Compact size easily extendable self isolated multi-port multi-band antenna for future 5G high band and sub-THz band applications

This work is focused to develop a novel and compact size multi-port antenna which can operate into multiband characteristics (5G High bands and sub-THz band). The two-port antenna structure is configured in such a way that offered high isolation between the ports without using any decoupling mechanism. Further, this research has explored the methods to extend the two-port antenna configuration into four-port and eight-port while preserving the MIMO performance and multi-band operating behaviour of the antenna. The purpose of antenna configuration extension is to get improved MIMO performance. Initially, two-port antenna evolution is carried out to obtain the desired operating multi-band characteristics. The two-port antenna is developed on small size (150 μm X 200 μm) low-cost RT/duroid 5880 substrate. The antenna is comprised of two parallel arranged pentagon-shaped antenna elements which are fed by the micro-strip feed-line. The antenna impedance bandwidth is achieved by placing the Complementary Ring Resonator (CSRR) structure on both sides of the feed line. Isolation between the ports is enhanced by etching the pentagon-shaped rings in the ground plane of the antenna. Further, two-port antenna is easily extended into four-port and eight-port configuration. Performance evaluation of the extended versions of the antenna is performed in terms of operating bandwidth, isolation, and MIMO parameters (ECC, diversity gain, TARC, CCL). The proposed antennas have offered 24, 28, 37 GHz 5G operating bands as well as 0.035 − 0.2 THz band for high-speed short-range communication applications. The achieved sub-THz band is also very useful for biomedical sensing applications. The MIMO diversity performance parameters of the proposed antenna are Isolation, ECC, diversity gain, TARC, and CCL are obtained as − 30 dB, 0.000046, almost 10,− 35 dB, and 0.027bps/Hz respectively.