Dual Slot Two Element MIMO Antennas for Multi-Band Frequency Agility

A frequency diversity multi-band MIMO antenna is presented in this paper. The 2×1 MIMO antenna consists of two identical radiating elements each having a rectangular slot with a hexagonal slot being placed in the inner conducting element. A 50 Ω microstrip feeding line has been placed on the other side of the substrate and being optimized for impedance matching. Each radiator contains a varactor diode with a variable capacitance characteristic based on the applied inverse biasing voltages that are ranging from 0 – 15 V. The proposed antenna exhibits a quad frequency band of operation (2.32 – 2.44), (2.88 – 3.16), (4.32 – 5.25), and (5.21 – 5.71) GHz with the ability to tune the center frequency within each band based on the varactor biasing voltage. Several parameters have been investigated such as the diversity gain (DG), ECC for an efficient view of MIMO features.