Antenna circuit and electronic equipment

Abstract

The invention discloses an antenna circuit and electronic equipment, and the antenna circuit comprises a first antenna which is fixedly disposed on a housing of the electronic equipment; the contact piece is electrically connected with the first antenna; the antenna elastic piece is arranged on the circuit board, and the antenna elastic piece is in contact with the contact piece; one end of the first power supply is electrically connected with the contact piece, and the other end of the first power supply is electrically connected with the antenna elastic piece; the ceramic capacitor is arranged on the circuit board; the first input end of the operational amplifier is used for inputting a reference signal, and the second input end of the operational amplifier is electrically connected with the contact piece; the output end of the operational amplifier is electrically connected with the control end of the first switching device, the first end of the first switching device is used for accessing a power supply signal, and the second end of the first switching device is electrically connected with the ceramic capacitor; the antenna circuit is switched between a first working state and a second working state based on the contact resistance between the antenna elastic sheet and the contact sheet; in the first working state, the antenna elastic sheet vibrates along with the vibration of the ceramic capacitor.

Description

Technical Field

[0001] This application belongs to the field of electronics, specifically relating to an antenna circuit and an electronic device. Background Technology

[0002] During reliability testing of mobile devices (such as salt spray, hand sweat, and drop tests) and long-term user use, antenna contacts may experience increased impedance due to liquid corrosion or mechanical wear. This impedance change can cause antenna frequency shift or a decrease in feed current, leading to a decline in antenna performance. Severe performance degradation can directly cause location services to fail, ultimately rendering all applications reliant on location services unusable. Therefore, improving antenna impedance is a pressing issue that needs to be addressed. Summary of the Invention

[0003] The purpose of this application is to provide an antenna circuit and electronic device that can solve the problem of antenna performance degradation caused by increased antenna impedance.

[0004] In a first aspect, embodiments of this application provide an antenna circuit, including:

[0005] The first antenna is fixed to the housing of the electronic device;

[0006] A contact piece, which is electrically connected to the first antenna;

[0007] An antenna spring is disposed on a circuit board, and the antenna spring contacts the contact piece;

[0008] A first power source, one end of which is electrically connected to the contact piece, and the other end of which is electrically connected to the antenna spring piece;

[0009] Ceramic capacitors are mounted on the circuit board;

[0010] An operational amplifier, wherein a first input terminal of the operational amplifier is used to input a reference signal, and a second input terminal of the operational amplifier is electrically connected to the contact piece;

[0011] The first switching device has its output terminal of the operational amplifier electrically connected to the control terminal of the first switching device, its first terminal being used to receive a power signal, and its second terminal being electrically connected to the ceramic capacitor.

[0012] Based on the contact resistance between the antenna spring and the contact piece, the antenna circuit switches between a first operating state and a second operating state: when the antenna circuit is in the first operating state, the output of the operational amplifier controls the first switching device to turn on, and the antenna spring vibrates with the vibration of the ceramic capacitor; when the antenna circuit is in the second operating state, the output of the operational amplifier controls the first switching device to turn off, and the antenna spring stops vibrating.

[0013] Secondly, embodiments of this application also provide an electronic device, including the antenna circuit described above.

[0014] In this embodiment, when the contact resistance between the antenna spring and the contact piece is large, the voltage input to the operational amplifier increases, and the output signal of the operational amplifier controls the first switching device to turn on. The antenna circuit is in the first working state, the ceramic capacitor vibrates, and the antenna spring vibrates with the vibration of the ceramic capacitor. During the vibration process, the antenna spring can remove the oxide layer or debris, thereby reducing the contact resistance between the antenna spring and the contact piece. Attached Figure Description

[0015] Figure 1 This is a circuit diagram of an antenna circuit provided in an embodiment of this application;

[0016] Figure 2 This is a front view of an antenna circuit provided in an embodiment of this application;

[0017] Figure 3 This is a left view of an antenna circuit provided in an embodiment of this application;

[0018] Figure 4 This is a structural diagram of an antenna spring provided in an embodiment of this application, wherein (a) is a cross-sectional view of the front view, (b) is a top view, (c) is a cross-sectional view of the left view before assembly, and (d) is a cross-sectional view of the left view after assembly.

[0019] Figure 5 This is a left view of another antenna circuit provided in an embodiment of this application;

[0020] Figure 6 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application;

[0021] Figure 7 This is a schematic diagram of the working timing of an antenna spring cleaning mode provided in an embodiment of this application;

[0022] Figure 8 This is a flowchart illustrating an antenna spring cleaning method provided in an embodiment of this application. Detailed Implementation

[0023] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0024] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0025] The antenna circuits and methods provided in this application will be described in detail below with reference to the accompanying drawings, through specific embodiments and application scenarios.

[0026] See Figure 1 , Figure 1 This is an antenna circuit provided in an embodiment of this application. For example... Figure 1 As shown, the antenna circuit includes:

[0027] The first antenna 11 is fixed to the housing of the electronic device;

[0028] Contact piece 12, which is electrically connected to the first antenna 11;

[0029] Antenna spring 13 is disposed on circuit board 14, and antenna spring 13 is in contact with contact piece 12;

[0030] A first power supply 15, one end of which is electrically connected to the contact piece 12, and the other end of which is electrically connected to the antenna spring piece 13.

[0031] A ceramic capacitor 16 is disposed on the circuit board 14;

[0032] Operational amplifier 17, the first input terminal of which is used to input a reference signal, and the second input terminal of which is electrically connected to the contact piece 12;

[0033] The first switching device 18, the output terminal of the operational amplifier 17 is electrically connected to the control terminal of the first switching device 18, the first terminal of the first switching device 18 is used to receive a power signal, and the second terminal of the first switching device 18 is electrically connected to the ceramic capacitor 16.

[0034] Based on the contact resistance between the antenna spring 13 and the contact piece 12, the antenna circuit switches between a first operating state and a second operating state: when the antenna circuit is in the first operating state, the output of the operational amplifier 17 controls the first switching device 18 to turn on, and the antenna spring 13 vibrates with the vibration of the ceramic capacitor 16; when the antenna circuit is in the second operating state, the output of the operational amplifier 17 controls the first switching device 18 to turn off, and the antenna spring 13 stops vibrating.

[0035] The first antenna 11 can be a mid-frame antenna or a flexible printed circuit board (FPC) antenna.

[0036] Contact piece 12 can be a main upper gasket or a main upper spring.

[0037] Antenna spring 13 of electronic devices, such as antenna spring corresponding to a Global Positioning System (GPS) antenna, or other antenna springs.

[0038] The first power supply 15 is electrically connected to the contact piece 12 and the antenna spring 13 respectively, and is used to supply power to the contact resistance between the contact piece 12 and the antenna spring 13. In addition, a voltage divider resistor can be set, which is connected in series with the contact resistance across the first power supply 15; or a transistor or the like can be set in series with the contact resistance, so that the voltage division of the contact resistance can be detected by an operational amplifier.

[0039] The ceramic capacitor 16 can be a multilayer ceramic capacitor (MLCC). A single ceramic capacitor patch can be configured according to the actual situation, such as only configuring a capacitor patch that vibrates tangentially or normally; alternatively, two capacitor patches can be configured simultaneously, allowing the ceramic capacitor to vibrate in different directions.

[0040] The antenna spring 13 and the ceramic capacitor 16 can be respectively disposed on the same side of the circuit board 14 or on opposite sides. In order to improve the vibration effect, the antenna spring 13 and the ceramic capacitor 16 can be located in the same area or close to each other on the circuit board 14.

[0041] The first switching device 18 may be an NMOS switch, with its first terminal connected to a power supply DC-DC converter, which may be used to power an amplifier RF power amplifier (PA). The second terminal of the NMOS switch is electrically connected to a ceramic capacitor 16.

[0042] During long-term use, the antenna spring 13 of electronic devices is prone to forming an oxide layer due to liquid corrosion and debris accumulation due to mechanical wear. These conditions can all lead to an increase in the contact resistance between the antenna spring 13 and the contact piece 12.

[0043] In the first operating state of the antenna circuit, the contact resistance between the antenna spring 13 and the contact piece 12 is relatively large, resulting in an increased voltage amplitude input to the operational amplifier 17 through the second input terminal. The operational amplifier 17 compares the voltage division corresponding to the contact resistance with the reference voltage Vref corresponding to the reference signal input at the first input terminal. The reference voltage Vref can be preset or manually adjusted according to actual conditions.

[0044] When the voltage divider exceeds the reference voltage Vref, the operational amplifier 17 outputs a signal, driving the first switching device 18 to turn on. The power supply for the RF PA then inputs a periodic voltage waveform with a large voltage difference to the first switching device 18. The dielectric layer of the ceramic capacitor 16 exhibits a piezoelectric effect when voltage is applied, causing the capacitor to expand and contract. This high-frequency vibration of the ceramic capacitor 16 generates high-frequency micro-vibrations between the antenna spring 13 and the contact piece 12, effectively removing oxides, dirt, and other impurities.

[0045] The antenna spring can be fixed to the circuit board via a base. When the ceramic capacitor vibrates, it causes the circuit board to vibrate, which in turn causes the antenna spring to vibrate. The antenna spring may also include a free end. When the free end of the antenna spring comes into contact with the ceramic capacitor, the ceramic capacitor can directly transmit the vibration to the antenna spring, thereby improving the vibration effect of the antenna spring.

[0046] In the second operating state of the antenna circuit, the voltage division corresponding to the contact resistance between the antenna spring 13 and the contact piece 12 is small, and the voltage amplitude input to the operational amplifier 17 through the second input terminal is reduced. When the voltage is less than the reference voltage Vref, the output terminal of the operational amplifier 17 outputs a signal, the first switching device 18 is turned off, the antenna spring 13 stops vibrating, and the antenna circuit is in normal operating state.

[0047] Over time, the contact impedance of antennas in electronic devices can increase, leading to problems such as antenna frequency deviation and decreased feed current. This is especially true for GPS antennas, which rely on a single frequency. When the frequency deviation is too large, GPS performance is essentially lost, affecting applications that depend on GPS positioning. The decrease in feed current can also cause positioning functionality to fail.

[0048] Current technical solutions to the above problems include using gold-plated springs, which is costly and cannot prevent long-term corrosion; and using a sealed structure, which requires increasing the thickness of the electronic device. In both methods, when the contact resistance of the contact piece 12 and the antenna spring 13 is high, the user cannot clean the internal contact points independently.

[0049] When the surface resistance reaches a certain level, vibration is generated through the piezoelectric effect of the switching power supply capacitor, removing dirt, oxides, and other foreign matter from the contact spring. This method reduces the fluctuation range of the contact spring's contact impedance, eliminates the need for precious metal plating and waterproofing, thus reducing costs. It utilizes existing RF power networks, requiring no additional board space.

[0050] In this embodiment of the application, when the contact resistance between the antenna spring 13 and the contact piece 12 is large, the operational amplifier 17 outputs a signal to drive the first switching device 18 to conduct, thereby causing the ceramic capacitor 16 to vibrate. The vibration of the ceramic capacitor 16 drives the antenna spring 13 to vibrate. During the vibration process, the antenna spring 13 can remove the oxide layer or debris, thereby reducing the contact resistance between the antenna spring 13 and the contact piece 12, so that the contact resistance returns to normal.

[0051] In addition, the above methods can be used to detect and improve the contact resistance of the antenna feed point and ground.

[0052] The angle between the vibration direction of the first capacitor patch 161 and the vibration direction of the second capacitor patch 162 is between 30° and 150°. Optionally, as... Figure 2 As shown, the vibration directions of the first capacitor patch 161 and the second capacitor patch 162 are perpendicular.

[0053] like Figure 2 As shown, the ceramic capacitor 16 may include two capacitor patches, namely the first capacitor patch 161 and the second capacitor patch 162.

[0054] By adjusting the positions of the first and second capacitor patches, the two capacitor patches can vibrate in different directions, thereby improving the vibration effect.

[0055] To better understand the positional relationship between the two capacitor patches, such as Figure 2In the coordinate system shown, the length direction of the first capacitor patch 161 and the second capacitor patch 162 can be set along the z-axis of the coordinate system; the width direction of the first capacitor patch 161 is along the y-axis, and the height direction is along the x-axis; the width direction of the second capacitor patch 162 is along the x-axis, and the height direction is along the y-axis. When the first capacitor patch 161 vibrates, it vibrates along the y-axis (also known as normal vibration), and when the second capacitor patch 162 vibrates, it vibrates along the x-axis (also known as tangential vibration), thereby realizing that the two capacitor patches vibrate in different directions.

[0056] In practical applications, the specific positions of the two capacitor patches on the circuit board 14 can be set according to vibration requirements. For example, the first capacitor patch 161 can be set to vibrate along the x-axis, and the second capacitor patch 162 can vibrate along the y-axis.

[0057] In some implementations, capacitors that meet the following requirements can be selected:

[0058] Capacitance: 10-100nF (Low Equivalent Series Resistance (ESR) type);

[0059] Size: 0402 / 0201 (high vibration sensitivity). The larger the capacitor size and the larger the capacitance value, the easier it is to generate capacitive vibration.

[0060] During installation, high-viscosity conductive adhesive can be used for fixation to enhance vibration transmission.

[0061] When a voltage is applied, the dielectric layer of ceramic capacitor 16 exhibits a piezoelectric effect, causing the capacitor to expand and contract. Under alternating current (based on engineering experience, a voltage difference greater than 1V across ceramic capacitor 16 will produce significant vibration, while the dynamic range of RF power supplies is typically 0–5V), the positive and negative piezoelectric effects alternate, also causing vibration of circuit board 14. However, the amplitude of the vibration of ceramic capacitor 16 is usually very small (only about 1pm to 1nm), having minimal impact on ceramic capacitor 16 itself and adjacent components, and will not cause reliability issues.

[0062] Capacitor patches 16 and antenna springs 13 are respectively arranged on opposite sides of the circuit board 14. The capacitor patches are located on the back of the antenna springs 13. The two capacitor patches have the same length direction and a 90° difference in the width direction, meaning they are perpendicular in the width direction. When the two capacitors 16 vibrate, they can generate normal vibration and tangential vibration respectively. The normal vibration can impact the propagation of microcracks in the oxide layer to remove corrosion products; the tangential motion removes debris / contaminant particles through micro-friction sliding. Through normal and tangential vibration, the crystal structure of the oxide layer can be destroyed and particulate contaminants can be scraped off, thus improving the cleaning effect.

[0063] Optionally, the ceramic capacitor 16 and the antenna spring 13 are disposed opposite each other on opposite sides of the circuit board 14.

[0064] like Figure 2 and Figure 3 As shown, the antenna spring 13 is fixedly disposed on one side of the circuit board 14; the ceramic capacitor 16 is fixedly disposed on the other side of the circuit board 14, and the antenna spring 13 and the ceramic capacitor 16 are located in the same area of ​​the circuit board 14, so that the ceramic capacitor 16 is located on the back of the antenna spring 13. In this way, when the ceramic capacitor 16 vibrates, it can drive the antenna spring 13 to vibrate, which can improve the vibration effect of the antenna spring 13.

[0065] In the above manner, the vibration of the ceramic capacitor 16 can induce the vibration of the antenna spring 13, thereby achieving the effect of removing debris and reducing impedance. Furthermore, the above method facilitates the layout of the ceramic capacitor 16.

[0066] Optionally, such as Figure 1 and Figure 3 As shown, the antenna spring 13 includes a base 131 and a connecting part 132 connected to the base 131. The antenna spring 13 is fixed to the circuit board 14 through the base 131, and the free end of the connecting part is in contact with the contact piece 12.

[0067] The antenna spring 13 includes a base 131 and a connecting part 132. The antenna spring is fixed to the circuit board 14 by the base. The free end of the connecting part 132 is the free end of the antenna spring 13, also known as the tongue, which can move under the action of external force.

[0068] In some implementations, such as Figure 3 As shown, the connecting portion 132 of the antenna spring 13 extends upward.

[0069] In some implementations, such as Figure 4 and Figure 5 As shown, the antenna spring 13 includes a base 131 and a connecting part 132 connected to the base. The antenna spring 13 is fixed to the circuit board 14 through the base. The ceramic capacitor 16 is located on the same side of the circuit board 14 as the antenna spring 13. The base 131 has a hollow structure. The ceramic capacitor 16 is located in the cavity of the base 131. The base 131 and the ceramic capacitor 16 are electrically insulated from each other.

[0070] like Figure 4 As shown in (c), the connecting portion 132 of the antenna spring 13 in this embodiment includes a bent portion that is C-shaped, which is more than Figure 3 The connecting part 132 shown is longer.

[0071] When the antenna spring 13 is not fully installed, the end of the connecting portion 132 of the antenna spring 13 is bent toward the base 131. When the antenna spring 13 is fully installed, the contact piece 12 contacts the outside of the connecting portion 132, the connecting portion 132 of the antenna spring 13 moves closer to the base 131, and the end of the connecting portion 132 contacts the insulating area of ​​the ceramic capacitor 16.

[0072] The vibration of the ceramic capacitor 16 can be directly transmitted to the contact piece 12 through the connection part 132, thereby improving the vibration effect.

[0073] like Figure 5 As shown, the antenna spring 13 is fixed to the circuit board 14 by the base 131. The base 131 of the antenna spring 13 has a hollow cavity in the middle. The ceramic capacitor 16 is fixed (e.g., soldered) on the circuit board 14 and is located in the cavity of the base 131.

[0074] In some implementations, such as Figure 4 As shown in (b), the ceramic capacitor 16 is disposed in the cavity of the base 131, and there is a gap between the periphery of the ceramic capacitor 16 and the inner sidewall of the cavity of the base 131. That is to say, the periphery of the ceramic capacitor 16 is not in contact with the inner sidewall of the cavity of the base 131, thereby achieving electrical insulation between the ceramic capacitor 16 and the base 131.

[0075] In some embodiments, the ceramic capacitor 16 can be electrically insulated from the base 131 by providing an insulating material between the inner wall of the cavity of the base 131 and the ceramic capacitor 16.

[0076] By placing the ceramic capacitor 16 inside the cavity of the base 131, the vibration energy absorbed by the base 131 can be reduced when the ceramic capacitor 16 vibrates, thereby improving the vibration effect of the antenna spring 13.

[0077] Optionally, the connecting portion 132 includes a bent portion that is in contact with the contact piece 12 and the ceramic capacitor 16.

[0078] To improve the transmission effect of vibration from ceramic capacitor 16 to antenna spring 13, in Figure 3 Based on the antenna spring 13 shown, the connecting part 132 is extended to obtain Figure 4 The antenna spring 13 shown is shown. The connecting part 132 includes a bent part, which is in the shape of an inverted "C" and the end of the bent part extends toward the base 131.

[0079] With the antenna spring 13 installed, the contact piece 12 presses the bent portion of the antenna spring 13 together. The end of the bent portion of the antenna spring 13 extends into the cavity of the base 131 and contacts the insulating part of the ceramic capacitor 16 inside the cavity, i.e., the bent portion abuts against the ceramic capacitor 16. When the ceramic capacitor 16 vibrates, the vibration effect can be directly transmitted to the antenna spring 13 through the ceramic capacitor 16, which can improve the vibration effect of the antenna spring 13 and improve the cleaning effect.

[0080] Optionally, such as Figure 1 As shown, the antenna circuit also includes a voltage divider resistor 19, the first end of which is electrically connected to the contact piece 12, and the second end of which is connected to the first power supply 15.

[0081] The contact resistance formed between the antenna spring 13 and the contact piece 12 is connected in series with the voltage divider resistor 19 across the first power supply 15. The operational amplifier 17 controls the first switching device 18 to turn on or off based on the voltage division of the contact resistance and the reference signal.

[0082] like Figure 1 As shown, the contact resistance and resistance R1 between the antenna spring 13 and the contact piece 12 are in series, and the first power supply 15 is used to supply power to the contact resistance and resistance R1.

[0083] The voltage divider input of the contact resistance is fed to operational amplifier 17, which determines its output by comparing it with a reference voltage Vref. In some embodiments, the range of contact resistance can be obtained when the contact piece 12 and the antenna spring 13 are in good contact, and the reference voltage Vref is dynamically set according to the normal range of contact resistance.

[0084] When the contact resistance of the antenna spring 13 increases, the voltage amplitude input to the operational amplifier 17 increases, and the operational amplifier 17 outputs a signal that drives the NMOS switch to turn on. At this time, the switching power supply DC-DC powering the RF PA outputs a periodic voltage waveform with a large voltage difference. The multilayer ceramic capacitor 16 will generate high-frequency vibrations through the piezoelectric effect, thereby generating high-frequency micro-vibrations between the antenna spring 13 and the contact piece 12.

[0085] When the contact resistance of the antenna spring 13 decreases, the voltage input to the operational amplifier 17 decreases, the operational amplifier 17 stops outputting, the switching transistor turns off, the contact impedance of the mobile phone antenna spring 13 returns to normal, and the ceramic capacitor 16 does not vibrate or stops vibrating.

[0086] By connecting the voltage divider resistor (R1) 19 in series with the contact resistor to form a voltage divider detection circuit, the change in contact resistance between the antenna spring 13 and the contact piece 12 can be quantified. The input resistance of the operational amplifier 17 is very high and will not affect the radio frequency signal.

[0087] By setting a voltage divider resistor 19 to detect the voltage division corresponding to the contact resistance between the contact piece 12 and the antenna spring 13, the accuracy of contact resistance detection can be improved.

[0088] Optionally, such as Figure 1 As shown, the antenna circuit also includes a low-pass filter 20. The negative terminal of the first power supply 15 is electrically connected to the first end of the low-pass filter 20, and the second end of the low-pass filter 20 is electrically connected to the antenna spring 13.

[0089] In some implementations, such as Figure 1 As shown, the low-pass filter consists of an inductor L1 and a capacitor C1. The first end of the inductor is connected to the negative terminal of the first power supply 15, and the second end is connected to the antenna spring 13; the first end of the capacitor is grounded, and the second end is connected to the negative terminal of the power supply.

[0090] In some implementations, the low-pass filter can be a low-pass filter that encapsulates an inductor and a capacitor.

[0091] Low-pass filters have very high impedance relative to radio frequency signals, so they do not affect the transmission of radio frequency signals, reduce interference to antenna signals, and improve signal reception.

[0092] Optionally, when the signal strength of the first antenna is greater than a threshold, the antenna circuit is controlled to be in the second operating state;

[0093] When the signal strength of the first antenna is less than a threshold, the antenna circuit switches from the second operating state to the first operating state.

[0094] When the signal strength of the first antenna (such as a GPS antenna) is greater than a preset threshold, the antenna circuit is in the second working state, that is, the normal working state, and the cleaning mode is not triggered.

[0095] When the signal strength of the first antenna (such as a GPS antenna) is less than a preset threshold, it is determined that the antenna spring 13 has poor contact, and the antenna circuit is controlled to switch to the first working state, that is, to start the cleaning mode.

[0096] Specifically, when the antenna circuit switches to the first operating state, the antenna circuit detects the voltage division corresponding to the contact resistance between the antenna spring 13 and the contact piece 12, and inputs the voltage division to the operational amplifier 17. The operational amplifier 17 determines that the voltage division is greater than the reference voltage value and outputs a control signal to drive the first switching device 18 to conduct, thereby realizing the capacitive vibration described in the above embodiment.

[0097] In some implementations, such as Figure 6 As shown, a microstrip coupler can be added to the GPS path to detect the antenna's signal strength. When the cellular antenna or Wi-Fi antenna transmits a signal, the antenna's transmit power is obtained. WTR stands for Wireless Transceiver. Based on the correlation between GPS theoretical coupling power, transmit power, and antenna isolation, the theoretical coupling power of the GPS antenna can be obtained using the pre-acquired antenna isolation (known at the factory) and the antenna's transmit power. Comparing the actual coupling power with the theoretical coupling power determines whether there are any anomalies in the GPS path, i.e., whether the antenna signal is normal.

[0098] When the antenna signal strength is less than the threshold and the contact resistance is high, a comprehensive judgment is made that the spring is dirty and oxidized, and the cleaning mode is activated, which can improve the confidence of the test results.

[0099] When the antenna signal strength is greater than the threshold, the cleaning mode can be left unactivated, and the antenna circuit can remain in normal working condition, or switch to normal working condition, i.e., the second working condition.

[0100] By using indicators such as microstrip couplers and signal strength, the effectiveness of contact impedance optimization can be evaluated or improved, which can reduce misjudgments caused by a single method and improve the confidence of the detection results.

[0101] Optionally, the antenna circuit further includes a second power supply 21 for supplying power to the operational amplifier 17, the operational amplifier 17 being connected to the second power supply 21 via a second switching device 22;

[0102] When the signal strength of the first antenna 11 is less than a threshold, the second switching device 22 is controlled to close.

[0103] If the signal strength of the first antenna is greater than the threshold, the second switching device 22 is controlled to disconnect.

[0104] When the signal strength of the first antenna is less than the threshold, the second switch is closed, the second power supply 21 supplies power to the operational amplifier, and the antenna circuit is in the first working state, that is, the cleaning mode is started.

[0105] When the signal strength of the first antenna is greater than the threshold, the second switching device is turned off, the second power supply 21 stops supplying power to the operational amplifier, and the antenna circuit is in the second working state, that is, the normal working state.

[0106] In some implementations, the cleaning mode can be automatically triggered and cleaning activated only when operating in TDD bands (such as Band 40, n41, n78). When the cleaning mode needs to be activated, the second switching device 22 can be closed to achieve automatic cleaning.

[0107] The timing sequence of the RF PA in Time Division Duplex (TDD) mode is as follows: Figure 7 As shown, the RF power supply operates in the TDD band with a 200Hz cycle.

[0108] When operational amplifier 17 detects the need to activate the cleaning mode for GPS antenna spring 13, it turns on the first switching device 18 (i.e., the NMOS switch). At this time, a 200Hz voltage difference is generated across the two ceramic capacitors 16. The 200Hz switching current of the RF PA in TDD (Time Division Duplex) mode can excite periodic deformation of the MLCC ceramic dielectric. During TDD operation, dirt on the GPS antenna is cleaned until the contact impedance of the GPS antenna is detected to be normal, at which point the first switching device 18 turns off. The above process can be found in [reference needed]. Figure 8 As shown.

[0109] By combining the antenna signal strength and the contact resistance of the antenna spring 13, a comprehensive judgment is made on whether the antenna needs to start the cleaning mode, thereby improving the confidence of the detection results and reducing misjudgments.

[0110] This application embodiment also provides a method such as Figure 6 The electronic device shown includes the antenna circuit as described above.

[0111] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element. Furthermore, it should be noted that the scope of the methods and apparatuses in the embodiments of this application is not limited to performing functions in the order shown or discussed, but may also include performing functions substantially simultaneously or in the reverse order, depending on the functions involved. For example, the described methods may be performed in a different order than described, and various steps may be added, omitted, or combined. Additionally, features described with reference to certain examples may be combined in other examples.

[0112] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a computer software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes several instructions to cause a terminal (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods described in the various embodiments of this application.

[0113] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. An antenna circuit, characterized in that, include: The first antenna is fixed to the housing of the electronic device; A contact piece, which is electrically connected to the first antenna; An antenna spring is disposed on a circuit board, and the antenna spring contacts the contact piece; A first power source, one end of which is electrically connected to the contact piece, and the other end of which is electrically connected to the antenna spring piece; Ceramic capacitors are mounted on the circuit board; An operational amplifier, wherein a first input terminal of the operational amplifier is used to input a reference signal, and a second input terminal of the operational amplifier is electrically connected to the contact piece; The first switching device has its output terminal of the operational amplifier electrically connected to the control terminal of the first switching device, its first terminal being used to receive a power signal, and its second terminal being electrically connected to the ceramic capacitor. Based on the contact resistance between the antenna spring and the contact piece, the antenna circuit switches between a first operating state and a second operating state: When the antenna circuit is in the first working state, the output of the operational amplifier controls the first switching device to turn on, and the antenna spring vibrates with the vibration of the ceramic capacitor; When the antenna circuit is in the second operating state, the output of the operational amplifier controls the first switching device to open, and the antenna spring stops vibrating.

2. The antenna circuit according to claim 1, characterized in that, The ceramic capacitor includes a first capacitor patch and a second capacitor patch; The angle between the vibration direction of the first capacitor patch and the vibration direction of the second capacitor patch is between 30° and 150°.

3. The antenna circuit according to claim 1, characterized in that, The ceramic capacitor and the antenna spring are disposed on opposite sides of the circuit board.

4. The antenna circuit according to claim 1, characterized in that, The antenna spring includes a base and a connecting part connected to the base. The antenna spring is fixed to the circuit board by the base, and the free end of the connecting part is in contact with the contact piece.

5. The antenna circuit according to claim 1, characterized in that, The antenna spring includes a base and a connecting part connected to the base. The antenna spring is fixed to the circuit board by the base. The ceramic capacitor is located on the same side of the circuit board as the antenna spring. The base has a hollow structure. The ceramic capacitor is disposed in the cavity of the base. The base is electrically insulated from the ceramic capacitor. The connecting portion includes a bent portion, which is in contact with the contact piece and also in contact with the ceramic capacitor.

6. The antenna circuit according to claim 1, characterized in that, The antenna circuit further includes a voltage divider resistor, the first end of which is electrically connected to the contact piece, and the second end of which is connected to the first power supply. The contact resistance formed between the antenna spring and the contact piece is connected in series with the voltage divider resistor across the first power supply. The operational amplifier controls the first switching device to turn on or off based on the voltage division of the contact resistance and the reference signal.

7. The antenna circuit according to claim 1, characterized in that, The antenna circuit further includes a low-pass filter, the negative terminal of the first power supply is electrically connected to the first end of the low-pass filter, and the second end of the low-pass filter is electrically connected to the antenna spring.

8. The antenna circuit according to any one of claims 1 to 7, characterized in that, When the signal strength of the first antenna is greater than a threshold, the antenna circuit is controlled to be in the second operating state; When the signal strength of the first antenna is less than a threshold, the antenna circuit switches from the second operating state to the first operating state.

9. The antenna circuit according to claim 8, characterized in that, The antenna circuit also includes a second power supply for powering the operational amplifier, the operational amplifier being connected to the second power supply via a second switching device; When the signal strength of the first antenna is less than a threshold, the second switching device is controlled to close. If the signal strength of the first antenna is greater than a threshold, the second switching device is controlled to disconnect.

10. An electronic device, characterized in that, The antenna circuit includes any one of claims 1 to 9.

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