Mimo antenna
Technical field
The present invention relates to field of antenna, particularly relate to a kind of mimo antenna.
Background technology
Along with developing rapidly of radio communication, people are more and more higher to the requirement of radio communication.Application multi-antenna technology can improve efficiency of transmission and the reliability of radio communication, wherein MIMO (MultipleInputMultipleOutput, multiple-input and multiple-output) system launches the signal of different frequency bands by the multiple antennas framework of himself transmitting terminal, receives the signal of different frequency bands at receiving terminal also through multiple antennas framework.But, various signals that are that the framework of multiple antennas is launched or that receive often interfere, and not only affect the degree of association of signal, will also result in the decline of signal transmission rate.And the degree of association of signal often with scattering parameter S12 (isolation) positive correlation.
According to prior art, the spacing between multiple antennas is only more than the half of signal wavelength, and its isolation can be only achieved below-20dB, but, in the most compact wireless communications products, the previously used distance between antenna is much smaller than the half of signal wavelength, it is impossible to reach required insulated degree requirement.
Summary of the invention
In view of this, it is necessary to provide MIMO (MultipleInputMultipleOutput, the multiple-input and multiple-output) antenna of a kind of miniaturization, to improve isolation between antennae, reduce interfering between each radiating element in mimo antenna, thus improve the usefulness of mimo system.
A kind of mimo antenna that embodiment of the present invention provides includes: the first radiating element, the second radiating element and connecting portion.Wherein, connecting portion is connected between the first radiating element and the second radiating element;The isolation channel in " H " font it is provided with above connecting portion and between the first radiating element and the second radiating element.
Preferably, the first radiating element and the second radiating element are all PIFA antenna.
Preferably, mimo antenna also includes grounding parts.Grounding parts is connected to ground, and is all not connected to the first radiating element, the second radiating element and connecting portion.
Preferably, connecting portion is contained in the lower half of isolation channel.
Preferably, connecting portion is in " ㄇ " shape.
Preferably, the first radiating element and the second radiating element all include kink and Department of Radiation, and wherein, kink is a band square box jaggy, and Department of Radiation is contained in kink.
Preferably, Department of Radiation is in falling " F " font, and the middle part of Department of Radiation is wedge shaped.
Preferably, the end in the middle part of Department of Radiation is the load point of mimo antenna.
Preferably, the kink of the first radiating element is connected with the first end of connecting portion by short microstrip line, and the kink of the second radiating element is connected with the second end of connecting portion by another short microstrip line.
The better performances of mimo antenna of the present invention, its antenna volume is the least, it is adaptable in compact product design.
Accompanying drawing explanation
Fig. 1 is the structural representation of mimo antenna the first embodiment of the present invention.
Fig. 2 is the structural representation of mimo antenna the second embodiment of the present invention.
Fig. 3 is the multiport circuit figure of mimo antenna the second embodiment of the present invention.
Main element symbol description
First radiating element A1
Second radiating element A2
Connecting portion B
Kink C
Grounding parts G
Load point P
Department of Radiation R
Short microstrip line S
Isolation channel Slot
Substrate 10
Following detailed description of the invention will further illustrate the present invention in conjunction with above-mentioned accompanying drawing.
Detailed description of the invention
In order to preferably describe the mimo antenna of the present invention, shadow regions different in Figure of description is for representing the different ingredients of mimo antenna.
Refer to the structural representation that Fig. 1, Fig. 1 are MIMO of the present invention (MultipleInputMultipleOutput, multiple-input and multiple-output) antenna the first embodiment.
In the present embodiment, mimo antenna is a printed antenna, is arranged at the surface of substrate 10, and dash area represents the metal level that the materials such as Copper Foil are formed.Mimo antenna includes the first radiating element A1, the second radiating element A2 and connecting portion B.
Wherein, the first radiating element A1 and the second radiating element A2 is all used for radiating or receiving electromagnetic wave signal, and in the present embodiment, the first radiating element A1 and the second radiating element A2 may be designed to unipole antenna, slot antenna etc., and this is not restricted.
Connecting portion B is connected between the first radiating element A1 and the second radiating element A2.The isolation channel Slot in " H " font it is provided with above connecting portion B and between the first radiating element A1 and the second radiating element A2.
In the isolation channel Slot arranged, the region of " H " font is all hollow area.Actual fabrication when, it is possible to use perforation or the mode hollowed out, it is through to, from a surface of substrate 10, another surface that this surface is relative, to form the hollow area of one " H " font.The one isolation channel Slot in " H " font is set between the first radiating element A1 and the second radiating element A2, the isolation between two radiating elements can be effectively improved.
Mimo antenna also includes that grounding parts G, grounding parts G are connected to ground, and is all not connected to the first radiating element A1, the second radiating element A2 and connecting portion B.In the first radiating element A1, the lower section of the second radiating element A2, i.e. first radiating element A1, the second radiating element A2 are respectively arranged with a load point P near the side of grounding parts G, with the corresponding electromagnetic wave signal of feed-in, the electromagnetic wave signal of frequency range 2.4GHz-2.5GHz can be respectively fed into such as two load point P and feed-in frequency range is the electromagnetic wave signal of 4.9GHz-5.8GHz.
Refer to the structural representation that Fig. 2, Fig. 2 are mimo antenna the second embodiment of the present invention.
In this second embodiment, mimo antenna also includes the first radiating element A1 as described in the first embodiment, the second radiating element A2, connecting portion B and grounding parts G.The isolation channel Slot in " H " font it is provided with above connecting portion B and between the first radiating element A1 and the second radiating element A2.Connecting portion B, in " ㄇ " shape, is contained in " ㄇ " shape semi-surrounding region that isolation channel Slot lower half is formed.
Additionally, in this second embodiment, the first radiating element A1 and the second radiating element A2 can be all that the PIFA antenna being symmetricly set on connecting portion B both sides, the first radiating element A1 and the second radiating element A2 all include: kink C and Department of Radiation R.As a example by the first radiating element A1, kink C is a band square box jaggy, and Department of Radiation R is in falling " F " font, and the middle part of Department of Radiation R is wedge shaped, and Department of Radiation R is contained in kink C.Near the load point P that side (i.e. end in the middle part of Department of Radiation R) is mimo antenna of grounding parts G in the middle part of Department of Radiation R, for the electromagnetic wave signal of the different frequency range described in feed-in the first embodiment.
The kink C of the first radiating element A1 is connected by first end of short microstrip line S and connecting portion B, and the kink C of the second radiating element A2 is connected by second end of another short microstrip line S and connecting portion B.
In other embodiments, the first radiating element A1 and the second radiating element A2 can be other kinds of flat plane antenna, kink C and Department of Radiation R can also be other shapes, this is not restricted.
Refer to the multiport circuit figure that Fig. 3, Fig. 3 are mimo antenna the second embodiment of the present invention.
Curve a in Fig. 3 is for representing the return loss between the first radiating element A1 and the second radiating element A2, and curve b is for representing the isolation between the first radiating element A1 and the second radiating element A2.According to Fig. 3, the mimo antenna of this case design, in the frequency range near 2.5GHz, its isolation is less than-20dB, meets Antenna Design requirement.
The mimo antenna of present invention design, the isolation between its radiating element is preferable, it is possible to increase the degree of association of radiation signal and the usefulness of mimo system, it is adaptable in the design application of various mimo systems.