CN113659309A

CN113659309A - Antenna device and electronic apparatus

Info

Publication number: CN113659309A
Application number: CN202010398777.3A
Authority: CN
Inventors: 张帅; 雍征东
Original assignee: Xidian University; Guangdong Oppo Mobile Telecommunications Corp Ltd
Current assignee: Xidian University; Guangdong Oppo Mobile Telecommunications Corp Ltd
Priority date: 2020-05-12
Filing date: 2020-05-12
Publication date: 2021-11-16

Abstract

The application provides an antenna device and an electronic apparatus. The antenna device includes: the antenna comprises a plurality of spaced antenna units, a plurality of decoupling networks, a decoupling transmission line and a ground layer. The decoupling networks correspond to the antenna units one by one, and each decoupling network comprises a closed loop structure and a first transmission line and a second transmission line which are connected to the closed loop structure; the closed-loop structure is provided with a first output port and a second output port, the first transmission line is used for being connected with the radio frequency chip, one end of the second transmission line is connected with the first output port, and the other end of the second transmission line is connected with the corresponding antenna unit; the decoupling transmission line is connected between the second output ports of the adjacent decoupling networks; the ground layer is overlapped with the decoupling networks at intervals, the ground layer is provided with a slot, and at least one part of the slot is overlapped with the closed loop structure. The electronic equipment comprises the antenna device.

Description

Antenna device and electronic apparatus

Technical Field

The present application relates to the field of antenna decoupling technology, and in particular, to an antenna device, an electronic device having the antenna device, and a decoupling method for the antenna device.

Background

An antenna can efficiently transmit and receive electromagnetic waves, and is an indispensable important component in a wireless communication system. However, with the advancement of scientific technology, it is difficult for a single antenna to meet the increasing performance requirements. In order to solve the problems of poor directivity, low radiation gain and the like of a single antenna unit, a plurality of antennas with the same radiation characteristics can be arranged according to a certain geometric structure to form an array antenna, so that the radiation performance of the antennas is enhanced, and a flexible directional diagram is generated to meet the requirements of different scenes.

Disclosure of Invention

An aspect of the present application provides an antenna apparatus, including: the antenna comprises a plurality of spaced antenna units, a plurality of decoupling networks, a decoupling transmission line and a ground layer. The decoupling networks correspond to the antenna units one by one, and each decoupling network comprises a closed loop structure and a first transmission line and a second transmission line which are connected to the closed loop structure; the closed-loop structure is provided with a first output port and a second output port, the first transmission line is used for being connected with the radio frequency chip, one end of the second transmission line is connected with the first output port, and the other end of the second transmission line is connected with the corresponding antenna unit; the decoupling transmission line is connected between the second output ports of the adjacent decoupling networks; the ground layer and the decoupling networks are overlapped at intervals, the ground layer is provided with a slot, and at least one part of the slot is overlapped with the closed loop structure.

Another aspect of the present application provides an electronic device including a housing, a display screen assembly, a radio frequency chip, and an antenna apparatus. The display screen assembly is connected with the shell and forms an accommodating space with the shell; the radio frequency chip is arranged in the accommodating space; and the antenna device is at least partially arranged in the accommodating space. The antenna device includes: the antenna comprises a plurality of spaced antenna units, a plurality of decoupling networks, a decoupling transmission line and a ground layer. The decoupling networks correspond to the antenna units one by one, and each decoupling network comprises a closed loop structure and a first transmission line and a second transmission line which are connected to the closed loop structure; the closed-loop structure is provided with a first output port and a second output port, the first transmission line is used for being connected with the radio frequency chip, one end of the second transmission line is connected with the first output port, and the other end of the second transmission line is connected with the corresponding antenna unit; the decoupling transmission line is connected between the second output ports of the adjacent decoupling networks; the ground layer and the decoupling networks are overlapped at intervals, the ground layer is provided with a slot, and at least one part of the slot is overlapped with the closed loop structure.

The antenna device introduces the concept of a decoupling network below the antenna units, does not need to change the structure of the array antenna units, only needs to configure the length of a decoupling transmission line and the S parameter of a three-port network, can accurately define the coupling degree between the antenna units, can reduce the mutual coupling between the antenna units, expands the scanning angle and improves the scanning gain. Furthermore, the power dividing ratio of the directional power divider can be calculated according to the amplitude of the isolation degree before decoupling, the characteristic impedance of each branch of the power divider is determined according to a formula, and then the width of a transmission line corresponding to the characteristic impedance can be calculated, so that the power divider can be manufactured. Based on the method, the isolation of the multi-antenna system can be improved. In addition, the decoupling network of the application comprises a closed loop structure, the closed loop structure is provided with a first output port and a second output port, a slot is formed in the antenna floor, and at least one part of the slot is overlapped with the closed loop structure, so that the interference influence between the first output port and the second output port of the power divider can be reversed in equal amplitude and mutually offset, the first output port and the second output port can not influence each other any more, and the isolation degree between the two output ports of the power divider main body can be remarkably improved. In addition, an isolation resistor is not required to be arranged between the two output ports of the power divider main body, and insertion loss can be reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application;

fig. 2 is a schematic diagram illustrating a decoupling principle of an array antenna according to an embodiment of the present application;

fig. 3 is a schematic structural diagram of an array antenna according to an embodiment of the present application;

fig. 4 is a schematic flow chart of a decoupling method for an array antenna according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of an electronic device according to an embodiment of the present application;

fig. 6 is a bottom view of the antenna device of the embodiment of the present application;

fig. 7 is a schematic diagram of a layered structure of two antenna elements of an antenna device according to an embodiment of the present application;

fig. 8 is a schematic view of an antenna arrangement according to another embodiment of the present application;

fig. 9 is a top view of an antenna device according to yet another embodiment of the present application;

fig. 10 is a front view of two antenna units of fig. 9, in which the substrate of the antenna device is omitted;

fig. 11 is a schematic perspective view of one of the antenna units in fig. 9, in which the substrate of the antenna device is omitted;

figure 12 shows an isolation contrast curve connecting the front and rear antenna elements of the decoupling network;

figure 13 shows a reflection parameter curve for an isolated antenna element before decoupling;

figure 14 shows a reflection parameter curve for the antenna element after decoupling;

figure 15 shows a comparison curve of the gain sweep of the antenna arrangement before and after connection of the decoupling network with the beam swept to 0 °;

figure 16 shows a comparison curve of the gain sweep of the antenna arrangement before and after connection of the decoupling network, with the beam swept to 45 °;

figure 17 shows a comparison curve of the gain sweep of the antenna arrangement before and after connection of the decoupling network, with the beam swept to 50 °;

figure 18 shows a decoupled network transmission coefficient curve; and

figure 19 shows the reflection parameters of the decoupling network.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the application. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The array antenna, especially the small-distance array antenna, has the problem of strong mutual coupling. Mutual coupling between antenna elements greatly affects the matching characteristics and spatial radiation characteristics of the antenna elements and the array thereof, and is expressed in the following points.

(1) Directional diagram: the distribution of the currents on the antennas is changed under mutual coupling, resulting in that part of the radiated energy is further coupled to other antenna elements, wherein a part of the coupled energy is absorbed by the terminating load and consumed, and another part of the energy is radiated again. Therefore, the pattern of the antenna may be distorted. The termination load is a parameter equivalent to the rear end of the antenna feed source; when drawing an equivalent circuit, the entire back end of the antenna feed may be replaced with a resistor and may be referred to as a terminating load.

(2) Input impedance: due to the mutual coupling, the input impedance of the antenna elements in the array changes and is different from the input impedance of the antenna elements in an isolated environment, so that the matching condition of the antenna elements in each array is different and the matching characteristic is affected.

(3) Gain: there are heat loss and reflection loss caused by impedance mismatch in the antenna unit, so that the radiation power of the antenna is smaller than the transmission power, and the reflection coefficient is changed under the effect of mutual coupling, so that the gain of the antenna is affected.

In the related art, in order to solve the influence of the mutual coupling effect on the characteristics of the directional pattern, the input impedance, the gain, and the like of the antenna unit, the following five methods are generally adopted: a Defected Ground Structure (DGS-Defected Ground Structure) Decoupling method, a neutral Line (NLT-neutral Line technology) Decoupling method, a Band-stop filtering Decoupling method, an Electromagnetic Band Gap (EBG) Decoupling method, and a Metamaterial Decoupling Method (MDT).

However, the above methods are all directed to the research of the method for eliminating the coupling between the antenna units, and the coupling effect between the antennas cannot be precisely defined and controlled.

The application provides an electronic device, an array antenna of the electronic device can self-define the coupling effect between antennas, and control of a radiation pattern of an antenna unit is achieved through the design of the coupling effect, for example, the scanning angle is widened, the scanning gain is improved, and a scanning blind area is eliminated.

The electronic device may be a terminal device such as a mobile phone, a tablet computer, a PDA (Personal Digital Assistant), a Point of Sales (POS), a vehicle-mounted computer, and a Customer Premise Equipment (CPE). The present application is described below with a mobile phone as an example.

As shown in fig. 1, the handset 100 may include: RF (Radio Frequency) circuitry 101, memory 102, a Central Processing Unit (CPU) 103, peripheral interfaces 104, audio circuitry 105, speakers 106, a power management chip 107, an input/output (I/O) subsystem 108, a touch screen 109, other input/control devices 110, and an external port 111, which communicate via one or more communication buses or signal lines 112.

It should be understood that the illustrated handset is merely one example of an electronic device and that the handset 100 may have more or fewer components than shown in the figures, may combine two or more components, or may have a different configuration of components. The various components shown in the figures may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.

The following describes each component of the mobile phone in detail with reference to fig. 1:

the RF circuit 101 is mainly used to establish communication between the mobile phone and the wireless network (i.e., network side), and implement data reception and transmission between the mobile phone and the wireless network. Such as sending and receiving short messages, e-mails, etc. Specifically, the RF circuit 101 receives and transmits RF signals, which are also referred to as electromagnetic signals, and the RF circuit 101 converts electrical signals into electromagnetic signals or vice versa and communicates with a communication network and other devices through the electromagnetic signals. The RF circuitry 101 may include known circuitry for performing these functions including, but not limited to, an antenna system with an antenna array, an RF transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a CODEC (CODEC) chipset, a Subscriber Identity Module (SIM), and so forth.

The memory 102 may be accessed by the CPU103, the peripheral interface 104, and the like, and the memory 102 may include high speed random access memory and may also include non-volatile memory, such as one or more magnetic disk storage devices, flash memory devices, or other volatile solid state storage devices.

The central processing unit 103 executes various functional applications and data processing of the electronic device by executing software programs and modules stored in the memory 102.

Peripheral interface 104 may connect input and output peripherals of the device to CPU103 and memory 102.

The I/O subsystem 108 may connect input and output peripherals on the device, such as a touch screen 109 and other input/control devices 110, to the peripheral interface 104. I/O subsystem 108 may include a display controller 1081 and one or more input controllers 1082 for controlling other input/control devices 110. Where one or more input controllers 1082 receive electrical signals from or transmit electrical signals to other input/control devices 110, the other input/control devices 110 may include physical buttons (push buttons, rocker buttons, etc.), dials, slide switches, joysticks, click wheels. It is worth noting that the input controller 1082 may be connected with any one of the following: a keyboard, an infrared port, a USB interface, and a pointing device such as a mouse.

The touch screen 109 is an input interface and an output interface between the user terminal and the user, and displays visual output to the user, which may include graphics, text, icons, video, and the like.

The display controller 1081 in the I/O subsystem 108 receives electrical signals from the touch screen 109 or sends electrical signals to the touch screen 109. The touch screen 109 detects a contact on the touch screen, and the display controller 1081 converts the detected contact into an interaction with a user interface object displayed on the touch screen 109, that is, implements a human-computer interaction, and the user interface object displayed on the touch screen 109 may be an icon for running a game, an icon networked to a corresponding network, or the like. It is worth mentioning that the device may also comprise a light mouse, which is a touch sensitive surface that does not show visual output, or an extension of the touch sensitive surface formed by the touch screen.

The audio circuit 105 is primarily used to receive audio data from the peripheral interface 104, convert the audio data to an electrical signal, and send the electrical signal to the speaker 106.

The speaker 106 is used to convert voice signals received by the handset 100 from the wireless network through the RF circuit 101 into sound and play the sound to the user.

The power management chip 107 is used for supplying power and managing power to the hardware connected to the CPU103, the I/O subsystem 108, and the peripheral interface 104.

The following is directed to an array antenna in an antenna system of the RF circuitry 101 of the electronic device. The array antenna generally includes a plurality of closely arranged antenna elements, and each antenna element is connected to a feed via a matching network in at least two adjacent antenna elements. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specifically limited otherwise.

The present embodiment describes the present application by taking two

adjacent antenna units

10 and 20 as an example, wherein the antenna unit 10 may be referred to as a first antenna unit 10, and the antenna unit 20 may be referred to as a second antenna unit 20. As shown in fig. 2, the antenna element 10 and the antenna element 20 are adjacent. The radiation characteristics of the antenna element 10 and the antenna element 20 may be the same or different. The antenna unit 10 can receive an excitation current from a feed source (radio frequency transceiver) of the electronic device, and after amplification, filtering, matching and tuning, the antenna unit 10 is excited to resonate at a corresponding frequency, so that an electromagnetic wave signal with the corresponding frequency is generated, and the electromagnetic wave signal with the same frequency as a free space is coupled to realize signal transmission; the antenna unit 10 may also couple electromagnetic wave signals with the same frequency from free space under the excitation of the excitation signal, so as to form an induced current on the antenna unit 10, and the induced current is filtered and amplified and then enters the rf transceiver.

The array antenna also includes a decoupling structure. Wherein the decoupling structure comprises a decoupling network and a decoupling transmission line connected to the decoupling network. Specifically, the decoupling networks corresponding to the two

adjacent antenna units

10 and 20 are connected to each other, where the antenna unit 10 corresponds to the first decoupling network 30 and the antenna unit 20 corresponds to the second decoupling network 30'. The first and second decoupling networks 30, 30' are each three-port networks. The first decoupling network 30 has an input port (a) to which the feed is connected₁,b₁) An output port (a) connected to the antenna unit 10₂,b₂) And a decoupling port (a) for connecting a second decoupling network 30₃,b₃). A second decoupling network 30 ' has an input port (a ') to which a feed is connected '₁,b’₁) And an output port (a ') connected to the antenna unit 20'₂,b’₂) And a decoupling port (a ') for connecting the first decoupling network 30'₃,b’₃). Wherein, a₁、a₂、a₃、a’₁、a’₂And a'₃Is the amplitude of the incident voltage wave, b₁、b₂、b₃、b’₁、b’₂And b'₃Is the reflected voltage wave amplitude. It should be noted that the "input port" and the "output port" in the embodiment of the present application are named only from the perspective of the antenna unit 10 transmitting signals. It is understood that the antenna unit 10 can also receive signals, and in this case, the "output port" can be used as an input port, and the "input port" can be used as an output port, that is, the names of the "input port" and the "output port" in this application are not limited to the attributes of the ports. Length d in fig. 2₁Forms the output port (a)₂,b₂) And has an impedance Z₂. Length d₂Forming the output port (a'₂,b’₂) And has an impedance Z₂. Wherein d is₁And d₂May be equal. Length d₅Is connected to a decoupling port (a) of the first decoupling network 30₃,b₃) Port (a ') decoupled from second decoupling network 30'₃,b’₃) And has an impedance Z₃. Wherein the first decoupling network 30 forms a power divider with the decoupling transmission line to be coupled from the input port (a) of the first decoupling network 30₁,b₁) The input power is distributed to the first antenna element 10 and the decoupled transmission line according to the power division ratio of the power divider. The second decoupling network 30 ' forms a power divider with the decoupled transmission line to be coupled from the input port (a ') of the second decoupling network 30 '₁,b’₁) The incoming power is distributed to the second antenna element 30 and the decoupling transmission line 33 in the preset ratio so as to cancel the mutual coupling between the two

antenna elements

10, 20.

It should be noted that the length d in FIG. 2 is₁Also shows an impedance Z on one side of the transmission line₂The two transmission lines correspond to the same wire in real object; likewise, length d₂Transmission line of length d₅The decoupled transmission line of (a) should also be understood as such.

As shown in fig. 3, it is a schematic diagram of a decoupling structure for an array antenna according to an embodiment of the present application, wherein at least a first decoupling network 30, a second decoupling network 30' and a decoupling transmission line 33 connected therebetween may constitute the decoupling structure for an array antenna according to the present application. In addition, the decoupling structure and the array antenna connected thereto may also form the antenna device of the present application.

The following description specifically refers to a first decoupling network 30 corresponding to the antenna unit 10 and a second decoupling network 30 'corresponding to the antenna unit 20 in fig. 3 as examples, and it is understood that the second decoupling network 30' may be the same as the first decoupling network 30.

In particular, the first decoupling network 30 is a three-port network. In some embodiments, the three-port network includes a closed loop structure 34 and first and

second transmission lines

31, 32 connected to the closed loop structure 34. The closed loop structure 34 is provided with a first output port and a second output port, the first transmission line 31 is used for connecting with the feed source 40, one end of the second transmission line 32 is connected with the first output port, and the other end is connected with the corresponding antenna unit 10.

The closed-loop structure 34 may be a power divider, and includes a first branch 341, a second branch 342, and a microstrip connection line 343. The first end of the first branch 341 and the first end of the second branch 342 are connected to the same end of the first transmission line 31, and the second end of the first branch 341 forms a first output port. The second end of the second branch 342 forms a second output port. Wherein the second output port is a decoupled port of the first decoupling network 30. The lengths of the first branch 341 and the second branch 342 are equal, or the length difference between the first branch 341 and the second branch 342 is equal to the wavelength, so that the phases of the two output ports of the power splitter can be kept the same. The microstrip connection line 343 is connected between the first output port and the second output port to form a closed structure, so that the junction of the two signals is in equal amplitude and opposite phase, and superposition cancellation is realized, that is, the path difference of the two signals is one wavelength at the junction of the two signals. The first branch 341, the second branch 342, and the microstrip connection line 343 are sequentially connected end to form a closed shape, and the power divider in the closed shape is matched with a slot formed in the ground plane of the antenna unit 10, so that the interference influence between the first output port and the second output port of the closed structure 34 is in equal amplitude and opposite direction, and further mutually offset, thereby improving the isolation between the first output port and the second output port of the closed structure 34. In some embodiments, the first branch 341, the second branch 342, and the microstrip line 343 are arc-shaped, and further form a circular ring. In other embodiments, the first branch 341, the second branch 342, and the microstrip connection line 343 may also enclose an elliptical ring shape, or a polygon shape. In some embodiments, the closed loop structure 34 may be in an axisymmetric pattern.

A first end of the first transmission line 31 is connected to first ends of the first and

second branches

341, 342 and a second end of the first transmission line 31 forms an input port of the first decoupling network 30. A first end of the second transmission line 32 is connected to a second end of the first branch 341 (i.e. a first output port of the closed loop structure 34), the second end of the second transmission line 32 forming an output port of the first decoupling network 30. It is noted that the first and second ends of a transmission line as described herein refer to the two opposite ends of the transmission line.

The second decoupling network 30 ' may also be a three-port network including a closed loop structure 34 ' and first and second transmission lines 31 ', 32 ' connected to the closed loop structure 34 '.

The closed loop structure 34 'may also be a power divider, comprising a first branch 341', a second branch 342 'and a microstrip connection line 343'. The first end of the first branch 341 'and the first end of the second branch 342' are connected to the same end of the first transmission line 31 ', and the second end of the first branch 341' forms a first output port. The second end of the second branch 342' forms a second output port. The microstrip connection line 343' is connected between the first output port and the second output port to form a closed structure, so that the junction of the two signals has equal amplitude and opposite phase, and superposition cancellation is realized, i.e. the path difference of the two signals at the junction of the two signals is one time of wavelength.

A first end of the first transmission line 31 ' is connected to first ends of the first and second branches 341 ' and 342 ', and a second end of the first transmission line 31 ' forms an input port of the second decoupling network 30 '. A first end of the second transmission line 32 ' is connected to a second end of the first branch 341 ' (i.e. a first output port of the closed loop structure 34 '), the second end of the second transmission line 32 ' forming an output port of the second decoupling network 30 '. It is noted that the first and second ends of a transmission line as described herein refer to the two opposite ends of the transmission line.

A first end of the decoupling transmission line 33 is connected to a decoupling port (i.e., a second output port) of the first decoupling network 30 and a second end of the decoupling transmission line 33 is connected to a decoupling port (i.e., a second output port) of the second decoupling network 30 ', thereby connecting the first and second decoupling networks 30, 30' together.

The terms "first", "second" and "third" in this application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any indication of the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature.

The current profile of the first decoupling network 30 is described below: current flows from the feed 40 into the first transmission line 31 from a first end of the first transmission line 31 (i.e. the input port of the first decoupling network 30), and is split into two flows at a second end of the first transmission line 31 to the first branch 341 and the second branch 342 according to the power division ratio. The current entering the first branch 341 flows from the first output port of the closed structure 34 into the second transmission line 32 and enters the antenna element 10 from the second end of the second transmission line 32 (i.e. the output port of the first decoupling network 30) via the feed port of the antenna element 10. The current entering the second branch 342 flows from the second output port of the enclosed structure 34 into the decoupling transmission line 33, thereby achieving the decoupling effect. The above embodiments are only described in terms of power distribution performed by the power divider, and it can be understood that the power divider of the above embodiments may be used in terms of power synthesis, and the current trend thereof is not described herein again.

The decoupling transmission line 33 of the embodiment of the present application is used to transmit signals to cancel mutual coupling between the two

antenna elements

10, 20. Wherein the degree of coupling between the two

antenna elements

10, 20 can be determined by the scattering parameters (i.e. S-parameters) of the first and second decoupling networks 30, 30' and the length of the decoupling transmission line 33. For example, if the coupling degree between the two

antenna units

10 and 20 is required to reach the preset coupling degree D, the S-parameter of the three-port network and the length of the decoupling transmission line 33 may be configured such that the coupling degree between the

antenna units

10 and 20 satisfies the preset coupling degree D.

It is readily apparent that when the first decoupling network 30 and the second decoupling network 30' adopt the same structure, their S parameters are also the same. Thus, in case the first and second decoupling networks 30, 30 'are identical, the relation between the degree of coupling between the two

antenna elements

10, 20 and the S-parameter of the three-port network (first or second decoupling network 30, 30') and the length of the decoupled transmission line can be obtained by:

the [ S ] matrix of the decoupling network is:

wherein S is₁₁、S₂₂、S₃₃Is the reflection coefficient of three ports when a three-port network exists alone; s₁₂Is the power fed from the input port directly to the output port; s₁₃Is the power fed from the input port to the decoupled port; s₂₃Is the power fed from the decoupled port to the output port.

Can be combined with S₁₁、S₂₂、S₃₃And S₂₃Designed to be 0, the S parameter matrix is:

at reference plane II in FIG. 2, a decoupled port of a three-port network is connected by a length d₅The decoupling transmission line of (1) has an S parameter relational expression of a six-port network consisting of two three-port networks as follows:

where k is the wave number, e is a natural constant, and j is an expression symbol of an imaginary number.

Writing the matrix in equation (3) into a block matrix form:

rewriting equation (5) into the form of a equation set:

formula (4) is abbreviated:

[a₂]＝[Γ]·[b₂] (7)

the formula (7) may be substituted for the formula (6):

from the second expression in the formula (8):

[b₂]＝{E-[S₂₂][Γ]}^-1[S₂₁][a₁] (9)

wherein E represents an identity matrix.

The formula (9) is substituted for the formula (8) to obtain:

[b₁]＝[S₁₁][a₁]+[S₁₂][Γ]{E-[S₂₂][Γ]}^-1[S₂₁][a₁] (10)

as can be seen from equation (10), the S parameter matrix of the four-port network (1, 2, 1 ', 2') formed by connecting two three-port networks through a decoupling transmission line is:

S_Four-port＝[S₁₁]+[S₁₂][Γ]{E-[S₂₂][Γ]}^-1[S₂₁] (11)

it is noted that, the four ports of the four-port network here refer to the four outward ports (a) formed by two three-port networks after being connected₁,b₁)、(a₂,b₂)、(a’₁,b’₁) And (a'₂,b’₂)。

Substituting the block matrixes planned by the formulas (3) and (5) into a formula (11), so as to obtain a new S parameter matrix of the four-port network, wherein the new S parameter matrix is as follows:

the port order of the four-port network is adjusted to 1 → 1 '→ 2 → 2', and equation (12) becomes:

the formula (13) is rewritten into the form of a composition block matrix:

setting an S parameter matrix of a binary antenna array formed by the two antenna units as follows:

(iii) in formula (15), S'₁₂Is the strength of the initial isolation of the binary antenna, i.e., the strength of the isolation between two

adjacent antenna elements

10 and 20 when no decoupling network is connected; s'₁₁、S’₂₁And S'₂₂Respectively the input reflection coefficient, the forward transmission coefficient (gain) and the output reflection coefficient when no decoupling network is connected between two

adjacent antenna elements

10 and 20.

After the two three-port networks are connected together through a decoupling transmission line, the formed four-port network is connected with the two

antenna units

10 and 20 to form a two-port (1, 1') network. The S parameter matrix of the two-port network is:

[S]＝[S₁₁]+[S₁₂][S_array]{E-[S₂₂][S_array]}^-1[S₂₁] (16)

it is noted that the two ports of the two-port network herein refer to the two ports (a) for connection with the feed source which are left after the connection between the two three-port networks and after the two

antenna units

10 and 20 are connected, respectively (a)₁,b₁) And (a'₁,b’₁)。

By substituting the block matrices defined by equations (13) and (14) into equation (16), we can obtain:

as can be seen from the formula (17),

wherein, S'₁₂Is the strength of the initial isolation, i.e., the strength of the isolation when the first and second decoupling networks 30 and 30' are not connected between two

adjacent antenna units

10 and 20.

It can be seen that the length d of the transmission line 33 is designed to be decoupled₅And the S parameter of the three-port network, namely, the coupling degree among the antennas can be accurately defined. That is, when the required coupling degree is preset, the above formula can be expressed as:

therefore, the length d5 of the decoupling transmission line 33 and the S-parameter of the three-port network may be configured such that the degree of coupling between the

antenna elements

10, 20 satisfies a preset degree of coupling.

In some embodiments, the first decoupling network 30 and the decoupling transmission line 33 may form a power divider. The second decoupling network 30' and the decoupling transmission line 33 may also form a power divider. In this case, the degree of coupling between the two

antenna elements

10, 20 can be zeroed out by configuring the length of the decoupling transmission line 33 and the power dividing ratio of the power divider.

The length of the decoupling transmission line 33 and the power division ratio of the power divider may be determined by the initial isolation between the two

antenna elements

10, 20, where the initial isolation is the isolation between the two antenna elements when no decoupling network is connected. That is, in some embodiments, the power ratio between the two

antenna elements

10, 20 may be configured according to the initial isolation and the length of the decoupling transmission line 33 to null the coupling between the two

antenna elements

10, 20.

Specifically, the power divider may have a power ratio that is determined by the strength of the initial isolation (i.e., S ') between the two antenna elements'₁₂) To be determined. The length of the decoupled transmission line 33 may then be taken through the phase (phi ') of the initial isolation between the two antenna elements 10, 20'₁₂) To be determined.

For example, when the decoupling network is required to completely cancel the mutual coupling between the two

antenna units

10 and 20, and the predetermined coupling degree is set to 0, then

From the formula (18):

wherein the content of the first and second substances,

is the power dividing ratio of the power divider, therefore, the S parameter of the decoupling network can be determined according to the power dividing ratio.

From the formula (19), if

And phi is₁₂＝φ₁₃Then, then

As can be seen from this, when the power division ratio of the power divider is set so as to satisfy the relationship of expression (21) with respect to the strength of the initial isolation between the two

antenna elements

10 and 20, and the length of the decoupling transmission line 33 is set so as to satisfy the relationship of expression (21) with respect to the phase of the initial isolation between the two

antenna elements

10 and 20, the degree of coupling between the two

antenna elements

10 and 20 can be set to zero.

Specifically, strength S 'of initial isolation'₁₂And phase phi'₁₂Since the relationship between the wave number k and the wavelength λ is known, d can be obtained by expressing the wave number k by the wavelength λ and substituting the formula (21)₅The calculation formula of (2):

therefore, the power division ratio of the power divider and the length d of the decoupling transmission line 33 are calculated₅Then, a power divider having the power dividing ratio and a decoupled transmission line 33 having the length can be designed to realize the degree of coupling nulling.

In some embodiments, the power divider has a power ratio related to the characteristic impedance of the first transmission line 31, the first branch 341 and the second branch 342. As can be seen from the above embodiments, the power division ratio of the power divider can be known according to the strength of the initial isolation, and thus, the characteristic impedance of the first branch 341 and the second branch 342 can be determined according to the known power division ratio and the characteristic impedance of the first transmission line 31. Therefore, the characteristic impedance of both the first branch 341 and the second branch 342 can be determined according to the characteristic impedance of the first transmission line 31 and the strength of the initial isolation.

In particular, the characteristic impedance Z of the first branch 341₂Characteristic impedance Z with respect to first transmission line 31₁And a power dividing ratio (strength of initial isolation S'₁₂) The following relationship is satisfied:

Z₂＝(1+|S’₁₂|)ⅹZ₁ (23)

characteristic impedance Z of the second branch 342₃Characteristic impedance Z with respect to first transmission line 31₁And a work fraction ratio (i.e., strength of initial isolation S'₁₂) The following relationship is satisfied:

therefore, as can be seen from the above description, the required power division ratio of the power divider can be obtained by presetting the coupling degree, and then the required characteristic impedance Z of the first branch 341 can be obtained according to the power division ratio₂And the characteristic impedance Z of the second branch 342₃Thereby configuring the first 341 and second 342 branch of the decoupling network such that the characteristic impedance of the first 341 branch meets the required characteristic impedance Z₂And the characteristic impedance of the second branch 342 satisfies the required characteristic impedance Z₃。

In some embodiments, the characteristic impedance of the transmission line may be satisfied by configuring the line width of the transmission line, i.e., the line width of the first branch 341 is determined according to the characteristic impedance of the first branch 341. The line width of the second branch 342 is determined according to the characteristic impedance of the second branch 342. For example, the characteristic impedance Z of the first branch 341 is obtained in accordance with the above-described relational expression₂Thereafter, the line width of the first branch 341 may be configured such that its characteristic impedance satisfies the above-mentioned characteristic impedance Z₂. For example, after determining the required thickness of the first branch 341, the relative dielectric constant of the PCB board, and the thickness of the dielectric layer, the relationship between the characteristic impedance and the line width and the required characteristic impedance Z are determined₂The line width of the first branch 341 can be calculated. Therefore, the line width of the first branch 341 is configured according to the calculation resultThereby obtaining a characteristic impedance Z having the above-mentioned characteristic impedance₂The first branch 341.

Similarly, the second branch 342 may be configured to satisfy the required characteristic impedance Z by configuring the line width of the second branch 342₃. The line width of the second branch 342 can be determined according to the relationship between the characteristic impedance and the line width and the required characteristic impedance Z₃To calculate. Therefore, the line width of the second branch 342 is configured according to the calculation result, thereby obtaining the impedance Z having the above-described characteristic impedance₃And a second branch 342.

In some embodiments, the input impedance of the feed ports of the

antenna elements

10, 20 is 50 Ω matched, and thus the second transmission line 32 is configured as a 3-segment 1/4 λ length transmission line, i.e., the length of the second transmission line 32 is configured 3/4 λ to impedance match it to 50 Ω.

In combination with the decoupling structure, the present application also proposes a decoupling method for an antenna device, which may be the antenna device of any of the above embodiments. Fig. 7 is a flowchart illustrating a decoupling method for an antenna device according to an embodiment of the present application.

As shown in fig. 4, the decoupling method may mainly include the following operations S101-S105.

Operation S101: obtaining the strength of the initial isolation between the first antenna unit and the second antenna unit; the initial isolation is the isolation when the first antenna unit and the second antenna unit are not connected with the first decoupling network and the second decoupling network.

Operation S102: and determining the power dividing ratio of the power divider according to the strength of the initial isolation.

Operation S103: the power fed into the first decoupling network is distributed to the first antenna element and the decoupling transmission line according to a power division ratio.

In some embodiments, the decoupling method further comprises the operations of: obtaining the phase of the initial isolation; the length of the decoupled transmission line is determined according to the phase of the initial isolation.

In some embodiments, the degree of coupling between the first antenna element and the second antenna element is determined based on a length of the decoupled transmission line and scattering parameters of the first three-port network and the second three-port network.

In some embodiments, the degree of coupling between the first antenna element and the second antenna element is determined according to the following relationship:

degree of coupling; wherein, S'₁₂The strength of the initial isolation between the first antenna unit and the second antenna unit is shown, and the initial isolation is the isolation when the first antenna unit and the second antenna unit are not connected with the first three-port network and the second three-port network; s₁₂And S₁₃Is a scattering parameter of the first three-port network; d₅Length of the transmission line for decoupling; k is the wave number, e is the natural constant, and j is the notation of the imaginary number.

In some embodiments, the length of the decoupling transmission line is set according to the phase of the initial isolation of the first antenna element and the second antenna element.

In some embodiments, the power divider ratio of the power divider and the length of the decoupled transmission line are determined according to the aforementioned relationship (21). In some embodiments, the characteristic impedance of the first branch and the second branch is determined according to the characteristic impedance of the first transmission line and the strength of the initial isolation.

In some embodiments, the characteristic impedance of the first branch is determined according to the aforementioned relation (23).

In some embodiments, the characteristic impedance of the second branch is determined according to the aforementioned relation (24).

In some embodiments, the line width of the first branch is calculated from the characteristic impedance of the first branch and the line width of the second branch is calculated from the characteristic impedance of the second branch.

In some embodiments, the length of the decoupled transmission line is determined according to the aforementioned relationship (22).

It is readily apparent that the same matters described in the decoupling principle section of the present application are applicable to the decoupling method and will not be described in detail here.

In some embodiments, the electronic device of the present application may be a cell phone 100a as shown in fig. 5, the cell phone 100a including, but not limited to, the following structures: a housing 41 and a display screen assembly 50 coupled to the housing 41. Wherein, an accommodating space is formed between the housing 41 and the display screen assembly 50. Other electronic components of the mobile phone, such as a main board, a battery, and the antenna device 60, are disposed in the accommodating space.

Specifically, the housing 41 may be made of plastic, glass, ceramic, fiber composite, metal (e.g., stainless steel, aluminum, etc.), or other suitable material. The housing 41 shown in fig. 5 is generally rectangular with rounded corners. Of course, the housing 41 may have other shapes, such as circular, oblong, elliptical, and the like.

The display panel assembly 50 includes a display panel cover 51 and a display module 52. The display module 52 is attached to the inner surface of the display cover 51. The housing 41 is connected to a display cover 51 of the display assembly 50. The display screen cover plate 51 may be made of glass; the display module 52 may be an OLED flexible display structure, and may specifically include a substrate, a display Panel (Panel), an auxiliary material layer, and the like, and a polarizing film may be further interposed between the display module 52 and the display Panel cover plate 51, and a detailed stacked structure of the display module 52 is not limited herein.

The antenna device 60 may be completely housed inside the housing 41, or may be embedded in the housing 41, and a part of the antenna device 60 may be exposed on the outer surface of the housing 41.

In some embodiments, the antenna assembly 60 may include a plurality of spaced apart antenna elements, a plurality of decoupling networks, and a decoupling transmission line. The decoupling transmission lines are connected between adjacent decoupling networks. The decoupling network may be the decoupling network of any of the above embodiments.

In some embodiments, the plurality of antenna elements of the antenna arrangement 60 may be a quaternary linear array as shown in fig. 6, i.e. having four linearly arranged

antenna elements

10a, 20a, 10b and 20 b.

Specifically, referring to fig. 7, the antenna device 60 includes a first substrate 61, a second substrate 62, a third substrate 63, and a radio frequency chip 64, which are sequentially stacked, and a plurality of antenna units (fig. 8 only shows 2

antenna units

10a and 20a) formed on the first substrate 61, a plurality of metal layers 661-. The multiple feeders, the multiple decoupling networks and the multiple antenna units are in one-to-one correspondence. The present embodiment is described with an antenna element 10a, a first decoupling network 30 and corresponding feed lines. The feed line is used to connect the corresponding antenna element 10a, decoupling network 30 and radio frequency chip 64. The decoupling transmission line 33a is used to connect the first and second decoupling networks 30, 30' of the

adjacent antenna units

10a, 20a together to cancel the coupling between the

antenna units

10a, 20 a. It is understood that the antenna device 60 may also include other signal transmission lines.

The

antenna elements

10a, 20a are used for transceiving radio frequency signals. As shown in fig. 7, the two

antenna elements

10a, 20a are spaced apart from each other. The

antenna units

10a, 20a are double-layered patch antennas, and include

surface radiation pieces

11a, 21a and

inner radiation pieces

12a, 22a that are isolated from each other and correspond to each other one to one.

The first substrate 61 includes a first outer surface 611 and a first inner surface 612 disposed opposite to each other. The

surface radiation sheets

11a and 21a are disposed on the first outer surface 611, and the

inner radiation sheets

12a and 22a are disposed on the first inner surface 612. The

inner radiation sheets

12a and 22a are isolated from the

surface radiation sheets

11a and 21a by the first substrate 61, so that the

surface radiation sheets

11a and 21a and the

inner radiation sheets

12a and 22a are spaced by a certain distance, thereby meeting the performance requirement of the antenna frequency band. The

surface radiation pieces

11a and 21a and the

inner radiation pieces

12a and 22a are at least partially overlapped in a vertical projection on the first substrate 61.

The first substrate 61 may be made of a thermosetting resin such as an epoxy resin, a thermoplastic resin such as a polyimide resin, an insulating material (e.g., prepreg, ABF (Ajinomoto fabric-up Film), a photo dielectric (PID), etc.) including a reinforcing material such as a glass fiber (or glass cloth ) and/or an inorganic filler, and a thermosetting resin and a thermoplastic resin. However, the material of the first substrate 61 is not limited thereto. That is, a glass plate or a ceramic plate may also be used as the material of the first substrate 61. Alternatively, a Liquid Crystal Polymer (LCP) having a low dielectric loss may also be used as the material of the first substrate 61 to reduce signal loss.

In some embodiments, the first substrate 61 may be a prepreg, and as shown in fig. 7, the first substrate 61 includes three layers of prepregs stacked. In the three prepregs of the first substrate 61,

metal layers

662 and 663 are respectively provided between adjacent prepregs. The first substrate 61 is further provided with a metal layer 661 on the first outer surface, wherein the metal layer 661 and the

surface radiation pieces

11a and 21a are located on the same layer and are insulated from each other. The first inner surface 612 of the first substrate 61 is provided with a metal layer 664, and the metal layer 664 and the

inner radiation sheets

12a and 22a are located at the same layer and insulated from each other. The metal layers 661, 662, 663 and 664 may be made of conductive materials such as metallic copper, aluminum, silver, tin, gold, nickel, lead, titanium or their alloys. In this embodiment, the metal layers 661, 662, 663 and 664 are all copper layers.

The metal layer 661 is provided to reduce a difference between a copper plating ratio of the first outer surface 611 of the first substrate 61 and a copper plating ratio of the surface of the other prepreg of the first substrate 61, and the difference between the copper plating ratios can reduce the generation of bubbles during the manufacturing process of the first substrate 61, thereby improving the manufacturing yield of the first substrate 61. Similarly, the metal layer 664 is also disposed to reduce the difference between the copper spreading rate of the first inner surface 612 of the first substrate 61 and the copper spreading rate of the surfaces of the other prepregs of the first substrate 61, so as to reduce the generation of bubbles during the manufacturing process of the first substrate 61, thereby improving the manufacturing yield of the first substrate 61.

The first substrate 61 is also provided with ground vias 613 through the first inner surface 612 and the first outer surface 611 to connect the different metal layers 661,662, 663 and 664 to each other and further to the ground layer 665. Specifically, the conductive material may completely fill the ground via 613, or the conductive material may form a conductive layer along the wall of the ground via 613. The conductive material may be copper, aluminum, silver, tin, gold, nickel, lead, titanium, or an alloy thereof. The ground via 613 may have a cylindrical shape, an hourglass shape, a conical shape, or the like.

The second substrate 62 includes a first side surface 621 and a second side surface 622, wherein the first side surface 621 is overlapped on the first inner surface 612 of the first substrate 61. The second substrate 62 may be a core layer of a PCB board and is made of polyimide, polyethylene terephthalate, polyethylene naphthalate, or the like. The second substrate 62 is provided with a ground via 623 and a feeder via 624 penetrating the first and second side surfaces 621 and 622.

The ground layer 665 is interposed between the second substrate 62 and the third substrate 63. The ground layer 665 is provided with a feed line via 665 a. Referring to fig. 6, the ground layer 665 further defines a slot 665b, and at least a portion of the slot 665b overlaps the closed-loop structure 34. In some embodiments, the slots 665b can enclose an axisymmetric pattern. The axis of symmetry of slot 665b overlaps the axis of symmetry of closed-loop structure 34. In some embodiments, the slot 665b can enclose a closed shape. In other embodiments, the slot 665b can include a closed-loop slot 665d and a stripe slot 665c extending from the closed-loop slot 665d, at least a portion of the stripe slot 665c overlapping the closed-loop structure 34. At least a part of the strip-shaped groove 665c overlaps with the microstrip connection line 343, and the microstrip connection line 343 is symmetrically disposed with respect to the strip-shaped groove 665 c. The closed-loop structure 34 and the closed-loop groove 665d are symmetrical with respect to a line in which the strip-shaped groove 665c is located. The closed-loop groove 665d may have a closed shape such as a circular ring, an elliptical ring, a polygon, or a serpentine shape. Specifically, when the strip 665c is excited, the central plane of the strip 665c is opposite to an electric wall, the end of the strip 665c is a closed-loop groove 665d, and when a signal enters the closed-loop groove 665d from the strip 665c, the signal is divided into two paths of signals with equal size and opposite phases. At the position opposite to the stripe slot 665c on the other side of the closed-loop slot 665d, the two signals cancel each other out. In some embodiments, the length of the stripe slot 665c can be 1/4 λ, which is more advantageous for adjusting network matching characteristics.

The third substrate 63 includes a second outer surface 631 and a second inner surface 632 oppositely disposed. Second inner surface 632 of third substrate 63 is stacked on second side surface 622 of second substrate 62, and ground layer 665 is sandwiched between second side surface 622 and second inner surface 632.

The third substrate 63 may be formed of the same material as the first substrate 61. In some embodiments, the third substrate 63 may be a prepreg and have a multilayer structure. As shown in fig. 7, the third substrate 63 includes three layers of prepregs. In the three layers of prepregs of the third substrate 63,

metal layers

666 and 667 are provided between adjacent prepregs as a feeding network and a control line wiring layer, respectively. A metal layer 668 is disposed on the second outer surface 631 of the third substrate 63, and the metal layer 668 is soldered to the rf chip 64. The metal layers 666, 667, and 668 can be made of conductive material such as copper, aluminum, silver, tin, gold, nickel, lead, titanium, or their alloys. In this embodiment,

metal layers

666, 667, and 668 are all copper layers.

The third substrate 63 has a wiring via hole. The routing vias include ground vias 633 to connect the

different metal layers

666, 667, and 668 to each other and further to a ground layer 665. The routing vias also include a feed line via 634 through which a feed line passes, a signal via 635 through which a control line passes, and the like. Similar to the ground via 613 on the first substrate 61, the wiring via on the third substrate 63 may be completely filled with a conductive material, or a conductive layer may be formed on the wall of the via. The various wiring vias may be cylindrical, hourglass, or pyramidal in shape.

The rf chip 64 is disposed on a side of the third substrate 63 away from the first substrate 61, and corresponds to the feeds of the previous embodiments, such as the first feed 40 and the second feed 40'. When there are multiple feeds, the multiple feeds may be the same or different.

The feed lines include a first feed line 65 and a second feed line 67. The decoupling networks 30, 30' are connected between corresponding first and

second feeders

65, 67, respectively. One end of the first feed line 65 is disposed on the side of the third substrate 63 remote from the second substrate 62 to connect the radio frequency chip 64, and the other end extends into the third substrate 63, i.e., through the feed line via 634 of the third substrate 63 to connect to the decoupling network 30. A portion of the second feed line 67 is disposed within the third substrate 67 to connect the decoupling network 30 and another portion extends through the second substrate, i.e. through the feed line via 624 of the second substrate 62 to connect the corresponding antenna element 10 a. Therefore, the radio frequency chip 64, the first feeder 65, the decoupling network 30, the second feeder 67 and the antenna unit 10 are connected in sequence, and signal transmission between the antenna unit 10 and the radio frequency chip 64 is realized. The feed lines are insulated from the metal layers, such as

metal layers

666, 667, 668 and ground layer 665 of this embodiment.

In addition, other signal transmission lines, such as a control line 68 and a power line 69, are provided on the third substrate 63. As shown in fig. 7, the power supply line 69 is disposed on the second outer surface 631 of the third substrate 63 and is soldered on the rf chip 64. The control line 68 is disposed between the prepreg of the third substrate 63 close to the rf chip 64 and the adjacent prepreg, and passes through the signal via 635 on the prepreg to be connected to the rf chip 64.

Furthermore, the third substrate 63 is also used to carry a plurality of decoupling networks, which may be the decoupling networks of any of the previous embodiments, and the decoupling transmission line 33 a. The first decoupling network 30 is connected between the corresponding first antenna element 10a and the radio frequency chip 64. The second decoupling network 30' is connected between the corresponding second antenna element 20a and the rf chip 64. Both ends of the decoupling transmission line 33a are connected to decoupling ports of the first and

second decoupling networks

30a and 30 a', respectively. The first decoupling network 30 is a three-port network comprising a closed loop structure 34, a first transmission line 31a and a second transmission line 32a, and the coupling between the two

antenna elements

10a, 20a can be reduced after the decoupling transmission line 33a is connected between the two three-port networks. For example, after a signal transmitted from the rf chip 64 is input into the first transmission line 31a through the first feeding line 65, a part of the signal enters the second transmission line 32a through the first branch 341, and then is transmitted to the inner radiation patch 12a of the antenna unit 10a through the second feeding line 67, and another part of the signal enters the decoupling transmission line 33a through the second branch 342, and then is transmitted to the adjacent antenna unit 20a, so as to cancel the coupling between the two

antenna units

10a and 20 a.

In some embodiments, the strip-shaped groove 665c formed in the ground layer 665 extends to a position between the first output port and the second output port of the closed-loop structure 34, and the first output port and the second output port are symmetrical with respect to the strip-shaped groove 665 c. In addition, the microstrip connection line 343 is configured in a circular arc shape, and the microstrip connection line 343 is symmetrical with respect to the strip-shaped groove 665 c. Therefore, the interference influence between the first output port and the second output port of the power divider body 34 can be reversed in equal amplitude and mutually offset, and the first output port and the second output port can not influence each other any more, so that the isolation between the two output ports of the power divider body can be remarkably improved.

The degree of coupling between the two

antenna elements

10a, 20a can be defined by the scattering parameters of the decoupling network and the length of the decoupling transmission line 33 a. Specifically, as in the above-mentioned embodiment of the array antenna, the length d5 of the decoupling transmission line 33a of the decoupling network of the antenna device 60 of the present embodiment, and the S parameter and the preset coupling degree of the decoupling network satisfy the following relationship:

in some embodiments, the length of the decoupling transmission line 33a and the power division ratio of the power divider in the decoupling network are configured to null the degree of coupling between the two

antenna elements

10a, 20 a.

In some embodiments, the length of the decoupling transmission line 33a and the power division ratio of the power divider are configured according to the initial isolation between the two

antenna elements

10a, 20 a. Specifically, the power division ratio of the power divider is configured according to the strength of the initial isolation, and the length of the decoupling transmission line 33a is configured according to the phase of the initial isolation. For example, the relationships between the power dividing ratio of the power divider and the strength of the initial isolation, and between the length of the decoupling transmission line 33a and the phase of the initial isolation satisfy the aforementioned relationships (21) and (22).

In some embodiments, the power division ratio of the power divider may be specifically realized by configuring the characteristic impedance of the first branch 341 and the second branch 342. E.g. the characteristic impedance Z of the first branch 341₂Characteristic impedance Z with respect to the first transmission line 31a₁And a power dividing ratio (strength of initial isolation S'₁₂) Satisfies the above relation (23). Characteristic impedance Z of the second branch 342₃Characteristic of the first transmission line 31aSexual impedance Z₁And a work fraction ratio (i.e., strength of initial isolation S'₁₂) Satisfies the above relation (24).

As described in the above embodiments of the antenna array, the characteristic impedance of the transmission line can be made satisfactory by configuring the line width of the transmission line. For example, the line width of the first branch 341 is configured such that the first branch 341 satisfies the above-described required characteristic impedance Z₂. The line width of the second branch 342 is configured such that the second branch 342 satisfies the required characteristic impedance Z₃。

The first decoupling network 30 and the decoupling transmission line 33 may be disposed on a layer of the third substrate 63, for example, on a prepreg of the third substrate 63 near the rf chip 64 or on an intermediate prepreg. The first decoupling network 30 and the decoupling transmission line 33 shown in fig. 7 are disposed on a prepreg, which is located at the middle of the third substrate 63, that is, at the same layer as the metal layer 666. The first decoupling network 30 is spaced from the ground layer 665 by a portion of the third substrate 63 (i.e. the prepreg adjacent the second substrate). The closed loop structure 34 of the first decoupling network 30, the first transmission line 31a, the second transmission line 32a and the decoupling transmission line 33 all extend and are patterned on this layer. In some embodiments, the metal layer 666 can be formed on the layer with a length satisfying the desired length d₅The decoupled transmission line 33 a. It can be understood that the linear distance between the corresponding feed lines of the adjacent antenna units is less than d₅In this case, the decoupling transmission line 33a may be formed in a meandering pattern to satisfy the length requirement (as shown in fig. 6). In other embodiments, the decoupling transmission line 33a may also be in a curved pattern. The first and second decoupling networks 30, 30' of the present application are located at different layers from the surface and

inner radiating patches

11a, 21a, 12a, 22 a. As shown in fig. 7, the decoupling transmission line 33a is disposed below the

antenna elements

10a, 20a, e.g., within a third substrate 63. The first and second decoupling networks 30, 30' and the decoupling transmission line 33 connected between them shown in fig. 7 are located at the same layer as the metal layer 666, i.e. between the prepreg of the third substrate 63 closest to the ground layer 665 and its adjacent prepreg. It will be appreciated that in other embodiments, the first decoupling network 30 and the second decoupling networkThe two decoupling networks 30' and the decoupling transmission line 33 connected between them can also be in the same layer as the

metal layer

667 or 668.

The decoupling transmission line 33a may also be distributed on different layers, for example, a part of the decoupling transmission line 33a is distributed on the layer where the metal layer 666 is located, and another part is distributed on the layer where the metal layer 667 is located through the via; alternatively, a portion of the decoupled transmission line 33a is distributed on the layer of the metal layer 666, a portion is distributed on the layer of the metal layer 667 through a via, and another portion is distributed on the layer of the metal layer 668 through a via.

In some embodiments, the characteristic impedance may gradually change in a direction from the second branch 342 to an intermediate position of the decoupled transmission line 33 a. The change in the characteristic impedance of the transmission line can be realized by a change in the line width of the transmission line. In some embodiments, the line width gradually changes from the second branch 342 to an intermediate position of the decoupled transmission line 33 a. In some embodiments, the linewidth of the decoupling transmission line 33a varies stepwise from the second branch 342 to an intermediate position of the decoupling transmission line 33 a. For example, the decoupled transmission line 33a shown in fig. 6 includes a first segment 331a, a second segment 332a, and a third segment 333a connected in sequence, wherein each segment itself may be uniform in width. The first and

third sections

331a and 333a have the same width. The width of the second branch 342 is smaller than the width of the first section 331 a. The width of the first section 331a is smaller than the width of the second section 332 a. The width of the second branch 342 of the adjacent decoupling network is less than the width of the third segment 333 a. The width of the third segment 333a is smaller than the width of the second segment 332 a. Therefore, the characteristic small impedance changes stepwise from the second branch 342 to the first section 331a to the second section 332a, and from the second branch 342 to the third section 333a to the second section 332a, until the characteristic impedance of the second section 332a reaches 50 Ω. By means of a multi-stage impedance transformation, the appropriate characteristic impedance of the second branch 342 and the decoupled transmission line 33a enables full matching over a plurality of frequency points, increasing the number of matched nodes enables the frequency points at which matching occurs to increase, with a consequent increase in bandwidth. The characteristic impedance of the second branch 342 can be calculated according to the power dividing ratio of the power divider, such as the above relation (24), and the width thereof can be calculated from the characteristic impedance; the characteristic impedance of the second segment 332a is 50 Ω, and the width thereof can also be calculated from the characteristic impedance; the characteristic impedance of the first and

third segments

331a, 333a may then be equal to the square of the product of the characteristic impedances of the first and

second branches

342, 332a, the width of which may be calculated from the calculated characteristic impedance. Of course, in other embodiments, the width of the decoupling transmission line 33a may also be varied in 3, 4, or more levels. It will be appreciated that the width of the decoupling transmission line 33a may vary continuously.

In some embodiments,

branches

334a and 335a (shown in fig. 6) may be further disposed on decoupling transmission line 33a, and

branches

334a and 335a may be disposed on third segment 333a to adjust the transmission characteristics of the decoupling network.

The length of the second transmission line 32a may be 3/4 λ. In the embodiment shown in fig. 6, the second transmission line 32a forms a pattern on the layer where the decoupling transmission line 33 is located, which is bent or curved in a direction away from the decoupling transmission line 33.

The above has been described for two

antenna elements

10a and 20a, a first and a second decoupling network 30, 30' and a decoupling transmission line 3. However, it is easily understood that the decoupling structure of the present application may also be provided for the

antenna units

20a and 10b, or the decoupling structure of the present application may also be similarly provided for the

antenna units

10b and 20b (as shown in fig. 6). For example, a third and a fourth decoupling network 35, 35 ' and a decoupling transmission line 33a ' connected between the third and the fourth decoupling network 35, 35 ' can be provided for the

antenna units

10b and 20 a. The third decoupling network 35 may be identical or similar to the first decoupling network 30 described above, and the fourth decoupling network 35 'may be identical or similar to the second decoupling network 30' described above. The third decoupling transmission line 33 a' may be the same as or similar to the decoupling transmission line 33a described above.

When more than three antenna elements are used as shown in fig. 6, these decoupling networks and decoupling transmission lines may also be distributed in different layers. For example, the first and second decoupling networks 30 and 30 'and the decoupling transmission line 33a connected therebetween may be distributed at the level of the metal layer 666 shown in fig. 7, and the third and fourth decoupling networks 35 and 35' and the decoupling transmission line 33a 'connected between the third and fourth decoupling networks 35 and 35' may be distributed at the level of the metal layer 667 shown in fig. 7.

Referring to fig. 8, a schematic diagram of an antenna apparatus according to another embodiment of the present application is shown. In the antenna device 60 of this embodiment, for example, the top end portion of the middle frame 42 of the mobile phone may be divided into two sections by the slit 44, and the two sections may be used as the first antenna 10a and the second antenna 20a, respectively. A circuit board 43 may be provided in the middle frame 42, and the first and second decoupling networks 30 and 30' and the decoupling transmission line 33 (see fig. 3) described above in the present application may be disposed on the circuit board 43. The first feed 40 and the second feed 40' may be connected to the circuit board 43, which circuit board 43 in turn is connected to the first antenna 10a and the second antenna 20 a. The slot 44 may be generally non-centrally located, such as near the left or right side of the center frame 42.

Referring to fig. 9, 10 and 11, fig. 9 is a top view of an antenna device according to another embodiment of the present application. Fig. 10 is a front view of two antenna units in fig. 9, and fig. 11 is a perspective view of one antenna unit in fig. 9, wherein the substrate of the antenna device is omitted in each of fig. 10 and 11. The antenna arrangement comprises a patch array 710, a ground plane 720, a feed 730, a feed 740 and a decoupling network. Wherein the decoupling network may be the decoupling network of any of the embodiments described above. For example, a first decoupling network 30 and a second decoupling network 30' are shown. The patch array 710 is spaced from the ground plane 720 by a substrate (not shown). The ground plane 720 is spaced from the decoupling network 750 by a substrate (not shown). The ground feed portion 730 electrically connects the patch array 710 and the ground layer 720; the feeding portion 740 includes a first feeding element 741 and a second feeding element 742 arranged in a cross-isolation manner, and the first feeding element 741 and the second feeding element 742 are respectively used for feeding current signals to excite the patch array 720 and the ground feeding portion 730 to resonate in corresponding frequency bands. Specifically, the first feeding element 741 and the second feeding element 742 are respectively used for feeding different current signals, so that the patch array 720 and the ground feeding portion 730 can be excited to resonate in different frequency bands, and dual-frequency dual polarization can be realized. The first feeding element 741 and the second feeding element 742 feed the same current signal, which can excite the patch array 720 and the ground feeding portion 730 to resonate in the same frequency band, thereby enhancing the signal strength.

In some embodiments, the chip array 710 includes a first radiator 711, a second radiator 712, a third radiator 713, and a fourth radiator 714 that are disposed apart from each other. The first radiator 711, the second radiator 712, the third radiator 713, and the fourth radiator 714 are all metal patches, and the patch array 710 has a mirror-symmetric structure and forms a mesh structure. The first radiator 711, the second radiator 712, the third radiator 713, and the fourth radiator 714 arranged in a cross form a cross slot therebetween.

The feeding portion 740 is disposed corresponding to a gap between the first radiator 711, the second radiator 712, the third radiator 713, and the fourth radiator 714. The feeding portion 740 transmits current to the first radiator 711, the second radiator 712, the third radiator 713, and the fourth radiator 714 by coupling feeding so that the first radiator 711, the second radiator 712, the third radiator 713, and the fourth radiator 714 resonate. At this time, when the current signal of the feeding portion 740 is coupled to the first radiator 711, the second radiator 712, the third radiator 713 and the fourth radiator 714, the current flows in the first radiator 711, the second radiator 712, the third radiator 713 and the fourth radiator 714 more uniformly, so that the radiation performance of the antenna device is more stable.

The first feed 741 is disposed at least partially across one slot in the patch array 710 and the second feed 742 is disposed at least partially across another slot in the patch array 710. The first feeding element 741 is configured to feed a first current signal, the first current signal is coupled to the patch array 710 to excite the patch array 710 to resonate in a first frequency band, the first current signal is coupled to the ground feeding portion 730 to excite the ground feeding portion 730 to resonate in a second frequency band, and the first frequency band may be the same as the second frequency band or different from the second frequency band. The second feeding element 742 is configured to feed a second current signal, the second current signal is coupled to the patch array 710 to excite the patch array 710 to resonate in a third frequency band, the second current signal is coupled to the ground feeding portion 730 to excite the ground feeding portion 730 to resonate in a fourth frequency band, and the third frequency band may be the same as the fourth frequency band or different from the fourth frequency band. The first feed 741 and the second feed 742 are arranged in a cross-isolation manner, and when the first feed 741 and the second feed 742 are orthogonal to each other, the direction of the current flowing through the first feed 741 and the direction of the current flowing through the second feed 742 are orthogonal to each other, so that the antenna device has a dual-polarization characteristic.

The ground feeding portion 730 includes a first ground feeding part 731 and a second ground feeding part 732, the first ground feeding part 731 is electrically connected to the first radiator 711 and the ground layer 720, and the second ground feeding part 732 is electrically connected to the first radiator 711 and the ground layer 720. The ground feed portion 730 further includes a third ground feed 733 and a third ground feed 734, the third ground feed 733 is electrically connected to the second radiator 712 and the ground layer 720, and the fourth ground feed 734 is electrically connected to the second radiator 712 and the ground layer 720. It is understood that a ground feeding element is also connected between the third radiator 713 and the ground layer 720, and a ground feeding element is also connected between the fourth radiator 714 and the ground layer 720, which has a similar structure to that of the ground feeding element between the first radiator 711 and the ground layer 720, and therefore will not be described herein again. The radiator may be referred to as an electric dipole, and the ground feed portion may be referred to as a magnetic dipole. In some embodiments, an antenna device may include a plurality of electric dipoles, magnetic dipoles in one-to-one correspondence with the plurality of electric dipoles, and first, second, and third substrates. The plurality of electric dipoles are arranged on the surface of the first substrate far away from the second substrate and are mutually spaced. A plurality of magnetic dipoles are disposed within the second substrate and the first substrate and are coupled between the ground plane and corresponding electric dipoles. A decoupling network is disposed within the third substrate and spaced from the ground plane. The antenna unit of the present embodiment may include a patch array 710, a ground feed 730, and a feed 740.

It will be readily appreciated that the decoupling network of the present application can be applied to a variety of antenna element types and is not limited to the antenna element types of the above-described embodiments.

The present embodiment takes as an example a decoupling design with a four-element linear array as shown in fig. 9, which has a center operating frequency of 28 GHz. It is noted that according to the 3GPP TS 38.101 protocol, frequencies between 24.25GHz and 52.6GHz are commonly referred to as millimeter waves (mm Wave); therefore, the decoupling structure provided by the application can be a millimeter wave array antenna decoupling structure. Fig. 12 shows an isolation contrast curve for the antenna elements before and after connection of the decoupling network. As can be seen from fig. 12, after the decoupling network is connected, the isolation between the antenna elements increases at 26.2GHz to 33GHz and 37.4GHz to 39.6GHz, and broadband mutual coupling suppression is achieved, and the dual-band mutual coupling suppression is achieved.

Figure 13 shows a reflection parameter curve for an isolated antenna element before decoupling. As can be seen from FIG. 13, the-6 dB operating bandwidths of the antenna elements in the pre-decoupled array are 24.4 GHz-31.3 GHz and 35 GHz-40.1 GHz. Figure 14 shows a reflection parameter curve for the antenna element after decoupling. As can be seen from FIG. 14, the-6 dB operating bandwidths of the antenna elements in the array after decoupling are 24.1 GHz-29.7 GHz and 35.7 GHz-45.0 GHz. Thus, a dual band matching improvement is achieved.

Fig. 15-17 are gain sweep comparison curves for the antenna device when the beams are swept to 0 °, 45 °, and 50 ° before and after connecting the decoupling network. As can be seen from fig. 15: when the wave beam points to 0 degree, in the frequency range of 27 GHz-29 GHz, the gain after decoupling is improved compared with that before decoupling. The gain loss after decoupling is less than 0.5dB in frequency ranges of 24.25 GHz-27 GHz, 29 GHz-29.6 GHz and 37 GHz-40 GHz. As shown in fig. 16, when the beam is directed at 45 °, the gain after decoupling is improved in frequency ranges of 24GHz to 29.8GHz and 37GHz to 41GHz compared with that before decoupling, wherein the gain is improved by 1.34dB to the maximum at a frequency of 24.5 GHz. As shown in fig. 17, when the beam is directed at 50 °, the gain after decoupling is improved in frequency ranges of 24GHz to 30GHz and 37GHz to 41GHz compared with that before decoupling, and the maximum gain improvement value at 24.5GHz is 1.55 dB. Therefore, after the decoupling network is connected, when the scanning is carried out to 0 degrees, 45 degrees and 50 degrees, the gain is improved, and the radiation capability of the array antenna is obviously improved.

Referring to fig. 18, a decoupled network transmission coefficient curve is shown. As can be seen from fig. 18, the transmission performance of the decoupling network in the dual frequency bands is improved, and the insertion loss is less than 0.7dB in both the frequency ranges of 24.5GHz to 29.6GHz and 37GHz to 40 GHz. Referring to fig. 19, the reflection parameters of the decoupling network are shown. As can be seen from fig. 19, the matching performance of the decoupling network in the dual band is improved, and the frequency ranges of the operating bandwidth of-10 dB are 23.6GHz to 30.3GHz and 36.7GHz to 40.4 GHz. Therefore, the design of annular cancellation is adopted, and the transmission performance and the matching performance of the decoupling network in the double frequency bands are improved.

To sum up, the antenna device of this application introduces the concept of decoupling network in antenna element below, need not to change the structure of array antenna unit, only needs to dispose decoupling transmission line' S length and the S parameter of three-port network, can accurately define the coupling degree between the antenna element, can reduce the mutual coupling between the antenna element, expands the scanning angle, promotes scanning gain. Furthermore, the power dividing ratio of the directional power divider can be calculated according to the amplitude of the isolation degree before decoupling, the characteristic impedance of each branch of the power divider is determined according to a formula, and then the width of a transmission line corresponding to the characteristic impedance can be calculated, so that the power divider can be manufactured. Based on the method, the isolation of the multi-antenna system can be improved.

In addition, the decoupling network of the application comprises a closed loop structure, the closed loop structure is provided with a first output port and a second output port, a slot is formed in the antenna floor, and at least one part of the slot is overlapped with the closed loop structure, so that the interference influence between the first output port and the second output port of the power divider can be reversed in equal amplitude and mutually offset, the first output port and the second output port can not influence each other any more, and the isolation degree between the two output ports of the power divider main body can be remarkably improved. In addition, an isolation resistor is not required to be arranged between the two output ports of the power divider main body, and insertion loss can be reduced.

The above description is only an example of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings, or which are directly or indirectly applied to other related technical fields, are intended to be included within the scope of the present application.

Claims

1. An antenna device, comprising:

a plurality of spaced apart antenna elements;

a plurality of decoupling networks in one-to-one correspondence with the plurality of antenna elements, each of the decoupling networks including a closed loop structure and first and second transmission lines connected to the closed loop structure; the closed-loop structure is provided with a first output port and a second output port, the first transmission line is used for being connected with the radio frequency chip, one end of the second transmission line is connected with the first output port, and the other end of the second transmission line is connected with the corresponding antenna unit;

a decoupling transmission line connected between the second output ports of adjacent decoupling networks;

and the grounding layer is overlapped with the decoupling networks at intervals, the grounding layer is provided with a slot, and at least one part of the slot is overlapped with the closed loop structure.

2. The antenna device of claim 1, wherein the slots enclose an axisymmetric pattern; the closed loop structure is in an axisymmetric pattern; the axis of symmetry of the slot overlaps the axis of symmetry of the closed loop structure.

3. The antenna device according to claim 1, characterized in that the slot encloses a closed shape.

4. The antenna device according to claim 1, characterized in that the closed loop structure comprises a first branch, a second branch and a microstrip connection line;

the first end of the first branch and the first end of the second branch are connected to the same end of the first transmission line; a second end of the first branch forms the first output port; a second end of the second branch forms the second output port;

the microstrip connection line is connected between the first output port and the second output port.

5. The antenna device according to claim 4, wherein the first branch, the second branch and the microstrip connection line enclose a circular ring, an elliptical ring or a polygon.

6. The antenna device according to claim 4, characterized in that the first branch and the second branch are equal in length; alternatively, the difference in length between the first branch and the second branch is equal to the wavelength.

7. The antenna device according to claim 4, wherein the slot comprises a closed-loop groove and a strip-shaped groove extending from the closed-loop groove, at least a portion of the strip-shaped groove overlapping the closed-loop structure.

8. The antenna device according to claim 7, wherein at least a portion of the strip-shaped groove overlaps the microstrip connection line, and the microstrip connection line is symmetrically disposed with respect to the strip-shaped groove; the closed loop structure and the closed loop groove are symmetrical relative to the straight line where the strip-shaped groove is located.

9. The antenna device of claim 7, wherein the closed-loop groove is circular, elliptical, or polygonal.

10. The antenna device according to claim 4, wherein a characteristic impedance changes in a stepwise manner from the second branch to an intermediate position of the decoupled transmission line.

11. The antenna device according to claim 4, wherein the isolation of the adjacent antenna units when the decoupling network is not connected is defined as an initial isolation;

the first branch, the second branch and the microstrip connecting line form a power divider;

the power divider has a power dividing ratio which satisfies the following relationship with the strength of the initial isolation, and the length of the decoupling transmission line satisfies the following relationship with the phase of the initial isolation:

wherein S' 12 is the strength of the initial isolation; s12 and S13 are scattering parameters of the decoupling network;

the power dividing ratio is used; phi'₁₂A phase that is the initial isolation; d5 is the length of the decoupled transmission line and k is the wavenumber.

12. The antenna device according to claim 11, wherein the characteristic impedance of the first branch and the characteristic impedance of the first transmission line, the strength of the initial isolation satisfy the following relationship:

Z2＝(1+|S’12|)ⅹZ1；

wherein Z1 is the characteristic impedance of the first transmission line and Z2 is the characteristic impedance of the first branch.

13. The antenna device according to claim 11, wherein the characteristic impedance of the second branch and the characteristic impedance of the first transmission line, the strength of the initial isolation satisfy the following relationship:

wherein Z1 is the characteristic impedance of the first transmission line and Z3 is the characteristic impedance of the second branch.

14. The antenna device according to claim 1, further comprising a first substrate, a second substrate, and a third substrate which are stacked in this order;

the plurality of antenna units are arranged on the first substrate;

the grounding layer is arranged between the second substrate and the third substrate;

the plurality of decoupling networks are disposed within the third substrate; the decoupling networks are spaced apart from the ground layer by a portion of the third substrate.

15. The antenna device according to claim 14, wherein the third substrate is a multilayer structure, and the decoupling transmission line is provided on a layer of the third substrate; the decoupling networks are in the same layer as the decoupling transmission line.

16. The antenna device according to claim 14, wherein each antenna unit comprises:

a plurality of electric dipoles arranged on the surface of the first substrate far away from the second substrate, wherein the plurality of electric dipoles are mutually spaced; and

and the magnetic dipoles are arranged in the second substrate and the first substrate and are connected between the ground layer and the corresponding electric dipoles.

17. The antenna device according to claim 1, wherein the degree of coupling between adjacent antenna elements is determined based on the length of the decoupling transmission line and scattering parameters of the decoupling network to which the antenna elements correspond.

18. The antenna device according to claim 1, wherein the following relationship is satisfied between the coupling degree between adjacent antenna units and the length of the decoupling transmission line and the scattering parameter of the corresponding decoupling network:

wherein S' 12 is the strength of the initial isolation between the adjacent antenna units, and the initial isolation is the isolation when the adjacent antenna units are not connected to the decoupling network; the S12 and S13 are scattering parameters of the decoupling network; d5 is the length of the decoupled transmission line, k is the wavenumber, e is the natural constant, and j is the notation of an imaginary number.

19. An electronic device, comprising:

a shell body, a plurality of first connecting rods and a plurality of second connecting rods,

the display screen assembly is connected with the shell and forms an accommodating space with the shell;

the radio frequency chip is arranged in the accommodating space; and

an antenna device at least partially disposed in the accommodating space, the antenna device comprising:

a plurality of spaced apart antenna elements;

20. The electronic device according to claim 19, wherein the antenna device further comprises a first substrate, a second substrate, and a third substrate which are sequentially stacked;

the plurality of antenna units are arranged on the first substrate;

the plurality of decoupling networks are disposed within the third substrate; the decoupling networks and the grounding layer are separated by a part of the third substrate;

the radio frequency chip is arranged on one side of the third substrate far away from the second substrate.