Onboard antenna and electronic device

Abstract

The invention provides an onboard antenna and an electronic device, the onboard antenna is arranged on a substrate and comprises a feeder line, a first radiator and a parasitic ground unit, and the feeder line, the first radiator and the parasitic ground unit are all arranged in a clearance area of the substrate to form a first antenna. The first antenna is formed by the feeder line arranged in the clearance area of the substrate, the first radiator and the parasitic ground unit, so that a high-performance antenna structure can be realized under the condition of not increasing the area of the substrate, and miniaturization of the electronic device is facilitated. Furthermore, on the basis of forming the first antenna, the feeder line, the second radiator and the ground plane of the substrate are utilized to form the second antenna, and the space of the first antenna and the space of the second antenna in the substrate can be saved by sharing the feeder line and the clearance area, so that the requirement of wide-range working frequency is met under the condition that the space of the substrate is limited.

Description

Technical Field

[0001] The present disclosure relates to the field of antenna technology, and in particular to a board-mounted antenna and an electronic device. Background Art

[0002] LTE (Long Term Evolution) antennas operate in the 700MHz to 2.7GHz frequency band, which is divided into mid-high frequency, medium frequency, and low frequency. The low frequency band for LTE antennas is 703MHz to 960MHz, the medium frequency band is 1GHz to 2.4GHz, and the high frequency band is above 2.4GHz, for example, 2570MHz to 2700MHz. This means that the radiator of an LTE antenna must cover the 700MHz to 2.7GHz band. However, due to the limited space on the PCB board of an actual product, printing the radiator on the PCB would take up a lot of space, making it impractical to implement in the product. Other onboard multi-band antennas, such as cellular 5G (fifth-generation mobile communication technology) antennas, cellular 6G (sixth-generation mobile communication technology) antennas, 2.4G Wi-Fi antennas / 5G Wi-Fi antennas, 1.575G GPS antennas / 5G Wi-Fi antennas, 2.4G Bluetooth antennas / 5G Wi-Fi antennas, etc., also have the problem that the radiator cannot be implemented in products with limited space on the PCB board. Summary of the Invention

[0003] The technical problem to be solved by the present disclosure is to overcome the defect in the prior art that the radiators of on-board multi-band antennas such as LTE antennas, cellular 5G antennas, and cellular 6G antennas cannot be implemented in products with limited PCB board space, and to provide an on-board antenna and electronic device.

[0004] The present disclosure solves the above technical problems through the following technical solutions:

[0005] A first aspect of the present disclosure provides a board-mounted antenna, which is arranged on a substrate and includes a feeder, a first radiator and a parasitic ground unit. The feeder, the first radiator and the parasitic ground unit are all arranged in a clear area of the substrate to form a first antenna.

[0006] Optionally, the onboard antenna further includes a second radiator, the feed line, the second radiator and a ground plane of the substrate form a second antenna, and the parasitic ground unit is connected to the ground plane.

[0007] Optionally, the first radiator and the second radiator share a portion of the radiator, and the portion not shared by the first radiator and the second radiator is separated by a gap.

[0008] Optionally, the frequency band of the first antenna is higher than the frequency band of the second antenna.

[0009] Optionally, the length of the first radiator is consistent with the length of the parasitic ground unit.

[0010] Optionally, at least one first slot is formed between the first radiator and the parasitic ground unit, and a width of the first slot is related to an electrical performance of the first antenna, and the electrical performance of the first antenna is improved as the width of the first slot increases.

[0011] Optionally, the volume of the clearance area is related to the electrical performance of the first antenna, and the electrical performance of the first antenna is improved as the volume of the clearance area increases.

[0012] Optionally, the parasitic ground unit includes at least two parasites, the length directions of some parasites are perpendicular to the length direction of the substrate, and the length directions of some parasites are parallel to the length direction of the substrate.

[0013] Optionally, the length direction of some of the second radiators is perpendicular to the length direction of the substrate, and the length direction of some of the second radiators is parallel to the length direction of the substrate.

[0014] Optionally, in a portion of the second radiator perpendicular to the length direction of the substrate, a minimum distance from the ground plane is positively correlated with the impedance of the second antenna.

[0015] Optionally, a length direction of a portion of the second radiator is parallel to a length direction of a portion of the first radiator.

[0016] Optionally, the length of the second radiator is consistent with the length of the ground plane.

[0017] Optionally, at least one second slot is formed between the second radiator and the parasitic ground unit, and the width of the second slot is related to the electrical performance of the second antenna, and the electrical performance of the second antenna is improved as the width of the second slot increases.

[0018] Optionally, the volume of the clearance area is related to the electrical performance of the second antenna, and the electrical performance of the second antenna is improved as the volume of the clearance area increases.

[0019] Optionally, the onboard antenna further includes an antenna matching component, and the second radiator is electrically connected to the ground plane via an inductor in the antenna matching component.

[0020] Optionally, the first radiator includes a target segment radiator and a first segment radiator, the second radiator includes a target segment radiator and a second segment radiator, the target segment radiator is connected to the first segment radiator, and the target segment radiator is connected to the second segment radiator through an inductor.

[0021] Optionally, the ground pin of the antenna matching component is connected to a first ground pad provided on the substrate.

[0022] Optionally, the ground plane includes a first ground copper foil, the first ground copper foil and the antenna matching component are located on the same layer of the substrate, and the first ground copper foil is connected to the first ground pad.

[0023] Optionally, the ground plane further includes a second ground copper foil, the second ground copper foil and the first ground copper foil are located on different layers of the substrate, and the second ground copper foil is connected to the first ground pad through a first ground via.

[0024] A second aspect of the present disclosure provides an electronic device, comprising the onboard antenna described in the first aspect.

[0025] Optionally, the electronic device includes a radio frequency component provided on the substrate, and a ground pin of the radio frequency component is connected to a second ground pad provided on the substrate.

[0026] Optionally, the ground plane of the substrate includes a third ground copper foil, the third ground copper foil and the RF component are located on the same layer of the substrate, and the third ground copper foil is connected to the second ground pad.

[0027] Optionally, the ground plane further includes a fourth ground copper foil, the fourth ground copper foil and the third ground copper foil are located on different layers of the substrate, and the fourth ground copper foil is connected to the second ground pad through a second ground via.

[0028] On the basis of conforming to the common sense in this field, the above optional conditions can be arbitrarily combined to obtain the preferred embodiments of the present disclosure.

[0029] The positive progress of the present disclosure is that the first antenna is formed by using the feeder, the first radiator and the parasitic ground unit arranged in the clearance area of the substrate, which can achieve a high-performance antenna structure without increasing the substrate area, which is conducive to the miniaturization of electronic devices.

[0030] Furthermore, on the basis of forming the first antenna, the second antenna is formed using the feed line, the second radiator and the ground plane of the substrate. By sharing the feed line and the clearance area, the space of the first antenna and the second antenna in the substrate can be saved, so that the requirements of a wider range of operating frequencies can be met under the condition of limited substrate space. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A top view of a board-mounted multi-frequency antenna on a PCB provided in an embodiment of the present disclosure.

[0032] Figure 2 A partial top view of a board-mounted multi-frequency antenna on a PCB provided in an embodiment of the present disclosure.

[0033] Figure 3 A cross-sectional view of a board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure along the -Z to Z direction in a two-layer PCB board.

[0034] Figure 4 A cross-sectional view of a board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure, taken along the -X to X direction in a two-layer PCB board.

[0035] Figure 5 A cross-sectional view of another board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure, taken along the -Z to Z direction in a two-layer PCB board.

[0036] Figure 6 A cross-sectional view of a board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure along the -Z to Z direction in a four-layer PCB board.

[0037] Figure 7 A cross-sectional view of a board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure, taken along the -X to X direction in a four-layer PCB board.

[0038] Figure 8 Another cross-sectional view of a board-mounted multi-band monopole microstrip antenna provided by an embodiment of the present disclosure along the -X to X direction in a four-layer PCB board.

[0039] Figure 9 A top view of another onboard multi-frequency antenna on a PCB provided in an embodiment of the present disclosure.

[0040] Figure 10 Schematic diagram of return loss test of the board-mounted multi-band monopole microstrip antenna provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0041] The following description of exemplary embodiments of the present disclosure is made in conjunction with the accompanying drawings, including various details of the embodiments of the present disclosure to facilitate understanding. These details should be considered as merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present disclosure. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions and structures are omitted in the following description.

[0042] It should be noted that the terms "first," "second," and the like used in the present disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions, for example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or that are inherent to these processes, methods, products, or apparatus.

[0043] In the disclosed embodiments, the substrate includes a printed circuit board (PCB), a SIP (System in Package), an integrated circuit board (ICB), and the like. SIP (System in Package) is a packaging concept that places all or most of the electronic functions of a system or subsystem within an integrated substrate, with the chip being bonded to the integrated substrate in a 2D or 3D manner. SIP can not only assemble multiple chips, but can also serve as a dedicated processor, DRAM, flash memory, and passive components combined with resistors and capacitors, connectors, antennas, and the like, all mounted on the same substrate. A complete functional unit can be built in a multi-chip package, requiring only a small number of external components to operate. An integrated substrate connects the chip wafer to a high-density substrate via gold wires, such as a WLCSP (Wafer Level Chip Scale Package), a packaging technology that combines wafer-level packaging (WLP) and chip-scale packaging (CSP). A printed circuit board, also known as a printed wiring board or PCB, is an important electronic component that supports electronic components and provides circuit connections for electronic components.

[0044] In the disclosed embodiments, the electrical characteristic parameters of the antenna mainly include input impedance, radiation characteristic parameters, directional diagram, bandwidth, polarization, etc., and the radiation characteristic parameters mainly include radiation efficiency, directional coefficient, gain, etc., which are described in detail below.

[0045] Input Impedance:

[0046] The input impedance Zin is the ratio of the input voltage Uin to the input current Iin. The input impedance Zin is equal to the radiation resistance R r , loss resistance (radiation resistance) R r , and input reactance (radiation resistance) R loss The sum of the three.

[0047]

[0048] Among them, R and Z in The larger the ratio, the better the antenna’s radiation capability. loss is the dielectric loss and line ohmic loss in the circuit; X in Represents reactive loss, that is, the energy stored in the dielectric substrate or in the near field of the antenna. in If X is greater than 0, it means that the stored energy is mainly magnetic field energy. in Less than 0, it means that the stored energy is mainly electric field energy. If X in If it is equal to 0, it means that the antenna is in a resonant state and the stored electric field and magnetic field energies are basically equal.

[0049] The reflection coefficient and standing wave ratio (SWR) are used to measure the degree of matching between an antenna and a transmission line. The characteristic impedance of an SMA (Sub-Miniature version A) connector is typically 50 ohms or 75 ohms, while the impedance of an antenna can vary greatly. If the antenna's impedance is not conjugately matched to the impedance of the SMA connector, high-frequency signals will be reflected at the junction. The reflection coefficient is calculated using the following formula:

[0050]

[0051] Among them, Z L is the input impedance of the antenna, and the characteristic impedance of the system is Z O , is the impedance of the transmission line or SMA connector connected to the antenna. In actual testing, the return loss (RL) can also be used to measure the matching degree between the antenna and the connector. RL can be calculated using the following formula:

[0052]

[0053] According to the reflection coefficient formula, Γ < 1, so RL can be deduced to be greater than 0. The better the match between the antenna and connector, that is, the smaller the impedance difference between them, the larger the RL value. If the antenna and the connecting antenna matching component are matched, RL is infinite. If the antenna and the antenna matching component are completely mismatched, that is, high-frequency electrical signals are completely reflected at the connection, RL is equal to 0. Typically, the system requires RL to be greater than 10dB.

[0054] In the simulation software HFSS (High Frequency Structure Simulator), S is often used. 11 To check the return loss of the antenna. 11 Indicates the reflection loss at port 1, which mainly observes the signal reflection component seen by the sending end. 11 It can be obtained by calculating the return loss RL. The relationship between the two is as follows:

[0055]

[0056] In addition, another commonly used parameter for checking antenna impedance matching performance is the Voltage Standing Wave Ratio (VSWR). The VSWR can be calculated using the following formula:

[0057]

[0058] According to the above formula, VSWR is greater than 1, when Γ=0, that is, Z L =Z O When the VSWR is equal to 1, it indicates that the impedance of the main line and the connector are perfectly matched. As the VSWR increases, the reflected energy increases, and the energy transmitted from the circuit to the antenna and vice versa decreases. Generally, the VSWR of the antenna design should be less than 2.

[0059] Direction Coefficient:

[0060] It is defined as: when the radiation power is the same, the antenna radiation direction The power density at a point on The ratio of the power density of the omnidirectional antenna at that point is shown in the following formula.

[0061]

[0062] Where, The antenna radiates in the direction The directivity coefficient on the antenna is the radiated power, P r is the radiated power of the omnidirectional antenna.

[0063] Since the power density is proportional to the square of the electric field strength, the directivity can also be defined according to the electric field strength in the far zone: when the radiation power is the same, the antenna radiation direction is The square of the electric field strength at a point on The ratio of the electric field strength at that point to the square of the omnidirectional antenna is shown in the following formula.

[0064]

[0065] The radiation direction of the antenna can be determined by θ and To express it, the radiation field intensity generated by the antenna in different radiation directions is different, so the directivity coefficient is also different, which can be expressed by To express the relationship between the directivity and the radiation direction.

[0066] Usually, the directivity coefficient in the maximum radiation direction is used to measure the performance index of the antenna. The larger the directivity coefficient, the more concentrated the radiation of the antenna. During the antenna design process, generally only the maximum directivity coefficient of the antenna is considered.

[0067] Radiant Efficiency:

[0068] In practice, antennas are all lossy, which means that the electromagnetic wave energy radiated is only a part of the energy fed into the antenna, and another part is dissipated in the form of heat energy or stored in the antenna, which is recorded as the loss power P. l The radiated power P r and antenna input power P in The ratio of is the radiation efficiency η, as shown in the following calculation formula:

[0069]

[0070] It can be seen that the efficiency of the antenna is always less than 100%. The antenna power loss can be reduced by selecting a dielectric material with lower loss, thereby improving the antenna efficiency.

[0071] Gain:

[0072] Similar to the definition of directivity, antenna gain is defined as: when the input power is the same, the antenna radiation direction The power density at a point The power density P of the omnidirectional antenna at this point o The ratio is calculated as follows:

[0073]

[0074] in, The antenna radiates in the direction The gain onin is the input power of the antenna, that is, the power input from the excitation source to the antenna, P ino is the input power to the omnidirectional antenna.

[0075] Similarly, the gain can also be defined based on the electric field strength: when the input power is the same, the antenna radiation direction The square of the electric field strength at a point on The ratio of the electric field strength of the omnidirectional antenna to the square of the electric field strength at that point is as shown in the following formula:

[0076]

[0077] The following calculation formula is often used in antenna design to calculate antenna gain:

[0078]

[0079] The gain in the antenna assessment index refers to the maximum gain in a certain operating frequency band, and the gain is usually required to be greater than 2dB.

[0080] Notice two things:

[0081] ① The definitions of directivity and gain are similar, but slightly different. Directivity is calculated when the test antenna and the reference antenna have the same "radiated power," while gain is calculated when the test antenna and the reference antenna have the same "input power." The ratio of radiated power to input power is the radiation efficiency. Therefore, the relationship between directivity and gain can be calculated using the following formula: G = ηD;

[0082] ② When calculating directivity and gain, the results will vary depending on the reference antenna selected. When the reference antenna is an omnidirectional antenna, the gain is calculated in dB or dBi. When the reference antenna is a half-wave dipole antenna, the gain is calculated in dBd, where 1dBd = 2.15dBi.

[0083] Directional Diagram:

[0084] The radiation pattern is a description of the far-field electromagnetic field of the antenna as it changes direction. There are two common ways to show the radiation pattern of an antenna:

[0085] The first method is to observe the electromagnetic field distribution of the antenna through two mutually perpendicular planes, namely the EH plane, where the E plane refers to the plane passing through the maximum radiation direction and parallel to the electric field vector, and the H plane refers to the plane passing through the maximum radiation direction and parallel to the magnetic field vector. The antenna pattern in the HFSS simulation is generally determined by the following methods: ① First, determine the maximum radiation direction by generating the 3D gain pattern of the antenna ② Check the direction of the electric field vector in the antenna model; ③ Combine and the direction of the electric field vector, through the straight line The plane of the electric field vector is the E plane, and the line And the plane perpendicular to the E plane is the H plane; ④ After determining the E plane and H plane, determine the value range of θ and Ψ according to the spherical coordinate system, and thus define the E and H planes in the simulation software. For example: if the dipole antenna is placed vertically on the z axis, the maximum radiation direction of the antenna is along the x axis, and the electric field direction is along the z axis, then its E plane is the xoz plane, which is set in the HFSS simulation as: θ = 0°-360°, The H plane is the xoy plane, which is set to: θ = 90° in the HFSS simulation. For example, for a microstrip antenna placed horizontally on the xoy plane, the microstrip feed line is along the x-axis, the maximum radiation direction of the antenna is along the z-axis, and the electric field direction is along the x-axis. Then its E plane is the xoz plane, which is set in the HFSS simulation as: θ = 0°-360°, The H plane is the yoz plane, and in the HFSS simulation, it is set as: θ=0°-360°,

[0086] The second type: In recent years, antenna designs often use directional patterns with main polarization and cross polarization to comprehensively observe the quality of antenna radiation performance. Main polarization or coplanar polarization refers to the polarization desired for antenna radiation. Cross polarization is perpendicular to the main polarization and is the polarization that is not desired for antenna radiation. The smaller the value, the better. For a perfect antenna polarization characteristic, cross polarization should be equal to 0. However, due to the influence of ground conditions, atmospheric conditions, etc. on the polarization characteristics, the cross polarization of the antenna is not 0. Therefore, the ratio of main polarization to cross polarization is used to characterize the degree of radiation concentration. The larger the ratio, the more concentrated the antenna radiation is in the desired radiation direction. In HFSS simulation, the first thing to do is to determine the maximum radiation direction of the electric field. For linearly polarized antennas, the main settings are Gain Thcta and Gain Phi, and then the main polarization and cross polarization directional patterns of the antenna are generated.

[0087] Bandwidth:

[0088] Antenna bandwidth refers to the antenna voltage standing wave ratio (VSWR), return loss (S 11 ) and other parameters do not exceed the allowable values. For example, general antenna design requirements are VSWR less than 1.5 and return loss greater than 10dB. The antenna bandwidth is the frequency band that meets these conditions.

[0089] The bandwidth of an antenna can be expressed in two forms: absolute bandwidth and relative bandwidth.

[0090] The absolute bandwidth △f can be calculated by the following formula: △f=fh -f l ; Among them, f h To meet the upper frequency limit of certain performance requirements, f l The lower frequency limit to meet certain performance requirements.

[0091] The relative bandwidth B can be calculated using the following formula:

[0092]

[0093] Where, f h To meet the upper frequency limit of certain performance requirements, f l To meet the lower frequency limit of certain performance requirements, f o is the center frequency.

[0094] Polarization:

[0095] The polarization of an antenna generally refers to the direction of the electric field. Polarization is categorized based on the trajectory of the electric field vector. If the electric field vector moves along a straight line in space, it's linear polarization; if it moves along a circle, it's circular polarization; and if it moves along an elliptical spiral, it's elliptical polarization. Linear polarization can be further divided into horizontal polarization and vertical polarization. If the electric field of a linearly polarized antenna is parallel to the ground, it's horizontally polarized; if the electric field of a linearly polarized antenna is perpendicular to the ground, it's vertically polarized.

[0096] Circular polarization can be further divided into left-hand circular polarization and right-hand circular polarization. When looking from the transmitting source to the receiving source, if the direction of movement of the electric field vector is counterclockwise, it is left-hand circular polarization, and vice versa.

[0097] In the HFSS software, the antenna's polarization gain diagram is obtained by selecting both RHCP Gain and LHCP Gain in the Far Field interface, selecting dB as the unit, selecting the viewing plane (xoz or yoz plane), and selecting the antenna's operating frequency. If RHCP Gain is larger than LHCP Gain, it indicates right-hand circular polarization; otherwise, it indicates left-hand circular polarization. If RHCP Gain and LHC Gain are almost the same, it indicates linear polarization.

[0098] This embodiment provides a board-mounted antenna, which is arranged on a substrate and includes a feeder, a first radiator and a parasitic ground unit. The feeder, the first radiator and the parasitic ground unit are all arranged in a clear area of the substrate to form a first antenna.

[0099] This embodiment utilizes a feeder line, a first radiator, and a parasitic ground unit disposed in a clear area of the substrate to form a first antenna, which can achieve a high-performance antenna structure without increasing the substrate area, thereby facilitating miniaturization of electronic devices.

[0100] In an optional embodiment, the onboard antenna further includes a second radiator. The feeder, the second radiator, and the ground plane of the substrate form the second antenna, and the parasitic ground unit is connected to the ground plane. In this embodiment, the onboard antenna includes a first antenna and a second antenna. By sharing the feeder and the clearance area, space for the first and second antennas within the substrate can be reduced, thereby meeting the requirements of a wide range of operating frequencies despite limited substrate space.

[0101] In an optional embodiment, the first radiator and the second radiator share a portion of the radiator, and the portion not shared by the first radiator and the second radiator is separated by a gap.

[0102] In an optional implementation manner, the frequency band of the first antenna is higher than the frequency band of the second antenna.

[0103] In an optional implementation manner, the length of the first radiator is consistent with the length of the parasitic ground unit. Accordingly, in this case, the transceiver conversion efficiency of the first antenna is the highest.

[0104] In an optional embodiment, at least one first slot is formed between the first radiator and the parasitic ground unit, and the width of the first slot is related to the electrical performance of the first antenna, and the electrical performance of the first antenna improves as the width of the first slot increases.

[0105] In an optional embodiment, the volume of the clearance area is related to the electrical performance of the first antenna, and the electrical performance of the first antenna improves as the volume of the clearance area increases. In other words, the larger the volume of the clearance area, the better the electrical performance of the first antenna. The electrical performance includes impedance, gain, bandwidth, etc.

[0106] In an optional embodiment, the parasitic ground unit includes at least two parasites, the length direction of some parasites is perpendicular to the length direction of the substrate, and the length direction of some parasites is parallel to the length direction of the substrate. This can reduce the length of the first antenna and save space on the substrate.

[0107] In an optional embodiment, the length direction of part of the second radiator is perpendicular to the length direction of the substrate, and the length direction of part of the second radiator is parallel to the length direction of the substrate, which can reduce the length of the second antenna and save space on the substrate.

[0108] In an optional embodiment, in a portion of the second radiator perpendicular to the length of the substrate, the minimum distance from the ground plane is positively correlated with the impedance of the second antenna. In this embodiment, the minimum distance is the height of the second antenna. The lower the height of the second antenna, the lower the impedance of the second antenna, and the higher the height of the second antenna, the greater the impedance of the second antenna.

[0109] In an optional embodiment, the length direction of part of the second radiator is parallel to the length direction of part of the first radiator, which can reduce the space occupied by the first antenna and the second antenna on the substrate, and improve the antenna's transceiver conversion efficiency by increasing the length of the first radiator and the second radiator as much as possible to meet 1 / 4 of the radio signal wavelength.

[0110] In an optional embodiment, the length of the second radiator is consistent with the length of the ground plane. Accordingly, in this case, the transceiver conversion efficiency of the second antenna is the highest.

[0111] In an optional embodiment, at least one second slot is formed between the second radiator and the parasitic ground unit. The width of the second slot is related to the electrical performance of the second antenna, and the electrical performance of the second antenna improves as the width of the second slot increases. In this embodiment, the electrical performance of the second antenna can be adjusted by adjusting the width of any second slot. Specifically, increasing the width of the second slot can improve the electrical performance of the second antenna.

[0112] In an optional embodiment, the volume of the clearance area is related to the electrical performance of the second antenna, and the electrical performance of the second antenna improves as the volume of the clearance area increases. In other words, the larger the volume of the clearance area, the better the electrical performance of the second antenna. The electrical performance includes impedance, gain, bandwidth, etc.

[0113] In an optional embodiment, the onboard antenna further includes an antenna matching component, and the second radiator is electrically connected to the ground plane via an inductor in the antenna matching component, thereby increasing the impedance of the second antenna.

[0114] It should be noted that the primary function of antenna matching components is to optimize the antenna's impedance characteristics to match the impedance of the RF front-end circuit (such as the transmitter or receiver), thereby reducing reflection loss and improving energy transmission efficiency. In practice, antenna matching components may include not only inductors but also capacitors, filters, and other components.

[0115] In an optional embodiment, the first radiator includes a target segment radiator and a first segment radiator, and the second radiator includes the target segment radiator and a second segment radiator, the target segment radiator being connected to the first segment radiator, and the target segment radiator being connected to the second segment radiator via an inductor. In this embodiment, the first and second radiators share the target segment radiator, and the target segment radiator is connected to the second segment radiator via an inductor, thereby increasing the impedance of the second antenna.

[0116] In an optional embodiment, the ground pin of the antenna matching component is connected to a first ground pad provided on the substrate.

[0117] In an optional embodiment, the ground plane includes a first ground copper foil, the first ground copper foil and the antenna matching component are located on the same layer of the substrate, and the first ground copper foil is connected to the first ground pad.

[0118] In an optional embodiment, the ground plane further includes a second ground copper foil, the second ground copper foil and the first ground copper foil are located on different layers of the substrate, and the second ground copper foil is connected to the first ground pad through a first ground via.

[0119] This embodiment also provides an electronic device including the above-mentioned onboard antenna. In specific implementations, the electronic device can be various electronic products, communication equipment, medical equipment, vehicle-mounted equipment, industrial equipment, mining equipment, etc., and is particularly suitable for wireless network equipment such as routers, vehicle-mounted equipment, and portable electronic devices.

[0120] In an optional embodiment, the electronic device includes a radio frequency component provided on the substrate, and a ground pin of the radio frequency component is connected to a second ground pad provided on the substrate.

[0121] In an optional embodiment, the ground plane of the substrate includes a third ground copper foil, the third ground copper foil and the RF component are located on the same layer of the substrate, and the third ground copper foil is connected to the second ground pad.

[0122] In an optional embodiment, the ground plane further includes a fourth ground copper foil, the fourth ground copper foil and the third ground copper foil are located on different layers of the substrate, and the fourth ground copper foil is connected to the second ground pad through a second ground via.

[0123] The following describes in detail the example where the onboard antenna corresponds to an onboard multi-band monopole microstrip antenna, the first antenna corresponds to a medium-high frequency antenna, and the second antenna corresponds to a low-frequency antenna.

[0124] Figure 1 A top view of a board-mounted multi-frequency antenna on a PCB is given. Figure 2 A partial top view of a board-mounted multi-frequency antenna on a PCB is given. Figure 1 and Figure 2 As shown, the onboard multi-band monopole microstrip antenna 35 is applied to the LTE antenna. The onboard multi-band monopole microstrip antenna 35 is set at the end of the PCB board 103 (along the -Z direction). The onboard multi-band monopole microstrip antenna 35 includes a radiation unit 33, a parasitic ground unit 88 and a clearance area 34. The radiation unit 33 is composed of two parts: a medium-high frequency radiator 89 and a low-frequency radiator 87. A parasitic ground line 83 is drawn out from the left side of the back position of the bottom end of the ground copper foil G5. The parasitic ground line 83 is directly connected to the ground copper foil G5 in the PCB board 103. The parasitic ground line 83 is connected to the parasitic ground unit 88. The parasitic ground unit 88 is The shape is distributed and distributed on the left side of the clearance area 34, that is, The parasitic ground unit 88 is distributed on the board edge of the clearance area 34 in the -X direction; The shaped parasitic ground unit 88 consists of a parasitic ground line 83, a starting parasitic body 94, a first middle parasitic body 95, a second middle parasitic body 96, and a terminal parasitic body 97. The starting parasitic body 94 is connected to the parasitic ground line 83 and then connected to the first middle parasitic body 95 after being rotated 90 degrees to the left by the starting parasitic body 94. The starting parasitic body 94 and the parasitic ground line 83 are perpendicular to the short side of the ground copper foil G5 in the PCB board 103 in the Z direction. That is, the starting parasitic body 94 and the parasitic ground line 83 are aligned with the long side A3 of the PCB board 103. The first middle parasitic body 95 is perpendicular to the starting parasitic body 94, that is, the short side of the ground copper foil G5 in the PCB board 103 is aligned. The inscribed angle at the connection between the starting parasite 94 and the first mid-end parasite 95 is 90 degrees. This means the inscribed angle between the starting parasite 94 and the first mid-end parasite 95 is a right angle, while the circumscribed angle between the starting parasite 94 and the first mid-end parasite 95 is a circular arc. The first mid-end parasite 95 is rotated 90 degrees in the -Z direction to connect with the second mid-end parasite 96. This means the first mid-end parasite 95 and the second mid-end parasite 96 are connected at a 90-degree angle, with the inscribed and circumscribed angles between them being 90 degrees. The second mid-end parasite 96 is located near the left edge of the PCB 103. The second mid-end parasitic body 96 is rotated 90 degrees in the X direction and connected to the terminal parasitic body 97. That is, the second mid-end parasitic body 96 is connected to the terminal parasitic body 97 at a 90-degree angle, and the inscribed angle and circumscribed angle between them are distributed at 90 degrees. The terminal parasitic body 97 is parallel to the short side direction B3 of the PCB board 103 and is aligned with the short side direction of the ground copper foil G5 in the PCB board 103. A ground via 205 is provided on the ground copper foil G5 in the PCB board 103 at the location where it connects to the parasitic ground line 83. The ground via 205 is used to connect the ground copper foil G5 in the PCB board 103. The ground copper foil G5 includes each layer of ground copper foil in the PCB board 103. The parasitic ground units 88 are all distributed in the clearance area 34.

[0125] Figure 3 This paper presents a method for connecting the parasitic ground and the copper foil of a two-layer PCB. It also shows a cross-sectional view of the PCB and the multi-band monopole microstrip antenna along the -Z to Z direction. Figure 4 A cross-sectional view of a two-layer PCB board and an onboard multi-band monopole microstrip antenna along the -X to X direction is given. Figure 5 This paper presents an alternative method for connecting the parasitic ground to the copper foil of a two-layer PCB. It also shows a cross-sectional view of the PCB and the multi-band monopole microstrip antenna along the -Z to Z direction. Figure 6 This paper presents a method for connecting the parasitic ground and the copper foil of a four-layer PCB. It also shows a cross-sectional view of the PCB and the multi-band monopole microstrip antenna along the -Z to Z direction. Figure 7 A cross-sectional view of a 4-layer PCB board and an onboard multi-band monopole microstrip antenna along the -X to X direction is given. Figure 8 Another cross-sectional view of a four-layer PCB and its multi-band monopole microstrip antenna along the -X to X direction is shown. Ground vias 205 are distributed within the ground copper foil G5 region of PCB 103. This region houses RF components (e.g., LTE modules, Wi-Fi modules, Bluetooth modules, etc.), power supply components (e.g., LDOs, buck power supplies, boost power supplies, etc.), MCU components, flash components, and a GPS module baseband.

[0126] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 5As shown, an RF chip 202 (which can also be an RF module) is provided on the L01 layer of the PCB board 103. The RF chip 202 includes an RF pin 50, a ground pin 53, etc. The L01 layer (i.e., the TOP layer) or the L04 layer (i.e., the BOT layer) of the PCB board 103 includes an RF pad 52 and a ground pad 51. The RF pin 50 is electrically connected to the RF pad 52 of the L01 layer of the PCB board 103 via solder, and the ground pin 53 is electrically connected to the ground pad 51 of the L01 layer of the PCB board 103 via solder. Ground vias 54 are provided near the ground pad 51 of the L01 layer, wherein the number of ground vias 54 is greater than or equal to 1. Ground pad 51 is electrically connected to ground via 54. If ground via 54 is a blind via (e.g., a laser blind via or a mechanical blind via), the blind via can be set directly on ground pad 51. This minimizes the ground impedance from ground pad 51 to ground copper foil G52 on layer L02, thereby improving the ground impedance from RF chip 202 to the entire board ground copper foil. Ground pin 53, located on layer L01 of PCB 103, is directly electrically connected to ground copper foil G51 on layer L01, further reducing the ground impedance from RF chip 202 to the entire board ground copper foil. Signal trace 70 is also provided near RF chip 202 on layer L01. An RF trace 203 is drawn from the RF pad 52 of the L01 layer. One end of the RF trace 203 is electrically connected to the RF pad 52. The other end of the RF trace 203 is electrically connected to one end of the antenna matching component 201. The other end of the antenna matching component 201 is electrically connected to the feed line 84 through the RF trace 200. Figure 3 、 Figure 5 PCB board 103 is a two-layer board. The projection of RF chip 202, RF trace 203, antenna matching component 201, and RF trace 200 on layer L02 of PCB board 103 is a complete ground copper foil G52. The projection of parasitic ground line 83, starting parasitic 94, first mid-end parasitic 95, second mid-end parasitic 96, and end parasitic 97 on layer L02 of PCB board 103 is a copper-free area, that is, clearance area 34. Within clearance area 34, except for parasitic ground unit 88 and mid-high frequency radiator 89 and low frequency radiator 87, which contain a small amount of metal, clearance area 34 is basically a copper-free area, providing a good environment for the onboard multi-band monopole microstrip antenna 35 to generate radio electromagnetic waves.

[0127] Figure 4 and Figure 3 The difference is that in Figure 4 In the figure, the RF chip 202 of the L01 layer is projected onto the ground copper foil G52 of the L02 layer and a signal trace 71 is provided. The rest are the same and will not be described again.

[0128] Figure 6 and Figure 4 The difference is that Figure 6The PCB board 103 in the figure is a 4-layer board. Figure 4 Two signal layers are added on the basis of the middle two-layer board, and L03 layer and L04 layer are added in the -Y direction of the ground copper foil G52 of the L02 layer respectively to form a four-layer board. Ground copper foil G53 is set on the L03 layer, and signal trace 71 is also set on the ground copper foil G53. Ground copper foil G54 is set on the L04 layer, and signal trace 71 is also set on the ground copper foil G54. The rest are the same and will not be repeated.

[0129] Figure 6 、 Figure 7 、 Figure 8 It is a 4-layer board, and Figure 5 It is a two-layer board. Figure 5 yes Figure 1 、 Figure 2 、 Figure 3 A cross-sectional view of the medium and high frequency radiator 89 along the 2-layer board in the -X to X direction; Figure 7 yes Figure 1 、 Figure 2 、 Figure 6 A cross-sectional view of the medium and high frequency radiator 89 along the 4-layer board in the -X to X direction; Figure 8 yes Figure 1 、 Figure 2 、 Figure 6 The low-frequency radiator 87 is a cross-sectional view along the 4-layer board from -X to X direction.

[0130] The RF component 202 is a RF circuit component composed of an RF chip. The ground pin 53, ground pad 51, ground via 54 of the RF component 202, the ground pin 57, ground pad 58, ground via 56, and parasitic ground unit 88 of the antenna matching component 201 are electrically connected through the ground copper foil G5. In this way, the ground pin 53 of the RF component 202, the ground pin 57 of the antenna matching component 201, the ground copper foil G5, and the parasitic ground unit 88 can form a complete ground return path for the transmission of the RF signal.

[0131] Lead out the feed line 84 from the right side (i.e., X direction) of the back side of the bottom end of the ground copper foil G5 in the PCB board 103 and extend along the -Z direction of the PCB board. The feed line 84 is electrically connected to the radiation unit 33. The shaped gap separates radiating element 33 into a mid-high frequency radiator 89 and a low frequency radiator 87. The mid-high frequency radiator 89, the clearance area 34, and the parasitic ground element 88 form a mid-high frequency antenna, while the low frequency radiator 87, the clearance area 34, and the copper foil G5 on the PCB board 103 form a low frequency antenna. Both the mid-high frequency antenna and the low frequency antenna are monopole microstrip antennas.

[0132] The medium and high frequency radiator 89 is The mid-high frequency radiator 89 is distributed in a zigzag pattern. It consists of a target segment radiator 93, a mid-end radiator 98, and a terminal radiator 99. One end of the mid-end radiator 98 is connected to the feed line 84 along the Z direction, and the other end of the mid-end radiator 98 is connected to the terminal radiator 99 along the Z direction. The terminal radiator 99 is distributed along the X direction, that is, the terminal radiator 99 intersects the target segment radiator 93 and the mid-end radiator 98 perpendicularly, that is, the terminal radiator 99 intersects the Z direction perpendicularly. The mid-high frequency radiator 89, the parasitic ground unit 88, and the clearance area 34 form the mid-high frequency antenna 300.

[0133] In a specific implementation, the length of the medium and high frequency radiator 89 can be one-quarter of the wavelength of the radio signal. The voltage standing wave ratio of the medium and high frequency antenna 300 composed of the medium and high frequency radiator 89 and the parasitic ground unit 88 is less than 2, and the return loss of the medium and high frequency antenna 300 is less than -10dB, so as to ensure that the medium and high frequency antenna 300 has good performance parameters.

[0134] When the length of the IF antenna 300 is 1 / 4 of the wavelength of the radio signal, the transmission and reception conversion efficiency of the IF antenna 300 is the highest, and it can be adjusted to the resonant state of the IF antenna 300, and the IF antenna 300 can be easily matched with the RF trace 204, the antenna matching component 201 and the RF module 202. Therefore, the length L12 of the IF radiator 89 in the IF antenna 300 will be determined according to the frequency, i.e., the wavelength, of the transmitted and received signals. As long as the corresponding center frequency of transmission and reception is known, the wavelength of the corresponding radio signal can be calculated, and then the calculated wavelength divided by 4 is the optimal length of the corresponding IF radiator 89. Among them, the conversion formula between frequency and wavelength is: wavelength = 300,000 kilometers / frequency = 300,000,000 meters / frequency. Specifically in this embodiment, as Figure 2 As shown, the resonant length L12 of the mid-high frequency radiator 89 is the sum of the length L2 of the feeder line 84, the length L1 of the target segment radiator 93, the length L3 of the mid-end radiator 98, and the length L11 of the terminal radiator 99, which is approximately equal to 1 / 4 wavelength. Adjusting the length L2 of the feeder line 84, the length L1 of the target segment radiator 93, the length L3 of the mid-end radiator 98, and the length L4 of the terminal radiator 99 will affect the resonant point of the mid-high frequency antenna 300. In other words, adjusting the length L12 of the mid-high frequency radiator 89 will affect the resonant frequency of the mid-high frequency antenna 300. Considering that the dielectric constant of the PCB board 103 also affects the resonant frequency of the mid-high frequency antenna 300, it is generally slightly smaller than the calculated data of 1 / 4 wavelength.

[0135] The HF radiator 89 is equivalent to the positive oscillator of the HF antenna 300. The parasitic ground unit 88 is equivalent to the negative dipole of the medium and high frequency antenna 300. Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 6 As shown, The length of the parasitic ground unit 88 is formed by the superposition of the length of the starting parasitic body 94, the length of the first middle parasitic body 95, the length of the second middle parasitic body 96, and the length of the terminal parasitic body 97. When the length of the parasitic ground unit 88 is also required to meet the 1 / 4 wavelength of the radio signal, considering the dielectric constant of the PCB board 103 The resonant frequency of the parasitic ground unit 88 is also affected and is generally slightly smaller than the calculated 1 / 4 wavelength data.

[0136] The ground copper foil G5 is perpendicular to the first middle parasitic element 95 and the end parasitic element 97 of the parasitic ground unit 88 in the longitudinal direction. The ground copper foil G5 is also parallel to the parasitic ground line 83, the starting parasitic element 94, and the second middle parasitic element 96 in the parasitic ground unit 88 in the same vertical direction from Z to -Z. The ground copper foil G5 maintains the same longitudinal direction as the PCB.

[0137] like Figure 2 As shown, the first end of the feed line 84 is connected to the RF trace 204 distributed in the ground copper foil G5 area. The feed line 84 is distributed along the -Z direction in the clearance area 34. The feed line 84 can be designed to have the same width as the RF trace 204 in the ground copper foil G5 area. The RF trace 204 in the ground copper foil G5 area has a reference ground copper foil of an adjacent layer (e.g. Figure 3 The ground copper foil G52 in the L02 layer of the middle 2-layer board and the reference ground copper foil of the adjacent layer of the same layer (for example Figure 3 The ground copper foil G51 in the middle 2-layer board L02, therefore, the impedance of the RF trace 204 in the ground copper foil G5 area is controllable, generally designed to be 50 ohms ± 5 ohms or 75 ohms ± 7.5 ohms. However, since the feed line 84 falls within the clearance area 34, its impedance is not controllable and is generally classified as part of the radiator of the medium-high frequency antenna 300 or the low-frequency antenna 301. Figure 2 As shown, the track direction of the feed line 84 and the RF trace 204 in the ground copper foil G5 area are basically distributed from the Z direction along the -Z direction. Of course, the RF trace 204 in the ground copper foil G5 area is not necessarily distributed along the -Z direction in the Z direction, and can also be distributed at other angles. The shape and direction of the RF trace 204 in the ground copper foil G5 area are not limited.

[0138] The target segment radiator 93 is distributed in the clearance area 34. The first end of the target segment radiator 93 is connected to the second end of the feed line 84, and the second end of the target segment radiator 93 is connected to the second end of the middle radiator 98. The target segment radiator 93 is distributed along the second end of the feed line 84 from the Z direction to the -Z direction. The second end of the target segment radiator 93 is connected to the first end of the middle radiator 98 at the intersection of the -X direction and the -Z direction, and the second end of the target segment radiator 93 is connected to the low-frequency radiator 87 along the X direction, wherein the target segment radiator 93 is specifically connected to the third segment radiator 90 in the low-frequency radiator 87. Since the width of the target segment radiator 93 is greater than the width of the feed line 84, the transition section between the target segment radiator 93 and the feed line 84 is The shape distribution, the transition section between them is connected at right angles, and can also be distributed in a "▲" gradient, and the shape of the transition section between the target segment radiator 93 and the feeder 84 is not limited. The first end of the middle radiator 98 protrudes at a right angle to the second end of the target segment radiator 93 in the -X direction, that is, the width of the first end of the middle radiator 98 is wider than the width of the second end of the target segment radiator 93. It extends along the -Z direction of the first end of the middle radiator 98 to the second end of the middle radiator 98, and the width of the second end of the middle radiator 98 is the same as the width of the first end of the middle radiator 98. The end radiator 99 is set at the second end of the middle radiator 98 along the X direction. The second end of the middle radiator 98 is connected to the first end of the end radiator 99, and the second end of the end radiator 99 is suspended in the air. The middle radiator 98 is connected to the end radiator 99 at a right angle.

[0139] The length L12 of the medium and high frequency radiator 89 is the sum of the length L2 of the feeder 84, the length L1 of the target segment radiator 93, the length L3 of the middle radiator 98, and the length L11 of the end radiator 99: L12 = L2 + L1 + L3 + L11.

[0140] like Figure 2 、 Figure 6 、 Figure 7As shown, an on-board multi-band RF module 202 (e.g., an LTE module) is provided in the ground copper foil G5 of the L01 layer of the PCB board 103. The RF pin 52 of the on-board multi-band RF module 202 is electrically connected to the RF pad 50 through soldering. The RF trace 203 is led out from the RF pad 50 and electrically connected to the antenna matching component 201. The RF trace 200 is then led out from the antenna matching component 201 and electrically connected to the feeder 84, the target segment radiator 93, the mid-end radiator 98, and the end radiator 99. The ground pin 53 of the onboard multi-band RF module 202 is electrically connected to the ground pad 51 through solder, and the ground pad 51 is electrically connected to the ground copper foil G5: the ground pad 51 is directly electrically connected to the ground copper foil G51 of the L01 layer, and multiple ground vias 54 are set near the ground pad 51. The ground vias 54 are electrically connected to the ground copper foil G51 of the L01 layer, the ground copper foil G52 of the L02 layer, the ground copper foil G53 of the L03 layer, and the ground copper foil G54 of the L04 layer. In other words, an electrically connected RF path is formed from the RF pin 52 of the onboard multi-band RF module 202, the RF pad 50, the RF trace 203, the antenna matching component 201, the RF trace 200 to the medium and high frequency radiator 89. The parasitic ground unit 88 is electrically connected via a parasitic ground line 83. Multiple ground vias 55 are provided within the ground copper foil G5 region and near the parasitic ground line 83. These ground vias 55 electrically connect the parasitic ground line 83, the ground copper foil G51 on the L01 layer, the ground copper foil G52 on the L02 layer, the ground copper foil G53 on the L03 layer, and the ground copper foil G54 on the L04 layer into a low-impedance ground connection. An electrically connected return ground path is formed from the ground pin 53, ground pad 51, and ground copper foil G51 of the onboard multi-band RF module 202 to the parasitic ground unit 88.

[0141] The onboard multi-band RF module 202 generates a medium-high frequency RF signal (e.g., LTE RF 2.0GHz to 2.7GHz), which is injected into the feeder 84, the target segment radiator 93, the middle radiator 98, and the end radiator 99 through the RF pin 52, the RF pad 50, the RF trace 203, the antenna matching component 201, and the RF trace 200, generating medium-high frequency resonance. The medium-high frequency radiator 89 and the parasitic ground unit 88 in the clearance area generate displacement current, forming a medium-high frequency pulse electromagnetic field, which is directed away from the medium-high frequency radiator 89 and the parasitic ground unit 88. The -Z direction of the parasitic ground unit 88, the Y direction perpendicular to the PCB board 103, and the -Y direction generate external radiation, increasing the angle and range of the external radiation of the medium and high frequency antenna 300, that is, it has strong directivity in the three directions of -Z direction, Y direction and -Y direction. The radiation in the -Z direction is horizontally polarized, while the radiation in the -Z direction and -Y direction is vertically polarized. This is a typical directional radiation characteristic, that is, the medium and high frequency antenna 300 composed of the medium and high frequency radiator 89, the ground copper foil G5, and the parasitic ground unit 88 is a typical directional radiation antenna.

[0142] The medium and high frequency radiator 89 and Slots 40 are formed between the parasitic ground elements 88. Specifically, the copper-free area between feeder line 84 and parasitic ground line 83 is slot 4, the copper-free area between target segment radiator 93 and starting parasitic 94 is slot 47, the copper-free areas between first mid-end parasitic 95, second mid-end parasitic 96, end parasitic 97, and mid-end radiator 98 are slots 85 and 41, and the copper-free area between end parasitic 97 and sixth segment radiator 57 is slot 42. The width of slot 42 between end parasitic 97 and sixth segment radiator 57 is W1. The parasitic ground unit 88 is electrically connected to the ground copper foil G5 in the substrate 103 through the parasitic ground line 83. The medium and high frequency radiator 89 and The parasitic ground unit 88 forms the structure of the medium and high frequency antenna 300, which meets the performance of high efficiency and high gain in complex environments. The medium and high frequency radiator 89 and The width W5 of the slots 41 between the parasitic ground units 88 can fine-tune the gain and bandwidth of the mid-high frequency antenna 300 .

[0143] Adjustment The medium and high frequency radiator 89 and The width W5 of the slot 41 between the parasitic ground units 88 is adjusted to adjust the VSWR (Voltage Standing Wave Ratio) and VSWR (Voltage Standing Wave Ratio) performance of the mid-high frequency antenna 300. The medium and high frequency radiator 89 and The width W5 of the slot 41 between the parasitic ground units 88 can freely adjust the matching degree of the antenna impedance (that is, the coupling amount) between the upper and lower critical values of the characteristic impedance (for example, 50 ohms or 75 ohms), so that the medium and high frequency antenna 300 can achieve the optimal coupling state.

[0144] The shaped medium and high frequency radiator 89 is the positive oscillator of the medium and high frequency antenna 300, and The parasitic ground unit 88 is the negative dipole of the medium and high frequency antenna 300. The length of the parasitic ground unit 88 must be a quarter of the wavelength of the radio signal injected into the medium and high frequency antenna 300. The length and The length of the parasitic ground unit 88 is kept consistent, the transmission and reception conversion efficiency of the medium and high frequency antenna 300 is the highest, the medium and high frequency antenna 300 can be adjusted to the optimal resonant state, and the low frequency antenna 301 can be easily matched with the RF trace 204, the antenna matching component 201 and the RF module 202.

[0145] Continue to refer Figure 2 and Figure 7 The low-frequency radiator 87 is composed of the target segment radiator 93, the third segment radiator 90, the fourth segment radiator 91, the fifth segment radiator 92, and the sixth segment radiator 57. A third radiator 90 extends from the intersection of the target radiator 93 and the middle radiator 98 (i.e., the intersection of the second end of the target radiator 93 and the first end of the middle radiator 98) in the X direction. The first end of the third radiator 90 is connected to the target radiator 93 and the middle radiator 98 at a right angle. The first end of the third radiator 90 extends along the X direction of the PCB board 103 to the edge of the PCB board 103 (that is, extends to the left side of the PCB board 103). The second end of the third radiator 90 is rotated 90 degrees along the edge of the PCB board 103 in the X direction and connected to the first end of the fourth radiator 91. The first end of the fourth radiator 91 extends along the edge of the PCB board 103 in the X direction toward the -Z direction of the PCB board 103 to the second end of the fourth radiator 91 at the edge of the PCB board 103. The second end of the fourth radiator 91 is rotated 90 degrees along the edge of the PCB board 103 in the X direction and connected to the first end of the fifth radiator 92. The first end of the fifth radiator segment 92 extends along the X-direction edge of the PCB 103 in the -X direction to the second end of the fifth radiator segment 92. The first end to the second end of the fifth radiator segment 92 are located close to the -Z-direction edge of the PCB 103. The coordinate of the second end of the fifth radiator segment 92 in the -X direction is between the terminal parasitic element 97 and the middle radiator segment 98. The second end of the fifth radiator segment 92 is connected to the first end of the sixth radiator segment 57 in the -X direction. The second end of the sixth radiator segment 57 is suspended in the -X direction. The second end of the sixth radiator segment 57 extends along the -X direction of the PCB 103 to the extreme end of the low-frequency radiator 87. The first end to the second end of the sixth radiator segment 57 are located close to the -Z-direction edge of the PCB 103.

[0146] like Figure 2 、 Figure 6 、 Figure 8As shown, an onboard multi-band RF module 202 (e.g., an LTE module) is disposed within the ground copper foil G5 of layer L01 of PCB board 103. The RF pin 52 of onboard multi-band RF module 202 is electrically connected to the RF pad 50 via solder. An RF trace 203 is led from the RF pad 50 and electrically connected to the antenna matching assembly 201. An RF trace 200 is then led from the antenna matching assembly 201 and electrically connected to the feeder 84, target segment radiator 93, third segment radiator 90, fourth segment radiator 91, fifth segment radiator 92, and sixth segment radiator 57. An electrically connected RF path is formed from the RF pin 52 of onboard multi-band RF module 202, the RF pad 50, the RF trace 203, the antenna matching assembly 201, and the RF trace 200 to the low-frequency radiator 87.

[0147] The ground pin 53 of the onboard multi-band RF module 202 is electrically connected to the ground pad 51 via solder, and the ground pad 51 is electrically connected to the ground copper foil G5: the ground pad 51 is directly electrically connected to the ground copper foil G51 of the L01 layer, and multiple ground vias 54 are provided near the ground pad 51. The ground vias 54 are electrically connected to the ground copper foil G51 of the L01 layer, the ground copper foil G52 of the L02 layer, the ground copper foil G53 of the L03 layer, and the ground copper foil G54 of the L04 layer. The ground pad 51, the ground pad 51, the multiple ground vias 54, and the ground copper foil G5 form a low-impedance grounding entity. An electrically connected return ground path is formed from the ground pin 53, the ground pad 51, and the ground copper foil G5 of the onboard multi-band RF module 202. The low-frequency antenna 301 is composed of the low-frequency radiator 87, the ground copper foil G5, and the clearance area 34.

[0148] The onboard multi-band RF module 202 generates a low-frequency RF signal, such as 703MHz to 960MHz of LTE RF, which is injected into the feeder 84, the third radiator 90, the fourth radiator 91, the fifth radiator 92, and the sixth radiator 57 through the RF pin 52, the RF pad 50, the RF trace 203, the antenna matching component 201, and the RF trace 200, generating low-frequency resonance. The low-frequency radiator 87 in the clear area and the ground copper foil G5 generate displacement current, forming a low-frequency pulsed electromagnetic field, which is directed away from the low-frequency radiator. The radiator 87 and the ground copper foil G5 generate outward radiation in the -Z direction, the Y direction perpendicular to the PCB board 103, and the -Y direction, thereby increasing the angle and range of the outward radiation of the low-frequency antenna 301. That is, the antenna has strong directivity in the three directions of -Z, Y, and -Y. The radiation in the -Z direction is horizontally polarized, while the radiation in the -Z and -Y directions is vertically polarized. This is a typical characteristic of directional radiation, that is, the low-frequency antenna 301, the ground copper foil G5, and the ground copper foil G5 are composed of a typical directional radiation antenna.

[0149] In a specific implementation, the length of the low-frequency radiator 87 can be one-quarter of the wavelength of the radio signal. The voltage standing wave ratio of the low-frequency antenna 301 formed by the low-frequency radiator 87 and the ground copper foil G5 is less than 2, and the return loss of the low-frequency antenna 301 is less than -10dB, so as to ensure that the low-frequency antenna 301 has good performance parameters.

[0150] When the length of the low-frequency antenna 301 is 1 / 4 of the wavelength of the radio signal, the transmission and reception conversion efficiency of the low-frequency antenna 301 is the highest, the low-frequency antenna 300 can be adjusted to the optimal resonant state, and the low-frequency antenna 301 can be easily matched with the RF trace 204, the antenna matching component 201 and the RF module 202. Therefore, the length L13 of the low-frequency radiator 87 in the low-frequency antenna 301 will be determined according to the frequency, i.e., the wavelength, of the transmitted and received signals. As long as the corresponding center frequency of the transmission and reception is known, the wavelength of the corresponding radio signal can be calculated, and then the calculated wavelength divided by 4 is the optimal length of the corresponding low-frequency radiator 87. Among them, the conversion formula between frequency and wavelength is: wavelength = 300,000 kilometers / frequency = 300,000,000 meters / frequency. Specifically in this embodiment, if Figure 2 As shown, the resonant length L13 of the low-frequency radiator 87 is the sum of the length L2 of the feeder line 84, the length L1 of the target radiator 93, the length L5 of the third radiator 90, the length L6 of the fourth radiator 91, the length L8 of the fifth radiator 92, and the length L10 of the sixth radiator 57, which is approximately equal to 1 / 4 wavelength. Adjusting the length L2 of the feeder line 84, the length L1 of the target radiator 93, the length L5 of the third radiator 90, the length L6 of the fourth radiator 91, the length L8 of the fifth radiator 92, and the length L10 of the sixth radiator 57 will affect the resonant point of the low-frequency antenna 301. In other words, adjusting the length L13 of the low-frequency radiator 87 affects the resonant frequency of the low-frequency antenna 301. Considering that the dielectric constant of the PCB board 103 also affects the resonant frequency of the mid- and high-frequency antenna 300, it is generally slightly smaller than the calculated value of 1 / 4 wavelength.

[0151] The length L12 of the low-frequency radiator 87 is the sum of the length L2 of the feeder 84, the length L1 of the target segment radiator 93, the length L5 of the third segment radiator 90, the length L6 of the fourth segment radiator 91, the length L8 of the fifth segment radiator 92, and the length L10 of the sixth segment radiator 57: L13 = L2 + L1 + L5 + L6 + L8 + L10.

[0152] Both the mid-high frequency antenna 300 and the low frequency antenna 301 are microstrip monopole antennas, and their operating wavelengths can be calculated using the following formula:

[0153]

[0154] Where c represents the speed of light, c = 3x10 11 mm / s, f represents the operating frequency.

[0155] Both the mid-high frequency antenna 300 and the low frequency antenna 301 are microstrip monopole antennas, and their widths can be calculated using the following formula:

[0156]

[0157]

[0158] Where W is the width of the radiator, h is the thickness of the dielectric substrate. Zo is the characteristic impedance of the microstrip line, ε r is the relative permittivity of the dielectric substrate.

[0159] like Figure 1 As shown, the width of the mid-high frequency radiator 89 of the mid-high frequency antenna 300 is W7, and the width of the low frequency radiator 87 of the low frequency antenna 301 is W6.

[0160] The thickness h of the PCB board 103 (dielectric substrate) is set to 1.6 mm, Zo = 50 ohms and ε r =3.55 is substituted into formula (1) and formula (2) to obtain the width W7 of the medium and high frequency radiator 89 of the high frequency antenna 300 = 2.5 mm, and the width W6 of the low frequency radiator 87 of the low frequency antenna 301 = 2.5 mm.

[0161] Continue reading Figure 1 、 Figure 2 As shown, the length of the clearance area 34 along the -Z direction of the PCB board 103 is L7, and the length of the clearance area 34 along the X and -X directions of the PCB board 103 is L8. The product of L7 and L8 is the area of the clearance area 34, that is, the area of the near-field radiation area of the mid-high frequency antenna 300 and the low frequency antenna 301. The mid-high frequency antenna 300 and the low frequency antenna 301 share the clearance area 34, but because the operating frequency of the mid-high frequency antenna 300 is higher than that of the low frequency antenna 301, the area of the clearance area 34 has little effect on the mid-high frequency antenna 300, but has a very large impact on the low frequency antenna 301. The clearance area 34 must consider the reasonable length L13 of the low-frequency radiator 87 in the low-frequency antenna 301, the reasonable length L12 of the intermediate-high-frequency radiator 89 of the intermediate-high-frequency antenna 300, and the reasonable length of the parasitic ground unit 88. It is also necessary to consider the reasonable distance between the low-frequency radiator 87 in the low-frequency antenna 301 and the copper foil G5 on the PCB board 103, and the reasonable distance between the intermediate-high-frequency radiator 89 of the intermediate-high-frequency antenna 300 and the copper foil G5 on the PCB board 103. The size of the clearance area 34 directly affects the radiation efficiency of the intermediate-high-frequency antenna 300 and the low-frequency antenna 301, especially the radiation efficiency of the low-frequency antenna 301.

[0162] The relationship between the bandwidth and gain of the mid-high frequency antenna 300 and the low frequency antenna 301 and the clearance area 34 is: G (gain) B (bandwidth) is proportional to V (volume).

[0163] As can be seen from the above expression, the clearance area 34 should be increased to expand the bandwidth of the mid-high frequency antenna 300 and the low frequency antenna 301 without reducing the gain of the antenna. In other words, the ground copper foil G5 between the near-field sensing area of the mid-high frequency antenna 300 or the low frequency antenna 301 and the PCB board 103 will affect the volume of the antenna. Therefore, a large clearance area 34 must be reserved near the mid-high frequency antenna 300 or the low frequency antenna 301, and no metal parts must be included to meet the radiation space requirements of the near-field sensing area of the mid-high frequency antenna 300 or the low frequency antenna 301. In addition, the overall structure (such as the battery in the plastic shell) and the stacking (tall metal components on the PCB board 103, such as aluminum electrolytic capacitors and connectors) have a certain range of influence on the impedance, bandwidth, and gain of the mid-high frequency antenna 300 or the low frequency antenna 301.

[0164] The low-frequency radiator 87 is equivalent to the positive oscillator of the low-frequency antenna 301, while the ground copper foil G5 of the PCB board 103 is equivalent to the negative oscillator of the low-frequency antenna 301. In the Z direction of the PCB board 103, away from the clearance area 34, the ground copper foil G5 of the PCB board 103 is located. The length of the ground copper foil G5 in the Z direction and the -Z direction of the PCB board 103 is L13. The length L13 of the ground copper foil G5 is the length of the negative oscillator of the low-frequency antenna 301. It also needs to meet 1 / 4 of the wavelength of the radio signal. Considering the dielectric constant of the PCB board 103, the length of the ground copper foil G5 is L13. The resonant frequency of the parasitic ground element 88 is also affected. The length L13 of the ground copper foil G5 is generally slightly less than the calculated 1 / 4 wavelength. Since the feed line 84 and the ground copper foil G5 are not short-circuited, the low-frequency antenna 301 is an inverted-L monopole antenna.

[0165] The relationship between the low-frequency radiator 87 and the ground copper foil G5 is as follows: the distance between the low-frequency radiator 87 and the ground copper foil G5 is L21, and the distance L21 between the low-frequency radiator 87 and the ground copper foil G5 is the height of the low-frequency antenna 301 (that is, the distance between the antenna arm and the ground). The height L21 of the low-frequency antenna 301 directly affects the impedance of the low-frequency antenna 301. The smaller the height L21 of the low-frequency antenna 301, the greater the distributed capacitance from the low-frequency radiator 87 to the ground copper foil G5, the greater the capacitance effect, and the smaller the impedance of the low-frequency antenna 301. The larger the height L21 of the low-frequency antenna 301, the smaller the distributed capacitance from the low-frequency radiator 87 to the ground copper foil G5, the smaller the capacitance effect, and the greater the impedance of the low-frequency antenna 301.

[0166] When designing a product, space is limited, which will greatly compress the distance L21 between the low-frequency radiator 87 and the ground copper foil G5. The stronger the coupling between the low-frequency radiator 87 and the ground copper foil G5, the greater the distributed capacitance between the low-frequency radiator 87 and the ground copper foil G5, the greater the capacitance effect, and the smaller the impedance of the low-frequency antenna 301. An inductor 31 is set in the antenna matching component 201 close to the feeder 84, and one end of the inductor 31 is connected in parallel to the RF trace 200 (the RF trace 200 is electrically connected to the feeder 84), and the other end of the inductor 31 is connected to the ground copper foil G5. In other words, the antenna matching assembly 201 must include an inductor 31, which is connected in parallel to the RF trace 200 and the feeder 84. The low-frequency radiator 87 is electrically connected to the ground copper foil G5 via the inductor 31. This reduces the distributed capacitance of the low-frequency antenna 301 and increases its impedance. By adjusting the inductance of the inductor 31, the characteristic impedance of the low-frequency antenna 301 reaches a critical value, which means that the center point of the resonant frequency of the low-frequency antenna 301 is as close to 50 ohms or 75 ohms as possible. If the distance L21 between the low-frequency radiator 87 and the ground copper foil G5 is too large, the inductor 31 connected in parallel to the RF trace 200 can be removed, or the parameters of the inductor 31 can be adjusted to keep the center point of the resonant frequency of the low-frequency antenna 301 as close to 50 ohms or 75 ohms as possible. The antenna matching component 201 at least includes an inductor 31 for adjusting the impedance of the low-frequency antenna 301 so that the VSWR of the low-frequency antenna 301 is less than 2 and S11 is less than -10 dB.

[0167] like Figure 2 、 Figure 6 、 Figure 7 、 Figure 8 As shown, the RF trace 200 is connected in parallel to the ground copper foil G5 through the inductor 31. One end of the inductor 31 is electrically connected to the RF trace 200, and the other end of the inductor 31 is a pin 32, and the pin 32 of the inductor 31 is soldered to the ground pad 30. The ground pad 30 is directly electrically connected to the ground copper foil G51 of the L01 layer on the L01 layer. At the same time, at least one ground via 205 is provided on the ground copper foil G51 of the L01 layer near the ground pad 30. Through the ground via 205, the ground pad 30, the ground copper foil G51 of the L01 layer, the ground copper foil G52 of the L02 layer, the ground copper foil G53 of the L03 layer, and the ground copper foil G54 of the L04 layer are electrically connected to form a low-impedance grounding entity. Figure 6 、 Figure 7 、 Figure 8 Taking the 4-layer PCB board in FIG. 1 as an example, the ground copper foil G5 includes the ground copper foil G51 of the L01 layer, the ground copper foil G52 of the L02 layer, the ground copper foil G53 of the L03 layer, and the ground copper foil G54 of the L04 layer.

[0168] The ground copper foil G5 is perpendicular to the third radiator segment 90, the fifth radiator segment 92, and the sixth radiator segment 57 of the low-frequency radiator 87 in the longitudinal direction. The ground copper foil G5 is also parallel to the fourth radiator segment 91 and the target radiator segment 93 of the low-frequency radiator 87 in the longitudinal direction along the Z-to--Z direction. The ground copper foil G5 maintains the same longitudinal direction as the PCB.

[0169] Continue reading Figure 2 The third radiator segment 90 of the low-frequency radiator 87 and the terminal radiator 99 of the mid-high frequency radiator 89 are parallel to each other along the X-direction. A rectangular gap 86 separates the third radiator segment 90 of the low-frequency radiator 87 and the terminal radiator 99 of the mid-high frequency radiator 89. The rectangular gap 86 extends in the X-direction of the PCB 103. The terminal radiator 99 of the mid-high frequency radiator 89 also extends in the X-direction of the PCB 103. Therefore, the length L11 of the rectangular gap 86 is equal to the length L11 of the terminal radiator 99. The length L11 of the rectangular gap 86 is the distance from the left edge of the terminal radiator 99 of the mid-high frequency radiator 89 to the left edge of the terminal radiator 99 of the mid-high frequency radiator 89. The width W3 of the rectangular gap 86 is the distance from the lower edge of the third radiator segment 90 to the upper edge of the terminal radiator 99 of the mid-high frequency radiator 89.

[0170] The rectangular gap 44 formed between the terminal radiator 99 of the mid-high frequency radiator 89 and the third radiator segment 90, fourth radiator segment 91, and fifth radiator segment 92 of the low frequency radiator 87 has a length L22 and a width W4. The length L22 of the rectangular gap 44 is the distance from the right edge of the terminal radiator 99 of the mid-high frequency radiator 89 to the left edge of the fourth radiator segment 91 along the X direction of the PCB board 103. The width W4 of the rectangular gap 44 is the distance from the lower edge of the third radiator segment 90 to the upper edge of the fifth radiator segment 92 along the -Z direction of the PCB board 103. The fifth radiator 92 and the end radiator 99 in the medium and high frequency radiator 89 form a rectangular gap 43, the length of the rectangular gap 43 is L4, and the width of the rectangular gap 43 is W2, wherein the length L4 of the rectangular gap 43 is the distance from the right edge of the end radiator 99 in the medium and high frequency radiator 89 to the left edge of the fifth radiator 92; the width W2 of the rectangular gap 43 is the distance from the lower edge of the end radiator 99 in the medium and high frequency radiator 89 to the upper edge of the fifth radiator 92.

[0171] The terminal parasitic element 97 in the parasitic ground unit 88 must maintain a certain gap 42 with the sixth radiator segment 57. Otherwise, the pulsed electric field parameters of the low-frequency radiator 87 will be affected. The width of gap 42 is the distance between the lower edge of the terminal parasitic element 97 in the parasitic ground unit 88 and the upper edge of the sixth radiator segment 57. The length L10 of gap 42 is the distance between the left edge of the fifth radiator segment 92 and the left edge of the sixth radiator segment 57.

[0172] The terminal parasitic body 97 is adjacent to the middle radiator 98 and is separated by a gap 85 . The high-frequency radiator 89 is on the left side close to The parasitic ground unit 88 is shaped and separated by a gap 85. The medium and high frequency radiator 89 and the parasitic ground unit 88 are electromagnetically coupled with each other, resonating to form a displacement current E3. The resonant frequency after coupling between them is maintained at 2300MHz-2400MHz and 2570MHz-2620MHz, which corresponds to the LTE high frequency band operating frequency.

[0173] The low-frequency radiator 87 and the copper foil G6 of the entire board are electromagnetically coupled to each other, resonating to form a displacement current E2. The resonant frequency after coupling between them is maintained at 703MHz~960MHz, which corresponds to the operating frequency of the LTE low-frequency band. The low-frequency radiator 87 is the positive oscillator (radiation unit) of the low-frequency antenna 301 at a resonant frequency of 703 MHz to 960 MHz, and the copper foil G5 of the whole board is the negative oscillator (reflection unit) of the low-frequency antenna 301 at a resonant frequency of 703 MHz to 960 MHz. The reflective surface of the low-frequency radiator 87 is the ground copper foil G5. When the low-frequency antenna 301 resonates in the low-frequency band of 703MHz to 960MHz, The low-frequency radiator 87 is on the reflective surface of the copper foil G5 of the whole board. When the mid-high frequency antenna 300 resonates in the mid-frequency band of 1710M~2170MHz, The low-frequency radiator 87 of the shape only stays at the parasitic ground unit 88 on the reflection surface of the copper foil G6 of the whole board. That is, when the medium-high frequency antenna 300 resonates in the medium frequency band of 1GHz to 2.4GHz, the copper foil G5 does not work. When the medium-high frequency antenna 300 resonates in the high frequency band of 2300MHz to 2400MHz and 2570MHz to 2620MHz, The medium and high frequency radiator 89 and shaped parasitic ground unit 88, The low-frequency radiator 87 only stays on the ground copper foil G5 on the reflection surface of the whole ground copper foil G6, that is, when the high-frequency antenna 300 resonates in the 1GHz to 2.4GHz mid-frequency band, the ground copper foil G5 does not work.

[0174] By adjusting the position and pattern of the parasitic ground unit 88, The high frequency radiator 89 and the parasitic ground unit 88 are electromagnetically coupled to each other, generating a resonance of a certain frequency. The resonance of the low-frequency radiator 87 and the copper foil G6 of the entire board are combined, thereby increasing the bandwidth of the high-frequency antenna 300 at the resonant frequency.

[0175] The frequency bands of domestic all-network antennas are GSM900 / 1800, CDMA800, TD-A / F, WCDMA-B1 / B8, TDD-B38 / 39 / 40 / 41, and FDD-B1 / B3, corresponding to the frequency ranges of 825MHz to 960MHz, 1710MHz to 2170MHz, 2300MHz to 2400MHz, and 2570MHz to 2620MHz. These ranges can generally be covered by four resonances. Specifically, a dual-frequency resonance is formed to cover the 825MHz to 960MHz and 1710MHz to 2170MHz frequency ranges, while the 2300MHz to 2400MHz and 2570MHz to 2620MHz frequency ranges are generally achieved by generating a resonance between a radiator and a parasitic ground unit.

[0176] The low-frequency radiator 87 of the low-frequency antenna 301, the mid-high frequency radiator 89 of the mid-high frequency antenna 300, and the parasitic ground element 88 are placed in the same clear area 34, and the parasitic ground element 88 is separated from the low-frequency radiator 87. The target segment radiator 93 is a common component of the low-frequency radiator 87 and the mid-high frequency radiator 89. In other words, the mid-high frequency antenna 300 and the low-frequency antenna 301 share the target segment radiator 93. When the mid-high frequency radiator 89 becomes the positive element of the mid-high frequency antenna 300 and the parasitic ground element 88 becomes the negative element of the mid-high frequency antenna 300, they form an inverted L monopole antenna. When the low-frequency radiator 87 becomes the positive element of the low-frequency antenna 301 and the ground copper foil of the PCB board 103 becomes the negative element of the low-frequency antenna 301, they form an inverted L monopole antenna. The mid- and high-frequency antenna 300 radiates low frequencies between 703 MHz and 960 MHz, while the low-frequency antenna 301 radiates mid- and high-frequency frequencies between 1 GHz and 2.7 GHz. This antenna structure shares a common clearance area, significantly saving space for both the mid- and high-frequency antennas 300 and 301, while simultaneously meeting the operating frequency requirements of all three frequencies, delivering excellent performance.

[0177] Figure 9 The top view of another board-mounted multi-band antenna on the PCB is given. Figure 1 The difference is that Figure 9The target radiator 93 is disconnected from the third radiator 90. Pad 1 is provided on the target radiator 93, and pad 2 is provided on the second radiator 90. Pins 8 and 7 of the inductor 301 are soldered to pads 1 and 2, respectively. In other words, the target radiator 93 and the third radiator 90 are electrically connected via the inductor 301. As products become increasingly compact, the size of the PCB board 103 is shrinking, and the clearance area 34 left for the low-frequency antenna 301 and the mid-high-frequency antenna 300 is shrinking. Since the mid-high-frequency antenna 300 operates at a relatively high frequency (1000 MHz to 2700 MHz), while the low-frequency antenna 301 operates at a relatively low frequency (703 MHz to 960 MHz), the clearance area 34 of the same size has a much smaller impact on the gain and bandwidth of the mid-high-frequency antenna 300 than on the low-frequency antenna 301. Therefore, when the clearance area 34 is smaller, the distance L21 between the ground copper foil G5 and the low-frequency radiator 87 becomes smaller, resulting in an increase in the distributed capacitance of the low-frequency antenna 301, which affects the characteristic impedance of the low-frequency antenna 301. Therefore, the inductor 301 can be added between the target segment radiator 93 and the third segment radiator 90 to increase the characteristic impedance of the low-frequency antenna 301 to a critical value, and the center point of the resonant frequency of the low-frequency antenna 301 is as close to 50 ohms or 75 ohms as possible. The addition of the inductor 301 between the target segment radiator 93 and the third segment radiator 90 does not affect the center point of the resonant frequency of the mid-high frequency antenna 300. This allows both parameters to reach an optimal state.

[0178] PCB 103 is made of insulating material. The choice of material affects the loss tangent of the mid-high frequency antenna 300 and the low frequency antenna 301. A larger loss tangent indicates greater loss, which in turn increases the bandwidth of the mid-high frequency antenna 300 and the low frequency antenna 301, reducing radiation efficiency, gain, and bandwidth. In a specific implementation, the substrate can be a rigid or flexible substrate, such as a glass epoxy substrate (with a dielectric constant Dk of 3.8 to 4.5, typically Dk of 4.2), a Teflon substrate (with a dielectric constant Dk of 2.6), a ceramic substrate (with a dielectric constant Dk of 10.0), an epoxy resin substrate (including CEM1 and CEM3 substrates), or a phenolic cotton paper laminate substrate (including FR1, FR2, and FR3 substrates). The insulating material has a much greater impact on the mid-high frequency antenna 300 than on the low frequency antenna 301. The higher the frequency, the lower the loss tangent of the insulating material should be, as this minimizes the impact on the performance of the mid-high frequency antenna 300.

[0179] The high dielectric constant substrate can shrink the antenna because the size of the microstrip monopole antenna follows the following calculation formula:

[0180]

[0181] Where l is the length of the antenna radiating patch, c is the speed of light in free space, and ε r is the relative dielectric constant of the selected dielectric substrate. As can be seen from the above formula, the speed of light is a constant. When the operating frequency f is constant, the antenna length l is inversely proportional to the dielectric constant of the dielectric substrate. That is, the higher the dielectric constant of the dielectric, the shorter the antenna design length. Therefore, using a dielectric substrate with a high dielectric constant can effectively reduce the size of the antenna. However, using a dielectric substrate with a high dielectric constant also has some disadvantages: ε r The larger the value, the stronger the material's ability to restrict electromagnetic waves, the fewer electromagnetic waves propagate out, and the lower the radiation efficiency of the antenna; r The larger the value, the narrower the antenna's radiation frequency band; dielectric substrates with high dielectric constants are more expensive.

[0182] In order to prove the design rationality and practicality of the onboard multi-band monopole microstrip antenna 35 in this embodiment, Figure 1 、 Figure 2 For example, the onboard multi-band monopole microstrip antenna 35 is an LTE antenna. The graphic design of the onboard multi-band monopole microstrip antenna 35 is on the PCB board and is used in vehicle-mounted equipment. It not only saves the cost of additional LTE antennas (such as FPC antenna type), but also has better performance than the FPC antenna type.

[0183] The following details the testing and analysis process for the onboard multi-band monopole microstrip antenna 35. In this embodiment, the test environment for the onboard multi-band monopole microstrip antenna 35 includes an OTA anechoic chamber and a network analyzer. The polarization of the onboard multi-band monopole microstrip antenna 35 is horizontal. Figure 10 Schematic diagram of return loss test of the onboard multi-band monopole microstrip antenna 35. Figure 10 It can be concluded that when the resonant frequency of the low-frequency antenna 301 is 824 MHz, S11 is -3.99700 ( Figure 10 When the resonant frequency of the low-frequency antenna 301 is 960 MHz, S11 is -2.62040 ( Figure 10 The location of point B in FIG); When the resonant frequency of the intermediate frequency antenna 300 is 1.7100 GHz, S11 is -17.0899 ( Figure 10 ); when the resonant frequency of the intermediate frequency antenna 300 is 1.9900 GHz, S11 is -4.30701 ( Figure 10 The position of point D in FIG); When the resonant frequency of the intermediate frequency antenna 300 is 2.0200 GHz, S11 is -4.15010 ( Figure 10 The location of point E in FIG); when the resonant frequency of the intermediate frequency antenna 300 is 2.3000 GHz, S11 is -6.38240 ( Figure 10The location of point F in FIG); When the resonant frequency of the intermediate frequency antenna 300 is 2.4000 GHz, S11 is -6.00352 ( Figure 10 The location of point G in FIG); When the resonant frequency of the intermediate frequency antenna 300 is 2.5700 GHz, S11 is -8.92054 ( Figure 10 The location of point H in FIG); When the resonant frequency of the intermediate frequency antenna 300 is 2.6200 GHz, S11 is -9.93103 ( Figure 10 That is, within the specified operating bandwidth of the mid-high frequency antenna 300 and the low frequency antenna 301, the S11 (return loss) of the mid-high frequency antenna 300 and the low frequency antenna 301, the onboard multi-band monopole microstrip antenna 35 (including the mid-high frequency antenna 300 and the low frequency antenna 301) fully meets the bandwidth design requirements of the LTE antenna in multiple frequency bands.

[0184] Table 1 shows the efficiency of the onboard multi-band monopole microstrip antenna 35 in the frequency bands of 800MHz to 2.7GHz. When the onboard multi-band monopole microstrip antenna 35 operates in the frequency bands of 800MHz to 890MHz, the gain is from 2.17dBi to 3.62dBi, and the efficiency is from 40.05% to 55.94%; when the onboard multi-band monopole microstrip antenna 35 operates in the frequency bands of 900MHz to 960MHz, the gain is from 3.69dBi to 2.67dBi, and the efficiency is from 57.58% to 48.93%; when the onboard multi-band monopole microstrip antenna 35 operates in the frequency bands of 1700MHz to 1780MHz, the gain is from 2.38dBi to 3.64dBi, and the efficiency is from 61.55% to 53.54%; when the onboard multi-band monopole microstrip antenna 35 operates in the frequency bands of When the onboard multi-band monopole microstrip antenna 35 operates at 1800MHz~1880MHz, the gain is from 3.73dBi to 3.11dBi, and the efficiency is from 53.87% to 59%; when the onboard multi-band monopole microstrip antenna 35 operates at 1900MHz~1980MHz, the gain is from 2.82dBi to 1.6dBi, and the efficiency is from 60.09% to 57.22%; when the onboard multi-band monopole microstrip antenna 35 operates at 2000MHz~2080MHz, the gain is from 1.39dBi to 0.56dBi, and the efficiency is from 55.78% to 52.01%; when the onboard multi-band monopole microstrip antenna 35 operates at 2100MHz~ At 2180MHz, the gain is from 0.54dBi to 0.86dBi, and the efficiency is from 51.24% to 44.26%; when the onboard multi-band monopole microstrip antenna 35 operates at 2200MHz to 2280MHz, the gain is from 0.76dBi to 0.26dBi, and the efficiency is from 41.28% to 35.97%; when the onboard multi-band monopole microstrip antenna 35 operates at 2300MHz to 2380MHz, the gain is from 0.12dBi to 0.37dBi, and the efficiency is from 36.1% to 37.74%; when the onboard multi-band monopole microstrip antenna 35 operates at 2400MHz to 2480MHz, the gain is from The gain of the onboard multi-band monopole microstrip antenna 35 is from 0.43dBi to 0.91dBi, and the efficiency is from 37.88% to 46.22%; when the onboard multi-band monopole microstrip antenna 35 operates at 2500MHz to 2580MHz, the gain is from 1.26dBi to 2.62dBi, and the efficiency is from 49.98% to 61.67%; when the onboard multi-band monopole microstrip antenna 35 operates at 2600MHz to 2680MHz, the gain is from 2.79dBi to 2.84dBi, and the efficiency is from 62.48% to 67.96%; when the onboard multi-band monopole microstrip antenna 35 operates at 2700MHz, the gain is 1.66dBi, and the efficiency is 52.67%.Table 1 shows that the efficiency of the onboard multi-band monopole microstrip antenna 35 is lowest at 800 MHz (only 40.05%). However, as the operating frequency increases, the efficiency of the low-frequency antenna 301 in the onboard multi-band monopole microstrip antenna 35 gradually increases. This means that the length of the low-frequency radiator 87 in the low-frequency antenna 301 affects the resonance parameters of the various operating frequency bands near 800 MHz, thereby affecting the efficiency of the low-frequency antenna 301 in the onboard multi-band monopole microstrip antenna 35 in the various operating frequency bands near 800 MHz. At 870 MHz, the efficiency of the low-frequency antenna 301 in the onboard multi-band monopole microstrip antenna 35 has increased to 51.53%. Table 1 shows that the onboard multi-band monopole microstrip antenna 35 (including the mid-high frequency antenna 300 and the low frequency antenna 301) meets the design requirements of LTE antennas in terms of gain and efficiency when tested in various frequency bands between 800 MHz and 2700 MHz, achieving excellent performance within the limited space of the PCB board.

[0185] Table 1

[0186]

[0187]

[0188]

[0189] In the above example, the middle radiator and the end radiator correspond to the first section of the radiator in the above-mentioned first radiator, that is, the first section of the radiator includes the middle radiator and the end radiator; the third section of the radiator, the fourth section of the radiator, the fifth section of the radiator and the sixth section of the radiator correspond to the second section of the radiator in the above-mentioned second radiator, that is, the second section of the radiator includes the third section of the radiator, the fourth section of the radiator, the fifth section of the radiator and the sixth section of the radiator.

[0190] While specific embodiments of the present disclosure have been described above, those skilled in the art will appreciate that these are merely illustrative and that the scope of protection of the present disclosure is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present disclosure, and such changes and modifications are intended to fall within the scope of protection of the present disclosure.

Claims

1. A board-mounted antenna, characterized in that: The onboard antenna is arranged on a substrate, and includes a feeder, a first radiator and a parasitic ground unit. The feeder, the first radiator and the parasitic ground unit are all arranged in a clearance area of the substrate to form a first antenna.

2. The onboard antenna according to claim 1, wherein: The onboard antenna further includes a second radiator. The feed line, the second radiator, and the ground plane of the substrate form a second antenna. The parasitic ground unit is connected to the ground plane. The frequency band of the first antenna is higher than that of the second antenna.

3. The onboard antenna according to claim 2, wherein: The first radiator and the second radiator share a portion of the radiator, and the portion not shared by the first radiator and the second radiator is separated by a slot.

4. The onboard antenna according to claim 1, wherein: The length of the first radiator is consistent with the length of the parasitic ground unit.

5. The onboard antenna according to claim 1, wherein: At least one first slot is formed between the first radiator and the parasitic ground unit, wherein a width of the first slot is related to an electrical performance of the first antenna, and the electrical performance of the first antenna is improved as the width of the first slot increases; The volume of the clearance area is related to the electrical performance of the first antenna, and the electrical performance of the first antenna is improved as the volume of the clearance area increases.

6. The onboard antenna according to any one of claims 1 to 5, characterized in that: The parasitic ground unit includes at least two parasites, the length directions of some parasites are perpendicular to the length direction of the substrate, and the length directions of some parasites are parallel to the length direction of the substrate.

7. The onboard antenna according to claim 2 or 3, characterized in that: The length direction of some of the second radiators is perpendicular to the length direction of the substrate, and the length direction of some of the second radiators is parallel to the length direction of the substrate; In a portion of the second radiator perpendicular to the length direction of the substrate, the minimum distance from the ground plane is positively correlated with the impedance of the second antenna; The length direction of a portion of the second radiator is parallel to the length direction of a portion of the first radiator.

8. The onboard antenna according to claim 2 or 3, characterized in that: The length of the second radiator is consistent with the length of the ground plane; and / or, at least one second slot is formed between the second radiator and the parasitic ground unit, the width of the second slot is related to the electrical performance of the second antenna, and the electrical performance of the second antenna is improved as the width of the second slot increases; And / or, the volume of the clearance area is related to the electrical performance of the second antenna, and the electrical performance of the second antenna improves as the volume of the clearance area increases; And / or, the onboard antenna further includes an antenna matching component, and the second radiator is electrically connected to the ground plane via an inductor in the antenna matching component.

9. The onboard antenna according to claim 3, wherein: The first radiator includes a target segment radiator and a first segment radiator, the second radiator includes the target segment radiator and a second segment radiator, the target segment radiator is connected to the first segment radiator, and the target segment radiator is connected to the second segment radiator through an inductor.

10. The onboard antenna according to claim 8, wherein: The ground pin of the antenna matching component is connected to a first ground pad provided on the substrate; The ground plane includes a first ground copper foil, the first ground copper foil and the antenna matching component are located on the same layer of the substrate, and the first ground copper foil is connected to the first ground pad; The ground plane further includes a second ground copper foil. The second ground copper foil and the first ground copper foil are located on different layers of the substrate. The second ground copper foil is connected to the first ground pad through a first ground via.

11. An electronic device, characterized in that: The invention comprises the on-board antenna according to any one of claims 1 to 10.

12. The electronic device according to claim 11, wherein: The electronic device includes a radio frequency component provided on the substrate, wherein a ground pin of the radio frequency component is connected to a second ground pad provided on the substrate; The ground plane of the substrate includes a third ground copper foil, the third ground copper foil and the RF component are located on the same layer of the substrate, and the third ground copper foil is connected to the second ground pad; The ground plane further includes a fourth ground copper foil. The fourth ground copper foil and the third ground copper foil are located on different layers of the substrate. The fourth ground copper foil is connected to the second ground pad through a second ground via.

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