ABSTRACT
A small size broadband circularly polarized (CP) two-element multiple-input-multiple-output (MIMO) slot antenna with a very low envelope correlation coefficient (ECC) is proposed for ultra-wideband (UWB) applications. Broadband circular polarization is attained by embedding the identical pair of spiral slots, rectangular slot and grounded-L stub on the I-shaped slot antenna. Isolation is achieved through embedding two different slots between mirrored CP square slot antenna elements. The proposed MIMO antenna provides 58.82% (4.8–8.8 GHz) 3-dB axial ratio bandwidth (ARBW), 138.32% (3.17–17.39 GHz) impedance bandwidth (IBW), and more than 16 dB port isolation over the operating band. The MIMO slot antenna size is 40 × 20 mm2 with a measured peak gain of about 4.41 dBi and efficiency more than 70%. The diversity performance is computed and presented in detail.
Acknowledgments
The authors would like to acknowledge and convey their sincere thanks to the Department of Electronics and Communication Engineering, GWECA Ajmer, Rajasthan, India and Banasthali Vidyapith, Niwai, Tonk, India for providing the necessary facilities of measurement to complete this research work.