Connected ground optically transparent wideband MIMO antenna for LTE/UMTS/GSM/Bluetooth and WLAN applications

A connected ground 4-port wideband transparent antenna is proposed. The structure attains optical transparency due to AgHT-8 (Silver Tin Oxide) and Plexiglass. The geometry of a single radiating element consists of a U-shaped patch connected with a semicircular arc and an inverted L that is fed through a microstrip line. The antenna has a full ground plane along the vertical direction and is truncated along the horizontal directions. The antenna geometry is replicated to form three different 4-port MIMO structures where the first one has a separate ground profile while the latter comprises 2 different (O and H shaped) connected ground profiles. The proposed structure is decided after evaluating the isolation levels while achieving the required frequency bands of operation. At the lowest frequency, the antenna size is 0.092λ × 0.165λ. Impedance bandwidth of (121.36%) 0.69–2.82 GHz over a − 10 dB band with isolation better than 20 dB amid all elements is achieved. The antenna is assessed in terms of MIMO diversity, scattering, and transmission parameters by simulating the antenna followed by experimental results which depict a decent correlation. The average gain and efficiency above 0.5 dBi and 40%, respectively with optical transparency, connected ground, satisfactory isolation, and diversity parameters make the transparent 4-port MIMO antenna suitable for GSM (850/900/1800/1900), LTE (700/2300/2500), UMTS (2100), Bluetooth (2400) and WLAN (2400) applications where device aesthetics, location issues, and visual clutter need to be mitigated.