Premium
Compact planar multiple‐input‐multiple‐output antenna with pattern diversity based on the complementary theory
Author(s) -
Xu Yizhen,
Wen Sichao,
Dong Yuandan
Publication year - 2021
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.32966
Subject(s) - dipole antenna , physics , radiation pattern , ground plane , stub (electronics) , mimo , optics , electrical engineering , acoustics , electronic engineering , antenna (radio) , engineering , channel (broadcasting)
A three‐port planar multiple‐input‐multiple‐output (MIMO) antenna system with pattern diversity based on the complementary theory is presented in this letter. Three directional antennas without any directors or reflectors are introduced as the radiating elements, which are rotationally symmetrical and sharing a small ground. The unilateral radiation pattern is achieved for each antenna element based on the complementary theory, where an electric dipole and a magnetic dipole are placed orthogonally and excited simultaneously. An inverted L‐shaped stub is used as the electric dipole. A capacitively loaded loop operated on the zeroth‐order resonant mode is applied as the equivalent magnetic dipole. The capacitive loading is realized with six periodical interdigital left‐handed series capacitors. Furthermore, a defected ground structure between each two ports is adopted to further improve the isolation. The operation mechanism of the proposed MIMO antenna is discussed and experimentally verified. The proposed MIMO antenna system has a measured fractional bandwidth of 7.2% (3.33–3.58 GHz) with |S11| < −10 dB. The port isolation is better than 15 dB and the envelope correlation coefficient is less than 0.0234 in the operation band.