Low-frequency antenna and electronic communication equipment

Abstract

The utility model discloses a low-frequency antenna and an electronic communication device. The low-frequency antenna comprises a low-frequency antenna body and an antenna tuning circuit. A radio frequency signal contact point and a grounding contact point are arranged on the low-frequency antenna body; the antenna tuning circuit is used for tuning the working frequency band of the low-frequency antenna body, the signal input end of the antenna tuning circuit is connected with the radio frequency signal contact point of the low-frequency antenna body, and the signal output end of the antenna tuning circuit is used for being electrically connected with the low-frequency-band radio frequency processing circuit. According to the low-frequency antenna provided by the utility model, the working frequency band of the low-frequency antenna body can be tuned by arranging the antenna tuning circuit, the performance of the low-frequency antenna can be optimized through tuning, and compared with the conventional low-frequency antenna with small clearance, the passive efficiency of the low-frequency antenna can be improved by 1dB-2dB, so that higher antenna design requirements can be met.

Description

TECHNICAL FIELD

[0001] The utility model relates to an antenna, especially to a low-frequency antenna and electronic communication equipment. BACKGROUND

[0002] With the gradual perfection of 5G network and the improvement of people's living standards, the demand for electronic communication equipment is also growing. As the main application platform of 5G technology in electronic communication equipment, smart phones are constantly evolving in design and function to meet user needs. With the gradual popularization of 5G mobile phones, the frequency band required by the antenna is more and more, and the number of antennas involved is also more, and people's aesthetic standards are becoming more and more strict. For antenna engineers, the antenna challenge for small clearance projects (1.5mm and below) is getting higher and higher, and modern spectrum is getting less and less, and the frequency of the ultra-low frequency band is severely depleted, and the problem of frequency band reuse is also very important. Therefore, it is necessary to improve the design scheme of the low-frequency antenna so as to be applicable to the project which is difficult to debug and has an ultra-low frequency band.

[0003] In addition, the screen ratio is one of the important indicators to measure customer experience. In the case of unchanged whole machine size, reducing the frame of the mobile phone screen will increase the length-width ratio, thereby increasing the screen ratio and allowing users to have a larger screen use experience. Compared with ordinary mobile phones, full-screen mobile phones have narrower top and tail areas and narrower frames, however, the full-screen design also brings many challenges to the whole machine. For example, the front camera, fingerprint recognition, earpiece, distance sensor and antenna and other components need to be adjusted and designed adaptively. In particular, the antenna, as a key component of mobile phone signal transmission and reception, is more affected in the full-screen design. Although the physical structure of the antenna is simple, its design and structure are very complex, and many aspects of the internal environment of the mobile phone need to be considered. The clearance of the antenna in the full-screen mobile phone is reduced, while the performance indicators of the antenna are relatively high. This makes it difficult for conventional antenna debugging processes such as LDS, FPC, etc. to meet the needs, bringing challenges to the optimization and debugging of the antenna. UTILITY MODEL CONTENT

[0004] One of the purposes of the utility model is to provide a low-frequency antenna which can improve the performance of the low-frequency antenna to meet higher antenna design requirements.

[0005] In order to achieve the above purpose, the utility model provides a low-frequency antenna, which comprises:

[0006] The low-frequency antenna body is provided with a radio frequency signal contact point and a grounding contact point; and

[0007] The antenna tuning circuit is used to tune the working frequency band of the low-frequency antenna body. The signal input end of the antenna tuning circuit is connected to the radio frequency signal contact point of the low-frequency antenna body, and the signal output end is used to be electrically connected to the low-frequency band radio frequency processing circuit.

[0008] Furthermore, the antenna tuning circuit is configured on an antenna board, and a spring is provided on the antenna board at a signal input end corresponding to the antenna tuning circuit; the radio frequency signal contact point of the low-frequency antenna body elastically abuts against the spring.

[0009] Furthermore, the antenna tuning circuit includes:

[0010] a first matching branch, a first end of which is electrically connected to the signal input terminal, and a second end of which is electrically connected to the low-frequency band radio frequency processing circuit; and

[0011] The second matching branch has a first end electrically connected to the signal input end and a second end grounded; the first matching branch and the second matching branch are used to cooperate with each other to achieve tuning of the working frequency band of the low-frequency antenna body.

[0012] Furthermore, the first matching branch includes:

[0013] a first connecting device, a first end of which is electrically connected to the signal input end;

[0014] a tuning capacitor component, a first end of which is electrically connected to the second end of the first connecting device;

[0015] A first switch regulating unit, which is connected in parallel with the tuning capacitor component;

[0016] a second switch regulating unit, a first end of which is electrically connected to the first end of the tuning capacitor component, a second end of which is electrically connected to the second end of the tuning capacitor component, and a third end of which is grounded;

[0017] a second connecting device, a first end of which is electrically connected to the second end of the tuning capacitor component, and a second end of which is used to be electrically connected to the low-frequency band radio frequency processing circuit; and

[0018] a first protection device, a first end of which is electrically connected to the first end of the first connection device, and a second end of which is grounded;

[0019] The second matching branch includes:

[0020] a third connecting device, a first end of which is electrically connected to the signal input end;

[0021] a third switch regulating unit, a first end of which is electrically connected to the second end of the third connecting device, and a second end of which is grounded;

[0022] a tuning inductor component, a first end of which is electrically connected to the first end of the third connecting device, and a second end of which is grounded; and

[0023] The second protection device has a first end electrically connected to the first end of the third connection device and a second end grounded.

[0024] Furthermore, the first connecting device, the second connecting device and the third connecting device are all 0 ohm resistors; and / or

[0025] The first protection device and the second protection device are both transient voltage suppressors; and / or

[0026] The tuning capacitor component includes a fixed capacitor and an adjustable capacitor connected in parallel.

[0027] Furthermore, the first switch regulating unit includes a first control switch and a first resonant device connected in series with the first control switch;

[0028] The second switch regulating unit includes:

[0029] a second control switch, a first end of which is electrically connected to the second end of the tuning capacitor component;

[0030] a second resonant device, a first end of which is electrically connected to the first end of the second control switch, and a second end of which is grounded;

[0031] a third control switch, a first end of which is electrically connected to the first end of the tuning capacitor component;

[0032] a third resonant device, a first end of which is electrically connected to the first end of the third control switch, and a second end of which is grounded;

[0033] a fourth control switch, a first end of which is electrically connected to the first end of the tuning capacitor component; and

[0034] a fourth resonant device, a first end of which is electrically connected to the first end of the fourth control switch, and a second end of which is grounded;

[0035] The third switch regulating unit includes:

[0036] a first regulating branch, a first end of which is electrically connected to the second end of the third connecting device and a second end of which is grounded; the first regulating branch comprises a fifth control switch and a fifth resonant device connected in series;

[0037] a second regulating branch connected in parallel with the first regulating branch; the second regulating branch comprising a sixth control switch and a sixth resonant device connected in series;

[0038] a third regulating branch connected in parallel with the first regulating branch; the third regulating branch comprising a seventh control switch and a seventh resonant device connected in series; and

[0039] A fourth regulating branch is connected in parallel with the first regulating branch; the fourth regulating branch comprises an eighth control switch and an eighth resonant device connected in series.

[0040] Further, the first resonant device, the second resonant device, the third resonant device, the fourth resonant device, the fifth resonant device, the seventh resonant device and the eighth resonant device are inductors, and the sixth resonant device is a 0-ohm resistor.

[0041] Further, the low-frequency antenna body is made by using a film injection molding process and an LDS laser engraving process, or the low-frequency antenna body is made by using an FPC material.

[0042] Another one of the purposes of the utility model is to provide an electronic communication device which can still meet the communication requirement of a low-frequency band when the size of a clearance area is small.

[0043] In order to achieve the above-mentioned purposes, the utility model provides a low-frequency antenna which comprises a shell and a low-frequency antenna installed in the shell.

[0044] Further, the low-frequency antenna body adopts an "L" shaped structure, comprises a horizontal section, a vertical section and an arc section connecting the horizontal section and the vertical section, the radio frequency signal contact point is arranged on the horizontal section, and the grounding contact point is arranged on the vertical section; a main board is arranged at a position close to one short side edge in the shell, an antenna plate of the low-frequency antenna is arranged at a position close to the other opposite short side edge in the shell, and the antenna plate is provided with a spring piece at a signal input end corresponding to an antenna tuning circuit;

[0045] The vertical section of the low-frequency antenna body is distributed along the one long side edge, and the horizontal section is distributed along the other opposite short side edge; the grounding contact point at the vertical section is electrically connected to the ground of the main board, and the signal contact point on the horizontal section is located above the antenna plate and elastically abuts against the spring piece of the antenna plate.

[0046] The low-frequency antenna has the following beneficial effects: the antenna tuning circuit can tune the working frequency band of the low-frequency antenna body, and the performance of the low-frequency antenna can be optimized; the passive efficiency of the low-frequency antenna efficiency can reach about -7dB to -8dB; compared with the performance of the low-frequency antenna with a small clearance in the prior art, the passive efficiency can be improved by 1dB to 2dB, so that higher antenna design requirements can be met. BRIEF DESCRIPTION OF DRAWINGS

[0047] Figure 1 is a structural schematic view of a low-frequency antenna body in an embodiment of the low-frequency antenna of the utility model.

[0048] Figure 2It is a circuit diagram of an antenna tuning circuit in one embodiment of the low-frequency antenna of the present invention.

[0049] Figure 3 This is a performance index curve diagram obtained by testing multiple frequency bands in one embodiment of the low-frequency antenna of the present invention.

[0050] Figure 4 It is a structural diagram of an embodiment of the electronic communication device of the present utility model. DETAILED DESCRIPTION

[0051] The low-frequency antenna and electronic communication device described in the present invention will be further explained below in conjunction with the accompanying drawings and specific implementation methods. However, this explanation does not constitute an improper limitation on the technical solution of the present invention.

[0052] See Figure 1 and Figure 2 , Figure 1 It is a structural schematic diagram of a low-frequency antenna body in one embodiment of the low-frequency antenna of the present utility model. Figure 2 This is a circuit diagram of the antenna tuning circuit of an embodiment of the low-frequency antenna of the present invention. Figure 1 and Figure 2 The low frequency antenna is described as an example to more clearly illustrate the various components and coordination relationships of the low frequency antenna. Figure 1 and Figure 2 The specific embodiment shown is described in detail as an example, but this specific embodiment is not used to limit the scope of the low-frequency antenna of the present invention. Except for the components that solve the necessary technical problems of the present invention (the low-frequency antenna body 100 and the antenna tuning circuit below), the remaining components can be regarded as non-essential technical elements. These non-essential technical elements can be replaced by other technical elements with the same or similar functions or structures in other embodiments, or these non-essential technical elements may not be needed in other embodiments.

[0053] Figure 1 and Figure 2 In the illustrated embodiment, the low-frequency antenna includes a low-frequency antenna body 100 and an antenna tuning circuit. The low-frequency antenna body 100 is provided with a radio frequency signal contact point 101 and a ground contact point 102, through which the low-frequency antenna body 100 is electrically connected to an external circuit.

[0054] The low-frequency antenna body 100 can be made by combining the in-mold injection molding process and the LDS (Laser Direct Structuring) laser engraving process. When making the low-frequency antenna body 100, a sheet-like antenna matrix is ​​first obtained by in-mold injection molding of a laser-activated plastic of a metal structure composite, and then the area in the antenna matrix that needs to be metallized is laser activated to form a seed layer, and finally a metal conductive layer is formed on the seed layer by chemical plating, thereby making the low-frequency antenna body 100. The LDS laser engraving process can be used to give ordinary plastic components / circuit boards electrical interconnection functions, component support functions, and plastic shell support and protection functions, as well as shielding, antenna and other functions generated by the combination of mechanical entities and conductive patterns. The low-frequency antenna body 100 is made by combining in-mold injection molding with the LDS laser engraving process, which can make the consistency and durability of the low-frequency antenna body 100 more stable. Of course, in order to further reduce the thickness of the low-frequency antenna body 100 , the low-frequency antenna body 100 may also be made of FPC material. FPC is a highly reliable and excellent flexible printed circuit board made of polyimide or polyester film as a base material.

[0055] Please continue to see Figure 1 , Figure 1 In the embodiment shown, since the electrical length required for the low-frequency antenna is relatively long, the low-frequency antenna body 100 may adopt an "L"-shaped structure, which includes a horizontal section 110, a vertical section 120, and an arc section 130 connecting the horizontal section 110 and the vertical section 120. When the low-frequency antenna body 100 is assembled in the housing 300 of the electronic communication device (such as Figure 4 When the electronic communication device is mounted on a vertical section 120, the vertical section 120 may be disposed along a long side edge, and the horizontal section 110 may be disposed along a short side edge of the electronic communication device. The RF signal contact point 101 described above may be configured to be disposed on the horizontal section 110, and the ground contact point 102 may be configured to be disposed on the vertical section 120.

[0056] Please continue to see Figure 2 The antenna tuning circuit is used to tune the operating frequency band of the low-frequency antenna body 100. The signal input terminal RF IN of the antenna tuning circuit is connected to the radio frequency signal contact point 101 of the low-frequency antenna body 100, and the signal output terminal RF OUT of the antenna tuning circuit is used to be electrically connected to the low-frequency band radio frequency processing circuit PA.

[0057] The antenna tuning circuit may include a first matching branch 201 and a second matching branch 202. The first end of the first matching branch 201 is electrically connected to the signal input terminal RF IN, and the second end of the first matching branch 201 serves as the signal output terminal RF OUT of the antenna tuning circuit and is electrically connected to the low-band RF processing circuit PA. The first end of the second matching branch 202 is electrically connected to the signal input terminal RF IN, and the second end of the second matching branch 202 is grounded. The first matching branch 201 and the second matching branch 202 cooperate to achieve tuning of the operating frequency band of the low-frequency antenna body 100.

[0058] The antenna tuning circuit may further include a fourth connecting device, which may be configured as a 0-ohm resistor R4. When the switching adjustment unit (i.e., the first switching adjustment unit, the second switching adjustment unit, and the third switching adjustment unit) is required to tune the operating frequency band of the low-frequency antenna body 100, both ends of the 0-ohm resistor R4 are disconnected; when the switching adjustment unit is not required for tuning, the first end of the 0-ohm resistor R4 is electrically connected to the signal input terminal RF IN, and the second end thereof is grounded.

[0059] The first matching branch 201 may include a first connector, a tuning capacitor assembly, a first switch adjustment unit, a second switch adjustment unit, a second connector, and a first protection device. A first end of the first connector is electrically connected to the signal input terminal RF IN, and a second end of the first connector is electrically connected to the first end of the tuning capacitor assembly. Preferably, the first connector may be configured as a 0-ohm resistor R1. The tuning capacitor assembly may include a fixed capacitor C1 and an adjustable capacitor C2 connected in parallel. By adjusting the adjustable capacitor C2, the capacitive reactance of the antenna tuning circuit is fine-tuned, thereby optimizing the performance of the low-frequency antenna.

[0060] The first switch regulation unit is connected in parallel with the tuning capacitor component. The first switch regulation unit may include a first control switch SW1 and a first resonant device RF1 connected in series with the first control switch SW1. When the first control switch SW1 is open, the first resonant device RF1 is disconnected from the circuit. When the first control switch SW1 is closed, the first resonant device RF1 is connected to the circuit in parallel with the tuning capacitor component. Preferably, the first resonant device RF1 can be configured as a 10nH inductor.

[0061] A first end of the second switch regulating unit is electrically connected to a first end of the tuning capacitor component, a second end of the second switch regulating unit is electrically connected to a second end of the tuning capacitor component, and a third end of the second switch regulating unit is grounded. The second switch regulating unit may include a second control switch SW2, a second resonant device RF2, a third control switch SW3, a third resonant device RF3, a fourth control switch SW4, and a fourth resonant device RF4.

[0062] The first end of the second control switch SW2 is electrically connected to the second end of the fixed capacitor C1, the first end of the second resonant device RF2 is electrically connected to the first end of the second control switch SW2, and the second end of the second resonant device RF2 is grounded. The first end of the third control switch SW3 is electrically connected to the first end of the fixed capacitor C1, the first end of the third resonant device RF3 is electrically connected to the first end of the third control switch SW3, and the second end of the third resonant device RF3 is grounded. The first end of the fourth control switch SW4 is electrically connected to the first end of the fixed capacitor C1, the first end of the fourth resonant device RF4 is electrically connected to the first end of the fourth control switch SW4, and the second end of the fourth resonant device RF4 is grounded. Whether the second resonant device RF2 is connected to the circuit can be controlled by turning the second control switch SW2 on and off, whether the third resonant device RF3 is connected to the circuit can be controlled by turning the third control switch SW3 on and off, and whether the fourth resonant device RF4 is connected to the circuit can be controlled by turning the fourth control switch SW4 on and off. Preferably, the second resonant device RF2 may be configured as an inductor of 7.5 nH, the third resonant device RF3 may be configured as an inductor of 56 nH, and the fourth resonant device RF4 may be configured as an inductor of 33 nH.

[0063] The second switch adjustment unit may further include a ninth control switch SW2', a tenth control switch SW3', and an eleventh control switch SW4'. The ninth control switch SW2' is turned on and off oppositely to the second control switch SW2, the tenth control switch SW3' is turned on and off oppositely to the third control switch SW3, and the eleventh control switch SW4' is turned on and off oppositely to the fourth control switch SW4. As a result, when the second control switch SW2 is turned off, the two ends of the second resonant device RF2 are short-circuited. When the third control switch SW3 is turned off, the two ends of the third resonant device RF3 are short-circuited. When the fourth control switch SW4 is turned off, the two ends of the fourth resonant device RF4 are short-circuited. This prevents interference to the circuit caused by electromagnetic induction in the second resonant device RF2, the third resonant device RF3, and the fourth resonant device RF4 when the second control switch SW2, the third control switch SW3, and the fourth control switch SW4 are turned off.

[0064] The first end of the second connector is electrically connected to the second end of the fixed capacitor C1, and the second end of the second connector is electrically connected to the low-band RF processing circuit PA. The second connector can be configured as a 0-ohm resistor R2.

[0065] The first end of the first protection device is electrically connected to the first end of the first connection device, and the second end of the first protection device is grounded. The first protection device is used to protect the first matching branch 201 from damage to components of the first matching branch 201 due to excessive voltage. The first protection device can be a transient voltage suppressor TVS1.

[0066] The second matching branch 202 includes a third connecting component, a third switching regulating unit, a tuning inductor component, and a second protection component. A first end of the third connecting component is electrically connected to the signal input terminal RF IN, a second end is electrically connected to the first end of the third switching regulating unit, and a second end of the third switching regulating unit is grounded. The third connecting component can be configured as a 0-ohm resistor R3.

[0067] The third switch regulation unit includes a first regulation branch, a second regulation branch, a third regulation branch, and a fourth regulation branch connected in parallel. The first regulation branch includes a fifth control switch SW5 and a fifth resonant device RF5 connected in series, the second regulation branch includes a sixth control switch SW6 and a sixth resonant device RF6 connected in series, the third regulation branch includes a seventh control switch SW7 and a seventh resonant device RF7 connected in series, and the fourth regulation branch includes an eighth control switch SW8 and an eighth resonant device RF8 connected in series. Whether the fifth resonant device RF5 is connected to the circuit can be controlled by turning the fifth control switch SW5 on and off, whether the sixth resonant device RF6 is connected to the circuit can be controlled by turning the sixth control switch SW6 on and off, whether the seventh resonant device RF7 is connected to the circuit can be controlled by turning the seventh control switch SW7 on and off, and whether the eighth resonant device RF8 is connected to the circuit can be controlled by turning the eighth control switch SW8 on and off. Preferably, the fifth resonant device RF5 can be configured as a 12nH inductor, the sixth resonant device RF6 can be configured as a 0 ohm resistor, the seventh resonant device RF7 can be configured as a 47nH inductor, and the eighth resonant device RF8 can be configured as a 4.7nH inductor.

[0068] The fifth control switch SW5 has the same on / off function as the first control switch SW1 and can serve as the first group of control switches. Both control switches can be controlled by the same control signal. The sixth control switch SW6 has the same on / off function as the second control switch SW2 and can serve as the second group of control switches. Both control switches can be controlled by the same control signal. The seventh control switch SW7 has the same on / off function as the third control switch SW3 and can serve as the third group of control switches. Both control switches can be controlled by the same control signal. The eighth control switch SW8 has the same on / off function as the fourth control switch SW4 and can serve as the fourth group of control switches. Both control switches can be controlled by the same control signal. Therefore, the first resonant device RF1 and the fifth resonant device RF5 are simultaneously connected to the circuit, the second resonant device RF2 and the sixth resonant device RF6 are simultaneously connected to the circuit, the third resonant device RF3 and the seventh resonant device RF7 are simultaneously connected to the circuit, and the fourth resonant device RF4 and the eighth resonant device RF8 are simultaneously connected to the circuit.

[0069] The first switch adjustment unit and the second switch adjustment unit may be antenna tuning switch QAT3550, and the third switch adjustment unit may be antenna tuning switch QAT3518. The on-off switching of the control switch in the antenna tuning switch is generally controlled by a CPU.

[0070] The first end of the tuning inductor component is electrically connected to the first end of the third connecting device, and the second end of the tuning inductor component is grounded. The tuning inductor component can use an inductor L1 of 270nH.

[0071] The first end of the second protection device is electrically connected to the first end of the third connection device, and the second end of the second protection device is grounded. The second protection device is used to protect the second matching branch 202 from damage to components in the second matching branch 202 due to excessive voltage. The second protection device can be a transient voltage suppressor TVS2.

[0072] Based on the above embodiment, the working process of the low-frequency antenna described in the present invention is as follows: when the first control switch SW1, the second control switch SW2, the third control switch SW3, the fourth control switch SW4, the fifth control switch SW5, the sixth control switch SW6, the seventh control switch SW7 and the eighth control switch SW8 are all disconnected (at this time, the ninth control switch SW2', the tenth control switch SW3' and the eleventh control switch SW4' are all closed), the first resonant device RF1, the second resonant device RF2, the third resonant device RF3, the fourth resonant device RF4, the fifth resonant device RF5, the sixth resonant device RF6, the seventh resonant device RF7 and the eighth resonant device RF8 are not connected to the circuit, and the operating frequency band of the low-frequency antenna body 100 is 610MHz~700MHz, which can be used for communication in the B71 frequency band.

[0073] When the first control switch SW1 and the fifth control switch SW5 are turned on, and the second control switch SW2, the third control switch SW3, the fourth control switch SW4, the sixth control switch SW6, the seventh control switch SW7 and the eighth control switch SW8 are turned off (at this time, the ninth control switch SW2', the tenth control switch SW3' and the eleventh control switch SW4' are all closed), the first resonant device RF1 and the fifth resonant device RF5 are connected to the circuit, and the second resonant device RF2, the third resonant device RF3, the fourth resonant device RF4, the sixth resonant device RF6, the seventh resonant device RF7 and the eighth resonant device RF8 are not connected to the circuit. The operating frequency band of the low-frequency antenna body 100 is 740MHz to 800MHz, which can be used for communication in the B13 / B14 frequency band.

[0074] When the first control switch SW1, the second control switch SW2, the third control switch SW3, the fourth control switch SW4, the fifth control switch SW5, the sixth control switch SW6, the seventh control switch SW7 and the eighth control switch SW8 are all closed (at this time, the ninth control switch SW2', the tenth control switch SW3' and the eleventh control switch SW4' are all disconnected), the first resonant device RF1, the second resonant device RF2, the third resonant device RF3, the fourth resonant device RF4, the fifth resonant device RF5, the sixth resonant device RF6, the seventh resonant device RF7 and the eighth resonant device RF8 are all connected to the circuit, and the operating frequency band of the low-frequency antenna body 100 is 880 MHz to 960 MHz, which can be used for communication in the B8 frequency band.

[0075] Since there are four groups of control switches in this embodiment, in addition to the three combinations of all four groups of control switches being on, all four groups of control switches being off, and the first group of control switches being on while the other three groups of control switches are off, there are also more control combinations. Through different control combinations, the low-frequency antenna body 100 can also be used for communication in other frequency bands such as the B5 / B20 / B26 band and the B12 / B17 band. Figure 3 When the low-frequency antenna operates in the B71 band, B8 band, B13 / B14 band, B5 / B20 / B26 band or B12 / B17 band, after optimizing the low-frequency antenna by selecting the corresponding resonant device through the antenna tuning circuit, the passive efficiency of the low-frequency antenna can generally reach about -7dB to -8dB.

[0076] In summary, the low-frequency antenna of the present invention has the following beneficial effects: by setting the antenna tuning circuit, the working frequency band of the low-frequency antenna body 100 can be tuned, and the performance of the low-frequency antenna can be optimized. The general passive efficiency of the low-frequency antenna efficiency can reach about -7dB to -8dB; compared with the performance of the previous low-frequency antenna with small clearance (generally around -9dB), its passive efficiency can be improved by 1dB to 2dB, so that it can meet the design requirements of projects with higher requirements such as operator standards, and is suitable for projects with relatively small clearance (1.5mm and below), complex environment, greater debugging difficulty, and ultra-low frequency bands.

[0077] See Figure 4 , Figure 4 This is a schematic diagram of the structure of an embodiment of the electronic communication device of the present invention. The electronic communication device includes but is not limited to a handheld phone (such as a 5G mobile phone), a tablet with communication function, etc. Figure 4 In the illustrated embodiment, the electronic communication device includes a housing 300 and a low-frequency antenna mounted within the housing 300. A main board 310 is disposed within the housing 300 near one short side edge, and an antenna plate 210 of the low-frequency antenna is disposed near the other, opposite short side edge. The antenna tuning circuit may be configured on the antenna plate 210 of the electronic communication device. A spring (not shown) for connecting to the antenna body 100 is provided on the antenna plate 210 at the signal input terminal RF IN of the antenna tuning circuit, thereby facilitating electrical connection between the low-frequency antenna body 100 and the antenna plate 210.

[0078] The low-frequency antenna body 100 is disposed within the housing 300 in an area near one of the long side edges, wherein the vertical section 120 of the low-frequency antenna body 100 is distributed along one of the long side edges, and the horizontal section 110 is distributed along the other, opposite short side edge. The ground contact point 102 on the vertical section 120 is electrically connected to the ground of the mainboard 310. The ground contact point 102 can be electrically connected to the ground of the mainboard 310 via a transfer, or directly to the ground of the mainboard 310. The signal contact point 101 on the horizontal section 110 is located above the antenna sub-plate 210 and elastically abuts against the spring clip of the antenna sub-plate 210.

[0079] The electronic communication device of the present invention has the following beneficial effects: the clearance area size of its low-frequency antenna body 100 can be much smaller than 2.5 mm. When the clearance area size reaches 1.5 mm or less, it can still meet the communication requirements of the low-frequency band. It is more suitable for electronic communication devices such as full-screen mobile phones with small antenna clearance and high antenna performance indicators.

[0080] It should be noted that the existing technology in the scope of protection of the present utility model is not limited to the embodiments given in the present application documents. All existing technologies that do not contradict the solutions of the present utility model, including but not limited to prior patent documents, prior public publications, prior public uses, etc., can be included in the scope of protection of the present utility model.

[0081] In addition, the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0082] It should also be noted that the above-listed embodiments are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above-listed embodiments, and similar variations or modifications that can be directly derived from or easily conceived by those skilled in the art based on the disclosure of the present invention are intended to fall within the scope of protection of the present invention.

Claims

1. A low-frequency antenna, characterized in that: include: A low-frequency antenna body, which is provided with a radio frequency signal contact point and a ground contact point; as well as The antenna tuning circuit is used to tune the working frequency band of the low-frequency antenna body. The signal input end of the antenna tuning circuit is connected to the radio frequency signal contact point of the low-frequency antenna body, and the signal output end is used to be electrically connected to the low-frequency band radio frequency processing circuit.

2. The low-frequency antenna according to claim 1, wherein: The antenna tuning circuit is configured on an antenna board, and a spring is provided on the antenna board at a signal input end corresponding to the antenna tuning circuit; the radio frequency signal contact point of the low-frequency antenna body elastically abuts against the spring.

3. The low-frequency antenna according to claim 1, wherein: The antenna tuning circuit comprises: a first matching branch, a first end of which is electrically connected to the signal input terminal, and a second end of which is electrically connected to the low-frequency band radio frequency processing circuit; and The second matching branch has a first end electrically connected to the signal input end and a second end grounded; the first matching branch and the second matching branch are used to cooperate with each other to achieve tuning of the working frequency band of the low-frequency antenna body.

4. The low-frequency antenna according to claim 3, wherein: The first matching branch includes: a first connecting device, a first end of which is electrically connected to the signal input end; a tuning capacitor component, a first end of which is electrically connected to the second end of the first connecting device; A first switch regulating unit, which is connected in parallel with the tuning capacitor component; a second switch regulating unit, a first end of which is electrically connected to the first end of the tuning capacitor component, a second end of which is electrically connected to the second end of the tuning capacitor component, and a third end of which is grounded; a second connecting device, a first end of which is electrically connected to the second end of the tuning capacitor component, and a second end of which is used to be electrically connected to the low-frequency band radio frequency processing circuit; and a first protection device, a first end of which is electrically connected to the first end of the first connection device, and a second end of which is grounded; The second matching branch includes: a third connecting device, a first end of which is electrically connected to the signal input end; a third switch regulating unit, a first end of which is electrically connected to the second end of the third connecting device, and a second end of which is grounded; a tuning inductor component, a first end of which is electrically connected to the first end of the third connecting device, and a second end of which is grounded; and The second protection device has a first end electrically connected to the first end of the third connection device and a second end grounded.

5. The low-frequency antenna according to claim 4, characterized in that: The first connecting device, the second connecting device and the third connecting device are all 0 ohm resistors; and / or The first protection device and the second protection device are both transient voltage suppressors; and / or The tuning capacitor component includes a fixed capacitor and an adjustable capacitor connected in parallel.

6. The low-frequency antenna according to claim 4, characterized in that: The first switch regulating unit includes a first control switch and a first resonant device connected in series with the first control switch; The second switch regulating unit includes: a second control switch, a first end of which is electrically connected to the second end of the tuning capacitor component; a second resonant device, a first end of which is electrically connected to the first end of the second control switch, and a second end of which is grounded; a third control switch, a first end of which is electrically connected to the first end of the tuning capacitor component; a third resonant device, a first end of which is electrically connected to the first end of the third control switch, and a second end of which is grounded; a fourth control switch, a first end of which is electrically connected to the first end of the tuning capacitor component; and a fourth resonant device, a first end of which is electrically connected to the first end of the fourth control switch, and a second end of which is grounded; The third switch regulating unit includes: a first regulating branch, a first end of which is electrically connected to the second end of the third connecting device and a second end of which is grounded; the first regulating branch comprises a fifth control switch and a fifth resonant device connected in series; a second regulating branch connected in parallel with the first regulating branch; the second regulating branch comprising a sixth control switch and a sixth resonant device connected in series; a third regulating branch connected in parallel with the first regulating branch; the third regulating branch comprising a seventh control switch and a seventh resonant device connected in series; and A fourth regulating branch is connected in parallel with the first regulating branch; the fourth regulating branch includes an eighth control switch and an eighth resonant device connected in series.

7. The low-frequency antenna according to claim 6, characterized in that: The first resonant device, the second resonant device, the third resonant device, the fourth resonant device, the fifth resonant device, the seventh resonant device, and the eighth resonant device are all inductors, and the sixth resonant device is a 0-ohm resistor.

8. The low-frequency antenna according to claim 6, wherein: The low-frequency antenna body is made of an in-mold injection molding process and an LDS laser engraving process, or the low-frequency antenna body is made of an FPC material.

9. An electronic communication device, characterized in that: The invention comprises a housing and the low-frequency antenna according to any one of claims 1 to 8 installed in the housing.

10. The electronic communication device according to claim 9, wherein: The low-frequency antenna body adopts an "L"-shaped structure, including a horizontal section, a vertical section, and an arc-shaped section connecting the horizontal and vertical sections. The RF signal contact point is provided on the horizontal section, and the ground contact point is provided on the vertical section. A main board is provided near one of the short side edges within the housing, and a small antenna board of the low-frequency antenna is provided near the other opposite short side edge within the housing. A spring is provided on the small antenna board corresponding to the signal input terminal of the antenna tuning circuit. The vertical section of the low-frequency antenna body is distributed along one of the long side edges, and the horizontal section is distributed along the other opposite short side edge; the grounding contact point at the vertical section is electrically connected to the ground of the main board, and the signal contact point on the horizontal section is located above the antenna board and elastically abuts against the spring clip of the antenna board.

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