CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage of International Application No. PCT/CN2017/078623, filed on Mar. 29, 2017, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

This application relates to communications technologies, and in particular, to an antenna and a terminal device.

BACKGROUND

With development of communications technologies, a terminal device such as a mobile phone or a tablet computer usually has wireless communication functions such as cellular communication, Wireless Fidelity (Wireless Fidelity, Wi-Fi), and Bluetooth (Bluetooth).

To meet a requirement for a light and thin terminal device, an antenna is usually built in the device. In terms of housing materials, there may be a plastic housing, a metal housing, and the like. Due to an aesthetical requirement for appearance, a terminal device with a metal housing becomes increasingly popular because the metal housing has advantages in terms of, for example, texture, durability, and service life. However, because the metal housing shields an electromagnetic wave, a built-in antenna of the terminal device cannot receive/send a signal. To ensure normal communication of the terminal device, currently, a slot or groove may be provided on up and down edge components of the metal housing to form a slot antenna.

However, because an end of the slot antenna is usually bent to a longer side of the metal housing, when the terminal device is held in hand, antenna performance is likely to attenuate, and consequently communication performance deteriorates.

SUMMARY

Embodiments of this application provide an antenna and a terminal device, so as to reduce antenna performance attenuation caused by holding the terminal device in hand, and improve communication performance.

According to a first aspect, an embodiment of this application provides an antenna, including a metal frame and at least one resonating structure, where the metal frame is provided with a slot to form a first radiating element and a second radiating element on the metal frame;

the first radiating element includes at least one radiation arm, and each radiation arm is connected to a feedpoint of a terminal device on which the antenna is located; and

the second radiating element includes at least one suspended radiation arm, each resonating structure includes one suspended radiation arm and a resonating component, the suspended radiation arm is connected to the resonating component, and the resonating component is further connected to a ground point of the terminal device.

The antenna provided in this embodiment of this application may enable one low-frequency bandwidth radiator to work even if another low-frequency bandwidth radiator is held in hand, thereby effectively improving antenna efficiency in a low-frequency operating band when the terminal device is held in hand, reducing antenna performance attenuation, and improving communication performance.

Optionally, the resonating component includes an inductance component, the suspended radiation arm is connected to the inductance component, and the inductance component is further connected to the ground point.

Optionally, the resonating component includes a capacitance component, the suspended radiation arm is connected to the capacitance component, and the capacitance component is further connected to the ground point.

Optionally, the resonating component includes an inductance component and a capacitance component, the inductance component is connected to the capacitance component, the inductance component is further connected to the suspended radiation arm, and the capacitance component is further connected to the ground point.

Optionally, the inductance component is an adjustable inductance component, and/or the capacitance component is an adjustable capacitance component.

In this embodiment of this application, antennas of different structures are provided when a plurality of different resonating structures are included, and an inductance component and/or a capacitance component of a resonating component may be configured as a component having a variable parameter value, so as to implement resonating structure switching between different resonance frequencies, thereby improving antenna radiation efficiency on each resonance frequency.

Optionally, the resonating component includes a first inductance component, a second inductance component, a first switch, and a second switch, the first inductance component is connected to the first switch, the second inductance component is connected to the second switch, the first inductance component and the second inductance component are further connected to the suspended radiation arm, and the first switch and the second switch are further connected to the ground point.

The antenna provided in this embodiment of this application can make an adjustment between different switch states, so as to implement resonating structure switching between different resonance frequencies, thereby improving antenna radiation efficiency on each resonance frequency.

Optionally, a shortest radiation arm in the first radiating element is further connected to a third inductance component and a fourth inductance component that are connected in parallel, the third inductance component is further connected to the ground point of the terminal device by using a third switch component, and the fourth inductance component is further connected to the ground point of the terminal device by using a fourth switch component.

In the antenna provided in this embodiment, antenna efficiency reduction caused when the antenna switches between different frequency bands in a low-frequency operating band can be effectively lessened.

Optionally, the third inductance component is further connected to a first capacitance component in parallel, and the fourth inductance component is further connected to the second capacitance component in parallel.

Optionally, a difference between a capacitance of the first capacitance component and an equivalent capacitance generated when the third switch is in a disconnected state is less than or equal to a preset value; and

a difference between a capacitance of the second capacitance component and an equivalent capacitance generated when the fourth switch is in a disconnected state is less than or equal to a preset value.

The antenna in this embodiment of this application can further filter out a spurious wave.

Optionally, the slot is a PI-shaped slot or a U-shaped slot.

According to a second aspect, an embodiment of this application further provides a terminal device, including a printed circuit board PCB and an antenna, where the PCB includes a radio frequency processing unit and a baseband processing unit, the antenna is any one of the foregoing antennas, each radiation arm in the first radiating element in the antenna is connected to a feedpoint on the radio frequency processing unit, and the radio frequency processing unit is connected to the baseband processing unit;

the antenna is configured to transmit a received radio signal to the radio frequency processing unit, or send a transmit signal of the radio frequency processing unit;

the radio frequency processing unit is configured to: after processing the radio signal received by the antenna, send the radio signal to the baseband processing unit; or after processing a signal sent by the baseband processing unit, send the signal by using the antenna; and

the baseband processing unit is configured to process the signal sent by the radio frequency processing unit.

According to the antenna and the terminal device provided in the embodiments of this application, the antenna may include the metal frame and the at least one resonating structure. The metal frame is provided with the slot to form the first radiating element and the second radiating element on the metal frame. The first radiating element includes the at least one radiation arm, and each radiation arm is connected to the feedpoint of the terminal device on which the antenna is located. The second radiating element includes the at least one suspended radiation arm. Each resonating structure includes the suspended radiation arm and the resonating component, and the suspended radiation arm is connected to the ground point of the terminal device by using the resonating component. The resonating structure is disposed in the antenna, so that in addition to a low-frequency bandwidth radiator included in the at least one radiation arm, the antenna may further include a low-frequency bandwidth radiator formed by the resonating structure. Therefore, even if one low-frequency bandwidth radiator is held in hand, another low-frequency bandwidth radiator may work, thereby effectively improving antenna efficiency in low-frequency bandwidth when the terminal device is held in hand, reducing antenna performance attenuation, and improving communication performance.

