Device with a slot antenna

Abstract

The present disclosure relates to the technical field of electronic devices, and specifically provides a device with a slot antenna, including: a radiation slot formed on the device; a feeding terminal, one end of which straddles the slot and is connected to the feeding point of the slot antenna, and the other end of which is electrically connected to the radio frequency unit of the device; a first inductor, one end of which straddles the slot and is connected to the grounding point of the slot antenna, and the other end of which is electrically connected to the grounding unit of the device; and a first capacitor, disposed in the slot and two electrodes of the first capacitor are respectively connected to two ends in the width direction of the slot, and in the length direction of the slot, the first capacitor is located between the feeding terminal and the first inductor. The antenna of the present disclosure can meet the working requirements of a multi-band antenna, and a multi-band slot antenna can be realized on a device with a small volume.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electronic devices, and particularly to a device with a slot antenna. Background Art

[0002] With the development of electronic devices, more and more functions can be achieved by intelligent wearable devices. Taking a smart watch as an example, it has functions such as motion assistance, satellite positioning, wireless connection, and call, and these functions all need to rely on the antenna built in the watch to be realized.

[0003] In order to pursue the aesthetic feeling and texture of the device appearance, more and more intelligent wearable devices adopt metal materials and at the same time adopt a slot antenna structure to realize the antenna function. For wearable devices, their volume is often small, and the design space of the antenna is limited, making it difficult to meet the antenna functions of multiple frequency bands. Taking a smart watch as an example, due to the volume limitation of the watch, it is difficult to use a slot antenna to realize the design of a dual-band GPS antenna in related technologies. Summary of the Invention

[0004] To solve the technical problem of the multi-band antenna design of electronic devices, an embodiment of the present disclosure provides a device with a slot antenna.

[0005] An embodiment of the present disclosure provides a device with a slot antenna, including:

[0006] A radiation slot formed on the device;

[0007] A feeding terminal, one end of which straddles the slot and is connected to the feeding point of the slot antenna, and the other end is electrically connected to the radio frequency unit of the device;

[0008] A first inductor, one end of which straddles the slot and is connected to the grounding point of the slot antenna, and the other end is electrically connected to the grounding unit of the device; and

[0009] A first capacitor, disposed in the slot and two electrodes of the first capacitor are respectively connected to both ends in the width direction of the slot, and in the length direction of the slot, the first capacitor is located between the feeding terminal and the first inductor.

[0010] In some embodiments, the operating frequency of the slot antenna includes at least two resonant frequencies, and the first capacitor and the first inductor are used to adjust at least one of the resonant frequencies of the operating frequency.

[0011] In some embodiments, the operating frequency of the slot antenna includes a first resonance and a second resonance, the first resonance is the second-order resonant frequency of the slot antenna, and the second resonance is the third-order resonant frequency of the slot antenna.

[0012] In some embodiments, the operating frequency of the slot antenna includes a first resonance and a second resonance. The frequency band of the first resonance includes the L5 frequency band of the GPS satellite positioning system, and the frequency band of the second resonance includes the L1 frequency band of the GPS satellite positioning system.

[0013] In some embodiments, the operating frequency of the slot antenna further includes a third resonance, and the frequency band of the third resonance includes the Bluetooth / WiFi operating frequency band.

[0014] In some embodiments, the third resonance is the fourth-order resonance frequency of the slot antenna.

[0015] In some embodiments, the operating frequency of the slot antenna includes two resonance frequencies. In the length direction of the slot, the first capacitor is located at a position where the voltage value of one of the resonance frequencies is zero and the voltage value of the other resonance frequency is non-zero.

[0016] In some implementation manners, in the length direction of the slot, the first capacitor is located at a position where the voltage value of the second resonance is zero and the voltage value of the first resonance is non-zero.

[0017] In some embodiments, the slot antenna is a half-wavelength slot antenna.

[0018] In some embodiments, the device further includes: a main board, including the grounding unit and the radio frequency unit.

[0019] In some embodiments, the device further includes: a first conductor, which is disposed opposite to the main board at an interval, so that the interval between the first conductor and the main board forms the slot.

[0020] In some embodiments, the device further includes: a second conductor, which is electrically connected to the grounding unit, and the slot is formed on the second conductor.

[0021] In some embodiments, the device is a mobile terminal.

[0022] In some embodiments, when the device includes a first conductor, the mobile terminal includes: a conductive middle frame, which forms the first conductor, and the middle frame is disposed around the outside of the main board at an interval, and the interval between the middle frame and the main board forms the slot.

[0023] In some embodiments, when the device includes a second conductor, the mobile terminal includes: a conductive housing, which forms the second conductor, the main board is disposed inside the housing, the grounding module of the main board is electrically connected to the housing, and the slot is formed on the housing.

[0024] In some embodiments, the mobile terminal includes a wrist-worn device.

[0025] The device according to the embodiments of the present disclosure includes a slot formed on the device, a feeding terminal and a first inductor bridging both ends in the length direction of the slot. The feeding terminal is connected to the radio frequency unit of the device to form an excitation source of the antenna. The first inductor is connected to the grounding unit of the device, that is, it returns to the ground through the first inductor, thereby increasing the effective electrical length of the slot antenna. At the same operating frequency, the required slot length of the antenna is shorter, reducing the occupation of the device space by the antenna slot. A first capacitor is provided between the feeding terminal and the first inductor. By adjusting the regional position of the voltage distribution relationship of the first capacitor at the multi-order resonance frequency, the adjustment of the multiple frequency relationship of the multi-order resonance can be realized, and the multi-order resonance frequency can be adjusted to an available operating frequency, and the operating requirements of multiple frequencies can be realized by using one antenna structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific embodiments of the present disclosure or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present disclosure. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0027] Figure 1 is an exploded view of the structure of a terminal device according to some embodiments of the present disclosure.

[0028] Figure 2 is a schematic diagram of the principle of a dual-band slot antenna according to some embodiments of the present disclosure.

[0029] Figure 3 is a schematic diagram of the current distribution at the first-order resonance frequency of the antenna according to some embodiments of the present disclosure.

[0030] Figure 4 is a schematic diagram of the current distribution at the second-order resonance frequency of the antenna according to some embodiments of the present disclosure.

[0031] Figure 5 is a schematic diagram of the current distribution at the third-order resonance frequency of the antenna according to some embodiments of the present disclosure.

[0032] Figure 6 is a curve graph of the change in the S parameters of the antenna with the first capacitor applied at the voltage zero point position.

[0033] Figure 7 is a schematic diagram of the current distribution of the antenna at the second-order resonance frequency after the first capacitor is applied at the voltage zero point position.

[0034] Figure 8 It is a curve graph showing the variation of the S-parameters of the antenna with the first inductor after applying the first capacitor.

[0035] Figure 9 It is the S-parameter curve graph of the antenna according to a specific embodiment of the present disclosure.

[0036] Figure 10 It is the efficiency curve graph of the antenna according to a specific embodiment of the present disclosure.

[0037] Figure 11 It is a schematic structural diagram of the antenna according to another embodiment of the present disclosure.

[0038] Figure 12 It is a schematic structural diagram of the antenna according to still another embodiment of the present disclosure. Specific Embodiment

[0039] The technical solutions of the present disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present disclosure. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present disclosure without creative efforts shall fall within the protection scope of the present disclosure. In addition, the technical features involved in different embodiments of the present disclosure described below can be combined with each other as long as they do not conflict with each other.

[0040] A slot antenna refers to an antenna formed by opening a slot on a conductor surface. A typical slot antenna can form a long strip-shaped slot through the device PCB (Printed Circuit Board) and a metal middle frame, or open a long strip-shaped slot on a metal shell, and the feed across the slot serves as the excitation source of the antenna.

[0041] The working principle of a slot antenna is similar to that of a dipole antenna. Generally, the length of the slot is 1 / 2 of the wavelength of the first-order resonance frequency of the antenna, that is, there is the following relationship between the slot length L of the slot antenna and the wavelength λ of the antenna operating frequency:

[0042]

[0043] In formula (1), C is the speed of light and f is the first-order resonance frequency. It can be seen from formula (1) that the slot length L is inversely proportional to the operating frequency f of the antenna, that is, the lower the operating frequency of the antenna, the longer the required slot length.

[0044] Taking the GPS satellite positioning system as an example, the civilian frequency bands of the GPS satellite positioning system include the L1 band and the L5 band. The center frequency of L1 is 1.575 GHz, and the center frequency of L5 is 1.176 GHz. Since the satellite coverage rate of the L1 band is relatively large, L1 is usually used as the basic GPS operating frequency band. A single-frequency GPS antenna is an antenna that only supports the L1 band. A dual-frequency GPS means that it supports both the L1 and L5 bands at the same time. The L1 band is used as the basic band, and the L5 band is used as an auxiliary band for L1, so as to eliminate the ionospheric error and greatly improve the positioning accuracy.

[0045] It can be calculated from Equation (1) that the half-wavelength of the L1 wave of the GPS satellite positioning system in free space is about 95 mm, while the half-wavelength of the L5 wave in free space is about 127 mm. For some terminal devices, such as a typical smart watch, due to the limited volume of the watch, it is impossible to make slot antennas for GPS L1 and L5 in the watch at the same time. Moreover, wearable devices often also require Bluetooth / WiFi antennas, which further compresses the internal space of the device. This results in some terminal devices being difficult to implement a dual-frequency GPS satellite positioning system, leading to a relatively low positioning accuracy of the device.

[0046] To solve the above technical problems, the embodiments of the present disclosure provide a device with a slot antenna. The device can be any device with a slot antenna structure, such as a handheld device like a smart phone or a tablet computer, or a wrist-worn device like a smart watch or a smart bracelet. The present disclosure does not limit this. The device of the embodiments of the present disclosure aims to utilize the multi-order resonant frequencies of the slot antenna to achieve the multiplexing of dual-frequency or more frequencies, and can realize a multi-frequency antenna structure in a relatively small device space. For example, the design of a dual-frequency GPS antenna can be realized within the existing volume of a watch or a bracelet. Therefore, the device of the present disclosure has better effects on terminal devices with a relatively small volume, such as wrist-worn devices. However, the device of the present disclosure is also applicable to any other device with a slot antenna and can achieve the same effect. The present disclosure does not limit this.

[0047] In some embodiments, the device of the present disclosure with a slot antenna includes: a slot formed on the device, and a feeding terminal and a first inductor connected across the slot. The slot can be a slot formed by the main board and the metal middle frame of the device, or a slot opened on the metal housing of the device. The present disclosure does not limit this.

[0048] One end of the feeding terminal is connected to the feeding point of the antenna across the slot, and the other end is connected to the radio frequency unit on the device main board, thereby serving as the excitation source of the antenna. One end of the first inductor is connected to the grounding point of the antenna across the slot, and the other end is connected to the grounding unit on the device main board. Thus, the first inductor serves as the ground return end of the antenna, that is, the slot between the feeding terminal and the first inductor is the radiation slot of the antenna. In the length direction of the slot, the first capacitor is arranged between the feeding terminal and the first inductor, and its two electrodes are respectively connected to both ends in the width direction of the slot, thereby using the first capacitor and the first inductor to adjust at least the first-order resonance frequency of the antenna.

[0049] The embodiment of the present disclosure lies in: by adding the first capacitor and the first inductor in the slot antenna, adjusting the multiple-frequency relationship of the multiple-order resonance frequencies of the slot antenna, so that the multiple-order resonance frequencies are adjusted to available operating frequencies, and the operating requirements of multiple frequency bands can be realized by using one antenna structure.

[0050] Based on the principle of the slot antenna, when the slot antenna is fed through the feeding terminal, the slot antenna can generate multiple-order resonance frequencies, and there is a multiple-frequency relationship between the multiple-order resonance frequencies. For a single-frequency antenna, usually only the first-order resonance mode (also called "fundamental mode") among the multiple-order resonance frequencies can be utilized. And the "multi-frequency antenna" described in the present disclosure means that for the same slot antenna structure, two or more orders of resonance frequencies can be utilized simultaneously.

[0051] For example, for the same slot antenna, if one of its resonance frequencies is 1.176 GHz and another resonance frequency is 1.575 GHz, then the GPS L1 and L5 antennas can be realized simultaneously by using this antenna. However, according to the above, there is a multiple-frequency relationship among the multiple-order resonances of the slot antenna. Taking the first three-order resonances as an example, if the first-order resonance frequency is f0, the second-order resonance frequency is 2f0, and the third-order resonance frequency is 3f0. This results in that in most cases, the multiple-order resonance frequencies cannot be directly utilized. For example, when the first-order resonance frequency of the slot antenna is 1.176 GHz, the second-order resonance frequency reaches 2.352 GHz, far exceeding 1.575 GHz of the GPS L1 frequency band.

[0052] Based on the above principle, in the embodiment of the present disclosure, the first capacitor and the first inductor can be used to adjust the multiple-frequency relationship of the multiple-order resonance frequencies of the slot antenna to make it meet the required target frequencies, and a multi-frequency antenna can be realized by using the same antenna structure, greatly simplifying the structure of the device antenna, which will make it possible for the antenna structure that could not be realized on a device with a small volume originally.

[0053] To facilitate an intuitive understanding of the present disclosure solution, the present disclosure solution will be described below in conjunction with a specific embodiment. In this embodiment, the device is taken as an example of a smart watch, and the slot antenna is taken as an example of a dual-band GPS antenna. As can be seen from the foregoing, in a smart watch, due to volume constraints, it is impossible to use a slot antenna structure to make a dual-band GPS antenna. This embodiment will describe the design for implementing a dual-band GPS antenna in a smart watch.

[0054] As Figure 1 shown, the smart watch of this embodiment includes a screen assembly 100, a metal middle frame 200, a device main board 300, a battery 400, and a bottom case 500. In this embodiment, the slot antenna is formed by feeding power and returning to ground through the slot between the device main board 300 and the metal middle frame 200. Figure 2 shows the structural schematic diagram of the slot antenna of this embodiment. Specifically, as Figure 2 shown, an annular slot 610 is formed between the device main board 300 and the middle frame 200. The feeding terminal 620 is bridged across the slot 610. One end of the feeding terminal 620 is connected to the middle frame 200 to form a feeding point, and the other end is connected to the radio frequency unit on the device main board 300. The first inductor 630 is bridged across the slot 610. One end of the first inductor 630 is connected to the middle frame 200 to form a ground return point, and the other end is connected to the grounding unit of the device main board 300. Thus, the slot antenna structure is formed between the feeding terminal 620 and the first inductor 630. It should be noted that the grounding unit of the device described in this embodiment refers to the PCB board of the device main board 300, and the PCB board is the ground of the entire system, which can be understood by those skilled in the art.

[0055] It can be understood that in this embodiment, instead of directly returning to ground at the antenna ground return point position, it returns to ground through the first inductor 630. According to the principle of the foregoing slot antenna, returning to ground through the first inductor 630 is equivalent to increasing the effective electrical length of the antenna, thereby causing the resonant frequency of the slot antenna to shift towards the low frequency.

[0056] Continuing to refer to Figure 2 , the first capacitor 640 is bridged across the slot 610. Specifically, one end electrode of the first capacitor 640 is connected to the middle frame 200, and the other end electrode is connected to the grounding unit of the device main board 300. Setting a capacitor in the slot antenna can also increase the effective electrical length of the antenna, thereby causing the resonant frequency of the slot antenna to shift towards the low frequency.

[0057] On this basis, continue to explore how to adjust two certain resonant frequencies of the slot antenna to the GPS L1 and L5 frequency bands.

[0058] First, considering that the center operating frequency of the GPS L1 band is 1.575 GHz and the center operating frequency of the L5 band is 1.176 GHz, the frequency doubling relationship between the two is approximately 1.34 times. Based on the foregoing, the frequency doubling relationship of the first three resonant frequencies of the slot antenna is f0, 2f0, and 3f0, and the frequency doubling relationship between the second and third resonant frequencies is 1.5 times, which is relatively close to the frequency doubling relationship between the L1 and L5 bands. Therefore, in this embodiment, the second and third resonant frequencies of the slot antenna are used to implement a dual-band GPS antenna. For ease of description, hereinafter, the second resonant frequency of the slot antenna is defined as the "first resonance", and the third resonant frequency is defined as the "second resonance".

[0059] It should be noted that in this embodiment, considering the actual volume of the smart watch, for a normal wrist watch volume, only the first three resonances are allowed to implement such a low-frequency antenna structure. On the basis of the first three resonances, the second and third resonances are adopted in this embodiment, which is more conducive to implementing a dual-band GPS antenna. However, those skilled in the art should understand that on the basis of the present disclosure concept, in the scenarios of other embodiments, the present disclosure solution can theoretically adjust any two or more resonant frequencies without being limited to the examples of this embodiment, and the present disclosure will not elaborate on this.

[0060] Secondly, on the basis of the foregoing, further explore the frequency influence of the first capacitor 640 on the first resonance and the second resonance. Figures 3 to 5 Shows the current distribution schematic diagram of the first three resonant frequencies of the antenna when the first capacitor 640 is not provided. In the figure, the darker the color, the denser the current distribution, and the lighter the color, the less the current distribution.

[0061] Figure 3 Shows the current distribution of the first resonant frequency of the slot antenna. It can be seen that in the direction from the feeding point A to the grounding point B, the current density gradually decreases first, and decreases to zero at the current zero point C, and then the current density gradually increases, that is, the first resonant frequency has a current zero point C. It should be noted that theoretically, if the slot 610 is a regular slot, the current zero point C of the first resonant frequency should be near the midpoint of the slot. Since the device main board 300 in this embodiment is irregular, the position of the current zero point C is slightly offset.

[0062] Similarly, Figure 4 Shows the current distribution of the second resonant frequency of the slot antenna. It can be seen that the second resonant frequency has two current zero points D1 and D2. Figure 5 Shows the current distribution of the third resonant frequency of the slot antenna. It can be seen that the third resonant frequency has three current zero points E1, E2, and E3. Through Figures 3 to 5The current distribution also proves that the third-order resonant frequencies have a multiple-frequency relationship of f0, 2f0, and 3f0.

[0063] The voltage distribution of the resonant frequency is exactly opposite to the current distribution, that is, the position of the current zero corresponds to the voltage peak, and the position of the current peak corresponds to the voltage zero. According to the working principle of the capacitor, when the voltage difference applied across the two electrodes of the capacitor is larger, the effect generated by the capacitor is stronger. Based on this, it can be known that if the first capacitor 640 is set at a position where the voltage value of a certain-order resonant frequency is zero, it will not have a frequency-lowering effect on this order of resonant frequency. Moreover, the position of the first capacitor 640 should satisfy that the stronger the voltage value at the position of the first capacitor 640, the greater the degree of low-frequency shift of this order of resonance.

[0064] Based on this rule, when adjusting the frequency of the first resonance, it should be ensured that the frequency of the second resonance is not affected or affected as little as possible. Therefore, in this embodiment, the position of the first capacitor 640 is at the voltage zero of the second resonance and the voltage of the first resonance is not zero.

[0065] Continue to refer to Figure 4 and Figure 5 It can be seen that in this embodiment, the current zeros D1 and D2 of the first resonance approximately correspond to the current peaks of the second resonance, that is, the voltage zero of the second resonance corresponds to the current zeros D1 and D2 of the first resonance. Therefore, the first capacitor 640 can be set at one of D1 and D2.

[0066] Figure 6 Shows the change curve of the S parameter (return loss) of the antenna when the first capacitor 640 is set at the D2 position. First, comparing the curve without applying the first capacitor 640 and the curve with the first capacitor 640 of 1.5 pF shows that the original frequency of the first resonance of the antenna is about 1.32 GHz. After applying a 1.5 pF capacitor at the D2 position, the frequency of the first resonance shifts to the low frequency to about 1.25 GHz, and at the same time, the second resonance frequency of the antenna hardly changes, which also proves the correctness of the above conclusion.

[0067] Furthermore, comparing the curves with a 1.5 pF capacitor and a 2.7 pF capacitor shows that the original frequency of the first resonance of the antenna is about 1.32 GHz. After applying a 1.5 pF capacitor at the D2 position, the frequency of the first resonance shifts to the low frequency to about 1.25 GHz. After applying a 2.7 pF capacitor at the D2 position, the frequency of the first resonance shifts to the low frequency to about 1.18 GHz, and at the same time, the second resonance of the antenna also hardly changes. Also referring to Figure 6 It can be seen that the S parameters of the antenna are all below -10 dB, with good antenna performance, fully meeting the requirements of the watch for the GPS satellite positioning system.

[0068] As described above, when using the first capacitor 640 to adjust the frequency of the first resonance, the following rules can be satisfied: the first capacitor 640 is arranged near the zero point of the second resonance voltage, so that the frequency of the first resonance can be independently adjusted without affecting the second resonance; moreover, the larger the capacitance value of the first capacitor 640, the stronger the effect of the frequency of the first resonance shifting towards the low frequency. Guided by this rule, those skilled in the art can undoubtedly achieve the adjustment of the first resonance.

[0069] Next, continue to explore the influence of the first inductor 630 on the antenna resonance frequency.

[0070] According to the foregoing principle, when the first inductor 630 is grounded, it is equivalent to increasing the effective electrical length of the slot antenna, so that the multi-order resonance frequencies of the antenna will all shift towards the low frequency. On this basis, in theory, the design of some dual-frequency slot antennas can already be achieved. However, the inventor of this case further studies and finds that the second resonance can also be independently adjusted through the first inductor 630, making it possible to realize the dual-frequency GPS antenna of the watch. The following is a hierarchical description.

[0071] First of all, as described above, the first resonance can be independently adjusted by using the first capacitor 640. Therefore, in the design of some dual-frequency slot antennas, the second resonance of the antenna can be first adjusted to the target frequency by applying the first inductor 630 to ground, and then the first resonance can be independently adjusted to the target frequency based on the above rules by using the first capacitor 640 to realize the design of the dual-frequency slot antenna.

[0072] However, it is difficult to achieve for a dual-frequency GPS antenna. For example, when the frequency of the second resonance is adjusted to around 1.575 GHz by the first inductor 630, the frequency of the first resonance may already be lower than 1.176 GHz, and the function of the first capacitor 640 is to shift the first resonance towards the low frequency. Therefore, the design of the dual-frequency GPS antenna may not be achieved. Based on this, the inventor of this case further studies the independent adjustment of the second resonance by the first inductor 630.

[0073] Figure 7Shows the current distribution of the first resonance after applying the first capacitor 640 at the D2 position. It can be seen that in the direction of the slot length from the feeding terminal 620 to the first capacitor 640, the current distribution is the same as described above, while in the slot length from the first capacitor 640 to the first inductor 630, there is almost little current distribution. Through research, the inventor of this case found that this is because: the application of the first capacitor 640 cuts off the current of the first resonance, so the current is concentrated on the left-side slot of the first capacitor 640, and only a small amount of current passes through the right-side slot of the first capacitor 640, and it satisfies that as the capacitance value of the first capacitor 640 increases, the current cutoff effect of the first capacitor 640 on the first resonance is stronger. Moreover, since the first capacitor 640 is located at the voltage zero point position of the second resonance, it has no influence on the current distribution of the second resonance.

[0074] On this basis, when changing the first inductor 630, since there is only a small amount of current distribution near the first inductor 630 for the first resonance, the first inductor 630 hardly affects the frequency change of the first resonance, and as the capacitance value of the first capacitor 640 increases, the influence of the first inductor 630 on the first resonance becomes smaller.

[0075] Figure 8 Shows the curve of the change of the first inductor 630 with respect to the S-parameters of the antenna when applying the first capacitor 640 with a capacitance of 1.5 pF at the D2 position. By comparing the curves of without inductor and 3.3 nH inductor, it can be seen that without using the first inductor 630 grounded, the frequency of the second resonance is about 1.9 GHz, while when using the 3.3 nH first inductor 630, the frequency of the second resonance shifts to the lower frequency to about 1.7 GHz, and the frequency of the first resonance hardly changes significantly.

[0076] Furthermore, for the curves of 3.3 nH inductor and 6.8 nH inductor, it can be seen that when using the 3.3 nH first inductor 630, the frequency of the second resonance shifts to the lower frequency to about 1.7 GHz, while when using the 6.8 nH first inductor 630, the frequency of the second resonance shifts to the lower frequency to about 1.6 GHz, and at the same time, the frequency of the first resonance also does not change significantly. And referring to Figure 8 it can be known that the S-parameters of the antenna are all below -10 dB, having good antenna performance and fully meeting the requirements of the watch for the GPS satellite positioning system.

[0077] As described above, when using the first inductor 630 to adjust the frequency of the second resonance, the following rules can be satisfied: By setting the first capacitor 640 near the zero point of the second resonance voltage, the frequency of the second resonance can be independently adjusted by grounding the first inductor 630 without affecting the first resonance; moreover, the greater the inductance value of the first inductor 630, the stronger the effect of the second resonance frequency shifting towards the low frequency. Guided by this rule, those skilled in the art can undoubtedly achieve the adjustment of the second resonance.

[0078] Based on all of the above, those skilled in the art can understand the principle of adjusting the frequencies of the first resonance and the second resonance of the antenna through the first capacitor 640 and the first inductor 630. The following will illustrate the design process of the dual-frequency GPS antenna in combination with specific embodiments.

[0079] First, within the space allowed by the watch, a typical slot antenna structure is designed such that the second-order resonance frequency of the slot antenna structure is as close as possible to and greater than 1.176 GHz, and the third-order resonance frequency is as close as possible to and greater than 1.575 GHz. Then, the first capacitor 640 is applied at the voltage zero point of the third-order resonance frequency. By adjusting the position and capacitance value of the first capacitor 640, the center operating frequency of the second-order resonance is adjusted to within the range near 1.176 GHz. At the antenna ground point, the first inductor 630 is grounded. By adjusting the inductance value of the first inductor 630, the center operating frequency of the third-order resonance is adjusted to within the range near 1.575 GHz, thereby realizing a dual-frequency GPS slot antenna.

[0080] Figure 9 Shows the S-parameter curve of the dual-frequency GPS slot antenna in this embodiment. Through Figure 9 As can be seen from the figure, the first resonance of the antenna structure in this embodiment can cover the GPS L5 center operating frequency band of 1.150 GHz to 1.2 GHz, and the second resonance can cover the GPS L1 center operating frequency band of 1.560 GHz to 1.620 GHz. At the same time, it can be seen that the antenna has good return loss. Figure 10 Shows the efficiency curve of the antenna in this embodiment. It can be seen that within the two GPS frequency bands, the total efficiency of the antenna in this embodiment is greater than 13%, which can meet the requirements of the wearable device for the performance of the dual-frequency GPS antenna.

[0081] As can be seen from the above, the device with a slot antenna in this embodiment uses the first capacitor and the first inductor to respectively adjust the two-order resonance frequencies of the antenna, thereby meeting the requirements of the dual-frequency GPS antenna using the same antenna structure. At the same time, the dual-frequency GPS antenna is realized by using the second-order resonance frequency and the third-order resonance frequency with a closer multiple-frequency relationship, which is more conducive to the design of the dual-frequency GPS antenna.

[0082] In the above embodiments, the structure and implementation principle of the slot antenna of the present disclosure are described by taking the dual-frequency GPS as an example. In fact, the slot antenna described in the present disclosure is not limited to the dual-frequency antenna, and an antenna design with more resonant frequencies in the operating frequency can also be realized.

[0083] In some embodiments, still taking the aforementioned smartwatch as an example, for a smartwatch, it often needs to establish a communication connection with a smartphone via Bluetooth or WiFi. Therefore, the Bluetooth / WiFi antenna is an essential antenna for the smartwatch. In this embodiment, considering that the center operating frequency of the Bluetooth / WiFi antenna is 2.4 GHz, which has an approximate double-frequency relationship with the GPS L5 band, and the double-frequency relationship between the third-order resonant frequency and the fourth-order resonant frequency of the slot antenna is 2 times.

[0084] Therefore, in this embodiment, in addition to the above-mentioned first resonance and second resonance, the slot antenna of the watch also includes a third resonance, and the third resonance is the fourth-order resonant frequency of the slot antenna. That is, the operating frequencies of the slot antenna include: the GPS L5 band realized by the first resonance, the GPS L1 band realized by the second resonance, and the Bluetooth / WiFi band realized by the third resonance. Thus, for a smartwatch, a dual-frequency GPS and a Bluetooth / WiFi antenna can be realized using the same slot antenna structure, without the need to separately set up a Bluetooth / WiFi antenna. Only the original radio frequency unit of the Bluetooth / WiFi needs to be connected to the dual-frequency GPS through a combiner, which simplifies the internal stacking design of the watch. For details not elaborated herein, those skilled in the art can implement them by referring to the foregoing and related technologies, and will not be elaborated herein.

[0085] The device of the present disclosure is to adjust the frequencies of two or more resonances through a first capacitor and a first inductor, so as to realize a dual-frequency GPS and a slot antenna for dual-frequency GPS and Bluetooth / WiFi. Based on this inventive concept, those skilled in the art can understand that the embodiments of the present disclosure are not limited to implementing the dual-frequency GPS antenna in the above embodiments, but can also be any other dual-frequency or more-frequency antennas suitable for implementation.

[0086] For example, in some alternative embodiments, the above inventive concept can also be used to realize dual-frequency or multi-frequency slot antennas for GPS and Bluetooth multiplexing, GPS and 4G LTE multiplexing, Bluetooth and 4G / 5G multiplexing, 4G and 5G multiplexing. The present disclosure does not limit the type of the antenna.

[0087] In some other alternative embodiments, the structure of the slot antenna of the device of the present disclosure is not limited to that shown in the above embodiments.

[0088] For example, in some examples, the device of the present disclosure includes a main board and a first conductor. The first conductor and the main board are arranged opposite to each other with a gap therebetween, so that the gap therebetween forms a radiation slot. That is Figure 1 as shown in, the first conductor is the conductive metal middle frame 200, and the slot 610 is formed by the distance between the complete device main board 300 and the middle frame 200. And in Figure 11 the shown embodiment, the slot 610 can also be formed by the incomplete device main board 300 and the middle frame 200. In Figure 12 the example embodiment, the shape of the smart watch is not limited to a circle, and can also be any other shape suitable for implementation, such as a rounded rectangle, etc. The present disclosure does not need to limit this. Those skilled in the art can undoubtedly understand and fully implement it based on the foregoing embodiments, and the present disclosure will not elaborate on this anymore.

[0089] For example, in some other examples, the device of the present disclosure includes a second conductor. The second conductor is electrically connected to the grounding unit, and a slot is opened on the second conductor. Specifically, the second conductor can be the all-metal shell of the watch. The all-metal shell means that both the outer middle frame and the bottom shell of the watch are made of conductive metal materials. The metal shell is electrically connected to the grounding unit of the device main board, so that the shell is equivalent to the ground. The radiation slot of the slot antenna is opened on the shell, for example, surrounded and opened on the middle frame of the watch, and the slot antenna structure of the present disclosure can also be realized. The principle of the antenna structure in this example is the same as that of the foregoing. Those skilled in the art can understand and fully implement it with reference to the foregoing and related technologies, and the present disclosure will not elaborate on this anymore.

[0090] As can be seen from the foregoing, the device of the embodiment of the present disclosure adjusts the multi-order resonance frequencies of the slot antenna through the first inductor and the first capacitor, so as to realize a slot antenna including multiple available frequency bands by using the same antenna structure, and realize the design of a multi-frequency slot antenna.

[0091] For the device of the embodiment of the present disclosure, the operating frequencies of the slot antenna include a first resonance and a second resonance. The first resonance is the second-order resonance frequency for realizing the GPS L5 radiation frequency band, and the second resonance is the third-order resonance frequency for realizing the GPS L1 radiation frequency band. The double-frequency GPS antenna is realized by using the resonance frequencies of the second and third-order frequency doubling relationships that are relatively close to the frequency doubling of GPS L1 and L5, which is more conducive to adjusting the antenna resonance frequency and simplifies the design process.

[0092] The device according to the embodiment of the present disclosure further includes a third resonance in its operating frequency. The third resonance is the fourth-order resonance frequency and is used to achieve the radiation frequency band of the Bluetooth / WiFi antenna. The multiple-frequency relationship between the GPS L5 frequency band and the Bluetooth / WiFi frequency band is relatively close to the multiple-frequency relationship between the first resonance and the third resonance. Therefore, by using the third resonance to achieve the Bluetooth / WiFi frequency band, that is, using the same antenna structure to simultaneously implement the dual-frequency GPS and Bluetooth / WiFi antennas, there is no need to additionally set up a Bluetooth / WiFi antenna, which simplifies the internal structure of the device.

[0093] For the device according to the embodiment of the present disclosure, the operating frequency of the slot antenna includes two resonance frequencies. The first capacitor is located at a position where the voltage value of one resonance frequency is zero and the voltage value of the other resonance frequency is not zero. Thus, the first capacitor can independently adjust the other resonance frequency without affecting one resonance frequency. Moreover, under the action of the first capacitor, the independent adjustment of one resonance frequency can be achieved by the inductance value of the first inductor, which is more conducive to the design of the dual-frequency antenna.

[0094] For the device according to the embodiment of the present disclosure, when the device is a mobile terminal, the radiation slot of the slot antenna can be realized by using the main board and the metal middle frame of the terminal, or by using the slot on the metal shell, thus providing more design solutions for the antenna design of the terminal with a metal shell.

[0095] Obviously, the above embodiments are merely examples for clear illustration and are not limitations on the embodiments. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. The obvious changes or variations derived therefrom still fall within the protection scope of the present disclosure.

Claims

1. A device with a slot antenna, characterized in that, Comprising: A radiation slot formed on the device; A feeding terminal, one end of which is connected across the slot to the feeding point of the slot antenna, and the other end of which is electrically connected to the radio frequency unit of the device; A first inductor, one end of which is connected across the slot to the grounding point of the slot antenna, and the other end of which is electrically connected to the grounding unit of the device; And A first capacitor, disposed in the slot and with two electrodes of the first capacitor respectively connected to two ends in the width direction of the slot. In the length direction of the slot, the first capacitor is located between the feeding terminal and the first inductor; The operating frequency of the slot antenna includes a first frequency band and a second frequency band. The first frequency band is realized by the first resonance of the slot antenna, and the second frequency band is realized by the second resonance of the slot antenna. The first capacitor is used to adjust the first frequency band of the first resonance without affecting the second resonance, and the first inductor is used to adjust the second frequency band of the second resonance without affecting the first resonance.

2. The device according to claim 1, wherein The feeding terminal and the first inductor divide the slot into a first part and a second part. The length of the first part is greater than the length of the second part, and the first capacitor is located in the first part.

3. The device according to claim 1, wherein The first resonance is the second-order resonance frequency of the slot antenna, and the second resonance is the third-order resonance frequency of the slot antenna.

4. The device according to claim 1, wherein The first frequency band includes the L5 frequency band of the GPS satellite positioning system, and the second frequency band includes the L1 frequency band of the GPS satellite positioning system.

5. The device according to claim 4, wherein The operating frequency of the slot antenna further includes a third frequency band, which is realized by the third resonance of the slot antenna, and the third frequency band includes the Bluetooth / WiFi operating frequency band.

6. The device according to claim 1, wherein In the length direction of the slot, the first capacitor is located at a position where the voltage value of the second resonance is zero and the voltage value of the first resonance is not zero.

7. The device according to claim 1, wherein The slot antenna is a half-wavelength slot antenna.

8. The device according to any one of claims 1 to 7, characterized in that Further comprising: A main board, including the grounding unit and the radio frequency unit.

9. The device according to any one of claims 1 to 7, characterized in that Further comprising: A first conductor, the first conductor being disposed opposite to the main board of the device at an interval, so that the interval between the first conductor and the main board forms the slot.

10. The device according to any one of claims 1 to 7, characterized in that, Further comprising: A second conductor, the second conductor being electrically connected to the grounding unit, and the slot being formed on the second conductor.

11. The device according to claim 9, characterized in that, The device is a mobile terminal, The mobile terminal includes: A conductive middle frame, the middle frame forming the first conductor, the middle frame being disposed around the outside of the main board at an interval, and the interval between the middle frame and the main board forming the slot.

12. The device according to claim 10, characterized in that, The device is a mobile terminal, The mobile terminal includes: A conductive housing that forms the second conductor, a main board is disposed inside the housing, a grounding module of the main board is electrically connected to the housing, and the gap is opened on the housing.

13. The device according to any one of claims 1 to 7, characterized in that the device is a wrist-worn device.

Images