Journal of electromagnetic engineering and science

The Korean Institute of Electromagnetic Engineering and Science (한국전자파학회)
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Miniaturized Radio Frequency Choke Using Modified Stubs for High Isolation in MIMO Systems

  • Lim, Seonho (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Choi, Woo Cheol (Department of Electrical and Electronic Engineering, Yonsei University) ;
  • Yoon, Young Joong (Department of Electrical and Electronic Engineering, Yonsei University)
  • Received : 2015.06.22
  • Accepted : 2015.10.12
  • Published : 2015.10.31
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Abstract

In this paper, a miniaturized radio frequency choke (RFC) using modified stubs is proposed to improve isolation characteristics in a multiple-input-multiple-output (MIMO) antenna system. The proposed RFC, based on the LC resonance, is designed to suppress the leakage current that leads to the degradation of antenna diversity performances in the MIMO antenna configuration. The proposed RFC is composed of two open stubs that are implemented on the top of the ground plane and miniaturized by adding a slit structure on the ground plane. The MIMO antennas are also designed to verify isolation performance in the LTE 2300 band (2,300-2,400 MHz). The MIMO antennas perform well with low reflection coefficient characteristics and high isolation characteristics in the whole LTE 2300 band. To evaluate the isolation in the MIMO system, the envelope correlation coefficient (ECC) is calculated, and the value is less than 0.08. The achieved ECC is regarded as a reasonable result for improving isolation performance in the frequency range of 2,300-2,400 MHz; also, radiation patterns of antenna elements are maintained regardless of the presence of RFC.

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References

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