Circularly polarized four-element wideband MIMO antenna for C-band applications using sinusoidal decoupling structure for isolation and axial ratio enhancement

Abstract

In this research, quad-port wideband MIMO with circular polarization for C-band application is proposed. Following are the key highlights:. • The proposed antenna is a low-profile antenna. • The presented antenna produces the wideband lies between 4.2 to 8.2 GHz. • The antenna achieves port isolation exceeding −23 dB. • The peak gain of the antenna is 7.9dBi recorded at 7.75 GHz, and the average gain of 6.3dBi is achieved over the entire range. • Characteristic mode analysis (CMA) is performed to examine the fundamental current modes that contributes for wideband resonance and Circular polarization. • A novel sinusoidal decoupling structure is employed between the elements to improve the isolation and ARBW. • To ensure the practical compatibility of the proposed antenna, MIMO performance metrics such as ECC (<0.0005), DG (∼10 dB), CCL (<0.3 bits/s/Hz), TARC (<−10 dB), and ME (−0.25) are estimated. The growth in wireless communication demands wider bandwidth, high data rate and immune to signal fading antenna systems. In this article, a circularly polarized (CP), wideband (WB), quad-port Multiple- input- multiple-output (MIMO) antenna is presented. The circularly polarized single element antenna is constructed on a Rogers’s substrate 5880 using C-shaped patch and ground plane with modified cross-shaped slot. The single element antenna is replicated and mirrored to build four-port MIMO. A novel sinusoidal decoupling structure (SDS) is established between the MIMO components to boost isolation and axial ratio. The circularly polarized WB-MIMO has impedance bandwidth (IBW) of 64.5 % (4.2 to 8.2 GHz) and the axial ratio bandwidth (ARBW) of 54.5 % (4.2 to 7.2 GHz).The mirror orientation of MIMO components provides polarization diversity, and SDS helps in achieving healthy isolation of less than -23 dB over the complete bandwidth among themselves. This quad-port offers average radiation efficiency of 96 % and peak gain of 7.9dBi in its spectrum. The fabricated antenna measurement results and the simulated results are compared, both shows good agreement. The results of diversity metrics like <0.0005 ECC, below -10 dB TARC, almost 10 dB DG, <0.3bits/s/Hz CCL and -0.25 dB ME is achieved. The isolation and diversity parameters are within the permissible range that makes this structure well suited for 5 G, satellite, WLAN, and WiMAX applications.

Topics & Concepts