Communication device

Abstract

The present application provides a communication device. The communication device comprises a metal housing, a ground plane, and a parasitic stub. A gap is defined between the metal housing and the ground plane, and the metal housing comprises a first grounding point, a second grounding point, and a first feed point; a section of the gap between the metal housing and the ground plane that is located between the first grounding point and the second grounding point is a first slot, so that the metal housing and the ground plane form a first slot antenna between the first grounding point and the second grounding point, and the first feed point is configured for feeding the first slot antenna. The parasitic stub extends in an extension direction of the first slot antenna and is coupled to a feed by means of the first slot antenna, the parasitic stub comprises a grounding end and a first open end, and the parasitic stub is disposed to be grounded at the grounding end. In the extension direction, the grounding end is located in a middle portion of the first slot, and the first open end is located at the first grounding point. The parasitic stub generates a parasitic resonance under excitation of the first slot antenna, thereby improving antenna radiator efficiency and bandwidth.

Description

A communication device

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202411895759.0, filed on December 19, 2024, entitled "A Communication Device", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of communication technology, and in particular to a communication device. Background Technology

[0004] As communication devices become increasingly smaller while their functions become more abundant, it is necessary to integrate more functional modules into a smaller space. In particular, communication devices with communication functions often have antennas installed in smaller devices. The antennas require a certain clearance to operate, so the requirements for antenna design in small communication devices are relatively high.

[0005] Taking watches, especially those with metal frames, as an example in communication devices, the metal frame can be reused as an antenna radiator. Since it's often inconvenient to cut and slit the metal frame of watches and other communication devices to form antenna radiators, multiple radiators are formed within the metal frame using grounding to support communication on different frequency bands. However, current antenna configurations are insufficient to meet the needs of these products. Summary of the Invention

[0006] This application provides a communication device that improves the radiator efficiency and bandwidth of an antenna.

[0007] The communication device provided in this application includes a metal casing, a ground plane, and a parasitic stub. A gap exists between the metal casing and the ground plane. The metal casing includes a first ground point, a second ground point, and a first feed point. The first and second ground points are respectively grounded. The gap between the metal casing and the ground plane is a first slot, thereby forming a first slot antenna between the first and second ground points. The first feed point is used to feed the first slot antenna. The parasitic stub extends along the extension direction of the first slot antenna and is fed through coupling with the first slot antenna. The parasitic stub includes a ground end and a first open end, with the ground end being grounded. Along the extension direction, the ground end is located in the middle of the first slot, and the first open end is located at the first ground point. Under the excitation of the first slot antenna, the parasitic stub will generate a parasitic resonance. The frequency of this parasitic resonance is typically low, thereby improving the radiating efficiency and bandwidth of the antenna.

[0008] In one embodiment, the electrical length of the parasitic stub is λ / 4, where λ is the wavelength of the parasitic stub's radiated signal in free space. This facilitates the miniaturization of the antenna system without compromising the appearance of the metal casing, making it suitable for closed metal casings. This approach also allows for the additional coupling and excitation of the parasitic modes at λ / 4, thereby improving the antenna's radiation efficiency and bandwidth.

[0009] There are multiple options for the grounding method of the parasitic branch's grounding terminal. For example, the grounding terminal of the parasitic branch can be connected to the metal shell or to the floor, both of which can achieve grounding of the parasitic branch. The specific grounding scheme of the parasitic branch can be designed according to the actual structure of the product.

[0010] The first open end of the aforementioned parasitic branch can be connected to a capacitor and / or an inductor. This allows the electrical length of the parasitic branch to be altered, causing it to generate the target parasitic resonant frequency.

[0011] In a further technical solution, the first open end of the parasitic stub can be connected to an adjustable capacitor and / or an adjustable inductor. This allows the capacitance or inductance value to be adjusted according to actual needs, thereby adjusting the electrical length of the parasitic stub and enabling reconfigurable parasitic resonant frequency. This, in turn, enables reconfigurable resonant frequency of the antenna system, thus forming a frequency-reconfigurable communication device.

[0012] Similarly, a capacitor and / or inductor can be connected to the grounding terminal of the parasitic stub. The electrical length of the parasitic stub can also be altered to induce a target parasitic resonant frequency.

[0013] In a further technical solution, the grounding terminal of the aforementioned parasitic stub is connected to an adjustable capacitor and / or an adjustable inductor. This allows the capacitance or inductance value to be adjusted according to actual needs, thereby adjusting the electrical length of the parasitic stub and enabling reconfigurable parasitic resonant frequencies. This, in turn, enables reconfigurable resonant frequencies of the antenna system, thus forming a frequency-reconfigurable communication device.

[0014] In one technical solution, the metal shell further includes a third grounding point, a fourth grounding point, and a second feed point. The third grounding point and the fourth grounding point are respectively grounded, and the second feed point is located between the third grounding point and the fourth grounding point. The second feed point is electrically connected to the radio frequency chip, and the gap between the metal shell and the ground between the third grounding point and the fourth grounding point is a second gap, forming a second gap antenna.

[0015] In one specific technical solution, the aforementioned communication device includes a rear shell, which is fixed to a metal shell, and a parasitic branch is disposed on the rear shell. This solution facilitates the placement of the parasitic branch and creates a certain gap between the parasitic branch and the metal shell, thereby simplifying the fabrication of the communication device.

[0016] The parasitic branches mentioned above can be attached to the back shell, or the back shell can be an injection-molded back shell, with the parasitic branches located inside the injection-molded back shell, that is, the parasitic branches are injection-molded inside the back shell.

[0017] There are various options for the structure and morphology of the parasitic branch. For example, the parasitic branch can be at least one of steel sheet, flexible circuit board, copper foil, silver paste, or conductive fiber. Specifically, the appropriate structure of the parasitic branch can be selected based on factors such as the specific structure of the communication terminal, the space available for setting the parasitic branch, and cost requirements.

[0018] The parasitic segments mentioned above have various structures. In one technical solution, the parasitic segment is a strip-shaped structure, with one end of the strip-shaped parasitic segment being a ground end and the other end being a first open end.

[0019] Alternatively, in one technical solution, the parasitic branch further includes a second open end, located at the end of the grounding end opposite to the first open end. In this technical solution, the parasitic branch extends to both sides at the grounding end.

[0020] The extension length of the parasitic branch towards the second opening end can be designed according to actual needs. In one technical solution, the aforementioned second opening end is located at the second grounding point. This solution can further improve the bandwidth of the antenna system.

[0021] Of course, in some embodiments, the second opening end can also be offset from the second grounding point of the first slot antenna. For example, the second opening end may be located on the side of the second grounding point facing the first grounding point, or the second opening end may also be located on the side of the second grounding point away from the first grounding point.

[0022] Similarly, the second open end of the parasitic stub is connected to a capacitor and / or an inductor. The electrical length of the parasitic stub can also be altered to allow it to generate the target parasitic resonant frequency.

[0023] In a further technical solution, the second open end of the parasitic stub is connected to an adjustable capacitor and / or an adjustable inductor. This allows the capacitance or inductance value to be adjusted according to actual needs, thereby adjusting the electrical length of the parasitic stub and enabling reconfigurable parasitic resonant frequency. This, in turn, enables reconfigurable resonant frequency of the antenna system, thus forming a frequency-reconfigurable communication device.

[0024] In one technical solution, the region between the grounding end and the first open end of the parasitic branch is grounded via a capacitor and / or an inductor. Alternatively, the electrical length of the parasitic branch can be altered to generate a target parasitic resonant frequency.

[0025] In a further technical solution, the area between the parasitic stub and the first open end is grounded via an adjustable capacitor and / or an adjustable inductor. This allows the capacitance or inductance value to be adjusted according to actual needs, thereby adjusting the electrical length of the parasitic stub and enabling reconfigurable parasitic resonant frequency. This, in turn, enables reconfigurable resonant frequency of the antenna system, thus forming a frequency-reconfigurable communication device.

[0026] In this application, the communication device may include at least two first slot antennas, each of which is connected to a parasitic stub. Therefore, the communication device may include at least two slot antennas with parasitic stubs, which is beneficial for further improving the bandwidth and efficiency of the communication device. Attached Figure Description

[0027] Figure 1 is a schematic diagram of a communication device in an embodiment of this application;

[0028] Figure 2 is a partial structural schematic diagram of the communication device in an embodiment of this application;

[0029] Figure 3 is an equivalent schematic diagram of the antenna of the communication device in the embodiment of this application;

[0030] Figure 4 is a schematic diagram of an antenna system in an embodiment of this application;

[0031] Figure 5 is a schematic diagram of a return loss of an antenna system in an embodiment of this application;

[0032] Figure 6 is a schematic diagram of the radiation efficiency of an antenna system in an embodiment of this application;

[0033] Figure 7 is a schematic diagram of a return loss of an antenna system in an embodiment of this application;

[0034] Figure 8 is a schematic diagram of the radiation efficiency of an antenna system in an embodiment of this application;

[0035] Figure 9 is a schematic diagram of a return loss of an antenna system in an embodiment of this application;

[0036] Figure 10 is a schematic diagram of the radiation efficiency of an antenna system in an embodiment of this application;

[0037] Figure 11 is a schematic diagram of the antenna system of a communication device in an embodiment of this application;

[0038] Figure 12 is a schematic diagram of two antenna modes generated by the communication device in an embodiment of this application;

[0039] Figure 13 is a schematic diagram of the communication device generating a first mode in an embodiment of this application;

[0040] Figure 14 is a schematic diagram of the communication device generating the second mode in an embodiment of this application;

[0041] Figure 15 is a schematic diagram of the return loss of the antenna system of the communication device in an embodiment of this application;

[0042] Figure 16 is a schematic diagram of the antenna system of a communication device in an embodiment of this application;

[0043] Figure 17 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application;

[0044] Figure 18 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application;

[0045] Figure 19 is a schematic diagram of the antenna system of a communication device in an embodiment of this application;

[0046] Figure 20 is a schematic diagram of the return loss of the antenna system of the communication device in an embodiment of this application;

[0047] Figure 21 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application;

[0048] Figure 22 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application;

[0049] Figure 23 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application;

[0050] Figure 24 is a schematic diagram of the antenna system of a communication device in an embodiment of this application;

[0051] Figure 25 is a schematic diagram of the return loss of the antenna system of the communication equipment in the comparative example of this application;

[0052] Figure 26 is a schematic diagram of the antenna efficiency of an antenna system in a comparative example of this application;

[0053] Figure 27 is a schematic diagram of an antenna system of a communication device in the comparative example of this application;

[0054] Figure 28 is a schematic diagram of an antenna system of a communication device in the comparative example of this application;

[0055] Figure 29 is a schematic diagram of the return loss of an antenna system in a comparative example of this application;

[0056] Figure 30 is a schematic diagram of the antenna efficiency of an antenna system in a comparative example of this application;

[0057] Figure 31 is a partial structural diagram of a communication device in an embodiment of this application;

[0058] Figure 32 is a schematic diagram of a working frequency band of a communication device in an embodiment of this application;

[0059] Figure 33 is a schematic diagram of the return loss curve of the first slot antenna of the communication device in the embodiment of this application;

[0060] Figure 34 is a schematic diagram of the antenna efficiency of the first slot antenna of the communication device in an embodiment of this application;

[0061] Figure 35 is a schematic diagram of the isolation curve of the dual antennas of the communication device in the embodiment of this application;

[0062] Figure 36 is a schematic diagram of the return loss curve of the second slot antenna of the communication device in the embodiment of this application;

[0063] Figure 37 is a schematic diagram of the antenna efficiency of the second slot antenna in the embodiment of this application;

[0064] Figure 38 is a model diagram of a communication device in a hand mold state according to an embodiment of this application;

[0065] Figure 39 is a schematic diagram of a return loss curve of an antenna system in an embodiment of this application;

[0066] Figure 40 is a schematic diagram of the antenna efficiency of the antenna system in an embodiment of this application;

[0067] Figure 41 is a schematic diagram of the S21 curve of the dual antennas in the hand-shaped state in the embodiment of this application;

[0068] Figure 42 is a cross-sectional structural diagram of a communication device in an embodiment of this application;

[0069] Figure 43 is a front view of the communication device in an embodiment of this application;

[0070] Figure 44 is a schematic diagram of the rear structure of the communication device in an embodiment of this application;

[0071] Figure 45 is a partial structural diagram of a communication device in an embodiment of this application;

[0072] Figure 46 is a schematic diagram of the radiation efficiency of the antenna system of the communication device in an embodiment of this application;

[0073] Figure 47 is a schematic diagram of a communication device in an embodiment of this application;

[0074] Figure 48 is a partial structural diagram of a communication device in an embodiment of this application;

[0075] Figure 49 is a schematic diagram of the antenna efficiency of the communication device in the hand-shaped state in an embodiment of this application;

[0076] Figure 50 is a schematic diagram of a communication device in an embodiment of this application;

[0077] Figure 51 is a schematic diagram of a communication device in an embodiment of this application;

[0078] Figure 52 is a schematic diagram of a communication device in an embodiment of this application;

[0079] Figure 53 is a schematic diagram of the antenna system of a communication device in an embodiment of this application;

[0080] Figure 54 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application;

[0081] Figure 55 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application.

[0082] Reference numerals: 1-Metal casing; 11-First grounding point; 12-Second grounding point; 13-First feed point; 14-First slot; 15-First slot antenna; 16-Third grounding point; 17-Fourth grounding point; 18-Second feed point; 19-Second slot; 110-Second slot antenna; 111-Fifth grounding point; 2-Ground; 3-Parasitic branch; 31-Grounding end; 32-First opening end; 33-Capacitor / Inductor; 34-Second opening end; 4-Hand mold; 5-Rear shell; 6-Spring piece; 7-Adapter piece. Detailed Implementation

[0083] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0084] The terminology used in the following embodiments is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise.

[0085] References to “an embodiment” or “a specific embodiment” as used in this specification mean that one or more embodiments of this application include a particular feature, structure, or characteristic described in connection with that embodiment. The terms “comprising,” “including,” “having,” and variations thereof mean “including, but not limited to,” unless otherwise specifically emphasized.

[0086] To facilitate understanding of the communication device provided in the embodiments of this application, its application scenarios will be introduced first below.

[0087] Communication devices require antennas to communicate during operation. To accommodate the miniaturization of communication devices, existing metal structures such as the device's casing can be used as antenna radiators. For example, when the communication device is a mobile terminal such as a mobile phone or tablet, a metal frame can be used as the antenna radiator; when the communication device is a wearable terminal such as a smartwatch or sports watch, a metal watch bezel can be used as the antenna radiator.

[0088] The communication devices in this application embodiment can be mobile phones, tablets, laptops, smart home products, smart bracelets, smartwatches, smart helmets, smart glasses, vehicle smart navigation devices, security smart sensing devices, drones, unmanned transport vehicles, robots, or medical sensing products, etc. Communication devices can also be handheld devices with wireless communication capabilities, computing devices or other processing devices connected to a wireless modem, in-vehicle devices, or electronic devices in future evolved public land mobile networks (PLMNs), etc., and this application embodiment is not limited to these categories.

[0089] Any of the aforementioned communication devices may include the antenna system described in this application embodiment to realize the communication or detection functions of the communication device. In specific embodiments, the antenna system in the aforementioned communication device can be directly installed on the electronic device and electrically connected to the processor in the communication device to realize the communication and / or detection functions of the communication device. Alternatively, the antenna system can be integrated into a sensor or sensing module, and then the sensor or sensing module can be installed on the communication device, with the processor of the communication device electrically connected to the sensor or sensing module to realize the communication and / or detection functions of the communication device. The aforementioned processor may specifically refer to a chip, as long as it can process data and realize at least some of the functions of the electronic device; this application does not impose any limitations on this.

[0090] To facilitate understanding of the embodiments of this application, the terminology appearing in the embodiments of this application will be briefly introduced below.

[0091] Capacitor: can be understood as lumped capacitance and / or distributed capacitance. Lumped capacitance refers to capacitive components, such as capacitor elements; distributed capacitance (or distributed capacitance) refers to the equivalent capacitance formed by two conductive components separated by a certain gap.

[0092] Inductance: can be understood as lumped inductance and / or distributed inductance. Lumped inductance refers to inductive components, such as inductor elements; distributed inductance (or distributed inductance) refers to the equivalent inductance formed through a conductive element of a certain length.

[0093] Resonant frequency: The resonant frequency is also called the resonance frequency. The resonant frequency can have a frequency range, that is, the frequency range in which resonance occurs. The resonant frequency can be a frequency range where the return loss characteristic is less than -6dB. The frequency corresponding to the strongest resonance is the center frequency – the point frequency. The return loss characteristic at the center frequency can be less than -20dB.

[0094] Communication / Operating Frequency Band: Regardless of the type of antenna, it always operates within a certain frequency range (bandwidth). For example, an antenna supporting the B40 band operates within the frequency range of 2300MHz to 2400MHz, or in other words, its operating frequency band includes the B40 band. The frequency range that meets the specifications can be considered the antenna's operating frequency band. The width of the operating frequency band is called the operating bandwidth. The operating bandwidth of an omnidirectional antenna may reach 3-5% of the center frequency. The operating bandwidth of a directional antenna may reach 5-10% of the center frequency. Bandwidth can be considered as a frequency range on both sides of the center frequency (e.g., the resonant frequency of a dipole), where the antenna characteristics are within the acceptable range of the center frequency.

[0095] The resonant frequency band and the operating frequency band can be the same or different, or their frequency ranges can partially overlap. In one embodiment, the resonant frequency band of the antenna can cover multiple operating frequency bands of the antenna.

[0096] Ground / Plane: This can broadly refer to at least a portion of any grounding layer, ground plane, or grounding metal layer within an electronic device (such as a mobile phone), or at least a portion of any combination of the aforementioned grounding layers, ground planes, or grounding components. "Ground" can be used for grounding components within an electronic device. In one embodiment, "ground" may include any one or more of the following: a grounding layer of a circuit board of an electronic device, a ground plane formed by the frame of the electronic device, a grounding metal layer formed by a thin metal film beneath the screen, a conductive grounding layer of a battery, and conductive components or metal parts electrically connected to the aforementioned grounding layer / ground plane / metal layer. In one embodiment, the circuit board may be a printed circuit board (PCB), such as an 8-layer, 10-layer, or 12-14-layer board having 8, 10, 12, 13, or 14 layers of conductive material, or components separated and electrically insulated by dielectric or insulating layers such as glass fiber or polymers.

[0097] Any of the aforementioned grounding layers, ground planes, or grounding metal layers are made of conductive materials. In one embodiment, the conductive material may be any of the following: copper, aluminum, stainless steel, brass and their alloys, copper foil on an insulating substrate, aluminum foil on an insulating substrate, gold foil on an insulating substrate, silver-plated copper, silver-plated copper foil on an insulating substrate, silver foil on an insulating substrate and tin-plated copper, graphite-impregnated cloth, graphite-coated substrates, copper-plated substrates, brass-plated substrates, and aluminum-plated substrates. Those skilled in the art will understand that grounding layers / ground planes / grounding metal layers may also be made of other conductive materials.

[0098] Grounding: refers to coupling with the aforementioned ground / floor in any way. In one embodiment, grounding can be achieved through physical grounding, such as through a structural component of the mid-frame to achieve a physical ground at a specific location on the frame (or, physical ground). In another embodiment, grounding can be achieved through device grounding, such as through devices like capacitors / inductors / resistors connected in series or parallel (or, device ground).

[0099] End / Point: The term "end / point" in the context of the antenna radiator's first end / second end / feed end / ground end / feed point / ground point / connection point should not be narrowly interpreted as necessarily a single point. It can also be considered as a segment of the antenna radiator including its first endpoint; nor should it be narrowly interpreted as necessarily an endpoint or end disconnected from other radiators. It can also be considered as a point or segment on a continuous radiator. In one embodiment, "end / point" can include the endpoint of the antenna radiator at the first gap. For example, the first end of the antenna radiator can be considered as a segment of the radiator within 5 mm (e.g., 2 mm) of the gap. In another embodiment, "end / point" can include a connection / coupling region on the antenna radiator that couples to other conductive structures. For example, a feed end / feed point can be a coupling region on the antenna radiator that couples to a feed structure or feed circuit (e.g., a region facing a part of the feed circuit). Similarly, a ground end / ground point can be a connection / coupling region on the antenna radiator that couples to a ground structure or ground circuit.

[0100] Open terminal, closed terminal: In some embodiments, open terminal / closed terminal refers to whether or not it is grounded; the closed terminal is grounded, and the open terminal is not grounded. In some embodiments, open terminal / closed terminal refers to other conductors; the closed terminal is electrically connected to other conductors, and the open terminal is not electrically connected to other conductors. In one embodiment, the open terminal may also be referred to as an open end or an open circuit terminal. In one embodiment, the closed terminal may also be referred to as a ground terminal or a short circuit terminal.

[0101] The current unidirectional / reverse distribution mentioned in the embodiments of this application should be understood as the main currents on conductors on the same side being in the same / reverse direction. For example, when a unidirectional current is excited on a bent or looped conductor (e.g., the current path is also bent or looped), it should be understood that, for example, the main currents excited on the conductors on both sides of a looped conductor (e.g., on the conductors on both sides of a gap) are in opposite directions, but still fall under the definition of unidirectional current in this application. In one embodiment, unidirectional current on a conductor can mean that the current on that conductor has no reversal point. In one embodiment, reversible current on a conductor can mean that the current on that conductor has at least one reversal point. In one embodiment, unidirectional current on two conductors can mean that the currents on both conductors have no reversal points and flow in the same direction. In one embodiment, reversible current on two conductors can mean that the currents on both conductors have no reversal points and flow in opposite directions. The unidirectional / reverse current on multiple conductors can be understood accordingly.

[0102] Antenna efficiency: refers to the ratio of the power radiated into space by the antenna (i.e. the power that is effectively converted into electromagnetic waves) to the input power of the antenna.

[0103] Those skilled in the art will understand that efficiency is generally expressed as a percentage, and there is a corresponding conversion relationship between it and dB. The closer the efficiency is to 0dB, the better the efficiency of the antenna.

[0104] dB: This stands for decibel, a logarithmic concept with base 10. Decibels are used to evaluate the proportional relationship between two physical quantities; they themselves have no physical dimensions. For every 10-fold increase in the ratio between two quantities, their difference can be expressed as 10 decibels. For example: A = 100, B = 10, C = 5, D = 1, then A / D = 20 dB; B / D = 10 dB; C / D = 7 dB; B / C = 3 dB. In other words, a 10-decibel difference between two quantities is a 10-fold difference, a 20-decibel difference is a 100-fold difference, and so on. A 3-decibel difference is a 2-fold difference between the two quantities.

[0105] Antenna return loss: This can be understood as the ratio of the signal power reflected back to the antenna port after passing through the antenna circuit to the transmit power at the antenna port. The smaller the reflected signal, the larger the signal radiated into space through the antenna, and the higher the antenna's radiation efficiency. Conversely, the larger the reflected signal, the smaller the signal radiated into space through the antenna, and the lower the antenna's radiation efficiency.

[0106] Antenna return loss can be represented by the S11 parameter, which is one of the S-parameters. S11 represents the reflection coefficient, and this parameter characterizes the antenna's transmission efficiency.

[0107] In one embodiment, the S11 diagram (return loss diagram) can be understood as a schematic diagram representing the resonance generated by the antenna. In one embodiment, the portion of the resonance shown in the S11 diagram that is less than -6dB can be understood as the resonant frequency / frequency range / operating frequency band generated by the antenna. The S11 parameter is usually negative. The smaller the S11 parameter, the smaller the antenna return loss, the less energy reflected back by the antenna itself, which means more energy actually enters the antenna, and the higher the system efficiency of the antenna; the larger the S11 parameter, the greater the antenna return loss, and the lower the system efficiency of the antenna.

[0108] It should be noted that in engineering, an S11 value of -6dB is generally used as the standard. When the S11 value of an antenna is less than -6dB, the antenna can be considered to be working normally, or the antenna can be considered to have good transmission efficiency.

[0109] Specifically, slots can be created within openings in the metal structure to form open-slot antennas, or closed-slot antennas can be formed without openings in the metal structure. Improving the radiation performance of closed-slot antennas is more challenging compared to open-slot antennas. However, with the increasing variety of communication equipment applications, these devices need to support multi-band communication, and open-slot antennas struggle to maintain natural resonance, especially for lower frequency bands.

[0110] Figure 1 is a structural schematic diagram of a communication device in an embodiment of this application; Figure 2 is a partial structural schematic diagram of the communication device in an embodiment of this application; and Figure 3 is an equivalent schematic diagram of the antenna of the communication device in an embodiment of this application. As shown in Figures 1 to 3, in one embodiment, the communication device includes a metal shell 1, a ground plane 2, and parasitic stubs 3. The metal shell 1, ground plane 2, and parasitic stubs 3 form the antenna system of the communication device. There is a gap between the metal shell 1 and the ground plane 2, which facilitates the metal shell 1 to become a slot antenna. Specifically, the metal shell 1 includes a first grounding point 11, a second grounding point 12, and a first feed point 13. The first grounding point 11 and the second grounding point 12 are respectively grounded. Specifically, the first grounding point 11 and the second grounding point 12 can be connected to the ground plane 2 to achieve grounding. The gap between the metal shell 1 and the ground plane 2 is a first slot 14, forming a first slot antenna 15. The first feed point 13 is used to feed the first slot antenna 15. The parasitic stub 3 extends along the extension direction of the first slot antenna 15 and is fed through the first slot antenna 15. The parasitic stub 3 includes a grounding end 31 and a first opening end 32. Along the extension direction, the grounding end 31 is located in the middle of the first slot 14. Typically, the first slot antenna 15 has a large electric field point in the middle of the first slot 14; therefore, the parasitic stub 3 is grounded at the large electric field point. The first opening end 32 is located at the first grounding point 11. The first slot antenna 15 has a small electric field point at the grounding end 31; therefore, the parasitic stub 3 is open at the small electric field point. It is understood that the electric field strength at the large electric field point is greater than the electric field strength at the small electric field point. In some embodiments, the large electric field point may also be the region with the largest electric field in the first slot 14, and the small electric field point may also be the region with the smallest electric field in the first slot 14.

[0111] In this embodiment, the parasitic stub 3 will generate parasitic resonance under the excitation of the first slot antenna 15. The frequency of the parasitic resonance is usually low, thereby improving the radiating efficiency and bandwidth of the antenna.

[0112] When the aforementioned communication device is a mobile phone or tablet, the aforementioned metal shell 1 can be a mid-frame; when the aforementioned communication device is a watch or bracelet, the aforementioned metal shell 1 can be a watch bezel.

[0113] Specifically, the middle part of the first gap 14 refers to approximately the middle part of the first gap 14. For example, the distance between the grounding end 31 of the parasitic branch 3 and the first grounding point 11 is equal to the distance between the grounding end 31 of the parasitic branch 3 and the second grounding point 12, or the distance between the grounding end 31 of the parasitic branch 3 and the first grounding point 11 and the distance between the grounding end 31 of the parasitic branch 3 and the second grounding point 12 differs by no more than 10%.

[0114] In one embodiment, the first open end 32 of the parasitic stub 3 is aligned with the first grounding point 11 of the first slot antenna 15, and the other end extends from the first grounding point 11 toward the second grounding point 12. In the direction from the first grounding point 11 toward the second grounding point 12, which is also the extension direction of the first slot antenna 15, the parasitic stub 3 is located in the interval where the first slot antenna 15 is located, thereby facilitating the use of the first slot antenna 15 to power the parasitic stub 3.

[0115] In this embodiment, the electrical length of the parasitic stub 3 is λ / 4, where λ is the wavelength of the radiated signal from the parasitic stub 3 in free space. By increasing the parasitic stub 3 by λ / 4, a lower resonant frequency can be generated, and the resonant frequency of the first slot antenna 15 can be increased. This facilitates the miniaturization of the antenna system without compromising the appearance of the metal shell 1, making it suitable for closed metal shells. This scheme also facilitates the additional coupling and excitation of the parasitic modes by λ / 4, thereby improving the antenna's radiation efficiency and bandwidth.

[0116] To analyze the effects of the embodiments of this application, the inventors conducted extensive simulation analyses. For example, in the analysis of the planar slot antenna. Figure 4 is a schematic diagram of an antenna system in an embodiment of this application. As shown in Figure 4, a first slot 14 is formed between the metal shell 1 and the ground plane 2, forming a first slot antenna 15. The two ends of the first slot antenna 15 are a first ground point 11 and a second ground point 12, respectively. Feeding is performed between the first ground point 11 and the second ground point 12, specifically using an offset feeding scheme to feed the first slot antenna 15. In a specific embodiment, the first feed point 13 is electrically connected to the RF chip and is used to feed the metal shell 1. The first feed point 13 is located between the first ground point 11 and the second ground point 12. The distance between the first feed point 13 and the first ground point 11 is different from the distance between the first feed point 13 and the second ground point 12. The parasitic branch 3 extends along the first slot 14, and one end A of the parasitic branch 3 is aligned with the first ground point 11, and the other end B is aligned with the middle of the first slot 14. The first slot antenna 15 and the parasitic stub 3 are considered as a single first antenna.

[0117] Figure 5 is a schematic diagram of the return loss of the antenna system in an embodiment of this application, and Figure 6 is a schematic diagram of the radiation efficiency of the antenna system in an embodiment of this application. The thick line in the figures represents the curve of the antenna system without the parasitic stub 3, where both end A and end B are the first opening end 32. The thin line represents the curve of the antenna system with the parasitic stub 3, where end A is the first opening end 32 and end B is the ground end 31. As shown in Figures 5 and 6, the addition of the parasitic stub 3 generates an additional resonance, and the resonant frequency generated by the parasitic stub 3 is lower than the resonant frequency generated by the first slot antenna 15. Due to the influence of the reverse current of the parasitic stub 3, the resonant frequency of the antenna system shifts towards a higher frequency relative to the first slot antenna 15 without the parasitic stub 3 (here, we focus on the resonance around 1.5 GHz). The parasitic stub 3 improves the low-frequency radiation efficiency of the antenna system; compared to not having the parasitic stub 3, both radiation efficiency and system efficiency are improved.

[0118] Figure 7 is a schematic diagram of the return loss of an antenna system in an embodiment of this application, and Figure 8 is a schematic diagram of the radiation efficiency of a planar slot antenna in an embodiment of this application. The thick lines in the figures represent the curves of the antenna system without the parasitic stub 3, where both end A and end B are the first opening end 32. The thin lines represent the curves of the antenna system with the parasitic stub 3, where end A is the ground end 31 and end B is the first opening end 32. As shown in Figures 7 and 8, the parasitic stub 3 and the first slot antenna 15 are weakly coupled, making it difficult to excite new resonances and having little impact on antenna efficiency. The parasitic stub 3 has little effect on the first slot antenna 15.

[0119] Figure 9 is a schematic diagram of the return loss of an antenna system in an embodiment of this application, and Figure 10 is a schematic diagram of the radiation efficiency of an antenna system in an embodiment of this application. The curves in the figures represent the antenna system without the parasitic stub 3, where both end A and end B are first opening ends 32. The thin lines in the figures represent the antenna system with the parasitic stub 3, where both end A and end B are ground ends 31. As shown in Figures 9 and 10, the parasitic stub 3 effectively extends the radiator of the first slot antenna 15, making it difficult to excite new radiators. While it can improve antenna efficiency at lower frequencies (e.g., 1.5 GHz as shown in the figures), it reduces antenna efficiency at higher frequencies (e.g., 3.2 GHz as shown in the figures).

[0120] The characteristics of the ring-shaped slot antenna are basically the same as those of the planar slot antenna described above, and will not be repeated here. In summary, slot antennas formed by the metal shell 1 in various shapes can adopt the technical solution of this application.

[0121] Figure 11 is a structural schematic diagram of the antenna system of the communication device in an embodiment of this application, and Figure 12 is a schematic diagram of two antenna modes generated by the communication device in an embodiment of this application. As shown in Figures 11 and 12, the communication device in this embodiment generates two antenna modes, namely the first mode and the second mode.

[0122] Figure 13 is a schematic diagram of the communication device generating a first mode in an embodiment of this application. As shown in Figure 13, the first mode of the two modes generated by the communication device is a slot antenna mode, consisting of a first slot antenna 15 composed of a metal shell 1 and a ground plane 2. Figure 14 is a schematic diagram of the communication device generating a second mode in an embodiment of this application. As shown in Figure 14, the second mode of the two antenna modes is a wire antenna mode generated by the interaction of currents generated by the metal shell 1 and the parasitic stub 3. After the metal shell 1 is fed, the current flows through the metal shell 1 to the opposite side, then returns through the grounding of the metal shell 1 and the ground plane 2, and then connects to the parasitic stub 3 through the grounding terminal 31. The current flows on the parasitic stub 3 to the end and couples with the feed, forming a new mode. The left side view (front view of the communication device) of Figure 14 shows the current generated by the metal shell 1, and the right side view (rear view of the communication device) shows the current generated by the parasitic stub 3.

[0123] Figure 15 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application. As shown in Figure 15, in a specific technical solution, the antenna system of the communication device generates two resonances at low frequencies, with the resonant centers of the two resonances at 0.735 GHz and 0.894 GHz, respectively. Therefore, this solution can generate a lower resonant frequency, improving the radiation efficiency and bandwidth of the antenna.

[0124] Figure 16 is a schematic diagram of an antenna system of a communication device according to an embodiment of this application. As shown in Figure 16, in one embodiment, the ground terminal 31 of the parasitic stub 3 is connected to a capacitor 33 or an inductor 33; or, in another embodiment, the ground terminal 31 of the parasitic stub 3 is connected to both a capacitor 33 and an inductor 33. This adjusts the electrical length of the parasitic stub 3, causing it to generate a target parasitic resonant frequency. For example, connecting a capacitor 33 to the ground terminal 31 of the parasitic stub 3 can shift the high-frequency resonant frequency, generating a higher parasitic resonant frequency; connecting an inductor 33 to the ground terminal 31 of the parasitic stub 3 can shift the low-frequency resonant frequency, generating a lower parasitic resonant frequency.

[0125] In one embodiment, the ground terminal 31 of the parasitic stub 3 can be connected to an adjustable capacitor 33 or an adjustable inductor 33. Alternatively, in another embodiment, the ground terminal 31 of the parasitic stub 3 is connected to an adjustable capacitor 33 or an adjustable inductor 33. By adjusting the capacitance of the adjustable capacitor 33 or the inductance of the adjustable inductor 33, the parasitic resonant frequency can be reconfigured, thereby enabling the resonant frequency of the antenna system to be reconfigured, thus forming a frequency-reconfigurable communication device.

[0126] In specific embodiments, the grounding method of the parasitic branch 3 can be selected in several ways. For example, the parasitic branch 3 can be connected to the metal shell 1 to achieve grounding. Alternatively, the parasitic branch can be connected to the floor to achieve grounding. When the grounding terminal 31 of the parasitic branch 3 is connected to the floor 2, the aforementioned structures such as the capacitor 33, inductor 33, adjustable capacitor 33, and adjustable inductor 33 can be fabricated on the floor 2, which helps to simplify the fabrication process and technology of the parasitic branch 3.

[0127] Figure 17 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application, and Figure 18 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application. Taking an adjustable inductor 33 connected to ground terminal 31 as an example, the curves of return loss and antenna efficiency of the antenna system formed by adjusting the inductance value of the adjustable inductor 33 are shown in Figures 17 and 18. The thinnest line in the figures represents the curve corresponding to the parasitic stub 3 connected to the 0nH inductor 33, the middle-thick lines represent the curve corresponding to the parasitic stub 3 connected to the 1nH inductor 33, and the thickest line represents the curve corresponding to the parasitic stub 3 connected to the 2nH inductor 33. By adjusting the inductance value of the adjustable inductor 33 connected to ground terminal 31 of the parasitic stub 3, the low-frequency resonant frequency of the antenna system is shifted, and the resonant frequency of the antenna system can be reconstructed. In addition, the antenna efficiency of the antenna system can be improved.

[0128] Figure 19 is a schematic diagram of an antenna system of a communication device according to an embodiment of this application. As shown in Figure 19, in one embodiment, the first open end 32 of the parasitic branch 3 is connected to a capacitor 33 or an inductor 33; or, in another embodiment, the first open end 32 of the parasitic branch 3 is connected to both a capacitor 33 and an inductor 33. This allows the electrical length of the parasitic branch 3 to be changed, enabling the parasitic branch 3 to generate a target parasitic resonant frequency. For example, connecting a capacitor 33 to the first open end 32 of the parasitic branch 3 can shift the low-frequency resonant frequency, generating a lower parasitic resonant frequency; connecting an inductor 33 to the first open end 32 of the parasitic branch 3 can shift the high-frequency resonant frequency, generating a higher parasitic resonant frequency.

[0129] In one embodiment, the first open end 32 of the parasitic branch 3 can be connected to an adjustable capacitor 33 or an adjustable inductor 33; alternatively, in another embodiment, the first open end 32 of the parasitic branch 3 is connected to an adjustable capacitor 33 or an adjustable inductor 33. By adjusting the capacitance of the adjustable capacitor 33 or the inductance of the adjustable inductor 33, the parasitic resonant frequency can be reconfigured, thereby enabling the resonant frequency of the antenna system to be reconfigured, thus forming a frequency-reconfigurable communication device.

[0130] Figure 20 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application, and Figure 21 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application. Taking the first opening end 32 connected to an adjustable inductor 33 as an example, the return loss and antenna efficiency curves of the antenna system formed by adjusting the inductance value of the adjustable inductor 33 are shown in Figures 20 and 21. In the figures, the dashed lines represent the curves corresponding to the parasitic stub 3 connected to the 10nH inductor 33, the broken lines represent the curves corresponding to the parasitic stub 3 connected to the 15nH inductor 33, the solid lines represent the curves corresponding to the parasitic stub 3 connected to the 20nH inductor 33, and the dotted lines represent the curves corresponding to the parasitic stub 3 connected to the 30nH inductor 33. By adjusting the inductance value of the adjustable inductor 33 connected to the first opening end 32 of the parasitic stub 3, the high-frequency resonant frequency of the antenna system is shifted, and the resonant frequency of the antenna system can be reconstructed. In addition, the antenna efficiency of the antenna system can be improved.

[0131] Figure 22 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application, and Figure 23 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application. Taking an adjustable capacitor 33 connected to the first opening end 32 as an example, the curves of return loss and antenna efficiency of the antenna system formed by adjusting the capacitance value of the adjustable capacitor 33 are shown in Figures 22 and 23. In the figures, the dashed lines represent the curves corresponding to the absence of parasitic stubs 3, the dotted lines represent the curves corresponding to the connection of the parasitic stub 3 to a 0pF capacitor 33, and the solid lines represent the curves corresponding to the connection of the parasitic stub 3 to a 0.3pF capacitor 33. By adjusting the capacitance value of the adjustable capacitor 33 connected to the first opening end 32 of the parasitic stub 3, the low-frequency resonant frequency of the antenna system is shifted, and the resonant frequency of the antenna system can be reconstructed. In addition, the antenna efficiency of the antenna system can be increased.

[0132] To verify the effectiveness of the embodiments of this application, several comparative examples are also provided. Figure 24 is a structural schematic diagram of the antenna system of the communication device in an embodiment of this application. As shown in Figure 24, in one comparative example, the first opening end 32 of the parasitic branch 3 is located in the middle of the first gap 14, and the grounding end 31 is located at the first grounding point 11. Figure 25 is a schematic diagram of the return loss of the antenna system of the communication device in the comparative example of this application, and Figure 26 is a schematic diagram of the antenna efficiency of the antenna system of the communication device in the comparative example of this application. As shown in Figures 25 and 26, although resonance will occur, the resonance is very shallow, and the effect on improving the bandwidth and efficiency of the antenna is not obvious.

[0133] Figure 27 is a schematic diagram of the antenna system of a communication device in a comparative example of this application, and Figure 28 is a schematic diagram of the antenna system of a communication device in a comparative example of this application. As shown in Figures 27 and 28, in one comparative example, the parasitic stub 3 does not overlap with the first slot antenna 15, or in other words, the parasitic stub 3 is located in an area outside the extending direction of the first slot antenna 15. In the comparative example shown in Figure 27, the grounding end 31 of the parasitic stub 3 is located close to the first slot antenna 15. Specifically, the grounding end 31 is located at the first grounding point 11 of the first slot antenna 15, and the first opening end 32 is located at the end of the grounding end 31 away from the first slot antenna 15. In the comparative example shown in Figure 28, the grounding end 31 of the parasitic stub 3 is away from the first slot antenna 15. Specifically, the first opening end 32 of the parasitic stub 3 is located at the first grounding end 31 of the first slot antenna 15, and the grounding end 31 is located at the end of the first opening end 32 away from the first slot antenna 15. Figure 29 is a schematic diagram of the return loss of the antenna system of the communication equipment in the comparative example of this application, and Figure 30 is a schematic diagram of the antenna efficiency of the antenna system of the communication equipment in the comparative example of this application. As shown in Figures 29 and 30, although resonance will also occur, the resonance is very shallow, the parasitic resonance frequency is too high, and an efficiency dip will occur.

[0134] Figure 31 is a partial structural diagram of a communication device in an embodiment of this application. As shown in Figure 31, in one embodiment, the metal shell 1 further includes a third grounding point 16, a fourth grounding point 17, and a second feed point 18. The third grounding point 16 and the fourth grounding point 17 are respectively grounded. The gap between the metal shell 1 and the ground plane 2 between the third grounding point 16 and the fourth grounding point 17 is a second slot 19. The second feed point 18 is located between the third grounding point 16 and the fourth grounding point 17 and is electrically connected to the radio frequency chip to feed the second slot 19, thereby forming a second slot antenna 110. In the technical solution of this application, the communication device may include a first slot antenna 15, and may also include a first slot antenna 15 and a second slot antenna 110, which can be designed according to actual needs. The technical solution of this application can increase the communication frequency bands that the communication device can achieve, thereby enriching the communication functions of the communication device.

[0135] In the embodiment shown in Figure 31, the second grounding point 12 and the third grounding point 16 of the metal casing 1 of the communication device are the same grounding point, that is, a single grounding point is shared by the second grounding point 12 and the third grounding point 16. In other embodiments, the second grounding point 12 and the third grounding point 16 may be different grounding points, and this application does not impose any restrictions on this.

[0136] In implementing this technical solution, the length of the first slot 14 can be different from the length of the second slot 19. For example, when the metal casing 1 of the communication device is a circular metal ring, the first slot 14 and the second slot 19 can be two arc-shaped slots with different lengths. This allows the first slot antenna 15 and the second slot antenna 110 to operate in different frequency bands. Specifically, the length of the first slot 14 can be greater than the length of the second slot 19, or the length of the first slot 14 can be less than the length of the second slot 19.

[0137] Figure 32 is a schematic diagram of the operating frequency band of the communication device in an embodiment of this application. As shown in Figure 32, taking the example that the length of the first slot 14 is less than the length of the second slot, the first antenna formed by the first slot antenna and the parasitic branch 3 supports communication in the operating frequency band of Global Navigation Satellite System (GNSS) L5 (1164MHz-1210MHz), the operating frequency band of Bluetooth (BT) (2.4GHz-2.485GHz), and the operating frequency band of Wireless Fidelity (WiFi) (2.400GHz-2.4835GHz). Specifically, the first slot 14 of the first slot antenna 15 is used to realize communication in the operating frequency bands of BT and WiFi, while the setting of the parasitic branch 3 is used to realize communication in the operating frequency band of GNSS L5. The second slot antenna 110 supports communication in the operating frequency band of cellular and the operating frequency band of GNSS L1 (1559MHz-1610MHz). The operating frequency bands of the cell include the low-frequency (LB) band (703MHz~960MHz) and the mid-to-high-frequency (MHB) band (1710MHz~2690MHz).

[0138] Figure 33 is a schematic diagram of the return loss curve of the first slot antenna 15 of the communication device in this embodiment of the present application; Figure 34 is a schematic diagram of the antenna efficiency of the first slot antenna 15 of the communication device in this embodiment of the present application; Figure 35 is a schematic diagram of the isolation curve of the dual antennas of the communication device in this embodiment of the present application; Figure 36 is a schematic diagram of the return loss curve of the second slot antenna 110 of the communication device in this embodiment of the present application; and Figure 37 is a schematic diagram of the antenna efficiency of the second slot antenna 110 in this embodiment of the present application. As shown in Figures 33 to 37, after adding the parasitic stub 3 to the first slot antenna 15, the first slot antenna 15 generates GNSS L5 resonance, and the BT / WiFi band is slightly biased towards a higher frequency. In addition, this scheme also improves the radiation efficiency of the GNSS L5 band of the first slot antenna 15, and the system efficiency of the entire antenna system is also improved. Adding the parasitic stub 3 to the first slot antenna 15 has virtually no impact on the second slot antenna 110.

[0139] This application also simulates the impact of the hand mold 4 on the antenna performance of the communication equipment. Figure 38 is a model diagram of the communication equipment in the hand mold 4 state in an embodiment of this application. The hand mold 4 is set on the side of the parasitic branch 3 away from the first slot 14, and the distance between the hand mold 4 and the parasitic branch 3 is 4mm. Figure 39 is a schematic diagram of the return loss curve of the antenna system in an embodiment of this application. Figure 40 is a schematic diagram of the antenna efficiency of the antenna system in an embodiment of this application. Figure 41 is a schematic diagram of the S21 curve of the dual antennas in the hand mold 4 state in an embodiment of this application. As shown in Figures 39 to 41, in the hand-touching state, the return loss curve of the first slot antenna 15 changes, and the frequency deviation is smaller. The efficiency of the first slot antenna 15 is slightly reduced, but it can still meet the communication requirements.

[0140] Regarding the formation method of the parasitic branch 3 in the embodiments of this application, this application has multiple options. Figure 42 is a cross-sectional structural schematic diagram of a communication device in an embodiment of this application. As shown in Figure 42, in one embodiment, the communication device includes a rear shell 5, which is fixed to a metal shell 1, and the parasitic branch 3 is disposed on the rear shell 5. This results in a certain gap between the parasitic branch 3 and the metal shell 1.

[0141] The specific form of the parasitic branch 3 can be varied. For example, Figure 43 is a schematic diagram of the front structure of the communication device in this embodiment, Figure 44 is a schematic diagram of the back structure of the communication device in this embodiment, and Figure 45 is a schematic diagram of a partial structure of the communication device in this embodiment. In this embodiment, the first feed point 13 is not located between the first ground point 11 and the second ground point 12, but it can still feed the first slot antenna 15. As shown in Figures 43 and 44, the parasitic branch 3 can be at least one of steel sheet, flexible circuit board, copper foil, silver paste, or conductive fiber. The design can be tailored to specific needs. In the embodiment shown in Figure 44, the parasitic branch 3 is a copper foil, which can be attached to the surface of the rear shell 5. In the embodiment shown in Figure 45, the parasitic branch 3 is a steel sheet.

[0142] In another embodiment, the rear shell 5 of the communication device can be an injection-molded rear shell 5, which allows the parasitic branch 3 to be located inside the injection-molded rear shell 5. In this scheme, the parasitic branch 3 can be injection-molded into the injection-molded rear shell 5 to achieve the installation of the parasitic branch 3.

[0143] Figure 46 is a schematic diagram of the radiation efficiency of the antenna system of the communication device in the embodiment of this application. The figure shows the antenna radiation efficiency of the communication device in the embodiment shown in Figures 43 and 44. It can be seen that the antenna system has high antenna efficiency.

[0144] There are several options for the grounding method of the parasitic branch 3 grounding terminal 31. In one specific embodiment, the grounding terminal 31 of the parasitic branch 3 is grounded to the metal shell 1. Alternatively, in another embodiment, the grounding terminal 31 can be grounded to the grounding plate 2, which can be a circuit board or other structure located inside the communication equipment. The specific grounding method of the parasitic branch 3 can be designed according to the product layout of the communication equipment.

[0145] Figure 47 is a schematic diagram of a communication device in one embodiment of this application, and Figure 48 is a partial schematic diagram of a communication device in one embodiment of this application. As shown in Figures 47 and 48, in one embodiment, the grounding terminal 31 of the parasitic branch 3 is connected to the floor 2, thereby grounding the parasitic branch 3. Alternatively, the grounding terminal 31 of the parasitic branch 3 can also be connected to the middle frame or the circuit board. The specific method for connecting the grounding terminal 31 of the parasitic branch 3 to the floor 2 is not limited; for example, the connection between the parasitic branch 3 and the middle frame can be achieved through a spring clip 6, an adapter piece 7, or a pin. For example, in the embodiment shown in Figure 48, the parasitic branch 3 is fixed to the middle frame with screws via the spring clip 6 and the adapter piece 7.

[0146] Figure 49 is a schematic diagram of the antenna efficiency of the communication device in the hand mold 4 state in the embodiment of this application. As shown in Figure 49, the antenna efficiency can be increased by grounding the parasitic branch 3 through the above scheme.

[0147] As shown in Figures 43 and 44, in one embodiment, an antenna is designed using the annular gap between the printed circuit board and the metal frame in the communication device. The metal frame corresponds to the aforementioned metal shell 1, and the printed circuit board corresponds to the floor 2. The metal shell 1 in this design includes a first feed point 13, a first ground point 11, a second ground point 12, and a fifth ground point 111.

[0148] In this application embodiment, there are multiple options for the specific arrangement of the parasitic branch 3. As shown in the accompanying drawings of the above embodiments, the parasitic branch 3 is a strip-shaped branch as an example. Figure 50 is a schematic diagram of the structure of a communication device in this application embodiment. As shown in Figure 50, in one embodiment of this application, the parasitic branch 3 may include a gap, thereby increasing the physical size of the parasitic branch 3 and enriching the design scheme of the parasitic branch 3.

[0149] Furthermore, Figure 51 is a schematic diagram of a communication device in an embodiment of this application. As shown in Figure 51, in this embodiment, the parasitic stub 3 may further include a second open end 34, which is located at the end of the grounding end 31 opposite to the first open end 32. In this scheme, the parasitic stub 3 has a relatively long length, which is beneficial for forming new high-frequency modes and for improving the bandwidth of the antenna system.

[0150] The extension length of the parasitic stub towards the second opening end 34 can be designed according to actual needs. As shown in Figure 51, in a specific embodiment, the second opening end 34 can be located at the second grounding point 12 of the first slot antenna 15 to enhance the influence of the parasitic stub 3 on the first slot antenna 15, thereby further improving the bandwidth of the antenna system. Of course, in some embodiments, the second opening end 34 can also be staggered from the second grounding point 12 of the first slot antenna. For example, the second opening end 34 is located on the side of the second grounding point facing the first grounding point, or the second opening end 34 can also be located on the side of the second grounding point away from the first grounding point.

[0151] Furthermore, similar to the first open end 32 of the parasitic branch 3, in this embodiment, the second open end 34 of the parasitic branch 3 is connected to a capacitor 33 and / or an inductor 33. Further, an adjustable capacitor 33 and / or an adjustable inductor 33 can be connected to the second open end 34 of the parasitic branch 3. Specific details and analysis can be found in the similar description of the first open end 32 of the parasitic branch 3, and will not be repeated here. In this scheme, the operating frequency can be adjusted collaboratively at the first open end 32 and the second open end 34, which is beneficial for enriching the operating frequency bands of the communication equipment and improving its communication bandwidth.

[0152] In this embodiment, the number of first slot antennas 15 and parasitic stubs 3 included in the communication device is not limited. For example, Figure 52 is a schematic diagram of a communication device in this embodiment. As shown in Figure 52, in this embodiment, the communication device may include at least two first slot antennas 15, each of which is connected to a parasitic stub 3. This enriches the operating frequency band of the communication device and improves its bandwidth.

[0153] Figure 53 is a schematic diagram of an antenna system of a communication device according to an embodiment of this application. As shown in Figure 53, in one embodiment, the parasitic stub 3 is grounded in the region between the grounding end 31 and the first opening end 32 through a capacitor or an inductor 33, or through a capacitor and an inductor. This allows adjustment of the electrical length of the parasitic stub 3 and the parasitic resonant frequency generated by the parasitic stub 3.

[0154] Furthermore, the parasitic branch 3 is grounded in the region between the grounding end 31 and the first opening end 32 via an adjustable capacitor or an adjustable inductor 33, or via both an adjustable capacitor and an adjustable inductor. By adjusting the capacitance of the adjustable capacitor 33 or the inductance of the adjustable inductor 33, the parasitic resonant frequency can be reconfigured, thereby enabling the resonant frequency of the antenna system to be reconfigured, thus forming a frequency-reconfigurable communication device.

[0155] Figure 54 is a schematic diagram of the return loss of an antenna system of a communication device in an embodiment of this application, and Figure 55 is a schematic diagram of the antenna efficiency of an antenna system of a communication device in an embodiment of this application. Taking the parasitic stub 3 connected to an adjustable inductor 33 between the grounding terminal 31 and the first opening terminal 32 as an example, the curves of return loss and antenna efficiency of the antenna system formed by adjusting the inductance value of the adjustable inductor 33 are shown in Figures 54 and 55. The lines in the figures show the curves corresponding to the 5nH, 10nH, 20nH and 40nH inductors 33 connected to the parasitic stub 3, respectively. By adjusting the inductance value of the adjustable inductor 33 connected to the grounding terminal 31 of the parasitic stub 3, the low-frequency resonant frequency of the antenna system is shifted, and the resonant frequency of the antenna system can be reconstructed. In addition, the antenna efficiency of the antenna system can be improved.

[0156] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A communication device, characterized in that, The device includes a metal shell, a floor, and parasitic branches. The metal shell includes a first grounding point, a second grounding point, and a first feed point. The first grounding point and the second grounding point are respectively grounded. The gap between the metal shell and the floor between the first grounding point and the second grounding point is a first gap, forming a first gap antenna. The first feed point is used to feed the first gap antenna. The parasitic stub extends along the extension direction of the first slot antenna and is fed through the first slot antenna. The parasitic stub includes a ground end and a first opening end. Along the extending direction, the grounding end is located in the middle of the first gap, and the first opening end is located at the first grounding point.

2. The communication device as described in claim 1, characterized in that, The electrical length of the parasitic branch is λ / 4, where λ is the wavelength of the parasitic branch radiation signal in free space.

3. The communication device as described in claim 1 or 2, characterized in that, The grounding end of the parasitic branch is connected to the metal shell, or the grounding end is connected to the floor.

4. The communication device according to any one of claims 1 to 3, characterized in that, The first open end of the parasitic branch is connected to a capacitor and / or an inductor.

5. The communication device as described in claim 4, characterized in that, The first open end of the parasitic branch is connected to an adjustable capacitor and / or an adjustable inductor.

6. The communication device according to any one of claims 1 to 3, characterized in that, The grounding terminal of the parasitic branch is connected to a capacitor and / or an inductor.

7. The communication device as described in claim 6, characterized in that, The grounding terminal of the parasitic branch is connected to an adjustable capacitor and / or an adjustable inductor.

8. The communication device according to any one of claims 1 to 7, characterized in that, The metal shell also includes a third grounding point, a fourth grounding point, and a second feed point. The third grounding point and the fourth grounding point are respectively grounded. The gap between the metal shell and the ground plane between the third grounding point and the fourth grounding point is a second gap, forming a second gap antenna. The second feed point is used to feed the second gap antenna.

9. The communication device according to any one of claims 1 to 8, characterized in that, The communication device includes a rear shell, which is fixed to the metal shell, and the parasitic branch is disposed on the rear shell.

10. The communication device as described in claim 9, characterized in that, The rear shell is an injection-molded rear shell, and the parasitic branch is located inside the injection-molded rear shell.

11. The communication device according to any one of claims 1 to 8, characterized in that, The parasitic branch is at least one of steel sheet, flexible circuit board, copper foil, silver paste or conductive fiber.

12. The communication device according to any one of claims 1 to 8, characterized in that, The parasitic branch also includes a second open end, which is located at the end of the grounding end opposite to the first open end.

13. The communication device as described in claim 12, characterized in that, The second open end is located at the second grounding point.

14. The communication device as described in claim 12 or 13, characterized in that, The second open end of the parasitic branch is connected to a capacitor and / or an inductor.

15. The communication device as described in claim 14, characterized in that, The second open end of the parasitic branch is connected to an adjustable capacitor and / or an adjustable inductor.

16. The communication device according to any one of claims 1 to 15, characterized in that, The parasitic branch is grounded in the region between the grounding end and the first open end via a capacitor and / or an inductor.

17. The communication device as described in claim 16, characterized in that, The parasitic branch is grounded in the region between the grounding end and the first open end via an adjustable capacitor and / or an adjustable inductor.

18. The communication device according to any one of claims 1 to 17, characterized in that, It includes at least two of the first slot antennas, each of which is connected to the parasitic branch.

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