CN217114786U - Electronic equipment for improving antenna radiation performance - Google Patents

Abstract

The embodiment of the application provides an electronic equipment for improving antenna radiation performance, which comprises a rear cover, a circuit board and a millimeter wave antenna module. The millimeter wave antenna module is arranged on one side of the circuit board facing the rear cover and used for transmitting and receiving millimeter wave electromagnetic wave signals. The rear cover comprises a first part and a second part which are arranged along a preset direction, the dielectric constant of the first part is different from that of the second part, the first part is arranged corresponding to the millimeter wave antenna module of the electronic device, the projection of the millimeter wave antenna module on the rear cover is located in the first part of the rear cover, or the projection range of the beam of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module on the rear cover is located in the first part of the rear cover. The rear cover is provided with the first part with the specific dielectric constant, so that the transmissivity of millimeter wave electromagnetic wave signals can be effectively improved at the first part of the rear cover, and the radiation performance of the antenna is improved.

Description

Electronic equipment for improving antenna radiation performance

Technical Field

The application relates to the technical field of communication, especially, relate to an electronic equipment who promotes antenna radiation performance.

Background

An antenna is an important component of an electronic device as an element for transmitting and receiving electromagnetic waves. At present, with the development of 5G technology, the number of antennas required is increasing, and some antennas are arranged on a circuit board of an electronic device. After the electronic equipment is assembled, the antenna arranged on the circuit board is shielded by the rear cover, and the antenna needs to receive and send millimeter wave electromagnetic wave signals through the rear cover. Due to the existence of the rear cover, millimeter wave electromagnetic wave signals can be reflected or lost to a certain degree, so that the attenuation of the millimeter wave electromagnetic wave signals is large, and the radiation performance of the antenna is influenced.

SUMMERY OF THE UTILITY MODEL

The application provides an electronic equipment for improving antenna radiation performance, can effectively avoid the influence to millimeter wave electromagnetic wave signal, promotes antenna radiation performance.

In a first aspect, the present application provides an electronic device for improving antenna radiation performance, including a rear cover, a circuit board, and a millimeter wave antenna module. The millimeter wave antenna module is arranged on one side of the circuit board, which faces the rear cover, and is used for transmitting and receiving millimeter wave electromagnetic wave signals; the rear cover comprises a first part and a second part which are arranged along a preset direction, the dielectric constant of the first part is different from that of the second part, the first part is arranged corresponding to the millimeter wave antenna module of the electronic device, the projection of the millimeter wave antenna module on the rear cover is located in the first part of the rear cover, or the projection range of the beam of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module on the rear cover is located in the first part of the rear cover. Therefore, in this application, through improving the back lid for the first part that corresponds millimeter wave antenna module has corresponding dielectric constant, is covered by the back lid under the circumstances at millimeter wave antenna module, can make the first part transmission of millimeter wave electromagnetic wave signal all or most accessible, realizes the effect of total transmission or most transmission.

In one possible embodiment, the predetermined direction is a direction perpendicular to a thickness direction of the rear cover, the first portion is located in a first region of the rear cover, the second portion is located in a second region of the rear cover other than the first region, and the first region and the second region do not overlap in the thickness direction. Therefore, the first part and the second part are distributed in two areas of the rear cover along the direction perpendicular to the thickness direction of the rear cover, the original appearance of the rear cover can be kept, and the original layout of the whole machine is not affected.

In one possible embodiment, the first dielectric constant satisfies that a half wavelength of the medium when the millimeter wave electromagnetic wave signal passes through the first portion of the back cover is equal to a thickness of the first portion of the back cover. Therefore, under the relation that the first dielectric constant satisfies that the half wavelength of the medium when the millimeter wave electromagnetic wave signal passes through the first part of the back cover is equal to the thickness of the first part of the back cover, the millimeter wave electromagnetic wave signal can be completely or mostly transmitted through the first part, and the effect of complete transmission or mostly transmission is achieved.

In one possible embodiment, the first dielectric constant satisfies the formula: t × sqrt (∈) ═ λ 0/2, where T is the thickness of the first portion of the back cover, ∈ is the first dielectric constant, and λ 0 is the wavelength of the millimeter-wave electromagnetic wave signal when propagating in air. Wherein, since λ/sqrt (ε) is the medium wavelength, the first dielectric constant satisfies the formula, i.e., T is equal to 1/2 medium wavelength.

In one possible embodiment, the thickness of the first portion of the back cover is the same as the thickness of the second portion of the back cover. Because the first part and the second part are distributed in two areas of the rear cover along the direction vertical to the thickness direction of the rear cover, and the thicknesses of the first part and the second part are the same, the rear cover can be integrally formed, and the processing is convenient.

In one possible embodiment, the predetermined direction is a thickness direction of the rear cover, the first portion is a dielectric matching layer, the second portion is a rear cover body, and the dielectric matching layers are stacked on one side of the rear cover body in the thickness direction. Through will be the range upon range of the first part of dielectric matching layer and set up in the second part one side as the back lid body, can increase this dielectric matching layer and can realize the total transmission of millimeter wave electromagnetic wave signal on the basis of original back lid, easily processing preparation.

In one possible embodiment, the dielectric matching layer is disposed on a side of the rear cover body facing the circuit board. Therefore, the medium matching layer is arranged on the side, facing the circuit board, of the rear cover body, and the integrity of the appearance of the rear cover can be kept.

In one possible embodiment, the thickness and dielectric constant of the dielectric matching layer are related to the thickness and dielectric constant of the back cover body.

In one possible embodiment, the thickness T2 of the dielectric matching layer satisfies the formula: t1 · (∈ 1) + T2 · (∈ 2) ═ λ 0/2, where T1 is the thickness of the back cover body, ∈ 1 is the dielectric constant of the back cover body, T2 is the thickness of the dielectric matching layer, ∈ 2 is the dielectric constant of the dielectric matching layer, and λ 0 is the wavelength of the millimeter-wave electromagnetic wave signal when propagating in the air. By satisfying the formula, the thickness of the structure which is formed by the rear cover body and the medium matching layer and can be regarded as a single-layer medium is 1/2 medium wavelength, so that the return loss is effectively reduced, and the full transmission or at least the most transmission of the energy of the millimeter wave electromagnetic wave signals is realized.

In one possible embodiment, the dielectric constant of the dielectric matching layer is greater than the dielectric constant of the back cover body. On the premise that the thickness is equal to 1/2 medium wavelength, the dielectric constant and the thickness are in inverse proportion, so that the dielectric constant of the medium matching layer can be set to be larger, the thickness of the medium matching layer is made to be thinner, and the thickness of the whole machine is not influenced.

In one possible embodiment, the dielectric matching layer is stacked on a partial region or a whole region of one side of the rear cover body.

The electronic equipment at least enables the rear cover to effectively improve the transmissivity of millimeter wave electromagnetic wave signals at the first part by arranging the first part with the specific dielectric constant in the rear cover, reduces or even avoids the reflection of the millimeter wave electromagnetic wave signals, and improves the radiation performance of the antenna.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments or the background art of the present application, the drawings required to be used in the embodiments or the background art of the present application will be described below.

Fig. 1 is a schematic structural diagram of an electronic device for improving antenna radiation performance according to an embodiment of the present disclosure;

FIG. 2 is a schematic top view of a rear cover of the electronic device of FIG. 1;

FIG. 3 is a schematic cross-sectional diagram illustrating a partial structure of an electronic device for improving radiation performance of an antenna, according to an embodiment;

FIG. 4 is a schematic diagram illustrating millimeter wave electromagnetic wave signals transmitted through the first portion of the back cover shown in FIG. 3;

fig. 5 is a schematic diagram of return loss obtained by simulating millimeter wave electromagnetic wave signals under a plurality of conditions of a rear cover in the embodiment of the present application;

fig. 6 is a schematic plan view of a millimeter wave antenna module according to an embodiment of the present application;

fig. 7 to 10 are antenna radiation patterns of millimeter wave electromagnetic wave signals in the case of the foregoing four rear covers in the embodiment of the present application, respectively;

fig. 11 is a schematic cross-sectional view illustrating a partial structure of an electronic device for improving antenna radiation performance according to another embodiment of the present application;

FIG. 12 illustrates a schematic view of millimeter wave electromagnetic wave signals transmitted through the back cover from the first portion of the back cover shown in FIG. 11;

fig. 13 is another cross-sectional view of a schematic partial structure of an electronic device for improving antenna radiation performance in another embodiment of the present application;

FIG. 14 is an antenna radiation pattern of millimeter wave electromagnetic wave signals without a back cover in an embodiment of the present application;

fig. 15 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal in the case where the rear cover does not include a dielectric matching layer in the embodiment of the present application;

fig. 16 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal in the case where the back cover includes the dielectric matching layer in the embodiment of the present application;

fig. 17 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal when the back cover in the embodiment of the present application includes a dielectric matching layer having a specific dielectric constant and thickness;

fig. 18 is a schematic cross-sectional view of a millimeter wave antenna module according to an embodiment of the present application.

Detailed Description

The embodiments of the present application will be described below with reference to the drawings.

Referring to fig. 1, fig. 1 is a schematic structural diagram of an electronic device 1000 (referred to as an electronic device in the present application for short) for improving antenna radiation performance according to an embodiment of the present application.

The electronic device 1000 may be an electronic product with a wireless communication function, such as a handheld device, a vehicle-mounted device, a wearable device, a computer device, a Wireless Local Area Network (WLAN) device, or a router. In some application scenarios, the electronic device 1000 may also be called a different name, for example: user equipment, access terminal, subscriber unit, subscriber station, mobile station, remote terminal, mobile device, user terminal, wireless electronic device, user agent or user equipment, cellular telephone, wireless telephone, Session Initiation Protocol (SIP) telephone, Wireless Local Loop (WLL) station, Personal Digital Assistant (PDA), terminal equipment in a 5G network or future evolution network, and the like.

In some embodiments, the electronic device 1000 may also be a device deployed in a wireless access network to provide wireless communication functions, including but not limited to: base stations, relay stations, access points, in-vehicle devices, wireless-fidelity (Wi-Fi) stations, wireless backhaul nodes, small stations, micro-stations, and so forth. The base station may be a Base Transceiver Station (BTS), a Node B (NodeB, NB), an evolved Node B (eNB or eNodeB), a transmission Node or a transmission point (TRP or TP) in an nr (new radio) system, or a next generation Node B (gNB), a base station in a future communication network, or a network device. In the embodiment of the present application, the electronic device 1000 is a mobile phone as an example.

The electronic device 1000 includes a housing 100, a display module 200, a circuit board 300, a receiver (not shown), and a speaker (not shown), wherein the display module 200 is mounted on the housing 100 and cooperates with the housing 100 to form a receiving cavity, and the circuit board 300, the receiver, and the speaker are mounted in the receiving cavity.

The case 100 may include a bezel 110 and a rear cover 120, and the rear cover 120 is fixed to one side of the bezel 110. The bezel 110 and the rear cover 120 may be integrally formed to ensure structural stability of the housing 100. Alternatively, the bezel 110 and the rear cover 120 may be fixed to each other by an assembling method. The case 100 is provided with the speaker holes 1001, and the number of the speaker holes 1001 may be one or more. Illustratively, the number of the speaker holes 1001 is plural, and the plural speaker holes 1001 are provided in the bezel 110. The speaker hole 1001 communicates the inside of the case 100 with the outside of the case 100. It should be noted that the term "pore" described in the embodiments of the present application refers to a pore having a complete pore wall.

The display module 200 is fixed to the other side of the frame 110. The display module 200 and the rear cover 120 are respectively fixed to two sides of the frame 110. When the user uses the electronic device 1000, the display module 200 is placed toward the user, and the rear cover 120 is placed away from the user. The display module 200 is provided with a receiver 2001, and the receiver 2001 is a through hole penetrating through the display module 200. The face where the display module 200 is located is the front face of the electronic device 100, the face of the electronic device 100 away from the display module 200 is the back face of the electronic device 100, and the rear cover 120 is used for covering the back face of the electronic device 1000. The display module 200 includes a display screen and a driving circuit thereof. The display module 200 may be a touch display module.

The circuit board 300 is located between the rear cover 120 and the display module 200. The circuit board 300 may be a main board (main board) of the electronic device 1000. The receiver is located at the top of the electronic device 1000, and sound emitted by the receiver is transmitted to the outside of the electronic device 1000 through the receiver 2001, so as to realize a sound playing function of the electronic device 1000. The speaker is located at the bottom of the electronic device 1000, and sound emitted by the speaker can be transmitted to the outside of the electronic device 1000 through the sound emitting hole 1001, so as to realize a sound playing function of the electronic device 1000.

It should be understood that the terms "top" and "bottom" used in the description of the electronic device 1000 in the embodiments of the present application are mainly set forth according to the orientation of the user when the user holds the electronic device 1000 in hand, and the terms "top" and "bottom" are used in the directions of the top side of the electronic device 1000 and the bottom side of the electronic device 1000, and do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, should not be interpreted as limiting the orientation of the electronic device 1000 in the practical application scenario. In some embodiments, the bottom of the electronic device 1000 is the end provided with the earphone hole and the USB hole, and the top of the electronic device 1000 is the other end opposite to the end provided with the earphone hole and the USB hole.

In the embodiment of the present invention, the thickness of the rear cover 120 refers to a distance between the inner and outer surfaces of the rear cover 120, the inner and outer surfaces of the rear cover 120 refer to surfaces of the rear cover 120 that are substantially parallel to the screen of the display module 200, and the thickness direction refers to a direction perpendicular to the inner and outer surfaces of the rear cover 120, that is, a direction perpendicular to the screen of the display module 200.

Referring to fig. 2, fig. 2 is a schematic top view of the back cover 120 of the electronic device 1000 shown in fig. 1. As shown in fig. 2, the rear cover 120 includes a first portion B1 and a second portion B2 arranged in a predetermined direction, and the dielectric constant of the first portion B1 is different from that of the second portion B2.

Among other things, the second portion B2 may be a structural portion that the back cover 120 originally had before modification. In the present application, by providing the first portion B1, which is a portion with a specific dielectric constant, in the rear cover 120, at least the rear cover 120 in the first portion B1 can effectively improve the transmittance of the millimeter wave electromagnetic wave signals, reduce or even avoid the reflection of the millimeter wave electromagnetic wave signals, and improve the radiation performance of the antenna.

Here, the preset direction may be a direction perpendicular to the thickness direction of the rear cover or a direction parallel to the thickness direction of the rear cover, and thus, the first portion B1 in fig. 2 is illustrated by a dotted line. The top view of the back cover 120 shown in fig. 2 is a top view of the electronic device 1000 with the display module 200 facing downward and viewed from the outer surface side of the back cover 120.

Referring to fig. 3, fig. 3 is a schematic cross-sectional view illustrating a partial structure of an electronic device 1000 according to an embodiment. As shown in fig. 3, electronic device 1000 includes a circuit board 300 and a millimeter wave antenna module 400 disposed on circuit board 300, where millimeter wave antenna module 400 is disposed on circuit board 300 on a side facing back cover 120, and millimeter wave antenna module 400 is configured to transmit and receive millimeter wave electromagnetic wave signals.

The first portion B1 corresponds to the millimeter wave antenna module 400, the projection of the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1 of the rear cover 120, or the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1 of the rear cover.

That is, in some embodiments, the arrangement of first portion B1 corresponding to millimeter wave antenna module 400 means that the projection of millimeter wave antenna module 400 on back cover 120 is located in first portion B1 of back cover 120, and the area of first portion B1 may be greater than or equal to the area of the projection on back cover 120 of millimeter wave antenna module 400. Alternatively, the first portion B1 being provided in correspondence with the millimeter wave antenna module 400 means that the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located within the first portion B1 of the rear cover. The projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1 of the rear cover, and the beam W1 of most of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 passes through the first portion B1. The size of the first portion B1 may be determined according to the area of the rear cover 120 through which most of the millimeter wave electromagnetic wave signals emitted by the millimeter wave antenna module 400 pass.

It should be noted that fig. 3 schematically illustrates an embodiment in which the preset direction is a direction perpendicular to the thickness direction of the rear cover 120, and it is obvious that when the preset direction is a direction parallel to the thickness direction of the rear cover 120, that is, when the first portion B1 and the second portion B2 are stacked along the thickness direction of the rear cover 120, the first portion B1 is also disposed corresponding to the millimeter wave antenna module 400, the projection of the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1 of the rear cover 120, or the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1 of the rear cover.

As shown in fig. 3, in an embodiment, the predetermined direction is a direction perpendicular to the thickness direction of the rear cover 120, that is, a direction parallel to the inner and outer surfaces of the rear cover 120, the first portion B1 is located in a first region Z1 of the rear cover 120, the second portion B2 is located in a second region Z2 outside the first region Z1 of the rear cover, and the first region Z1 and the second region Z2 do not overlap in the thickness direction. That is, on a plane of the rear cover 120 parallel to the inner and outer surfaces of the rear cover 120, there is no overlapping area of the first and second regions Z1 and Z2. In one embodiment, first portion B1 and second portion B2 cooperate to form a complete rear cover 120.

As mentioned above, the first portion B1 is disposed corresponding to the mm-wave antenna module 400, and in this embodiment, when the first portion B1 is located in the first region Z1 of the rear cover 120, the first region Z1 is a region corresponding to the mm-wave antenna module 400.

The first region Z1 corresponding to the millimeter wave antenna module 400 means that the projection of the millimeter wave antenna module 400 on the rear cover 120 is located in the first region Z1 of the rear cover 120, or the projection range of the beam of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first region Z1 of the rear cover. The area of first region Z1 may be greater than or equal to the area of the projection on back cover 120 of millimeter-wave antenna module 400. The projection range of the beam of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first region Z1 of the rear cover, which means that the first region Z1 is a region of the rear cover 120 through which most of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 passes.

In an embodiment, when the first portion B1 and the second portion B2 are arranged along a direction perpendicular to the thickness direction of the rear cover 120, the periphery of the first portion B1 may be entirely surrounded by the second portion B2, and the first portion B1 may be a region near a narrow edge of the rear cover 120. That is, the millimeter-wave antenna module 400 may be disposed on the circuit board 300 near the narrow side of the electronic device 1000, and the first portion B1 may be correspondingly disposed near the narrow side of the rear cover 120 of the electronic device 1000. In some embodiments, first portion B1 can also be located at an edge of rear cover 120, at least one edge not encompassed by second portion B2.

The second part B2 of the rear cover 120 is the original structure part of the rear cover 120, that is, the part of the rear cover 120 before the improvement of the present application, because the design of the original rear cover 120 does not consider the problem of penetrability of the millimeter wave electromagnetic wave signal of the millimeter wave antenna module 400, and the millimeter wave electromagnetic wave signal is reflected or lost to a certain extent, and the attenuation of the millimeter wave electromagnetic wave signal is large, which affects the radiation performance of the antenna, in the present application, the rear cover 120 is improved, so that the first part B1 corresponding to the millimeter wave antenna module 400 has a corresponding dielectric constant, and under the condition that the millimeter wave antenna module is covered by the rear cover, the millimeter wave electromagnetic wave signal can be transmitted by the first part B1 in whole or most parts, and the effect of full transmission or most transmission is realized.

In the embodiment, the first portion B1 and the second portion B2 are distributed in two areas of the rear cover 120 along the direction perpendicular to the thickness direction of the rear cover 120, so that the original shape of the rear cover 120 can be maintained, and the original layout of the whole device is not affected.

Specifically, the dielectric constant of the first portion B1 is related to the thickness of the first portion B1, and the dielectric constant of the first portion B1 is adapted to the thickness of the first portion B1, so as to meet the requirement of penetration of the millimeter wave electromagnetic wave signals, and all or most of the millimeter wave electromagnetic wave signals transmitted or received by the millimeter wave antenna module 400 can penetrate through the first portion B1.

Wherein the first part B1 is made of a material having a first dielectric constant, and the second part B2 of the rear cover 120 is made of a material having a second dielectric constant, the first dielectric constant being different from the second dielectric constant.

Wherein the thickness of the first portion B1 of the rear cover 120 is the same as the thickness of the second portion B2 of the rear cover 120. That is, in one embodiment, the rear cover 120 is a unitary rear cover except that the first portion B1 and the second portion B2 are made of materials having different dielectric constants. Specifically, the rear cover 120 may be formed of the first portion B1 and the second portion B2 by an integral molding process using two materials having different dielectric constants. Since the first part B1 and the second part B2 are distributed in two areas of the rear cover 120 along the direction perpendicular to the thickness direction of the rear cover 120, and have the same thickness, they can be integrally formed, and are convenient to process.

The second portion B2 of the rear cover 120 is an original area of the improved front and rear covers 120, and the thickness of the rear cover 120 is designed based on the thickness of the whole device, so that the rear cover 120 generally reflects or loses millimeter wave electromagnetic wave signals to a certain extent, which results in great attenuation of the millimeter wave electromagnetic wave signals and affects the radiation performance of the antenna.

In the present embodiment, since the thickness of the first portion B1 of the rear cover 120 is the same as that of the second portion B2 of the rear cover 120, the first portion B1 may be formed of a material having a specific dielectric constant according to the originally required thickness of the rear cover 120, so that a region through which millimeter-wave electromagnetic wave signals can be transmitted can be formed.

When the first portion B1 and the second portion B2 are arranged along a direction perpendicular to the thickness direction of the rear cover 120, a coating layer with a specific color or pattern is further disposed on the outer surface of the rear cover 120, i.e., the surface far away from the display module 200, and the coating layer entirely covers the first portion B1 and the second portion B2, so that the outer surface of the rear cover 120 presents an overall appearance.

Wherein the first dielectric constant is associated with the thickness of the first portion B1, i.e. may be derived from the thickness of the first portion B1. Specifically, the first dielectric constant satisfies that the half-wavelength of the medium when the millimeter-wave electromagnetic wave signal passes through the first part B1 of the rear cover 120 is equal to the thickness of the first part B1 of the rear cover 120.

Referring to fig. 4, a schematic diagram of millimeter wave electromagnetic wave signals passing through the first portion B1 of the rear cover 120 shown in fig. 3 is shown.

As shown in fig. 4, the first dielectric constant satisfies that the half-wavelength of the medium when the millimeter wave electromagnetic wave signal W1 passes through the first portion B1 of the back cover 120 is equal to the thickness of the first portion B1 of the back cover 120, so that the phase of the millimeter wave electromagnetic wave signal when entering the first portion B1 differs from the phase after passing through the first portion B1 and passing out of the first portion B1 by half a wavelength, that is, by pi (180 °). Therefore, as shown in fig. 4, the amplitude of the millimeter wave electromagnetic wave signal W1 when entering the first section B1 is almost equal to the absolute value of the amplitude when it emerges from the first section B1, and thus, there is almost no energy loss, and full transmission or substantial transmission of the millimeter wave electromagnetic wave signal W1 is achieved.

Referring to fig. 5 and fig. 6, fig. 5 is a schematic diagram of return loss obtained by simulating millimeter wave electromagnetic wave signals under various conditions of the rear cover in the embodiment of the present application. Fig. 6 is a schematic plan view of a millimeter wave antenna module 400 according to an embodiment of the present application.

In an embodiment, the millimeter wave antenna module 400 takes the structure of the millimeter wave antenna module 400 shown in fig. 6 as an example, and the millimeter wave electromagnetic wave signal used in the simulation in fig. 5 is the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 shown in fig. 6.

Where the abscissa in fig. 5 is frequency (in GHz) and the ordinate is return loss, also referred to as S-parameter (in dB). Wherein, the multiple back cover condition includes condition one: a free space (no rear cover is arranged above the millimeter wave antenna module); 2) case two: a rear cover is arranged above the millimeter wave antenna module, the dielectric constant is equal to 28, and the thickness T is equal to 0.7 mm; 3) case three: a rear cover is arranged above the millimeter wave antenna module, the dielectric constant is equal to 28, and the thickness T is 1 mm; 4) case four: there is the back lid above the millimeter wave antenna module, and the dielectric constant equals 50, and thickness T equals 0.7 mm.

When various back covers are used for simulating millimeter wave electromagnetic wave signals, the back cover is a simulation back cover, which may be the same as or different from the back cover 120 in the embodiment of the present application, and the millimeter wave antenna module 400 is exemplified by the millimeter wave antenna module 400 shown in fig. 6.

As shown in fig. 6, in an embodiment, the millimeter wave antenna module 400 includes a plurality of antennas 401, and the plurality of antennas 401 form an antenna array. The millimeter wave antenna module 400 is used for transmitting and receiving millimeter wave electromagnetic wave signals, and means that the plurality of antennas 401 included in the millimeter wave antenna module 400 transmit and receive millimeter wave electromagnetic wave signals, a projection range of a beam W1 of the millimeter wave electromagnetic wave signals transmitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1, a projection range of a beam W1 of the millimeter wave electromagnetic wave signals transmitted by the plurality of antennas on the rear cover 120 is located in the first portion B1, a projection of the millimeter wave antenna module 400 on the rear cover 120 is located in the first portion B1, and a projection of the plurality of antennas on the rear cover 120 is located in the first portion B1. The antenna 401 is a millimeter wave antenna, and the antenna array formed by the multiple antennas 401 is a millimeter wave antenna array.

As shown in fig. 6, the millimeter wave antenna module 400 includes a first antenna 4011, a second antenna 4012, a third antenna 4013, and a fourth antenna 4014 arranged in a row.

Millimeter wave electromagnetic wave signals with the frequency of 28GHz, which are transmitted by the first antenna 4011, the second antenna 4012, the third antenna 4013 and the fourth antenna 4014, are used as test signals, the test signals can be obtained from the wavelength lambda upsilon/f, the wavelength of a free space is 10.7mm, upsilon is the propagation speed of the millimeter wave electromagnetic wave signals in the free space and is 3 x 10 ⁸ m/s, f is the electromagnetic frequency, i.e. 28GHz as described above.

Assuming that the wavelength of the millimeter wave electromagnetic wave signal propagating in the air (i.e., free space) is λ 0, the calculation formula of the medium wavelength when the millimeter wave electromagnetic wave signal propagates in a certain medium is as follows: λ r is λ 0/sqrt (ε), where ε refers to the dielectric constant of the medium and sqrt (ε) refers to the open square root of ε. Thus, when there is a back cover above the antenna with a dielectric constant equal to 28, the corresponding dielectric wavelength is 10.7mm/sqrt (28) ≈ 2mm, and when there is a back cover above the antenna with a dielectric constant equal to 50, the corresponding dielectric wavelength ≈ 1.4 mm. The medium wavelength in the present application is mainly up to the medium wavelength when the millimeter wave electromagnetic wave signal propagates in the medium of the back cover.

The first antenna 4011 and the fourth antenna 4014 are symmetrically arranged and are both arranged at the edge of the antenna array and are also called edge antennas, and the second antenna 4012 and the third antenna 4013 are symmetrically arranged and are both arranged in the middle of the antenna array and are also called middle antennas; fig. 5 is a schematic diagram of return loss obtained by simulating millimeter wave electromagnetic wave signals under various conditions of the rear cover, which mainly illustrates the return loss of the edge antenna represented by the first antenna 4011 and the return loss of the middle antenna represented by the second antenna 4012.

Wherein, let the situation one, that is, the input return loss of the first antenna 4011 in free space is S11-1, and the input return loss of the second antenna 4012 is S22-1; in the second case, namely, there is a back cover above the millimeter wave antenna module 400, the dielectric constant is equal to 28, and the thickness T is 0.7mm, the input return loss of the first antenna 4011 is S11-2, and the input return loss of the second antenna 4012 is S22-2; if the third condition is met, that is, there is a rear cover above the millimeter wave antenna module 400, the dielectric constant is equal to 28, and the thickness T is 1mm, the input return loss of the first antenna 4011 is S11-3, and the input return loss of the second antenna 4012 is S22-3; if there is a rear cover above the millimeter wave antenna module 400, the dielectric constant is equal to 50, and the thickness T is 0.7mm, the input return loss of the first antenna 4011 is S11-4, and the input return loss of the second antenna 4012 is S22-4. The input return loss is a reflection coefficient of the millimeter wave electromagnetic wave signal transmitted by the millimeter wave antenna module 400, and the lower the input return loss is, the smaller the loss of the millimeter wave electromagnetic wave signal is.

As shown in fig. 5, the input return loss S11-1 of the first antenna 4011 and the input return loss S22-1 of the second antenna 4012 in the first case, the input return loss S11-3 of the first antenna 4011 and the input return loss S22-3 of the second antenna 4012 in the third case, and the input return loss S11-4 of the first antenna 4011 and the input return loss S22-4 of the second antenna 4012 in the fourth case are all smaller and significantly smaller than the input return loss S11-2 of the first antenna 4011 and the input return loss S22-2 of the second antenna 4012 in the second case. Specifically, as shown in fig. 5, the input return loss S11-1 of the first antenna 4011 in case one is approximately-18 db, the input return loss S22-1 of the second antenna 4012 is approximately-13 db, the input return loss S11-3 of the first antenna 4011 in case three is approximately-21 db, the input return loss S22-3 of the second antenna 4012 is approximately-14 db, the input return loss S11-4 of the first antenna 4011 in case four is approximately-14 db, the output return loss S22-4 is approximately-11 db, the input return loss S11-2 of the first antenna 4011 in case two is approximately-0.5 db, and the input return loss S22-4 of the second antenna 4012 is approximately-1 db.

By way of analysis, the case one is a free space case, that is, there is no back cover above the millimeter wave antenna module 400, the thickness T of the back cover in the case three is 1mm, 1/2 of the dielectric wavelength 2mm when the dielectric constant in the case three is equal to 28, the thickness T of the back cover in the case four is 0.7mm, 1/2 of the dielectric wavelength 1.4mm when the dielectric constant in the case four is equal to 50, the thickness T of the case two is 0.7mm, 0.35 of the dielectric wavelength 2mm when the dielectric constant in the case two is equal to 28, and not 1/2 of the dielectric wavelength.

Therefore, it can be seen that when the thickness of the medium is 1/2 of the medium wavelength, that is, the thickness of the back cover is 1, 2 of the medium wavelength corresponding to the dielectric constant of the back cover, the return loss of the millimeter wave electromagnetic wave signals emitted by each antenna 401, no matter the antenna is located at the edge or the antenna is located in the middle, can be effectively reduced, that is, reflection is reduced, so that all or most of the millimeter wave electromagnetic wave signals can be directly transmitted, and the signal quality is effectively improved. On the other hand, as seen from fig. 5, when the thickness of the medium is 1/2 of the medium wavelength, the return loss in some cases is lower than that in free space propagation, and thus, when the thickness of the medium is 1/2 of the medium wavelength, the signal can be enhanced to some extent.

Therefore, in the present embodiment, when the thickness of the first portion B1 of the back cover 120 is the same as the thickness of the second portion B2 of the back cover 120, that is, the thickness is determined by the original thickness of the back cover 120, the first dielectric constant needs to satisfy that the half-wavelength of the medium when the millimeter-wave electromagnetic wave signal passes through the first portion B1 of the back cover 120 is equal to the thickness of the first portion B1 of the back cover 120.

That is, in the present embodiment, the first portion B1 is formed by selecting a material having a corresponding first dielectric constant such that the half-wavelength of the medium at which the millimeter-wave electromagnetic wave signal passes through the first portion B1 of the back cover 120 is equal to the thickness of the first portion B1 of the back cover 120, thereby allowing the millimeter-wave electromagnetic wave signal to be entirely transmitted/transmitted from the first portion B1, or at least to be mostly transmitted from the first portion B1.

Specifically, the first dielectric constant satisfies a first formula: t × sqrt (∈) ═ λ 0/2, where T is the thickness of the first portion B1 of the rear cover 120, ∈ is the first dielectric constant, and λ 0/2 is the half wavelength of the millimeter wave electromagnetic wave signal propagating in free space (i.e., in air).

The first formula can also be converted to: the thickness T λ/2sqrt (∈), and as previously discussed, the wavelength in the medium is calculated by the formula: λ r ═ λ 0/sqrt (∈), so that, at the first dielectric constant, the first formula is satisfied: when T × sqrt (∈) ═ λ 0/2, the thickness T1 of the first portion B1 of the rear cover 120 will be equal to 1/2 of the medium wavelength λ r, thereby effectively reducing the return loss and increasing the signal strength.

In some embodiments, since the original thickness of the back cover 120 is relatively thin, and the thickness is inversely proportional to the dielectric constant according to the thickness T ═ λ/2sqrt (∈), the original region of the back cover 120, that is, the second portion B2, may not be able to transmit the millimeter wave electromagnetic wave signals because the thickness is smaller than λ 0/2. Accordingly, by selecting a first dielectric constant that is greater than a second dielectric constant, it is satisfied that the half wavelength of the medium at which the millimeter-wave electromagnetic wave signal passes through the first portion B1 of the back cover 120 is equal to the thickness of the first portion B1 of the back cover 120, thereby allowing the millimeter-wave electromagnetic wave signal to be entirely transmitted/transmitted from the first portion B1, or at least to be mostly transmitted from the first portion B1, while keeping the back cover 120 thin.

Fig. 7 to fig. 10 are also shown, which are antenna radiation patterns of millimeter wave electromagnetic wave signals under the four conditions of the rear cover in the embodiment of the present application, respectively. Specifically, fig. 7 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal in a case one, namely, in a free space (without a rear cover above the millimeter wave antenna module). Fig. 8 shows a second case, namely, an antenna radiation pattern of a millimeter wave electromagnetic wave signal with a dielectric constant equal to 28 and a thickness T equal to 0.7mm, where a rear cover is disposed above the millimeter wave antenna module. Fig. 9 shows the third case, that is, the antenna radiation pattern of the millimeter wave electromagnetic wave signal with the dielectric constant equal to 28 and the thickness T equal to 1mm is provided above the millimeter wave antenna module. Fig. 10 shows an antenna radiation pattern of a millimeter wave electromagnetic wave signal in a fourth case where a rear cover is disposed above the millimeter wave antenna module, the dielectric constant of the rear cover is 50, and the thickness T is 0.7 mm.

Similarly, a millimeter wave electromagnetic wave signal with a frequency of 28GHz is used as a test signal, and as shown in the antenna radiation pattern of the millimeter wave electromagnetic wave signal in each case shown in fig. 7 to 10, the gain effect under a plurality of directional beams is shown, in which the millimeter wave electromagnetic wave signal scans within a range of plus or minus 45 °, and 0 °, 30 °, and 45 ° are selected as examples in the antenna radiation pattern of the millimeter wave electromagnetic wave signal in each case shown in fig. 7 to 10. In the embodiment of the present invention, the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 may be a projection range of a scanning beam for scanning the millimeter wave electromagnetic wave signal within a range of plus or minus 45 °.

In fig. 7 to 10, the dark and large part is the main lobe M1, and the relatively small part beside it is the side lobe S1.

As shown in fig. 7, in the case of the free space, without the back cover above the millimeter wave antenna module, the main lobe M1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is mainly concentrated in the 0 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 0 ° direction, the 0 ° beam loss of the millimeter wave electromagnetic wave signal is small, and the gain is large, and is approximately 11.70 db. The main lobe M1 of the 30 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 30 ° direction, while the side lobe S1 is small, and the radiation energy is mainly concentrated in the main lobe M1 in the 30 ° direction, at this time, the 30 ° beam loss of the millimeter wave electromagnetic wave signal is also small, and the gain is large, and is approximately 10.60. As shown in fig. 7, the main lobe M1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 45 ° direction, and the side lobe S1 is small, and when the radiation energy is mainly concentrated in the main lobe M1 in the 45 ° direction, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is also small, and the gain is also large, and is approximately 9.804 db.

Therefore, it can be seen from the antenna radiation patterns of the directional beams that the return loss of the millimeter wave electromagnetic wave signal is very low in the free space, i.e., the case where there is no back cover above the millimeter wave antenna module.

As shown in fig. 8, in the case where there is a rear cover above the millimeter wave antenna module, and the dielectric constant is 28 and the thickness T is 0.7mm, the thickness T of the case two is 0.7mm as described above, and the dielectric constant of the case two is 0.35 of the dielectric wavelength 2mm when 28, but not 1/2 of the dielectric wavelength. As can be seen from fig. 8, the side lobe S1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is large, and at this time, the 0 ° beam loss of the millimeter wave electromagnetic wave signal is large, and more beams are reflected, and at this time, the gain is small, and is only approximately 1.860 db. The side lobe S1 of the 30 ° beam of the millimeter wave electromagnetic wave signal is also large, and at this time, the 30 ° beam loss of the millimeter wave electromagnetic wave signal is large, and a large number of beams are reflected, and at this time, the gain is small, and is approximately only 2.101 db. As shown in fig. 8, the side lobe S1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also large, and at this time, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is large, and many beams are reflected, and at this time, the gain is small, and is substantially only 2.606 db. As can be seen from fig. 8, since the side lobe S1 of the 0 ° beam, the side lobe S1 of the 30 ° beam, and the side lobe S1 of the 45 ° beam are all large and substantially the same as the main lobe M1, the gain is substantially the gain of the side lobe S1 and most of the gain causes a beam that should be radiated in the 0 ° direction, a 30 ° beam that should be radiated in the 30 ° direction, and a 45 ° beam that should be radiated in the 45 ° direction, and forms a scattered beam, and radiation energy is scattered in the main lobe M1 and the side lobe S1, resulting in low efficiency.

Therefore, it can be seen from the antenna radiation patterns of the directional beams that there is a back cover above the millimeter wave antenna module, the dielectric constant is 28, and the thickness T is 0.7mm, at this time, since the thickness of the back cover is not 1/2 of the dielectric wavelength, the return loss of the millimeter wave electromagnetic wave signal is high, that is, more millimeter wave electromagnetic wave signals are reflected back by the back cover, resulting in a small gain.

As shown in fig. 9, in the case of a millimeter wave electromagnetic wave signal with a dielectric constant equal to 28 and a thickness T equal to 1mm, the main lobe M1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is mainly concentrated in the 0 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 0 ° direction, the 0 ° beam loss of the millimeter wave electromagnetic wave signal is small, the gain is large, approximately 9.811db, and the effect of approximately full transmission of the 0 ° beam is achieved. The main lobe M1 of the 30 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 30 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 30 ° direction, the 30 ° beam loss of the millimeter wave electromagnetic wave signal is also small, the gain is also large, approximately 10.25db, and the effect of approximately full transmission of the 30 ° beam is achieved. As shown in fig. 9, the main lobe M1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 45 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 45 ° direction, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is also small, the gain is also large, and is approximately 10.11db, so that the effect of approximately full transmission of the 45 ° beam is achieved.

Therefore, it can be seen from the antenna radiation patterns of the directional beams that the return loss of the millimeter wave electromagnetic wave signal is very low and the gain is also very high in the case of a millimeter wave electromagnetic wave signal having a back cover above the millimeter wave antenna module, a dielectric constant equal to 28, and a thickness T equal to 1 mm.

As shown in fig. 10, under the condition that there is a back cover above the millimeter wave antenna module, and the dielectric constant is equal to 50, and the thickness T is equal to 0.7mm, the main lobe M1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is mainly concentrated in the 0 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 0 ° direction, the 0 ° beam loss of the millimeter wave electromagnetic wave signal is small, the gain is large, and is approximately 8.336db, and the effect of approximately full transmission of the 0 ° beam is achieved. The main lobe M1 of the 30 DEG wave beam of the millimeter wave electromagnetic wave signal is mainly concentrated in the 30 DEG direction, the side lobe S1 is small, the radiation energy is mainly concentrated in the main lobe M1 in the 30 DEG direction, the 30 DEG wave beam loss of the millimeter wave electromagnetic wave signal is small, the gain is large and is about 8.855db, and the effect of approximate full transmission of the 30 DEG wave beam is achieved. As shown in fig. 10, the main lobe M1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 45 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 45 ° direction, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is also small, the gain is large, and is about 8.308db, so that the effect of approximately full transmission of the 45 ° beam is achieved.

Therefore, it can be seen from the antenna radiation patterns of the directional beams that the return loss and the gain of the millimeter wave electromagnetic wave signal are also low under the condition that the rear cover is arranged above the millimeter wave antenna module, the dielectric constant is equal to 50, and the thickness T is equal to 0.7 mm.

Therefore, it can be seen that when the rear cover is arranged above the millimeter wave antenna module, the thickness of the rear cover is matched with the dielectric constant to meet the requirement that the thickness is equal to 1/2 of the medium wavelength, so that the maximum gain of millimeter wave electromagnetic wave signals can be realized, the reflection is very small, and the effect of approximate total transmission is achieved.

Fig. 11 is a schematic cross-sectional view illustrating a partial structure of an electronic device 1000 according to another embodiment of the present application. The rear cover 120 includes a first portion B1 and a second portion B2 arranged along a predetermined direction, the predetermined direction is a thickness direction of the rear cover 120, the first portion B1 is a dielectric matching layer 120a, the second portion B2 is a rear cover body 120B, and the dielectric matching layer 120a is stacked on one side of the rear cover body 120B in the thickness direction.

That is, in another embodiment, the back cover 120 achieves the dielectric constant of the first part B1 different from that of the second part B2 by adding the dielectric matching layer 120a to one side of the back cover body 120B.

Wherein, the rear cover body 120b can be a rear cover before modification. By stacking the first part B1, which is the dielectric matching layer 120a, on the side of the second part B2, which is the back cover body, the dielectric matching layer 120B can be added to the original back cover to realize total transmission of the millimeter wave electromagnetic wave signals, and the processing and manufacturing are easy.

In the present embodiment, the dielectric matching layer 120a is disposed on a side of the back cover body 120b facing the circuit board 300. That is, the dielectric matching layer 120a is disposed inside the back cover body 120 b. Thus, the outer surface of the rear cover 120, i.e., the surface of the side facing away from the display module 200, may maintain the integrity of the appearance.

The thickness and the dielectric constant of the dielectric matching layer 120a are related to the thickness of the back cover body 120b and the dielectric constant of the back cover body 120b, that is, the thickness and the dielectric constant of the dielectric matching layer 120a can be obtained according to the thickness of the back cover body 120b and the dielectric constant of the back cover body 120 b.

According to the multilayer dielectric theory, the back cover body 120b and the dielectric matching layer 120a can be regarded as a single layer of dielectric satisfying a half wavelength, thereby realizing full transmission of energy of the millimeter wave electromagnetic wave signal.

Specifically, the thickness T2 and the dielectric constant ∈ 2 of the dielectric matching layer 120a satisfy the second formula: t1 · (∈ 1) + T2 · (∈ 2) ═ λ 0/2, where T1 is the thickness of the back cover body 120b, ∈ 1 is the dielectric constant of the back cover body 120b, T2 is the thickness of the dielectric matching layer 120a, ∈ 1 is the dielectric constant of the dielectric matching layer 120a, and λ 0 is the wavelength of the millimeter-wave electromagnetic wave signal when propagating in the free space (i.e., air).

For example, taking a millimeter wave electromagnetic wave signal having a frequency of 28GHz as an example, when the dielectric constant ∈ 1 of the rear cover body 120b is 28 and the thickness T1 is 0.5mm, and the wavelength λ 0 ═ ν/f, the wavelength of the millimeter wave electromagnetic wave signal having a frequency of 28GHz when propagating in free space is 10.7mm, and the calculation formula is based on the wavelength in the medium (medium wavelength): when λ r is λ 0/sqrt (∈), it is understood that when the dielectric constant ∈ 1 of the back cover body 120b is 28, the dielectric wavelength at which the millimeter wave electromagnetic wave signal propagates through the back cover body 120b is 2mm, and therefore, the thickness of the back cover body 120b is 1/4 dielectric wavelength. Then by selecting the dielectric matching layer 120a with a specific thickness and dielectric constant to realize that the thickness of the dielectric matching layer 120a also satisfies 1/4 dielectric wavelengths, the thickness of the structure that can be regarded as a single-layer dielectric, which is formed by the back cover body 120b and the dielectric matching layer 120a together, can be 1/2 dielectric wavelengths. For example, in some examples, the dielectric constant ∈ 2 of the dielectric matching layer 120a is 56, and the thickness T2 is 0.36mm, according to the calculation formula of the wavelength in the medium (medium wavelength): when λ r is λ 0/sqrt (∈), it is found that when the dielectric constant ∈ 2 of the dielectric matching layer 120a is 56, the medium wavelength at which the millimeter-wave electromagnetic wave signal propagates through the dielectric matching layer 120a is approximately 1.44mm, and therefore the dielectric matching layer 120a is also 1/4 of the medium wavelength corresponding to the dielectric matching layer 120 a.

For easier understanding, λ r ═ λ 0/sqrt (∈), that is, sqrt (∈) ═ λ 0/λ r, may be substituted into the above second formula: t1 · (∈ 1) + T2 · (∈ 2) ═ λ 0/2, yielding the third formula: (T1 × λ 0/λ r1) + (T2 × λ 0/λ r2) ═ λ 0/2, where λ r1 is the medium wavelength corresponding to the back cover body 120b, and λ r2 is the medium wavelength corresponding to the dielectric matching layer 120 a. It can be seen that when T1-1/4 λ r1 and T2-1/4 λ r2, the third formula can be further modified to λ 0/4+ λ 0/4- λ 0/2.

Therefore, when the thickness T2 and the dielectric constant ∈ 2 of the dielectric matching layer 120a satisfy the second formula: t1 · sqrt (∈ 1) + T2 · sqrt (∈ 2) ═ λ 0/2, so that the thickness of the structure, which can be regarded as a single-layer medium, formed by the back cover body 120b and the dielectric matching layer 120a together is 1/2 medium wavelengths, thereby effectively reducing the return loss, and realizing full transmission or at least most transmission of the energy of the millimeter wave electromagnetic wave signal.

As shown in fig. 11, the dielectric matching layer 120a is disposed on a partial region of one side of the back cover body 120 b. Specifically, the dielectric matching layer 120a is disposed in a region of the back cover body 120b facing the circuit board 300 and corresponding to the millimeter wave antenna module 400. The dielectric matching layer 120a is disposed in the area of the rear cover body 120b facing the millimeter wave antenna module 400 on the circuit board 300 side, which means: the projection of the millimeter wave antenna module 400 on the rear cover 120 is located in the dielectric matching layer 120a of the rear cover 120, or the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the dielectric matching layer 120 a.

That is, in some embodiments, the projection of millimeter-wave antenna module 400 on back cover 120 is located in dielectric matching layer 120a of back cover 120, and the area of dielectric matching layer 120a may be greater than or equal to the area of the projection of millimeter-wave antenna module 400 on back cover 120. Alternatively, the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the dielectric matching layer 120a, wherein the projection range of the beam W1 of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 on the rear cover 120 is located in the dielectric matching layer 120a, and the beam W1 of most of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module 400 passes through the first portion B1. The size of the area of the dielectric matching layer 120a may be specifically determined according to an area of the rear cover 120 through which most of the millimeter wave electromagnetic wave signals transmitted by the millimeter wave antenna module 400 pass.

Referring also to fig. 12, a schematic diagram of a millimeter wave electromagnetic wave signal transmitted from the first portion B1 of the back cover 120 shown in fig. 11 through the back cover 120 is illustrated.

As described above, when the dielectric matching layer 120a, that is, the first portion B1, is disposed on the side of the rear cover body 120B facing the circuit board 300, according to the multi-layer dielectric theory, the rear cover body 120B and the dielectric matching layer 120a can be regarded as a single-layer dielectric satisfying a half wavelength, thereby realizing full transmission of energy of the millimeter wave electromagnetic wave signal W1. As shown in fig. 12, the phase of the millimeter wave electromagnetic wave signal W1 when entering the dielectric matching layer 120a differs from the phase after passing through the first section B1 and the rear cover body 120B and having passed through the rear cover body 120B by half a wavelength, that is, by pi (180 °). Therefore, as shown in fig. 12, the amplitude of the millimeter wave electromagnetic wave signal W1 when entering the dielectric matching layer 120a and the absolute value of the amplitude when exiting the rear cover body 120b are almost equal, and thus, there is almost no energy loss, and full transmission or most transmission of the millimeter wave electromagnetic wave signal W1 is achieved.

Fig. 13 is another cross-sectional view of a schematic partial structure of an electronic device 1000 according to another embodiment of the present application. In another example, the dielectric matching layer 120a may also completely cover the side of the back cover body 120b facing the circuit board, i.e., completely cover the inner surface of the back cover body 120 b. Further, the size and shape of the dielectric matching layer 120a are the same as those of the inner surface of the back cover body 120 b.

The schematic top view of the back cover 120 shown in fig. 2 is only a schematic diagram of a partial region where the dielectric matching layer 120a is disposed on the back cover body 120 b. Obviously, when the dielectric matching layer 120a completely covers the side of the rear cover body 120B facing the circuit board, the first portion B1 is coincident with the second portion B2 as seen from a schematic top view of the outer surface side of the rear cover 120.

Referring to fig. 14 to 16 together, fig. 14 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal without a back cover in the embodiment of the present application. Fig. 15 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal in the case where the rear cover does not include the dielectric matching layer in the embodiment of the present application. Fig. 16 is an antenna radiation pattern of a millimeter wave electromagnetic wave signal in the case where the back cover includes the dielectric matching layer in the embodiment of the present application.

Similarly, taking a millimeter wave electromagnetic wave signal with a frequency of 28GHz as a test signal, as an antenna radiation pattern of the millimeter wave electromagnetic wave signal in each case shown in fig. 14 to 16, a gain effect under a plurality of directional beams is shown, wherein the millimeter wave electromagnetic wave signal scans within a range of plus or minus 45 °, and 0 °, 30 °, and 45 ° are selected as examples in the antenna radiation pattern of the millimeter wave electromagnetic wave signal in each case shown in fig. 14 to 16 for explanation.

In fig. 14 to 16, the dark and large part is a main lobe M1, and the relatively small part beside it is a side lobe S1.

As shown in fig. 14, in the case of no back cover, the main lobe M1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is mainly concentrated in the 0 ° direction, and the side lobe S1 is small, at which time, the radiation energy is mainly concentrated in the main lobe M1 in the 0 ° direction, and the 0 ° beam loss of the millimeter wave electromagnetic wave signal is small, and the gain is large, approximately 11.70 db. The main lobe M1 of the 30 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 30 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 30 ° direction, and the 30 ° beam loss of the millimeter wave electromagnetic wave signal is also small, and the gain is large, and is approximately 10.90 db. As shown in fig. 14, the main lobe M1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 45 ° direction, and the side lobe S1 is small, at which time the radiation energy is mainly concentrated in the main lobe M1 in the 45 ° direction, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is also small, and the gain is large, approximately 9.804 db.

Therefore, it can be seen from the antenna radiation patterns of the directional beams that the return loss of the millimeter wave electromagnetic wave signal is very low in the free space, i.e., the case where there is no back cover above the millimeter wave antenna module. Since the millimeter wave electromagnetic wave signals used are all millimeter wave electromagnetic wave signals with a frequency of 28GHz, the antenna radiation pattern of the millimeter wave electromagnetic wave signals without the back cover shown in fig. 14 is substantially the same as the antenna radiation pattern in the free space, without the back cover above the millimeter wave antenna module shown in fig. 7.

As shown in fig. 15, although there is a rear cover above the millimeter wave antenna module, the rear cover does not include a dielectric matching layer, and when the dielectric constant of the rear cover is equal to 28 and the thickness T is 0.5mm, as described above, the thickness 0.5mm is 1/4 of 2mm of the dielectric wavelength when the dielectric constant of the rear cover body is equal to 28, and is not 1/2 of the dielectric wavelength. As can be seen from fig. 15, the side lobe S1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is larger, and at this time, the 0 ° beam of the millimeter wave electromagnetic wave signal is more lost, and more beams are reflected, and at this time, the gain is small, and is only about 2.274 db. The side lobe S1 of the 30 ° wave beam of the millimeter wave electromagnetic wave signal is also large, and at this time, the 30 ° wave beam of the millimeter wave electromagnetic wave signal has a certain loss, and a certain wave beam is reflected, and at this time, the gain is not large, and is about 6.748 db. On the other hand, as shown in fig. 15, the side lobe S1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also large, and at this time, the gain is 9.510db, but as can be seen from fig. 15, the side lobe S1 of the 30 ° beam and the side lobe S1 of the 45 ° beam are both large and are substantially the same as the main lobe M1, and therefore, the gain is actually and mostly the gain of the side lobe S1, resulting in a 30 ° beam that should be radiated in the 30 ° direction and a 45 ° beam that should be radiated in the 45 ° direction, forming a scattered beam, and resulting in low efficiency. As can be seen from fig. 15, the side lobe S1 of the 0 ° beam is also much, and a scattered beam is also formed, resulting in excessive dispersion of radiation energy at the side lobe S1, resulting in low efficiency.

Therefore, it can be seen from the antenna radiation patterns of the beams in multiple directions that, in the case where the back cover is disposed above the millimeter wave antenna module but does not include the dielectric matching layer, since the thickness of the back cover is not 1/2 of the dielectric wavelength, the return loss of the millimeter wave electromagnetic wave signal is high in the beam in the 0 ° direction, that is, a large amount of millimeter wave electromagnetic wave signal is reflected by the back cover, and the side lobe S1 of the 0 ° beam is large, so that the 0 ° beam that should be radiated in the 0 ° direction is formed, and a scattered beam is formed, resulting in low efficiency. Similarly, since the side lobe S1 of the 30 ° beam and the side lobe S1 of the 45 ° beam are both large and substantially the same as the main lobe M1, the gain is substantially the gain of the side lobe S1, and thus the 30 ° beam that should be radiated in the 30 ° direction and the 45 ° beam that should be radiated in the 45 ° direction are caused, and a scattered beam is formed, resulting in low efficiency.

As shown in fig. 16, the back cover 120 above the millimeter wave antenna module includes a dielectric matching layer 120a, and the thickness T2 and the dielectric constant ∈ 2 of the dielectric matching layer 120a satisfy the second formula: when T1 × (sqrt (∈ 1) + T2 × (∈ 2) ═ λ 0/2, the main lobe M1 of the 0 ° beam of the millimeter wave electromagnetic wave signal is mainly focused in the 0 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly focused on the main lobe M1 in the 0 ° direction, the 0 ° beam loss of the millimeter wave electromagnetic wave signal is small, the gain is large, and is approximately 9.107db, and the effect of approximately full transmission of the 0 ° beam is achieved. As shown in fig. 16, the main lobe M1 of the 30 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 30 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 30 ° direction, the 30 ° beam loss of the millimeter wave electromagnetic wave signal is also small, the gain is large, and approximately 7.429db, and the effect of approximately full transmission of the 30 ° beam is achieved. As shown in fig. 16, the main lobe M1 of the 45 ° beam of the millimeter wave electromagnetic wave signal is also mainly concentrated in the 45 ° direction, and the side lobe S1 is small, at this time, the radiation energy is mainly concentrated in the main lobe M1 in the 45 ° direction, the 45 ° beam loss of the millimeter wave electromagnetic wave signal is small, the gain is large, and is about 6.426db, so that the effect of approximately full transmission of the 45 ° beam is achieved. As shown in fig. 16, the main lobes of the electromagnetic wave beams in a plurality of directions are concentrated, the side lobes are small, and the efficiency is high.

Therefore, as can also be seen from the antenna radiation patterns of the multiple directional beams, the rear cover 120 above the millimeter wave antenna module includes the dielectric matching layer 120a, and the thickness T2 and the dielectric constant ∈ 2 of the dielectric matching layer 120a satisfy the second formula: when T1 · (∈ 1) + T2 · (∈ 2) · λ 0/2, the return loss of the millimeter-wave electromagnetic wave signal is low.

When the rear cover 120 includes the rear cover body 120b and the dielectric matching layer 120a on the side of the rear cover body 120b, the dielectric constant (i.e., the first dielectric constant) of the dielectric matching layer 120a may be greater than the dielectric constant (i.e., the second dielectric constant) of the rear cover body 120b, according to the foregoing analysis, when the transmission requirement of the millimeter wave electromagnetic wave signal is satisfied, the thickness of the dielectric matching layer 120a is inversely proportional to the dielectric constant, and therefore, the dielectric constant of the dielectric matching layer 120a is set to be larger, so that the thickness of the dielectric matching layer 120a is thinner than that of the rear cover body 120b, and therefore, the overall thickness of the rear cover 120 is not excessively increased, and the overall size of the whole device is not affected.

Obviously, in other embodiments, the dielectric constant (i.e., the first dielectric constant) of the dielectric matching layer 120a may also be smaller than the dielectric constant (i.e., the second dielectric constant) of the back cover body 120b, so that the dielectric matching layer 120a is opposite. For example, for the back cover 120 with the back cover body 120b itself being thinner, the media matching layer 120a may be provided thicker, which may increase the overall strength of the back cover 120.

The first portion B1 and the second portion B2 of the rear cover 120 are made of different non-metal materials, for example, the second portion B2 of the rear cover 120 may be made of a ceramic material, and the first portion B1 of the rear cover 120 may be made of other non-metal materials.

Fig. 17 shows an antenna radiation pattern of a millimeter wave electromagnetic wave signal when the rear cover includes a dielectric matching layer with a specific dielectric constant and thickness according to an embodiment of the present application.

Specifically, fig. 17 is a schematic diagram of the 0 ° radiation direction of the millimeter wave electromagnetic wave signal obtained by performing simulation when the millimeter wave electromagnetic wave signal having the frequency of 28GHz is used as the test signal, the rear cover 120 includes the dielectric matching layer 120a, the dielectric constant ∈ 2 of the dielectric matching layer 120a is 56, the thickness T2 is 0.36mm, the dielectric constant of the rear cover body 120b is 28, and the thickness T1 is 0.5 mm.

When the dielectric constant of the back cover body 120b is equal to 28, the thickness T1 is 0.5mm, the dielectric constant e 2 of the dielectric matching layer 120a is 56, and the thickness T2 is 0.36mm, the formula is satisfied: t1 · (∈ 1) + T2 · (∈ 2) ═ λ 0/2. As shown in fig. 17, when the dielectric constant ∈ 2 of the dielectric matching layer 120a is 56 and the thickness T2 is 0.36mm, the main lobe M1 of the 0 ° beam of the millimeter-wave electromagnetic wave signal is mainly concentrated in the 0 ° direction, and the side lobe S1 is small, at this time, the 0 ° beam loss of the millimeter-wave electromagnetic wave signal is small, the gain is large, and is approximately 10.14db, and the effect of approximately full transmission of the 0 ° beam is achieved.

Obviously, similar to the foregoing fig. 16, when the dielectric constant ∈ 2 of the dielectric matching layer 120a is 56, and the thickness T2 is 0.36mm, the gains of beams in other directions of the millimeter-wave electromagnetic wave signal are all large, and are not described again.

It can be seen that setting the dielectric constant of the dielectric matching layer 120a to a relatively large value of 56 still satisfies the effect of approximately full transmission of the millimeter wave electromagnetic wave signals, and the thickness of the dielectric matching layer 120a can be made very thin, without increasing the overall thickness of the rear cover 120 too much and without affecting the overall size.

Please refer to fig. 6 and fig. 18. Fig. 18 is a schematic cross-sectional view of a millimeter-wave antenna module 400 in an embodiment of the present application, and particularly, a schematic cross-sectional view of the millimeter-wave antenna module 400 shown in fig. 6.

As mentioned above, in one embodiment, the millimeter-wave antenna module 400 includes a plurality of antennas 401, and the plurality of antennas 401 form an antenna array. As shown in fig. 5 and 16, the millimeter wave antenna module 400 further includes an antenna substrate 402, and a plurality of antennas 401 are disposed on the antenna substrate 402 and are arranged in a row at intervals. The antenna substrate 402 is an insulating dielectric substrate.

As shown in fig. 18, antenna substrate 402 includes a first surface 402a and a second surface 402b, where when millimeter-wave antenna module 400 is disposed on circuit board 300, first surface 402a is a surface facing back cover 120, and second surface 402b is a surface facing away from back cover 120. Each antenna 401 includes an upper metal sheet 401a and a lower metal sheet 401b, wherein the upper metal sheet 401a and the lower metal sheet 401b are disposed at an interval, and projections of the upper metal sheet 401a and the lower metal sheet 401b in a direction from the first surface 402a to the second surface 402b are substantially overlapped. As shown in fig. 15, an upper metal piece 401a is provided in the antenna substrate 402 at a position close to the first surface 402a, and a lower metal piece 401b is provided in the antenna substrate 402 at a position close to the second surface 402 b. The upper metal sheet 401a and the lower metal sheet 401b are patch-shaped and are disposed substantially parallel to the first face 402a and the second face 402b in the antenna substrate 402, that is, substantially parallel to the inner surface of the rear cover 120 or the surface of the circuit board 300.

The lower metal sheet 401b is provided with a feed point K1, the lower metal sheet 401b is connected to a feed source (not shown) through a feed point K1, and the lower metal sheet 401b and the upper metal sheet 401a are spatially coupled to transmit a feed signal to the upper metal sheet 401a, so that a millimeter wave electromagnetic wave signal is generated by the upper metal sheet 401a and the lower metal sheet 401b, and the millimeter wave electromagnetic wave signal is radiated toward the rear cover 120 through the upper metal sheet 401 a.

Here, the structure of each antenna 401 is the same, so the above description is given by taking only one antenna 401 as an example.

Each antenna 401 is a patch antenna formed by an upper metal sheet 401a and a lower metal sheet 401b, and may be formed in the antenna substrate 402 by a laser process or the like. Alternatively, each antenna 401 may be an FPC (flexible printed circuit) antenna disposed on the antenna substrate 402. The FPC antenna refers to a metal antenna pattern formed on an FPC, and the FPC antenna may be fixed to the antenna substrate 402 by bonding, embedding, welding, or the like.

The millimeter-wave antenna module 400 may be carried on a surface of the circuit board 300 facing the rear cover 120. Or, a groove penetrating or not penetrating the circuit board 300 may be formed on the surface of the circuit board 300 facing the rear cover 120, and the millimeter wave antenna module 400 is accommodated in the groove, thereby facilitating reduction of the thickness of the whole device.

The structure of the millimeter wave antenna module 400 may be the structure of the millimeter wave antenna module 400 included in the electronic device 1000, or may be the structure of the millimeter wave antenna module used in the simulation.

In other embodiments, the millimeter-wave antenna module 400 may have other structures, for example, the millimeter-wave antenna module only includes one or more antennas 401 and does not include the antenna substrate 402, and the antenna 401 has a structure different from the above-mentioned structure, for example, a PIFA (planar inverted F antenna), and the antenna 401 is directly formed on the circuit board 300.

Therefore, in the present application, by providing the first portion B1, which is a portion with a specific dielectric constant, in the rear cover 120, at least the reflection of the millimeter wave electromagnetic wave signal in the first portion B1 of the rear cover 120 can be effectively reduced, the gain of the millimeter wave electromagnetic wave signal can be effectively improved, and the radiation performance of the antenna can be improved.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application; the embodiments and features of the embodiments of the present application may be combined with each other without conflict. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (11)

1. An electronic device for improving antenna radiation performance, the electronic device comprising:

the rear cover comprises a first part and a second part which are arranged along a preset direction, wherein the dielectric constant of the first part is different from that of the second part;

a circuit board; and

the millimeter wave antenna module is arranged on one side, facing the rear cover, of the circuit board and corresponds to the first part, and is used for transmitting and receiving millimeter wave electromagnetic wave signals;

the projection of the millimeter wave antenna module on the rear cover is located in the first part of the rear cover, or the projection range of the beam of the millimeter wave electromagnetic wave signal emitted by the millimeter wave antenna module on the rear cover is located in the first part of the rear cover.

2. The electronic device according to claim 1, wherein the predetermined direction is a direction perpendicular to a thickness direction of the rear cover, the first portion is located in a first region of the rear cover, the second portion is located in a second region of the rear cover other than the first region, and the first region and the second region do not overlap in the thickness direction.

3. The electronic device of claim 2, wherein the dielectric constant of the first portion is a first dielectric constant that satisfies a half-wavelength of the medium for the millimeter-wave electromagnetic wave signals to pass through the first portion of the back cover equal to the thickness of the first portion of the back cover.

4. The electronic device of claim 3, wherein the first dielectric constant satisfies the formula: t × sqrt (∈) ═ λ 0/2, where T is the thickness of the first portion of the back cover, ∈ is the first dielectric constant, and λ 0 is the wavelength of the millimeter-wave electromagnetic wave signal when propagating in air.

5. The electronic device of claim 3, wherein a thickness of the first portion of the back cover is the same as a thickness of the second portion of the back cover.

6. The electronic device according to claim 1, wherein the predetermined direction is a thickness direction of the rear cover, the first portion is a dielectric matching layer, the second portion is a rear cover body, and the dielectric matching layer is stacked on one side of the rear cover body in the thickness direction.

7. The electronic device of claim 6, wherein the dielectric matching layer is disposed on a side of the rear cover body facing the circuit board.

8. The electronic device of claim 6, wherein a thickness and a dielectric constant of the dielectric matching layer are related to a thickness and a dielectric constant of the back cover body.

9. The electronic device of claim 8, wherein the dielectric matching layer has a thickness T2 that satisfies the formula: t1 · (∈ 1) + T2 · sqrt (∈ 2) ═ λ 0/2, where T1 is the thickness of the rear cover body, ∈ 1 is the dielectric constant of the rear cover body, T2 is the thickness of the dielectric matching layer, ∈ 2 is the dielectric constant of the dielectric matching layer, and λ 0 is the wavelength of the millimeter-wave electromagnetic wave signal when propagating in the air.

10. The electronic device of claim 8, wherein a dielectric constant of the dielectric matching layer is greater than a dielectric constant of the back cover body.

11. The electronic device according to claim 6, wherein the dielectric matching layer is stacked on a partial region or a whole region on one side of the rear cover body.

Images