Patent Publication Number: US-2022216615-A1

Title: Antenna apparatus and electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation of International Application No. PCT/CN2020/122464, filed Oct. 21, 2020, which claims priority to Chinese Patent Application No. 201911011137.6, filed Oct. 22, 2019, the entire disclosures of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This disclosure relates to the field of electronic devices, and in particular to an antenna apparatus and an electronic device. 
     BACKGROUND 
     With development of mobile communication technology, the traditional 4th-generation (4G) mobile communication can no longer meet people&#39;s requirements. The 5th-generation (5G) mobile communication is favored by users for its high communication speed. For example, a data transmission speed in the 5G mobile communication is hundreds of times faster than that in the 4G mobile communication. The 5G mobile communication is mainly implemented via millimeter wave (mmWave) signals. However, when an mmWave antenna is applied to an electronic device, the mmWave antenna is usually disposed in an accommodation space in the electronic device, and an mmWave signal radiated out through the electronic device has a poor gain, resulting in poor communication performance of 5G mmWave signals. 
     SUMMARY 
     An antenna apparatus and an electronic device are provided in the present disclosure. 
     In a first aspect, an antenna apparatus is provided in the present disclosure. The antenna apparatus includes an antenna module and an antenna radome. The antenna module is configured to receive/emit a first radio frequency (RF) signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range, where the first preset frequency band is lower than the second preset frequency band, and the first preset direction range and the second preset direction range have an overlapped region. The antenna radome is spaced apart from the antenna module and includes a substrate and a resonant structure carried on the substrate, where the resonant structure is at least partially located in the overlapped region, and the resonant structure at least has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     In a second aspect, an electronic device is provided in the present disclosure. The electronic device includes a controller and the antenna apparatus in the first aspect of the present disclosure. The antenna apparatus is electrically connected with the controller, and the antenna module in the antenna apparatus is configured to emit a first RF signal and a second RF signal under control of the controller. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to describe technical solutions of implementations of the present disclosure more clearly, the following will give a brief introduction to the accompanying drawings used for describing the implementations. Apparently, the accompanying drawings hereinafter described are merely some implementations of the present disclosure. Based on these drawings, those of ordinary skill in the art can also obtain other drawings without creative effort. 
         FIG. 1  is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. 
         FIG. 2  is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. 
         FIG. 3  is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. 
         FIG. 4  is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. 
         FIG. 5  is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. 
         FIG. 6  is a cross-sectional view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 7  is a schematic view of an arrangement of resonant structures provided in an implementation of the present disclosure. 
         FIG. 8  is a schematic view of an arrangement of resonant structures provided in an implementation of the present disclosure. 
         FIG. 9  is a cross-sectional view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 10  is a top view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 11  is a bottom view of the resonant structure illustrated in  FIG. 10 . 
         FIG. 12  is a cross-sectional view taken along line I-I in  FIG. 10 . 
         FIG. 13  is a top view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 14  is a bottom view of the resonant structure illustrated in  FIG. 13 . 
         FIG. 15  is a cross-sectional view taken along line II-II in  FIG. 13 . 
         FIG. 16  is a top view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 17  is a bottom view of the resonant structure illustrated in  FIG. 16 . 
         FIG. 18  is a cross-sectional view taken along line III-III in  FIG. 16 . 
         FIG. 19  is a top view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 20  is a bottom view of the resonant structure illustrated in  FIG. 19 . 
         FIG. 21  is a cross-sectional view taken along line IV-IV in  FIG. 19 . 
         FIG. 22  is a cross-sectional view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 23  is a schematic view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 24  is a schematic view of a resonant structure provided in an implementation of the present disclosure. 
         FIG. 25  is a schematic view of a resonant structure provided in an implementation of the present disclosure. 
         FIGS. 26-33  are schematic structural views of resonant units in a resonant structure. 
         FIG. 34  illustrates reflection coefficient S 11  curves corresponding to substrates with different dielectric constants. 
         FIG. 35  illustrates reflection phases corresponding to a radio frequency (RF) signal of 28 GHz in reflection phase curves corresponding to substrates with different dielectric constants. 
         FIG. 36  illustrates the reflection phase corresponding to an RF signal of 39 GHz in the curve of reflection phase corresponding to substrates with different dielectric constants. 
         FIG. 37  is a schematic diagram illustrating curves of reflection coefficient S 11  and transmission coefficient S 12  of an antenna radome provided in the present disclosure. 
         FIG. 38  is a schematic diagram illustrating a reflection phase curve of an antenna radome provided in the present disclosure. 
         FIG. 39  is a directional pattern at 28 GHz and 39 GHz of an antenna radome provided in the present disclosure. 
         FIG. 40  is a circuit block diagram of an electronic device provided in an implementation of the present disclosure. 
         FIG. 41  is a schematic structural view of an electronic device provided in an implementation of the present disclosure. 
         FIG. 42  is a schematic structural view of an electronic device provided in an implementation of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In a first aspect, an antenna apparatus is provided in implementations of the present disclosure. The antenna apparatus includes an antenna module and an antenna radome. The antenna module is configured to receive/emit a first radio frequency (RF) signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range, where the first preset frequency band is lower than the second preset frequency band, and the first preset direction range and the second preset direction range have an overlapped region. The antenna radome is spaced apart from the antenna module and includes a substrate and a resonant structure carried on the substrate, where the resonant structure is at least partially located in the overlapped region. The resonant structure at least has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     In an implementation, the resonant structure at least satisfies: 
     
       
         
           
             
               
                 
                   
                     ( 
                     
                       
                         
                           ϕ 
                           
                             R 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                         
                         π 
                       
                       - 
                       1 
                     
                     ) 
                   
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     4 
                   
                 
                 + 
                 
                   N 
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     2 
                   
                 
               
               = 
               
                 
                   
                     ( 
                     
                       
                         
                           ϕ 
                           
                             R 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             2 
                           
                         
                         π 
                       
                       - 
                       1 
                     
                     ) 
                   
                   ⁢ 
                   
                     
                       λ 
                       2 
                     
                     4 
                   
                 
                 + 
                 
                   N 
                   ⁢ 
                   
                     
                       λ 
                       2 
                     
                     2 
                   
                 
               
             
             , 
           
         
       
     
     where ϕ R1  represents a difference between a reflection phase and an incident phase brought by the resonant structure to the first RF signal, λ 1  represents a wavelength of the first RF signal in air, ϕ R2  represents a difference between a reflection phase and an incident phase brought by the resonant structure to the second RF signal, λ 2  represents a wavelength of the second RF signal in air, and Nis a positive integer. 
     In an implementation, the resonant structure includes a first sub-resonant structure and a second sub-resonant structure spaced apart from the first sub-resonant structure, the first sub-resonant structure has in-phase reflection characteristics to the first RF signal, and the second resonant structure has in-phase reflection characteristics to the second RF signal. 
     In an implementation, the resonant structure includes a first resonant layer and a second resonant layer stacked with the first resonant layer, the first resonant layer is farther away from the antenna module than the second resonant layer. The first resonant layer includes first resonant units arranged at regular intervals, the first resonant unit includes a first resonant patch, the second resonant layer includes second resonant units arranged at regular intervals, the second resonant unit includes a second resonant patch, the first resonant patch is opposite to the second resonant patch. An orthographic projection of the second resonant patch on a plane where the first resonant patch is located at least partially overlaps with a region where the first resonant patch is located, the first resonant patch and the second resonant patch are conductive patches, and the following is satisfied: L low_f ≤W low_f , where W low_f  represents a side length of the first resonant patch, L low_f  represents a side length of the second resonant patch, and the first sub-resonant structure at least includes the first resonant patch and the second resonant patch. 
     In an implementation, the resonant structure includes a first resonant layer and a second resonant layer stacked with the first resonant layer, the first resonant layer is farther away from the antenna module than the second resonant layer. The first resonant layer includes first resonant units arranged at regular intervals, the first resonant unit includes a first resonant patch, the second resonant layer includes second resonant units arranged at regular intervals, the second resonant unit includes a second resonant patch, the first resonant patch is opposite to the second resonant patch. An orthographic projection of the second resonant patch on a plane where the first resonant patch is located at least partially overlaps with a region where the first resonant patch is located, the first resonant patch is a conductive patch, the second resonant patch is a conductive patch and defines a first hollow structure penetrating two opposite surfaces of the second resonant patch, and the following is satisfied: L low_f ≥W low_f , where W low_f  represents a side length of the first resonant patch, L low_f  represents a side length of the second resonant patch, a difference between W low_f  and L low_f  increases as an area of the first hollow structure increases, and the first sub-resonant structure at least includes the first resonant patch and the second resonant patch. 
     In an implementation, the first resonant unit includes a third resonant patch spaced apart from the first resonant patch, a side length of the third resonant patch is less than the side length of the first resonant patch. The second resonant unit includes a fourth resonant patch spaced apart from the second resonant patch, a side length of the fourth resonant patch is less than the side length of the second resonant patch, the fourth resonant patch is opposite to the third resonant patch. An orthographic projection of the fourth resonant patch on a plane where the third resonant patch is located at least partially overlaps with a region where the third resonant patch is located, the third resonant patch and the fourth resonant patch are conductive patches, and the following is satisfied: L high_f ≤W high_f , where W high_f  represents the side length of the third resonant patch, L high_f  represents the side length of the fourth resonant patch, and the second sub-resonant structure at least includes the third resonant patch and the fourth resonant patch. 
     In an implementation, the first resonant unit includes a third resonant patch spaced apart from the first resonant patch, a side length of the third resonant patch is less than the side length of the first resonant patch. The second resonant unit includes a fourth resonant patch spaced apart from the second resonant patch, a side length of the fourth resonant patch is less than the side length of the second resonant patch. The fourth resonant patch is opposite to the third resonant patch, an orthographic projection of the fourth resonant patch on a plane where the third resonant patch is located at least partially overlaps with a region where the third resonant patch is located, the third resonant patch is a conductive patch, the fourth resonant patch is a conductive patch and defines a second hollow structure penetrating two opposite surfaces of the fourth resonant patch, and the following is satisfied: L high_f ≥W high_f , where W high_f  represents the side length of the third resonant patch, L high_f  represents the side length of the fourth resonant patch, a difference between L high_f  and W high_f  increases as an area of the second hollow structure increases, and the second sub-resonant structure at least includes the third resonant patch and the fourth resonant patch. 
     In an implementation, the first resonant unit further includes another first resonant patch and another third resonant patch, the two first resonant patches are diagonally arranged and spaced apart from each other, the side length of the third resonant patch is less than the side length of the first resonant patch, and the two third resonant patches are arranged diagonally and spaced apart from each other. 
     In an implementation, a center of the two first resonant patches as a whole coincides with a center of the two third resonant patches as a whole. 
     In an implementation, the second resonant unit further includes another second resonant patch and another fourth resonant patch, the two second resonant patches are diagonally arranged and spaced apart from each other, and the two fourth resonant patches are diagonally arranged and spaced apart from each other. 
     In an implementation, a center of the two second resonant patches as a whole coincides with a center of the two fourth resonant patches as a whole. 
     In an implementation, a center of the first resonant patch is electrically connected with a center of the second resonant patch via a conductive member. 
     In an implementation, the resonant structure includes multiple first conductive lines spaced apart from one another and multiple second conductive lines spaced apart from one another. The multiple first conductive lines are intersected with the multiple second conductive lines, and the multiple first conductive lines are electrically connected with the multiple second conductive lines at intersections. 
     In an implementation, the resonant structure includes multiple conductive grids arranged in arrays, each of the multiple conductive grids is enclosed by at least one conductive line, and two adjacent conductive grids at least partially share the conductive line. 
     In an implementation, a distance between of a radiation surface of the resonant structure facing the antenna module and a radiation surface of the antenna module satisfies: 
     
       
         
           
             
               h 
               = 
               
                 
                   
                     ( 
                     
                       
                         
                           ϕ 
                           
                             R 
                             ⁢ 
                             
                                 
                             
                             ⁢ 
                             1 
                           
                         
                         π 
                       
                       - 
                       1 
                     
                     ) 
                   
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     4 
                   
                 
                 + 
                 
                   N 
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     2 
                   
                 
               
             
             , 
           
         
       
     
     where h represents a length of a line segment of a center line of the radiation surface of the antenna module from the radiation surface of the antenna module to a surface of the resonant structure facing the antenna module, the center line is a straight line perpendicular to the radiation surface of the antenna module, ϕ R1  represents a difference between a reflection phase and an incident phase brought by the resonant structure to the first RF signal, λ 1  represents a wavelength of the first RF signal in air, and Nis a positive integer. 
     In an implementation, when ϕ R1 =0, a minimum distance h between the radiation surface of the resonant structure facing the antenna module and the radiation surface of the antenna module is equal to λ 1 /4. 
     In an implementation, a maximum value D max  of a directivity coefficient of the antenna module satisfies: 
     
       
         
           
             
               
                 D 
                 max 
               
               = 
               
                 
                   1 
                   + 
                   
                     R 
                     1 
                   
                 
                 
                   1 
                   - 
                   
                     R 
                     1 
                   
                 
               
             
             , 
           
         
       
     
     where R 1 =S 11   2 , and S 11  represents an amplitude of a reflection coefficient of the antenna radome to the first RF signal. 
     In an implementation, the preset frequency band at least includes a full frequency band of 3rd generation partnership project (3GPP) millimeter wave (mmWave). 
     In a second aspect, an electronic device is provided in implementations of the present disclosure. The electronic device includes a controller and the antenna apparatus provided in any of the implementations in the first aspect. The antenna apparatus is electrically connected with the controller, and the antenna module in the antenna apparatus is configured to emit a first RF signal and a second RF signal under control of the controller. 
     In an implementation, the electronic device includes a battery cover, and the substrate at least includes the battery cover. The resonant structure is directly disposed on an inner surface of the battery cover; or the resonant structure is attached to the inner surface of the battery cover via a carrier film; or the resonant structure is directly disposed on an outer surface of the battery cover; or the resonant structure is attached to the outer surface of the battery cover via a carrier film; or part of the resonant structure is disposed on the inner surface of the battery cover, and part of the resonant structure is disposed on the outer surface of the battery cover; or the resonant structure is partially embedded in the battery cover. 
     In an implementation, the electronic device further includes a screen. The substrate at least includes the screen, the screen includes a cover plate and a display module stacked with the cover plate, and the resonant structure is located between the cover plate and the display module. 
     In the implementations of the present disclosure, the antenna apparatus and the electronic device are provided to overcome a technical problem that traditional millimeter wave signals have poor communication performance. 
     Technical solutions of implementations of the present disclosure will be described clearly and completely with reference to accompanying drawings in the implementations of the present disclosure. Apparently, implementations described herein are merely some rather than all implementations of the present disclosure. Based on the implementations of the present disclosure, all other implementations obtained by those of ordinary skill in the art without creative effort shall fall within the protection scope of the present disclosure. 
     Reference is made to  FIG. 1 , which is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. An antenna apparatus  10  includes an antenna module  100  and an antenna radome  200 . The antenna module  100  is configured to receive/emit a first radio frequency (RF) signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range. The first preset frequency band is lower than the second preset frequency band, and the first preset direction range and the second preset direction range have an overlapped region. The antenna radome  200  is spaced apart from the antenna module  100  and includes a substrate  210  and a resonant structure  230  carried on the substrate  210 . The resonant structure  230  is at least partially located in the overlapped region. The resonant structure  230  at least has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. It can be understood, the resonant structure  230  at least has the in-phase reflection characteristics to the first RF signal and the in-phase reflection characteristics to the second RF signal, which means that the resonant structure  230  has in-phase reflection characteristics to the first RF signal and has in-phase reflection characteristics to the second RF signal, or means that in addition to having in-phase reflection characteristics to the first RF signal and the second RF signal, the resonant structure  230  also has in-phase reflection characteristics to other RF signals other than the first RF signal and the second RF signal (that is, the resonant structure  230  has in-phase reflection characteristics to multiple RF signals). 
     The first RF signal may be, but is not limited to, an RF signal in an mmWave frequency band or an RF signal in a terahertz (THz) frequency band. Currently, in the 5th generation (5G) wireless systems, according to the 3rd generation partnership project (3GPP) technical specification (TS) 38.101 protocol, 5G new radio (NR) mainly uses two frequency bands: a frequency range 1 (FR1) band and a frequency range 2 (FR2) band. The FR1 band has a frequency range of 450 megahertz (MHz)˜6 gigahertz (GHz), and is also known as the sub-6 GHz band. The FR2 band has a frequency range of 24.25 Ghz-52.6 Ghz, and belongs to the mmWave frequency band. The 3GPP Release 15 specifies that the present 5G mmWave frequency bands include: n257 (26.5˜29.5 Ghz), n258 (24.25˜27.5 Ghz), n261 (27.5˜28.35 Ghz), and n260 ( 37 ˜40 GHz). Correspondingly, the second RF signal may be, but is not limited to, an RF signal in an mmWave frequency band or an RF signal in a THz frequency band. In an implementation, the first preset frequency band of the first RF signal may be band n261, and the second preset frequency band of the second RF signal may be band n260. In other implementations, the first preset frequency band of the first RF signal may be band n260, and the second preset frequency band of the second RF signal may be band n261. Of course, the first preset frequency band and the second preset frequency band may also be other frequency bands, as long as the first preset frequency band is different from the second preset frequency band. Generally, band n261 has a resonance frequency point of 28 GHz, and band n260 has a resonance frequency band of 39 GHz. 
     The resonant structure  230  is carried on the substrate  210 . The resonant structure  230  can be disposed corresponding to the entire substrate  210 , and can also be disposed corresponding to part of the substrate  210 . As illustrated in the schematic view of this implementation, for example, the resonant structure  230  is carried on the substrate  210  and disposed corresponding to the entire substrate  210 . The first preset direction range can be exactly the same as the second preset direction range. The first preset direction range can also be different from the second preset direction range, as long as the first preset direction range and the second preset direction range have an overlapped region and the resonant structure is at least partially located in the overlapped region. 
     The resonant structure  230  has in-phase reflection characteristics to the first RF signal, which means that when the first RF signal is incident on the resonant structure  230 , a reflection phase of the first RF signal is the same as an incident phase of the first RF signal, or means that the reflection phase of the first RF signal is not equal to the incident phase of the first RF signal but a difference between the reflection phase of the first RF signal and the incident phase of the first RF signal is within a first preset phase range, so that the first RF signal can penetrate the antenna radome  200 . Generally, the first preset phase range is −90° ˜0 and 0˜+90°. In other words, when the first RF signal is incident on the resonant structure  230 , and the difference between the reflection phase of the first RF signal and the incident phase of the first RF signal is in a range of −90° ˜+90°, the resonant structure  230  has the in-phase reflection characteristics to the first RF signal. 
     Correspondingly, the resonant structure  230  has in-phase reflection characteristics to the second RF signal, which means that when the second RF signal is incident on the resonant structure  230 , a reflection phase of the second RF signal is the same as an incident phase of the second RF signal, or means that the reflection phase of the second RF signal is not equal to the incident phase of the second RF signal but a difference between the reflection phase of the second RF signal and the incident phase of the second RF signal is within a second preset phase range, so that the second RF signal can penetrate the antenna radome  200 . It should be noted that the first preset phase range may be the same as or different from the second preset phase range. Generally, the second preset phase range is −90° ˜0 and 0˜+90°. In other words, when the second RF signal is incident on the resonant structure  230 , and the difference between the reflection phase of the second RF signal and the incident phase of the second RF signal is in a range of −90° ˜+90°, the resonant structure  230  has the in-phase reflection characteristics to the second RF signal. 
     The resonant structure  230  in the antenna apparatus  10  of this implementation has the in-phase reflection characteristics to the first RF signal in the first preset frequency band, and the first RF signal in the first preset frequency band can pass through the resonant structure  230 . Correspondingly, the resonant structure  230  also has the in-phase reflection characteristics to the second RF signal in the second preset frequency band, and the second RF signal in the second preset frequency band can pass through the resonant structure  230 . In this way, the antenna apparatus  10  can operate in two frequency bands. Further, the first RF signal and the second RF signal have good directivity and high gain after passing through the antenna radome  200  (see a simulation diagram in  FIG. 39  and related description). That is, the resonant structure  230  can compensate for losses of the first RF signal and the second RF signal during transmission, so that the first RF signal and the second RF signal can communicate over longer distances. Therefore, the antenna apparatus  10  of the present disclosure is beneficial to improving communication performance of the electronic device to which the antenna apparatus  10  is applied. 
     Further, the substrate  210  has a first surface  211  and a second surface  212  opposite to the first surface  211 . The first surface  211  is farther away from the antenna module  100  than the second surface  212 . In this implementation, the resonant structure  230  is disposed on the first surface  211 . 
     Reference is made to  FIG. 2 , which is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. An antenna apparatus  10  includes an antenna module  100  and an antenna radome  200 . The antenna module  100  is configured to receive/emit a first RF signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range. The first preset frequency band is lower than the second preset frequency band. The first preset direction range and the second preset direction range have an overlapped region. The antenna radome  200  is spaced apart from the antenna module  100  and includes a substrate  210  and a resonant structure  230  carried on the substrate  210 . The resonant structure  230  is at least partially located in the overlapped region. The resonant structure  230  has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     Further, the substrate  210  has a first surface  211  and a second surface  212  opposite to the first surface  211 . The first surface  211  is farther away from the antenna module  100  than the second surface  212 . In this implementation, the resonant structure  230  is disposed on the second surface  212 . 
     Reference is made to  FIG. 3 , which is a cross-sectional structural view of an antenna apparatus provided in an implementation of the present disclosure. An antenna apparatus  10  includes an antenna module  100  and an antenna radome  200 . The antenna module  100  is configured to receive/emit a first RF signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range. The first preset frequency band is lower than the second preset frequency band. The first preset direction range and the second preset direction range have an overlapped region. The antenna radome  200  is spaced apart from the antenna module  100  and includes a substrate  210  and a resonant structure  230  carried on the substrate  210 . The resonant structure  230  is at least partially located in the overlapped region. The resonant structure  230  has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     Further, the substrate  210  has a first surface  211  and a second surface  212  opposite to the first surface  211 . The first surface  211  is farther away from the antenna module  100  than the second surface  212 . In this implementation, the resonant structure  230  is embedded in the substrate  210  and between the first surface  211  and the second surface  212 . 
     Reference is made to  FIG. 4 , which is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. An antenna apparatus  10  includes an antenna module  100  and an antenna radome  200 . The antenna module  100  is configured to receive/emit a first RF signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range. The first preset frequency band is lower than the second preset frequency band. The first preset direction range and the second preset direction range have an overlapped region. The antenna radome  200  is spaced apart from the antenna module  100  and includes a substrate  210  and a resonant structure  230  carried on the substrate  210 . The resonant structure  230  is at least partially located in the overlapped region. The resonant structure  230  has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     Further, the resonant structure  230  is attached to a carrier film  220 , and the carrier film  220  is adhered to the substrate  210 . In a case that the resonant structure  230  is attached to the carrier film  220 , the carrier film  220  may be, but not limited to, a polyethylene terephthalate (PET) film, a flexible circuit board, a printed circuit board, and the like. The PET film can be, but not limited to, a color film, an explosion-proof film, and the like. The substrate  210  has a first surface  211  and a second surface  212  opposite to the first surface  211 . The first surface  211  is farther away from the antenna module  100  than the second surface  212 . As illustrated in the schematic view of this implementation, for example, the resonant structure  230  is adhered to the second surface  212  via the carrier film  220 . It should be noted that in other implementations, the resonant structure  230  can also be adhered to the first surface  211  via the carrier film  220 . 
     Reference is made to  FIG. 5 , which is a cross-sectional view of an antenna apparatus provided in an implementation of the present disclosure. An antenna apparatus  10  includes an antenna module  100  and an antenna radome  200 . The antenna module  100  is configured to receive/emit a first RF signal in a first preset frequency band in a first preset direction range and receive/emit a second RF signal in a second preset frequency band in a second preset direction range. The first preset frequency band is lower than the second preset frequency band. The first preset direction range and the second preset direction range have an overlapped region. The antenna radome  200  is spaced apart from the antenna module  100  and includes a substrate  210  and a resonant structure  230  carried on the substrate  210 . The resonant structure  230  is at least partially located in the overlapped region. The resonant structure  230  has in-phase reflection characteristics to the first RF signal and in-phase reflection characteristics to the second RF signal. 
     Further, the substrate  210  has a first surface  211  and a second surface  212  opposite to the first surface  211 . The first surface  211  is farther away from the antenna module  100  than the second surface  212 . Part of the resonant structure  230  is exposed to the outside of the first surface  211 , and the rest of the resonant structure  230  is embedded in the substrate  210 . 
     It should be noted that, in other implementations, part of the resonant structure  230  is disposed on the first surface  211  of the substrate  210  and part of the resonant structure  230  is disposed on the second surface  212  of the substrate  210 . Part of the resonant structure  230  is disposed on the first surface  211  of the substrate  210  as follows: part of the resonant structure  230  is directly disposed on the first surface  211  of the substrate  210 , or part of the resonant structure  230  is adhered to the second surface  211  via the carrier film  220 . Correspondingly, part of the resonant structure  230  is disposed on the second surface  212  of the substrate  210  as follows: part of the resonant structure  230  is disposed on the second surface  212  of the substrate  210 , or part of the resonant structure  230  is adhered to the second surface via the carrier film  220 . 
     In combination with the antenna apparatus  10  provided in any of the foregoing implementations, the resonant structure  230  is made of a metal material or a non-metal conductive material. In a case that the resonant structure  230  is made of a non-metal conductive material, the resonant structure  230  may be transparent or non-transparent. The resonant structure  230  may be integrated or non-integrated. 
     In combination with the antenna apparatus  10  provided in any of the foregoing implementations, the substrate  210  is made of at least one of or a combination of plastics, glass, sapphire, and ceramics. 
     Reference is made to  FIG. 6 , which is a cross-sectional view of the resonant structure provided in an implementation of the present disclosure. The resonant structure  230  can be incorporated into the antenna apparatus  10  provided in any of the foregoing implementations. The resonant structure  230  includes one or more resonant layers  230   a . In a case that the resonant structure  230  includes multiple resonant layers  230   a , the multiple resonant layers  230   a  are stacked in a preset direction and spaced apart from one another. In a case that the resonant structure  230  includes multiple resonant layers  230   a , a dielectric layer  210   a  is sandwiched between two adjacent resonant layers  230   a , and the outermost resonant layer  230   a  may or may not be covered with a dielectric layer  210   a . All dielectric layers  210   a  constitute the substrate  210 . In the schematic view of this implementation, for example, the resonant structure  230  includes three resonant layers  230   a  and two dielectric layers  210   a . Optionally, the preset direction is parallel to a main lobe direction of the first RF signal or a main lobe direction of the second RF signal. In a case that the preset direction is parallel to the main lobe direction of the first RF signal, the first RF signal has good radiation performance. The preset direction refers to a direction of a beam with the maximum radiation intensity in the first RF signal. 
     Reference is made to  FIG. 7 , which is a schematic view illustrating an arrangement of resonant structures provided in an implementation of the present disclosure. A resonant structure  230  may be incorporated into the antenna apparatus  10  provided in any of the foregoing implementations. The resonant structure  230  includes multiple resonant units  230   b  arranged at regular intervals. Regular-interval arrangement of the multiple resonant units  230   b  makes the resonant structure  230  easier to be manufactured. 
     Reference is made to  FIG. 8 , which is a schematic view illustrating an arrangement of resonant structures provided in an implementation of the present disclosure. A resonant structure  230  may be incorporated into the antenna apparatus  10  provided in any of the foregoing implementations. The resonant structure  230  includes multiple resonant units  230   b  arranged at irregular intervals. 
     Optionally, in combination with the antenna apparatus  10  provided in any of the foregoing implementations, the resonant structure  230  at least satisfies: 
     
       
         
           
             
               
                 
                   ( 
                   
                     
                       
                         ϕ 
                         
                           R 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           1 
                         
                       
                       π 
                     
                     - 
                     1 
                   
                   ) 
                 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   4 
                 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   2 
                 
               
             
             = 
             
               
                 
                   ( 
                   
                     
                       
                         ϕ 
                         
                           R 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           2 
                         
                       
                       π 
                     
                     - 
                     1 
                   
                   ) 
                 
                 ⁢ 
                 
                   
                     λ 
                     2 
                   
                   4 
                 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     2 
                   
                   2 
                 
               
             
           
         
       
     
     where ϕ R1  represents a difference between a reflection phase and an incident phase brought by the resonant structure to the first RF signal, λ 1  represents a wavelength of the first RF signal in air, ϕ R2  represents a difference between a reflection phase and an incident phase brought by the resonant structure to the second RF signal, λ 2  represents a wavelength of the second RF signal in air, and Nis a positive integer. 
     For the first RF signal, a conventional ground system is a perfect electrical conductor (PEC), when the first RF signal is incident on the PEC, a phase difference of −π will be generated. Therefore, for the first RF signal, a condition for the antenna radome  200  to realize resonance is: 
     
       
         
           
             h 
             = 
             
               
                 
                   ( 
                   
                     
                       
                         ϕ 
                         
                           R 
                           ⁢ 
                           
                               
                           
                           ⁢ 
                           1 
                         
                       
                       π 
                     
                     - 
                     1 
                   
                   ) 
                 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   4 
                 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   2 
                 
               
             
           
         
       
     
     where h 1  represents a length of a line segment of a center line of a radiation surface of the antenna module  100  from a radiation surface of the antenna module  100  to a surface of the resonant structure  230  facing the antenna module  100 , the center line is a straight line perpendicular to the radiation surface of the antenna module  100 , ϕ R1  represents a difference between a reflection phase and an incident phase brought by the resonant structure  230  to the first RF signal, λ 1  represents a wavelength of the first RF signal in air, and N is a positive integer. When ϕ R1 =0, the resonant structure  230  has in-phase reflection characteristics to the first RF signal, and λ 1  has the minimum value, that is, 
     
       
         
           
             
               
                 h 
                 1 
               
               = 
               
                 
                   λ 
                   1 
                 
                 4 
               
             
             , 
           
         
       
     
     so that the value of λ 1  is significantly reduced. As such, for the first RF signal, a distance from the radiation surface of the antenna module  100  to the surface of the resonant structure  230  facing the antenna module  100  is the minimum distance. Therefore, the antenna apparatus  10  can have a small thickness. In a case that the antenna apparatus  10  is applied to the electronic device, the electronic device can have a small thickness. In this implementation, selection of h 1  can improve directivity and a gain of a beam of the first RF signal, in other words, the resonant structure  230  can compensate for a loss of the first RF signal during transmission, such that the first RF signal can communicate over longer distances. Therefore, the antenna apparatus  10  of the present disclosure is beneficial to improving communication performance of the electronic device to which the antenna apparatus  10  is applied. In addition, compared with designing complex circuits to achieve the same technical effects in tradition technology, the resonant structure  230  in the antenna apparatus  10  of the present disclosure has a simple structure, which is beneficial to improving product competitiveness. 
     In this case, in addition resonance realized by the antenna radome  200 , the maximum value of a directivity coefficient of the first RF signal radiated out through the antenna radome  200  satisfies 
     
       
         
           
             
               
                 D 
                 
                   1 
                   ⁢ 
                   max 
                 
               
               = 
               
                 
                   1 
                   + 
                   
                     R 
                     1 
                   
                 
                 
                   1 
                   - 
                   
                     R 
                     1 
                   
                 
               
             
             , 
           
         
       
     
     where D 1max  represents the directivity coefficient of the first RF signal, R 1 =S 11   2 , and S 11  represents a reflection coefficient of the first RF signal. 
     Correspondingly, for the second RF signal, when the second RF signal is incident on the PEC, a phase difference of −π will be generated. Therefore, for the second RF signal, a condition for the antenna radome  200  to realize resonance is: 
     
       
         
           
             
               h 
               2 
             
             = 
             
               
                 ( 
                 
                   
                     
                       ϕ 
                       
                         R 
                         ⁢ 
                         
                             
                         
                         ⁢ 
                         2 
                       
                     
                     π 
                   
                   - 
                   1 
                 
                 ) 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     2 
                   
                   2 
                 
               
             
           
         
       
     
     where h 2  represents a length of a line segment of a center line of a radiation surface of the antenna module  100  from a radiation surface of the antenna module  100  to a surface of the resonant structure  230  facing the antenna module  100 , the center line is a straight line perpendicular to the radiation surface of the antenna module  100 , ϕ R2  represents a difference between a reflection phase and an incident phase brought by the resonant structure  230  to the second RF signal, λ 2  represents a wavelength of the second RF signal in air, and Nis a positive integer. When ϕ R1 =0, the resonant structure  230  has in-phase reflection characteristics to the second RF signal 
     
       
         
           
             
               
                 h 
                 2 
               
               = 
               
                 
                   λ 
                   2 
                 
                 4 
               
             
             , 
           
         
       
     
     so that the value of λ 2  is significantly reduced. As such, for the second RF signal, a distance from the radiation surface of the antenna module  100  to the surface of the resonant structure  230  facing the antenna module  100  is the minimum distance. Therefore, the antenna apparatus  10  can have a small thickness. In a case that the antenna apparatus  10  is applied to the electronic device, the electronic device can have a small thickness. In this implementation, selection of h 2  can improve directivity and a gain of a beam of the second RF signal, in other words, the resonant structure  230  can compensate for a loss of the second RF signal during transmission, such that the second RF signal can communicate over longer distances. Therefore, the antenna apparatus  10  of the present disclosure is beneficial to improving the communication performance of the electronic device to which the antenna apparatus  10  is applied. In addition, compared with designing complex circuits to achieve the same technical effects in tradition technology, the resonant structure  230  in the antenna apparatus  10  of the present disclosure has a simple structure, which is beneficial to improving product competitiveness. 
     In this case, in addition resonance realized by the antenna radome  200 , the maximum value of a directivity coefficient of the second RF signal radiated out through the antenna radome  200  satisfies: 
     
       
         
           
             
               
                 D 
                 
                   2 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   max 
                 
               
               = 
               
                 
                   1 
                   + 
                   
                     R 
                     2 
                   
                 
                 
                   1 
                   - 
                   
                     R 
                     2 
                   
                 
               
             
             , 
           
         
       
     
     where D 2 max  represents the directivity coefficient of the second RF signal, R 2 =S′ 11   2 , and S′ 11  represents a reflection coefficient of the second RF signal. 
     In the antenna apparatus  10 , h 1 =h 2 , therefore, the following is satisfied: 
     
       
         
           
             
               
                 
                   ( 
                   
                     
                       
                         ϕ 
                         
                           R 
                           ⁢ 
                           1 
                         
                       
                       π 
                     
                     - 
                     1 
                   
                   ) 
                 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   4 
                 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     1 
                   
                   2 
                 
               
             
             = 
             
               
                 
                   ( 
                   
                     
                       
                         ϕ 
                         
                           R 
                           ⁢ 
                           2 
                         
                       
                       π 
                     
                     - 
                     1 
                   
                   ) 
                 
                 ⁢ 
                 
                   
                     λ 
                     2 
                   
                   4 
                 
               
               + 
               
                 N 
                 ⁢ 
                 
                   
                     λ 
                     2 
                   
                   2 
                 
               
             
           
         
       
     
     In this case, the resonant structure  230  has the in-phase reflection characteristics to the first RF signal and has the in-phase reflection characteristics to the second RF signal, thereby realizing dual-frequency in-phase reflection. Both the first RF signal and the second RF signal have large gains after passing through the antenna radome  200 , and a distance between the antenna radome  200  and the antenna module  100  can be kept relatively small. When the antenna module  100  is applied to the electronic device  1  (referring to  FIGS. 40 to 42 ), the thickness of the electronic device  1  to which the antenna module  100  is applied can be reduced. 
     Reference is made to  FIG. 9 , which is a cross-sectional view of a resonant structure provided in an implementation of the present disclosure. A resonant structure  230  may be incorporated into the antenna apparatus  10  provided in any of the foregoing implementations. The resonant structure  230  includes a first sub-resonant structure  231  and a second sub-resonant structure  232  spaced apart from the first sub-resonant structure  231 . The first sub-resonant structure  231  has in-phase reflection characteristics to the first RF signal, and the second sub-resonant structure  232  has in-phase reflection characteristics to the second RF signal. 
     Specifically, the first sub-resonant structure  231  has the in-phase reflection characteristics to the first RF signal, which means that when the first RF signal is incident on the first sub-resonant structure  231 , a reflection phase of the first RF signal is the same as an incident phase of the first RF signal, or means that the reflection phase of the first RF signal is not equal to the incident phase of the first RF signal but a difference between the reflection phase of the first RF signal and the incident phase of the first RF signal is within a first preset phase range, so that the first RF signal can penetrate the antenna radome  200 . The first preset phase range can refer to the foregoing description, which will not be repeated herein. 
     Correspondingly, the second sub-resonant structure  232  has the in-phase reflection characteristics to the second RF signal, which means that when the second RF signal is incident on the second sub-resonant structure  232 , a reflection phase of the second RF signal is the same as an incident phase of the second RF signal, or means that the reflection phase of the second RF signal is not equal to the incident phase of the second RF signal but a difference between the reflection phase of the second RF signal and the incident phase of the second RF signal is within a second preset phase range, so that the second RF signal can penetrate the antenna radome  200 . The second preset phase range can refer to the foregoing description, which will not be repeated herein. 
     It should be noted that, the first sub-resonant structure  231  and the second sub-resonant structure  232  can be arranged at completely different layers. Alternatively, part of the first sub-resonant structure  231  and part of the second sub-resonant structure  232  are arranged at different layers, and the rest of the first sub-resonant structure  231  and the rest of the second sub-resonant structure  232  are arranged at the same layer. 
     The first sub-resonant structure  231  in the antenna apparatus  10  of this implementation has the in-phase reflection characteristics to the first RF signal in the first preset frequency band, and the first RF signal in the first preset frequency band can pass through the first sub-resonant structure  231 . Correspondingly, the second sub-resonant structure  232  also has the in-phase reflection characteristics to the second RF signal in the second preset frequency band, and the second RF signal in the second preset frequency band can pass through the second sub-resonant structure  232 . In this way, the antenna apparatus  10  can operate in two frequency bands, which is beneficial to improving the operation performance of the antenna apparatus  10 . 
     Reference is made to  FIGS. 10-12 ,  FIG. 10  is a top view of a resonant structure provided in an implementation of the present disclosure,  FIG. 11  is a bottom view of the resonant structure illustrated in  FIG. 10 , and  FIG. 12  is a cross-sectional view taken along line I-I in  FIG. 10 . In this implementation, the resonant structure  230  includes a first resonant layer  235  and a second resonant layer  236  stacked with the first resonant layer  235 . It should be noted that, for ease of illustration of a correspondence between the first resonant layer  235  in  FIG. 10  and the second resonant layer  236  in  FIG. 11 , the second resonant layer  236  in  FIG. 11  is perspectively illustrated from the same top view angle as that of  FIG. 10 , and in  FIG. 11 , only the second resonant layer  236  and the substrate  210  are illustrated while the first resonant layer  235  is not illustrated. The first resonant layer  235  is farther away from the antenna module  100  than the second resonant layer  236 . The first resonant layer  235  includes first resonant units  2351  arranged at regular intervals (one first resonant unit  2351  is illustrated in figures). The first resonant unit  2351  includes a first resonant patch  2311 . The second resonant layer  236  includes second resonant units  2356  arranged at regular intervals (one second resonant unit  2356  is illustrated in figures). The second resonant unit  2356  includes a second resonant patch  2312 . The first resonant patch  2311  is opposite to the second resonant patch  2312 . The first resonant patch  2311  and the second resonant patch  2312  are conductive patches, and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≤ 
             
               W 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W low_f  represents a side length of the first resonant patch  2311 , L low_f  represents a side length of the second resonant patch  2312 , and the first sub-resonant structure  231  at least includes the first resonant patch  2311  and the second resonant patch  2312 . 
     In this implementation, the first resonant patch  2311  is opposite to the second resonant patch  2312 , which means that the first resonant patch  2311  and the second resonant patch  2312  are opposite to and at least partially overlap with each other. In other words, an orthographic projection of the second resonant patch  2312  on a plane where the first resonant patch  2311  is located at least partially overlaps with a region where the first resonant patch  2311  is located. Optionally, the orthographic projection of the second resonant patch  2312  on the plane where the first resonant patch  2311  is located falls into the region where the first resonant patch  2311  is located. 
     In this implementation, each of the first resonant patch  2311  and the second resonant patch  2312  is a conductive patch and does not define a hollow structure therein. Each of the first resonant patch  2311  and the second resonant patch  2312  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the first resonant patch  2311  and the second resonant patch  2312  is square. A structural form of the first sub-resonant structure  231  in this implementation can improve a gain of the first RF signal in the first preset frequency band. 
     Optionally, the first resonant unit  2351  includes a third resonant patch  2321  spaced apart from the first resonant patch  2311 , a side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The second resonant unit  2356  includes a fourth resonant patch  2322  spaced apart from the second resonant patch  2312 . A side length of the fourth resonant patch  2322  is less than the side length of the second resonant patch  2312 . The fourth resonant patch  2322  is opposite to the third resonant patch  2321 , the third resonant patch  2321  and the fourth resonant patch  2322  are conductive patches, and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   high 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≤ 
             
               W 
               
                 
                   high 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W high_f  represents the side length of the third resonant patch  2321 , L high_f  represents the side length of the fourth resonant patch  2322 , and the second sub-resonant structure  232  at least includes the third resonant patch  2321  and the fourth resonant patch  2322 . A structural form of the second sub-resonant structure  232  in this implementation can improve a gain of the second RF signal in the second preset frequency band. 
     In this implementation, the fourth resonant patch  2322  is opposite to the third resonant patch  2321 , which means that the fourth resonant patch  2322  and the third resonant patch  2321  are opposite to and at least partially overlap with each other. In other words, an orthographic projection of the fourth resonant patch  2322  on a plane where the third resonant patch  2321  is located at least partially overlaps with a region where the third resonant patch  2321  is located. Optionally, the orthographic projection of the fourth resonant patch  2322  on the plane where the third resonant patch  2321  is located falls into the region where the third resonant patch  2321  is located. 
     In this implementation, each of the third resonant patch  2321  and the fourth resonant patch  2322  is a conductive patch and does not define a hollow structure therein. Each of the third resonant patch  2321  and the fourth resonant patch  2322  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the third resonant patch  2321  and the fourth resonant patch  2322  is square. A structural form of the second sub-resonant structure  232  in this implementation can improve a gain of the second RF signal in the second preset frequency band. 
     Optionally, the first resonant unit  2351  further includes another first resonant patch  2311  and another third resonant patch  2321 . The two first resonant patches  2311  are diagonally arranged and spaced apart from each other. The side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The two third resonant patches  2321  are arranged diagonally and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. 
     Optionally, a center of the two first resonant patches  2311  coincides with a center of the two third resonant patches  2321 . The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. 
     Optionally, the second resonant unit  2356  further includes another second resonant patch  2312  and another fourth resonant patch  2322 . The two second resonant patches  2312  are diagonally arranged and spaced apart from each other. The two fourth resonant patches  2322  are diagonally arranged and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. 
     Optionally, a center of the two second resonant patches  2312  coincides with a center of the two fourth resonant patches  2322 . The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. 
     Reference is made to  FIGS. 13-15 ,  FIG. 13  is a top view of a resonant structure provided in an implementation of the present disclosure,  FIG. 14  is a bottom view of the resonant structure illustrated in  FIG. 13 , and  FIG. 15  is a cross-sectional view taken along line II-II in  FIG. 13 . In this implementation, the resonant structure  230  includes a first resonant layer  235  and a second resonant layer  236  stacked with the first resonant layer  235 . It should be noted that, for ease of illustration of a correspondence between the first resonant layer  235  in  FIG. 13  and the second resonant layer  236  in  FIG. 14 , the second resonant layer  236  in  FIG. 14  is perspectively illustrated from the same top view angle as that of  FIG. 13 , and in  FIG. 14 , only the second resonant layer  236  and the substrate  210  are illustrated while the first resonant layer  235  is not illustrated. The first resonant layer  235  is farther away from the antenna module  100  than the second resonant layer  236 . The first resonant layer  235  includes first resonant units  2351  arranged at regular intervals. The first resonant unit  2351  includes a first resonant patch  2311 . The second resonant layer  236  includes second resonant units  2356  arranged at regular intervals. The second resonant unit  2356  includes a second resonant patch  2312 . The first resonant patch  2311  is opposite to the second resonant patch  2312 . The first resonant patch  2311  a conductive patch, the second resonant patch  2312  is a conductive patch and defines a first hollow structure  231   a  penetrating two opposite surfaces of the second resonant patch  2312 , and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≤ 
             
               W 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W low_f  represents a side length of the first resonant patch  2311 , L low_f  represents a side length of the second resonant patch  2312 , a difference between L low_f  and W low_f  increases as an area of the first hollow structure  231   a  increases, and the first sub-resonant structure  231  at least includes the first resonant patch  2311  and the second resonant patch  2312 . 
     In this implementation, the first resonant patch  2311  is opposite to the second resonant patch  2312 , which means that the first resonant patch  2311  and the second resonant patch  2312  are opposite to and at least partially overlap with each other. In other words, an orthographic projection of the second resonant patch  2312  on a plane where the first resonant patch  2311  is located at least partially overlaps with a region where the first resonant patch  2311  is located. In this implementation, each of the first resonant patch  2311  and the second resonant patch  2312  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the first resonant patch  2311  and the second resonant patch  2312  is square, and the first hollow structure  231   a  is square. In other implementations, the first hollow structure  231   a  may also be in a shape of circle, ellipse, triangle, rectangle, hexagon, ring, cross, Jerusalem cross, or the like. A structural form of the first sub-resonant structure  231  in this implementation can improve a gain of the first RF signal in the first preset frequency band. Furthermore, compared with the second resonant patch  2312  without the first hollow structure  231   a , a surface current distribution on the second resonant patch  2312  can be changed with the aid of the first hollow structure  231   a  which is defined in the second resonant patch  2312  and penetrates the two opposite surfaces of the second resonant patch  2312 , which in turn increases an electrical length of the second resonant patch  2312 . That is, for the first RF signal in the first preset frequency band, a size of the second resonant patch  2312  with the first hollow structure  231   a  is less than a side length of the second resonant patch  2312  without the first hollow structure  231   a . Moreover, for the first RF signal in the first preset frequency band, the greater a hollow area of the first hollow structure  231   a , the less the side length of the second resonant patch  2312 , which is beneficial to improving an integration of the antenna radome  200 . 
     Optionally, the first resonant unit  2351  includes a third resonant patch  2321  spaced apart from the first resonant patch  2311 . The side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The second resonant unit  2356  includes a fourth resonant patch  2322  spaced apart from the second resonant patch  2356 . A side length of the fourth resonant patch  2322  is less than the side length of the second resonant patch  2312 . The fourth resonant patch  2322  is opposite to the third resonant patch  2321 . An orthographic projection of the fourth resonant patch  2322  on a plane where the third resonant patch  2321  is located at least partially overlaps with a region where the third resonant patch  2321  is located. The third resonant patch  2321  and the fourth resonant patch  2322  are conductive patches, and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   high 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≤ 
             
               W 
               
                 
                   high 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W high_f  represents a side length of the third resonant patch  2321 , L high_f  represents the side length of the fourth resonant patch  2322 , and the second sub-resonant structure  232  at least includes the third resonant patch  2321  and the fourth resonant patch  2322 . A structural form of the second sub-resonant structure  232  in this implementation can improve the gain of the second RF signal in the second preset frequency band. 
     Optionally, the first resonant unit  2351  further includes another first resonant patch  2311  and another third resonant patch  2321 . The two first resonant patches  2311  are diagonally arranged and spaced apart from each other. The side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The two third resonant patches  2321  are arranged diagonally and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. 
     Optionally, a center of the two first resonant patches  2311  as a whole coincides with a center of the two third resonant patches  2321  as a whole. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. It should be noted that the center of the two first resonant patches  2311  as a whole refers to the center of a “whole” with the two first resonant patches  2311  as a whole, rather than a center of each of the two first resonant patches  2311 . For ease of description, the center of the “whole” of the two first resonant patches  2311  is denoted as a first center. The center of the two third resonant patches  2321  as a whole refers to the center of a “whole” with the two third resonant patches  2321  as a whole, rather than a center of each of the two third resonant patches  2321 . For ease of description, the center of the “whole” of the two third resonant patches  2321  is denoted as the second center. The second center coincides with the first center. 
     Optionally, the second resonant unit  2356  further includes another second resonant patch  2312  and another fourth resonant patch  2322 . The two second resonant patches  2312  are diagonally arranged and spaced apart from each other. The two fourth resonant patches  2322  are diagonally arranged and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. 
     Optionally, a center of the two second resonant patches  2312  as a whole coincides with a center of the two fourth resonant patches  2322  as a whole. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. It should be noted that the center of the two second resonant patches  2312  as a whole refers to the center of a “whole” with the two second resonant patches  2312  as a whole, rather than a center of each of the two second resonant patches  2312 . For ease of description, the center of the “whole” of the two second resonant patches  2312  is denoted as a third center. The center of the two fourth resonant patches  2322  as a whole refers to the center of a “whole” with the two fourth resonant patches  2322  as a whole, rather than a center of each of the two fourth resonant patches  2322 . For ease of description, the center of the “whole” of the two fourth resonant patches  2322  is denoted as the fourth center. The third center coincides with the fourth center. 
     Reference is made to  FIGS. 16-18 ,  FIG. 16  is a top view of a resonant structure provided in an implementation of the present disclosure,  FIG. 17  is a bottom view of the resonant structure illustrated in  FIG. 16 , and  FIG. 18  is a cross-sectional view taken along line III-III in  FIG. 16 . In this implementation, the resonant structure  230  includes a first resonant layer  235  and a second resonant layer  236  stacked with the first resonant layer  235 . It should be noted that, for ease of illustration of a correspondence between the first resonant layer  235  in  FIG. 16  and the second resonant layer  236  in  FIG. 17 , the second resonant layer  236  in  FIG. 17  is perspectively illustrated from the same top view angle as that of  FIG. 16 , and in  FIG. 17 , only the second resonant layer  236  and the substrate  210  are illustrated while the first resonant layer  235  is not illustrated. The first resonant layer  235  is farther away from the antenna module  100  than the second resonant layer  236 . The first resonant layer  235  includes first resonant units  2351  arranged at regular intervals. The first resonant unit  2351  includes a first resonant patch  2311 . The second resonant layer  236  includes second resonant units  2356  arranged at regular intervals. The second resonant unit  2356  includes a second resonant patch  2312 . The first resonant patch  2311  is opposite to the second resonant patch  2312 , and an orthographic projection of the second resonant patch  2312  on a plane where the first resonant patch  2311  is located at least partially overlaps with a region where the first resonant patch  2311  is located. The first resonant patch  2311  and the second resonant patch  2312  are conductive patches, and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≤ 
             
               W 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W low_f  represents a side length of the first resonant patch  2311 , L low_f  represents a side length of the second resonant patch  2312 , and the first sub-resonant structure  231  at least includes the first resonant patch  2311  and the second resonant patch  2312 . 
     In this implementation, each of the first resonant patch  2311  and the second resonant patch  2312  is a conductive patch and does not define a hollow structure therein. Each of the first resonant patch  2311  and the second resonant patch  2312  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the first resonant patch  2311  and the second resonant patch  2312  is square. A structural form of the first sub-resonant structure  231  in this implementation can improve a gain of the first RF signal in the first preset frequency band. 
     Optionally, the first resonant unit  2351  includes a third resonant patch  2321  spaced apart from the first resonant patch  2311 , a side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The second resonant unit  2356  includes a fourth resonant patch  2322  spaced apart from the second resonant patch  2312 . A side length of the fourth resonant patch  2322  is less than the side length of the second resonant patch  2312 . The fourth resonant patch  2322  is opposite to the third resonant patch  2321 , and an orthographic projection of the fourth resonant patch  2322  on a plane where the third resonant patch  2321  is located at least partially overlaps with a region where the third resonant patch  2321  is located. The third resonant patch  2321  is a conductive patch, the fourth resonant patch  2322  is a conductive patch and defines a second hollow structure  232   a  penetrating two opposite surfaces of the fourth resonant patch  2322 , and the following is satisfied: 
     
       
         
           
             
               L 
               high_f 
             
             ≥ 
             
               W 
               high_f 
             
           
         
       
     
     where W high_f  represents the side length of the third resonant patch  2321 , L high_f  represents the side length of the fourth resonant patch  2322 , a difference between L high_f  and W high_f  increases as an area of the second hollow structure  232   a  increases, and the second sub-resonant structure  232  at least includes the third resonant patch  2321  and the fourth resonant patch  2322 . 
     In this implementation, each of the third resonant patch  2321  and the fourth resonant patch  2322  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the third resonant patch  2321  and the fourth resonant patch  2322  is square, and the second hollow structure  232   a  is square. In other implementations, the second hollow structure  232   a  may also be in a shape of circle, ellipse, triangle, rectangle, hexagon, ring, cross, Jerusalem cross, or the like. A structural form of the second sub-resonant structure  232  in this implementation can improve a gain of the second RF signal in the second preset frequency band. Furthermore, a surface current distribution on the fourth resonant patch  2322  can be changed with the aid of the second hollow structure  232   a  which is defined in the fourth resonant patch  2322  and penetrates the two opposite surfaces of the fourth resonant patch  2322 , which in turn increases an electrical length of the fourth resonant patch  2322 . That is, for the second RF signal in the second preset frequency band, a size of the fourth resonant patch  2322  with the second hollow structure  232   a  is less than a side length of the fourth resonant patch  2322  without the second hollow structure  232   a . Moreover, for the second RF signal in the second preset frequency band, the greater a hollow area of the second hollow structure  232   a , the less the side length of the fourth resonant patch  2322 , which is beneficial to improving an integration of the antenna radome  200 . 
     Optionally, the first resonant unit  2351  further includes another first resonant patch  2311  and another third resonant patch  2321 . The two first resonant patches  2311  are diagonally arranged and spaced apart from each other. The side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The two third resonant patches  2321  are arranged diagonally and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. 
     Optionally, a center of the two first resonant patches  2311  as a whole coincides with a center of the two third resonant patches  2321  as a whole. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. For a specific explanation that the center of the two first resonant patches  2311  as a whole coincides with the center of the two third resonant patches  2321  as a whole, reference can be made to the foregoing related description, which will not be repeated herein. 
     Optionally, the second resonant unit  2356  further includes another second resonant patch  2312  and another fourth resonant patch  2322 . The two second resonant patches  2312  are diagonally arranged and spaced apart from each other. The two fourth resonant patches  2322  are diagonally arranged and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. 
     Optionally, a center of the two second resonant patches  2312  as a whole coincides with a center of the two fourth resonant patches  2322  as a whole. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. For a specific explanation that the center of the two second resonant patches  2312  as a whole coincides with a center of the two fourth resonant patches  2322  as a whole, reference can be made to the foregoing related description, which will not be repeated herein. 
     Reference is made to  FIGS. 19-21 ,  FIG. 19  is a top view of a resonant structure provided in an implementation of the present disclosure,  FIG. 20  is a bottom view of the resonant structure illustrated in  FIG. 19 , and  FIG. 21  is a cross-sectional view taken along line IV-IV in  FIG. 19 . In this implementation, the resonant structure  230  includes a first resonant layer  235  and a second resonant layer  236  stacked with the first resonant layer  235 . It should be noted that, for ease of illustration of a correspondence between the first resonant layer  235  in  FIG. 19  and the second resonant layer  236  in  FIG. 20 , the second resonant layer  236  in  FIG. 20  is perspectively illustrated from the same top view angle as that of  FIG. 19 , and in  FIG. 20 , only the second resonant layer  236  and the substrate  210  are illustrated while the first resonant layer  235  is not illustrated. The first resonant layer  235  is farther away from the antenna module  100  than the second resonant layer  236 . The first resonant layer  235  includes first resonant units  2351  arranged at regular intervals. The first resonant unit  2351  includes a first resonant patch  2311 . The second resonant layer  236  includes second resonant units  2356  arranged at regular intervals. The second resonant unit  2356  includes a second resonant patch  2312 . The first resonant patch  2311  is opposite to the second resonant patch  2312 , and an orthographic projection of the second resonant patch  2312  on a plane where the first resonant patch  2311  is located at least partially overlaps with a region where the first resonant patch  2311  is located. The first resonant patch  2311  is a conductive patch, the second resonant patch  2312  is a conductive patch and defines a first hollow structure  231   a  penetrating two opposite surfaces of the second resonant patch  2312 , and the following is satisfied: 
     
       
         
           
             
               L 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
             ≥ 
             
               W 
               
                 
                   low 
                   - 
                 
                 ⁢ 
                 f 
               
             
           
         
       
     
     where W low_f  represents a side length of the first resonant patch  2311 , L low_f  represents a side length of the second resonant patch  2312 , a difference between L low_f  and W low_f  increases as an area of the first hollow structure  231   a  increases, and the first sub-resonant structure  231  at least includes the first resonant patch  2311  and the second resonant patch  2312 . 
     In this implementation, each of the first resonant patch  2311  and the second resonant patch  2312  can be in a shape of square, polygon, etc. In the schematic view of this implementation, for example, each of the first resonant patch  2311  and the second resonant patch  2312  is square, and the first hollow structure  231   a  is square. The first hollow structure  231   a  can refer to the foregoing implementations, which will not be repeated herein. A structural form of the first sub-resonant structure  231  in this implementation can improve a gain of the first RF signal in the first preset frequency band. Furthermore, compared with the second resonant patch  2312  without the first hollow structure  231   a , a surface current distribution on the second resonant patch  2312  can be changed with the aid of the first hollow structure  231   a  which is defined in the second resonant patch  2312  and penetrates the two opposite surfaces of the second resonant patch  2312 , which in turn increases an electrical length of the second resonant patch  2312 . That is, for the first RF signal in the first preset frequency band, a size of the second resonant patch  2312  with the first hollow structure  231   a  is less than a side length of the second resonant patch  2312  without the first hollow structure  231   a . Moreover, for the first RF signal in the first preset frequency band, the greater a hollow area of the first hollow structure  231   a , the less the side length of the second resonant patch  2312 , which is beneficial to improving an integration of the antenna radome  200 . 
     Optionally, the first resonant unit  2351  includes a third resonant patch  2321  spaced apart from the first resonant patch  2311 , a side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The second resonant unit  2356  includes a fourth resonant patch  2322  spaced apart from the second resonant patch  2312 . A side length of the fourth resonant patch  2322  is less than the side length of the second resonant patch  2312 . The fourth resonant patch  2322  is opposite to the third resonant patch  2321 , and an orthographic projection of the fourth resonant patch  2322  on a plane where the third resonant patch  2321  is located at least partially overlaps with a region where the third resonant patch  2321  is located. The third resonant patch  2321  is a conductive patch, the fourth resonant patch  2322  is a conductive patch and defines a second hollow structure  232   a  penetrating two opposite surfaces of the fourth resonant patch  2322 , and the following is satisfied: 
     
       
         
           
             
               L 
               high_f 
             
             ≥ 
             
               W 
               high_f 
             
           
         
       
     
     where W high_f  represents the side length of the third resonant patch  2321 , L high_f  represents the side length of the fourth resonant patch  2322 , a difference between L high_f  and W high_f  increases as an area of the second hollow structure  232   a  increases, and the second sub-resonant structure  232  at least includes the third resonant patch  2321  and the fourth resonant patch  2322 . The second hollow structure  232   a  can refer to the foregoing implementations, which will not be repeated herein. A structural form of the second sub-resonant structure  232  in this implementation can improve a gain of the second RF signal in the second preset frequency band. Furthermore, a surface current distribution on the fourth resonant patch  2322  can be changed with the aid of the second hollow structure  232   a  which is defined in the fourth resonant patch  2322  and penetrates the two opposite surfaces of the fourth resonant patch  2322 , which in turn increases an electrical length of the fourth resonant patch  2322 . That is, for the second RF signal in the second preset frequency band, a size of the fourth resonant patch  2322  with the second hollow structure  232   a  is less than a side length of the fourth resonant patch  2322  without the second hollow structure  232   a . Moreover, for the second RF signal in the second preset frequency band, the greater a hollow area of the second hollow structure  232   a , the less the side length of the fourth resonant patch  2322 , which is beneficial to improving an integration of the antenna radome  200 . 
     Optionally, the first resonant unit  2351  further includes another first resonant patch  2311  and another third resonant patch  2321 . The two first resonant patches  2311  are diagonally arranged and spaced apart from each other. The side length of the third resonant patch  2321  is less than the side length of the first resonant patch  2311 . The two third resonant patches  2321  are arranged diagonally and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. 
     Optionally, a center of the two first resonant patches  2311  as a whole coincides with a center of the two third resonant patches  2321  as a whole. The resonant structure  230  in this implementation can further improve the gain of the first RF signal in the first preset frequency band. For a specific explanation that the center of the two first resonant patches  2311  as a whole coincides with the center of the two third resonant patches  2321  as a whole, reference can be made to the foregoing related description, which will not be repeated herein. 
     Optionally, the second resonant unit  2356  further includes another second resonant patch  2312  and another fourth resonant patch  2322 . The two second resonant patches  2312  are diagonally arranged and spaced apart from each other. The two second resonant patches  2312  are diagonally arranged and spaced apart from each other. The two fourth resonant patches  2322  are diagonally arranged and spaced apart from each other. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. 
     Optionally, a center of the two second resonant patches  2312  as a whole coincides with a center of the two fourth resonant patches  2322  as a whole. The resonant structure  230  in this implementation can further improve the gain of the second RF signal in the second preset frequency band. For a specific explanation that the center of the two second resonant patches  2312  as a whole coincides with a center of the two fourth resonant patches  2322  as a whole, reference can be made to the foregoing related description, which will not be repeated herein. 
     The first resonant patch  2311  and the second resonant patch  2312  described above are connected without a connecting member. Reference is made to  FIG. 22 , which is a cross-sectional view of a resonant structure provided in an implementation of the present disclosure. The resonant structure  230  provided in this implementation is substantially the same as the resonant structure  230  illustrated in  FIG. 13  except that in this implementation, the center of the first resonant patch  2311  is electrically connected with the center of the second resonant patch  2312  via the connecting member  2313 . In this implementation, the first resonant patch  2311  is electrically connected with the second resonant patch  2312  via the connecting member  2313 , so that a high impedance surface can be formed on the antenna radome  200  and the RF signal cannot propagate along a surface of the antenna radome  200 , which can improve a gain and a bandwidth of the first RF signal, and reduce a back lobe, thereby improving a communication quality when the antenna apparatus  10  communicates through the RF signal. Furthermore, the center of the first resonant patch  2311  is electrically connected with the center of the second resonant patch  2312 , which can further improve the gain and the bandwidth of the first RF signal, and reduce the back lobe, thereby improving the communication quality when the antenna apparatus  10  communicates through the first RF signal. 
     Reference is made to  FIG. 23 , which is a schematic view of a resonant structure provided in an implementation of the present disclosure. The resonant structure  230  includes multiple first conductive lines  151  spaced apart from one another and multiple second conductive lines  161  spaced apart from one another. The multiple first conductive lines  151  are intersected with the multiple second conductive lines  161 , and the multiple first conductive lines  151  are electrically connected with the multiple second conductive lines  161  at intersections. 
     It can be understood that, the first conductive lines  151  are arranged at intervals in a first direction, and the second conductive lines  161  are arranged at intervals in a second direction. The two first conductive lines  151  arranged at intervals in the first direction intersect with the second conductive lines  161  arranged at intervals in the second direction to form a grid structure. It can be understood that, in an implementation, the first direction is perpendicular to the second direction. In other implementations, the first direction is not perpendicular to the second direction. It can be understood that, for the multiple first conductive lines  151  arranged at intervals in the first direction, a distance between each two adjacent first conductive lines  151  may be the same as or different from each other. Correspondingly, for the multiple second conductive lines  161  arranged at intervals in the second direction, a distance between each two adjacent second conductive lines  161  may be the same as or different from each other. In the schematic view of this implementation, for example, the first direction is perpendicular to the second direction, distances between each two adjacent first conductive lines  151  are equal to each other, and distances between each adjacent two second conductive lines  161  are equal to one another. In the resonant structure in this implementation, the first conductive lines  151  and the second conductive lines  161  form a grid structure. Compared with a resonant structure  230  in a form of conductive patches without grids, a surface current distribution on the resonant structure  230  with the grid structure is different from a surface current distribution of the resonant structure  230  without the grid structure, which in turn increases an electrical length of the resonant structure  230 . For an RF signal in a preset frequency band, a size of the resonant structure  230  with the grid structure is less than that of the resonant structure  230  without the grid structure, which is beneficial to improving the integration of the antenna radome  200 . 
     Reference is made to  FIG. 24 , which is a schematic view illustrating a resonant structure provided in an implementation of the present disclosure. The resonant structure  230  includes multiple conductive grids  163  arranged in arrays, each of the multiple conductive grids  163  is enclosed by at least one conductive line  151 , and two adjacent conductive grids  163  at least partially share the at least one conductive line  151 . The conductive grid  163  may have, but not limited to, any shape of circle, rectangle, triangle, polygon, and ellipse. In a case that the conductive grid  163  is in a shape of polygon, the number of sides of the conductive grid  163  is a positive integer greater than three. In the schematic view of this implementation, for example, the conductive grid  163  is in a shape of triangle. The resonant structure  230  in this implementation includes multiple conductive grids  163 . Compared with the resonant structure  230  without the conductive grid  163 , a surface current distribution on the resonant structure  230  with the grid structure is different from a surface current distribution of the resonant structure  230  without the conductive grid  163 , which in turn increases an electrical length of the resonant structure  230 . For the RF signal in the preset frequency band, a size of the resonant structure  230  with the conductive grid  163  is less than that of the resonant structure  230  without the conductive grid  163 , which is beneficial to improving the integration of the antenna radome  200 . 
     Reference is made to  FIG. 25 , which is a schematic view of a resonant structure provided in an implementation of the present disclosure. In the schematic view of this implementation, for example, the conductive grid  163  is in a shape of regular hexagon. 
     Reference is made to  FIGS. 26 to 33 , which are schematic views illustrating resonant units in a resonant structure. The resonant unit illustrated in  FIG. 26  is a circular patch. The resonant unit illustrated in  FIG. 27  is a regular hexagonal patch. The resonant unit  230   b  illustrated in  FIGS. 28-33  has a hollow structure, and the resonant unit  230   b  can be the foregoing second resonant patch  2312  having the first hollow structure  231   a , or the foregoing fourth resonant patch  2322  having the second hollow structure  232   a.    
     In an possible implementation, a distance between a radiation surface of the resonant structure  230  facing the antenna module  100  and a radiation surface of the antenna module  100  satisfies: 
     
       
         
           
             
               h 
               = 
               
                 
                   
                     ( 
                     
                       
                         
                           ϕ 
                           
                             R 
                             ⁢ 
                             1 
                           
                         
                         π 
                       
                       - 
                       1 
                     
                     ) 
                   
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     4 
                   
                 
                 + 
                 
                   N 
                   ⁢ 
                   
                     
                       λ 
                       1 
                     
                     2 
                   
                 
               
             
             , 
           
         
       
     
     where h represents a length of a line segment of a center line of the radiation surface of the antenna module  100  from the radiation surface to a surface of the resonant structure  230  facing the antenna module  100 , the center line is a straight line perpendicular to the radiation surface of the antenna module  100 , ϕ R1  represents a difference between a reflection phase and an incident phase brought by the resonant structure  230  to the first RF signal, λ 1  represents a wavelength of the first RF signal in air, and Nis a positive integer. 
     When ϕ R1 =0, the resonant structure  230  has in-phase reflection characteristics to the first RF signal, and the minimum value of h is λ 1 /4, thereby significantly reducing the value of h. In this case, for the first RF signal, the distance between the resonant structure  230  and the radiation surface of the antenna module  100  is the minimum distance. When the first RF signal is at 28 GHz, the distance from the resonant structure  230  to the antenna module  100  is about 5.35 mm. 
     Further, a maximum value D max  of a directivity coefficient of the antenna module  100  satisfies: 
     
       
         
           
             
               
                 D 
                 max 
               
               = 
               
                 
                   1 
                   + 
                   
                     R 
                     1 
                   
                 
                 
                   1 
                   - 
                   
                     R 
                     1 
                   
                 
               
             
             , 
           
         
       
     
     where R 1 =S 11   2 , and S 11  represents an amplitude of a reflection coefficient of the antenna radome  200  to the first RF signal. When the directivity coefficient of the antenna module  100  has the maximum value, the first RF signal has the best directivity. 
     Further, the preset frequency band at least includes a full frequency band of 3GPP mmWave. 
     Reference can be made to  FIG. 34 , which illustrates reflection coefficient S 11  curves corresponding to substrates with different dielectric constants. In this implementation, simulation of the substrate  210  having a thickness of 0.55 mm is carried out. In this schematic diagram, a horizontal axis represents a frequency in units of GHz, and a vertical axis represents a reflection coefficient in units of decibel (dB). In this schematic diagram, curve {circle around (1)} is a variation curve of a reflection coefficient S 11  with a frequency when the substrate  210  has a dielectric constant of 3.5, curve {circle around (2)} is a variation curve of the reflection coefficient S 11  with the frequency when the substrate  210  has the dielectric constant of 6.8, curve {circle around (3)} is a variation curve of the reflection coefficient S 11  with the frequency when the substrate  210  has the dielectric constant of 10.9, curve {circle around (4)} is a variation curve of the reflection coefficient S 11  with the frequency when the substrate  210  has the dielectric constant of 25, curve {circle around (5)} is a variation curve of the reflection coefficient S 11  with the frequency when the substrate  210  has the dielectric constant of 36. It can be seen from this schematic diagram that reflection coefficients S 11  of the substrates  210  with different dielectric constants are generally relatively constant. 
     Reference is made to  FIG. 35 , which illustrates reflection phases corresponding to an RF signal of 28 GHz in reflection phase curves corresponding to substrates with different dielectric constants. In this implementation, simulation of the substrate  210  having a thickness of 0.55 mm is carried out. In this schematic diagram, a horizontal axis represents a frequency in units of GHz, and a vertical axis represents a phase in units of degree (deg). In this schematic diagram, curve {circle around (1)} is a variation curve of a reflection phase with the frequency when the substrate  210  has a dielectric constant of 3.5, curve {circle around (2)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 6.8, curve {circle around (3)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 10.9, curve {circle around (4)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 25, curve {circle around (5)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 36. In this schematic diagram, when the frequency is 28 GHz, the reflection phase corresponding to each curve falls within the range of −90° ˜−180° 0  or 90° ˜180°. That is, the dielectric substrates  210  with different dielectric constants do not satisfy the in-phase reflection characteristics to the RF signal of 28 GHz. 
     Reference is made to  FIG. 36 , which illustrates reflection phases corresponding to an RF signal of 39 GHz in reflection phase curves corresponding to substrates with different dielectric constants. In this implementation, simulation of the substrate  210  having a thickness of 0.55 mm is carried out. In this schematic diagram, a horizontal axis represents a frequency in units of GHz, and a vertical axis represents a phase in units of degree (deg). In this schematic diagram, curve {circle around (1)} is a variation curve of a reflection phase with the frequency when the substrate  210  has a dielectric constant of 3.5, curve {circle around (2)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 6.8, curve {circle around (3)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 10.9, curve {circle around (4)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 25, curve {circle around (5)} is a variation curve of the reflection phase with the frequency when the substrate  210  has the dielectric constant of 36. In this schematic diagram, when the frequency is 39 GHz, the reflection phase corresponding to each curve falls within the range of −90° ˜−180° 0  or 90° ˜180°. That is, the dielectric substrates  210  with different dielectric constants do not satisfy the in-phase reflection characteristics to the RF signal of 39 GHz. 
     Reference is made to  FIG. 37 , which is a schematic diagram illustrating curves of reflection coefficient S 11  and transmission coefficient S 12  of an antenna radome provided in the present disclosure. In this schematic diagram, a horizontal axis represents a frequency in units of GHz, and a vertical axis represents a phase in units of dB. In this schematic diagram, curve {circle around (1)} is a variation curve of a reflection phase with the frequency, curve {circle around (2)} is a variation curve of a reflection phase with the frequency. In this schematic diagram, for RF signals of 28 GHz and 39 GHz, the transmission coefficient is relatively large and the reflection coefficient is relatively small. That is, the RF signals of 28 GHz and 39 GHz can better pass through the antenna radome  200  provided in the present disclosure, and thus a relatively high transmittance can be achieved. 
     Reference is made to  FIG. 38 , which is a schematic diagram illustrating a reflection phase curve of an antenna radome provided in the present disclosure. In this schematic diagram, a horizontal axis represents a frequency in units of GHz, and a vertical axis represents a phase in units of degree (deg). It can be seen from this diagram that at a frequency of 28 GHz, a difference between the reflection phase and the incident phase is approximately zero, which satisfies the in-phase reflection characteristics. For each frequency point in band n261 (27.5 GHz˜28.35 GHz), the difference between the reflection phase and the incident phase is in the range of −90° ˜+90°, that is, the antenna radome  200  has the in-phase reflection characteristics in band n261. For each frequency point in the band n260 (37 GHz˜40 GHz), the difference between the reflection phase and the incident phase is in the range of −90° ˜+90°, that is, the antenna radome  200  has the in-phase reflection characteristics in band n260. 
     Reference is made to  FIG. 39 , which is a directional pattern at 28 GHz and 39 GHz of an antenna radome provided in the present disclosure. The length of the line segment of the center line of the radiation surface of the antenna module  100  from the radiation surface to the surface of the resonant structure  230  facing the antenna module  100  is equal to 2.62 mm (that is, equivalent to a quarter of a wavelength of an RF signal of 28 GHz which propagates in air) is taken as an example for simulation. As can be seen from the pattern of the antenna radome  200  at 28 GHz, the maximum value is 11.7 dBi in the pattern, that is, the gain of the antenna module  100  at 28 GHz is 11.7 dBi, and the antenna module  100  has a relatively large gain at 28 GHz. As can be seen from the pattern of the antenna radome  200  at 39 GHz, the maximum value is 12.2 dBi in the pattern, that is, the gain of the antenna module  100  at 28 GHz is 12.2 dBi, and the antenna module  100  has a relatively large gain at 39 GHz. 
     An electronic device  1  is further provided in the present disclosure. Reference is made to  FIG. 40 , which is a circuit block diagram of an electronic device provided in an implementation of the present disclosure. The electronic device  1  includes a controller  30  and an antenna apparatus  10 . The antenna apparatus  10  refers to the foregoing description, which will not be repeated herein. The antenna apparatus  10  is electrically connected with the controller  30 . The antenna module  100  in the antenna apparatus  10  is configured to emit a first RF signal and a second RF signal under control of the controller  30 . 
     Reference is made to  FIG. 41 , which is a schematic structural view of an electronic device provided in an implementation of the present disclosure. The electronic device  1  includes a battery cover  50 . The substrate  210  at least includes the battery cover  50 . A relationship between the resonant structure  230  and the battery cover  50  can refer to a position relationship between the resonant structure  230  and the foregoing substrate  210 , and the substrate  210  described above needs to be replaced with the battery cover  50 . For example, the resonant structure  230  can be directly disposed on an inner surface of the battery cover  50 ; or the resonant structure  230  is attached to the inner surface of the battery cover  50  via a carrier film  220 ; or the resonant structure  230  is directly disposed on an outer surface of the battery cover  50 ; or the resonant structure  230  is attached to the outer surface of the battery cover  50  via a carrier film  220 ; or part of the resonant structure  230  is disposed on the inner surface of the battery cover  50 , and part of the resonant structure  230  is disposed on the outer surface of the battery cover  50 ; or the resonant structure  230  is partially embedded in the battery cover  50 . Part of the resonant structure  230  can be disposed on the inner surface of the battery cover  50  as follows: the part of the resonant structure  230  is directly disposed on the inner surface, or the part of the resonant structure  230  is disposed on the inner surface via the carrier film  220 . Part of the resonant structure  230  can be disposed on the outer surface of the battery cover  50  as follows: the part of the resonant structure  230  is directly disposed on the outer surface of the battery cover  50 , or the part of the resonant structure  230  is disposed on the outer surface of the battery cover  50  via the carrier film  220 . 
     The battery cover  50  generally includes a back plate  510  and a frame  520  bent and connected to a periphery of the back plate  510 . The resonant structure  230  may be disposed corresponding to the back plate  510  or corresponding to the frame  520 . In this implementation, for example, the resonant structure  230  is disposed corresponding to the back plate  510 . 
     Furthermore, the electronic device  1  in this implementations, also includes a screen  70 . The screen  70  is disposed at an opening of the battery cover  50 . The screen  70  is configured to display texts, images, videos, etc. 
     Reference is made to  FIG. 42 , which is a schematic structural view illustrating an electronic device provided in an implementation of the present disclosure. The electronic device  1  further includes a screen  70 , the substrate  210  at least includes the screen  70 , the screen  70  includes a cover plate  710  and a display module  730  stacked with the cover plate  710 , and the resonant structure  230  is located between the cover plate  710  and the display module  730 . The display module  730  may be, but is not limited to, a liquid display module, or an organic light-emitting diode (OLED) display module, correspondingly, the screen  70  may be, but is not limited to, a liquid display screen or an OLED display screen. Generally, the display module  730  and the cover plate  710  are separate modules in the screen  70 , and the resonant structure  230  is disposed between the cover plate  710  and the display module  730 , which can reduce a difficulty of integrating the resonant structure  230  into the screen  70 . 
     Furthermore, the electronic device  1  also includes a battery cover  50 , and the screen  70  is disposed on an opening of the battery cover  50 . Generally, the battery cover  50  includes a back plate  510  and a frame  520  bendably connected with a periphery of the back plate  510 . 
     In an implementation, the resonant structure  230  is located on the surface of the cover plate  710  facing the display module  730 . The resonant structure  230  is located on the surface of the cover plate  710  facing the display module  730 , which can reduce difficulty of forming the resonant structure  230  on the cover plate  710 , compared to the resonant structure  230  being disposed in the display module  730 . 
     Although the implementations of the present disclosure have been shown and described above, it can be understood that the above implementations are exemplary and cannot be understood as limitations to the present disclosure. Those of ordinary skill in the art can change, amend, replace, and modify the above implementations within the scope of the present disclosure, and these modifications and improvements are also regarded as the protection scope of the present disclosure.