CN110277618B - Transformer type balun - Google Patents
Transformer type balun Download PDFInfo
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- CN110277618B CN110277618B CN201910528119.9A CN201910528119A CN110277618B CN 110277618 B CN110277618 B CN 110277618B CN 201910528119 A CN201910528119 A CN 201910528119A CN 110277618 B CN110277618 B CN 110277618B
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- 239000000919 ceramic Substances 0.000 claims abstract description 76
- 230000008878 coupling Effects 0.000 claims abstract description 15
- 238000010168 coupling process Methods 0.000 claims abstract description 15
- 238000005859 coupling reaction Methods 0.000 claims abstract description 15
- 239000003822 epoxy resin Substances 0.000 claims description 44
- 229920000647 polyepoxide Polymers 0.000 claims description 44
- 238000006243 chemical reaction Methods 0.000 claims description 7
- 238000000605 extraction Methods 0.000 claims description 6
- 238000002955 isolation Methods 0.000 claims description 6
- 230000002708 enhancing effect Effects 0.000 claims description 4
- 238000004806 packaging method and process Methods 0.000 claims description 4
- 238000003466 welding Methods 0.000 claims description 3
- 238000005452 bending Methods 0.000 description 9
- 230000035939 shock Effects 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- 238000003780 insertion Methods 0.000 description 4
- 230000037431 insertion Effects 0.000 description 4
- 230000008054 signal transmission Effects 0.000 description 4
- 239000004593 Epoxy Substances 0.000 description 3
- JIYIUPFAJUGHNL-UHFFFAOYSA-N [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] Chemical group [O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[O--].[Mn++].[Mn++].[Mn++].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Fe+3].[Zn++].[Zn++] JIYIUPFAJUGHNL-UHFFFAOYSA-N 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000010354 integration Effects 0.000 description 2
- 238000004891 communication Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F17/04—Fixed inductances of the signal type with magnetic core
- H01F17/06—Fixed inductances of the signal type with magnetic core with core substantially closed in itself, e.g. toroid
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/28—Coils; Windings; Conductive connections
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01P—WAVEGUIDES; RESONATORS, LINES, OR OTHER DEVICES OF THE WAVEGUIDE TYPE
- H01P5/00—Coupling devices of the waveguide type
- H01P5/08—Coupling devices of the waveguide type for linking dissimilar lines or devices
- H01P5/10—Coupling devices of the waveguide type for linking dissimilar lines or devices for coupling balanced lines or devices with unbalanced lines or devices
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F17/00—Fixed inductances of the signal type
- H01F2017/0093—Common mode choke coil
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- Microelectronics & Electronic Packaging (AREA)
- Coils Or Transformers For Communication (AREA)
Abstract
The invention provides a transformer type balun, which comprises a base provided with a containing groove, a ceramic bottom plate covered on the base and a coupling circuit arranged on one surface of the ceramic bottom plate close to the base, wherein a first signal port and a second signal port are arranged on one surface of the ceramic bottom plate far away from the base; the part of the ceramic bottom plate, which is far away from the base and is outside the first signal port and the second signal port, is stuck with a grounding pad which is used for grounding and is connected with a grounding line. When the transformer type balun is used, the part of one surface of the ceramic base plate except the first signal port and the second signal port can be used as a whole end electrode to be grounded in a large area, so that the ground end electrode is prevented from being broken when being subjected to vibration or impact, and the capacity of resisting vibration and impact of the transformer type balun is improved.
Description
Technical Field
The invention belongs to the technical field of communication electronic elements, and particularly relates to a transformer balun.
Background
Balun (Balun, also known as a balanced feed converter or transmission line balancer) is a key component of balanced circuit layout for filters, microwave balanced mixers, frequency multipliers, push-pull amplifiers and antenna feed networks. The transformer balun for realizing balance-unbalance conversion through the high-frequency transformer has the advantages of wider frequency band, smaller volume and larger power, and is gradually and widely applied to various electronic devices. At present, the transformer type balun has poor vibration resistance and impact resistance, and a grounding end electrode is easy to generate bending short circuit or even break under the condition of vibration or impact, so that the transformer type balun has low stability and reliability in working, and the application of the transformer type balun on equipment with vibration or impact is limited.
Disclosure of Invention
The invention aims to provide a transformer type balun, which aims to solve the problems of poor vibration resistance and impact resistance of the transformer type balun in the prior art, and easy occurrence of bending short circuit and even breakage of a grounding terminal electrode when the grounding terminal electrode is subjected to vibration or impact.
In order to achieve the above purpose, the technical scheme adopted by the invention is to provide a transformer balun, which further comprises a base provided with a containing groove, and a ceramic bottom plate assembled on the end face of the base provided with one end of the containing groove, wherein a grounding circuit is arranged on one surface of the ceramic bottom plate close to the base, and a first signal port for signal input and two second signal ports for differential signal output are arranged on one surface of the ceramic bottom plate far away from the base; the coupling circuit comprises a common-mode inductor positioned in the accommodating groove, wherein the input end of the common-mode inductor is electrically connected with the first signal port, the two output ends of the common-mode inductor are respectively electrically connected with the two second signal ports, and the grounding end of the common-mode inductor is electrically connected with the grounding circuit; the ceramic base plate is characterized in that a grounding pad used for grounding is attached to the part, which is far away from the base, of the base plate outside the first signal port and the second signal ports, and the grounding pad is electrically connected with the grounding circuit.
Further, the coupling circuit further comprises a first circuit for connecting the input end of the common-mode inductor with the first signal port, a second circuit and a third circuit for respectively connecting the two output ends of the common-mode inductor with the two second signal ports, the first circuit, the second circuit, the third circuit and the grounding circuit are respectively printed on the ceramic base plate in a circuit printing mode, a first epoxy resin layer for packaging the first circuit, the second circuit, the third circuit and the grounding circuit on the ceramic base plate is arranged on the ceramic base plate, and the common-mode inductor is supported and fixed on the first epoxy resin layer.
Further, pins of the input end and/or the output end of the common-mode inductor are supported on the first epoxy resin layer, and a second epoxy resin layer for packaging and fixing the pins of the input end and/or the output end of the common-mode inductor on the first epoxy resin layer is arranged on the first epoxy resin layer.
Further, a third epoxy layer is provided on the second epoxy layer to encapsulate and fix the common mode inductor on the second epoxy layer.
Further, the transformer balun further comprises a first shielding wire used for connecting the common mode inductor and the first signal port, the first shielding wire comprises a first conductive wire core connected with the first signal port, a first shielding layer wrapped outside the first conductive wire core and a first insulating layer wrapped outside the first shielding layer, the first conductive wire core is connected with the input end of the common mode inductor, the first shielding layer is grounded, and the first insulating layer is fixed on the ceramic bottom plate.
Further, one end of the first conductive wire core, which is connected with the input end of the common mode inductor, is connected to the ceramic bottom plate in an electronic spot welding mode.
Further, an end of the first shielding layer, which is close to the first signal port, is provided with an extraction end, the extraction end is supported on the base, and the base is provided with a fourth epoxy resin layer for fixing the extraction end on the base.
Further, the transformer balun further comprises a resistor for enhancing balance degree of balance-unbalance conversion amplitude, the resistor comprises a first thick film resistor for signal isolation, a second thick film resistor and a third thick film resistor for grounding isolation, two ends of the first thick film resistor are respectively and electrically connected with two second signal ports, two ends of the second thick film resistor are respectively connected with one second signal port and a grounding line, and two ends of the third thick film resistor are respectively connected with the other second signal port and the grounding line; and the first thick film resistor, the second thick film resistor and the third thick film resistor are packaged through the first epoxy resin layer and are manufactured on the ceramic bottom plate in an integrated mode.
Further, a plurality of grounding pins for connecting with a grounding point are welded on the grounding pad, and each grounding pin is fixed on the ceramic bottom plate by adopting epoxy resin adhesion.
Further, the ceramic bottom plate is adhered and fixed on one end face of the base provided with the accommodating groove by adopting epoxy resin.
The transformer type balun provided by the invention has the beneficial effects that: compared with the prior art, the transformer balun provided by the invention has the advantages that the ceramic bottom plate is arranged at the position of the base corresponding to the notch, and the common-mode inductor element of the coupling circuit is integrally arranged on one surface of the ceramic bottom plate, which faces the accommodating groove of the base, so that the common-mode inductor is arranged in the accommodating groove. Meanwhile, a first signal port for signal input and a second signal port for differential signal output are arranged on the other surface of the ceramic base plate, and a grounding pad is attached to the part, outside the first signal port and the second signal port, of the ceramic base plate on the surface, away from the base plate, of the ceramic base plate, so that the weldability of the ceramic base plate is enhanced, and the connection of a grounding point and a common mode inductor element on the ceramic base plate is facilitated. When the transformer type balun is used, the other surface of the ceramic base plate except the first signal port and the second signal port can be used as a whole end electrode to conduct large-area grounding treatment, so that the grounding end electrode is prevented from being easily bent, short-circuited and even broken when being subjected to vibration or impact, and the capacity of vibration resistance and impact resistance of the transformer type balun is effectively improved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it being obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a transformer balun side view provided in an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a base of a transformer balun according to an embodiment of the present invention;
FIG. 3 is a schematic view of the structure of a transformer balun on one side of a ceramic substrate according to an embodiment of the present invention;
FIG. 4 is a schematic view of the structure of the other side of the ceramic base plate of the transformer balun according to the present invention;
fig. 5 is a schematic structural diagram of a transformer balun common-mode inductor according to an embodiment of the present invention.
Wherein, the first reference mark of each drawing in the figure:
1-a base; 11-a containing groove;
2-a ceramic base plate; 21-a first line; 22-a second line; 23-a third line; 24-a ground line; 25-
A ground pad; 26-a first signal port; 27-a second signal port;
a 3-common mode inductor; 31-manganese zinc ferrite core; a 32-coil;
4-a ground line; 41-a first conductive core; 42-a first shielding layer; 43-a first insulating layer;
5-a second shield wire; 51-a second conductive core; 52-a second shielding layer; 53-a second insulating layer;
a 6-resistor; 61-a first thick film resistor; 62-a second thick film resistor; 63-a third thick film resistor;
7-a third shielded wire; 71-a third shielding layer; 72-a third insulating layer;
8-fourth shielded wires; 81-a fourth shielding layer; 82-a fourth insulating layer; 9-feedback inductor.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the invention 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 for purposes of illustration only and are not intended to limit the scope of the invention.
It will be understood that when an element is referred to as being "connected 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.
Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature. In the description of the present invention, the meaning of "a plurality" is two or more, unless explicitly defined otherwise. The meaning of "a number" is one or more than one unless specifically defined otherwise.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communicated with the inside of two elements or the interaction relationship of the two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
Referring to fig. 1 to 5, a transformer balun according to an embodiment of the present invention will be described. The invention provides a transformer type balun, which comprises a coupling circuit for electromagnetic coupling, a base 1 provided with a containing groove 11, and a ceramic base plate 2 assembled on the end face of one end of the base 1 provided with the containing groove 11, wherein the coupling circuit is arranged on one surface of the ceramic base plate 2 close to the base 1, a grounding circuit 24 is arranged on one surface of the coupling circuit close to the base 1 and the ceramic base plate 2, and a first signal port 26 for signal input and two second signal ports 27 for differential signal output are arranged on one surface of the ceramic base plate 2 far from the base 1; the coupling circuit comprises a common-mode inductor 3 positioned in the accommodating groove 11, wherein the input end of the common-mode inductor 3 is electrically connected with the first signal port 26, the two output ends of the common-mode inductor 3 are respectively electrically connected with the two second signal ports 27, and the grounding end of the common-mode inductor 3 is electrically connected with the grounding line 24; the part of the surface of the ceramic base plate 2, which is far away from the base 1 and is beyond the first signal port 26 and the two second signal ports 27, is stuck with a grounding pad 25 for grounding, and the grounding pad 25 is electrically connected with the grounding line 24, so that the weldability of the ceramic base plate 2 is enhanced, the transformer type balun grounding area is increased, and the vibration resistance and shock resistance of the transformer type balun are improved.
Preferably, referring to fig. 5 together, as a specific implementation manner of the transformer balun provided by the embodiment of the present invention, the common-mode inductor 3 includes a manganese-zinc ferrite core 31 and two flat coils 32 wound on the manganese-zinc ferrite core 31, and the common-mode inductor 3 is manufactured by adopting the manganese-zinc ferrite core 31 with low loss, so that the transformer balun achieves the purpose of being applicable to low frequency band use, has the broadband characteristic (0.5 MHz-6 GHz) from low frequency to high frequency ultra-bandwidth application, realizes the application requirement that the transformer balun can work in a wider bandwidth and has low insertion loss and excellent amplitude balance, expands the variety of the transformer balun, saves the assembly space, meets the test requirement of GJB1661 and GJB360B, and achieves the military requirement. The transformer and other components and working principles of the common-mode inductor 3 are all implemented by using the prior art known to those skilled in the art, and are not described herein.
Compared with the prior art, the transformer balun provided by the invention has the advantages that the ceramic base plate 2 is arranged at the position of the base 1 corresponding to the notch, and the common mode inductor 3 of the coupling circuit is arranged on one surface of the ceramic base plate 2 facing the accommodating groove 11 of the base 1 in an integrated manner, so that the common mode inductor 3 is arranged in the accommodating groove 11. Meanwhile, a first signal port 26 for signal input and a second signal port 27 for differential signal output are arranged on the other surface of the ceramic base plate 2, and a grounding pad 25 is attached to the part, outside the first signal port 26 and the second signal port 27, of the ceramic base plate 2 on the surface, away from the base plate 1, so that the weldability of the ceramic base plate 2 is enhanced, and a grounding line is conveniently connected with the common mode inductor 3 element on the ceramic base plate 2. When in use, the other surface of the ceramic bottom plate 2 except the first signal port 26 and the second signal port 27 can be used as a whole end electrode to carry out large-area grounding treatment, so that the grounding end electrode is prevented from being easy to generate bending short circuit or even fracture when being subjected to vibration or impact, and the capacity of vibration resistance and impact resistance of the transformer type balun is effectively improved.
Further, as a specific implementation manner of the transformer balun provided by the embodiment of the present invention, the coupling circuit further includes a first circuit 21 connecting the input end of the common-mode inductor 3 with the first signal port 26, and a second circuit 22 and a third circuit 23 respectively connecting two output ends of the common-mode inductor 3 with two second signal ports 27, where the first circuit 21, the second circuit 22, the third circuit 23 and the ground circuit 24 are respectively printed on the ceramic substrate 2 by circuit printing, so as to reduce the volume of the transformer balun. The ceramic bottom plate 2 is provided with the first epoxy resin layer for packaging the first circuit 21, the second circuit 22, the third circuit 23 and the grounding circuit 24 on the ceramic bottom plate 2, and the first circuit 21, the second circuit 22, the third circuit 23 and the grounding circuit 24 are packaged on the ceramic bottom plate 2 through the first epoxy resin layer, so that the firmness of the first circuit 21, the second circuit 22, the third circuit 23 and the grounding circuit 24 on the ceramic bottom plate 2 is enhanced, and the first circuit 21, the second circuit 22, the third circuit 23 and the grounding circuit 24 are prevented from being easily bent, shorted or broken when being subjected to vibration or impact, thereby effectively improving the capacity of the transformer type balun for vibration resistance and impact resistance.
Further, as a specific implementation manner of the transformer balun provided by the embodiment of the invention, the pins of the input end and/or the output end of the common-mode inductor 3 are supported on the first epoxy resin layer, the first epoxy resin layer is provided with the second epoxy resin layer for encapsulating and fixing the pins of the input end and/or the output end of the common-mode inductor 3 on the first epoxy resin layer, and the common-mode inductor 3 is supported and fixed on the second epoxy resin layer, and the pins of the input end and/or the output end of the common-mode inductor 3 are encapsulated and fixed on the first epoxy resin layer through the second epoxy resin layer, so that the stability of the pins of the input end and/or the output end of the common-mode inductor 3 is enhanced, and the pins of the input end and/or the output end of the common-mode inductor 3 are prevented from being easy to generate bending short circuit or even fracture when being subjected to vibration or impact, thereby effectively improving the anti-vibration and anti-impact capability of the transformer type balun.
Further, as a specific implementation manner of the transformer balun provided by the embodiment of the invention, the second epoxy resin layer is provided with the third epoxy resin layer for encapsulating and fixing the common-mode inductor 3 on the second epoxy resin layer, so that the common-mode inductor 3 is prevented from being easily vibrated or oscillated to be damaged when being vibrated or impacted, the stability of the common-mode inductor 3 arranged on the ceramic base plate 2 is enhanced, and the vibration resistance and impact resistance of the transformer type balun are effectively improved.
Preferably, the part of the accommodating groove 11 outside the common-mode inductor 3 is filled with cured epoxy resin, so that the stability of electronic components such as the common-mode inductor 3 and the like in the accommodating groove 11 is further enhanced, shaking and loosening of the electronic components such as the common-mode inductor 3 and the like under the environment of strong vibration and violent impact are avoided, the stable reliability of the operation of the transformer type balun is affected, and the transformer type balun is convenient to integrate with other circuit elements.
Further, referring to fig. 3, as a specific implementation of the transformer balun provided in the embodiment of the present invention, the transformer balun further includes a first shielding wire 4 for connecting the inductor and the first signal port 26, where the first shielding wire 4 includes a first conductive wire core 41 connected to the first signal input port 7, a first shielding layer 42 wrapped around the first conductive wire core 41, and a first insulating layer 43 wrapped around the first shielding layer 42, the first conductive wire core 41 is connected to the input end of the common-mode inductor 3, the first shielding layer 42 is grounded, and the first insulating layer 43 is fixed on the ceramic base plate 2.
In this embodiment, the first insulating layer 43 of the first shielding wire 4 is fixed on the ceramic base plate 2, so as to reduce the line-to-line capacitance between the first shielding wire 4 and the ceramic base plate 2, so as to improve the vibration and shock resistance of the transformer type balun, and enable the transformer type balun to work stably and reliably on the equipment with vibration and shock without damage. And, adopt first shielded wire 4 as the signal transmission line of common mode inductor 3, effectively avoid first conductive wire core 41 inside first shielded wire 4 to produce induced current and form the interference to the transmission signal to improve transformer formula balun balance-unbalance conversion's steady performance, make transformer formula balun have very superior in-band range, phase balance degree. Meanwhile, the first shielding wire 4 is used as a signal transmission wire of the input end of the common mode inductor 3, so that external electromagnetic interference and radio frequency interference can be effectively prevented from entering the first shielding wire 4 to increase loss of transmission signals, and the signal transmitted on the first conductive wire core 41 can be effectively prevented from being radiated to cause interference, thereby effectively reducing loss of transmission signals and enabling the transformer to have lower insertion loss.
Preferably, one end of the first conductive wire core 41 of the first shielding wire 4, which is used for connecting with the input end of the common mode inductor 3, is connected to the ceramic base plate 2 in an electronic spot welding mode, so that the bending deformation, even the breakage and the wire falling off of the first conductive wire core 41 of the first shielding wire 4 are prevented while the bending deformation, even the breaking and the wire falling off of the first conductive wire core 41 of the first shielding wire 4 are improved, and meanwhile, the line-to-line capacitance between the first conductive wire core 41 and the ceramic base plate 2 is reduced, so that the amplitude of the transformer balun balance-unbalance conversion is optimized, and the amplitude balance of the transformer balun balance-unbalance conversion is enhanced.
Preferably, one end of the first shielding layer 42 near the first signal port 26 is provided with a lead-out end, the lead-out end is supported on the base 1, and the base 1 is provided with a fourth epoxy resin layer for fixing the lead-out end on the base 1, so that the lead-out end of the first shielding layer 42 of the first shielding wire 4 is prevented from bending deformation or even breaking when being subjected to vibration or impact, and the vibration resistance and impact resistance of the transformer type balun are improved.
Further, referring to fig. 3 together, as a specific implementation of the balun provided by the embodiment of the present invention, further referring to fig. 1 together, as a specific implementation of the balun provided by the embodiment of the present invention, the balun further includes a second shielding wire 5 for connecting the common-mode inductor 2 to the two second signal ports 27 respectively, the second shielding wire 5 includes two second conductive wire cores 51 connected to the two second signal ports 27 respectively, a second shielding layer 52 wrapped around the two second conductive wire cores 51, and a second insulating layer 53 wrapped around the second shielding layer 52, and the two second conductive wire cores 51 are connected to the two output ends of the common-mode inductor 2 respectively, the second shielding layer 52 is grounded, and the second insulating layer 53 is fixed on the substrate 1.
In this embodiment, the second shielding wire 5 is used to replace the enameled wire used for connecting the common-mode inductor 2 with the signal output end, and the second shielding wire 5 is used as the signal transmission wire of the output end of the common-mode inductor 2, so that the interference of the induced current generated by the second conductive wire core 51 inside the second shielding wire 5 on the transmission signal is effectively avoided, and the stability of balun transformer balance-unbalance conversion is improved, so that the balun transformer has very excellent in-band amplitude and phase balance. Meanwhile, the second shielding wire 5 is used as a signal transmission wire at the output end of the common mode inductor 2, so that the loss of a transmission signal can be effectively reduced, and the transformer has lower insertion loss.
Further, referring to fig. 3, as a specific implementation of the transformer balun provided by the embodiment of the present invention, the transformer balun further includes a resistor 6 for enhancing the balance degree of the balun amplitude, the resistor 6 includes a first thick film resistor 61 for signal isolation, and a second thick film resistor 62 and a third thick film resistor 63 for ground isolation, two ends of the first thick film resistor 61 are respectively electrically connected to two second signal ports 27, two ends of the second thick film resistor 62 are respectively connected to one second signal port 27 and a ground line 24, and two ends of the third thick film resistor 63 are respectively connected to the other second signal port 27 and the ground line 24; and the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63 are all encapsulated by the first epoxy resin layer and are integrally formed on the ceramic base plate 2.
In this embodiment, the resistor 6 comprises a first thick film resistor 61, a second thick film resistor 62 and a third thick film resistor 63 connected in series with each other, facilitating integration of the transformer type balun with other circuit elements. And the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63 are integrated on the substrate in a triangle arrangement mode, signals are isolated through the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63 are isolated from the ground, the amplitude of signals output by the second signal port 27 is enabled to be more stable, the excellent amplitude and the phase balance degree in the balun band of the transformer are enhanced, and the transformer has lower insertion loss.
In this embodiment, the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63 are integrally formed on the surface of the ceramic base plate 2 close to the base 1, so as to enhance the connection firmness of the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63, and prevent the stable reliability of the transformer balun from being affected by shaking and falling of the first thick film resistor 61, the second thick film resistor 62 and the third thick film resistor 63, and simultaneously reduce the volume of the transformer balun, thereby facilitating the integration of the transformer balun and other circuit elements and enabling the transformer balun to be applied to small-volume electronic equipment.
Preferably, a plurality of ground pins for connecting to a ground point are soldered on the ground pad 25 to conveniently connect the ground pad 25 to the ground point; the grounding pins are adhered and fixed on the ceramic bottom plate 2 by epoxy resin, so that the grounding pins are prevented from bending deformation or even breaking when being subjected to vibration and impact, and the vibration resistance and impact resistance of the transformer type balun are improved.
Preferably, the ceramic bottom plate 2 is fixed on one end surface of the base 1 provided with the notch of the accommodating groove 11 through epoxy resin adhesion, so that the connection firmness between the ceramic bottom plate 2 and the base 1 is enhanced, the vibration resistance and shock resistance of the transformer type balun are improved, and the transformer type balun is convenient to integrate with other circuit elements.
Preferably, the common-mode inductor 3 is encapsulated on one surface of the ceramic base plate 2 close to the base 1 through epoxy resin, so that the common-mode inductor 3, the ceramic base plate 2 and the base 1 form a whole, the vibration resistance and the shock resistance of the transformer type balun are improved, and the transformer type balun is convenient to integrate with other circuit elements.
Preferably, a plurality of ground pins for connecting to a ground point are soldered on the ground pad 9 to conveniently connect the ground pad 9 to the ground point; the grounding pins are adhered and fixed on the ceramic bottom plate 2 by epoxy resin, so that the grounding pins are prevented from bending deformation or even breaking when being subjected to vibration and impact, and the vibration resistance and impact resistance of the transformer type balun are improved.
Preferably, the ceramic bottom plate 2 is fixed on one end surface of the base 1 provided with the notch of the accommodating groove 11 through epoxy resin adhesion, so that the connection firmness between the ceramic bottom plate 2 and the base 1 is enhanced, the vibration resistance and shock resistance of the transformer type balun are improved, and the transformer type balun is convenient to integrate with other circuit elements.
Preferably, the common-mode inductor 3 is encapsulated on one surface of the ceramic base plate 2 close to the base 1 through epoxy resin, so that the common-mode inductor 3, the ceramic base plate 2 and the base 1 form a whole, the vibration resistance and the shock resistance of the transformer type balun are improved, and the transformer type balun is convenient to integrate with other circuit elements.
Further, referring to fig. 3 together, as a specific implementation manner of the balun transformer provided by the embodiment of the present invention, the balun transformer further includes a feedback inductor 9 for forming a signal feedback bypass, a third shielding wire 7 and a fourth shielding wire 8, the third shielding wire 7 includes a third conductive wire, a third shielding layer 71 wrapped around the third conductive wire, and a third insulating layer 72 wrapped around the third shielding layer 71, the third conductive wire is connected to an input end of the feedback inductor 9, the third shielding layer 71 is connected to a second signal port 27 and a ground line 24 through a second line 22, and the third insulating layer 72 is fixed on the substrate 1; the fourth shielding wire 8 comprises a fourth conductive wire, a fourth shielding layer 81 wrapped outside the fourth conductive wire and a fourth insulating layer 82 wrapped outside the fourth shielding layer 81, the fourth conductive wire is connected with the output end of the feedback inductor 9, the fourth shielding layer 81 is grounded, and the fourth insulating layer 82 is fixed on the substrate 1.
In this embodiment, the input signal is transmitted from the first signal port 26 to the common-mode inductor 2, and the input signal is distributed to the second signal ports 27 of the two output differential signals after being subjected to balun transformation by the common-mode inductor 2, so that the line-to-line capacitance of the feedback inductor 9 has a bypass effect on the ground terminal, and forms signal feedback, and the line-to-line capacitance of the feedback inductor 9 is prevented from forming interference, thereby further optimizing the balun transformer amplitude and enhancing the balun transformer amplitude balance.
The foregoing description of the preferred embodiments of the invention is not intended to be limiting, but rather is intended to cover all modifications, equivalents, and alternatives falling within the spirit and principles of the invention.
Claims (7)
1. A transformer balun comprising a coupling circuit for electromagnetic coupling, characterized in that: the transformer balun further comprises a base provided with a containing groove and a ceramic bottom plate assembled on the end face of the base provided with one end of the containing groove, a grounding circuit is arranged on one surface of the ceramic bottom plate close to the base, and a first signal port for signal input and two second signal ports for differential signal output are arranged on one surface of the ceramic bottom plate far away from the base; the coupling circuit comprises a common-mode inductor positioned in the accommodating groove, wherein the input end of the common-mode inductor is electrically connected with the first signal port, the two output ends of the common-mode inductor are respectively electrically connected with the two second signal ports, and the grounding end of the common-mode inductor is electrically connected with the grounding circuit; a grounding pad for grounding is attached to the part, outside the first signal port and the two second signal ports, of the surface, far away from the base, of the ceramic bottom plate, and the grounding pad is electrically connected with the grounding line;
the coupling circuit further comprises a first circuit for connecting the input end of the common-mode inductor with the first signal port, a second circuit and a third circuit for respectively connecting the two output ends of the common-mode inductor with the two second signal ports, wherein the first circuit, the second circuit, the third circuit and the grounding circuit are respectively printed on the ceramic base plate in a circuit printing mode, and a first epoxy resin layer for packaging the first circuit, the second circuit, the third circuit and the grounding circuit on the ceramic base plate is arranged on the ceramic base plate;
pins of the input end and/or the output end of the common-mode inductor are supported on the first epoxy resin layer, a second epoxy resin layer which encapsulates and fixes the pins of the input end and/or the output end of the common-mode inductor on the first epoxy resin layer is arranged on the first epoxy resin layer, and the common-mode inductor is supported and fixed on the second epoxy resin layer;
the transformer balun further comprises a first shielding wire used for connecting the common mode inductor and the first circuit, wherein the first shielding wire comprises a first conductive wire core connected with the first circuit, a first shielding layer wrapped outside the first conductive wire core and a first insulating layer wrapped outside the first shielding layer, the first conductive wire core is connected with the input end of the common mode inductor, the first shielding layer is grounded, and the first insulating layer is fixed on the ceramic bottom plate.
2. Transformer balun according to claim 1, characterized in that: and a third epoxy resin layer which encapsulates and fixes the common mode inductor on the second epoxy resin layer is arranged on the second epoxy resin layer.
3. Transformer balun according to claim 1, characterized in that: and one end of the first conductive wire core, which is connected with the input end of the common mode inductor, is connected to the ceramic bottom plate in an electronic spot welding mode.
4. Transformer balun according to claim 1, characterized in that: the first shielding layer is close to one end of the first signal port and is provided with an extraction end, the extraction end is supported on the base, and the base is provided with a fourth epoxy resin layer which is used for fixing the extraction end on the base.
5. Transformer balun according to claim 1, characterized in that: the transformer balun further comprises a resistor for enhancing balance degree of balance-unbalance conversion amplitude, the resistor comprises a first thick film resistor for signal isolation, a second thick film resistor and a third thick film resistor for grounding isolation, two ends of the first thick film resistor are respectively and electrically connected with two second signal ports, two ends of the second thick film resistor are respectively connected with one second signal port and a grounding circuit, and two ends of the third thick film resistor are respectively connected with the other second signal port and the grounding circuit; and the first thick film resistor, the second thick film resistor and the third thick film resistor are packaged through the first epoxy resin layer and are manufactured on the ceramic bottom plate in an integrated mode.
6. Transformer balun according to any one of claims 1-5, characterized in that: and a plurality of grounding pins used for being connected with a grounding point are welded on the grounding pad, and each grounding pin is fixed on the ceramic bottom plate by adopting epoxy resin adhesion.
7. Transformer balun according to any one of claims 1-5, characterized in that: the ceramic bottom plate is adhered and fixed on one end face of the base provided with the accommodating groove by adopting epoxy resin.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910528119.9A CN110277618B (en) | 2019-06-18 | 2019-06-18 | Transformer type balun |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910528119.9A CN110277618B (en) | 2019-06-18 | 2019-06-18 | Transformer type balun |
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| CN110277618A CN110277618A (en) | 2019-09-24 |
| CN110277618B true CN110277618B (en) | 2024-01-19 |
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| TW200515696A (en) * | 2003-10-20 | 2005-05-01 | Delta Electronics Inc | Balun built in multi-layer ceramic material layers |
| US7528676B2 (en) * | 2007-04-16 | 2009-05-05 | Tdk Corporation | Balun circuit suitable for integration with chip antenna |
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| US6278340B1 (en) * | 1999-05-11 | 2001-08-21 | Industrial Technology Research Institute | Miniaturized broadband balun transformer having broadside coupled lines |
| JP2005130376A (en) * | 2003-10-27 | 2005-05-19 | Sony Corp | Balun |
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| CN110277618A (en) | 2019-09-24 |
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