Patent Publication Number: US-2009237315-A1

Title: Multi-input, multi-output antenna device

Description:
BACKGROUND OF THE INVENTION 
     (a) Field of the Invention 
     The invention is related to an improvement on antenna device, more particularly to a multi-input, multi-output antenna applicable to be mounted on electrical appliances for multi-input, multi-output (MIMO) use. 
     (b) Description of the Prior Art 
     The multi-input, multi-output (MIMO) technology is a radio transmission technology which is through multiple individually independent antennas to emit signals at the emitting end, and multiple antennas to receive and recover the original message at the receiving end simultaneously. The core technology concept is meant to utilize the space degree of freedoms offered by said multiple emitting antennas and said multiple receiving antennas to effectively promote the spectrum of radio communication system and transmission rate in order to improve the communication quality, so that system data throughput and transmission distance can be greatly increased while without increasing bandwidth or total transmit power expenditure. 
     An antenna device as shown in  FIG. 1A  is to be mounted on electrical appliances for multi-input, multi-output technology use, said antenna device mainly comprises two dipole antennas  10  for receiving and transmitting signals respectively, wherein as shown in  FIG. 1B , one dipole antenna is represented by a solid line, while the other dipole antenna is represented by a dashed line, whereas said two dipole antennas  10  have the same frequency with small negative values, and further with poor isolation, the signals are easy mutually interfered thereby affecting signal reception quality of the whole antenna and electrical appliances. 
     SUMMARY OF THE INVENTION 
     In view of this, the invention is to improve the aforesaid disclosed conventional antenna device, particularly to provide a multi-input, multi-output antenna device applicable to be mounted on electrical appliances for multi-input, multi-output (MIMO) use. 
     To achieve above disclosed purpose, the antenna device of the invention mainly comprises a dipole antenna and a slot antenna for receiving and transmitting signals, wherein said slot antenna has at least one metal flat plate of L type section, said metal flat plate is formed with a bending at middle section, two ends of the bending are respectively made to a vertically extended vertical section and a horizontally extended horizontal section, and said metal flat plate is made with a slot which is connected through between vertical and horizontal sections, thereby constituting a multi-input, multi-output antenna device to be able to effectively segregate receiving and transmission frequencies without signal interferences. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a structural schematic view of a conventional antenna device. 
         FIG. 1B  shows the reflection loss and voltage standing wave ratio (VSWR) of two conventional dipole antennas. 
         FIG. 2A  is a structural schematic view of the antenna device of the invention. 
         FIG. 2B  shows the reflection loss and voltage standing wave ratio (VSWR) of the dipole antenna and slot antenna in the first embodiment of the invention. 
         FIG. 2C  shows the reflection loss and voltage standing wave ratio (VSWR) of the dipole antenna and slot antenna in the second embodiment of the invention. 
         FIG. 3  is a structural view showing the outlook of the slot antenna in the first embodiment of the invention. 
         FIG. 4  is a cross-sectional view of the slot antenna in the first embodiment of the invention. 
         FIG. 5  is another structural view showing the outlook of the slot antenna in the first embodiment of the invention. 
         FIG. 6  is a structural view showing the outlook of the slot antenna in the second embodiment of the invention 
         FIG. 7  is a structural decomposition view of the slot antenna in the second embodiment of the invention. 
         FIG. 8  is a structural cross-sectional view of the slot antenna in the second embodiment of the invention. 
         FIG. 9  is another structural view showing the outlook of the slot antenna in the second embodiment of the invention. 
         FIG. 10A  shows the radiation field distribution measured at 2.45 GHZ frequency for the slot antenna in the first embodiment of the invention. 
         FIG. 10B  shows the radiation field distribution measured at 2.45 GHZ frequency for the slot antenna in the second embodiment of the invention 
     
    
    
     DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     As shown in  FIG. 2A , the antenna device of the invention comprises: a dipole antenna  10  and a slot antenna  20  which are respectively used for receiving and transmitting signals, wherein said slot antenna has at least one metal flat plate of L type section. Simultaneously referring to the first embodiment shown in  FIG. 3  and  FIG. 4 , wherein slot antenna  20  is a metal flat plate of L type section  21  being made with a slot hole  213  thereon and being formed with a bending at middle section thereof, and two ends of said bending are respectively made to a vertically extended vertical section  211  and a horizontally extended horizontal section  212 . 
     Said slot  213  of slot antenna  20  is connected through between vertical section  211  and horizontal section  212 , thereby allowing one end of metal flat plate  21  to be used as the feed-in point for electrical connection with transmission wire  30 . Further, as shown in  FIG. 5 , perimeter of slot  213  can be changed through changing the length of metal flat plate  21  to be matchingly used as a high frequency antenna (shorter slot perimeter) or low frequency antenna (longer slot perimeter). 
     As said dipole antenna and slot antenna of the invention are for receiving and transmission signals use, the reflection loss and voltage standing wave ratio (VSWR) of the dipole antenna and slot antenna are shown in  FIG. 2B , wherein dipole antenna is represented by a solid line, and slot antenna in the first embodiment is represented by a dashed line, hence, as illustrated by the Fig., said dipole antenna and slot antenna can effectively segregate the receiving and transmission frequencies without causing signal interference due to the relatively larger cathode for better isolation, thereby constituting a multi-input, multi-output antenna device especially suitable for multi-input, multi-output (MIMO) use. 
     Furthermore, as shown by the second embodiment in  FIGS. 6 to 8 , said slot antenna  20  is constituted by two metal flat plates of L type sections  21  being mutually coveredly connected by welding, and each metal flat plate  21  is made with a slot  213  thereon and formed with a bending at middle section thereof, two ends of said bending are respectively made to a vertically extended vertical section  211  and a horizontally extended horizontal section  212 . 
     Said slot  213  of each metal flat plate  21  is connected through between vertical section  211  and horizontal section  212 , thereby allowing one end of one metal flat plate  21  to be used as the feed-in point for electrical connection with transmission wire  30 . Further, as shown in  FIG. 9 , perimeter of slot  213  can be changed through changing the length of metal flat plate  21  to be matchingly used as a high frequency antenna (shorter slot perimeter) or low frequency antenna (longer slot perimeter) 
     As said dipole antenna and slot antenna of the invention are for receiving and transmission signals use, the reflection loss and voltage standing wave ratio(VSWR) of the dipole antenna and slot antenna are shown in  FIG. 2C , wherein dipole antenna is represented by a solid line, and slot antenna in the second embodiment is represented by a dashed line, hence, as illustrated by the Fig., said dipole antenna and slot antenna can effectively segregate the receiving and transmission frequencies without causing signal interference due to the relatively larger cathode for better isolation, thereby constituting a multi-input, multi-output antenna device especially suitable for multi-input, multi-output(MIMO) use. 
     Additionally,  FIG. 10A ,  10 B show the radiation field distributions measured at 2.45 GHZ frequency for said slot antenna of single slot in the first embodiment and said slot antenna of double slots in the second embodiment, wherein as shown in the Figs., said slot antenna of a single slot has a better directivity while said slot antenna of double slots has a better omni-directivity. 
     As summarized from above descriptions, the invention discloses a better and more practical multi-input, multi-output antenna device, hence it is applied for new type patent according to law. Further, as the contents and characteristics of the art has been disclosed above, while substitutions and modifications may be performed by those skilled in the art without deviating from the spirit of the invention due to disclosure of the invention. For this reason, scope of protection for this invention shall not be limited to the disclosed embodiments only, but shall also include the various substitutions and modifications without deviating from the spirit of the invention, and shall be covered by the scope of claims herein.