CN115242208A - Balun structure - Google Patents

Abstract

The application provides a balun structure, balun structure includes the base member and sets up the first inductor in the base member, the second inductor, third inductor and fourth inductor, be equipped with the input port on the base member surface, first output port, second output port and ground connection port, first inductor one end electric connection input port, other end electric connection ground connection port, the second inductor couples with first inductor, second inductor one end electric connection ground connection port, other end electric connection first output port, the third inductor, both ends electric connection ground connection port, the fourth inductor sets up in the base member, couple with the third inductor, fourth inductor one end electric connection input port, other end electric connection second output port. The balun structure of the embodiment of the application can effectively reduce the production cost, and is small in size, low in loss and excellent in amplitude and phase characteristics.

Description

Balun structure

Technical Field

The present application belongs to the field of electronic components, and more particularly, to a balun structure.

Background

With the rapid development of electronic circuit technology and electronic component packaging technology, people have raised higher and higher requirements for miniaturization of electronic products. Balun (Balun) is a transliteration of the english acronym Balun, and generally has an impedance transformation function in addition to performing the interconversion of signals from unbalanced ports to balanced ports. The LTCC (Low Temperature Co-fired Ceramic) balun has the advantages of simple realization, low cost, compact structure, good consistency, low noise coefficient and the like, and becomes an important form of the prior passive balun. In the rapid development of microwave technology, the microwave resonator has become one of the leading roles of passive microwave devices, and is widely applied to systems requiring differential circuits, such as a feed network of an antenna, a differential amplifier, and a balanced mixer. With the continuous development of electronic systems toward miniaturization, light weight and high performance, higher requirements are put on the size and performance of devices. The existing laminated balun has the defects that excellent frequency characteristics are difficult to realize due to serious parasitic interference under ultrahigh frequency, and the amplitude phase characteristics are poor.

Disclosure of Invention

An object of the embodiments of the present application is to provide a balun structure, so as to solve the technical problems that the parasitic interference is hard to realize the excellent frequency characteristic and the amplitude-phase characteristic is poor under the ultra-high frequency existing in the prior art.

In order to achieve the purpose, the technical scheme adopted by the application is as follows: there is provided a balun structure comprising:

the device comprises a base body, a first input port, a second input port, a first output port and a second output port, wherein the surface of the base body is provided with the input port, the first output port, the second output port and a grounding port;

the first inductor is arranged in the substrate, one end of the first inductor is electrically connected with the input port, the other end of the first inductor is electrically connected with the grounding port, the first inductor comprises a first inductance part and a second inductance part, the first inductance part and the second inductance part are arranged at intervals, and the first inductance part and the second inductance part are connected in parallel;

a second inductor disposed in the substrate and coupled to the first inductor, wherein one end of the second inductor is electrically connected to the ground port, and the other end of the second inductor is electrically connected to the first output port, and the second inductor is located between the first inductor part and the second inductor part;

the third inductor is arranged in the substrate, two ends of the third inductor are electrically connected with the grounding port, the third inductor comprises a third inductor part and a fourth inductor part, the third inductor part and the fourth inductor part are arranged at intervals, and the third inductor part and the fourth inductor part are connected in parallel;

and the fourth inductor is arranged in the substrate and coupled with the third inductor, one end of the fourth inductor is electrically connected with the input port, the other end of the fourth inductor is electrically connected with the second output port, and the fourth inductor is positioned between the third inductance part and the fourth inductance part.

Optionally, the first inductor, the second inductor, the third inductor, and the fourth inductor are all planar spiral inductors, and the winding directions are the same;

the first inductance part, the second inductor, the second inductance part, the third inductance part, the fourth inductor and the fourth inductance part are sequentially arranged along the height direction of the base body.

Optionally, a ground electrode, a first output electrode, and a second output electrode are disposed inside the base, 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, and the second output electrode is electrically connected to the second output port and the fourth inductor;

the first output electrode and the second output electrode are arranged at intervals, and the second output electrode and the grounding electrode are positioned on the same plane;

the grounding electrode, the first output electrode and the second output electrode are made of silver, and the thickness ranges of the grounding electrode, the first output electrode and the second output electrode are 7-13 mu m.

Optionally, a first metal hole, a second metal hole, a third metal hole and a fourth metal hole are disposed in the substrate, 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, and 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 the height direction of the base body, and the first metal hole, the second metal hole, the third metal hole and the fourth metal hole are arranged at intervals.

Optionally, a capacitor is further disposed in the substrate, one end of the capacitor is electrically connected to the first output electrode, and the other end of the capacitor is electrically connected to the second output electrode;

the capacitor comprises a first capacitor part and a second capacitor part which are opposite to each other, the first capacitor part and the second capacitor part are arranged at intervals, the first capacitor part and the first output electrode are integrally formed, and the second capacitor part and the second output electrode are integrally formed.

Optionally, the input port, the first output port, the second output port, and the ground port are all three-layer metal structures, each three-layer metal structure includes a silver layer, a nickel layer, and a tin layer, the silver layer is close to the substrate, the tin layer is far away from the substrate, and the nickel layer is located between the silver layer and the tin layer.

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;

the first, second, third, fourth and fourth inductive portions are all comprised of quarter-wave lines;

the first inductance part, the second inductance part, the third inductance part, the fourth inductance part, and the fourth inductance part have a wire diameter of 85 μm.

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

Optionally, the passband frequency of the balun structure is 3400-4700MHz, and the insertion loss in the passband is less than or equal to 1.2dB;

the amplitude unbalance degree of the balun structure is less than or equal to 1.2dB, and the phase unbalance degree of the balun structure is less than or equal to 10 degrees.

A method of fabricating a balun structure comprising the steps of:

s101: providing a first diaphragm, and printing a first output electrode and a first capacitor part on the first diaphragm;

s102: stacking a second diaphragm on the first diaphragm, wherein through holes are formed in the second diaphragm corresponding to second metal holes, the through holes in the second diaphragm are metalized, and a grounding electrode, a second output electrode and a second capacitor part are printed on the second diaphragm;

s103: stacking a third membrane on the second membrane, wherein four through holes are respectively formed in the third membrane corresponding to the first metal hole, the second metal hole, the third metal hole and the fourth metal hole, the through holes in the third membrane are metalized, and the first inductance part is printed on the third membrane;

s104: stacking a fourth diaphragm on the third diaphragm, wherein three through holes are respectively formed in the fourth diaphragm corresponding to the first metal hole, the second metal hole, the third metal hole and the fourth metal hole, the through holes in the fourth diaphragm are metalized, and the second inductor is printed on the fourth diaphragm;

s105: stacking a fifth diaphragm on the fourth diaphragm, wherein four through holes are respectively formed in the positions, corresponding to the first metal hole, the third metal hole and the fourth metal hole, of the fifth diaphragm, the through holes in the fifth diaphragm are metalized, and the second inductance part is printed on the fifth diaphragm;

s106: stacking a sixth diaphragm on the fifth diaphragm, wherein three through holes are respectively formed in the sixth diaphragm corresponding to the first metal hole, the third metal hole and the fourth metal hole, the through holes in the sixth diaphragm are metalized, and the third inductance part is printed on the sixth diaphragm;

s107: stacking a seventh diaphragm on the sixth diaphragm, wherein three through holes are respectively formed in the seventh diaphragm corresponding to the first metal hole, the third metal hole and the fourth metal hole, the through holes in the seventh diaphragm are metalized, and the fourth inductor is printed on the seventh diaphragm;

s108: and stacking an eighth diaphragm on the seventh diaphragm, wherein two through holes are respectively formed in the eighth diaphragm corresponding to the first metal hole and the third metal hole, the through holes in the eighth diaphragm are metalized, and the fourth inductance part is printed on the eighth diaphragm.

S109: and stacking a ninth film sheet on the eighth film sheet, and printing a mark on the ninth film sheet.

The balun structure provided by the embodiment of the application has the beneficial effects that: compared with the prior art, the balun structure of the embodiment of the application is formed by connecting six inductance coils (a first inductance part, a second inductance part, a third inductance part, a fourth inductance part and a fourth inductance part) in series and in parallel based on the structure of the transformer principle. The method can effectively reduce the complexity and the sensitivity of the production process of the product, improve the rate of finished products, reduce the production cost, has small volume, low loss and excellent amplitude and phase characteristics, and is beneficial to the integration with other circuits.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a balun structure provided in an embodiment of the present application;

fig. 2 is a schematic diagram of an internal structure of a balun structure provided in an embodiment of the present application;

fig. 3 is a perspective view of a balun structure provided in an embodiment of the present application;

fig. 4 is an equivalent circuit diagram of a balun structure provided in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a first diaphragm of a balun structure provided in an embodiment of the present application;

fig. 6 is a schematic structural diagram of a second diaphragm of a balun structure provided in an embodiment of the present application;

fig. 7 is a schematic structural diagram of a third diaphragm of a balun structure provided in an embodiment of the present application;

fig. 8 is a schematic structural diagram of a fourth diaphragm of a balun structure provided in an embodiment of the present application;

fig. 9 is a schematic structural diagram of a fifth diaphragm of a balun structure provided in an embodiment of the present application;

fig. 10 is a schematic structural diagram of a sixth diaphragm of a balun structure provided in an embodiment of the present application;

fig. 11 is a schematic structural diagram of a seventh diaphragm of a balun structure provided in an embodiment of the present application;

fig. 12 is a schematic structural diagram of an eighth diaphragm of a balun structure provided in an embodiment of the present application;

fig. 13 is an insertion loss curve of a balun structure provided in an embodiment of the present application;

fig. 14 is an amplitude imbalance curve of the balun structure provided in the embodiment of the present application;

fig. 15 is a phase imbalance curve of the balun structure provided in the embodiment of the present application;

fig. 16 is a flowchart of a method for manufacturing a balun structure according to an embodiment of the present application.

Wherein, in the figures, the various reference numbers:

1. a substrate;

11. an input port; 12. a first output port; 13. a second output port; 14. a ground port; 15. a no-load end; 16. a ground electrode;

171. a first output electrode; 172. a second output electrode;

181. a first metal hole; 182. a second metal hole; 183. a third metal hole; 184. a fourth metal hole;

191. a first capacitance section; 192. a second capacitance section;

21. a first inductor;

211. a first inductance section; 212. a second inductance section;

22. a second inductor;

23. a third inductor;

231. a third inductance section; 232. a fourth inductance section;

24. a fourth inductor;

31. a first diaphragm; 32. a second diaphragm; 33. a third diaphragm; 34. a fourth diaphragm; 35. a fifth diaphragm; 36. a sixth diaphragm; 37. a seventh diaphragm; 38. and an eighth membrane.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present application clearer, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present application and are not intended to limit the present application.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like, as used herein, refer to an orientation or positional relationship indicated in the drawings that is solely for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be considered as limiting the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or to implicitly indicate 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 the present application, "a plurality" means two or more unless specifically limited otherwise.

In the communication field, a frequency band refers to a frequency range of electromagnetic waves, and the unit is Hz, and according to the frequency, the frequency band can be divided into: the Very Low Frequency (VLF) is 3 kHz-30 kHz, and the wavelength of the corresponding electromagnetic wave is 100 km-10 km of very long wave. Low Frequency (LF) 30 kHz-300 kHz, and the wavelength of the corresponding electromagnetic wave is 10 km-1 km of long wave. The Medium Frequency (MF) is 300 kHz-3000 kHz, and the wavelength of the corresponding electromagnetic wave is 1000 m-100 m. High Frequency (HF) 3 MHz-30 MHz, and corresponding electromagnetic wave wavelength 100 m-10 m. The Very High Frequency (VHF) is 30 MHz-300 MHz, and the wavelength of the corresponding electromagnetic wave is 10 m-1 m. The Ultra High Frequency (UHF) is 300 MHz-3000 MHz, and the wavelength of the corresponding electromagnetic wave is 100 cm-10 cm of decimetric wave. Ultrahigh frequency (SHF) is 3 GHz-30 GHz, and the wavelength of corresponding electromagnetic waves is 10 cm-1 cm. The ultra high frequency (EHF) is 30 GHz-300 GHz, and the wavelength of the corresponding electromagnetic wave is 10 mm-1 mm. To 300 GHz-3000 GHz at high frequency, and the wavelength of the corresponding electromagnetic wave is 1mm-0.1 mm of the decimeter wave.

Referring to fig. 1, fig. 2, fig. 3 and fig. 4, a balun structure provided in an embodiment of the present application will now be described. The balun structure comprises a base 1, a first inductor 21, a second inductor 22, a third inductor 23 and a fourth inductor 24. The surface of the base body 1 is provided with an input port 11, a first output port 12, a second output port 13, a no-load port 15 and two ground ports 14. The first inductor 21 is disposed in the base 1, one end of the first inductor 21 is electrically connected to the input port 11, and the other end of the first inductor 21 is electrically connected to the ground port 14, the first inductor 21 includes a first inductance part 211 and a second inductance part 212, the first inductance part 211 and the second inductance part 212 are disposed at an interval, and the first inductance part 211 and the second inductance part 212 are connected in parallel. The second inductor 22 is disposed in the base 1 and coupled to the first inductor 21, one end of the second inductor 22 is electrically connected to the ground port 14, the other end is electrically connected to the first output port 12, and the second inductor 22 is located between the first inductance part 211 and the second inductance part 212. The printed patterns of the first and second inductance parts 211 and 212 are the same, so that the molding process can be simplified. The first inductor 211, the second inductor 22, and the second inductor 212 are a coupling group, which transfers the input energy to the output end through inductive spatial coupling and avoids interference of other active elements.

The third inductor 23 is disposed in the base 1, and both ends of the third inductor are electrically connected to the ground port 14, and includes a third inductance portion 231 and a fourth inductance portion 232, the third inductance portion 231 and the fourth inductance portion 232 are disposed at an interval, and the third inductance portion 231 and the fourth inductance portion 232 are connected in parallel. The fourth inductor 24 is disposed in the base 1 and coupled to the third inductor 23, one end of the fourth inductor 24 is electrically connected to the input port 11, the other end of the fourth inductor 24 is electrically connected to the second output port 13, and the fourth inductor 24 is located between the third inductance part 231 and the fourth inductance part 232. The third inductance part 231 and the fourth inductance part 232 have the same printed pattern, so that the molding process can be simplified. The third inductor 231, the fourth inductor 24 and the fourth inductor 232 are a coupling group, which transfers the input energy to the output end through inductive spatial coupling and avoids interference of other active elements.

Please refer to fig. 13, trc1 window 1, sds12: expressed as insertion loss, mag 10dB/Ref0dB expressed as: the precision is 10dB one, cal int Offs: and (6) calibrating. Ch1 Start 3GHz Pwr-10dBm Bw 10kHz Stop5GHz: the test frequency ranged from 3GHz to 5GHz, with a step size of 10kHz. Under the ultrahigh frequency of 3400MHz-4700MHz, the insertion loss in the pass band is less than or equal to 1.2dB. The insertion loss is maximum at a passband frequency of 4700MHz, which is 1.1512dB.

Referring to fig. 14, trc2 window 2, lmb12 dB: the amplitude unbalance of the product is as follows, mag 10dB/Ref0dB Math Offs: the accuracy is 10 dB. Ch1 Start 3GHzPwr-10dBm Bw 10kHzStop5GHz: the test frequency ranged from 3GHz to 5GHz with a step size of 10kHz. Under the ultrahigh frequency of 3400MHz-4700MHz, the amplitude unbalance degree is less than or equal to 1.2dB. When the passband frequency is 4700MHz, the amplitude imbalance is the largest, 0.9095dB.

Please refer to fig. 15, trc3 window 3, lmb12 Phase: indicating the degree of phase imbalance, 45/Ref 0Math Offs: indicating a precision of 45 degrees. Ch1 Start 3GHz Pwr-10dBm Bw 10kHz Stop5GHz: the test frequency ranged from 3GHz to 5GHz with a step size of 10kHz. Under the ultrahigh frequency of 3400MHz-4700MHz, the phase unbalance is less than or equal to 10 degrees. The phase imbalance is at a maximum of 9.37 ° when the passband frequency is 4700 MHz.

Therefore, the balun structure has a small insertion loss and excellent amplitude and phase characteristics.

The structure based on the transformer principle is composed of six inductance coils (a first inductance part 211, a second inductance part 22, a second inductance part 212, a third inductance part 231, a fourth inductance part 24, and a fourth inductance part 232) connected in series and parallel. The method can effectively reduce the complexity and the sensitivity of the production process of the product, improve the rate of finished products, reduce the production cost, has small volume, low loss and excellent amplitude and phase characteristics, and is beneficial to the integration with other circuits.

The first inductor 21, the second inductor 22, the third inductor 23 and the fourth inductor 24 are all planar spiral inductors, and the winding directions are consistent. The planar spiral inductor can realize the maximum space utilization, and the parasitic capacitance of the planar spiral inductor is utilized, so that the length of the coupling line can be effectively shortened.

The first inductance section 211, the second inductance section 22, the second inductance section 212, the third inductance section 231, the fourth inductance section 24, and the fourth inductance section 232 are arranged in this order along the height direction of the base 1. The high spatial distribution of the substrate 1 is fully utilized, which is beneficial to the miniaturization of the balun structure.

Referring to fig. 3, 6 and 7, a ground electrode 16, a first output electrode 171 and a second output electrode 172 are disposed inside the base 1, the ground electrode 16 is electrically connected to the ground port 14, the first inductor 21, the second inductor 22 and the third inductor 23, the first output electrode 171 is electrically connected to the first output port 12 and the second inductor 22, and the second output electrode 172 is electrically connected to the second output port 13 and the fourth inductor 24. Only one grounding electrode 16 is needed, so that the space utilization rate is high, and the miniaturization of the balun structure is facilitated.

The ground electrode 16 has a triangular shape with a triangular hole formed therein, and the second metal hole 182 is formed through the hole in the ground electrode 16. The ground electrode 16 is secured to conduct the first metal via 181 and the third metal via 183 without interfering with the second metal via 182.

The first output electrode 171 and the second output electrode 172 are spaced apart from each other, so that a capacitor for filtering a noise signal is connected between the first output electrode 171 and the second output electrode 172 in parallel. The second output electrode 172 is located in the same plane as the ground electrode 16. The internal space of the matrix 1 is fully utilized, which is beneficial to the miniaturization of the balun structure.

The grounding electrode 16, the first output electrode 171 and the second output electrode 172 are made of silver paste, the sintering temperature of the silver paste is 860-900 ℃, the silver content of the silver paste is 85 +/-5%, and the thickness of the silver layer is 10 microns +/-3 microns. The material is provided as silver, and may be provided as copper, ensuring excellent conductivity of the ground electrode 16, the first output electrode 171, and the second output electrode 172.

A first metal hole 181, a second metal hole 182, a third metal hole 183 and a fourth metal hole 184 are arranged in the base body 1, and 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 metal molten pulp on the inner wall of the holes. The first metal hole 181 is electrically connected to the ground electrode 16, the second inductor 22, the third inductance part 231, and the fourth inductance part 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 inductance part 211, the second inductance part 212, the third inductance part 231, and the fourth inductance part 232, and the fourth metal hole 184 is electrically connected to the fourth inductor 24 and the second output electrode 172. By providing the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184, series-parallel connection among 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 is ensured.

The axial directions of the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184 are all the height direction of the base 1, and the first metal hole 181, the second metal hole 182, the third metal hole 183, and the fourth metal hole 184 are disposed at intervals. The diameter ranges of the first metal hole 181, the second metal hole 182, the third metal hole 183 and the fourth metal hole 184 are all 0.1mm-0.15mm, the space of the substrate 1 is fully utilized, and the miniaturization of the balun structure is facilitated.

A capacitor is further disposed in the substrate 1, one end of the capacitor is electrically connected to the first output electrode 171, and the other end of the capacitor is electrically connected to the second output electrode 172. A capacitor is connected in parallel between the first output electrode 171 and the second output electrode 172, so that a noise signal can be effectively filtered.

The capacitor comprises a first capacitor part 191 and a second capacitor part 192 which are arranged oppositely, the first capacitor part 191 and the second capacitor part 192 are arranged at intervals, the first capacitor part 191 and the first output electrode 171 are integrally formed, and the second capacitor part 192 and the second output electrode 172 are integrally formed.

The input port 11, the first output port 12, the second output port 13 and the grounding port 14 are all three-layer metal structures, each three-layer metal structure comprises a silver layer, a nickel layer and a tin layer, the silver layer is close to the base body 1, the tin layer is far away from the base body 1, and the nickel layer is located between the silver layer and the tin layer. The three-layer metal structure can ensure the welding reliability of the product.

The first inductance section 211, the second inductor 22, the second inductance section 212, the third inductance section 231, the fourth inductor 24, and the fourth inductance section 232 are each composed of a quarter-wavelength line. The wire diameters of the first inductance section 211, the second inductor 22, the second inductance section 212, the third inductance section 231, the fourth inductor 24, and the fourth inductance section 232 are 85 μm.

The substrate 1 is made of low-temperature co-fired ceramic powder, the sintering temperature is 860-900 ℃, the dielectric constant of the ceramic powder is 4.8-6.2, and the dielectric loss factor tan alpha is less than or equal to 0.005. The substrate 1 is made of low-temperature co-fired ceramic powder, the sintering temperature is 880 ℃, the dielectric constant of the ceramic powder is 5.0, and the dielectric loss factor tan alpha is 0.001. The base body 1 is a cuboid ceramic base body 1, the length of the ceramic base body 1 is 3.2mm, the width of the ceramic base body 1 is 1.6mm, and the height of the ceramic base body 1 is 0.9mm.

An embodiment of the present application provides a method for manufacturing a balun structure, and referring to fig. 16, the method for manufacturing a balun structure includes the steps of:

s101: a first diaphragm 31 is provided, and a first output electrode 171 and a first capacitor 191 are printed on the first diaphragm 31, see fig. 5.

S102: the second diaphragm 32 is stacked on the first diaphragm 31, a through hole is provided in the second diaphragm 32 at a position corresponding to the second metal hole 182, the through hole in the second diaphragm 32 is metalized, and the ground electrode 16, the second output electrode 172, and the second capacitor portion 192 are printed on the second diaphragm 32, as shown in fig. 6.

S103: a third film 33 is stacked on the second film 32, four through holes are provided in the third film 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, respectively, the through holes in the third film 33 are metalized, and the first inductance section 211 is printed on the third film 33, as shown in fig. 7.

S104: a fourth film 34 is stacked on the third film 33, three through holes are respectively formed in the fourth film 34 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 in the fourth film 34 are metalized, and the second inductor 22 is printed on the fourth film 34, as shown in fig. 8.

S105: a fifth diaphragm 35 is stacked on the fourth diaphragm 34, four through holes are formed in the fifth diaphragm 35 at positions corresponding to the first metal hole 181, the third metal hole 183, and the fourth metal hole 184, respectively, the through holes in the fifth diaphragm 35 are metalized, and the second inductance section 212 is printed on the fifth diaphragm 35, as shown in fig. 9.

S106: the sixth film 36 is stacked on the fifth film 35, three through holes are provided in the sixth film 36 at positions corresponding to the first metal hole 181, the third metal hole 183, and the fourth metal hole 184, respectively, the through holes in the sixth film 36 are metallized, and the third inductance part 231 is printed on the sixth film 36, as shown in fig. 10.

S107: a seventh diaphragm 37 is stacked on the sixth diaphragm 36, three through holes are respectively formed in 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 in the seventh diaphragm 37 are metalized, and the fourth inductor 24 is printed on the seventh diaphragm 37, as shown in fig. 11.

S108: an eighth diaphragm 38 is stacked on the seventh diaphragm 37, two through holes are provided in the eighth diaphragm 38 at positions corresponding to the first metal hole 181 and the third metal hole 183, respectively, the through holes in the eighth diaphragm 38 are metalized, and the fourth inductance section 232 is printed on the eighth diaphragm 38, as shown in fig. 12.

S109: a ninth film sheet is stacked on the eighth film sheet 38, and a mark is printed on the ninth film sheet.

The above description is only a preferred embodiment of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims (10)

1. A balun structure, comprising:

the external surface of the base body is provided with an input port, a first output port, a second output port and a grounding port;

the first inductor is arranged in the substrate, one end of the first inductor is electrically connected with the input port, the other end of the first inductor is electrically connected with the grounding port, the first inductor comprises a first inductance part and a second inductance part, the first inductance part and the second inductance part are arranged at intervals, and the first inductance part and the second inductance part are connected in parallel;

a second inductor disposed in the substrate and coupled to the first inductor, wherein one end of the second inductor is electrically connected to the ground port, and the other end of the second inductor is electrically connected to the first output port, and the second inductor is located between the first inductor part and the second inductor part;

the third inductor is arranged in the substrate, two ends of the third inductor are electrically connected with the grounding port, the third inductor comprises a third inductor part and a fourth inductor part, the third inductor part and the fourth inductor part are arranged at intervals, and the third inductor part and the fourth inductor part are connected in parallel;

and the fourth inductor is arranged in the substrate and coupled with the third inductor, one end of the fourth inductor is electrically connected with the input port, the other end of the fourth inductor is electrically connected with the second output port, and the fourth inductor is positioned between the third inductance part and the fourth inductance part.

2. A balun structure as claimed in claim 1, wherein said first inductor, said second inductor, said third inductor and said fourth inductor are all planar spiral inductors, and have the same winding direction;

the first inductance part, the second inductor, the second inductance part, the third inductance part, the fourth inductor and the fourth inductance part are sequentially arranged along the height direction of the base body.

3. A balun structure as claimed in claim 1, wherein a ground electrode, a first output electrode and a second output electrode are disposed inside the base body, 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, and the second output electrode is electrically connected to the second output port and the fourth inductor;

the first output electrode and the second output electrode are arranged at intervals, and the second output electrode and the grounding electrode are positioned on the same plane.

4. A balun structure as claimed in claim 3, wherein a first metal hole, a second metal hole, a third metal hole and a fourth metal hole are provided in the substrate, the first metal hole electrically connects the ground electrode, the second inductor, the third inductance portion and the fourth inductance portion, the second metal hole electrically connects the second inductor and the first output electrode, the third metal hole electrically connects the first inductance portion, the second inductance portion, the third inductance portion and the fourth inductance portion, and the fourth metal hole electrically connects 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 the height direction of the base body, and the first metal hole, the second metal hole, the third metal hole and the fourth metal hole are arranged at intervals.

5. A balun structure as claimed in claim 3, wherein a capacitor is further disposed in the substrate, one end of the capacitor is electrically connected to the first output electrode, and the other end of the capacitor is electrically connected to the second output electrode;

the capacitor comprises a first capacitor part and a second capacitor part which are opposite to each other, the first capacitor part and the second capacitor part are arranged at intervals, the first capacitor part and the first output electrode are integrally formed, and the second capacitor part and the second output electrode are integrally formed.

6. A balun structure as claimed in claim 3, wherein the material of the ground electrode, the first output electrode and the second output electrode is silver and the thickness of the ground electrode, the first output electrode and the second output electrode is in the range of 7-13 μm.

7. A balun structure as claimed in claim 4, wherein the first metal hole, the second metal hole, the third metal hole and the fourth metal hole each have a diameter in the range of 0.1mm to 0.15mm;

the first, second, third, fourth and fourth inductive portions are all comprised of quarter-wave lines;

the first inductance section, the second inductor, the second inductance section, the third inductance section, the fourth inductor, and the fourth inductance section have a wire diameter of 85 μm.

8. The balun structure of any one of claims 1-7, wherein the input port, the first output port, the second output port and the ground port are all three-layer metal structures comprising a silver layer, a nickel layer and a tin layer, the silver layer being proximate to the substrate, the tin layer being distal from the substrate, the nickel layer being between the silver layer and the tin layer.

9. A balun structure according to any one of claims 1 to 7, characterized in that the substrate is a ceramic substrate having a rectangular parallelepiped shape and a length of 3.2mm, a width of 1.6mm and a height of 0.9mm.

10. A balun structure as claimed in any one of claims 1-7, wherein the passband frequency of the balun structure is 3400-4700MHz and the insertion loss in the passband is ≦ 1.2dB;

the amplitude unbalance degree of the balun structure is less than or equal to 1.2dB, and the phase unbalance degree of the balun structure is less than or equal to 10 degrees.

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