Novel Compact Tri-Band Two-Element and Four-Element MIMO Antenna Designs

This paper presents a novel miniaturized tri-band antenna which can be used as a single element or as an element of a compact array in MIMO applications. Specifically, the tri-band MIMO antenna has been constructed and used, in arrays of two and four, in a laptop PCMCIA wireless LAN card. The size of the four element MIMO antenna array is 50 mm times 13 mm times 8 mm which translates to 0.4 lambda times 0.1 lambda times 0.07 lambda at 2.45 GHz. The antenna has a return loss lower than -10 dB in the 2.4 to 2.5 GHz, 5.15 to 5.35 GHz, and 5.7 to 5.85 GHz bands. The total active reflection coefficient (TARC) has been calculated for various combinations of excitations of the two-element and four-element MIMO systems. The antenna was simulated using the Ansoft HFSS. MIMO antenna prototypes have been constructed and measured to demonstrate their functionalities