A high-frequency signal combination grounding method and system, and an electronic device with the same

Abstract

The embodiment of the present disclosure provides a high-frequency signal combined grounding method and system, and an electronic device with the same. The method comprises the following steps: providing a circuit board and a built-in antenna; determining at least one first grounding point on the circuit board, wherein the first grounding point is a grounding end of the circuit board, and the first grounding point is electrically connected to one end of a grounding wire of a coaxial line of the built-in antenna; determining the position of at least one second grounding point on the circuit board; wherein the area of the second grounding point is calculated according to the frequency of a high-frequency signal; removing the solder mask layer at the determined position of the second grounding point on the circuit board to expose a grounding point with an area equal to that of the second grounding point; and covering part of a metal layer of the built-in antenna on the exposed grounding point to form an equivalent flat plate capacitor. The combined grounding method is simple and cost-effective, and can effectively prevent interference of low-frequency signals and high-frequency signals.

Description

Technical Field

[0001] This disclosure relates to the field of electronic circuit technology, and in particular to a high-frequency signal combination grounding method, system, and electronic device having the same. Background Technology

[0002] In high-frequency signal processing, electromagnetic radiation and interference are often generated due to the operation of electronic equipment and communication. Grounding, as a common means of suppressing and preventing electromagnetic radiation, typically employs a single-point grounding method in existing technologies. However, single-point grounding has some limitations, such as easily causing crosstalk in the grounding loop and variations in grounding voltage, thereby affecting signal transmission and processing performance. Summary of the Invention

[0003] The purpose of this disclosure is to provide a high-frequency signal combination grounding method, system, and electronic device having the same, thereby solving the aforementioned problems existing in the prior art.

[0004] To achieve the above objectives, the technical solutions adopted in the embodiments of this disclosure are as follows:

[0005] This disclosure provides a high-frequency signal combined grounding method, the method comprising:

[0006] Provides circuit boards and built-in antennas;

[0007] At least one first grounding point is defined on the circuit board, wherein the first grounding point is the grounding terminal of the circuit board and is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna; the first grounding point is used to prevent interference from low-frequency signals and other stray currents.

[0008] The location of at least one second grounding point is determined on the circuit board; wherein, the area of ​​the second grounding point is calculated based on the frequency of the high-frequency signal;

[0009] Remove the solder mask layer at the determined second grounding point location on the circuit board to expose a grounding point with an area equal to that of the second grounding point;

[0010] A portion of the metal layer of the built-in antenna is covered over the exposed grounding point to form an equivalent planar capacitor;

[0011] The equivalent parallel plate capacitor is used to form an impedance path to suppress corresponding high-frequency noise, thereby removing and reducing electromagnetic interference from high-frequency signals.

[0012] For example, calculating the area of ​​the second grounding point based on the frequency of the high-frequency signal includes:

[0013] The capacitance value of the equivalent parallel plate capacitor is inversely proportional to the distance between the capacitor plates and the area of ​​the capacitor plates, i.e., C = εA / d, where C represents the capacitance value, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, and d represents the distance between the capacitor plates. The exposed grounding point and the metal layer covering it are equivalent to the capacitor plates.

[0014] And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, C is the capacitance, and the resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L=(μ0×μr×N 2 ×A) / l, where μ0≈4π×10 -7 H / m is the permeability in vacuum, μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, N is the number of turns of the coil, there is only one metal layer, and the number of turns of the coil is 1; A is the cross-sectional area of ​​the coil, which is the area of ​​the capacitor plate; l is the length of the coil, which is the distance between the capacitor plates.

[0015] The relationship between the area of ​​the equivalent parallel plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε.

[0016] For example, the first grounding point is connected to one end of the grounding wire on the same axis as the built-in antenna by welding.

[0017] For example, after covering the grounding point with a portion of the metal layer of the built-in antenna, the method further includes: applying an adhesive between the grounding point and the portion of the metal layer covering it, wherein the thickness of the adhesive is equal to the distance between the capacitor plates of an equivalent parallel-plate capacitor.

[0018] For example, both the grounding point and the metal layer are made of copper.

[0019] Another aspect of this disclosure provides a high-frequency signal combined grounding system, the system including a circuit board and a built-in antenna, the circuit board including at least one first grounding point and a second grounding point respectively disposed thereon;

[0020] The first grounding point is the grounding terminal of the circuit board, and the first grounding point is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna; the first grounding point is used to prevent interference from low-frequency signals and other stray currents.

[0021] The second grounding point includes the grounding point of the circuit board and a portion of the metal layer of the built-in antenna covering the grounding point, wherein the grounding point and the portion of the metal layer form an equivalent parallel plate capacitance; wherein the area of ​​the second grounding point is obtained according to the frequency of the high-frequency signal;

[0022] The equivalent parallel plate capacitor is used to form an impedance path to suppress corresponding high-frequency noise, thereby removing and reducing electromagnetic interference from high-frequency signals.

[0023] For example, the area of ​​the equivalent parallel plate capacitor is obtained based on the frequency of the high-frequency signal, including:

[0024] The capacitance value of the equivalent parallel plate capacitor is inversely proportional to the distance between the capacitor plates and the area of ​​the capacitor plates, i.e., C = εA / d, where C represents the capacitance value, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, and d represents the distance between the capacitor plates. The capacitor plates are the exposed grounding point and the metal layer covering it.

[0025] And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, C is the capacitance, and the resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L=(μ0×μr×N 2 ×A) / l, where μ0≈4π×10 -7 H / m is the permeability in vacuum, μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, N is the number of turns of the coil, there is only one metal layer, and the number of turns of the coil is 1; A is the cross-sectional area of ​​the coil, which is the area of ​​the capacitor plate; l is the length of the coil, which is the distance between the capacitor plates.

[0026] The relationship between the area of ​​the equivalent parallel plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε.

[0027] For example, both the grounding point and the metal layer are made of copper.

[0028] For example, the first grounding point and the second grounding end of the coaxial line of the built-in antenna are welded together; an adhesive is provided between the grounding point of the second grounding point and the metal layer covering it.

[0029] Another aspect of this disclosure provides an electronic device having a high-frequency signal combination grounding system as described above.

[0030] The beneficial effects of the embodiments disclosed herein are:

[0031] The embodiments disclosed herein design an equivalent capacitor, i.e., a second grounding point, on the original circuit board to ground the high-frequency signal, thereby forming a low-impedance grounding method that suppresses the corresponding high-frequency signal; the first grounding point is used to prevent interference from low-frequency signals and other stray currents; the combined grounding method is simple, requiring only corresponding adjustments to the original circuit board, and is characterized by reliability, economy, ease of installation and maintenance, and is suitable for various high-frequency signal processing applications. Attached Figure Description

[0032] Figure 1 This is a schematic flowchart of a high-frequency signal combination grounding method according to an embodiment of the present disclosure;

[0033] Figure 2 This is a capacitance equivalent grounding map of the second grounding point in a high-frequency signal combined grounding method according to an embodiment of this disclosure;

[0034] Figure 3 This is a schematic diagram of the structure of an equivalent parallel plate capacitor for high-frequency signal combination grounding according to an embodiment of this disclosure;

[0035] Figure 4 This is a schematic diagram of the structure of the built-in antenna in a high-frequency signal combination grounding method according to an embodiment of this disclosure;

[0036] Figure 5 This is a schematic diagram of the structure of a high-frequency signal combined grounding system according to an embodiment of this disclosure;

[0037] Figures 6 to 8 This is a physical diagram of a high-frequency signal combined grounding system according to an embodiment of this disclosure. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the embodiments of this disclosure will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the embodiments of this disclosure and are not intended to limit the embodiments of this disclosure.

[0039] like Figure 1 As shown, this disclosure provides a high-frequency signal combination grounding method, the method comprising:

[0040] Step S1: Provide the circuit board and built-in antenna.

[0041] The circuit board in this embodiment is a PCB board. The circuit board 100 can be an existing PCB board, which has a circuit layer and a solder mask layer 300. The solder mask layer is commonly known as green solder mask. Multiple grounding terminals GND on the circuit form the grounding network of the circuit board, i.e., the ground plane. A grounding layer can also be set separately on the circuit board, which is not limited here. The grounding network and the grounding layer serve as shielding layers, and their material can be copper. The built-in antenna 200 includes a substrate, a metal layer disposed on the substrate, and a coaxial line connected to the metal layer. The substrate is also the shielding layer, and the coaxial line passes through the shielding layer and connects to the circuit board. The routing method and width of the metal layer are set according to the actual situation. Under the excitation of the circuit in the circuit board, the metal layer can generate an antenna effect. The material of the metal layer can also be copper. The coaxial line includes a feed line connected to the circuit on the circuit board, i.e., a signal line, and a grounding line wrapped around the outside of the feed line. The grounding line is connected to the metal layer and the grounding terminal on the circuit board at both ends, and the grounding line serves to shield external signal interference. This embodiment improves upon the original circuit board.

[0042] Step S2: Determine at least one first grounding point on the circuit board. The first grounding point is the grounding terminal of the circuit board and is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna. The first grounding point is used to prevent interference from low-frequency signals and other stray currents.

[0043] In this embodiment, multiple grounding points are arranged at appropriate intervals on the existing circuit board. The first grounding point 110 is a ground terminal of the circuit board, specifically a ground terminal GND of the circuit board's grounding network, or a grounding point on a separately configured ground layer. One end of the grounding wire of the coaxial cable of the built-in antenna is electrically connected to the first grounding point via a solder pad. Figure 4 As shown, the other end of the ground wire of the coaxial line of the built-in antenna is connected to the metal layer of the built-in antenna. One end of the feed line of the coaxial line of the built-in antenna is connected to the metal layer of the built-in antenna, and the other end of the feed line of the coaxial line of the built-in antenna is connected to the corresponding circuit on the circuit board to transmit signals.

[0044] For example, the first grounding point is connected to one end of the grounding wire on the same axis as the built-in antenna by welding.

[0045] In this embodiment, one end of the grounding wire of the coaxial line of the built-in antenna can be soldered to the pad on the first grounding point, or directly soldered to a separately provided grounding layer. The first grounding point in this embodiment is used to prevent interference from low-frequency signals and other stray currents.

[0046] Step S3: Determine the location of at least one second grounding point on the circuit board; wherein, the area of ​​the second grounding point is calculated based on the frequency of the high-frequency signal.

[0047] In this embodiment of the disclosure, the second grounding point 120 is used to solve the problem of electromagnetic interference and signal loss caused by grounding in high-frequency signal processing.

[0048] For example, calculating the area of ​​the second grounding point based on the frequency of the high-frequency signal includes:

[0049] The capacitance value of the equivalent parallel plate capacitor is inversely proportional to the distance between the capacitor plates and the area of ​​the capacitor plates, i.e., C = εA / d, where C represents the capacitance value, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, and d represents the distance between the capacitor plates. The exposed grounding point and the metal layer covering it in the subsequent step S4 are equivalent to the capacitor plates.

[0050] And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, C is the capacitance, and the resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L=(μ0×μr×N 2 ×A) / l, where μ0≈4π×10 -7 H / m is the permeability in vacuum; μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, typically the relative permeability of copper; N is the number of turns in the coil; if the conductive sheet has only one layer, the number of turns in the coil is 1; A is the cross-sectional area of ​​the coil, taking the area of ​​the capacitor plate as the cross-sectional area of ​​the coil; l is the length of the coil, taking the distance between the capacitor plates as the length of the coil.

[0051] The relationship between the area of ​​the equivalent parallel plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε.

[0052] Step S4: Remove the solder mask layer at the determined second grounding point location on the circuit board to expose a grounding point with an area equal to that of the second grounding point.

[0053] In this embodiment of the disclosure, removing the solder mask layer 300 on the ground terminal GND or the separate ground layer on the circuit board is equivalent to opening a window on the circuit board to expose the ground terminal GND121 with an area equal to that of the second ground point.

[0054] Step S5: Cover the exposed grounding point with a portion of the metal layer of the built-in antenna to form an equivalent planar capacitor; wherein, the equivalent planar capacitor is used to provide a low-impedance path to suppress corresponding high-frequency noise in order to absorb and disperse electromagnetic interference.

[0055] like Figure 2 As shown, at a specific frequency, the impedance is at its minimum, equivalent to grounding. Figure 3 As shown, in this embodiment, the equivalent parallel-plate capacitor forms a low-impedance grounding method at the corresponding frequency, thereby effectively dispersing and absorbing electromagnetic radiation, thus improving the quality and stability of high-frequency signal transmission. Other metal layers of the built-in antenna can be disposed in the casing of the electronic device, etc., and are not limited here.

[0056] For example, after covering the grounding point with a portion of the metal layer of the built-in antenna, the method further includes: applying adhesive between the grounding point and the portion of the metal layer covering it, wherein the thickness of the adhesive is equal to the distance between the capacitor plates of an equivalent parallel-plate capacitor. The thickness of the adhesive should not be too large to ensure that the area of ​​the second grounding point is moderate, and the thickness of the adhesive can be adjusted according to the actual situation.

[0057] This disclosure illustrates how to determine the area of ​​the equivalent plate capacitance based on a high-frequency signal. To ground the high-frequency signal through the equivalent capacitance, a question arises: what is the frequency range of the signal that needs to be grounded, and what is the equivalent capacitance corresponding to that frequency? Knowing this equivalent capacitance is essentially equivalent to calculating the equivalent capacitance between two copper plates.

[0058] In other words, as long as the frequency of the high-frequency signal that needs to be eliminated (grounded) is known, a window can be opened on the antenna and PCB board, the required area can be calculated, and the equivalent plate capacitance area can be calculated based on the frequency value. The corresponding length and width can then be designed to complete the grounding of the high-frequency signal.

[0059] First, understand the equivalent characteristics of a parallel-plate capacitor. There is a direct relationship between the capacitance value and the area of ​​the plates. According to the basic principle of parallel-plate capacitors, the capacitance value is inversely proportional to the distance between the capacitor plates and inversely proportional to the area of ​​the capacitor plates; that is, the capacitance value increases as the area of ​​the capacitor plates increases. The mathematical expressions for the capacitance value, the distance between the capacitor plates, and the area of ​​the capacitor plates can be expressed as:

[0060] C=εA / d

[0061] Where C represents the capacitance, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, and d represents the distance between the capacitor plates. This formula shows that the capacitance is directly proportional to the area of ​​the capacitor plates and inversely proportional to the distance between the capacitor plates.

[0062] The resonant frequency can be calculated using the following formula:

[0063]

[0064] Where f is the resonant frequency, L is the inductance, and C is the capacitance.

[0065] In other words, based on the above calculation formula and the specific window area on the PCB board, we can obtain A and the gap d. Since all of these parameters are known, we can achieve any high-frequency signal that we want to ground.

[0066] Using actual PCB boards and external antennas, and actual data, we can illustrate the specific parameters for achieving multi-point grounding.

[0067] In reality, for antenna signals, specifically, the frequency range of 4G antennas includes 700MHz, 800MHz, 900MHz, 1800MHz, 1900MHz, 2100MHz, and 2600MHz. If the signal is on a coaxial cable, these frequency bands are the useful antenna signals. However, if electromagnetic crosstalk or other harmonics appear on the GND network, these are noise signals that need to be filtered out. Here, we utilize the equivalent grounding effect of a parallel plate capacitor to remove these interfering noise signals on the GND.

[0068] According to the formula for resonant frequency:

[0069]

[0070] Where f is the resonant frequency (in Hertz), L is the inductance (in Henry), and C is the capacitance (in Farad).

[0071] First, the inductance needs to be calculated. The formula for calculating inductance is:

[0072] L=(μ0×μr×N 2 ×A) / l

[0073] Where μ0≈4π×10 -7 H / m is the permeability in vacuum, μr≈1 is the relative permeability of copper, N is the number of turns of the coil, A is the cross-sectional area of ​​the coil, and l is the length of the coil.

[0074] Since the distance between the copper foils is 0.02mm (i.e., 2×10), -5 m) represents the distance between the exposed grounding point and the metal layer covering it. This distance can be understood as the thickness of the adhesive bonding between two different media; this distance can be used as the length l of the coil. Also, since it is square, the area of ​​the copper foil can be used as the cross-sectional area A of the coil. Assuming there is only one loop of copper foil, then N = 1.

[0075] The PCB board's surface layer is copper foil. Assuming no solder mask is applied and the exposed area is a square, the distance 'd' between two square copper foils is calculated. The antenna has adhesive backing with a thickness of 0.02mm. Therefore, the distance between the two copper foils on the upper and lower layers is 0.02mm.

[0076] First, convert the distance d to meters, i.e., 0.02 mm = 0.02 × 10⁻⁶. -3 m = 2 × 10 -5 m.

[0077] Now, the result can be calculated using the formula for equivalent capacitance:

[0078] C=(ε0×εr×A) / d

[0079] Where, ε0≈8.854×10 -12 F / m is the permittivity in vacuum, εr≈1 is the relative permittivity of copper, and d=2×10 -5 m is the distance between the square copper sheets.

[0080] LC=[(μ0×μr×N 2 ×A) / l]*[(ε0×εr×A) / d]=

[0081] [μ0×μr×N 2 ×A 2 ×ε0×εr] / ld

[0082] The resonant frequency can be calculated using the following formula:

[0083]

[0084] Where f is the resonant frequency, L is the inductance, and C is the capacitance.

[0085] f≈2400MHz (The noise interference that needs to be removed is expected to reach this frequency and needs to be filtered out).

[0086] That is, LC = (1 / 2πf) 2 That is, [μ0×μr×N] 2 ×A 2 [×ε0×εr] / ld=(1 / 2πf) 2 μ0×μr×N 2 ×A 2 ×ε0×εr=ld / (2πf) 2 That is, A 2 =ld / [(2πf) 2 ×ε0×εr×μ0×μr×N 2 ];ε0≈8.854×10 -12 F / m; εr≈1; N=1; μ0≈4π×10 -7 H / m; μr≈1; l=2×10 -5 m; d = 2 × 10 -5 m; π = 3.14; substituting these values ​​into the calculation yields:

[0087] A2 ≈0.00000001[(m 2 ) 2 ] = 1 × 10 -8 [(m 2 ) 2 ] 、， That is, A≈0.0001m 2 =1×10 -4 m 2；

[0088] Therefore, the effective window area between the upper and lower base plates is 0.0001m². If it is a square area, that is, the side length is 0.01m². So, leaving a square with a side length of 1cm for the window area is sufficient to satisfy the purpose of removing high-frequency noise signals by the equivalent grounding effect of the plate capacitor.

[0089] That is, with a window area of ​​approximately this size, the resonant frequency of the equivalent capacitance is about 2.4 GHz, thus achieving high-frequency signal grounding.

[0090] The solder joint between the coaxial grounding wire of the built-in antenna and the grounding terminal of the circuit board in this embodiment is the first grounding point; the bonding point between the metal layer of the built-in antenna and the grounding point of the PCB board window is the equivalent high-frequency signal grounding point of the equivalent planar capacitor. Multi-point grounding is achieved without the need for additional wires. Because leading wires out from the antenna alone, under high-frequency (GHz) signals, any raised pads or leads may cause new antenna effects. Therefore, it is best to avoid connecting leads to the already debugged antenna, but to achieve multi-point grounding under high-frequency signals, the high-frequency grounding characteristics of capacitors are utilized to achieve solderless multi-point grounding. Furthermore, the size of the opening area can be adjusted according to the high-frequency interference frequency during actual debugging to optimize multi-point grounding.

[0091] The equivalent grounding principle of the parallel plate capacitors for high-frequency signals in this disclosure is based on the conduction characteristics of capacitors under high-frequency signals. In the high-frequency range, the on-resistance of a capacitor decreases with increasing frequency; therefore, parallel plate capacitors can provide a low-impedance path, giving them equivalent grounding characteristics in the high-frequency range. This method is commonly used to suppress high-frequency noise through low-impedance paths, guiding high-frequency noise to the ground and reducing interference to other circuits; it can reduce crosstalk and transmission loss between circuits, improve signal quality and stability, and enhance signal transmission quality; it can also reduce electromagnetic interference, as a well-designed grounding system can reduce the influence of external electromagnetic fields on the circuit and improve its anti-interference capability.

[0092] like Figure 5As shown, this disclosure provides a high-frequency signal combined grounding system. The system includes a circuit board 100 and a built-in antenna 200. The circuit board 100 includes at least one first grounding point 110 and a second grounding point 120 respectively disposed thereon. The first grounding point 110 is the grounding terminal of the circuit board and is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna. The first grounding point 110 is used to prevent interference from low-frequency signals and other stray currents. The second grounding point 120 includes a grounding point 121 of the circuit board and a partial metal layer 122 of the built-in antenna covering the grounding point. The grounding point 121 and the partial metal layer 122 form an equivalent parallel plate capacitance. The area of ​​the second grounding point 120 is obtained according to the frequency of the high-frequency signal. The equivalent parallel plate capacitance is used to form an impedance path to suppress corresponding high-frequency noise, so as to remove and reduce electromagnetic interference of high-frequency signals.

[0093] This disclosure addresses high-frequency signal transmission environments and, based on the characteristics of capacitors—blocking DC and passing AC—the capacitor effectively acts as a short-circuit ground at high frequencies. This provides a basis for multi-point grounding of the entire high-frequency signal circuit.

[0094] like Figures 6 to 8 As shown, this disclosure proposes a multi-point combined grounding system to address electromagnetic interference and signal loss caused by grounding in high-frequency signal processing. The system utilizes multiple grounding point methods, directly soldering grounding and equivalent grounding for high-frequency signals. Multiple grounding points contact each other through materials within the PCB board, forming an equivalent parallel-plate capacitance. At corresponding frequencies, this creates a low-impedance grounding method, effectively dispersing and absorbing electromagnetic radiation, thereby improving signal transmission quality and stability. Furthermore, the system is reliable, economical, easy to install and maintain, and suitable for various high-frequency signal processing applications.

[0095] For example, the area of ​​the equivalent parallel plate capacitor is obtained based on the frequency of the high-frequency signal, including: the capacitance value of the equivalent parallel plate capacitor is inversely proportional to the distance between the capacitor plates and the area of ​​the capacitor plates, i.e., C = εA / d, where C represents the capacitance value, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, d represents the distance between the capacitor plates, and the capacitor plates are the exposed grounding point and the metal layer covering it.

[0096] And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, C is the capacitance, and the resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L=(μ0×μr×N 2 ×A) / l, where μ0≈4π×10 -7H / m is the permeability in vacuum, μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, N is the number of turns of the coil, there is only one metal layer, and the number of turns of the coil is 1; A is the cross-sectional area of ​​the coil, which is the area of ​​the capacitor plate; l is the length of the coil, which is the distance between the capacitor plates.

[0097] The relationship between the area of ​​the equivalent parallel plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε.

[0098] For example, both the grounding point and the metal layer are made of copper. Copper has good electrical conductivity and is cost-effective.

[0099] For example, the first grounding point 110 is welded to the second grounding end of the coaxial line of the built-in antenna; an adhesive 123 is provided between the grounding point 121 of the second grounding point 120 and the metal layer 122 covering it. The thickness of the adhesive is the distance between the capacitor plates of the equivalent parallel plate capacitor, and the adhesive is applied evenly and with a moderate thickness.

[0100] Another aspect of this disclosure provides an electronic device having a high-frequency signal combination grounding system as described above.

[0101] The above description is only a preferred embodiment of the present disclosure. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present disclosure, and these improvements and modifications should also be considered within the protection scope of the present disclosure.

Claims

1. A high-frequency signal combination grounding method, characterized in that, The method includes: Provides circuit boards and built-in antennas; At least one first grounding point is defined on the circuit board, wherein the first grounding point is the grounding terminal of the circuit board and is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna; the first grounding point is used to prevent interference from low-frequency signals and other stray currents. The location of at least one second grounding point is determined on the circuit board; wherein, the area of ​​the second grounding point is calculated based on the frequency of the high-frequency signal; Remove the solder mask layer at the determined second grounding point location on the circuit board to expose a grounding point with an area equal to that of the second grounding point; A portion of the metal layer of the built-in antenna is covered over the exposed grounding point to form an equivalent planar capacitor; The equivalent parallel plate capacitor is used to form an impedance path to suppress corresponding high-frequency noise, thereby removing and reducing electromagnetic interference from high-frequency signals.

2. The grounding method according to claim 1, characterized in that, The calculation of the area of ​​the second grounding point based on the frequency of the high-frequency signal includes: The capacitance of the equivalent parallel-plate capacitor is inversely proportional to the distance between the capacitor plates, i.e., C = ε0 * εr * A / d, where C represents the capacitance, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, and d represents the distance between the capacitor plates. The exposed grounding point and the metal layer covering it are equivalent to the capacitor plates; ε0 ≈ 8.854 × 10⁻¹² F / m is the dielectric constant in vacuum, and εr ≈ 1 is the relative dielectric constant of copper. And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, and C is the capacitance. The resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L = (μ0 × μr × N) 2 × A) / l, where μ0≈4π×10 -7 H / m is the permeability in vacuum, μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, N is the number of turns of the coil, there is only one metal layer, and the number of turns of the coil is 1; A is the cross-sectional area of ​​the coil, which is the area of ​​the capacitor plate; l is the length of the coil, which is the distance between the capacitor plates. The relationship between the area of ​​the equivalent parallel-plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε0.

3. The grounding method according to claim 1 or 2, characterized in that, The first grounding point is connected to one end of the grounding wire on the same axis as the built-in antenna by welding.

4. The grounding method according to claim 1 or 2, characterized in that, After covering the grounding point with a portion of the metal layer of the built-in antenna, the method further includes: applying an adhesive between the grounding point and the portion of the metal layer covering it, wherein the thickness of the adhesive is equal to the distance between the capacitor plates of an equivalent parallel-plate capacitor.

5. The method according to claim 1 or 2, characterized in that, Both the grounding point and the metal layer are made of copper.

6. A high-frequency signal combined grounding system, characterized in that, The system includes a circuit board and a built-in antenna. The circuit board includes at least one first grounding point and a second grounding point respectively disposed thereon. The first grounding point is the grounding terminal of the circuit board, and the first grounding point is electrically connected to one end of the grounding wire of the coaxial line of the built-in antenna; the first grounding point is used to prevent interference from low-frequency signals and other stray currents. The second grounding point includes the grounding point of the circuit board and a portion of the metal layer of the built-in antenna covering the grounding point, wherein the grounding point and the portion of the metal layer form an equivalent parallel plate capacitance; wherein the area of ​​the second grounding point is obtained according to the frequency of the high-frequency signal; The equivalent parallel plate capacitor is used to form an impedance path to suppress corresponding high-frequency noise, thereby removing and reducing electromagnetic interference from high-frequency signals.

7. The system according to claim 6, characterized in that, The area of ​​the equivalent parallel plate capacitor is obtained based on the frequency of the high-frequency signal, including: The capacitance of the equivalent parallel-plate capacitor is inversely proportional to the distance between the capacitor plates and the area of ​​the capacitor plates, i.e., C = ε0 * εr * A / d, where C represents the capacitance, ε represents the dielectric constant, A represents the area of ​​the capacitor plates, d represents the distance between the capacitor plates, and the exposed grounding point and the metal layer covering it are equivalent to the capacitor plates; ε0 ≈ 8.854 × 10⁻¹² F / m is the dielectric constant in vacuum, and εr ≈ 1 is the relative dielectric constant of copper. And the relationship between the resonant frequency of the high-frequency signal and the capacitance, i.e. Where f is the resonant frequency of the high-frequency signal, L is the inductance, and C is the capacitance. The resonant frequency of the high-frequency signal is used as the operating frequency of the high-frequency signal; L = (μ0 × μr × N) 2 × A) / l, where μ0≈4π×10 -7 H / m is the permeability in vacuum, μr≈1 is the relative permeability of the equivalent parallel plate capacitor material, N is the number of turns of the coil, there is only one metal layer, and the number of turns of the coil is 1; A is the cross-sectional area of ​​the coil, which is the area of ​​the capacitor plate; l is the length of the coil, which is the distance between the capacitor plates. The relationship between the area of ​​the equivalent parallel-plate capacitor, the distance between the capacitor plates, and the frequency of the high-frequency signal is obtained as follows: A = d / 4π 2 f 2 Lε.

8. The system according to claim 6, characterized in that, Both the grounding point and the metal layer are made of copper.

9. The system according to claim 6, characterized in that, The first grounding point and the second grounding end of the coaxial line of the built-in antenna are connected by welding; an adhesive is provided between the grounding point of the second grounding point and the metal layer covering it.

10. An electronic device, characterized in that, The electronic device has the high-frequency signal combination grounding system as described in any one of claims 6 to 9.

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