A four-way power splitter and method of manufacturing the same

Abstract

The application discloses a four-way power divider and a manufacturing method thereof, which comprises an LTCC integrated substrate, three ferrite cores, enameled wires, epoxy resin and a shell. The three ferrite cores are all wound with enameled wires to form three core coils, the three core coils are bonded on the LTCC integrated substrate through the epoxy resin, the leading ends of the enameled wires are connected to the LTCC integrated substrate, the shell is covered on the LTCC integrated substrate and is sealed by the epoxy resin, and the LTCC integrated substrate is integrated with resistors and capacitors of the four-way power divider. The resistors and the capacitors are integrated on the LTCC substrate, the product size is reduced, the operability of the product process is improved, the surface component welding is cancelled, and the component falling phenomenon in the secondary reflow soldering of the product is avoided. After the leading ends of the enameled wires are welded on the pads of the LTCC substrate, the solder points are subjected to high-temperature tin tinning treatment, the solder points are covered with tin, and the loose soldering of the solder points is prevented.

Description

Technical Field

[0001] This invention relates to a four-way power divider and its manufacturing method, belonging to the technical field of four-way power dividers. Background Technology

[0002] With increasingly stringent requirements for equipment reliability and environmental adaptability, there is a need for highly reliable, miniaturized, and fully sealed microwave devices to ensure equipment lifespan, reliability, and environmental adaptability. However, commercially available four-way power dividers of the same size cannot achieve full sealing due to circuit structure and size limitations. This poses a risk of cleaning fluid residue remaining inside the product during post-installation cleaning, potentially causing product failure. Furthermore, since conventional four-way power dividers are fully sealed, applying protective coatings to exposed microwave components after installation can negatively impact performance. The inability to apply protective coatings to fully sealed power dividers significantly reduces the overall moisture resistance and lifespan of the device. Summary of the Invention

[0003] The technical problem to be solved by this invention is to provide a four-way power divider and its manufacturing method, which solves the problems of miniaturization and full sealing of the four-way power divider; solves the problem of cleaning fluid residue inside the product during cleaning and three-proofing process after the whole machine is mounted; and solves the problem of not being able to achieve three-proofing. The invention provides a four-way power divider / combiner that can evenly divide one power signal into four power signals for output within a wide frequency range. The current product has small size, simple and easy processing technology, low insertion loss, high isolation, high quality, low VSWR, low amplitude imbalance, and low phase imbalance.

[0004] The technical solution adopted in this invention is as follows: a four-way power divider, comprising an LTCC integrated substrate, ferrite cores, enameled wire, epoxy resin, and a housing. Three ferrite cores are used, each wound with enameled wire to form three core coils. The three core coils are bonded to the LTCC integrated substrate with epoxy resin. The leads of the enameled wire are connected to the pads of the LTCC integrated substrate. The housing covers the LTCC integrated substrate and is sealed with epoxy resin. The LTCC integrated substrate integrates the resistors and capacitors of the four-way power divider.

[0005] Furthermore, the leads of the enameled wires are soldered to the pads of the LTCC integrated substrate using high-temperature tin.

[0006] Furthermore, the aforementioned four-way power divider also includes a four-way power divider circuit structure, which includes a first inductor group, a second inductor group, a third inductor group, and a fourth inductor group. The first inductor group is connected to the signal input terminal, the tap of the second inductor group is connected to the tap of the first inductor group, a first resistor is connected in parallel across the two ends of the second inductor group, and the two ends are respectively connected to the taps of the third inductor group and the tap of the fourth inductor group. A second resistor and a third resistor are connected in parallel across the output terminals of the third inductor group and the fourth inductor group, respectively. A first capacitor and a second capacitor are also connected in parallel across the taps of the third inductor group and the tap of the fourth inductor group. The two ends of the second resistor and the third resistor are the four-way signal output terminals.

[0007] Furthermore, the first inductor group includes two inductors connected in series, with one end of the series connection serving as the signal input terminal and the other end grounded. The tap between two adjacent inductors is connected to the tap of the second inductor group.

[0008] Furthermore, the aforementioned second inductor group comprises two inductors connected in series.

[0009] Furthermore, both the third and fourth inductor groups mentioned above include two inductors connected in series.

[0010] Furthermore, the first, second, third, and fourth inductor groups mentioned above are wound using a double-wire method.

[0011] A method for manufacturing a four-way power divider includes: using LTCC (Low Temperature Co-fired Ceramic) technology and process, integrating two capacitors and three resistors in the circuit onto a substrate; designing pads on the LTCC integrated substrate to connect the input and output of the four-way power divider; attaching a ferrite core to the LTCC integrated substrate with epoxy resin and curing it at high temperature; winding double-wire twisted enameled wire around the ferrite core and soldering the leads of the enameled wire to the pads on the LTCC integrated substrate using an electronic spot welder; soldering the solder joints with high-temperature tin; and sealing the power divider with a shell and epoxy resin.

[0012] Furthermore, the sealing method described above is as follows: The sealing process for the four-way power divider involves completely sealing one end of the housing opening onto the substrate using epoxy resin. The epoxy resin needs to be applied in two stages: First, according to the dimensions of the housing frame, epoxy resin is applied to the substrate using a dispensing method, leaving a 2-3mm vent hole. Then, the housing is assembled onto the substrate, and epoxy resin is used again to seal around the housing, leaving the vent hole unsealed. High temperature is then used for complete curing. The first processing completes the encapsulation of the product with the vent hole. Second: The encapsulated product with the vent hole from the first processing is placed on a heating table and heated for at least 10 minutes to expel all the air inside the housing until the air inside the housing no longer expands thermally. Once the air inside the housing reaches thermal equilibrium, epoxy resin is used to seal the vent hole. The product continues to be placed on the heating table for epoxy resin curing, obtaining the final encapsulated product. The temperature of the heating table is the epoxy resin curing temperature.

[0013] The beneficial effects of this invention are as follows: This invention integrates three resistors and two capacitors on an LTCC substrate, reducing product size and improving the operability of the product process. It eliminates surface component soldering, avoiding component detachment during secondary reflow soldering. After the enameled wire leads are soldered on the pads of the LTCC substrate, the solder joints are tinned with high-temperature tin to prevent cold solder joints from falling off. After optimizing the circuit structure, the surface space of the substrate is freed up, enabling the four-way power divider to be fully sealed. Attached Figure Description

[0014] Figure 1 This is a top view schematic diagram of the pad arrangement structure of an LTCC integrated substrate;

[0015] Figure 2 This is a schematic diagram of the pin arrangement structure of an LTCC integrated substrate viewed from below;

[0016] Figure 3 This is a top view of the four-way power divider after removing the outer casing;

[0017] Figure 4 This is a top view of the four-way power divider.

[0018] Figure 5 This is a front view schematic diagram of the four-way power divider;

[0019] Figure 6 This is a schematic diagram of the existing four-way power divider circuit structure;

[0020] Figure 7 This is a schematic diagram of the four-way power divider circuit structure of the present invention;

[0021] Figure 8This is a schematic diagram of the four-way power divider structure after the first sealing process;

[0022] Figure 9 This is a schematic diagram of the four-way power divider structure after the second sealing of the exhaust port;

[0023] Figure 10 This is a schematic diagram of the structure of the four-way power divider placed on the heating platform after the exhaust port is blocked. Detailed Implementation

[0024] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1: As Figure 1-5 As shown, a four-way power divider includes an LTCC integrated substrate 1, ferrite cores 2, enameled wire 3, epoxy resin 4, and a housing 5. Three ferrite cores 2 are used, each wound with enameled wire 3 to form three core coils. The three core coils are bonded to the LTCC integrated substrate 1 via epoxy resin 4. The leads of the enameled wire 3 are connected to the LTCC integrated substrate 1. The housing 5 covers the LTCC integrated substrate 1 and is sealed with epoxy resin 4. The LTCC integrated substrate 1 integrates three resistors and two capacitors for the four-way power divider. The leads of the enameled wire are soldered to pads 7 on the LTCC integrated substrate 1 using high-temperature solder 6.

[0026] Three resistors and two capacitors are integrated onto the LTCC integrated substrate, reducing the product size to less than 8mm and 7mm in length and width, respectively. The length and width of the LTCC integrated substrate are more than 2mm larger than the shell size to ensure the product's sealing after packaging.

[0027] Reference Figure 1-2 Description of pinout and pads on LTCC integrated circuit board:

[0028] 1. Resistance between C1 and C2 pads: 100Ω;

[0029] 2. Resistance between pads J1 and J2: 150Ω;

[0030] 3. Resistance between pads F1 and F2: 150Ω;

[0031] 4. The capacitance between pads D and A2 is 4.7pF; the capacitance between pad E and A2 is 4.7pF.

[0032] 5. Pad A2 is electrically connected to pads 1, 2, 4, 5, and 8 on the bottom surface (large area common ground);

[0033] 6. Pads B1 and B2 are conductive;

[0034] 7. Pads A1 and 3 are conductive;

[0035] 8. F1 is connected to pad 10; F2 is connected to pad 9; J1 is connected to pad 7; J2 is connected to pad 6.

[0036] 9. C1 is conductive to pad E; C2 is conductive to pad D;

[0037] 10. Substrate thickness: 0.8mm;

[0038] 11. Porcelain body color: white;

[0039] 12. Electroplating with nickel and gold;

[0040] 13. The stress pins on the bottom pad of the LTCC are brazed.

[0041] This invention can be widely used in radio frequency circuits and has high reliability and safety.

[0042] This invention fulfills the function of power distribution and power combining in radio frequency circuits. When power distribution or power combining is required in radio frequency circuits, this product can achieve low-loss transmission.

[0043] Four-way power dividers are widely used in various radio frequency circuits to divide the energy of one input signal into four outputs of equal energy, or to combine the energy of four signals into one output.

[0044] Example 2: A four-way power divider also includes a four-way power divider circuit structure, such as... Figure 7 As shown, the circuit structure includes a first inductor group, a second inductor group, a third inductor group, and a fourth inductor group. The first inductor group is connected to the signal input terminal A. The tap of the second inductor group is connected to the tap of the first inductor group. A first resistor R1 is connected in parallel across the two ends of the second inductor group, and its two ends are respectively connected to the taps of the third inductor group and the fourth inductor group. A second resistor R2 and a third resistor R3 are connected in parallel across the output terminals of the third and fourth inductor groups, respectively. A first capacitor C is also connected in parallel across the taps of the third and fourth inductor groups. 1. The two ends of the second capacitor C2, the second resistor R2, and the third resistor R3 are four signal output terminals (A1, A2, A3, and A4); the first inductor group consists of two inductors connected in series, one end of which is the signal input terminal and the other end is grounded, and the tap between two adjacent inductors is connected to the tap of the second inductor group; the second inductor group consists of two inductors connected in series; the third and fourth inductor groups each consist of two inductors connected in series, and the first, second, third, and fourth inductor groups are wound in a double-wire manner.

[0045] The optimized circuit in this application has one less capacitor at the input terminal than the conventional circuit. Figure 6To reduce high-frequency coupling losses in existing power divider circuit structures, a direct output method is adopted for the second-stage output to minimize losses. Conventional circuits use a single enameled wire for the input and output windings; the optimized circuit uses a dual-wire winding for both, altering the transmission impedance and optimizing matching. This lowers the VSWR in the optimized circuit diagram, significantly reducing manufacturing costs, simplifying product manufacturing, and shrinking the product size. This allows the four-way power divider to achieve full sealing, reduces the capacitor in the first-stage input, and reduces the coil in the second-stage output (the magnetic core is nearly half the size; the previous circuit used a double-hole core, the improved one uses a single-hole core). The overall size of the four-way power divider is smaller, making miniaturization easier and reducing weight. With fewer second-stage circuits and a smaller magnetic core, the transmission line symmetry of the four outputs is improved, resulting in less transmission line difference, and better amplitude and phase balance.

[0046] In summary, the improved four-way power divider is applicable to various RF circuits and features low insertion loss, small amplitude imbalance, small phase imbalance, and low VSWR; it also boasts good electrical performance stability, light weight, small size, and high temperature resistance.

[0047] Example 3: A method for manufacturing a four-way power divider, comprising: using LTCC low-temperature co-fired ceramic technology and process, integrating two capacitors and three resistors in the circuit onto a substrate, and designing pads on the LTCC integrated substrate 1 to connect the input and output of the four-way power divider; attaching the ferrite core 2 to the LTCC integrated substrate 1 with epoxy resin 4 and curing it at high temperature; winding the double-wire twisted enameled wire 3 onto the ferrite core 2 and soldering the lead-out end of the enameled wire to the pads on the LTCC integrated substrate 1 using an electronic spot welder; soldering the solder joints with high-temperature tin; and sealing the power divider with a housing 5 and epoxy resin 4. The epoxy resin 4 is a single component that requires high-temperature curing.

[0048] The sealing method for the four-way power divider is as follows: The length and width dimensions of the LTCC integrated substrate 1 are larger than those of the housing 5. Epoxy resin 4 is used to completely seal one end of the opening of the housing 1 onto the substrate 1. The epoxy resin 4 used for sealing needs to be applied in two stages: First, according to the outer frame dimensions of the housing 5, epoxy resin 4 is applied to the substrate 1 by dispensing, leaving a 2-3mm vent hole 8. Then, the housing 5 is assembled onto the substrate 1, and epoxy resin 4 is used again to seal around the housing 5. The vent hole 8 needs to be left unsealed. Then, high temperature is used for complete curing. The first processing completes the encapsulated product with the reserved vent hole. Second: The encapsulated product with the reserved vent hole after the first processing is placed on a heating table and heated for more than 10 minutes (the heating temperature can be adjusted according to the product volume). Heating causes all the air inside the housing to be expelled until the air inside the housing will not expand thermally. When the air inside the housing reaches thermal equilibrium, epoxy resin is used to seal the vent hole. The product continues to be placed on the heating table 9 for epoxy resin curing to obtain the final encapsulated product. The temperature of the heating table 9 is the epoxy resin curing temperature.

[0049] The outer shell 5 and the substrate 1 are made of waterproof and watertight materials; the epoxy resin 4 is a high-temperature curing, single-component epoxy resin with a shear strength of 15 N / mm. 2 The above specifications have a hardness of 86D or higher, an operating temperature range of -65℃ to 220℃, and a viscosity of 280-400 Pa·s.

[0050] This invention utilizes the principle of air thermal balance in the sealing process. The product is placed on a heating platform and heated until the air inside the shell expands to reach thermal equilibrium. Then, epoxy resin is used to completely seal the shell and the substrate, thus solving the problem of water sealing and waterproofing of the device.

[0051] This invention effectively solves the problem of water sealing and waterproofing of devices by sealing epoxy resin twice. The first sealing involves leaving vent holes, and the second sealing is performed after the internal and external temperatures have reached equilibrium.

[0052] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of protection of the claims.

Claims

1. A four-way power divider, characterized in that: The LTCC integrated substrate (1), ferrite core (2), enameled wire (3), epoxy resin (4) and housing (5) are included. Three ferrite cores (2) are used, each wound with enameled wire (3) to form three core coils. The three core coils are bonded to the LTCC integrated substrate (1) by epoxy resin (4). The lead end of the enameled wire (3) is connected to the LTCC integrated substrate (1). The housing (5) covers the pad (7) of the LTCC integrated substrate (1) and is sealed with epoxy resin (4). The LTCC integrated substrate (1) integrates three resistors and two capacitors of a four-way power divider. It also includes a four-way power divider circuit structure, which includes a first inductor group, a second inductor group, a third inductor group, and a fourth inductor group. The first inductor group is connected to the signal input terminal. The tap of the second inductor group is connected to the tap of the first inductor group. A first resistor is connected in parallel across the two ends of the second inductor group, and its two ends are respectively connected to the taps of the third inductor group and the fourth inductor group. A second resistor and a third resistor are connected in parallel across the output terminals of the third inductor group and the fourth inductor group, respectively. A first capacitor and a second capacitor are also connected in parallel across the taps of the third inductor group and the fourth inductor group. The two ends of the second resistor and the third resistor are the four-way signal output terminals.

2. A four-way power divider according to claim 1, characterized in that: The lead-out end of the enameled wire is soldered to the pad of the LTCC integrated substrate (1) with high-temperature tin (6).

3. A four-way power divider according to claim 1, characterized in that: The first inductor group consists of two inductors connected in series. One end of the series connection is the signal input terminal, and the other end is grounded. The tap between two adjacent inductors is connected to the tap of the second inductor group.

4. A four-way power divider according to claim 1, characterized in that: The second inductor group consists of two inductors connected in series.

5. A four-way power divider according to claim 1, characterized in that: Both the third and fourth inductor groups consist of two inductors connected in series.

6. A four-way power divider according to claim 1, characterized in that: The first, second, third, and fourth inductor groups are wound using a double-wire method.

7. A method for manufacturing a four-way power divider according to any one of claims 1-2, characterized in that: The method is as follows: using LTCC low temperature co-fired ceramic technology and process, two capacitors and three resistors in the circuit are integrated onto the substrate, and pads for connecting the input and output of the four-way power divider are designed on the LTCC integrated substrate (1). The ferrite core (2) is pasted onto the LTCC integrated substrate (1) with epoxy resin (4) and cured at high temperature. Then, the double-wire twisted enameled wire (3) is wound on the ferrite core (2) and the lead end of the enameled wire is soldered to the pad of the LTCC integrated substrate (1) with an electronic spot welding machine. The solder joints are soldered with high temperature tin. The four-way power divider is sealed with shell (5) and epoxy resin (4).

8. A method for manufacturing a four-way power divider according to claim 7, characterized in that: The sealing method for the four-way power divider is as follows: Epoxy resin is used to completely seal the opening of the housing onto the substrate. The epoxy resin sealing requires two applications: First, according to the housing frame dimensions, epoxy resin is applied to the substrate using a dispensing method, leaving a 2-3mm vent hole. Then, the housing is assembled onto the substrate, and epoxy resin is used again to seal the area around the housing, leaving the vent hole unsealed. High temperature is then used for complete curing. This first processing completes the encapsulated product with the vent hole. Second, the encapsulated product with the vent hole from the first processing is placed on a heating table and heated for at least 10 minutes to expel all internal air until the internal air no longer expands. Once thermal equilibrium is reached, epoxy resin is used to seal the vent hole. The product continues to be placed on the heating table for epoxy resin curing, obtaining the final encapsulated product. The heating table temperature is the epoxy resin curing temperature.

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