Patent Publication Number: US-11398669-B2

Title: Antenna arrangement for an electronic device

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. patent application Ser. No. 15/751,149, filed Feb. 7, 2018, which is a U.S. Nationalization of International Application No. PCT/US2016/042698, filed Jul. 18, 2016, which claims the benefit of Chinese Patent App. No. 201510484994.3, filed Aug. 7, 2015, the disclosures of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     An electronic device, such as a mobile phone, may include antenna arrangement to enable the electronic device to communicate with another device wirelessly. In a conventional antenna design, the antenna arrangement is provided within a housing of the electronic device. The antenna arrangement usually employs a Planar Inverted-F Antenna (PIFA) or a monopole antenna. However, the PIFA has drawbacks such as high demands on area and thickness, poor performance, etc.; and at the same time, the monopole antenna also suffers from poor performance since a big metal clearance is required. 
     Recently, a new antenna arrangement using metal rings as radiators becomes popular in wireless communication applications. Different from the conventional antenna design, the antenna arrangement uses a part of a metal frame of a wireless electronic device as antenna radiators. Generally, the antenna radiators require some slot cuttings and a direct feeding element which bridges a metal ring and radio frequency (RF) chipset. Such an antenna arrangement could provide an antenna design with a compact structure. However, the antenna performance could be substantially degraded during a call due to unintentional covering of the slots. At the same time, in the art, demands on a multi-antenna structure, a compact antenna design and low manufacturing cost are constantly increasing. 
     SUMMARY 
     In accordance with implementations of the subject matter described herein, a new antenna arrangement for an electronic device is proposed. 
     The antenna arrangement comprises a first antenna and a second antenna which can function separately or collaboratively. The first antenna includes a first metal section connected to a first grounding point and a first initial radiator for feeding first radiations to the first metal section. The second antenna includes a second metal section connected to a second grounding point and a second initial radiator for feeding second radiations to the second metal metal. The first metal section and the second metal section are both integral parts of a housing of the electronic device and separated by an opening. Furthermore, the second metal section is further connected to a third grounding point to provide isolation between the first antenna and the second antenna. Besides, other implementations also provide an electronic device comprising the antenna arrangement as described hereinabove and a method of manufacturing an antenna arrangement for an electronic device. With the implementations of the subject matter described herein, a pair of antennae can be built with the same one structure and, at the same time, a good antenna performance can be achieved. 
     It is to be understood that this Summary is provided to introduce a selection of concepts in a simplified form. The concepts are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically illustrates a block diagram of an electronic device in which one or more implementations of the subject matter described herein may be implemented; 
         FIG. 2  illustrates a schematic diagram of an antenna arrangement for an electronic device in accordance with one implementation of the subject matter described herein are implemented; 
         FIG. 3  illustrates another schematic diagram of an antenna arrangement for an electronic device in accordance with one implementation of the subject matter described herein; 
         FIG. 4  illustrates a schematic diagram of another antenna arrangement for an electronic device in accordance with another implementation of the subject matter described herein; 
         FIG. 5  illustrates a schematic diagram of an electronic device containing antenna arrangements in accordance with one implementation of the subject matter described herein; 
         FIGS. 6A to 6D  illustrate an example matching for an antenna arrangement and corresponding S-parameter and antenna efficiency in accordance with one implementation of the subject matter described herein; 
         FIGS. 7A to 7C  illustrate another example matching for an antenna arrangement and corresponding S-parameter and antenna efficiency in accordance with another implementation of the subject matter described herein; and 
         FIG. 8  schematically illustrates a flow chart of a method of manufacturing an antenna arrangement for an electronic device in accordance with one implementation of the subject matter described herein. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter described herein will now be discussed with reference to several example implementations. It should be understood these implementations are discussed only for the purpose of enabling those skilled persons in the art to better understand and thus implement the subject matter described herein, rather than suggesting any limitations on the scope of the subject matter. 
     As used herein, the term “includes” and its variants are to be read as open terms that mean “includes, but is not limited to.” The term “or” is to be read as “and/or” unless the context clearly indicates otherwise. The term “based on” is to be read as “based at least in part on.” The term “one implementation” and “an implementation” are to be read as “at least one implementation.” The term “another implementation” is to be read as “at least one other implementation.” Other definitions, explicit and implicit, may be included below. 
       FIG. 1  illustrates a block diagram of an electronic device  100  in accordance with an implementation of the subject matter described herein. The electronic device  100  may be a mobile device, such as a smart phone. However, it is to be understood that any other types of electronic devices with wireless communication capability may also easily adopt one implementation of the subject matter described herein, such as a portable digital assistant (PDA), a pager, a mobile computer, a mobile TV, a game apparatus, a laptop, a tablet computer, a GPS device, and other types of electronic devices with a transmitter and receiver. 
     The electronic device  100  comprises one or more antennas  112  which can implement the subject matter described herein and is operable to communicate with the transmitter  114  and the receiver  116 . The electronic device  100  further comprises at least one controller  120 . It should be understood that the controller  120  comprises circuits or logic required to implement the functions of the electronic device  100 . For example, the controller  120  may comprise a digital signal processor, a microprocessor, an A/D converter, a D/A converter, and/or any other suitable circuits. The control and signal processing functions of the electronic device  100  are allocated in accordance with respective capabilities of these devices. 
     The electronic device  100  may further comprise a user interface, which, for example, may comprise a ringer  122 , a speaker  124 , a microphone  126 , a display  128 , and an input device  130  such as a keyboard and/or mouse, and all of the above devices are coupled to the controller  120 . The electronic device  100  may further comprise a camera module  136  for capturing static and/or dynamic images. 
     The electronic device  100  may further comprise a battery  134 , such as a vibrating battery set, for supplying power to various circuits required for operating the electronic device  100  and alternatively providing mechanical vibration as detectable output. In an implementation, the electronic device  100  may further comprise a user identification module (UIM)  138 . The UIM  138  is usually a memory device with a processor built in. The UIM  138  may for example comprise a subscriber identification module (SIM), a universal integrated circuit card (UICC), a universal user identification module (USIM), or a removable user identification module (R-UIM), etc. The UIM  138  may comprise a card connection detecting apparatus. 
     The electronic device  100  further comprises a memory. For example, the electronic device  100  may comprise a volatile memory  140 , for example, comprising a volatile random access memory (RAM) in a cache area for temporarily storing data. The electronic device  100  may further comprise another non-volatile memory  142  which may be embedded and/or movable. The non-volatile memory  142  may additionally or alternatively include for example, EEPROM and flash memory, etc. The memory  140  may store any item in the plurality of information segments and data used by the electronic device  100  so as to implement the functions of the electronic device  110 . For example, the memory may contain machine-executable instructions which, when executed, cause the controller  120  to implement various method. 
     It should be understood that the structural block diagram in  FIG. 1  is shown only for illustration purpose, without suggesting any limitations on the scope of the subject matter described herein. In some cases, some devices may be added or reduced as required. 
     As mentioned hereinbefore, the antenna arrangement with dual metal rings becomes popular since multiple antennae are needed in an electronic device such as a mobile device to support Long Term Evolvement (LTE). However, it also suffers from poor performance in some circumstances, especially when a user unintentionally covers the slots at which feed points are arranged. And at the same time, demands on a multi-antenna structure, a compact antenna design and low manufacturing cost are constantly increasing. In view of this, there is proposed a new antenna arrangement for an electronic device. In accordance with implementations of the subject matter described herein, two antennae are built with dual metal rings. In addition to a grounding point to which one of the metal rings is connected, the metal ring is further connected to another grounding point to provide isolation between the two antennae. Thus, a pair of antennae can be built with the same one structure and, at the same time, a good antenna performance can be achieved. Next, reference will be made to  FIGS. 2 to 8  to describe the solution as provided in the subject matter described herein in further detail. 
       FIGS. 2 and 3  respectively illustrate a schematic diagram of an antenna arrangement for an electronic device in a front view and another schematic diagram of the antenna arrangement in a back view in accordance with one implementation of the subject matter described herein. It shall be appreciated that a part of the electronic device such as a mobile phone is also shown to indicate an example arrangement of components of the antenna arrangement clearly; however it is shown only for illustration purposes, and it does not mean any limitation to the antenna arrangement. 
     As illustrated in  FIG. 2 , the antenna arrangement  200  comprises a first antenna  210  and a second antenna  220 . The first antenna  210  may be for example a Long Term Evolvement (LTE) main antenna which could cover a bandwidth ranging from for example about 690 MHz to 3.6 GHz. The second antenna  220  may be for example a MIMO antenna or a non-cellar antenna. As an example of non-cellar antenna, the second antenna  220  may be an antenna for Global Positioning System (GPS), Wireless Local Area Network (WLAN), Bluetooth, radio broadcast, etc. 
     As illustrated in  FIGS. 2 and 3 , in the first antenna  210 , a first metal section  211  is connected to a first grounding point  214 , and a first initial radiator  212  is connected to a first antenna feeding point  213 . The first initial radiator  212  is an initial radiator which generates first radiations and feeds them to the first metal section  211  via the first antenna feeding point  213 . Thus, the first metal section  211  will function as another radiator to generate the first radiations together with the first initial radiator  212 . The first metal section  211  is an integral part of a metal frame  250  of housing of the electronic device. The first metal section  211  can be also called as a metal ring, which may function as another radiator of the first antenna  210 . Specially, the first metal section  211  and the first initial radiator  212  are separated by an air/substrate gap d 1 . In such a way, power of the first initial radiator  212  can be coupled to the first metal section  211  via proximity coupling, which will be detailed hereinafter. 
     Similarly, in the second antenna  220 , a second metal section  221  is connected to a second grounding point  224 , and a second initial radiator  222  is connected to a second antenna feeding point  223 . The second initial radiator  222  is an initial radiator which generates second radiations and feeds them to the second metal section  221  via a second antenna feeding point  223 . Thus, the second metal section  221  will function as another radiator to generate the second radiations together with the second initial radiator  222 . The second metal section  221  is also an integral part of the metal frame  250  of the housing of the electronic device. Like the first metal section, the second metal section  221  can be also called as a metal ring and function as another radiator of the second antenna. Between the first metal section  211  and the second metal section  221 , there is provided an opening  230 . The opening  230  may be an opening for recharging the electronic device, an opening for receiving an earphone plug, or etc., which separates the first metal section  211  and the second metal section  221 . Particularly, the second metal section  221  is further connected to a third grounding point  225 . 
     By further arranging such a grounding point  225  in addition to the second grounding point  224 , it can provide isolation between the first antenna  210  and the second antenna  220 . Thus, a pair of antennae can be built with the same one structure and at the same time a good antenna performance can be achieved. Theoretically, the grounding point  225  can be located anywhere so far as it can provide a predetermined level of isolation. In practice, it may be located at a position spaced from the second grounding point  224  by a certain distance to provide the desired isolation. In the illustrated antenna arrangement, the third grounding point  225  is located at an of the second metal section  221  end far away from the first grounding point  224  to provide the desired isolation. 
     The second metal section  221  can be electrically connected to the third grounding point  225  by any suitable means. In the example arrangement as illustrated in  FIGS. 2 and 3 , the second metal section  221  is electrically connected to the third grounding point  225  through a strip line  226   a,  particularly a straight microstrip line (having a length of 7 mm to 12 mm for mobile devices), printed on a printed circuit board (PCB) within the electronic device. Particularly, one of ends of the strip line  226  is electrically connected to the second metal section  221  at a connection point  227  and the other end of the strip line  226  is electrically connected to the third grounding point  225 . Thus, the strip line  226  and the second metal section  221  can form a loop and the second metal section  221  is connected to the third grounding point  225  to provide the desired isolation. 
     Furthermore, there is a metal patch extension  226   b  extending from the strip line  226   a,  which is also printed in the PCB. The metal patch extension  226   b  is a metal patch which laterally extends from the strip line  226   a.  The metal patch extension  226  is about 5×10 mm 2  to 1×15 mm 2  and can form an antenna load. In such a way, it may reduce a demand on a length of the second metal section. Usually, to achieve an antenna arrangement with dual metal rings, it requires a predetermined metal ring length, for example 70 mm or even more and such a length will set limits on the miniaturization of the electronic device. However, in some implementations of the subject matter as described herein, the metal patch extension  226   b  functions as an antenna load for the second metal section  221  and thus a smaller length could also achieve the desired antenna arrangement. Thus, the original demand on the length of the second metal section could be reduced greatly. In other words, in such a case, the second metal section  221  may have a shorter length than the first metal section  211  by means of the metal patch extension  226   b.  For example, in one implementation of the subject matter as described herein, the second metal section  221  may be, for example, 10 mm shorter than the first metal section  211 . 
     This length difference could provide more advantageous in antenna design. For example, if the first metal section  211  and the second metal section  221  are arranged near a top of a screen of the electronic device, the first metal section  211  may be arranged at the right top side while the second metal section  221  may be located on the left top side. This is because for a right-handed user, he/she will hold the electronic device at the left side with four fingers except his/her thumb and these fingers will cover more area and that at the right side. Thus, the shorter second metal section  221  will remarkably reduce a possibility that the antenna arranged is covered by those fingers. For a left-handed user, this arrangement can be reversed, i.e., the first metal section  211  may be located at the left top side and the second metal section  221  may be located at the right top side. For another case in which the first and second metal sections  211 ,  221  are arranged near a bottom of a screen of the electronic device, the antenna arrangement can also be arranged based on the length difference between the first metal section  211  and the second metal section  221 . Therefore, it is clear that the length difference between the first metal section  211  and the second metal section  221  could provide additional benefits. 
     In addition, the metal patch extension  226   b  may also have another function, i.e., collecting power from the second initial radiator  222 , which means the second initial radiator  222  could feed second radiations to the second metal section  221  through the metal patch extension  226   b.  Particularly, the power of the second initial radiator  222  is coupled to the metal patch extension  226   a  via the antenna feeding point  223  by means of aperture/proximity coupling and then the power is in turn delivered to a loop formed by the strip line  226   a  and the second metal section  221 . 
       FIG. 4  also illustrates a schematic diagram of another antenna arrangement for an electronic device in accordance with another implementation of the subject matter described herein. In  FIG. 4 , the first antenna  410 , the second antenna  420  and relevant components including the first and second metal sections  411 ,  421 , the first and second initial radiators  412 ,  422 , the first and second feeding points  413 ,  423 , the first and second grounding points  414 ,  424 , the third grounding point  425  are identical to the first antenna  210 , the second antenna  220  and those corresponding components as illustrated in  FIGS. 2 and 3 . The difference lies in that the antenna arrangement  400  has a strip line  426   a  and metal patch extension  426   b  which are different from the strip lines  226   a  and a metal patch extension  226   b  as illustrated in  FIGS. 2 and 3 . Specifically, the strip line  426   a  is not a straight microstrip line between the second metal section  421  and the third grounding point  425  but a microstrip line making a detour around the metal patch extension  426  which is connected with the strip line  426   a  near the grounding point. By this means, the length of the loop formed by strip line  426   a  and the second metal section  421  can be further increased. 
     Further as illustrated in  FIGS. 2 and 3 , the first initial radiator  212  and the second initial radiator  222  are printed on a PCB within the electronic device. In the existing antenna design with dual metal rings, an initial radiator is provided as separate components and connected to the circuit board with a supporting bracket. This needs not only an additional radiator production process but also an additional assembly process, which both means additional costs. However, through printing the first initial radiator  212  and the second initial radiator  222  on the PCB, the two initial radiators can be produced during the production of the PCB without any additional antenna producing process and additional assembling process. Thus, the production cost of the initial radiators can be reduced substantially and can be even called as zero-cost. The first initial radiator  212  and the second initial radiator  222  may be for example strip lines printed on the PCB. As illustrated in  FIGS. 2 and 3 , the first metal section  212  and the second metal section  222  are both microstrip lines in an L-shape and can be printed on the same surface of the PCB (i.e., they are coplanar). The first initial radiator  212  and the second initial radiator  222  may have an area ranging from 1×20 mm 2  to 1×40 mm 2 . In one implementation of the subject matter as described herein, the size of the first and second initial radiator is about 1×21 mm 2 , which is several times smaller than the regular initial radiator. Therefore, such a design may facilitate the miniaturization of the electronic device. 
     The second initial radiator  222  and the metal patch extension  226   b  are not in coplanar with each other, which means that they can be printed on different surfaces of the printed circuit board. In other words, there is an air/substrate gap d 0  between them in z direction as illustrated. It can be understood that the metal patch extension  226   b  which is also printed on the PCB will cover a certain area of the PCB. Thus, due to the limited area, it is not easy to arrange the second initial radiator  222  at the same surface as the metal patch extension  226   b.  Thus, as illustrated in  FIG. 3 , the second initial radiator  222  and the metal patch extension  226   b  are printed on different surfaces of the PCB. For example, the second initial radiator  222  may be located on the top surface of the PCB together with the first initial radiator  212 , while the grounding connection  226  comprising the metal patch extension  226   b  may be located the bottom surface of the PCB. In such a case, the coupling between the second initial radiator  222  and the second metal section  226   b  could be obtained by means of an aperture coupling as illustrated in  FIG. 3  instead of a conventional direct connection. In other word, an aperture which goes through the PCB will be provided between the antenna feeding point  223  and the metal patch extension  226   b.  By utilizing the aperture coupling, it is possible to provide a desired coupling between the second metal section  221  and the second initial radiator  222  without using any physical feeding connection or using any feeding clips. In addition, the use of non-contact coupling will provide additional merits of reducing the required length of the second metal section. For example, in an implementation, the second metal section  221  may have a length of 50 mm, or even 40 mm long. In addition, the coupling between the second initial radiator and the metal patch extension may also be implemented by proximity coupling to achieve similar effects. 
     For the coupling between the first metal section and the first initial radiator, it is possible to obtain the coupling in many ways, for example, by a direct connection. However, in one implementation of the subject matter as described herein, it can be provided by a slot or proximity coupling. As illustrated in  FIGS. 2 and 3 , the first initial radiator  212  is printed on the PCB near the inner edge of a display chassis to provide a good proximity coupling. The gap d 1  between the PCB and the display chassis can range from, for example, 1.5 mm to 2.55 mm, and particularly can be 2 mm for example. By this means, it can achieve the desired coupling between the first metal section  211  and the first initial radiator  212  without any physical feed connection or feeding clips. Moreover, similarly, the use of non-contact coupling will provide an additional merit of reducing the required length of the first metal section. In an implementation, the first metal section  211  may have a length of 60 mm or even 50 mm. 
     The antenna arrangement as illustrated in  FIGS. 2 to 4  can be included in an electronic device such as mobile devices. For illustration purposes,  FIG. 5  illustrates a schematic diagram of an electronic device containing antenna arrangements in accordance with one implementation of the subject matter described herein. As illustrated in  FIG. 5 , the electronic device may comprise two antenna arrangements  500  and  500 ′ which are respectively arranged on the top and the bottom of display screen. The antenna arrangement  500  comprises a first antenna  510  and a second antenna  520  and the antenna arrangement  500 ′ comprises a first antenna  510 ′ and a second antenna  520 . The first antennae  510  and  510 ′ have a similar structure to the first antenna  210 ,  410  illustrated in  FIGS. 2 to 3  or  FIG. 4  and the second antennae  520  and  520 ′ have a similar structure to the second antenna  220 ,  420  as illustrated in  FIGS. 2 to 3  or  FIG. 4 . However, it shall be understood that although the electronic device is illustrated as including two antenna arrangements, it may also contain only one antenna arrangement or more than two. 
     It shall be understood that for an antenna arrangement, it is tough to meet the low band requirement when a 4G system is required in an electronic device such as mobile phone. The reason lies in that the antenna arrangement has to meet not only B5 &amp; B8 requirements for 2G and 3G systems but also B17, B13 and B20 (from 699 to 960 MHz) requirements. Usually, there is a big challenge for an antenna arrangement to cover such a wide bandwidth. In order to tackle this, a tuner or a single-pole-four-throw switcher (SP4T) can be used, which could provide different matching topologies to tune antenna resonant frequency, which might range from 690 MHz to 3.6 GHz for example. Hereinafter, several different matchings are described only for illustration purposes. 
       FIG. 6A  illustrates an example matching for the antenna arrangement in accordance with one implementation of the subject matter described herein. As illustrated in  FIG. 6A , the electronic device such as a mobile phone has matching circuits between the first feeding point  213  and the first initial radiator  212  and between the second feeding point  223  and the second initial radiator  222  for both the main antenna and the MIMO antenna. In each matching circuit, 4 lumped elements are used, including two capacitors C 1  and C 2  or C 1 ′ and C 2 ′ and two inductors L 1  and L 2  or L 1 ′ and L 2 ′ which are connected as illustrated in  FIG. 6A .  FIG. 6B and 6C  illustrate a corresponding S-parameter and antenna efficiency for the matching circuits as illustrated in  FIG. 6A . The curves as illustrated in  FIG. 6B and 6C  are obtained through a simulation based on the parameter values as shown in  FIG. 6A . From the S-parameter curves, it can be seen that with those matching circuits, the main antenna may cover both B5 &amp; B8 with 200 MHz bandwidth (800-1000 MHz), and LTE middle and high bands (about 1710-2690 MHz). Besides, the antenna efficiency curves show that at the low band, the antenna efficiency is about −3.0 dB; at the middle &amp; high bands ranging from 1.71 to 2.7 GHz, it is over −3 dB. At the same time, the MIMO antenna also achieved a good matching and radiation efficiency. At the low band, its bandwidth is about 200 MHz, ranging from 800 MHz to 1000 MHz, and at the high band it can cover a bandwidth from 1710 MHz to 2690 MHz. As the MIMO antenna can allow a 3 dB degradation in comparison to main antenna, its radiation efficiency could meet over −6 dB target in both frequency ranges, i.e., 800 MHz-1000 MHz and 1710 MHz to 2170 MHz, as shown in  FIG. 6C . 
     As shown in  FIG. 2 , the opening  230  is small in practice, about 10 mm or less. As two antennae for example, the main antenna and the MIMO antenna, are arranged with such a close distance, they will have very poor isolation not to meet certification standard. However,  FIG. 6D  illustrates a good isolation between main and MIMO antennas for the  FIG. 6A  case. Two antennas achieve −11 dB isolation to meet RF requirements. 
       FIG. 7A  shows another matching for the antenna arrangement and corresponding S-parameter and antenna efficiency in accordance with another implementation of the subject matter described herein. Different from  FIG. 6A , in  FIG. 7A , the second antenna&#39;s matching circuit is changed so that the antenna can function as a GPS &amp; WLAN combo antenna. Particularly, the matching circuit uses two inductors L 1 ′ and L 2 ′ and one capacitor C 1 ′. Thus, it may have two resonances around 1.57 GHz and 2.4 GHz. From curves as illustrated in  FIGS. 7B and 7C , it can be seen that with these matching circuits, the antenna pairs can both cover desired frequency bands and obtain a good isolation (below −15 dB) therebetween. 
     Although the specific matchings are described hereinbefore with reference to  FIG. 6A to 7C ; the subject matter as described herein is not limited thereto. In a real application, it may include tens or more of matching circuits with different parameters setting, which might enable the antenna arrangement to cover different frequency bandwidths, even covering from 690 MHz to 3.6 GHz. 
     In addition, there is also provided a solution for manufacturing an antenna arrangement for an electronic device, which will be described in detail with reference  FIG. 8 . 
       FIG. 8  illustrates a method of manufacturing an antenna arrangement for an electronic device in accordance with one implementation of the subject matter as described herein. As illustrated in  FIG. 8 , the method starts from step  810 , in which a housing of electronic device is provided. The housing may comprise a first metal section and a second metal section, which are integral parts of the housing and separated by an opening. In one implementation of the subject matter as described herein, the first metal section and the second metal section may be both parts of metal frame of the housing of the electronic device. 
     Then in step  820 , the first metal section and the second metal section are coupled to a first initial radiator and a second initial radiator respectively. The first metal section and the second metal section can be coupled to the first initial radiator and the second radiation in any suitable manner. Particularly, in one implementation of the subject matter as described herein, the coupling between the first metal section and the first initial radiator can be implemented via a proximity coupling, while the coupling between the second initial radiator and the second metal section may be implemented via an aperture/proximity coupling. Thus, the first metal section and the second metal sections can be made shorter. 
     In step  830 , the first metal section and the second metal section are connected to a first grounding point and a second grounding point respectively. The first grounding point and the second grounding point may be located at two opposite ends of the first and second metal sections, which are far away from each other. The couplings may be implemented by using two grounding clips. 
     Further, in step  840 , the second metal section is further connected to a third grounding point to provide isolation between a first antenna and a second antenna to be formed. The first antenna may comprise the first metal section and the first initial radiator, and the second antenna may comprise the second metal section and the second initial radiator. In one implementation of the subject matter as described herein, the third grounding point may be located at an end of the second metal section away from the second ground point so as to provide the desired isolation. 
     In one implementation of the subject matter as described herein, the method may further comprise providing a printed circuit board having a strip line printed thereon. The second metal section may be connected to the third grounding point through the strip line. On the PCB board, there is further printed a metal patch extension extending from the strip line. This metal patch extension may function as an antenna load, which will help to reduce a demand on a length of the second metal section. The second initial radiator may feed radiations to the second metal section through the metal patch extension. That is to say, the metal patch extension will collect power from the second initial radiator and feeds the power to the second metal section. 
     In an implementation of the subject matter as described herein, the stripe line may be a straight line between the third grounding point and the second metal section as illustrated in  FIGS. 2 and 3 . In another implementation of the subject matter as described herein, the strip line may also be a line making a detour around the metal patch extension as illustrated in  FIG. 4 . In addition, at least one of the first initial radiator and the second initial radiator can be printed on the printed circuit board. Instead of manufacturing the first and/or the second initial radiators in a separate process, they will be printed on the PCB, during the production of the PCB, which will provide a low-cost advantage. For example, the at least one of the first initial radiator and the second initial radiator is a strip line printed on the printed circuit board and has an area ranging from 1×20 mm 2  to 1×40 mm 2 . Moreover, the second initial radiator and the metal patch extension may be printed on different surfaces of the printed circuit board, which might provide a feasible and space saving antenna arrangement. 
     In one implementation of the subject matter as described, the first metal section is about 50 mm long and the second metal section is about 40 mm long. The first antenna may be a LTE main antenna which covers a bandwidth ranging from 690 MHz to 3.6 GHz, while the second antenna is an MIMO antenna or a non-cellular antenna. 
     In addition, in the subject matter described herein, there is also provided an electronic device comprising an antenna arrangement as described hereinbefore with reference to  FIGS. 2 to 7C . For a purpose of simplification, the detailed description of the electronic device will be not be elaborated herein, for details about these actions, reference may be made to the description with reference to  FIGS. 2 to 7C . 
     Hereinbefore, specific implementations of the subject matter as described herein have been described in detail; however, it should be appreciated that all of these implementations are presented only for illustration purpose and the subject matter as described herein are not limited thereto. In fact, from the teachings provided herein, the skilled in the art will conceive of various modifications or variations without departing the spirit of the subject matter described herein. For example, in implementations of the subject matter as descried herein, the first and second metal sections are described as integral parts of the metal frame of an electronic device; however the subject matter as described herein is not limited to this and is also possible to use other parts of the housing as the first and second metal sections, for example located on the backside of the electronic device. Besides, it is also possible to reverse functionalities of the first and second antennae  210  and  220 ; the first metal section may also use an aperture coupling and use the metal patch extension to reduce its length, just as proposed for the second metal section. The first initial radiator and the second initial radiator may be printed on different surface of the PCB and at the same time the first initial radiator and the metal patch extension can be printed on the same surface of the PCB. In addition, shapes of the first and second initial radiators can be different from that illustrated in  FIGS. 2 to 4  and the shape of the first initial radiator and the shape of the second initial radiator can be different from each other. Furthermore, the order of performing methods  800  can be changed unless the changing is forbidden due to attributes of steps. For example, step  820 ,  830  and  840  can be performed in an order different from that described with reference to  FIG. 8  since there is no need to set strict orders for them. It should be appreciated that all these modifications or variations should be included within the scope of the subject matter described herein and the scope of the subject matter described herein is only defined by the claims appended hereinafter. 
     For illustrative purposes, some example implementations of the subject matter described herein are listed below. 
     In one aspect, there is provided an antenna arrangement for an electronic device. The antenna arrangement comprises a first antenna with a first metal section connected to a first grounding point and a first initial radiator for feeding first radiations to the first metal section; and a second antenna with a second metal section connected to a second grounding point and a second initial radiator for feeding second radiations to the second metal section, wherein the first metal section and the second metal section are integral parts of a housing of the electronic device and separated by an opening, and wherein the second metal section is further connected to a third grounding point to provide isolation between the first antenna and the second antenna. 
     In one implementation, the third grounding point is located at an end of the second metal section away from the second grounding point. 
     In another implementation, the second metal section is coupled to the third grounding point through a strip line printed on a printed circuit board within the electronic device, and wherein a metal patch extension extends from the strip line to reduce a demand on a length of the second metal section. 
     In a further implementation, the second initial radiator feeds the second radiations to the second metal section through the metal patch extension. 
     In a still further implementation, the stripe line is a straight line between the third grounding point and the second metal section or a line making a detour around the metal patch extension. 
     In a yet further implementation, at least one of the first initial radiator and the second initial radiator is printed on the printed circuit board within the electronic device. 
     In one implementation, the second initial radiator and the metal patch extension are printed on different surfaces of the printed circuit board. 
     In another implementation, the first initial radiator is coupled to the first metal section via a proximity coupling, and/or wherein the second initial radiator is coupled to the second metal section via an aperture or proximity coupling. 
     In a further implementation, at least one of the first initial radiator and the second initial radiator is a strip line printed on the PCB and has an area ranging from 1×20 mm2 to 1×40 mm2. 
     In a still further implementation, the first metal section and the second metal section are parts of a metal frame of the housing of the electronic device, wherein the first metal section is about 40 mm long and the second metal section is about 50 mm long. 
     In a yet further implementation, the first antenna is a Long Term Evolvement (LTE) main antenna which covers a bandwidth ranging from 690 MHz to 3.6 GHz and wherein the second antenna is a Multiple-Input Multiple-Output (MIMO) antenna or a non-cellular antenna. 
     In another aspect, there is provided an electronic device comprising at least one antenna arrangement according to the one aspect as described immediately above. 
     In a further aspect, there is further provided a method of manufacturing an antenna arrangement for an electronic device. The method comprises: providing a housing of an electronic device, the housing comprising a first metal section and a second metal section which are integral parts of the housing and separated by an opening; coupling the first metal section and the second metal section to a first initial radiator and a second initial radiator respectively; connecting the first metal section and the second metal section to a first grounding point and a second grounding point respectively; and connecting the second metal section further to a third grounding point to provide isolation between a first antenna comprising the first metal section and the first initial radiator and a second antenna comprising the second metal section and the second initial radiator. 
     In one implementation, the third grounding point is located at an end of the second metal section away from the second grounding point. 
     In another implementation, the method further comprise: providing a printed circuit board having a strip line and a metal patch extension printed thereon, wherein the second metal section is connected to the third grounding point through the strip line, and wherein the metal patch extension extends from the strip line to reduce a demand on a length of the second metal section. 
     In a further implementation, the second initial radiator feeds radiations to the second metal section through the metal patch extension. 
     In a still further implementation, the stripe line is a straight line between the third grounding point and the second metal section or is a line making a detour around the metal patch extension. 
     In a yet further implementation, at least one of the first initial radiator and the second initial radiator is printed on the printed circuit board within the electronic device. 
     In one implementation, the second initial radiator and the metal patch extension are printed on different surfaces of the printed circuit board. 
     In another implementation, the first initial radiator is coupled to the first metal section via a proximity coupling, and/or wherein the second initial radiator is coupled to the second metal section via an aperture or proximity coupling. 
     In a further implementation, at least one of the first initial radiator and the second initial radiator is a strip line printed on the PCB and has an area ranging from 1×20 mm2 to 1×40 mm2. 
     In a still further implementation, the first metal section and the second metal section are parts of a metal frame of the housing of the electronic device, wherein the first metal section is about 40 mm long and the second metal section is about 40 mm long. 
     In a yet further implementation, the first antenna is a Long Term Evolvement (LTE) main antenna which covers a bandwidth ranging from 690 MHz to 3.6 GHz and wherein the second antenna is a Multiple-Input Multiple-Output (MIMO) antenna or a non-cellular antenna. 
     Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the subject matter described herein, but rather as descriptions of features that may be specific to particular implementations. Certain features that are described in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable sub-combination. 
     Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.