Patent Description:
Development of mobile communications technologies promotes application of a multi-input multi-output (multi input multi output, MIMO) antenna technology, such as a wireless fidelity multi-input multi-output (wireless fidelity MIMO, Wi-Fi MIMO) antenna, on terminals. Antennas multiply in quantity, covering increasingly more frequency bands. However, a recent terminal design tends to have a higher screen-to-body ratio, more multimedia devices, and a larger battery capacity, resulting in sharp compression of antenna space. How to deploy multiple antennas in limited design space is a challenging question. In addition, an industrial design (industry design, ID), such as a metal ID or a bezel-less screen ID, of a terminal product needs to be considered during antenna layout, further increasing difficulty of the antenna layout.

Existing MIMO antenna technologies are classified into two types: a stacked antenna and a compact dual-antenna pair.

The stacked antenna is placing together some basic types of antenna units, such as a monopole, a dipole, and a slot, with a combination of some decoupling technologies like neutralization wires and choke slots, to form multiple antennas. This MIMO antenna has a complex design, occupies a large clearance, and is difficult to expand and include more antenna units.

The compact dual-antenna pair is placing two antenna units within a small-scale range, and isolation between the dual-antenna pair is improved by using self-decoupling or orthogonal polarization. This is a modular design solution and easy to expand and include more antenna units. This MIMO antenna array is simple in design, but inapplicable to a terminal with a metal ID because currently only a non-metal ID solution is available. <CIT> relates to an antenna device, which is applied to a terminal having a substrate and a conductive housing. <CIT> relates to a split ring resonator (SRR) antenna. <CIT> relates to a mobile device with a multiple-antenna system.

Embodiments of the present invention provide an antenna apparatus with a simple structure, to implement a multi-antenna structure on a terminal with a metal frame or an all-metal ID.

According to a first aspect, this application provides an antenna apparatus applied to a terminal. The terminal may include a metal frame, a printed circuit board PCB, a PCB floor, and a rear cover. The metal frame may be disposed at edges of the PCB floor, the PCB floor may be disposed between the PCB and the rear cover, and the PCB floor may be used to ground an electronic component carried on the PCB. The antenna apparatus may include: a split antenna formed by a split provided on the metal frame, and a slot antenna formed by a slot connecting to the split. The slot may be connected to the split on one side of the slot, and another side of the slot may touch the PCB floor. Specifically, the slot may be connected to the split at a middle position on one side of the slot.

A first feeding network may be connected to two sides of the split. The first feeding network may be used to excite the antenna apparatus to generate a first radiation mode. A primary radiator of the first radiation mode is the slot. A half wavelength in-phase electric field is distributed over the slot. A second feeding network may be further connected to one side of the split. The second feeding network may be used to excite the antenna apparatus to generate a second radiation mode. A primary radiator of the second radiation mode is the PCB floor. An in-phase current loop is distributed around the slot. A polarization direction of the first radiation mode is orthogonal to a polarization direction of the second radiation mode.

In other words, the antenna apparatus may have two radiation modes: the first radiation mode and the second radiation mode. The first radiation mode may be a half-wavelength slot mode to be mentioned in the embodiments, and the second radiation mode may be an open slot mode (also referred to as an in-phase current loop mode) to be mentioned in the embodiments.

In the first radiation mode, the half wavelength in-phase electric field is distributed over the slot. In this case, the slot may be used as a primary radiator, and a polarization direction is a negative X direction of a horizontal direction of the slot (for an antenna structure shown in <FIG>) or a Z direction of the slot (for an antenna structure shown in <FIG>). In other words, the first radiation mode may generate radiation by using the slot.

In the second radiation mode, the split divides the slot into two slots on two sides of the split. Both the slots can operate in a <NUM>/<NUM> wavelength mode. From one end of the slot to the other end, distribution of an electric field is as follows: The electric field is changed from zero to a maximum value, a direction of the electric field is reversed after passing through the split, and then the electric field changes from a reverse maximum value to zero. The current forms an in-phase current loop around the slot, to effectively excite the PCB floor to generate radiation. In other words, the second radiation mode may excite the PCB floor to generate radiation by using the split. In this case, the PCB floor may be a primary radiator, and a polarization direction is a negative Y direction.

It can be learned that the polarization directions of the primary radiators in the two radiation modes are orthogonal, to be specific, the polarization direction of the slot and the polarization direction of the PCB floor are orthogonal, to achieve high isolation. In addition, the antenna apparatus can provide multi-antenna in the split, with simple structure and modular design, it is easy to expand. Especially when the slot is provided on the metal frame, the antenna apparatus may be implemented as a zero-clearance co-frequency dual-antenna pair or a zero-clearance multi-antenna of another specification applicable to a terminal with an all-metal ID.

With reference to the first aspect, in some embodiments, the rear cover may be a rear cover made of an insulating material, for example, a glass rear cover or a plastic rear cover. Alternatively, the rear cover may be a metal rear cover. If the terminal is a terminal with an all-metal ID, the rear cover is a metal rear cover.

With reference to the first aspect, in some embodiments, the slot may be a slot provided on the PCB floor, or may be a slot provided on the metal frame. An opening direction of the slot may be consistent with an extension direction of the metal frame.

With reference to the first aspect, in some embodiments, the first feeding network may be specifically implemented as follows:.

The first feeding network may include feeding points that are separately disposed on two sides of the split on the metal frame: a first feeding point and a second feeding point. The first feeding point is disposed on one side of the split, and the second feeding point is disposed on the other side of the split. The first feeding network may further include a first feeding line and a first feeding port (port <NUM>). The first feeding line may be a microstrip or another wire. Alternatively, the first feeding line may cross the split and may be used to connect the first feeding port and the feeding points on two sides of the split. Alternatively, the first feeding line may cross the split. This can excite the slot to generate the half wavelength in-phase electric field distributed over the slot.

The first feeding line may use a symmetric feeding line structure, so that electric potentials of the first feeding point and the second feeding point can be equal, and the two sides of the split are equipotential.

A matching network may be designed at the first feeding port (port <NUM>), and the matching network may be used to adjust (by adjusting an antenna transmit coefficient, impedance, or the like) a frequency band range covered by the slot.

With reference to the first aspect, in some embodiments, the second feeding network may be specifically implemented as follows:.

The second feeding network may include a third feeding point disposed on one side of the split on the metal frame, a second feeding line, and a second feeding port (port <NUM>). The second feeding line may be a microstrip or another wire. The second feeding line may be used to connect the second feeding port and the third feeding point. The second feeding line may cross the split, to excite the split to generate an electric field distributed over the split, finally form the in-phase current loop around the slot, and effectively excite the PCB floor. In this case, the PCB floor may be used as a primary radiator of the antenna structure to generate radiation.

A matching network may be designed at the second feeding port (port <NUM>), and the matching network may be used to adjust (by adjusting an antenna transmit coefficient, impedance, or the like) a frequency band range covered by the PCB floor.

With reference to the first aspect, in some embodiments, a resonance generated when the antenna apparatus operates in the half-wavelength mode and excites the slot antenna and a resonance generated when the antenna apparatus operates in the in-phase current loop mode and excites the PCB floor may be in a same frequency band. In other words, the antenna apparatus may be a co-frequency dual-antenna pair.

Optionally, the antenna apparatus may be specifically a Sub-<NUM> dual-antenna pair whose operating frequency ranges from <NUM> to <NUM>, or the same frequency band is a Sub-<NUM> frequency band. Optionally, the antenna apparatus may be specifically a co-frequency dual Wi-Fi antenna pair, for example, a dual Wi-Fi antenna pair for a <NUM> frequency band, or the same frequency band is a Wi-Fi frequency band, for example, a <NUM> Wi-Fi frequency band. This is not limited thereto. The antenna apparatus may be alternatively a co-frequency dual-antenna pair for another frequency band.

With reference to the first aspect, in some embodiments, when operating in the half-wavelength mode, the antenna apparatus may excite the slot to generate a resonance for a first frequency band, and when operating in the in-phase current loop mode, the antenna apparatus may excite the PCB floor to generate a resonance for a second frequency band.

Optionally, the first frequency band may include a Wi-Fi frequency band, and the second frequency band may include a Wi-Fi frequency band and a GPS frequency band. For example, the antenna apparatus may excite the slot to generate a <NUM> Wi-Fi resonance in the half-wavelength mode (the first frequency band is a <NUM> Wi-Fi frequency band), and excite the PCB floor to generate a GPS L1 resonance and a <NUM> Wi-Fi resonance in the in-phase current loop mode (the second frequency band includes a <NUM> Wi-Fi frequency band and a GPS L1 frequency band). This is not limited thereto. The first frequency band and the second frequency band may be alternatively other frequency bands. For example, the antenna structure may excite the slot to generate a <NUM> Wi-Fi resonance in the half-wavelength mode (the first frequency band is a <NUM> Wi-Fi frequency band), and excite the PCB floor to generate a GPS L5 resonance and a <NUM> Wi-Fi resonance in the in-phase current loop mode (the second frequency band includes a <NUM> Wi-Fi frequency band and a GPS L5 frequency band).

According to a second aspect, this application provides a terminal. The terminal may include a metal frame, a printed circuit board PCB, a PCB floor, a rear cover, and the antenna apparatus described in the first aspect.

To describe the technical solutions in the embodiments of this application more clearly, the following illustrates the accompanying drawings in the embodiments of this application.

Technical solutions according to this application are applicable to a terminal that uses one or more of the following MIMO communications technologies: a long term evolution (long term evolution, LTE) communications technology, a Wi-Fi communications technology, a <NUM> communications technology, a Sub-<NUM> communications technology, and other future MIMO communications technologies. In this application, the terminal may be an electronic device such as a mobile phone, a tablet, or a personal digital assistant (personal digital assistant, PDA).

<FIG> shows an example of an internal environment of a terminal on which an antenna design solution according to this application is based. As shown in <FIG>, the terminal may include a display screen <NUM>, a printed circuit board PCB <NUM>, a PCB floor <NUM>, a metal frame <NUM>, and a rear cover <NUM>. The display screen <NUM>, the printed circuit board PCB <NUM>, the PCB floor <NUM>, and the rear cover <NUM> may be disposed at different layers. The layers may be parallel to each other. A plane on which each layer is located may be referred to as an X-Y plane, and a direction perpendicular to the X-Y plane is a Z direction. In other words, the display screen <NUM>, the printed circuit board PCB <NUM>, the PCB floor <NUM>, and the rear cover <NUM> may be distributed in a layered manner in the Z direction.

The printed circuit board PCB <NUM> may be an FR-<NUM> dielectric board, or may be a Rogers (Rogers) dielectric board, or may be a Rogers and FR-<NUM> hybrid dielectric board, or the like. Herein, FR-<NUM> is a grade designation for a flame-resistant material, and the Rogers dielectric board is a high frequency board.

The rear cover <NUM> may be a rear cover made of an insulating material, for example, a glass rear cover or a plastic rear cover. Alternatively, the rear cover <NUM> may be a metal rear cover. If the terminal shown in <FIG> is a terminal with an all-metal ID, the rear cover <NUM> is a metal rear cover.

The PCB floor <NUM> is grounded, and may be disposed between the printed circuit board PCB <NUM> and the rear cover <NUM>. The PCB floor <NUM> may also be referred to as a PCB baseboard. Specifically, the PCB floor <NUM> may be a layer of metal etched on the surface of the PCB <NUM>. This layer of metal may be connected to a metal middle frame (not shown) by using a series of metal springs, and is integrated with the metal middle frame. The PCB floor <NUM> may be used to ground an electronic component carried on the printed circuit board PCB <NUM>. Specifically, the electronic component carried on the printed circuit board PCB <NUM> may be grounded by connecting to the PCB floor <NUM>, to prevent an electric shock of a user or a device damage.

The metal frame <NUM> may be disposed at edges of the printed circuit board PCB <NUM> and the PCB floor <NUM>, and may cover, from a side, the printed circuit board PCB <NUM> and the PCB floor <NUM> that are between the rear cover <NUM> and the display screen <NUM>, to achieve dust-proof and waterproof purposes. In an implementation, the metal frame <NUM> may include four metal edges, and the four metal edges may be looped around the display screen <NUM>, the printed circuit board PCB <NUM>, the PCB floor <NUM>, and the rear cover <NUM>. In another implementation, the metal frame <NUM> may include only two metal edges, and the two metal edges may be disposed on two sides of the display screen <NUM>, the printed circuit board PCB <NUM>, the PCB floor <NUM>, and the rear cover <NUM> in the Y direction. This is not limited to the two implementations. Alternatively, the metal frame <NUM> may present another design style, for example, a metal frame <NUM> with a single metal edge. This is not limited in this application.

Based on the internal environment of the terminal shown in <FIG>, this application provides a multi-antenna design solution applicable to a terminal with a metal frame and a multi-antenna design solution applicable to a terminal with an all-metal ID.

A main design idea of the multi-antenna design solution according to this application may include: opening a split on the metal frame <NUM>, and forming a multi-antenna structure by using a split antenna formed by the split and a slot antenna formed by a slot communicating with the split. The slot may be connected to the split at a middle position on one side of the slot, and another side of the split may touch the PCB floor.

In some embodiments, the slot may be provided on the PCB floor <NUM>, as shown in <FIG>.

<FIG> is a view for observing the antenna structure in the Z direction, and <FIG> is a view for observing the antenna structure in the negative X direction. As shown in <FIG>, the slot may be a slot <NUM> provided on the PCB floor <NUM>. An opening direction of the slot <NUM> may be consistent with an extension direction of the metal frame <NUM>. The slot <NUM> may be connected to a split <NUM> provided on the metal frame <NUM> at a middle position on one side of the slot <NUM>.

In other embodiments, the slot may be provided on the metal frame <NUM>, as shown in <FIG> is a view for observing the antenna structure in the Z direction, and <FIG> is a view for observing the antenna structure in the negative X direction. As shown in <FIG>, the slot may be a slot <NUM> provided on the metal frame <NUM>. An opening direction of the slot <NUM> is consistent with an extension direction of the metal frame <NUM>. The slot <NUM> may be connected to a split <NUM> provided on the metal frame <NUM> at a middle position on one side of the slot <NUM>. Another side of the slot <NUM> may touch the PCB floor <NUM>.

Two radiation modes of the antenna structure according to this application may be shown in <FIG>, <FIG>. <FIG> show radiation modes of the antenna structure shown in <FIG>. <FIG> show radiation modes of the antenna structure shown in <FIG>.

The antenna structure according to this application may have two radiation modes: a half-wavelength slot mode (shown in <FIG> and <FIG>) and an open slot mode (also referred to as an in-phase current loop mode) (shown in <FIG> and <FIG>). In this application, the half-wavelength mode may be referred to as a first radiation mode, and the open slot mode (also referred to as an in-phase current loop mode) may be referred to as a second radiation mode.

In the half-wavelength slot mode, a half wavelength in-phase electric field is distributed over the slot <NUM>. Two sides of the split <NUM> may be equipotential. The split <NUM> does not affect a resonance generated by the slot <NUM> as a slot antenna (whose two ends are closed), and the slot antenna whose two ends are closed usually generates a resonance in the half-wavelength mode. As shown in <FIG> and <FIG>, current distribution over the slot <NUM> may be typical current distribution of the slot antenna in the half-wavelength mode. In this case, the slot <NUM> may be used as a primary radiator, and a polarization direction is a negative X direction of a horizontal direction of the slot <NUM> (for the antenna structure shown in <FIG>) or a Z direction of the slot <NUM> (for the antenna structure shown in <FIG>).

That is to say, the half-wavelength slot mode may excite the slot <NUM> to generate a half wavelength in-phase electric field distributed over the slot <NUM> (distributed over the slot <NUM>). In this case, the slot <NUM> may be used as a primary radiator of the antenna structure to generate radiation. To be specific, the half-wavelength slot mode can generate radiation by using the slot.

In the open slot mode (or referred to as an in-phase current loop mode), the split <NUM> divides the slot <NUM> into two slots on two sides of the split <NUM>. Both the slots can operate in a <NUM>/<NUM> wavelength mode. From one end of the slot <NUM> to the other end, distribution of an electric field is as follows: The electric field is changed from zero to a maximum value, a direction of the electric field is reversed after passing through the split <NUM>, and then the electric field changes from a reverse maximum value to zero. As shown in <FIG> and <FIG>, the current forms an in-phase current loop around the slot <NUM>, to effectively excite the PCB floor to generate radiation. In other words, the in-phase current loop mode may excite the PCB floor to generate radiation by using the split. In this case, the PCB floor <NUM> may be a primary radiator, and a polarization direction is a negative Y direction.

That is to say, the open slot mode (or referred to as an in-phase current loop mode) may excite the split <NUM> to generate an in-phase current loop around the slot <NUM>, thereby effectively exciting the PCB floor <NUM> to generate radiation. In this case, the PCB floor <NUM> may be used as a primary radiator of the antenna structure to generate radiation.

It can be learned that polarization directions of the two radiation modes are orthogonal, to be specific, the polarization direction of the primary radiator slot <NUM> in the first radiation mode and the polarization direction of the primary radiator PCB floor <NUM> in the second radiation mode are orthogonal, to achieve high isolation. In specific implementation, the antenna structure (as shown in <FIG> or in <FIG>) according to this application can operate in the two radiation modes by using a proper feeding network. In this way, a dual-antenna pair can be obtained in the split <NUM>, and a <NUM> x <NUM> MIMO specification can be implemented. Further, some matching circuits (such as tuning switches) or switch circuits are combined to adjust the length of the slot <NUM>, so that more frequency bands can be covered. In addition, the antenna design solution is a modular design, and can be easy to expand and include more antenna units.

In addition, the antenna design solution according to this application is applicable to a terminal with a metal frame. The slot <NUM> in the antenna structure shown in <FIG> is provided on the metal frame <NUM>. In this case, the antenna structure may radiate a signal outward by using the slot <NUM>, and no clearance needs to be reserved on the PCB <NUM>. The antenna structure is applicable to a terminal with an all-metal ID.

The following describes in detail antenna structures according to the embodiments of this application.

<FIG> and <FIG> show an example of an antenna structure according to Embodiment <NUM>. <FIG> is a schematic diagram of an antenna model including a PCB dielectric board, and <FIG> is a schematic diagram of an antenna structure after the PCB dielectric board is hidden. A PCB floor <NUM> may be disposed at the bottom of a first PCB dielectric board <NUM> (the PCB <NUM> in <FIG>). Alternatively, a second PCB dielectric board <NUM> may be disposed close to a metal frame <NUM>. As shown in <FIG> and <FIG>, the antenna structure may include a split <NUM> provided on the metal frame <NUM> and a slot <NUM> provided on the PCB floor <NUM>. The slot <NUM> may be connected to the split <NUM> at a middle position on one side of the slot <NUM>.

A first feeding network <NUM> may be connected to two sides of the split <NUM>. The first feeding network <NUM> may be specifically printed on the first PCB dielectric board <NUM> and the second PCB dielectric board <NUM>. The first feeding network <NUM> may be used to excite the antenna structure to operate in the half-wavelength slot mode, to be specific, excite the antenna structure to generate a half wavelength in-phase electric field distributed over the slot <NUM>. In this case, the slot <NUM> is used as a primary radiator to generate radiation.

Specifically, the first feeding network <NUM> may include feeding points that are disposed on two sides of the split <NUM> on the metal frame <NUM>: a first feeding point <NUM>-<NUM> and a second feeding point <NUM>-<NUM>. The first feeding point <NUM>-<NUM> is disposed on one side of the split <NUM>, and the second feeding point <NUM>-<NUM> is disposed on the other side of the split <NUM>. The first feeding network <NUM> may further include a first feeding line <NUM>-<NUM> and a first feeding port <NUM>-<NUM> (port <NUM>). The first feeding line <NUM>-<NUM> may be a microstrip or another wire. The first feeding line <NUM>-<NUM> may be used to connect the first feeding port <NUM>-<NUM> and the feeding points on the two sides of the split <NUM>. Specifically, an end of the first feeding line <NUM>-<NUM> may pass through the second PCB dielectric board <NUM> (in a manner of drilling a hole) and be connected to the feeding points on the two sides of the split <NUM>. The first feeding line <NUM>-<NUM> may use a symmetric feeding line structure, for example, a T-shaped feeding line structure shown in <FIG> and <FIG>. In this way, electric potentials of the first feeding point <NUM>-<NUM> and the second feeding point <NUM>-<NUM> can be equal, so that the two sides of the split <NUM> are equipotential. Therefore, the split <NUM> may not affect a resonance generated by the slot <NUM> as a slot antenna (whose two ends are closed). Alternatively, the first feeding line <NUM>-<NUM> may cross the slot <NUM>, to excite the slot <NUM> to generate a half wavelength in-phase electric field distributed over the slot <NUM>. In this case, the slot <NUM> may be used as a primary radiator of the antenna structure to generate radiation. A matching network may be designed at the first feeding port <NUM>-<NUM> (port <NUM>), and the matching network may be used to adjust (by adjusting an antenna transmit coefficient, impedance, or the like) a frequency band range covered by the slot antenna formed by the slot <NUM>.

A second feeding network <NUM> may be connected to one side of the split <NUM>. The second feeding network <NUM> may be specifically printed on the second PCB dielectric board <NUM>. The second feeding network <NUM> may be used to excite the antenna structure to operate in the open slot mode (or referred to as an in-phase current loop mode), to be specific, to excite the antenna structure to generate an in-phase current loop around the slot <NUM>.

Specifically, the second feeding network <NUM> may include a third feeding point <NUM>-<NUM> disposed on one side of the split <NUM> on the metal frame, a second feeding line <NUM>-<NUM>, and a second feeding port <NUM>-<NUM> (port <NUM>). The second feeding line <NUM>-<NUM> may be a microstrip or another wire. The second feeding line <NUM>-<NUM> may be used to connect the second feeding port <NUM>-<NUM> and the third feeding point <NUM>-<NUM>. Specifically, an end of the second feeding line <NUM>-<NUM> may pass through the second PCB dielectric board <NUM> (in a manner of drilling a hole) and be connected to the third feeding point <NUM>-<NUM>. The second feeding line <NUM>-<NUM> may cross the split <NUM>, to excite the split <NUM> to generate an electric field distributed over the split <NUM>, finally form an in-phase current loop around the slot <NUM>, and effectively excite the PCB floor <NUM>. In this case, the PCB floor <NUM> may be used as a primary radiator of the antenna structure to generate radiation. A matching network may be designed at the second feeding port <NUM>-<NUM> (port <NUM>), and the matching network may be used to adjust (by adjusting an antenna transmit coefficient, impedance, or the like) a frequency band range covered by the PCB floor <NUM>.

It can be learned from the foregoing content that a polarization direction of the antenna structure when the antenna structure operates in the half-wavelength slot mode is orthogonal to a polarization direction when the antenna structure operates in the open slot mode (or referred to as an in-phase current loop mode), thereby having good isolation.

The antenna structure according to Embodiment <NUM> may be a Sub-<NUM> dual-antenna pair whose operating frequency ranges from <NUM> to <NUM>. In an optional implementation, an overall size of the terminal may be <NUM> x <NUM> x <NUM>, the first PCB dielectric board <NUM> may be an FR-<NUM> dielectric board with a thickness of <NUM>, a size of the slot <NUM> may be <NUM> x <NUM>, a size of the split <NUM> may be <NUM> x <NUM>, and the second PCB dielectric board <NUM> close to the metal frame <NUM> may be an FR-<NUM> dielectric board with a thickness of <NUM>.

<FIG> show a simulated S-parameter, an efficiency curve, and an envelope correlation coefficient of the Sub-<NUM> dual-antenna pair according to Embodiment <NUM>. Herein, <FIG> represents the simulated S-parameter, <FIG> represents the efficiency curve, and <FIG> represents the envelope correlation coefficient. In an optional implementation, the matching network designed at the first feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in parallel to a <NUM> nH inductor (L1) and then connected in series to a <NUM> nH inductor (L2), as shown in <FIG>. In an optional implementation, the matching network designed at the second feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in parallel to an <NUM> nH inductor (L3) and then connected in series to a <NUM> nH inductor (L4), as shown in <FIG>. All the inductors mentioned herein may be lumped inductors, and may be ideal devices.

As shown in <FIG>, in a required operating frequency range of <NUM> to <NUM>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), a reflection coefficient is less than -<NUM> dB. For the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a reflection coefficient is less than - <NUM> dB. It can be learned that the antenna apparatus can cover the frequency range of <NUM> to <NUM> in the two modes. As shown in <FIG>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), a total efficiency is between -<NUM> and -<NUM>. For the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a total efficiency is between -<NUM> and -<NUM>. It can be learned that the radiation efficiencies of the antenna apparatus in the two modes are relatively high, and there is no obvious efficiency dent. Because the polarization directions of the antenna in the two modes are orthogonal, high isolation and a small envelope correlation coefficient are obtained. As shown in <FIG>, in a required operating frequency range of <NUM> to <NUM>, an envelope correlation coefficient is less than <NUM>, and isolation is better than -<NUM> dB. A symmetric structure used by the first feeding network <NUM> is highly conducive to improvement in isolation. Because the first feeding network <NUM> has a symmetric structure, when the first feeding port <NUM>-<NUM> (port <NUM>) feeds to excite the half-wavelength slot mode, electric field phases on two sides of the split <NUM> are the same, but when the second feeding port <NUM>-<NUM> (port <NUM>) feeds to excite the in-phase current loop mode, an electric field phase difference between two sides of the split <NUM> reaches <NUM>°. In this way, energy cannot be transferred between the first feeding port <NUM>-<NUM> (port <NUM>) and the second feeding port <NUM>-<NUM> (port <NUM>), providing a prerequisite for achieving high isolation.

The antenna structure according to Embodiment <NUM> can implement a dual-antenna pair for the Sub-<NUM> frequency band. The antenna structure is compact and has high isolation. The antenna structure shown in <FIG> and <FIG> for example may be alternatively implemented as a co-frequency high-isolation dual-antenna pair for a frequency band other than the Sub-<NUM> frequency band, and may be specifically set by adjusting sizes of the split <NUM> and the slot <NUM> in the antenna structure. For example, the antenna structure may be alternatively implemented as a co-frequency dual Wi-Fi antenna pair for a frequency band of <NUM>. The antenna structure is applicable to a terminal with a metal frame. Optionally, the antenna structure may also be applicable to a terminal with an all-metal ID, provided that a clearance is reserved for the antenna structure on the first PCB dielectric board <NUM>.

For an antenna structure according to Example <NUM>, refer to <FIG> and <FIG>. The antenna structure according to Embodiment <NUM> may be implemented as an antenna of a GPS L1 + <NUM> Wi-Fi MIMO specification. An operating frequency of the GPS L <NUM> is <NUM>, and an operating frequency of the <NUM> Wi-Fi MIMO ranges from <NUM> to <NUM>. In Embodiment <NUM>, an overall size of a terminal, a size of a first PCB dielectric board <NUM>, a size of a second PCB dielectric board <NUM>, and a size of a split <NUM> are all the same as corresponding designs in Embodiment <NUM>. Embodiment <NUM> is different from Embodiment <NUM> in that the size of the slot <NUM> in Embodiment <NUM> may be <NUM> x <NUM>, in other words, the slot <NUM> in Embodiment <NUM> is longer and wider than the slot <NUM> in Embodiment <NUM>. In addition, a structure and a form of a feeding network (a first feeding network <NUM> and a second feeding network <NUM>) in Embodiment <NUM> may be the same as those in Embodiment <NUM>, but because the size of the slot <NUM> changes, a size of each branch of the feeding network in Embodiment <NUM> changes, for example, a feeding branch across the slot <NUM> is longer.

<FIG> show a simulated S-parameter, an efficiency curve, and an envelope correlation coefficient of the antenna structure according to Embodiment <NUM>. Herein, <FIG> represents the simulated S-parameter, <FIG> represents the efficiency curve, and <FIG> represents the envelope correlation coefficient. In an optional implementation, a matching network designed at the first feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in series to a <NUM> nH inductor (L5) and then connected in parallel to a <NUM> pF capacitor (C1), to generate a <NUM> Wi-Fi operating frequency, as shown in <FIG>. In an optional implementation, a matching network designed at the second feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in series to a <NUM> nH inductor (L6), then connected in parallel to a <NUM> pF capacitor (C2), then connected in parallel to an <NUM> nH inductor (L7), and finally connected in series to a <NUM> pF capacitor (C3), to generate two frequencies: an operating frequency of GPS L1 and an operating frequency of <NUM> Wi-Fi, as shown in <FIG>. All the inductors and the capacitors mentioned herein may be lumped elements, and may be ideal devices.

As shown in <FIG>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), in a <NUM> Wi-Fi operating frequency range, a reflection coefficient is less than -<NUM> dB, in other words, the antenna structure can generate a <NUM> Wi-Fi resonance in the half-wavelength slot mode. As shown in <FIG>, for the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a GPS L1 resonance and a <NUM> Wi-Fi resonance may be generated. A reflection coefficient of the <NUM> Wi-Fi resonance is close to (less than -<NUM> dB) a reflection coefficient of the <NUM> Wi-Fi resonance in the half-wavelength slot mode. A transmit coefficient of the resonance at the operating frequency of the GPS L1 is less than -<NUM> dB. As shown in <FIG>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), in a <NUM> Wi-Fi operating frequency range, a total efficiency is between -<NUM> and -<NUM>. It can be learned that, the radiation efficiency of the resonance generated by the antenna apparatus in the half-wavelength slot mode in the <NUM> Wi-Fi operating frequency range is relatively high, and there is no obvious efficiency dent. As shown in <FIG>, for the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a GPS L1 resonance and a <NUM> Wi-Fi resonance may be generated. A total efficiency of the <NUM> Wi-Fi resonance is almost the same as (between -<NUM> to -<NUM>) a total efficiency of the <NUM> Wi-Fi resonance in the half-wavelength slot mode. A total efficiency of the resonance at the operating frequency of the GPS L1 is -<NUM>. It can be learned that in the in-phase current loop mode, the radiation efficiencies of the two resonances generated by the antenna apparatus in the <NUM> Wi-Fi operating frequency range and the GPS L1 operating frequency are relatively high, and there is no obvious efficiency dent. Because polarization directions of the antenna in the two modes are orthogonal, high isolation and a small envelope correlation coefficient are also obtained in the <NUM> Wi-Fi operating frequency range. As shown in <FIG>, in a required operating frequency range of <NUM> to <NUM>, an envelope correlation coefficient is less than <NUM>, and isolation is better than -<NUM> dB.

The antenna structure according to Embodiment <NUM> may implement an antenna of a GPS L1 + <NUM> Wi-Fi MIMO specification, and has high isolation. This is not limited thereto. The antenna structure may alternatively operate in another frequency band, for example, a GPS L5 (whose operating frequency is <NUM>) + <NUM> Wi-Fi MIMO operating frequency range, and may be specifically set by adjusting a size of the slot <NUM> in the antenna structure.

<FIG> and <FIG> show an example of an antenna structure according to Embodiment <NUM>. <FIG> is a schematic diagram of an antenna model including a PCB dielectric board, and <FIG> is a schematic diagram of an antenna structure after the PCB dielectric board is hidden. A PCB floor <NUM> may be disposed at the bottom of a first PCB dielectric board <NUM> (the PCB <NUM> in <FIG>). Alternatively, a second PCB dielectric board <NUM> may be disposed close to a metal frame <NUM>. As shown in <FIG> and <FIG>, the antenna structure may include a split <NUM> provided on the metal frame <NUM> and a slot <NUM> communicating with the split <NUM>. The slot <NUM> may be connected to the split <NUM> at a middle position on one side of the slot <NUM>. Embodiment <NUM> is different from Embodiment <NUM> in that the slot <NUM> in Embodiment <NUM> is provided on the metal frame <NUM>. In this way, the antenna structure may radiate a signal outward by using the slot <NUM> on the metal frame <NUM>, and no clearance needs to be reserved on the first PCB dielectric board <NUM> for the antenna structure, thereby implementing a zero-clearance antenna structure.

Specifically, the first feeding network <NUM> may include feeding points that are disposed on two sides of the split <NUM> on the metal frame <NUM>: a first feeding point <NUM>-<NUM> and a second feeding point <NUM>-<NUM>. The first feeding point <NUM>-<NUM> is disposed on one side of the split <NUM>, and the second feeding point <NUM>-<NUM> is disposed on the other side of the split <NUM>. The first feeding network <NUM> may further include a first feeding line <NUM>-<NUM> and a first feeding port <NUM>-<NUM> (port <NUM>). The first feeding line <NUM>-<NUM> may be a microstrip or another wire. The first feeding line <NUM>-<NUM> may be used to connect the first feeding port <NUM>-<NUM> and the feeding points on the two sides of the split <NUM>. Specifically, an end of the first feeding line <NUM>-<NUM> may pass through the second PCB dielectric board <NUM> (in a manner of drilling a hole) and be connected to the feeding points on the two sides of the split <NUM>. The first feeding line <NUM>-<NUM> may use a symmetric feeding line structure, for example, a T-shaped feeding line structure shown in <FIG> and <FIG>. In this way, electric potentials of the first feeding point <NUM>-<NUM> and the second feeding point <NUM>-<NUM> can be equal, so that the two sides of the split <NUM> are equipotential. Therefore, the split <NUM> may not affect a resonance generated by the slot <NUM> as a slot antenna (whose two ends are closed). Alternatively, the first feeding line <NUM>-<NUM> may cross the slot <NUM>, to excite the slot <NUM> to generate a half wavelength in-phase electric field distributed over the slot <NUM>. In this case, the slot <NUM> may be used as a primary radiator of the antenna structure to generate radiation. A matching network may be designed at the first feeding port <NUM>-<NUM> (port <NUM>), and the matching network may be used to adjust (by adjusting an antenna transmit coefficient, impedance, or the like) a frequency band range covered by the slot <NUM>.

The antenna structure according to Embodiment <NUM> may be a zero-clearance Sub-<NUM> dual-antenna pair applicable to a terminal with an all-metal ID, and an operating frequency of the dual-antenna pair ranges from <NUM> to <NUM>. In an optional implementation, an overall size of the terminal may be <NUM> x <NUM> x <NUM>, the first PCB dielectric board <NUM> may be an FR-<NUM> dielectric board with a thickness of <NUM>, a size of the slot <NUM> may be <NUM> xx <NUM>, a size of the split <NUM> may be <NUM> x <NUM>, and the second PCB dielectric board <NUM> close to the metal frame <NUM> may be an FR-<NUM> dielectric board with a thickness of <NUM>.

<FIG> show a simulated S-parameter, an efficiency curve, and an envelope correlation coefficient of the Sub-<NUM> dual-antenna pair according to Embodiment <NUM>. Herein, <FIG> represents the simulated S-parameter, <FIG> represents the efficiency curve, and <FIG> represents the envelope correlation coefficient. In an optional implementation, the matching network designed at the first feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in parallel to a <NUM> nH inductor (L8) and then connected in series to a <NUM> nH inductor (L9), as shown in <FIG>. In an optional implementation, the matching network designed at the second feeding port <NUM>-<NUM> (port <NUM>) may be first, at the port <NUM>, connected in parallel to a <NUM> pF capacitor (C4) and then connected in series to an <NUM> nH inductor (L10), as shown in <FIG>. All the inductors mentioned herein may be lumped inductors, and may be ideal devices.

As shown in <FIG>, in a required operating frequency range of <NUM> to <NUM>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), a reflection coefficient is less than -<NUM> dB. For the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a reflection coefficient is less than - <NUM> dB. It can be learned that the antenna apparatus can cover the frequency range of <NUM> to <NUM> in the two modes. As shown in <FIG>, for the half-wavelength slot mode excited by the first feeding port <NUM>-<NUM> (port <NUM>), a total efficiency is between -<NUM> and -<NUM>. For the in-phase current loop mode excited by the second feeding port <NUM>-<NUM> (port <NUM>), a total efficiency is between -<NUM> and -<NUM>. It can be learned that the radiation efficiencies of the antenna apparatus in the two modes are relatively high, and there is no obvious efficiency dent. Because the polarization directions of the antenna in the two modes are orthogonal, high isolation and a small envelope correlation coefficient are obtained. As shown in <FIG>, in a required operating frequency range of <NUM> to <NUM>, an envelope correlation coefficient is less than <NUM>, and isolation is better than -<NUM> dB.

The antenna structure according to Embodiment <NUM> is applicable to a terminal with a metal frame. The antenna structure may also be applicable to a terminal with an all-metal ID, and may be implemented as a zero-clearance antenna structure for the terminal with an all-metal ID. The antenna structure shown in <FIG> and <FIG> for example may be alternatively implemented as a zero-clearance co-frequency high-isolation dual-antenna pair for a frequency band other than the Sub-<NUM> frequency band, and may be specifically set by adjusting sizes of the split <NUM> and the slot <NUM> in the antenna structure. For example, the antenna structure may be alternatively implemented as a zero-clearance co-frequency dual Wi-Fi antenna pair for a frequency band of <NUM>. For another example, when the size of the slot <NUM> is the same as the size of the slot <NUM> in Embodiment <NUM>, the antenna structure shown in <FIG> and <FIG> for example may be alternatively implemented as a zero-clearance antenna of a GPS L1 + <NUM> Wi-Fi MIMO specification. For still another example, the antenna structure shown in <FIG> and <FIG> for example may be alternatively implemented as a zero-clearance antenna of a GPS L5 + <NUM> Wi-Fi MIMO specification. Unlimited to these examples, the antenna structure according to Embodiment <NUM> may be alternatively implemented as a zero-clearance multi-antenna structure of another specification.

The following describes extended implementations related to the foregoing embodiments.

In some embodiments, the length of the slot <NUM> may be adjusted with reference to a matching technology or a switch, so that the antenna structure can cover more frequency bands. For example, as shown in <FIG>, two sides of the slot <NUM> may be connected by using a tuning switch S <NUM>. When the tuning switch S1 is in a closed state, the length of the slot <NUM> decreases. In this case, the antenna structure may generate another resonance, and the another resonance may be different from a resonance generated by the antenna structure when the tuning switch S1 is turned off. In this way, the antenna structure shown in <FIG> for example can generate more resonances and cover more frequency bands. This is not limited to the example in <FIG>. In actual application, the length of the slot <NUM> may be adjusted with reference to another matching technology or switch. This is not limited in this application. <FIG> shows such an antenna structure as a simplified example, and does not reflect the metal frame <NUM>, the PCB floor <NUM>, and the like designed for the antenna structure.

The slot <NUM> may not have to be connected to the split <NUM> at the middle position on one side of the slot <NUM>.

In some embodiments, as shown in <FIG> for example, the split <NUM> may be connected to the slot <NUM> at a non-middle position on one side of the slot <NUM>. In this antenna structure, multiple antennas may be implemented at the split <NUM>, but isolation is not as high as those of the antenna structures described in Embodiment <NUM> to Embodiment <NUM>. <FIG> shows such an antenna structure as a simplified example, and does not reflect the metal frame <NUM>, the PCB floor <NUM>, and the like designed for the antenna structure.

The first feeding network <NUM> may alternatively use an asymmetric network structure.

In some embodiments, as shown in <FIG> for example, the first feeding network <NUM> may use an asymmetric network structure. For example, the feeding point <NUM>-<NUM> is disposed only on one side of the split <NUM>, and the feeding line <NUM>-<NUM> crosses the slot <NUM>. The first feeding network <NUM> may also excite the antenna structure to operate in the half-wavelength slot mode, to be specific, excite the slot <NUM> to act as a primary radiator to generate radiation. In this case, the antenna structure may also implement multiple antennas at the split <NUM>, but isolation is not as high as those of the antenna structures described in Embodiment <NUM> to Embodiment <NUM>.

It can be learned that, the antenna structures according to the embodiments of this application may form a combo antenna structure by using the split <NUM> on the metal frame of the terminal and the slot <NUM> communicating with the split <NUM>. A multi-antenna structure may be implemented at the split <NUM>. The antenna structures are applicable to a terminal with a metal frame or a terminal with an all-metal ID. In addition, the antenna has a simple structure and becomes easy to expand due to a modular design.

In this application, a wavelength in a wavelength mode (for example, a half wavelength mode) of an antenna may be a wavelength of a signal radiated by the antenna. For example, a half wavelength mode of a floating metal antenna may generate a resonance for a <NUM> frequency band. A wavelength in the half wavelength mode is a wavelength of a signal radiated by the antenna in the <NUM> frequency band. It should be understood that a wavelength of the radiated signal in the air may be calculated as follows: Wavelength = Speed of light/Frequency, where the frequency is a frequency of the radiated signal. A wavelength of the radiated signal in a medium may be calculated as follows: <MAT> , where <MAT> is a relative permittivity of the medium, and the frequency is a frequency of the radiated signal.

Claim 1:
An electronic device, comprising a metal frame (<NUM>), a printed circuit board PCB (<NUM>), a PCB floor (<NUM>), a rear cover (<NUM>), and an antenna apparatus, wherein
the metal frame is disposed at edges of the PCB floor, the PCB floor is disposed between the PCB and the rear cover, and the PCB floor is configured to ground an electronic component carried on the PCB; the antenna apparatus comprises: a split antenna formed by a split (<NUM>) provided on the metal frame such that the metal frame comprises two parts on either side of the split, and a slot antenna formed by a slot (<NUM>) connecting the split; and the slot is connected to the split on one side of the slot, and another side of the slot touches the PCB floor;
a first feeding network (<NUM>) is connected to two sides of the split, the first feeding network is configured to excite the antenna apparatus to generate a first radiation mode, a primary radiator of the first radiation mode is the slot, and a half wavelength in-phase electric field is distributed over the slot;
a second feeding network (<NUM>) is further connected to one side of the split, the second feeding network is configured to excite the antenna apparatus to generate a second radiation mode, a primary radiator of the second radiation mode is the PCB floor, and an in-phase current loop is distributed around the slot; and
a polarization direction of the first radiation mode is orthogonal to a polarization direction of the second radiation mode
wherein the slot antenna is formed by providing a slot on the metal frame.