Coupling Reduction in Two by Two MIMO Vivaldi Antennas For Full Duplex Applications

In this paper, a two by two Multiple Input Multiple Output (MIMO) Vivaldi antenna has been designed, simulated, fabricated, tested and results compared. The antenna is designed to operate at 3.5 GHz with a bandwidth of $700 \mathrm{MHz}(20 \%)$. The proposed antenna has a gain of approximately 8dB. High isolation up to 70 dB between transmit and receive antennas is achieved by using cross polarization and spatial separation between antennas. Two horizontally polarized (HP) antennas are used for transmitting and two vertically polarized (VP) antennas are used for receiving. The antenna structure is simple and easy to fabricate. The proposed antenna is an excellent candidate for full duplex (FD) and fifth generation (5G) applications.