Design and Development of a Triple‐Band MIMO Antenna With Metamaterial for Wearable Applications

A compact triple‐band two‐element symmetric‐meander line textile multiple‐input–multiple‐output (MIMO) antenna (S‐MLTMA) with meta‐material is presented for WBAN/WLAN/ISM/wearable applications. The S‐MLTMA is comprised of two rectangular‐shaped resonators and meander line structures that produce resonances at 2.45 GHz and 5.80 GHz. Under the S‐MLTMA, a dual‐band meta‐material layer operating at 2.45 GHz and 5.80 GHz is introduced. The meta‐material layer consists of six unit cells arranged in an array of 2 × 3. The meta‐material offers circular polarization at 5.80 GHz and improves impedance matching at 4.05 GHz due to the additional current path at this frequency. The designed S‐MLTMA offers an impedance matching bandwidth (S11 ≤ −10 dB) in 2.42–2.57 GHz, 3.98–4.10 GHz, and 5.69–5.88 GHz bands, circular polarization in 5.74–5.85 GHz band, isolation greater than 24.2 dB, envelope correlation coefficient (ECC) < 0.24, diversity gain (DG) ∼ 10.1 dB, total active reflective coefficient (TARC) < −10 dB, and multiplexing efficiency between ±3.0. The peak gains of the antenna at frequencies 2.45 GHz, 4.05 GHz, and 5.80 GHz are 6.11 dBi, 5.81 dBi, and 6.09 dBi, respectively. The proposed antenna is also investigated for different human‐body situations including specific absorption ratio (SAR). The size of the proposed S‐MLTMA is 40.0 mm × 86.0 mm. The proposed antenna could be a good candidate for wearable electronic devices in body area networks due to its small size, all textile layers, easy integration into clothes, and reasonable off‐body and on‐body performances.