Decoupling of Two Strongly Coupled Dual-Band Antennas With Reactively Loaded Dummy Element Array

An efficient antenna mutual coupling reduction (decoupling) technique using reactively loaded dummy element array for two dual-band closely coupled MIMO antennas is proposed in this paper. This dummy element array comprises three dummy elements, including one low-frequency dummy element and two symmetrically placed high-frequency dummy elements. A pair of dual-band antennas working at 2.45 GHz (low band) and 5.8 GHz (high band) simultaneously is used to demonstrate the effectiveness of the proposed method and to illustrate the decoupling design process. The dual-band antennas with and without the designed dummy element array are both fabricated and measured. Measurement results show good impedance matching for both antenna ports at both operating bandwidths. More importantly, the isolations have been improved from 9 dB at low band and 7.7 dB at high band to more than 20 dB at low band and more than 25 dB at high band, respectively. The envelop correlation coefficient (ECC) as one key figure of merits for MIMO antennas is also improved significantly. The proposed method can find plenty of applications in dual-band wireless systems where multiple antennas are installed.