Design and implementation of a compact tri‐band four‐port multiple‐input‐multiple‐output antenna

In this paper, a low-profile compact multiple-input-multiple-output (MIMO) antenna is presented for 2.45, 3.5, and 4.4 GHz application bands. The prospective antenna element consists of an inset-fed square patch and a ground plane loaded with a modified-complementary electric-inductive-capacitive (m-CELC) resonator. In order to encounter the coupling current between antenna elements, hexagonal-shaped complementary split-ring resonators (HS-CSRRs) are etched in the ground plane of the proposed MIMO antenna. The measured peak isolation achieved is 47 dB, with an edge-to-edge spacing of 0.10λ0. The overall size of the antenna element is 0.16λ0 × 0.16λ0, and the total size of the MIMO antenna is 0.53λ0 × 0.53λ0, where λ0 is computed at the smallest resonating frequency. The prospective antenna is manufactured, and the experimental results are in agreement with the simulation outcomes.