Publications Repository - Gdańsk University of Technology

In this paper, a simple geometry, planar-structured printed multiple-input-multiple-output (MIMO) antenna utilizing dual circular polarization (CP) is presented. The proposed numerically and experimentally validated design features a fully grounded coplanar waveguide (CPW) and a systematically perturbed feedline radiator. The fringing electric (E) field along the feedline is altered by extruding periodic stubs on each side of the microstrip line extended from a grounded CPW. The different physical size of the stubs on each side, plus a slight offset introduced between the stubs breaks the symmetry of the vector E-fields on both side of the edges. The asymmetric E-field weakens the intensity of the respective magnetic current on the opposite side for a wider spectrum, resulting in a wideband operation. The asymmetric vertical magnetic current along the length of the stubs and the combined current on the horizontal edges yield 90-degree out-of-phase orthogonal field components, radiating circularly polarized waves. The proposed design has the advantage of topological simplicity and ease of polarization sense alteration. Owing to this, the design is implemented in MIMO configuration with each port radiating a different sense of CP. The antenna's simulated and measured -10 dB impedance bandwidth is more than 26.5% ranging from 24.6 GHz to 32.1 GHz frequency. Additionally, the antenna retains an axial ratio (AR) of 3 dB or less from 26 GHz to 31.8 GHz. The peak realized gain (RG) of the antenna is 10.3 dBic with an average value of ~ 9.5 dBic across the bandwidth confirming stable radiation in the broadside direction. At the same time, the envelop correlation coefficient and the diversity gain are about 0.01 and 10 dB, respectively over the operating band.

Authors

• Ubaid Ullah,
• prof. dr inż. Sławomir Kozieł link open in new tab ,
• dr hab. inż. Anna Pietrenko-Dąbrowska link open in new tab ,
• Shahanawaz Kamal