is disposed within the substrate and coupled to the third inductor. One end of the fourth inductor is electrically connected to the input port, and the other end is electrically connected to the second output port. The fourth inductor is located between the third inductor and the fourth inductor.

[0010] Optionally, the first inductor, the second inductor, the third inductor, and the fourth inductor are all planar spiral inductors with the same winding direction;

[0011] The first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor are arranged sequentially along the height direction of the substrate.

[0012] Optionally, the substrate is provided with a ground electrode, a first output electrode and a second output electrode. The ground electrode is electrically connected to the ground port, the first inductor, the second inductor and the third inductor. The first output electrode is electrically connected to the first output port and the second inductor. The second output electrode is electrically connected to the second output port and the fourth inductor.

[0013] The first output electrode and the second output electrode are spaced apart, and the second output electrode and the ground electrode are located on the same plane;

[0014] The grounding electrode, the first output electrode, and the second output electrode are all made of silver, and the thickness of the grounding electrode, the first output electrode, and the second output electrode is all in the range of 7-13 μm.

[0015] Optionally, the substrate is provided with a first metal hole, a second metal hole, a third metal hole, and a fourth metal hole. The first metal hole is electrically connected to the ground electrode, the second inductor, the third inductor, and the fourth inductor. The second metal hole is electrically connected to the second inductor and the first output electrode. The third metal hole is electrically connected to the first inductor, the second inductor, the third inductor, and the fourth inductor. The fourth metal hole is electrically connected to the fourth inductor and the second output electrode.

[0016] The axial directions of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are all in the height direction of the substrate, and the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are arranged at intervals.

[0017] Optionally, a capacitor is further provided in the substrate, one end of which is electrically connected to the first output electrode and the other end of which is electrically connected to the second output electrode;

[0018] The capacitor includes a first capacitor section and a second capacitor section arranged opposite each other, with the first capacitor section and the second capacitor section spaced apart. The first capacitor section and the first output electrode are integrally formed, and the second capacitor section and the second output electrode are integrally formed.

[0019] Optionally, the input port, the first output port, the second output port, and the ground port are all three-layer metal structures, which include a silver layer, a nickel layer, and a tin layer. The silver layer is close to the substrate, the tin layer is away from the substrate, and the nickel layer is located between the silver layer and the tin layer.

[0020] Optionally, the diameters of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are all in the range of 0.1mm-0.15mm;

[0021] The first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor are all composed of quarter-wavelength lines;

[0022] The wire diameter of the first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor is 85 μm.

[0023] Optionally, the substrate is a rectangular ceramic substrate with a length of 3.2 mm, a width of 1.6 mm, and a height of 0.9 mm.

[0024] Optionally, the passband frequency of the balun structure is 3400-4700MHz, and the insertion loss within the passband is ≤1.2dB;

[0025] The amplitude imbalance of the balun structure is ≤1.2dB, and the phase imbalance of the balun structure is ≤10°.

[0026] A method for manufacturing a balun structure includes the following steps:

[0027] S101: Provide a first diaphragm, and print a first output electrode and a first capacitor portion on the first diaphragm;

[0028] S102: A second diaphragm is stacked on the first diaphragm, and a through hole is provided on the second diaphragm corresponding to the position of the second metal hole. The through hole on the second diaphragm is metallized, and a ground electrode, a second output electrode, and a second capacitor are printed on the second diaphragm.

[0029] S103: A third diaphragm is stacked on the second diaphragm. The third diaphragm has four through holes respectively corresponding to the positions of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole. The through holes on the third diaphragm are metallized, and the first inductor part is printed on the third diaphragm.

[0030] S104: A fourth diaphragm is stacked on the third diaphragm. The fourth diaphragm has three through holes respectively corresponding to the positions of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole. The through holes on the fourth diaphragm are metallized, and the second inductor is printed on the fourth diaphragm.

[0031] S105: A fifth diaphragm is stacked on the fourth diaphragm. The fifth diaphragm has four through holes respectively corresponding to the positions of the first metal hole, the third metal hole, and the fourth metal hole. The through holes on the fifth diaphragm are metallized. The second inductor portion is printed on the fifth diaphragm.

[0032] S106: A sixth diaphragm is stacked on the fifth diaphragm. The sixth diaphragm has three through holes respectively corresponding to the positions of the first metal hole, the third metal hole, and the fourth metal hole. The through holes on the sixth diaphragm are metallized, and the third inductor is printed on the sixth diaphragm.

[0033] S107: A seventh diaphragm is stacked on the sixth diaphragm. Three through holes are respectively provided on the seventh diaphragm at the positions corresponding to the first metal hole, the third metal hole, and the fourth metal hole. The through holes on the seventh diaphragm are metallized, and the fourth inductor is printed on the seventh diaphragm.

[0034] S108: An eighth diaphragm is stacked on the seventh diaphragm. Two through holes are respectively provided on the eighth diaphragm at the positions corresponding to the first metal hole and the third metal hole. The through holes on the eighth diaphragm are metallized. The fourth inductor is printed on the eighth diaphragm.

[0035] S109: A ninth diaphragm is stacked on the eighth diaphragm, and a mark is printed on the ninth diaphragm.

[0036] The beneficial effects of the balun structure provided in this application embodiment are as follows: Compared with the prior art, the balun structure in this application embodiment, based on the transformer principle, is composed of six inductor coils (first inductor, second inductor, third inductor, fourth inductor, and fourth inductor) connected in series and parallel. This effectively reduces the complexity and sensitivity of the product manufacturing process, improves the yield rate, reduces production costs, and features small size, low loss, and excellent amplitude and phase characteristics, facilitating integration with other circuits. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A schematic diagram of the balun structure provided in the embodiments of this application;

[0039] Figure 2 This is a schematic diagram of the internal structure of the balun structure provided in the embodiments of this application;

[0040] Figure 3 A perspective view of the balun structure provided in the embodiments of this application;

[0041] Figure 4 Equivalent circuit diagram of the balun structure provided in the embodiments of this application;

[0042] Figure 5 This is a schematic diagram of the structure of the first diaphragm of the balun structure provided in the embodiments of this application;

[0043] Figure 6 This is a schematic diagram of the structure of the second membrane of the balun structure provided in the embodiments of this application;

[0044] Figure 7 A schematic diagram of the third diaphragm of the balun structure provided in the embodiments of this application;

[0045] Figure 8 This is a schematic diagram of the fourth membrane of the balun structure provided in the embodiments of this application;

[0046] Figure 9 This is a schematic diagram of the fifth membrane of the balun structure provided in the embodiments of this application;

[0047] Figure 10 A schematic diagram of the sixth membrane of the balun structure provided in the embodiments of this application;

[0048] Figure 11A schematic diagram of the structure of the seventh membrane of the balun structure provided in the embodiments of this application;

[0049] Figure 12 A schematic diagram of the eighth membrane of the balun structure provided in the embodiments of this application;

[0050] Figure 13 Insertion loss curves for the balun structure provided in the embodiments of this application;

[0051] Figure 14 The amplitude imbalance curve of the balun structure provided in the embodiments of this application;

[0052] Figure 15 The phase imbalance curve of the balun structure provided in the embodiments of this application;

[0053] Figure 16 A flowchart illustrating a method for manufacturing a balun structure as provided in an embodiment of this application.

[0054] The following are the labeling elements in the figure:

[0055] 1. Matrix;

[0056] 11. Input port; 12. First output port; 13. Second output port; 14. Ground port; 15. No-load terminal; 16. Ground electrode;

[0057] 171. First output electrode; 172. Second output electrode;

[0058] 181. First metal hole; 182. Second metal hole; 183. Third metal hole; 184. Fourth metal hole;

[0059] 191. First capacitor section; 192. Second capacitor section;

[0060] 21. First inductor;

[0061] 211. First inductor section; 212. Second inductor section;

[0062] 22. Second inductor;

[0063] 23. Third inductor;

[0064] 231. Third inductor section; 232. Fourth inductor section;

[0065] 24. Fourth inductor;

[0066] 31. First membrane; 32. Second membrane; 33. Third membrane; 34. Fourth membrane; 35. Fifth membrane; 36. Sixth membrane; 37. Seventh membrane; 38. Eighth membrane. Detailed Implementation

[0067] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and are not intended to limit the scope of this application.

[0068] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0069] It should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0070] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0071] In the field of communications, frequency bands refer to the range of electromagnetic wave frequencies, measured in Hz. Based on frequency magnitude, they can be divided into: Very Low Frequency (VLF) 3kHz–30kHz, corresponding to very long waves (100km–10km); Low Frequency (LF) 30kHz–300kHz, corresponding to long waves (10km–1km); Intermediate Frequency (MF) 300kHz–3000kHz, corresponding to medium waves (1000m–100m); High Frequency (HF) 3MHz–30MHz, corresponding to short waves (100m–10m); Very High Frequency (VHF) 30MHz–300MHz, corresponding to meter waves (10m–1m); and Ultra High Frequency (UHF) 300MHz–3000MHz, corresponding to decimeter waves (100cm–10cm). Ultra-high frequency (SHF) 3GHz~30GHz, corresponding to electromagnetic wave wavelengths of 10cm~1cm (centimeter waves). Extremely high frequency (EHF) 30GHz~300GHz, corresponding to electromagnetic wave wavelengths of 10mm~1mm (millimeter waves). Ultra-high frequency 300GHz~3000GHz, corresponding to electromagnetic wave wavelengths of 1mm~0.1mm (micrometer waves).

[0072] Please refer to the following: Figure 1 , Figure 2 , Figure 3 and Figure 4 The balun structure provided in the embodiments of this application will now be described. The balun structure includes a substrate 1, a first inductor 21, a second inductor 22, a third inductor 23, and a fourth inductor 24. An input port 11, a first output port 12, a second output port 13, an unloaded terminal 15, and two ground ports 14 are provided on the surface of the substrate 1. The first inductor 21 is disposed within the substrate 1. One end of the first inductor 21 is electrically connected to the input port 11, and the other end is electrically connected to the ground port 14. The first inductor 21 includes a first inductor portion 211 and a second inductor portion 212, which are spaced apart and connected in parallel. The second inductor 22 is disposed within the substrate 1 and coupled to the first inductor 21. One end of the second inductor 22 is electrically connected to the ground port 14, and the other end is electrically connected to the first output port 12. The second inductor 22 is located between the first inductor section 211 and the second inductor section 212. The printed patterns of the first inductor section 211 and the second inductor section 212 are identical, which simplifies the molding process. The first inductor section 211, the second inductor 22, and the second inductor section 212 form a coupling group, which transmits input energy to the output terminal through inductive spatial coupling and avoids interference from other active components.

[0073] The third inductor 23 is disposed within the substrate 1, and its two ends are electrically connected to the ground port 14. It includes a third inductor section 231 and a fourth inductor section 232, which are spaced apart and connected in parallel. The fourth inductor 24 is disposed within the substrate 1 and coupled to the third inductor 23. One end of the fourth inductor 24 is electrically connected to the input port 11, and the other end is electrically connected to the second output port 13. The fourth inductor 24 is located between the third inductor section 231 and the fourth inductor section 232. The printed patterns of the third inductor section 231 and the fourth inductor section 232 are identical, simplifying the molding process. The third inductor section 231, the fourth inductor 24, and the fourth inductor section 232 form a coupling group, transmitting input energy to the output terminal through inductive spatial coupling and avoiding interference from other active components.

[0074] Please refer to Figure 13 Trc1 window 1, Sds12: indicates insertion loss; Mag 10dB / Ref 0dB indicates accuracy in 10dB increments; Cal int Offs: calibration. Ch1 Start 3GHz Pwr-10dBm Bw 10kHz Stop 5GHz: test frequency range from 3GHz to 5GHz, step size is 10kHz. At ultra-high frequencies of 3400MHz-4700MHz, the insertion loss within the passband is ≤1.2dB. The insertion loss is maximum at 4700MHz, reaching 1.1512dB.

[0075] Please refer to Figure 14 Trc2 window 2, lmb12 dB: Product amplitude imbalance, Mag 10dB / Ref0dB, MathOffs: Accuracy is in 10dB increments. Ch1 Start 3GHz Pwr-10dBm Bw 10kHz Stop 5GHz: Test frequency range from 3GHz to 5GHz, step size is 10kHz. At ultra-high frequencies of 3400MHz-4700MHz, amplitude imbalance is ≤1.2dB. The amplitude imbalance is maximum at a passband frequency of 4700MHz, at 0.9095dB.

[0076] Please refer to Figure 15Trc3 window 3, lmb12 Phase: indicates phase imbalance, 45 / Ref 0Math Offs: indicates accuracy in 45-degree increments. Ch1 Start 3GHz Pwr-10dBm Bw 10kHz Stop5GHz: The test frequency range is from 3GHz to 5GHz, with a step size of 10kHz. At ultra-high frequencies of 3400MHz-4700MHz, the phase imbalance is ≤10°. The phase imbalance is maximum at 4700MHz, reaching 9.37°.

[0077] Therefore, this balun structure has low insertion loss and excellent amplitude and phase characteristics.

[0078] Based on the transformer principle, the structure consists of six inductor coils (first inductor 211, second inductor 22, second inductor 212, third inductor 231, fourth inductor 24, and fourth inductor 232) connected in series and parallel. This effectively reduces the complexity and sensitivity of the product manufacturing process, increases yield, lowers production costs, and features small size, low loss, and excellent amplitude and phase characteristics, making it easy to integrate with other circuits.

[0079] The first inductor 21, the second inductor 22, the third inductor 23, and the fourth inductor 24 are all planar spiral inductors with the same winding direction. Planar spiral inductors can maximize space utilization, and the parasitic capacitance of the planar spiral inductor can effectively shorten the length of the coupling line.

[0080] The first inductor 211, the second inductor 22, the second inductor 212, the third inductor 231, the fourth inductor 24, and the fourth inductor 232 are arranged sequentially along the height direction of the substrate 1. This efficient use of the spatial distribution of the substrate 1's height facilitates the miniaturization of the balun structure.

[0081] Reference Figure 3 , Figure 6 and Figure 7 The substrate 1 contains a ground electrode 16, a first output electrode 171, and a second output electrode 172. The ground electrode 16 is electrically connected to a ground port 14, a first inductor 21, a second inductor 22, and a third inductor 23. The first output electrode 171 is electrically connected to a first output port 12 and a second inductor 22. The second output electrode 172 is electrically connected to a second output port 13 and a fourth inductor 24. Only one ground electrode 16 is needed, resulting in high space utilization and facilitating the miniaturization of the balun structure.

[0082] The grounding electrode 16 is triangular in shape and has a triangular hole inside. The second metal hole 182 passes through the hole inside the grounding electrode 16. This ensures that the grounding electrode 16 can conduct through the first metal hole 181 and the third metal hole 183 without interfering with the second metal hole 182.

[0083] The first output electrode 171 and the second output electrode 172 are spaced apart, facilitating the connection of a capacitor in parallel between the first output electrode 171 and the second output electrode 172 for filtering noise signals. The second output electrode 172 and the ground electrode 16 are located on the same plane. Full utilization of the internal space of the substrate 1 is beneficial for the miniaturization of the balun structure.

[0084] The grounding electrode 16, the first output electrode 171, and the second output electrode 172 are made of silver paste. The silver paste is sintered at a temperature of 860℃-900℃, contains 85±5% silver, and has a silver layer thickness of 10μm±3μm. The material can be silver, but copper can also be used to ensure excellent conductivity of the grounding electrode 16, the first output electrode 171, and the second output electrode 172.

[0085] The substrate 1 has a first metal hole 181, a second metal hole 182, a third metal hole 183, and a fourth metal hole 184. The first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184 are formed by coating the inner walls of the holes with molten metal. The first metal hole 181 is electrically connected to the ground electrode 16, the second inductor 22, the third inductor 231, and the fourth inductor 232. The second metal hole 182 is electrically connected to the second inductor 22 and the first output electrode 171. The third metal hole 183 is electrically connected to the first inductor 211, the second inductor 212, the third inductor 231, and the fourth inductor 232. The fourth metal hole 184 is electrically connected to the fourth inductor 24 and the second output electrode 172. By setting the first metal hole 181, the second metal hole 182, the third metal hole 183 and the fourth metal hole 184, the series and parallel connections between the first inductor 21, the second inductor 22, the third inductor 23, the fourth inductor 24, the ground electrode 16, the first output electrode 171 and the second output electrode 172 are ensured.

[0086] The axes of the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184 are all along the height direction of the substrate 1, and are spaced apart. The diameters of the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184 are all in the range of 0.1mm-0.15mm, making full use of the space in the substrate 1 and facilitating the miniaturization of the balun structure.

[0087] A capacitor is also provided inside the substrate 1. One end of the capacitor is electrically connected to the first output electrode 171, and the other end is electrically connected to the second output electrode 172. Connecting a capacitor in parallel between the first output electrode 171 and the second output electrode 172 can effectively filter noise signals.

[0088] The capacitor includes a first capacitor section 191 and a second capacitor section 192 arranged opposite each other, with the first capacitor section 191 and the second capacitor section 192 spaced apart. The first capacitor section 191 and the first output electrode 171 are integrally formed, and the second capacitor section 192 and the second output electrode 172 are integrally formed. The processing technology is simple, the cost is low, and the space can be reused.

[0089] Input port 11, first output port 12, second output port 13, and ground port 14 are all three-layer metal structures, consisting of a silver layer, a nickel layer, and a tin layer. The silver layer is close to the substrate 1, the tin layer is far from the substrate 1, and the nickel layer is located between the silver layer and the tin layer. This three-layer metal structure ensures the reliability of the product's soldering.

[0090] The first inductor 211, the second inductor 22, the second inductor 212, the third inductor 231, the fourth inductor 24, and the fourth inductor 232 are all composed of quarter-wavelength wire. The wire diameter of the first inductor 211, the second inductor 22, the second inductor 212, the third inductor 231, the fourth inductor 24, and the fourth inductor 232 is 85 μm.

[0091] Substrate 1 is made of low-temperature co-fired ceramic powder, sintered at 860℃-900℃, with a dielectric constant of 4.8-6.2 and a dielectric loss factor of tanα≤0.005. Substrate 1 is also made of low-temperature co-fired ceramic powder, sintered at 880℃, with a dielectric constant of 5.0 and a dielectric loss factor of tanα of 0.001. Substrate 1 is a rectangular ceramic substrate with a length of 3.2mm, a width of 1.6mm, and a height of 0.9mm.

[0092] This application provides a method for manufacturing a balun structure, referring to... Figure 16 A method for manufacturing a balun structure includes the following steps:

[0093] S101: A first diaphragm 31 is provided, and a first output electrode 171 and a first capacitor portion 191 are printed on the first diaphragm 31. (Refer to...) Figure 5 .

[0094] S102: A second diaphragm 32 is stacked on the first diaphragm 31. A through hole is provided on the second diaphragm 32 corresponding to the position of the second metal hole 182. The through hole on the second diaphragm 32 is metallized. A ground electrode 16, a second output electrode 172, and a second capacitor section 192 are printed on the second diaphragm 32. (Refer to...) Figure 6 .

[0095] S103: A third diaphragm 33 is stacked on the second diaphragm 32. Four through holes are respectively provided on the third diaphragm 33 at positions corresponding to the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184. The through holes on the third diaphragm 33 are metallized, and a first inductor section 211 is printed on the third diaphragm 33. (Refer to...) Figure 7 .

[0096] S104: A fourth diaphragm 34 is stacked on the third diaphragm 33. Three through holes are respectively provided on the fourth diaphragm 34 corresponding to the positions of the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184. The through holes on the fourth diaphragm 34 are metallized. A second inductor 22 is printed on the fourth diaphragm 34. (Refer to...) Figure 8 .

[0097] S105: A fifth diaphragm 35 is stacked on the fourth diaphragm 34. Four through holes are respectively provided on the fifth diaphragm 35 corresponding to the positions of the first metal hole 181, the third metal hole 183, and the fourth metal hole 184. The through holes on the fifth diaphragm 35 are metallized. A second inductor section 212 is printed on the fifth diaphragm 35. (Refer to...) Figure 9 .

[0098] S106: A sixth diaphragm 36 is stacked on the fifth diaphragm 35. Three through holes are respectively provided on the sixth diaphragm 36 at positions corresponding to the first metal hole 181, the third metal hole 183, and the fourth metal hole 184. The through holes on the sixth diaphragm 36 are metallized. A third inductor section 231 is printed on the sixth diaphragm 36. (Refer to...) Figure 10 .

[0099] S107: A seventh diaphragm 37 is stacked on the sixth diaphragm 36. Three through holes are respectively provided on the seventh diaphragm 37 at positions corresponding to the first metal hole 181, the third metal hole 183, and the fourth metal hole 184. The through holes on the seventh diaphragm 37 are metallized. A fourth inductor 24 is printed on the seventh diaphragm 37. (Refer to...) Figure 11 .

[0100] S108: An eighth diaphragm 38 is stacked on the seventh diaphragm 37. Two through holes are respectively provided on the eighth diaphragm 38 at positions corresponding to the first metal hole 181 and the third metal hole 183. The through holes on the eighth diaphragm 38 are metallized. A fourth inductor section 232 is printed on the eighth diaphragm 38. (Refer to...) Figure 12 .

[0101] S109: Place the ninth membrane on top of the eighth membrane 38, and print a mark on the ninth membrane.

[0102] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A balun structure, characterized by, include: The substrate has an input port, a first output port, a second output port, and a grounding port on its outer surface. A first inductor is disposed in the substrate. One end of the first inductor is electrically connected to the input port, and the other end is electrically connected to the ground port. The first inductor includes a first inductor section and a second inductor section, which are spaced apart and connected in parallel. A second inductor is disposed in the substrate and coupled to the first inductor. One end of the second inductor is electrically connected to the ground port, and the other end is electrically connected to the first output port. The second inductor is located between the first inductor and the second inductor. A third inductor is disposed in the substrate and electrically connected to a ground port at both ends. It includes a third inductor and a fourth inductor, which are spaced apart and connected in parallel. A fourth inductor is disposed in the substrate and coupled to the third inductor. One end of the fourth inductor is electrically connected to the input port, and the other end is electrically connected to the second output port. The fourth inductor is located between the third inductor and the fourth inductor. The substrate is provided with a ground electrode, a first output electrode, and a second output electrode. The ground electrode is electrically connected to the ground port, the first inductor, the second inductor, and the third inductor. The first output electrode is electrically connected to the first output port and the second inductor. The second output electrode is electrically connected to the second output port and the fourth inductor. The ground electrode is triangular in shape. The first output electrode and the second output electrode are spaced apart, and the second output electrode and the ground electrode are located on the same plane.

2. The balun structure of claim 1, wherein, The first inductor, the second inductor, the third inductor, and the fourth inductor are all planar spiral inductors, and their winding directions are consistent. The first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor are arranged sequentially along the height direction of the substrate.

3. The balun structure of claim 1, wherein, The substrate is provided with a first metal hole, a second metal hole, a third metal hole, and a fourth metal hole. The first metal hole is electrically connected to the ground electrode, the second inductor, the third inductor, and the fourth inductor. The second metal hole is electrically connected to the second inductor and the first output electrode. The third metal hole is electrically connected to the first inductor, the second inductor, the third inductor, and the fourth inductor. The fourth metal hole is electrically connected to the fourth inductor and the second output electrode. The axial directions of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are all in the height direction of the substrate, and the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are arranged at intervals.

4. The balun structure of claim 1, wherein, A capacitor is also provided in the substrate, one end of which is electrically connected to the first output electrode and the other end of which is electrically connected to the second output electrode. The capacitor includes a first capacitor section and a second capacitor section arranged opposite each other, with the first capacitor section and the second capacitor section spaced apart. The first capacitor section and the first output electrode are integrally formed, and the second capacitor section and the second output electrode are integrally formed.

5. The balun structure as described in claim 1, characterized in that, The grounding electrode, the first output electrode, and the second output electrode are all made of silver, and the thickness of the grounding electrode, the first output electrode, and the second output electrode is all in the range of 7-13 μm.

6. The balun structure as described in claim 3, characterized in that, The diameters of the first metal hole, the second metal hole, the third metal hole, and the fourth metal hole are all in the range of 0.1mm-0.15mm; The first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor are all composed of quarter-wavelength lines; The wire diameter of the first inductor, the second inductor, the third inductor, the fourth inductor, and the fourth inductor is 85 μm.

7. The balun structure as described in any one of claims 1-6, characterized in that, The input port, the first output port, the second output port, and the ground port are all three-layer metal structures, which include a silver layer, a nickel layer, and a tin layer. The silver layer is close to the substrate, the tin layer is away from the substrate, and the nickel layer is located between the silver layer and the tin layer.

8. The balun structure as described in any one of claims 1-6, characterized in that, The substrate is a rectangular ceramic substrate with a length of 3.2 mm, a width of 1.6 mm, and a height of 0.9 mm.

9. The balun structure as described in any one of claims 1-6, characterized in that, The passband frequency of the balun structure is 3400-4700MHz, and the insertion loss within the passband is ≤1.2dB; The amplitude imbalance of the balun structure is ≤1.2dB, and the phase imbalance of the balun structure is ≤10°.

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