Antenna protection circuit and electronic equipment
By placing the protection unit between the feeding end of the antenna and the ground, ensuring that its breakdown voltage is higher than the maximum working voltage at the feeding end, the harmonic exceeding the limit caused by leakage current of the metal-enclosed mobile phone antenna at high voltage is solved. Effective discharge of electrostatic energy and signal protection are achieved.
Patent Information
- Application Number
- CN202420317149.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-02-20
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-02-20
AI Technical Summary
The antenna of the metal-enclosed mobile phone is susceptible to electrostatic interference, and the existing protection unit will generate leakage current at high voltage, resulting in harmonic exceeding the limit problem in the GSM900 transmit state.
Place the protection unit, such as a bidirectional transient voltage suppression diode, between the feeding terminal of the antenna and the ground, and its breakdown voltage is greater than the maximum working voltage of the feeding terminal to avoid the generation of leakage current and effectively discharge the electrostatic energy. Arrive to the ground.
Effectively prevent static electricity from damaging the back-end device, avoid harmonic exceeding the limit problem in the transmission state of GSM900, and maintain the stability of signal transmission.
Smart Images
Figure CN222147869U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of electronic equipment, and more specifically, to an antenna protection circuit and electronic equipment. Background Art
[0002] At present, electronic devices with metal casings, such as mobile phones, are becoming more and more popular among consumers. For mobile phones with metal casings, the metal frame is usually used as the antenna, which inevitably leads to the antenna being directly interfered by static electricity. While meeting the requirements of performance and cost, the anti-static ability of the antenna has become a common challenge currently faced by research and development.
[0003] In the related art, the protection unit is usually placed at the main feed end of the antenna. When static electricity hits the antenna, the protection unit can discharge the static electricity energy to the ground to protect the back-end devices from damage. However, the voltage applied to both ends of the silicon-based protection unit used in mobile phones on the market currently has leakage current below 20V. When leakage current is generated, the protection unit is turned on, causing the harmonic limit problem. Specifically, when GSM900 is at the maximum transmission power of 33dBm, since the maximum operating voltage of the main feed end of the antenna is 20V, when the protection unit is placed at the main feed end, the regular sinusoidal wave voltage will cause the protection unit to be regularly turned on and off, so that the useful signal is partially conducted to the ground, causing attenuation, thereby causing the harmonic limit problem in the GSM900 transmission state. Utility Model Content
[0004] One purpose of the utility model is to provide an antenna protection circuit and an electronic device.
[0005] According to one aspect of the utility model, a protection circuit for an antenna is provided, and the protection circuit for the antenna comprises:
[0006] The antenna body is provided with a ground feed terminal;
[0007] A protection unit, wherein a first end of the protection unit is connected to the ground feeding end, and a second end of the protection unit is grounded;
[0008] The protection unit is configured to discharge the energy of electrostatic discharge to the ground, and the breakdown voltage of the protection unit is greater than the maximum operating voltage of the ground feeding terminal.
[0009] In one embodiment, the protection unit is a bidirectional transient voltage suppression diode, the part of the bidirectional transient voltage suppression diode connected to the ground feed end is the first end of the protection unit, and the part of the bidirectional transient voltage suppression diode connected to the ground is the second end of the protection unit.
[0010] In one embodiment, the material of the bidirectional transient voltage suppressor diode is a silicon-based material.
[0011] In one embodiment, the junction capacitance of the bidirectional TVS diode is less than 1 pF.
[0012] In one embodiment, the breakdown voltage of the bidirectional transient voltage suppressor diode is greater than 4.39V.
[0013] In one embodiment, the antenna body is disposed on a metal frame of the electronic device.
[0014] In one embodiment, a matching unit is further provided on the antenna body, and the matching unit is respectively connected to the ground feeding end and the protection unit.
[0015] According to a second aspect of the present invention, an electronic device is provided, comprising a matching circuit for the antenna according to the first aspect of the present invention.
[0016] Through the protection circuit of the antenna of the embodiment of the present invention, the protection unit is set between the ground feed end of the antenna and the ground, and the breakdown voltage of the protection unit is usually greater than the maximum working voltage of the ground feed end. In this way, when static electricity hits the antenna, the protection unit can not only discharge the static electricity discharge energy to the ground to protect the back-end components from damage, but also, because the maximum working voltage of the ground feed end does not exceed the breakdown voltage of the protection unit, the protection unit will not generate leakage current, and thus will not cause the GSM900 harmonic over-limit problem.
[0017] Other features and advantages of the present invention will become apparent from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The accompanying drawings, which constitute a part of the specification, illustrate embodiments of the present utility model and, together with the description, are used to explain the principles of the present utility model.
[0019] Figure 1 This is one of the principle block diagrams of the antenna protection circuit according to the embodiment of the utility model;
[0020] Figure 2 This is the second principle block diagram of the antenna protection circuit according to the embodiment of the utility model;
[0021] Figure 3 This is the third principle block diagram of the antenna protection circuit according to the embodiment of the utility model;
[0022] Figure 4 is a schematic diagram of the principle of the antenna body according to an embodiment of the utility model;
[0023] Figure 5 It is a principle block diagram of an electronic device according to an embodiment of the utility model. DETAILED DESCRIPTION
[0024] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangements of components and steps, numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention.
[0025] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the present invention, its application, or uses.
[0026] Techniques and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the techniques and equipment should be considered part of the specification.
[0027] In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limiting. Therefore, other examples of the exemplary embodiments may have different values.
[0028] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.
[0029] The present disclosure provides an antenna protection circuit, which can be applied to electronic equipment products. The electronic equipment can be a mobile phone, a tablet computer, a wearable device, etc., and its low-frequency antenna has a SAR sensor function. This embodiment is not limited here.
[0030] Combine the following Figure 1 and Figure 2 The structure of the antenna protection circuit 10 according to the embodiment of the present utility model is described.
[0031] like Figure 1 As shown, the antenna protection circuit 10 according to some embodiments of the present invention includes an antenna body 11 and a protection unit 12. The antenna body 11 is provided with a ground feed terminal 111, a first end of the protection unit 12 is connected to the ground feed terminal 111, and a second end of the protection unit 12 is grounded.
[0032] The protection unit 12 is configured to discharge the energy of electrostatic discharge to the ground to protect the back-end devices.
[0033] The breakdown voltage of the protection unit 12 is greater than the maximum operating voltage of the ground feeding terminal 111 .
[0034] The antenna body 11 is arranged on a metal frame of the electronic device.
[0035] The above ground feed end 111 can be referred to as a SAR sensor feed end. A SAR sensor can be understood as a proximity sensor, which is used in electronic devices to detect the proximity between the electronic device and the human body. Figure 4 , a main feed terminal 113 is also provided on the antenna body 11, and the ground feed terminal 111 and the main feed terminal 113 are usually located at different positions of the antenna body 11, and due to the standing wave characteristics of the antenna, the voltages at different positions are usually different, that is, the maximum operating voltages of the ground feed terminal 111 and the main feed terminal 113 are usually different. According to the experimental simulation data, the maximum operating voltage of the main feed terminal 113 is usually 20V, which occurs when GSM900 is at the maximum transmission power of 33dBm, and the maximum operating voltage of the ground feed terminal 111 is 4.39V, which occurs when LTE B71 is transmitting. This shows that, on the one hand, the protection unit 12 with a breakdown voltage greater than 4.39V is placed between the ground feed terminal 111 and the ground terminal. At this time, the maximum operating voltage of the ground feed terminal 111 is less than the breakdown voltage of the protection unit 12, and the protection unit 12 will not generate leakage current, and will not cause the GSM900 harmonic over-limit problem. On the other hand, when static electricity hits the antenna, the energy of the static electricity discharge is discharged to the ground through the protection unit 12, which effectively protects the back-end devices. In this way, the static electricity discharge problem of the low-frequency antenna is solved, and the GSM900 harmonic over-limit problem caused by the nonlinear characteristics of the protection unit 12 is also solved.
[0036] Through the embodiments of the present disclosure, the protection unit is arranged between the ground feed end of the antenna and the ground, and the breakdown voltage of the protection unit is usually greater than the maximum working voltage of the ground feed end. In this way, when static electricity hits the antenna, the protection unit can not only discharge the static electricity discharge energy to the ground to protect the back-end devices from damage, but also, because the maximum working voltage of the ground feed end does not exceed the breakdown voltage of the protection unit, the protection unit will not generate leakage current, and thus will not cause the GSM900 harmonic over-limit problem.
[0037] In one embodiment, referring to Figure 2 and Figure 3 A matching unit 112 is also provided on the antenna body 11, and the matching unit 112 is connected to the ground feeding terminal 111 and the protection unit 12 respectively.
[0038] Reference Figure 3 The protection unit 12 may be a transient voltage suppressor diode (TVS), specifically a bidirectional transient voltage suppressor diode, that is, the transient voltage suppressor diode is bidirectional. The part where the bidirectional transient voltage suppressor diode is connected to the ground feed terminal 111 is the first end of the protection unit 12, and the part where the bidirectional transient voltage suppressor diode is connected to the ground is the second end of the protection unit 12.
[0039] Typically, a bidirectional transient voltage suppression diode has a low clamping characteristic. When static electricity hits the antenna, the low clamping characteristic of the bidirectional transient voltage suppression diode can instantly clamp the high voltage of the static electricity discharge to a low voltage, so that the back-end device is borne by the low voltage clamped by the bidirectional transient voltage suppression diode, thereby avoiding damage to the matching unit 12.
[0040] Among them, the material of the bidirectional transient voltage suppression diode is silicon-based material. Due to the good reliability of silicon-based material, the transient voltage suppression diode will not fail even after multiple static electricity, and can continue to protect the back-end devices from damage.
[0041] Among them, the junction capacitance of the bidirectional transient voltage suppression diode is less than 1pF, so the loss to the antenna is low.
[0042] Among them, the breakdown voltage of the bidirectional transient voltage suppression diode is greater than 4.39 V. This is because the maximum operating voltage of the ground feed terminal 111 in this embodiment is 4.39 V. If the bidirectional transient voltage suppression diode with a breakdown voltage greater than 4.39 V is placed at the ground feed terminal 111, the maximum operating voltage of the ground feed terminal 111 will not exceed the breakdown voltage of the bidirectional transient voltage suppression diode, and the useful signal will not be conducted to the ground through the bidirectional transient voltage suppression diode, and thus the harmonic over-limit problem in the GSM900 transmission state will not occur.
[0043] Specifically, a silicon-based bidirectional transient voltage suppression diode is added to the ground feed end 111 of the low-frequency antenna. For example, the breakdown voltage of the silicon-based bidirectional transient voltage suppression diode is higher than 6V, and the junction capacitance is 0.2pF. When GSM900 is at the maximum transmission power of 33dBm, due to the different voltages at different positions of the GSM900 low-frequency antenna, the maximum operating voltage of the ground feed end 111 in this embodiment is 4.39V. The voltage of the silicon-based bidirectional transient voltage suppression diode cannot reach its own breakdown voltage, and there will be no harmonic over-limit problem. When static electricity hits the low-frequency antenna, after the voltage of the silicon-based bidirectional transient voltage suppression diode reaches the breakdown voltage, the silicon-based bidirectional transient voltage suppression diode has a ground conduction impedance of less than 1Ω, and the static electricity energy will be immediately discharged to the ground through this low-impedance path and clamped to a lower voltage value, so that the components on the low-frequency antenna circuit can be effectively protected from being damaged by static electricity, and the silicon-based bidirectional transient voltage suppression diode has high reliability and stable performance.
[0044] In the related art, an inductor L1 to ground is usually added to the main feed end, and a capacitor C1 is connected in series. The inductor L1 is usually 10nH~56nH, and the capacitor C1 is usually 33pF~100pF, so as to discharge the electrostatic energy to the ground. However, it will cause large insertion loss and poor electrostatic clamping characteristics, greatly attenuate useful signals, and cannot effectively protect the electrostatically sensitive devices at the back end, which may easily cause device damage.
[0045] In the related technology, silicon-based bidirectional transient voltage suppression diodes are usually placed at the main feed end. The low clamping characteristics of silicon-based bidirectional transient voltage suppression diodes can instantly clamp the high voltage of electrostatic discharge to a low voltage, so that the voltage borne by the back-end device is the voltage clamped by the silicon-based bidirectional transient voltage suppression diode. In addition, in order to reduce the loss of the antenna, that is, to have less impact on the antenna, the junction capacitance of the silicon-based bidirectional transient voltage suppression diode is usually required to be smaller. However, the silicon-based bidirectional transient voltage suppression diode manufacturers can currently achieve that when the voltage across the two ends of the silicon-based bidirectional transient voltage suppression diode that meets the low junction capacitance is lower than 20V, leakage current will be generated. When leakage current is generated, it will cause GSM900 harmonic problems. Specifically, when GSM900 is at the maximum transmission power of 33dBm, the maximum operating voltage of the main feed end is usually 20V. At this time, if a silicon-based bidirectional transient voltage suppression diode with a low clamping voltage is placed at the main feed end, the regular sinusoidal wave voltage will cause the silicon-based bidirectional transient voltage suppression diode to be regularly turned on and off, causing the useful signal to be partially conducted to the ground, causing attenuation and causing the harmonic exceeding the limit problem in the GSM900 transmission state.
[0046] That is to say, the solution of placing silicon-based bidirectional transient voltage suppression diodes at the main feed end, although the electrostatic clamping voltage is low and can effectively protect the back-end devices from electrostatic damage, will cause GSM900 harmonic over-limit problems due to the nonlinear characteristics of silicon-based bidirectional transient voltage suppression diodes. At present, there is no silicon-based bidirectional transient voltage suppression diode with a breakdown voltage below 20V that does not generate mA-level leakage current, and the current transient voltage suppression diode manufacturers have not yet produced silicon-based bidirectional transient voltage suppression diodes with low junction capacitance, breakdown voltage higher than 20V, and no mA-level leakage current for the main feed end.
[0047] In the related art, the junction capacitance of ceramic transient voltage suppression diodes is usually 0.05pF, and the insertion loss is usually 0.004dB@2.4GHz, which has very little attenuation on useful signals. In addition, the breakdown voltage of ceramic transient voltage suppression diodes is usually 100V~400V. When GSM900 is in the maximum power transmission state, the ceramic transient voltage suppression diode will not break down, the antenna performance will not decline, and there will be no harmonic over-limit problems. However, the reliability of ceramic transient voltage suppression diodes is poor. After experiencing static electricity many times, the ceramic transient voltage suppression diodes will lose the function of protecting the back-end devices, causing damage to the back-end devices.
[0048] The present disclosure also provides an electronic device, referring to Figure 5, the electronic device 20 includes any one of the antenna protection circuits 10 provided in the above circuit embodiment section. In this embodiment, the electronic device can be a mobile phone, a tablet computer, a wearable device, etc., and its low-frequency antenna has a sar sensor function. In this embodiment, since the electronic device provided by the embodiment of the present disclosure includes any one of the antenna protection circuits provided in the above antenna protection circuit embodiment section, the electronic device provided by the embodiment of the present disclosure can achieve the same function as any one of the antenna protection circuits provided in the above antenna protection circuit embodiment section. That is, the protection unit is set between the ground feed end and the ground of the antenna, and the breakdown voltage of the protection unit is greater than the maximum working voltage of the ground feed end, so that when static electricity hits the antenna, the protection unit can not only discharge the static electricity energy to the ground to protect the back-end device from damage, but also, since the maximum working voltage of the ground feed end does not exceed the breakdown voltage of the protection unit, the protection unit will not generate leakage current, and thus will not cause the GSM900 harmonic over-limit problem.
[0049] The above embodiments mainly focus on describing the differences from other embodiments, but it should be clear to those skilled in the art that the above embodiments can be used alone or in combination with each other as needed.
[0050] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are for illustration only and are not intended to limit the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.
Claims
1. A protection circuit for an antenna, characterized in that: include: An antenna body, wherein a ground feed terminal is provided on the antenna body; A protection unit, wherein a first end of the protection unit is connected to the ground feeding end, and a second end of the protection unit is grounded; The protection unit is configured to discharge the energy of electrostatic discharge to the ground, and the breakdown voltage of the protection unit is greater than the maximum operating voltage of the ground feeding terminal.
2. The antenna protection circuit according to claim 1, characterized in that: The protection unit is a bidirectional transient voltage suppression diode, the part of the bidirectional transient voltage suppression diode connected to the ground feeding end is the first end of the protection unit, and the part of the bidirectional transient voltage suppression diode connected to the ground is the second end of the protection unit.
3. The antenna protection circuit according to claim 2, characterized in that: The bidirectional transient voltage suppression diode is made of silicon-based material.
4. The antenna protection circuit according to claim 2, characterized in that: The junction capacitance of the bidirectional transient voltage suppression diode is less than 1 pF.
5. The antenna protection circuit according to claim 2, characterized in that: The breakdown voltage of the bidirectional transient voltage suppression diode is greater than 4.39V.
6. The antenna protection circuit according to claim 3, characterized in that: The antenna body is arranged on a metal frame of the electronic device.
7. The antenna protection circuit according to claim 1, characterized in that: The antenna body is also provided with a matching unit, and the matching unit is respectively connected to the ground feeding end and the protection unit.
8. An electronic device, characterized in that: include: The protection circuit for the antenna according to any one of claims 1 to 7.