Electronic device and method of operating the same

Abstract

A wearable device and an operating method thereof are provided. The wearable device includes an antenna element, a first matching circuit, a second matching circuit, and a switching element. The first matching circuit has a first impedance value. The second matching circuit has a second impedance value different from the first impedance value. The switching element is configured to determine whether the antenna element is electrically connected with the first matching circuit or the second matching circuit.

Description

Technical Field

[0001] This disclosure relates to an electronic device and a method of operating the same, and more particularly, to a wearable device including an antenna and a method of operating the same. Background Technology

[0002] With the emergence of more wireless communication technologies, wearable devices have become very popular. The transmission efficiency of wireless communication depends on the impedance matching between the antenna and the circuitry of the wearable device. The external environment is crucial in impedance matching. However, current wearable devices cannot provide good impedance matching in various environments. Summary of the Invention

[0003] In some embodiments, a wearable device includes an antenna element, a first matching circuit, a second matching circuit, and a switching element. The first matching circuit has a first impedance value. The second matching circuit has a second impedance value different from the first impedance value. The switching element is configured to determine whether the antenna element is electrically connected to the first matching circuit or the second matching circuit.

[0004] In some embodiments, a method of operating an antenna module includes: generating a control signal; and determining, in response to the control signal, whether the antenna is electrically connected to a first matching circuit or a second matching circuit. The first matching circuit has an impedance value different from that of the second matching circuit. Attached Figure Description

[0005] Some aspects of embodiments of this disclosure will be readily understood from the following detailed description when read in conjunction with the accompanying drawings. It should be noted that the various structures may not be drawn to scale, and the dimensions of the various structures may be arbitrarily increased or decreased for clarity of explanation.

[0006] Figure 1 A block diagram illustrating an electronic device according to some embodiments of the present disclosure is shown.

[0007] Figure 2A and 2B Simulation results of an electronic device according to some embodiments of the present disclosure are illustrated.

[0008] Figure 3 A schematic diagram of a matching circuit according to some embodiments of the present disclosure is shown.

[0009] Figure 4 A block diagram illustrating an electronic device according to some embodiments of the present disclosure is shown.

[0010] Figure 5 A flowchart illustrating a method of operating an electronic device according to some embodiments of the present disclosure is shown. Detailed Implementation

[0011] Common reference numerals are used throughout the accompanying drawings and detailed descriptions to indicate the same or similar components. Embodiments of this disclosure will be readily understood from the following detailed description taken in conjunction with the accompanying drawings.

[0012] The following disclosure provides numerous different embodiments or instances for implementing various features of the provided subject matter. Specific examples of components and arrangements are described below to illustrate certain aspects of this disclosure. Of course, these components and arrangements are merely examples and are not intended to be limiting. For example, in the following description, embodiments may include a first feature formed on or on a second feature, where the first and second features are formed or disposed in direct contact, and embodiments may also include additional features formed or disposed between the first and second features such that the first and second features are not in direct contact. Furthermore, reference numerals and / or letters may be repeated in various instances of this disclosure. This repetition is for simplicity and clarity and does not, in itself, define a relationship between the various embodiments and / or configurations discussed.

[0013] Figure 1 A block diagram of an electronic device 1 according to some embodiments of the present disclosure is illustrated. In some embodiments, the electronic device 1 may be an antenna module or a wearable device (e.g., an electronic watch, electronic band, electronic glasses, headphones, or the like) or a part thereof. As shown, the electronic device 1 includes an antenna element 11, a switching element 12, a detection element 13, matching circuits 14 and 15, and a processing element 16.

[0014] Antenna element 11 can be electrically connected to matching circuit 14. Antenna element 11 can be electrically connected to matching circuit 15. Switching element 12 can be electrically connected to matching circuit 14. Switching element 12 can be electrically connected to matching circuit 15. Detection element 13 can be electrically connected to switching element 12. Processing element 16 can be electrically connected to switching element 12.

[0015] Antenna element 11 may be configured to receive electromagnetic waves from one or more external devices. Antenna element 11 may be configured to transmit electromagnetic waves to external devices. For example, antenna element 11 may be configured to provide a wireless connection between electronic device 1 and an external device. Antenna element 11 may be further configured to provide one or more electrical signals (e.g., current) to processing element 16 via a matching circuit (e.g., matching circuit 14 or matching circuit 15) and switching element 12 in response to electromagnetic waves received from external devices. Antenna element 11 may be configured to receive one or more electrical signals (e.g., current) from processing element 16 via a matching circuit (e.g., matching circuit 14 or matching circuit 15) and switching element 12. Antenna element 11 may be configured to radiate the energy of one or more received electrical signals as electromagnetic waves. In some embodiments, antenna element 11 may include a feed portion configured to receive and / or transmit electrical signals. The feed portion may have a terminal connected to ground. In some embodiments, antenna element 11 may include a monopole antenna, a chip antenna, or the like.

[0016] Detection element 13 can be configured to detect the presence of an external object in the vicinity of electronic device 1. The external object may include, for example, a user's finger, head, or other body part. The external object may contain, for example, tissue fluid or a conductive fluid. Detection element 13 can be configured to sense contact between the external object and electronic device 1. Detection element 13 can be configured to determine whether the distance between the external object and electronic device 1 is less than or equal to a threshold distance. Detection element 13 can be a sensing element. Sensing elements may include, for example, resistive sensors, capacitive sensors, inductive sensors, optical sensors (e.g., infrared sensors), sound sensors, or proximity sensors.

[0017] The detection element 13 is configured to generate a signal (or control signal) depending on the detection result and send the signal to the switching element 12. For example, the detection element 13 may be configured to generate a signal with a first logic value when an external object is detected as being near the electronic device 1. For example, the detection element 13 may be configured to generate a signal with a second logic value when no external object is detected (or does not exist). The first logic value is different from the second logic value.

[0018] Switching element 12 is configured to receive a signal from detection element 13. Switching element 12 may be configured to determine whether antenna element 11 is electrically connected to matching circuit 14 or matching circuit 15 based on the signal received from detection element 13. In some embodiments, when a connection is established between antenna element 11 and matching circuit 14, the connection between antenna element 11 and matching circuit 15 is severed, and vice versa. In some embodiments, switching element 12 may comprise, for example, an electrical switch or a mechanical switch.

[0019] Matching circuit 14 may have a first impedance value. Matching circuit 15 may have a second impedance value different from the first impedance value of matching circuit 14. In some embodiments, the first impedance value may be greater than the second impedance value. Alternatively, the first impedance value may be less than the second impedance value. When switching element 12 connects antenna element 11 to matching circuit 14, matching circuit 14 may be electrically coupled to antenna 11, for example, the feed portion of antenna 11. When switching element 12 connects antenna element 11 to matching circuit 15, matching circuit 15 may be electrically coupled to antenna 11, for example, the feed portion of antenna 11. Matching circuit 15 is disconnected from matching circuit 14.

[0020] Processing element 16 is configured to receive one or more electrical signals (e.g., current) from antenna 11 via switching element 12 and matching circuit 14 or matching circuit 15. Processing element 16 may provide one or more electrical signals (e.g., current) to antenna 11. Processing element 16 may include, for example, a transmitter, receiver, processor, multiplexer, memory, and the like. In some embodiments, processing element 16 may control a speaker, microphone, or display (not shown).

[0021] Antenna element 11 may have a predetermined impedance value. The predetermined impedance value may be in the range of about 30 ohms to about 75 ohms. The predetermined impedance value may be about 50 ohms. Matching the predetermined impedance value of antenna element 11 with the impedance value of the load terminals of the circuitry of electronic device 1 (e.g., the transmitter or receiver of processing element 16) is extremely critical for wireless transmission efficiency. Impedance matching causes a change in the resonant frequency of antenna 11. If the resonant frequency of antenna element 11 is within a desirable frequency band, then the wireless transmission efficiency can be higher, i.e., the return loss of antenna element 11 (e.g., parameter S11) can be reduced. The desirable frequency band can indicate the frequency of electromagnetic waves transmitted and / or received by antenna element 11. In some embodiments, the desirable frequency band may be in the range of about 2.4 GHz to about 2.5 GHz. Therefore, using a matching circuit can create better impedance matching between antenna element 11 and the terminals of the circuitry of electronic device 1.

[0022] In a comparative embodiment, the electronic component may include only one matching circuit, and good impedance matching between the antenna element and the matching circuit can be achieved when the electronic component is placed in an environment free of external objects. However, when the electronic device is in contact with or near an external object, the equivalent impedance of the antenna element will change, and impedance mismatch will occur between the antenna element and the matching circuit, which will adversely affect the radiation performance of the antenna element. For example, if good impedance matching between the antenna element and the matching circuit is achieved, the antenna element can operate at its resonant frequency within a desired frequency band. For example, such as... Figure 2AThe example transmission efficiency data for the antenna elements shown illustrate that the return loss (e.g., the S11 parameter at 2.4 GHz, 2.45 GHz, and 2.5 GHz) is better than a specific decibel value within the desired frequency band. However, if impedance mismatch occurs between the antenna element and the matching circuit, the antenna element will operate at a resonant frequency outside the desired frequency band (e.g., frequency shift), which will increase the return loss of the antenna element and reduce its transmission efficiency. For example, as... Figure 2B The example transmission efficiency data for the antenna elements shown illustrates that return loss (e.g., S11 parameters at 2.4 GHz, 2.45 GHz, and 2.5 GHz) is inferior to a specific decibel value (e.g., -10 dB) within the desired frequency band. This results in shorter transmission distances, higher transmission power, and higher latency.

[0023] According to such Figure 1 In the embodiment shown, electronic device 1 has two or more matching circuits 14, 15, and switching element 12 can determine that antenna element 11 is electrically connected to matching circuit 14 or matching circuit 15 based on a signal from detection element 13. Therefore, electronic device 1 can ensure impedance matching between antenna element 11 and matching circuits (e.g., matching circuit 14 or matching circuit 15) in different environments. For example, if no external object is present, the impedance value of antenna element 11 can be matched to the impedance value of the circuit system of electronic device 1 via matching circuit 14. Antenna element 11 may have a first resonant frequency within a desired frequency band. For example, if an external object is detected as approaching electronic component 1, the impedance value of antenna element 11 can be matched to the impedance value of the circuit system of electronic device 1 via matching circuit 15. Antenna element 11 may have a second resonant frequency within a desired frequency band. Although the first resonant frequency may differ from the second resonant frequency, both are within the desired frequency band. Therefore, regardless of changes in the environment, the antenna element 11 of the electronic device 1 can operate at a resonant frequency (e.g., a first resonant frequency or a second resonant frequency) within a desirable frequency band, which will improve the transmission efficiency of the antenna element 11 (e.g., longer transmission distance, lower transmission power, and lower delay).

[0024] In other words, when electronic device 1 is positioned in free space where no external objects are present, antenna element 11 of electronic device 1 will generate a first resonant frequency. During the transient period when an external object approaches electronic device 1 within a threshold distance, before the switch 12 of electronic device 1 switches from matching circuit 14 to matching circuit 15, antenna element 11 may generate a third resonant frequency different from the first frequency. The third resonant frequency may be outside the desired frequency band. After the matching circuit 15 establishes a connection with antenna element 11, antenna element 11 will generate a second resonant frequency.

[0025] In some comparative embodiments, the electronic device may include multiple antennas to maintain transmission efficiency by switching one of the antennas to another. However, multiple antennas occupy a large volume, which is unsuitable for some applications (e.g., wearable devices). In this disclosure, the electronic device 1 controls antenna impedance matching by switching between multiple small matching circuits (e.g., matching circuit 14 and matching circuit 15, or more). Therefore, the size of the electronic device 1 can be reduced.

[0026] Figure 3 A schematic diagram of a matching circuit (e.g., matching circuit 14) according to some embodiments of the present disclosure is illustrated. As shown, matching circuit 14 may include a first terminal 141, a second terminal 142, and electronic components 143, 144, and 145. The first terminal 141 may be electrically coupled to the antenna element 11 when the switching element 12 connects the first terminal 141 to the antenna element 11. The second terminal 142 may be electrically connected to a processing element 16, such as a transmitter or receiver of the processing element 16.

[0027] Electronic component 143 may have a terminal electrically connected to a first terminal 141. Electronic component 143 may have a terminal electrically connected to electronic component 144. Electronic component 143 may have a terminal electrically connected to ground. Electronic component 144 may have a terminal electrically connected to the first terminal 141. Electronic component 144 may have a terminal electrically connected to a second terminal 142. Electronic component 144 may have a terminal electrically connected to electronic component 145. Electronic component 145 may have a terminal electrically connected to the second terminal 142. Electronic component 145 may have a terminal electrically connected to ground. Electronic components 143, 144, and 145 may each include, for example, a capacitor, a resistor, an inductor, or a combination thereof. In some embodiments, electronic components 143, 144, or 145 may include an inductor having an inductance value of about 1 nanohenry (nH) to about 7 nH. In some embodiments, electronic components 143, 144, or 145 may include an inductor having an inductance value of about 3 nH to about 5 nH.

[0028] Matching circuit 15 may have a similar configuration to matching circuit 14, except that the equivalent impedance value of matching circuit 15 differs from that of matching circuit 14. For example, matching circuit 15 may include a first inductor and a second inductor. The inductance value of the first inductor may differ from that of the second inductor.

[0029] In some embodiments, the electronic components of the matching circuit (e.g., matching circuit 14 or matching circuit 15) can be determined via a Smith chart. With a Smith chart, the equivalent impedance of the matching circuit and circuitry of the electronic device (and external objects, if present) can be matched to a predetermined impedance value (e.g., 50 ohms) of the antenna element by adjusting the impedance values ​​of the electronic components of the matching circuit (including inductors, capacitors, or a combination of inductors and capacitors).

[0030] Figure 4 A schematic diagram of an electronic device 2 according to some embodiments of the present disclosure is shown in FIG2. The electronic device 2 in FIG2 is... Figure 1 The electronic device 2 is similar to that of the electronic device 1, except that the switching element 12 and the matching circuits 14 and 15 are integrated into the integrated circuit 20. Therefore, the size of the electronic device 2 can be further reduced.

[0031] Figure 5 A flowchart illustrating a method of operating an electronic device (e.g., electronic device 1 or electronic device 2) according to some embodiments of the present disclosure is shown.

[0032] Step 303 includes determining the presence of an external object near the electronic device using a detection element (e.g., detection element 13). Step 303 may further include detecting the presence of an external object near the electronic device by the detection element and generating a control signal based on the detection result. Step 303 may further include determining, in response to the control signal, whether an antenna element (e.g., antenna element 11) is electrically connected to a matching circuit or to another matching circuit (e.g., matching circuit 14 or matching circuit 15). The matching circuit may have an impedance value different from that of the other matching circuit. In some embodiments, if the external object is not present near the electronic device, the control signal may have a first logic value, and if the external object is present, the control signal may have a second logic value. The first logic value may be different from the second logic value. If no external object is detected, the operation may proceed to step 305. If an external object is detected, the operation may proceed to step 309.

[0033] Step 305 includes connecting the antenna to a matching circuit (e.g., matching circuit 14) using a switching element (e.g., switching element 12). In some embodiments, connecting the antenna to the matching circuit includes connecting the antenna to the matching circuit when the switching element receives a control signal having a first logic value.

[0034] Step 307 involves generating a first resonant frequency using antenna elements. The first resonant frequency may be within a desired frequency band.

[0035] Step 309 includes connecting the antenna to another matching circuit (e.g., matching circuit 15) using a switching element (e.g., switching element 12). In some embodiments, connecting the antenna to the other matching circuit includes connecting the antenna to the other matching circuit when the switching element receives a control signal having a second logic value.

[0036] Step 311 includes generating a second resonant frequency by the antenna elements. The second resonant frequency may be substantially within a desired frequency band. The first resonant frequency is different from the second resonant frequency. Furthermore, step 311 may further include generating a third resonant frequency, different from the first resonant frequency, before generating the second resonant frequency when the distance between the antenna module and an external object is equal to or less than a threshold distance.

[0037] By executing such Figure 5 The method demonstrated allows the antenna element of an electronic device to operate at a resonant frequency (e.g., a first or second resonant frequency) within a desired frequency band, regardless of changes in the environment. Good transmission efficiency can be maintained under various conditions, such as return loss, which will improve the transmission efficiency of the antenna element (e.g., longer transmission distance, lower transmission power, and lower delay).

[0038] As used herein, the terms “approximately,” “generally,” “roughly,” and “about” are used to describe and account for small variations. When used in conjunction with an event or situation, the terms may refer to examples where the event or situation occurred precisely, or examples where the event or situation approximately occurred. For example, when used in conjunction with numerical values, the terms may refer to a range of variation less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, if the difference between two numerical values ​​is less than or equal to ±10% of the average of the values, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%, then the values ​​may be considered “generally” the same or equal.

[0039] If the displacement between two surfaces is no greater than 5 μm, 2 μm, 1 μm, or 0.5 μm, then the two surfaces can be considered coplanar or approximately coplanar.

[0040] Unless the context clearly specifies otherwise, as used herein, the singular terms “a / an” and “the” may include multiple indicators.

[0041] As used herein, the terms “conductivity,” “electrical conductivity,” and “conductivity” refer to the ability to conduct electric current. Conductive materials generally indicate those that exhibit little or no obstruction to the flow of electric current. One measure of conductivity is Siemens per meter (S / m). Typically, conductive materials are those with a conductivity greater than about 10⁴ S / m, for example, at least 10⁵ S / m or at least 10⁶ S / m. The conductivity of a material can sometimes vary with temperature. Unless otherwise specified, the conductivity of a material is measured at room temperature.

[0042] In addition, quantities, ratios, and other values ​​are sometimes presented in range format in this document. It should be understood that such range format is for convenience and brevity and should be flexibly interpreted as including not only the values ​​explicitly specified as the limits of the range, but also all individual values ​​or subranges covered within the range, as if each value and subrange were explicitly specified.

[0043] Although this disclosure has been described and illustrated with reference to specific embodiments thereof, such descriptions and illustrations are not intended to be limiting. Those skilled in the art will understand that various changes and alternatives may be made without departing from the true spirit and scope of this disclosure as defined by the appended claims. Illustrations may not be drawn to scale. Differences between the process reproductions in this disclosure and actual equipment may exist due to manufacturing processes and tolerances. Other embodiments of this disclosure may exist that are not specifically described. This specification and the accompanying drawings should be considered illustrative rather than limiting. Modifications may be made to adapt particular circumstances, materials, compositions, methods, or processes to the objectives, spirit, and scope of this disclosure. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a particular order, it should be understood that these operations may be combined, subdivided, or reordered to form equivalent methods without departing from the teachings of this disclosure. Therefore, unless specifically indicated herein, the order and grouping of operations are not limitations of this disclosure.

Claims

1. A wearable device comprising: Antenna elements; A first matching circuit having a first impedance value; The second matching circuit has a second impedance value that is different from the first impedance value; and A switching element, configured to determine whether the antenna element is electrically connected to the first matching circuit or the second matching circuit. The antenna element has a first resonant frequency when electrically connected to the first matching circuit, and a second resonant frequency when electrically connected to the second matching circuit. The first resonant frequency and the second resonant frequency are within a desired frequency band. The antenna element temporarily has a third resonant frequency when electrically connected to the first matching circuit and about to switch to electrical connection with the second matching circuit. The third resonant frequency is different from the first resonant frequency and the second resonant frequency.

2. The wearable device of claim 1, further comprising a detection element electrically connected to the switching element, configured to determine whether the distance between an external object and the wearable device is less than or equal to a threshold distance.

3. The wearable device of claim 2, wherein the switching element is configured to connect the antenna element to the first matching circuit when the distance between the external object and the wearable device is greater than the threshold distance; and to connect the antenna element to the second matching circuit when the distance between the external object and the wearable device is less than or equal to the threshold distance.

4. The wearable device according to claim 2, wherein the third resonant frequency is temporarily generated when the distance is less than or equal to a threshold distance.

5. The wearable device of claim 2, wherein the detection element comprises an infrared sensor.

6. The wearable device according to claim 1, wherein the return loss at the first resonant frequency and the second resonant frequency is less than the return loss at the third resonant frequency.

7. The wearable device according to claim 1, wherein the first resonant frequency is different from the second resonant frequency, and wherein the third resonant frequency is outside the desired frequency band.

8. The wearable device of claim 2, wherein the third resonant frequency is generated before switching from the first matching circuit to the second matching circuit when the external object approaches the wearable device within the threshold distance.

9. The wearable device of claim 1, further comprising a processing element connected to the first matching circuit and the second matching circuit, configured to receive an electrical signal associated with the third resonant frequency at different times, wherein the processing element is configured to control a speaker, microphone, or display of the wearable device.

10. The wearable device of claim 1, further comprising a detection element and a processing element, wherein the detection element is electrically connected to the switching element and configured to determine whether the distance between an external object and the wearable device is less than or equal to a threshold distance, and generates a control signal based on the detection result and sends the control signal to the switching element; in, When the external object is detected to be near the wearable device, the control signal has a first logic value; when the external object is not detected, the control signal has a second logic value that is different from the first logic value. The switching element is configured to receive the control signal from the detection element and determine, based on the control signal, whether the antenna element is electrically connected to the first matching circuit or the second matching circuit; The processing element is electrically connected to the switching element and configured to receive electrical signals from or provide electrical signals to the antenna element via the switching element and the first matching circuit or the second matching circuit. The antenna element has a predetermined impedance of approximately 50 ohms, and the desired frequency band of the electromagnetic waves transmitted and / or received by the antenna element is 2.4 GHz to 2.5 GHz. The electronic components of the first matching circuit and the second matching circuit are configured to match the equivalent impedance value of the matching circuit and circuit system of the wearable device with the predetermined impedance value of the antenna element. The first matching circuit includes a first terminal, a second terminal, a first electronic component, a second electronic component, and a third electronic component. The first terminal is electrically coupled to the antenna element when the switching element connects the first terminal to the antenna element. The second terminal is electrically connected to the processing element. The first electronic component is electrically connected to the first terminal, the second electronic component, and ground. The second electronic component is electrically connected to the first terminal, the second terminal, and the third electronic component. The third electronic component is electrically connected to the second terminal and ground. At least one of the first electronic component, the second electronic component, and the third electronic component includes an inductor with an inductance value of 3 nH to 5 nH.

11. The wearable device of claim 10, wherein when impedance matching is achieved between the antenna element and the circuitry of the wearable device, the S11 parameter of the antenna element at 2.4 GHz, 2.45 GHz, and 2.5 GHz is less than or equal to −10 dB, and when the distance between the antenna element and the external object is equal to or less than a threshold distance, during the transient period before the switching element switches the antenna element from the first matching circuit to the second matching circuit, the antenna element generates the third resonant frequency, which is different from the first resonant frequency and located outside the desired frequency band, and generates the second resonant frequency after the second matching circuit establishes a connection with the antenna element.

12. The wearable device of claim 2, wherein the detection element is not integrated with the antenna element, wherein the first matching circuit and the second matching circuit are integrated in a single integrated circuit, and the detection element is not integrated within the integrated circuit, the first resonant frequency and the second resonant frequency are different from each other, the return loss of the antenna element in the operating range of 2.4 GHz to 2.5 GHz is less than or equal to −10 dB, wherein the first matching circuit includes a first inductor, a capacitor, and a second inductor, the capacitor having a first terminal and a second terminal, and each of the first inductor and the second inductor having one end electrically connected to ground and the other end electrically connected to the first terminal and the second terminal of the capacitor, respectively.

13. The wearable device of claim 1, wherein the first matching circuit comprises a first inductor, a capacitor, and a second inductor, the capacitor having a first terminal and a second terminal, the first inductor and the second inductor each having one end electrically connected to ground and the other end electrically connected to the first terminal and the second terminal of the capacitor, respectively, wherein the inductance value of the first inductor is different from the inductance value of the second inductor.

14. The wearable device of claim 13, wherein the second matching circuit includes a third inductor and a fourth inductor, wherein the inductance value of the third inductor is different from the inductance value of the fourth inductor, wherein the first inductor, the second inductor, the third inductor and the fourth inductor each have an inductance value of 3 nH to 5 nH.

15. A method of operating an antenna module, comprising: Generate control signals; In response to the control signal, it is determined whether the antenna element is electrically connected to the first matching circuit or the second matching circuit. The first matching circuit has an impedance value that is different from that of the second matching circuit; If the antenna element is electrically connected to the first matching circuit, then a first resonant frequency is generated; If the antenna element is electrically connected to the second matching circuit, then a second resonant frequency is generated, wherein the first resonant frequency and the second resonant frequency are within the desired frequency band; and When the antenna element is electrically connected to the first matching circuit and is about to switch to electrical connection with the second matching circuit, it temporarily generates a third resonant frequency, wherein the third resonant frequency is different from the first resonant frequency and the second resonant frequency.

16. The method of claim 15, further comprising determining whether the distance between the external object and the antenna module is less than or equal to a threshold distance.

17. The method of claim 15, wherein the return loss at the first resonant frequency and the second resonant frequency is less than the return loss at the third resonant frequency.

18. The method of claim 15, wherein the first resonant frequency is different from the second resonant frequency, and wherein the third resonant frequency is outside the desired frequency band.

19. The method of claim 16, wherein when the external object approaches the antenna module within the threshold distance, the third resonant frequency is generated before switching from the first matching circuit to the second matching circuit.

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