Small high-precision power divider based on three-layer PCB

Abstract

The invention discloses a small high-precision power divider based on a three-layer PCB, the power divider comprises a first conductive layer, a second conductive layer and a third conductive layer, the first conductive layer comprises a first circuit, and the first circuit is provided with a first input port and two first output ports; the second conducting layer is arranged on one side of the first conducting layer, the second conducting layer comprises a plurality of second circuits, each second circuit is provided with a second input port and two second output ports, and the second input ports are electrically connected with the first output ports; the third conducting layer is arranged on the side, away from the first conducting layer, of the second conducting layer, the third conducting layer comprises a plurality of third circuits, each third circuit is provided with a third input port and two third output ports, and the third input ports are electrically connected with the second output ports. According to the power divider, the plane size of the PCB in the power divider is greatly reduced, the plane size of the whole power divider is finally reduced, and the application range of the power divider is wider.

Description

Technical Field

[0001] The present application relates to the technical field of power dividers, and in particular to a small-sized high-precision power divider based on a three-layer PCB board. Background Art

[0002] A power divider is a device that divides one input signal into two or more equal or unequal outputs. It is usually an equal distribution of energy. According to the output, it can be divided into two, three, four, six, eight, twelve, etc. It can also be used as a combiner. It is often used in antennas and mobile communications in the field of radio frequency microwaves.

[0003] Traditional power dividers are mostly designed using a single-layer PCB board. Under this structure, since all circuits are laid out on the same plane, the distance between circuits is difficult to effectively reduce, resulting in a larger plane size of the entire power divider. Summary of the invention

[0004] The main purpose of this application is to provide a small high-precision power divider based on a three-layer PCB board, aiming to solve the problem that all circuits of a traditional power divider are arranged on the same plane, and the distance between them is difficult to effectively reduce, resulting in a larger plane size of the entire power divider.

[0005] To achieve the above-mentioned purpose, the present application provides a small high-precision power divider based on a three-layer PCB board, the power divider comprising a first conductive layer, a second conductive layer and a third conductive layer, the first conductive layer comprising a first circuit, the first circuit having a first input port and two first output ports; the second conductive layer is arranged on one side of the first conductive layer, the second conductive layer comprising a plurality of second circuits, each second circuit having a second input port and two second output ports, each second input port being electrically connected to each first output port in a one-to-one correspondence; the third conductive layer is arranged on a side of the second conductive layer away from the first conductive layer, the third conductive layer comprising a plurality of third circuits, each third circuit having a third input port and two third output ports, each third input port being electrically connected to each second output port in a one-to-one correspondence; wherein the orthographic projections of the first circuit and the plurality of second circuits on the third conductive layer at least partially intersect with the area where the plurality of third circuits are located.

[0006] Optionally, metallized vias are provided on the first conductive layer, the second conductive layer and the third conductive layer; the second input port is electrically connected to the first output port through the metallized vias, and the third input port is electrically connected to the second output port through the metallized vias; the area where the orthographic projection of the first circuit on the third conductive layer is located is the first area, the area where the orthographic projections of multiple second circuits on the third conductive layer are located is the second area, the area where multiple third circuits are located is the third area, the ratio of the overlapping area of ​​the first area, the second area and the third area to the area of ​​the third conductive layer is a, and 30%<a<60%.

[0007] Optionally, the third conductive layer has a first side edge and a second side edge that are opposite to each other in a first direction, and the first direction is the same as a width direction of the third conductive layer; the orthographic projections of the first input port and the first output port on the third conductive layer are respectively toward the first side edge and the second side edge; the orthographic projections of the second input port and the second output port on the third conductive layer are respectively toward the second side edge and the first side edge; the orthographic projections of the third input port and the third output port on the third conductive layer are respectively toward the first side edge and the second side edge.

[0008] Optionally, the first circuit includes two first microstrip lines and multiple first resistors, the two first microstrip lines are arranged relative to each other in the second direction and the two ends of the first microstrip lines are respectively connected to the first input port and the first output port, and the second direction is the same as the length direction of the first conductive layer; the multiple first resistors are arranged at intervals in the first direction and are all connected between the two first microstrip lines, and the first direction is the same as the width direction of the first conductive layer; the second circuit includes two second microstrip lines, the two second microstrip lines are arranged relative to each other in the second direction and the two ends of the second microstrip lines are respectively connected to the second input port and the second output port; the third circuit includes two third microstrip lines and multiple third resistors, the two third microstrip lines are arranged relative to each other in the second direction and the two ends of the third microstrip lines are respectively connected to the third input port and the third output port; the multiple third resistors are arranged at intervals in the first direction and are all connected between the two third microstrip lines.

[0009] Optionally, the two first microstrip lines are mirror images of each other; the first microstrip line includes a first horizontal segment, a second horizontal segment, a plurality of third horizontal segments, a plurality of first vertical segments and a second vertical segment, one end of the first horizontal segment is connected to the first input port, an extension direction of the first horizontal segment is perpendicular to the first direction, and the first direction is the same as the width direction of the first conductive layer; the second horizontal segment is arranged on a side of the first horizontal segment close to the first output port, and an extension direction of the second horizontal segment is perpendicular to the first direction; a plurality of third horizontal segments are arranged in parallel between the first horizontal segment and the second horizontal segment in the first direction, and an extension direction of the third horizontal segment is perpendicular to the first direction; a plurality of first vertical segments are connected in series to the first horizontal segment, the The second horizontal segment and the plurality of third horizontal segments, the extension direction of the first vertical segment is the same as the first direction, wherein the plurality of first vertical segments are divided into a connection segment one and a connection segment two, in the second direction, the connection segment one is located on the side of the connection segment two close to the first input port, the extension directions of the connection segments one are all coincident, and the extension directions of the connection segments two are all coincident; one end of the second vertical segment is electrically connected to the second horizontal segment, and the other end is electrically connected to the first output port, and the extension direction of the second vertical segment is the same as the first direction; wherein the two ends of each of the first resistors are respectively electrically connected to the corresponding connection segment one of the two first microstrip lines; the first microstrip line, the second microstrip line and the third microstrip line are arranged in proportion.

[0010] Optionally, a ground layer is provided on both the first conductive layer and the third conductive layer; wherein both the first conductive layer and the third conductive layer are electrically connected to the adjacent ground layer through the metallized vias.

[0011] Optionally, a plurality of first elements related to the input matching network are arranged on the first conductive layer; a plurality of second elements related to the output matching network are arranged on the third conductive layer; gaps are arranged on both the first conductive layer and the third conductive layer to separate the first elements from the second elements; wherein the gaps are filled with electromagnetic shielding material.

[0012] Optionally, the power divider further includes nine electromagnetic shielding covers, and the multiple electromagnetic shielding covers are respectively arranged at the first input port and each of the third output ports and are electrically connected to the corresponding ground layer.

[0013] Optionally, the thickness of the first conductive layer is the same as that of the third conductive layer and is a first thickness, the thickness of the second conductive layer is a second thickness, the ratio of the first thickness to the second thickness is a, and 0.4<a<0.6.

[0014] Optionally, the first conductive layer, the second conductive layer and the third conductive layer all use a substrate of the same material, the dielectric constant of the substrate is 4.2-4.6, and the loss tangent is 0.02; the thickness of the first conductive layer and the third conductive layer are both 0.18-0.22 mm; the thickness of the second conductive layer is 0.38-0.42 mm.

[0015] The embodiment of the present application proposes a small high-precision power divider based on a three-layer PCB board, in which the first conductive layer, the second conductive layer and the third conductive layer are stacked, and the orthographic projections of the first circuit and the second circuit on the third conductive layer at least partially intersect with the area where the third circuit is located, so that the circuits on the three conductive layers are also stacked. Compared with setting all circuits on a single-layer PCB board, the planar size of the PCB board is greatly reduced, and finally the planar size of the entire power divider is reduced, which facilitates the application of the power divider in electronic devices with strict requirements on the device volume (such as portable communication equipment, miniaturized radio frequency sensors, etc.), and has a wider range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of the overall structure of a small high-precision power divider based on a three-layer PCB provided in an embodiment of the present application; Figure 2 A schematic diagram of the structure of the first conductive layer provided in an embodiment of the present application; Figure 3 A schematic diagram of the structure of the second conductive layer provided in an embodiment of the present application; Figure 4 A schematic diagram of the structure of the third conductive layer provided in an embodiment of the present application; Figure 5 A schematic diagram of the combined structure of the first conductive layer, the second conductive layer and the third conductive layer provided in an embodiment of the present application; Figure 6 for Figure 5 A magnified view of the structure in the middle.

[0017] In the figure: 1, first conductive layer; 2, first circuit; 21, first horizontal segment; 22, second horizontal segment; 23, third horizontal segment; 24, first vertical segment; 25, second vertical segment; 3, second conductive layer; 4, second circuit; 5, third conductive layer; 6, third circuit.

[0018] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] In the present invention, unless otherwise clearly specified and limited, the terms "connection", "fixation", etc. should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0023] Reference Figure 1 to Figure 6 It should be understood that Figure 1 Only the third conductive layer 5 is separated out, and the first conductive layer 1 and the second conductive layer 3 are still in a combined state, wherein, Figure 2R in the figure refers to the first resistor of the present application. The embodiment of the present application provides a small high-precision power divider based on a three-layer PCB board. The power divider may include a first conductive layer 1, a second conductive layer 3 and a third conductive layer 5. The first conductive layer 1 may include a first circuit 2, and the first circuit 2 has a first input port and two first output ports; the second conductive layer 3 is arranged on one side of the first conductive layer 1, and the second conductive layer 3 may include a plurality of second circuits 4, each of the second circuits 4 has a second input port and two second output ports, and each second input port is electrically connected to each first output port in a one-to-one correspondence; the third conductive layer 5 is arranged on the side of the second conductive layer 3 away from the first conductive layer 1, and the third conductive layer 5 may include a plurality of third circuits 6, each of the third circuits 6 has a third input port and two third output ports, and each third input port is electrically connected to each second output port in a one-to-one correspondence; wherein the orthographic projections of the first circuit 2 and the plurality of second circuits 4 on the third conductive layer 5 at least partially intersect with the area where the plurality of third circuits 6 are located.

[0024] The embodiment of the present application proposes a small high-precision power divider based on a three-layer PCB board, in which the first conductive layer 1, the second conductive layer 3 and the third conductive layer 5 are stacked, and the orthographic projections of the first circuit 2 and the second circuit 4 on the third conductive layer 5 at least partially intersect with the area where the third circuit 6 is located, so that the circuits on the three conductive layers are also stacked. Compared with setting all circuits on a single-layer PCB board, the plane size of the PCB board is greatly reduced, and the plane size of the entire power divider is finally reduced, which is convenient for the power divider to be used in electronic devices with strict requirements on the device volume (such as portable communication devices, miniaturized radio frequency sensors, etc.), and the scope of application is wider; compared with the traditional single-layer PCB board power divider, the volume of the power divider of the present application can be reduced by more than 50% while meeting the same electrical performance requirements. This miniaturized power divider is more suitable for use in electronic devices with strict requirements on volume.

[0025] Furthermore, each of the above-mentioned circuits has an input port and two output ports, and the two output ports receive the same power distribution. In the present application, four third circuits 6 are arranged at the third conductive layer 5, with a total of eight third output ports. The eight third output ports all receive the same power distribution, and finally eight power divisions are realized, wherein four second circuits 4 are arranged at the second conductive layer 3.

[0026] Furthermore, if the first circuit 2 or the second circuit 4 or the third circuit 6 is replaced by a circuit having one input port and three output ports, the number of the final third output ports is twelve, thus achieving twelve-power division.

[0027] Of course, a fourth conductive layer, a fifth conductive layer and other structures may be further added to achieve more detailed power division, ensuring that the input port of the circuit on the current conductive layer corresponds to the output port of the circuit on the previous conductive layer one by one.

[0028] In addition, the orthographic projections of the first circuit 2 and the multiple second circuits 4 on the third conductive layer 5 at least partially intersect with the area where the multiple third circuits 6 are located, which includes three areas, namely the area where the orthographic projection of the first circuit 2 on the third conductive layer 5 is located, the area where the orthographic projections of the multiple second circuits 4 on the third conductive layer 5 are located, and the area where the multiple third circuits 6 are located. At least partially intersecting means that at least two of the three areas overlap.

[0029] Among them, taking the first circuit 2 as an example, the area where the orthographic projection of the first circuit 2 on the third conductive layer is located refers to the area enclosed by the orthographic projections of the components on the first circuit 2 on the third conductive layer recorded as the first projection; of course, the periphery of the first projection is not continuous and must have a concave part, and the above-mentioned area includes the area of ​​the concave part; for example, assuming that there is a V-shaped concave somewhere in the first projection, the area of ​​the concave part refers to the area enclosed by the line connecting the two vertices of the V-shape and the V-shape.

[0030] It should be understood that there should be an insulating layer between adjacent conductive layers. The most basic function of the insulating layer is to provide electrical isolation to ensure that there is no direct electrical connection between adjacent conductive layers, thereby avoiding the occurrence of short circuits.

[0031] The first input port is the signal input end of the power divider, and the third output port is the signal output end of the power divider. The first output port, the second input port, the second output port and the third input port are used for electrical connection between adjacent conductive layers to form a complete combiner circuit through the circuit structures on the three conductive layers.

[0032] In an exemplary embodiment, a plurality of metallized vias are provided on the first conductive layer 1, the second conductive layer 3, and the third conductive layer 5; the second input port is electrically connected to the first output port through the metallized vias, and the third input port is electrically connected to the second output port through the metallized vias; The area where the orthographic projection of the first circuit 2 on the third conductive layer 5 is located is the first area, the area where the orthographic projections of the plurality of second circuits 4 on the third conductive layer 5 are located is the second area, the area where the plurality of third circuits 6 are located is the third area, and the ratio of the overlapping areas of the first area, the second area, and the third area to the area of ​​the third conductive layer 5 is a, and 30%<a<60%.

[0033] Specifically, by using metallized vias, different conductive layers can be connected in the thickness direction of each conductive layer, effectively saving space for horizontal wiring, making the three conductive layers more compact, and further reducing the volume of the power divider.

[0034] It should be understood that the larger the value of a is, the larger the overlapping area of ​​the three regions is, the smaller the plane area of ​​each conductive layer is, and the smaller the overall size of the power divider is. The specific value of a can be 35%, 40%, 45%, 50% and 55%, etc. In a preferred embodiment, the value of a is 40%, so that the reasonable distance between the circuits on each conductive layer has little interference, and the overlapping area of ​​the three regions is large, so as to achieve high precision and miniaturization of the power divider.

[0035] Among them, when making metallized vias, vias are first made on each conductive layer through laser drilling operation to ensure that the diameter accuracy of the vias reaches ±0.02mm, and then the vias are metallized to ensure good electrical connection.

[0036] refer to Figure 1 In the exemplary embodiment, the length direction and width direction of the first conductive layer 1, the second conductive layer 3 and the third conductive layer 5 are respectively the same. The third conductive layer 5 has a first side and a second side that are arranged opposite to each other in a first direction, and the first direction is the same as the width direction of the third conductive layer 5; the orthographic projections of the first input port and the first output port on the third conductive layer 5 are respectively oriented toward the first side and the second side; the orthographic projections of the second input port and the second output port on the third conductive layer 5 are respectively oriented toward the second side and the first side; the orthographic projections of the third input port and the third output port on the third conductive layer 5 are respectively oriented toward the first side and the second side.

[0037] Specifically, Figure 1 As shown, the input ports and output ports of each circuit are arranged in the first direction, and the orientation of the first input port and the first output port is opposite to the orientation of the second input port and the second output port, and the orientation of the second input port and the second output port is opposite to the orientation of the third input port and the third output port. In this way, the intersection area of ​​the orthographic projection of the first circuit 2 and the second circuit 4 on the third conductive layer 5 and the area where the third circuit 6 is located reaches the maximum, so that the planar area of ​​each conductive layer is further reduced, so that the overall volume of the power divider is further reduced, wherein the planar area of ​​each conductive layer is the same.

[0038] refer to Figure 2 to Figure 4In an exemplary embodiment, the first circuit 2 may include two first microstrip lines and a plurality of first resistors, the two first microstrip lines are arranged relative to each other in the second direction and the two ends of the first microstrip lines are respectively connected to the first input port and the first output port, and the second direction is the same as the length direction of the first conductive layer 1; the plurality of first resistors are arranged at intervals in the first direction and are all connected between the two first microstrip lines, the first resistor is located on the side of the first conductive layer 1 away from the second conductive layer 3, and the first direction is the same as the width direction of the first conductive layer 1; the second circuit 4 may include two second microstrip lines, the two second microstrip lines are arranged relative to each other in the second direction and the two ends of the second microstrip lines are respectively connected to the second input port and the second output port; the third circuit 6 may include two third microstrip lines and a plurality of third resistors, the two third microstrip lines are arranged relative to each other in the second direction and the two ends of the third microstrip lines are respectively connected to the third input port and the third output port; the plurality of third resistors are arranged at intervals in the first direction and are all connected between the two third microstrip lines, and the third resistor is located on the side of the third conductive layer 5 away from the second conductive layer 3.

[0039] Specifically, the microstrip line structures in each circuit are similar. Here, only the first microstrip line in the first circuit 2 is used for illustration. There are two first microstrip lines and they are arranged opposite to each other in the second direction, so that the two output ports can obtain equal power distribution.

[0040] The first resistor is located on the side of the first conductive layer 1 away from the second conductive layer 3 , and the third resistor is located on the side of the third conductive layer 5 away from the second conductive layer 3 , so as to ensure that the first resistor or the third resistor will not affect the combination of the three conductive layers.

[0041] Furthermore, in terms of component selection, appropriate resistors and microstrip line components are selected according to the operating frequency and performance requirements of the power divider. For example, for high-frequency power dividers (such as GHz level), resistors with high Q values ​​(quality factors) are selected to reduce the loss of the components themselves. At the same time, the layout of these components on the three-layer PCB board should comprehensively consider factors such as electromagnetic interference, signal transmission path and space utilization. The placement direction of the resistor should avoid its magnetic field from having unnecessary effects on surrounding components. In this application, the first resistor and the third resistor are both strip-shaped, and the length direction is the same as the second direction.

[0042] In addition, in high-frequency applications (such as microwave power dividers), the parasitic parameters of resistors (equivalent inductance and equivalent capacitance) will have a significant impact on the performance of the power divider. For high-frequency power dividers, resistors with low parasitic parameters should be selected. For example, the parasitic inductance and capacitance of thin film resistors (such as metal film resistors) at high frequencies are relatively small. When the power divider operates in the GHz frequency band, metal film resistors can reduce signal reflection and scattering to ensure the accuracy of power distribution. However, wirewound resistors have a certain inductance due to their own winding structure, which may cause phase shift and energy loss of the signal at high frequencies, and are not suitable for high-frequency power dividers.

[0043] At the same time, the resistance value of the resistor should remain stable within the operating frequency range of the power divider. The resistance value of some resistors will change with the change of frequency, which will affect the performance of the power divider such as the power distribution ratio. For example, thick film resistors have good frequency stability within a certain frequency range. If the operating frequency span of the power divider is large, choosing thick film resistors can maintain relatively stable performance throughout the frequency band, avoiding resistance value fluctuations caused by frequency changes, which in turn affects the output characteristics of the power divider.

[0044] Of course, the resistors in the power divider need to be able to withstand the power passing through it without being damaged. If the power capacity of the resistor is insufficient, it may overheat or even burn out under high power, causing the power divider to malfunction. For high-power power dividers (such as the power dividers at the transmitter end of a base station), it is necessary to select resistors with large power capacity. For example, you can choose high-power wirewound resistors or specially made high-power ceramic resistors. Wirewound resistors can improve their power handling capacity by selecting suitable winding materials and structures, while ceramic resistors have good heat dissipation properties and can work stably in high-power environments.

[0045] It should be understood that resistors consume a certain amount of power in a power divider, and this power loss will reduce the overall efficiency of the power divider. Selecting low-resistance, low-power resistors can help reduce power loss. When designing a low-loss power divider, if a branch requires a small resistor to achieve a specific function (such as matching or attenuation), you should choose a resistor type with accurate resistance and low power consumption, such as a high-precision metal film resistor.

[0046] Furthermore, some functions of the power divider (such as accurate power distribution ratio) rely on the accurate values ​​of the components in the circuit. The higher the resistance accuracy of the resistor, the greater the possibility of the power divider to achieve accurate power distribution. For example, the power divider in some precision measuring instruments may need to use high-precision metal film resistors, whose resistance accuracy can reach ±0.1% or even higher. Such high-precision resistors can ensure that the power divider accurately distributes power according to the design requirements and improve the accuracy of the measurement.

[0047] Among them, the change of the resistance value of the resistor with temperature will affect the performance stability of the power divider. For power dividers that require high precision, resistors with small temperature coefficients should be selected. For example, some special metal film resistors have extremely low temperature coefficients. In an environment with large temperature changes, they can maintain a relatively stable resistance value, thereby ensuring that the power distribution accuracy of the power divider will not deviate significantly due to temperature changes.

[0048] It should be noted that in some power dividers with high signal quality requirements (such as power dividers for weak signal reception), the noise of the resistor will affect the signal-to-noise ratio. Resistors with low noise coefficients should be selected. Generally speaking, the noise of metal film resistors is relatively low. When designing a low-noise power divider, the metal film resistor is preferred to reduce the noise generated by the resistor itself and improve the quality of the power divider output signal.

[0049] In special cases, if the power divider has strict requirements on the volume (such as the power divider in portable devices), it is necessary to choose a smaller resistor. Surface mount resistors (SMD) have the advantage of small size and are suitable for the design of miniaturized power dividers. For example, SMD resistors with package specifications such as 0402 and 0603 can effectively reduce the overall size of the power divider while meeting the circuit function.

[0050] In addition, in some cost-sensitive power divider applications (such as power dividers in mass-produced civilian consumer electronics), the cost of resistors needs to be considered comprehensively. Thick film resistors are usually cheaper, and if the performance can meet the requirements, thick film resistors can be preferred to reduce the production cost of the power divider.

[0051] refer to Figure 2In an exemplary embodiment, the first microstrip line may include a first horizontal segment 21, a second horizontal segment 22, a plurality of third horizontal segments 23, a plurality of first vertical segments 24 and a second vertical segment 25, one end of the first horizontal segment 21 is connected to the first input port, an extension direction of the first horizontal segment 21 is perpendicular to the first direction, and the first direction is the same as the width direction of the first conductive layer 1; the second horizontal segment 22 is arranged on a side of the first horizontal segment 21 close to the first output port, and an extension direction of the second horizontal segment 22 is perpendicular to the first direction; a plurality of third horizontal segments 23 are arranged in parallel between the first horizontal segment 21 and the second horizontal segment 22 in the first direction, and an extension direction of the third horizontal segment 23 is perpendicular to the first direction; a plurality of first vertical segments 24 are connected in series with the first vertical segment 24; and a plurality of third horizontal segments 23 are connected in parallel with the first horizontal segment 21 and the second horizontal segment 22 in the first direction. A horizontal segment 21, a second horizontal segment 22 and a plurality of third horizontal segments 23, the extension direction of the first vertical segment 24 is the same as the first direction, wherein the plurality of first vertical segments 24 are divided into a connection segment 1 and a connection segment 2, in the second direction, the connection segment 1 is located on the side of the connection segment 2 close to the first input port, the extension directions of the connection segments 1 all coincide, and the extension directions of the connection segments 2 all coincide; one end of the second vertical segment 25 is electrically connected to the second horizontal segment 22, and the other end is electrically connected to a first output port, and the extension direction of the second vertical segment 25 is the same as the first direction; wherein the two ends of each first resistor are respectively electrically connected to the corresponding connection segment 1 of the two first microstrip lines; the first microstrip line, the second microstrip line and the third microstrip line are arranged in proportion.

[0052] Specifically, Figure 2 As shown, the first horizontal segment 21 is electrically connected to the first input port, there are seven third horizontal segments 23 and they are arranged in parallel between the first horizontal segment 21 and the second horizontal segment 22, so there are nine horizontal segments in total, and eight first vertical segments 24 can be arranged to connect the nine horizontal segments in series. Since the seven third horizontal segments 23 are arranged in parallel between the first horizontal segment 21 and the second horizontal segment, the eight first vertical segments 24 connect the nine horizontal segments in series, as shown in FIG. Figure 1 As shown, the extension directions of the eight first vertical segments 24 do not overlap. The eight first vertical segments 24 are divided into four connecting segments 1 and four connecting segments 2. The extension directions of the connecting segments 1 overlap, and the extension directions of the connecting segments 2 overlap. The connecting segment 1 is located on the side of the connecting segment 2 close to the first input port. One end of the second vertical segment 25 is electrically connected to a first output port, and the other end is electrically connected to the second horizontal segment 22.

[0053] It should be noted that a second microstrip line in the second circuit 4 and a third microstrip line in the third circuit 6 also have a first horizontal segment, a second horizontal segment, seven third horizontal segments, eight first vertical segments and a second vertical segment, and the specific structure is similar to the above content, which will not be repeated here.

[0054] Furthermore, in the first circuit 2, a first microstrip line has four connecting segments 1, so that two first microstrip lines have eight connecting segments 1, and the eight connecting segments 1 are arranged opposite to each other in pairs, so that four first resistors are respectively arranged between two opposite connecting segments 1, and the two ends of the first resistor are respectively electrically connected to the two connecting segments 1; in addition, the setting of the third resistor is similar to the first resistor, and in a third circuit 6, there are also eight connecting segments 1 and four third resistors, and the specific structure is similar to the above content, which will not be repeated here.

[0055] Among them, low-loss metal materials such as copper can be selected for microstrip lines. Copper has good conductivity and can reduce signal loss during transmission.

[0056] In an exemplary embodiment, a ground layer is disposed on both the first conductive layer 1 and the third conductive layer 5 ; wherein both the first conductive layer 1 and the third conductive layer 5 are electrically connected to adjacent ground layers through metallized vias.

[0057] Specifically, a grounding layer is provided on both the first conductive layer 1 and the second conductive layer 3, and the grounding layer is connected to the middle layer through a plurality of grounding metallized vias to form a complete grounding system. The spacing between adjacent grounding metallized vias and the size of each grounding metallized via are optimized according to the operating frequency and the size of the PCB board. For example, in a power divider with an operating frequency of 2.4 GHz, the diameter of the grounding metallized vias can be 0.3 mm and the spacing can be 2 mm.

[0058] Among them, the first microstrip line, the second microstrip line and the third microstrip line are arranged in proportion, that is, in structure, the first microstrip line, the second microstrip line and the third microstrip line are the same, but the length is different; that is, the width and thickness of each of the first microstrip line, the second microstrip line and the third microstrip line are the same.

[0059] In an exemplary embodiment, a plurality of first elements related to an input matching network are arranged on the first conductive layer 1; a plurality of second elements related to an output matching network are arranged on the third conductive layer 5; gaps are arranged on both the first conductive layer 1 and the third conductive layer 5 to separate the first elements from the second elements; wherein the gaps are filled with electromagnetic shielding material.

[0060] Specifically, taking the first conductive layer 1 as an example, an isolation zone, i.e., a gap, can be set between the first elements on the first conductive layer 1. The gap can be etched on the first conductive layer 1, and the width of the gap is between 0.4 mm and 0.6 mm, for example, it can be 0.48 mm, 0.50 mm, and 0.52 mm, etc. In a preferred embodiment of the present application, the gap width is 0.5 mm and an electromagnetic shielding material is filled in the gap to reduce electromagnetic crosstalk between the first elements.

[0061] It should be noted that the electromagnetic shielding material may be electromagnetic shielding paint. In addition, the gap setting on the third conductive layer 5 may be similar to the gap setting on the first conductive layer 1 , so as to reduce the electromagnetic crosstalk between the third elements.

[0062] Furthermore, each first element and each third element may be arranged according to the electromagnetic compatibility principle to reduce mutual electromagnetic interference.

[0063] In addition, in the design of the input matching network, the required resistance is calculated using RF circuit theory based on the input impedance and source impedance of the power divider. Then, it is optimized and adjusted using electromagnetic simulation software to ensure that the reflection coefficient of the input port is minimized within the operating frequency range.

[0064] In an exemplary embodiment, the power divider may further include a plurality of electromagnetic shielding covers, which are respectively disposed at the first input port and each of the third output ports and are electrically connected to the corresponding ground layer.

[0065] Specifically, the electromagnetic shielding cover at the first input port corresponds to the ground layer on the first conductive layer 1; the electromagnetic shielding cover at the third output port corresponds to the ground layer on the third conductive layer 5. The electromagnetic shielding cover can effectively prevent external electromagnetic interference from entering the power divider and prevent internal signals from leaking out.

[0066] Among them, in the present application, there is one first input port, there are eight third output ports, and nine electromagnetic shielding covers are provided.

[0067] In the exemplary embodiment, the thickness of the first conductive layer 1 is the same as that of the third conductive layer 5 and is a first thickness, the thickness of the second conductive layer 3 is a second thickness, the ratio of the first thickness to the second thickness is a, and 0.4<a<0.6.

[0068] In an exemplary embodiment, the first conductive layer 1, the second conductive layer 3 and the third conductive layer 5 all use a substrate of the same material, the dielectric constant of the substrate is 4.2-4.6, and the loss tangent is 0.02; the thickness of the first conductive layer 1 and the third conductive layer 5 are both 0.18-0.22 mm; the thickness of the second conductive layer 3 is 0.38-0.42 mm.

[0069] In the preferred embodiment, a is 0.5, that is, the ratio of the thickness of the first conductive layer 1 to the thickness of the second conductive layer 3 is 0.5, the thickness of the first conductive layer 1 is 0.2 mm, the thickness of the second conductive layer 3 is 0.4 mm, and the substrate is a FR-4 board with a dielectric constant of 4.4 and a loss tangent of 0.02.

[0070] When making a microstrip line, the width and thickness of the microstrip line can be calculated according to the following formula for calculating the characteristic impedance of the microstrip line.

[0071] = In( ) Where: Indicates characteristic impedance, unit: ohm; represents the dielectric constant; Indicates basic thickness, unit: mm; represents the width of the microstrip line, unit: millimeter; t represents the thickness of the microstrip line, unit: millimeter.

[0072] Among them, the characteristic impedance can be 50 ohms, so the specific values ​​of the microstrip line width and thickness that meet the characteristic impedance can be calculated, and then the microstrip line is manufactured according to the calculated values. The manufacturing plans of the first microstrip line, the second microstrip line and the third microstrip line are the same.

[0073] It should be noted that when performing calculations, there are two unknowns in the characteristic impedance calculation formula of the above microstrip line, namely w and t. Based on the above formula, the relationship between w and t can be obtained. Then, based on the common range of w, the corresponding range of t can be calculated, and the corresponding values ​​of w and t can be selected to make the microstrip line.

[0074] In addition, for The value of can have a deviation within 0.1 ohm. In other words, , When the value of meets this range, any of the multiple relationships between w and t calculated by substituting it into the above-mentioned formula for calculating the characteristic impedance of the microstrip line can be used.

[0075] The common range of w is different in different power divider applications. For small high-precision power dividers, the common microstrip line width range can be between 0.5mm and 1.5mm. Specifically, in lower frequency applications, such as the MHz band, the width may be more common in the range of 0.8mm to 1.2mm. As the frequency increases to the GHz band, the width may gradually decrease to 0.5mm to 1mm.

[0076] In addition, the thickness of the microstrip line should also be within the common range, usually between 0.03mm and 0.15mm. For example, in some medium and low frequency applications, the thickness may be around 0.05mm to 0.1mm. For high frequencies and strict requirements on parasitic parameters, the thickness may be closer to 0.03mm to 0.08mm.

[0077] Furthermore, the width and thickness of the microstrip line need to be screened. For example, a wider microstrip line can reduce resistance loss, but may increase parasitic capacitance and affect high-frequency performance; a thinner microstrip line can reduce parasitic parameters, but resistance loss may increase. These two factors need to be considered comprehensively to ensure that the signal has the minimum insertion loss and return loss when transmitted on the microstrip line. The insertion loss and return loss curves under different combinations can be analyzed through simulation software, and the width and thickness combination with both parameters being ideal within the operating frequency range can be selected.

[0078] In addition, for a specific operating frequency range, microstrip lines of different widths and thicknesses will have different frequency response characteristics. In high-frequency applications, a combination that can maintain a stable frequency response over the entire operating frequency range should be selected. For example, in a GHz band power divider, the variation of S parameters (scattering parameters) with frequency under different combinations can be observed through simulation, and a width and thickness combination with a relatively gentle variation of S parameters within the operating frequency range can be selected.

[0079] Furthermore, consider the layout and space limitations of the three conductive layers. The width and thickness of the microstrip line cannot be too large, so as not to take up too much space and affect the installation of other components. For example, if the layout of other components on the conductive layer is relatively compact, the width of the microstrip line may need to be selected in a smaller range, such as 0.5mm to 0.8mm, to ensure that there is enough space for other components. At the same time, the thickness should also be coordinated with the interlayer spacing of each conductive layer to avoid affecting the interlayer connection or the overall structural stability due to excessive thickness. If the interlayer spacing of each conductive layer is small, the microstrip line thickness may need to be selected as a thinner specification to better connect with the upper and lower conductive layers and reduce signal reflection and loss.

[0080] In addition, for power dividers that require high miniaturization, barium titanate ceramic material can be used as the substrate, which has a higher dielectric constant.

[0081] When installing components, select the corresponding resistor according to the design requirements, and use a high-precision placement machine to mount the components on the corresponding conductive layer. The placement accuracy of the placement machine is ±0.05mm. During the placement process, ensure that the pads of the components and the conductive layer are aligned, and the placement pressure and time must meet the welding requirements of the components. After that, the reflow soldering technology is used to solder the mounted components. The temperature curve of reflow soldering has been optimized, and the temperature of the preheating zone is increased from room temperature to 150°C, with a heating rate of 1.5°C / s; the temperature of the insulation zone is maintained at 150-180°C for 60s; the temperature of the reflow zone reaches 210-230°C for 30s; the cooling zone cools to room temperature at a rate of 2°C / s.

[0082] After welding is completed, a network analyzer is used to conduct a comprehensive performance test on the power divider. Test items include power distribution ratio, reflection coefficient of input and output ports, isolation between different output ports, etc. Based on the test results, the power divider is fine-tuned and optimized, such as adjusting the value or position of the components to ensure that the power divider achieves the best performance indicators.

[0083] Compared with the traditional power divider, the small high-precision power divider based on the three-layer PCB board in this application is provided with three conductive layers, which can more accurately layout components and design microstrip lines, and the accuracy of the power distribution ratio is significantly improved. For example, for a power divider with a designed power distribution ratio of 1:1, within the operating frequency range, the deviation of the actual power distribution ratio can be controlled within ±0.1dB, while the deviation of the traditional single-layer PCB board power divider may reach ±0.3dB.

[0084] In addition, the designed input and output matching network and the good connection between the components and the microstrip line greatly reduce the reflection coefficient of the power divider at the input and output ports. Within the operating frequency range, the reflection coefficient of the input and output ports can be controlled below -20dB. Compared with the traditional single-layer PCB power divider (the reflection coefficient may only reach about -15dB), the signal matching performance has been significantly improved, and the power transmission efficiency has been improved.

[0085] At the same time, perfect electromagnetic shielding (i.e. electromagnetic shielding cover) and isolation measures (i.e. adding electromagnetic shielding materials at the gaps) effectively reduce the electromagnetic crosstalk between components and the impact of external electromagnetic interference on the power divider. The isolation between different output ports of the power divider can reach more than -30dB, while the isolation of traditional single-layer PCB power dividers may only be around -20dB, which improves the performance of the power divider in multi-port signal processing.

[0086] The optimized small power divider in the present application can be used in the fields of communication technology, radar technology, satellite communication technology and Internet of Things technology. The application of the small power divider will be illustrated below.

[0087] In the field of communications, firstly, for 5G and future communication base stations, large-scale multi-input and multi-output technology requires a large number of antenna units. High-precision small power divider technology can be applied to the RF power distribution network of the base station. The power divider manufactured by this process can accurately distribute the transmission power to many antenna ports, and its miniaturization helps to reduce the volume and weight of the base station equipment. For example, in active antenna units, the application of power divider technology can achieve efficient and accurate power distribution, reduce signal transmission loss, and improve the communication coverage and signal transmission capacity of the base station. Second, in mobile devices such as smartphones and tablets, with the increasing demand for multi-band and multi-mode communications (such as 2G / 3G / 4G / 5G coexistence), accurate RF signal processing is required in a compact space. High-precision small power divider technology can be used to build RF front-end modules in these devices. For example, the signal from the power amplifier is accurately distributed to antennas of different frequency bands to support multi-band communications. Due to the limited internal space of mobile devices, the process of small power dividers can meet its size constraints while ensuring the accuracy of signal power distribution and improving communication quality.

[0088] In the field of radar technology, firstly, phased array radar systems require precise power distribution and control of transmit and receive signals. High-precision small power divider technology can be used to manufacture power dividers in T / R (transmit / receive) components in phased array radars. In phased array radars, each T / R component requires a power divider to accurately distribute transmit power to each antenna unit or combine the signals of receiving antenna units. The small power divider technology can meet the miniaturization requirements of T / R components while ensuring high precision of power distribution, thereby improving the beam pointing accuracy, resolution and detection capability of phased array radars. Secondly, automotive millimeter-wave radar plays a key role in autonomous driving and assisted driving systems, such as detecting obstacles and targets around vehicles. High-precision small power divider technology can be applied to the RF front end of millimeter-wave radars to accurately distribute RF signals to multiple antennas or processing channels. Due to the limited space inside the car, the power divider manufactured by the small power divider technology can meet the compact structural design requirements of millimeter-wave radars, and its high precision helps to improve the radar's measurement accuracy of target distance, speed and angle.

[0089] In the field of satellite communication technology, firstly, the receiving and transmitting systems of satellite ground stations also need power dividers to process RF signals. The high-precision small power divider process can be applied to the RF front end in ground station equipment to accurately distribute the received weak satellite signals to different processing units, or distribute the transmitted signals to multiple antenna units. The process of small power dividers helps to improve the integration of ground station equipment, reduce the size of equipment, and ensure the accuracy of power distribution, thereby improving the quality of satellite communications. Secondly, in satellite communication payloads (such as transponders), accurate power distribution of RF signals is required. The high-precision small power divider process can be used to manufacture power dividers in satellite payloads. The space and weight resources on satellites are extremely valuable. The small power dividers manufactured by this process can achieve accurate power distribution while meeting size and weight restrictions, ensuring the reliability and effectiveness of satellite communications. For example, the received uplink signal is accurately distributed to different downlink channels to achieve multi-beam coverage of satellite communications.

[0090] In the field of Internet of Things technology, multiple sensor nodes in the wireless sensor network of the Internet of Things may share radio frequency resources. High-precision small power divider technology can be used to manufacture power dividers in sensor nodes to accurately distribute limited radio frequency power to different sensor functional modules or antennas. Since sensor nodes are usually very small, small power divider technology can meet their size requirements. At the same time, high-precision power distribution helps to improve the communication efficiency and reliability between sensor nodes, thereby achieving effective support for Internet of Things application scenarios such as environmental monitoring and smart homes.

[0091] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A small high-precision power divider based on a three-layer PCB board, characterized in that: include: A first conductive layer (1), wherein the first conductive layer (1) comprises: A first circuit (2) having a first input port and two first output ports; The second conductive layer (3) is arranged on one side of the first conductive layer (1), and the second conductive layer (3) comprises: A plurality of second circuits (4), each having a second input port and two second output ports, each of the second input ports being electrically connected to each of the first output ports in a one-to-one correspondence; The third conductive layer (5) is arranged on a side of the second conductive layer (3) facing away from the first conductive layer (1), and the third conductive layer (5) comprises: A plurality of third circuits (6), each having a third input port and two third output ports, each of the third input ports being electrically connected to each of the second output ports in a one-to-one correspondence; The orthographic projections of the first circuit (2) and the plurality of second circuits (4) on the third conductive layer (5) at least partially intersect with the area where the plurality of third circuits (6) are located.

2. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 1, characterized in that: The first conductive layer (1), the second conductive layer (3) and the third conductive layer (5) are all provided with metallized vias; The second input port is electrically connected to the first output port through the metallized via, and the third input port is electrically connected to the second output port through the metallized via; The area where the orthographic projection of the first circuit (2) on the third conductive layer (5) is located is the first area, the area where the orthographic projections of the plurality of second circuits (4) on the third conductive layer (5) are located is the second area, the area where the plurality of third circuits (6) are located is the third area, and the ratio of the overlapping area of ​​the first area, the second area and the third area to the area of ​​the third conductive layer (5) is a, and 30%<a<60%.

3. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 1, characterized in that: The third conductive layer (5) has a first side edge and a second side edge which are arranged opposite to each other in a first direction, and the first direction is the same as a width direction of the third conductive layer (5); The orthographic projections of the first input port and the first output port on the third conductive layer (5) are oriented toward the first side edge and the second side edge respectively; The orthographic projections of the second input port and the second output port on the third conductive layer (5) are oriented toward the second side edge and the first side edge respectively; The orthographic projections of the third input port and the third output port on the third conductive layer (5) are oriented toward the first side edge and the second side edge respectively.

4. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 1, characterized in that: The first circuit (2) comprises: Two first microstrip lines are arranged opposite to each other in a second direction and two ends of the first microstrip lines are respectively connected to the first input port and one of the first output ports, the second direction being the same as the length direction of the first conductive layer (1); a plurality of first resistors, arranged at intervals in a first direction and connected between two of the first microstrip lines, wherein the first direction is the same as the width direction of the first conductive layer (1); The second circuit (4) comprises: Two second microstrip lines are arranged opposite to each other in the second direction and two ends of the second microstrip lines are respectively connected to the second input port and one of the second output ports; The third circuit (6) comprises: Two third microstrip lines are arranged opposite to each other in the second direction and two ends of the third microstrip lines are respectively connected to the third input port and one of the third output ports; A plurality of third resistors are arranged at intervals in the first direction and are all connected between two of the third microstrip lines.

5. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 4, characterized in that: The two first microstrip lines are mirror images of each other; The first microstrip line comprises: a first horizontal segment (21), one end of which is connected to the first input port, the extension direction of the first horizontal segment (21) being perpendicular to a first direction, the first direction being the same as a width direction of the first conductive layer (1); a second horizontal section (22), arranged on a side of the first horizontal section (21) close to the first output port, the extension direction of the second horizontal section (22) being perpendicular to the first direction; a plurality of third horizontal segments (23) arranged in parallel between the first horizontal segment (21) and the second horizontal segment (22) in the first direction, wherein the extension direction of the third horizontal segments (23) is perpendicular to the first direction; a plurality of first vertical segments (24), the first horizontal segment (21), the second horizontal segment (22) and the plurality of third horizontal segments (23) being connected in series, the first vertical segments (24) extending in the same direction as the first direction, wherein the plurality of first vertical segments (24) are divided into a connection segment 1 and a connection segment 2, in the second direction, the connection segment 1 is located on a side of the connection segment 2 close to the first input port, the extension directions of the connection segments 1 all overlap, and the extension directions of the connection segments 2 all overlap; a second vertical section (25), one end of which is electrically connected to the second horizontal section (22), and the other end of which is electrically connected to one of the first output ports, the extension direction of the second vertical section (25) being the same as the first direction; Wherein, two ends of each of the first resistors are electrically connected to opposite connection segments 1 of the two first microstrip lines respectively; The first microstrip line, the second microstrip line and the third microstrip line are arranged in proportion.

6. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 2, characterized in that: A grounding layer is provided on both the first conductive layer (1) and the third conductive layer (5); Wherein, the first conductive layer (1) and the third conductive layer (5) are both electrically connected to the adjacent ground layer through the metallized vias.

7. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 1, characterized in that: A plurality of first elements related to the input matching network are arranged on the first conductive layer (1); A plurality of second elements related to the output matching network are arranged on the third conductive layer (5); Gaps are provided on the first conductive layer (1) and the third conductive layer (5) to separate the first elements from the second elements; Wherein, the gap is filled with electromagnetic shielding material.

8. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 6, characterized in that: The power divider also includes: A plurality of electromagnetic shielding covers are respectively disposed at the first input port and each of the third output ports and are electrically connected to the corresponding ground layer.

9. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 1, characterized in that: The thickness of the first conductive layer (1) is the same as that of the third conductive layer (5) and is a first thickness, the thickness of the second conductive layer (3) is a second thickness, the ratio of the first thickness to the second thickness is a, and 0.4<a<0.

6.

10. The small-sized high-precision power divider based on three-layer PCB board as claimed in claim 9, characterized in that: The first conductive layer (1), the second conductive layer (3) and the third conductive layer (5) all use a substrate made of the same material, the dielectric constant of the substrate is 4.2-4.6, and the loss tangent is 0.02; The thickness of the first conductive layer (1) and the third conductive layer (5) are both 0.18-0.22 mm; The thickness of the second conductive layer (3) is 0.38-0.42 mm.

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