Multi-input multi-output antenna with multi-band characteristic
The present invention relates to a multi-input multi-output (MIMO) antenna with a multi-band characteristic which includes a plurality of MIMO antenna, each having a pair of antenna elements, to support multiple bands, and is capable of guaranteeing high antenna efficiency for different bands by minimizing an interference between antenna elements of each MIMO antenna to improve an isolation characteristic. The MIMO antenna system having a multi-band characteristic, which includes two pairs of antenna patterns to support different band and coupling antenna parts separated from and coupled with the pairs of antenna patterns, can improve an isolation through the coupling antenna parts and guarantee an antenna gain. Moreover, since signal interference caused by the coupling effect can be cancelled to guarantee a band width with no change in antenna characteristics, it is possible to constructing two or more antennas to support a multi-band while guaranteeing stable operation of the antennas.
1. A MIMO antenna system having a multi-band characteristic, comprising:
a circuit board including two pairs of power feeders;
a pair of carriers arranged in both sides of the circuit board;
a first antenna pattern corresponding to a first band and a second antenna pattern corresponding to a second band, which are connected to the power feeders and are formed in one of the carriers;
a third antenna pattern corresponding to the first band and a fourth antenna pattern corresponding to the second band, which are connected to the power feeders and are formed in the other carrier; and
a first coupling antenna part which is formed in the one carrier and operates with the first band and a second coupling antenna part which is formed on the other carrier and operates with the second band, the first and second coupling antenna parts being separated from each other on the carriers on which the antenna patterns are formed.
2. The MIMO antenna system according to claim 1 , wherein the system uses wireless communication of LTE or Wibro (or Mobile WiMAX) and is accommodated in an antenna box including connectors for supplying current into the power feeders.
3. The MIMO antenna system according to claim 1 , wherein the first band has a resonance frequency two times or more as high as that of the second band.
4. The MIMO antenna system according to claim 1 , wherein at least one of the first and second coupling antenna parts includes an extension which faces the other coupling antenna part and performs a stub function.
5. The MIMO antenna system according to claim 1 , wherein at least one of the first and second coupling antenna parts includes a closed loop.
6. The MIMO antenna system according to claim 1 , wherein each of the first to fourth antenna patterns has a length of λ/4.
7. The MIMO antenna system according to claim 1 , wherein each of the first and second antenna parts has a length of λ/2.