10MHz-678MHz small-size directional coupler

Abstract

The utility model discloses a 10MHz-678MHz small-size directional coupler, which comprises two layers of PCBs (printed circuit boards) and a metal shell, each layer of the PCBs is grounded in a large area, that is, the ground is laid in the space outside an element bonding pad and a wire of the PCB layer, the bottom layer of the PCBs is the complete ground, an inductor L1, an inductor L2, an inductor L3 and an inductor L4 are arranged on the PCBs, and the inductor L1, the inductor L2, the inductor L3 and the inductor L4 are arranged on the metal shell. The layout of the directional coupler in the PCB is bilaterally symmetrical; the inductor L1, the inductor L2, the inductor L3 and the inductor L4 share one double-hole magnetic core. A large number of grounding through holes are adopted in the PCB, the grounding effect is improved, and the directional couplers arranged on the PCB are arranged in a bilateral symmetry mode, so that stray capacitance and inductance generated by a left bonding pad and a right bonding pad are equal, and later product manufacturing is facilitated; and a double-hole magnetic core is adopted, so that the size of the product is reduced by 10 * 7.6 * 5.1 mm.

Description

Technical Field

[0001] The utility model relates to a 10MHz-678MHz small-size directional coupler, belonging to the technical field of electrically adjustable filters. Background Art

[0002] like Figure 5-8 The directional coupler shown includes a housing, a coil encapsulated in the housing, and pins arranged at the bottom of the housing. The pin definitions are shown in the following table.

[0003] Pin sequence illustrate 1 Main line input 2 land 3 Forward coupling end / reverse isolation end 4 land 5 Forward isolation terminal / reverse coupling terminal 6 land 7 Main line output 8 land

[0004] The existing Mini-Circuits SYDC-20-62HP+ directional coupler has a size of 12.7*9.65*6.35mm and an operating frequency of 10MHz to 540MHz. It is large in size, occupies space, and the operating frequency cannot reach 10MHz to 540MHz. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a 10MHz-678MHz small-size directional coupler to solve the problems existing in the above-mentioned prior art.

[0006] The technical scheme adopted by the utility model is: a 10MHz-678MHz small-size directional coupler, comprising a PCB circuit board and a metal shell, the PCB circuit board is provided with two layers, each layer of the PCB circuit board is grounded through a large area, that is, the space outside the component pads and the wiring of the PCB circuit board layer is paved with the ground, the bottom layer of the PCB circuit board is a complete ground, the inductor L1, the inductor L2, the inductor L3 and the inductor L4 are arranged on the PCB circuit board, the layout of the directional coupler in the PCB circuit board adopts bilateral symmetry; the 6 pins of the PCB adopt a half-hole design; the inductor L1, the inductor L2, the inductor L3 and the inductor L4 share a double-hole magnetic core.

[0007] Furthermore, the circuit of the above-mentioned directional coupler includes inductor L1, inductor L2, inductor L3 and inductor L4, one end of the inductor L1 is connected to the main line input end, and the other end is connected to the main line output end and one end of the inductor L3, the other end of the inductor L3 is connected to the ground end and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the inductor L4 and the forward isolation end or the reverse coupling end, and the other end of the inductor L4 is connected to the forward coupling end or the reverse isolation end.

[0008] Furthermore, the inductor L1 is 0.5T and 0.38mm, the inductor L2 is 9T and 0.15mm, the inductor L3 is 9T and 0.15mm, and the inductor L4 is 0.5T and 0.38mm.

[0009] The beneficial effects of the utility model are as follows: compared with the prior art, the small-size directional coupler of the utility model has a size of 10*7.6*5.1mm, which is smaller than the conventional size. A double-hole magnetic core is adopted. In the case of a small volume, the cross-sectional area of ​​the magnetic core is increased, and a larger magnetic flux can be accommodated to achieve a larger power capacity. The layout of the directional coupler in the PCB circuit board adopts left-right symmetry, so that the parasitic capacitance and inductance generated by the left and right pads are equal, which is convenient for the subsequent product manufacturing. The 6 pins of the PCB adopt a half-hole design to increase the firmness of the pad position. The directional coupler of the utility model is bidirectionally coupled, and the use of a double-hole magnetic core can make the bidirectional coupling curve flatter. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is the wiring schematic diagram of a small-size directional coupler from 10MHz to 678MHz;

[0011] Figure 2 It is a schematic diagram of the top layer layout of the PCB circuit board;

[0012] Figure 3 It is a schematic diagram of the bottom layer layout of the PCB circuit board;

[0013] Figure 4 This is a schematic diagram of the PCB test fixture board;

[0014] Figure 5 It is a top view structural diagram of a directional coupler;

[0015] Figure 6 is a schematic diagram of the front view structure of a directional coupler;

[0016] Figure 7 It is a left-side structural diagram of a directional coupler;

[0017] Figure 8 It is a schematic diagram of the structure of a directional coupler viewed from above;

[0018] Fig. 9 It is a schematic diagram of the double-hole magnetic core structure;

[0019] Fig.10 It is a schematic diagram of the cross section of a double-hole magnetic core;

[0020] Fig.11 It is a schematic diagram of the left view of the double-hole magnetic core;

[0021] Fig.12 It is a schematic diagram of the side view structure of a double-hole magnetic core. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0023] Example 1: Figure 1-12As shown, a 10MHz~678MHz small-size directional coupler includes a PCB circuit board 1 and a metal shell 2. The PCB circuit board 1 is provided with two layers. Each layer of the PCB circuit board 1 is grounded through a large area, that is, the space outside the component pads and routing of the PCB circuit board layer is paved with the ground. The bottom layer of the PCB circuit board is a complete ground. Inductors L1, L2, L3 and L4 are arranged on the PCB circuit board. The layout of the directional coupler in the PCB circuit board 1 adopts left-right symmetry; the 6 pins of the PCB adopt a half-hole design; the inductors L1, L2, L3 and L4 share a double-hole magnetic core. Two plug-ins 3 are provided on the upper and lower sides of the PCB circuit board 1, and the four plug-ins 3 are inserted into the U-shaped grooves 4 provided on the upper and lower sides of the PCB circuit board 1 and bent to the bottom of the PCB circuit board 1, and the metal shell 2 is locked on the PCB circuit board. The upper and lower sides of the metal shell covering one end of the PCB circuit board are provided with strip-shaped through holes 5 corresponding to the pads.

[0024] The double-hole magnetic core 6 used by the inductors L1, L2, L3 and L4 is as follows: Figure 9-12 As shown, the double-hole magnetic core 6 is provided with a coating 7 on the outside. The coating is made of epoxy resin, which has the functions of 1. insulation protection and 2. preventing the core from cutting the enameled wire and protecting the enameled wire.

[0025] Furthermore, the circuit of the above-mentioned directional coupler includes inductor L1, inductor L2, inductor L3 and inductor L4, one end of the inductor L1 is connected to the main line input end, and the other end is connected to the main line output end and one end of the inductor L3, the other end of the inductor L3 is connected to the ground end and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the inductor L4 and the forward isolation end or the reverse coupling end, and the other end of the inductor L4 is connected to the forward coupling end or the reverse isolation end.

[0026] Furthermore, the inductor L1 is 0.5T and 0.38mm, the inductor L2 is 9T and 0.15mm, the inductor L3 is 9T and 0.15mm, and the inductor L4 is 0.5T and 0.38mm.

[0027] Example 2: Figure 1-12 As shown, a method for manufacturing a 10MHz to 678MHz small-size directional coupler comprises the following steps:

[0028] Step 1, PCB circuit board layout: The PCB circuit board is set up with two layers, and each layer of the PCB circuit board is grounded through a large area, that is, the space outside the component pads and traces of the PCB circuit board layer is paved with the ground, and the bottom layer of the PCB circuit board is a complete ground. The PCB circuit board uses a large number of grounding through holes to increase the grounding effect. The layout of the directional coupler in the PCB circuit board adopts left-right symmetry, so that the parasitic capacitance and inductance generated by the left and right pads are equal, which is convenient for the later product manufacturing; the 6 pins of the PCB adopt a half-hole design to increase the firmness of the pad position;

[0029] Step 2: The manufacturing method comprises the following steps:

[0030] 2.1) After preparing the PCB circuit board and the double-hole magnetic core, use epoxy resin E107HF to evenly apply it on the bottom of the double-hole magnetic core, then place it in the middle area of ​​the PCB circuit board, and bake it in a 100℃ oven for 1 hour to allow the epoxy resin E107HF to completely fix the double-hole magnetic core;

[0031] 2.2) According to the design parameters of the circuit diagram, use the enameled wire of the corresponding wire diameter, wind the corresponding number of turns, and spot weld the 0.15mm enameled wire to the pin pad of the corresponding PCB circuit board through an electric welder, and then fix it with high-temperature lead-free tin wire LC_D0.8mm, and then weld the 0.38mm enameled wire with high-temperature lead-free tin LC_D0.8mm;

[0032] 2.3) Use Loctite 3609 red glue to fix the enameled wire on the semi-finished product;

[0033] 2.5) Use high temperature lead-free tin wire LC_D0.8mm to seal the metal shell;

[0034] 2.6) After capping, the product is tested and the electrical performance index is tested to form a data report. Then the product is marked, cleaned, inspected and packaged to form a finished product.

[0035] A 10MHz~678MHz small-size directional coupler is prepared, with a size of 10*7.6*5.1mm, which is smaller than the conventional size, and the operating frequency can cover 10MHz~678MHZ, which saves space for the user end and increases the operating frequency of the user end. A double-hole magnetic core is used to increase the cross-sectional area of ​​the magnetic core while being small in size, so that a larger magnetic flux can be accommodated and a larger power capacity can be achieved. The directional coupler of the utility model is bidirectionally coupled, and the use of a double-hole magnetic core can make the bidirectional coupling curve flatter.

[0036] Furthermore, the circuit of the 10MHz to 678MHz small-size directional coupler prepared above includes an inductor L1, an inductor L2, an inductor L3 and an inductor L4, one end of the inductor L1 is connected to the main line input end, and the other end is connected to the main line output end and one end of the inductor L3, the other end of the inductor L3 is connected to the ground end and one end of the inductor L2, the other end of the inductor L2 is connected to one end of the inductor L4 and the forward isolation end or the reverse coupling end, the other end of the inductor L4 is connected to the forward coupling end or the reverse isolation end, and the inductor L1 and the inductor L2 and the inductor L3 and the inductor L4 share a double-hole magnetic core.

[0037] Furthermore, the inductor L1 is 0.5T and 0.38mm, the inductor L2 is 9T and 0.15mm, the inductor L3 is 9T and 0.15mm, and the inductor L4 is 0.5T and 0.38mm.

[0038] The 10MHz-678MHz small-size directional coupler comprises a PCB circuit board 1 and a metal shell 2, on which the electrical components of the directional coupler (inductor L1, inductor L2, inductor L3 and inductor L4) are arranged, the PCB circuit board 1 and the metal shell 2 covering the PCB circuit board 1, two inserting pieces 3 are arranged on the upper and lower sides of the PCB circuit board 1, the four inserting pieces 3 are inserted into the U-shaped grooves 4 arranged on the upper and lower sides of the PCB circuit board 1 and bent to the bottom of the PCB circuit board 1, the metal shell 2 is locked on the PCB circuit board, and the upper and lower sides of the metal shell covering one end of the PCB circuit board are provided with strip-shaped through holes 5 at corresponding pads.

[0039] The double-hole magnetic core 6 used by the inductors L1, L2, L3 and L4 is as follows: Figure 9-12 As shown, a coating 7 is provided on the outside of the double-hole magnetic core 6. The coating is made of epoxy resin, which 1. has the function of insulation protection; 2. prevents the core from cutting the enameled wire and plays a role in protecting the enameled wire. By using a double-hole magnetic core, the product size becomes smaller: 10*7.6*5.1mm.

[0040] The core material is FQ800, and the properties are shown in Table 1 below.

[0041] Table 1

[0042]

[0043] The circuit performance parameters are shown in Table 2:

[0044] Table 2 Circuit performance parameters

[0045]

[0046] The existing principle of 10MHz~678MHz small size directional coupler is as follows Figure 1As shown, it has smaller size, wider operating frequency and better performance indicators.

[0047] like Fig.10 As shown, the test fixture is a PCB board, and a pad is provided on the PCB board. The directional coupler is connected to the pad, and a reliable and stable test of the directional coupler can be performed, and the data test is accurate. The pin is fixed by welding and tested. After the test is completed, the welding point is loosened by a welding gun or the like, and the pin will not be damaged. The grounding pin is directly welded to the pad using the test fixture, and there is no need to use the bottom of the product, thereby avoiding affecting the bottom of the product due to welding and grounding during the grounding pin test. The following problems in the prior art of using a connecting cable to connect to a directional coupler for testing are effectively solved:

[0048] 1) Too many wires are connected, which can easily lead to errors and poor test accuracy;

[0049] 2) There is a risk of tearing off the product pins.

[0050] In order to quickly locate the directional coupler, a limit indication frame is drawn in the middle of the PCB board. The limit indication frame is larger than the directional coupler. Multiple welding pads corresponding to the directional coupler pins are arranged on the left and right sides of the limit indication frame (a total of 8, 3 on the left and right, and 1 on the top and bottom). The limit indication frame can be used to quickly limit the directional coupler, and then the terminals can be quickly welded, thereby improving welding efficiency and testing efficiency.

[0051] In order to prevent the directional coupler from shaking during the welding process, two limit pins are symmetrically arranged on the front and back sides of the upper surface of the PCB board. The two limit pins are inserted into the upper and lower slots (semicircular notch holes) of the PCB board to limit the front and rear ends of the directional coupler. When in use, the directional coupler is quickly placed in the two limit pins and moved left and right to the corresponding welding pads of the terminals. Before welding, it can be quickly positioned to avoid shaking during welding, making welding more stable and reliable.

[0052] Principle of use of test tooling:

[0053] 1. When measuring insertion loss: connect pin 1 of the test fixture to the input port of the network analyzer, connect pin 7 of the test fixture to the input port of the network analyzer, and connect pins 3 and 5 of the test fixture to a 50 ohm load.

[0054] 2. When measuring forward coupling: connect pin 1 of the test fixture to the input port of the network analyzer, connect pin 3 of the test fixture to the input port of the network analyzer, and connect pins 5 and 7 of the test fixture to a 50 ohm load.

[0055] 3. When measuring forward isolation: connect pin 1 of the test fixture to the input port of the network analyzer, connect pin 5 of the test fixture to the input port of the network analyzer, and connect pins 3 and 7 of the test fixture to a 50 ohm load.

[0056] 4. When measuring reverse coupling: connect pin 7 of the test fixture to the input port of the network analyzer, connect pin 5 of the test fixture to the input port of the network analyzer, and connect pins 1 and 3 of the test fixture to a 50 ohm load.

[0057] 5. When measuring reverse isolation: connect pin 7 of the test tool to the input port of the network analyzer, connect pin 3 of the test tool to the input port of the network analyzer, and connect pins 1 and 5 of the test tool to a 50 ohm load.

[0058] Note: Directivity (forward) = forward isolation – forward coupling

[0059] Directivity (reverse) = reverse isolation – reverse coupling.

[0060] The above description is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present utility model, which should be included in the protection scope of the present utility model. Therefore, the protection scope of the present utility model should be based on the protection scope of the claims.

Claims

1. A 10MHz~678MHz small size directional coupler, characterized by: The invention comprises a PCB circuit board and a metal shell covering the PCB circuit board. The PCB circuit board is provided with two layers. Each layer of the PCB circuit board is grounded through a large area, that is, the space other than the component pads and the wiring of the PCB circuit board layer is paved with the ground. The bottom layer of the PCB circuit board is a complete ground. Inductors L1, L2, L3 and L4 are arranged on the PCB circuit board. The layout of the directional coupler in the PCB circuit board is bilaterally symmetrical; the 6 pins of the PCB adopt a half-hole design; the inductors L1, L2, L3 and L4 share a double-hole magnetic core.

2. A 10MHz~678MHz small-size directional coupler according to claim 1, characterized in that: The circuit of the directional coupler includes inductor L1, inductor L2, inductor L3 and inductor L4, one end of inductor L1 is connected to the main line input end, and the other end is connected to the main line output end and one end of inductor L3, the other end of inductor L3 is connected to the ground end and one end of inductor L2, the other end of inductor L2 is connected to one end of inductor L4 and the forward isolation end or the reverse coupling end, and the other end of inductor L4 is connected to the forward coupling end or the reverse isolation end.

3. A 10MHz~678MHz small-size directional coupler according to claim 2, characterized in that: Inductor L1 uses an inductor of 0.5T and 0.38mm, inductor L2 uses an inductor of 9T and 0.15mm, inductor L3 uses an inductor of 9T and 0.15mm, and inductor L4 uses an inductor of 0.5T and 0.38mm.

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