Compact 2-Port Wideband MIMO Antenna with Same-Sense Circular Polarization Characteristics

A 2-port wideband compact Multi-Input-Multi-Output (MIMO) antenna with Same-Sense-Circular-Polarization (SSCP) characteristics have been studied. The arrangement of the antenna asserts an elliptic ground configuration with parasitic stubs contorted at 45° to provide good 10-dB impedance matching, reduce mutual coupling and wideband 3-dB axial-ratio bandwidth (ARBW). Simple offset monopole radiating units are placed to excite the slot configured antenna without any supplementary isolation topology. When either port is excited, the antenna offers SSCP waves at principal far-field radiation planes <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varphi=0^{\circ}$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\varphi=90^{\circ}$</tex>. The antenna achieves performance merits with <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\approx 70\%$</tex> 10-dB IBW, 52.5% 3-dB ARBW and port isolation of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$&gt; 17.7\text{dB}$</tex> in the operating range (4.6 - 9.5) GHz. The correlation parameters shows its excellent viability for diversity environments. A prototype antenna of dimension <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$40\text{mm}\times 20\text{mm}$</tex> has been fabricated and the experimental investigation shows its potential for indoor and outdoor wireless systems.