Planar Four-Port Dual Circularly-Polarized MIMO Antenna for Sub-6 GHz Band

Abstract

In this work, two configurations (Config.-A and Config.-B) of planar four-port dual circularlypolarized (CP) multiple-input-multiple-output (MIMO) antenna are proposed for sub-6 GHz (3.4-3.8 GHz) applications. The MIMO antennas are designed on the FR-4 substrate with size of 60×60×1.6 mm 3. Each radiating element (unit cell) of the MIMO antenna is comprised of a microstrip feed line and an open slot ground plane integrated with two rectangular arms for realizing circular polarization. An I-shaped metallic strip is used in the proposed four-port MIMO Config.-A and Config.-B antennas for obtaining common voltage level in the ground plane. Both MIMO antenna configurations exhibit good impedance matching in the band of interest. In the MIMO Config.-A antenna, all ports provide the same CP band, while in the Config.-B antenna the ports-1/-2 and-3/-4 radiate at different CP bands. The proposed MIMO Config.-A and Config.-B antennas support both types of polarization (left-hand circular polarization (LHCP) and right-hand circular polarization (RHCP)). With the Config.-B antenna, the maximum 3-dB axial-ratio (AR) beamwidths of 118.9 • and 92.7 • are obtained at 3.536 GHz in the xz-and yz-planes, respectively. Furthermore, the Ishaped strip helps in improving 3-dB AR beamwidth in the MIMO Config.-B antenna. Inter-element isolation greater than 19 dB and envelope correlation coefficient (ECC) less than 0.12 (far-field) are achieved between the ports of the fabricated MIMO antenna prototype. INDEX TERMS Connected ground, dual circular polarization, four-port, MIMO antenna, planar.

A Design of CP-MIMO System with Elements of a Diamond-Ring Slot for 5G Mobile-Phone

“…The resultant value of VSWR at operating frequency did not exceed 2 dB, which matches its condition according to [16]. The Axial Ratio (AR) is an essential parameter for CP antennas that should not exceed -3dB, as the decision of [11], as shown in Fig. 5.…”

“…Furthermore, CP antennas have recently gained prominence due to their enhanced signal propagation properties as compared to Linearly Polarized (LP) antennas [11]. On the other hand, CP can combine with the orthogonal dual-feed to obtain high isolation [12], so the present study attempts to use such a strategy.…”

3-D twelve-port multi-service diversity antenna for automotive communications

“…The antennas in 7 , 33 , 35 , 47 occupied an equivalent/smaller area but had fewer elements. The proposed MIMO antenna outperforms in terms of ECC, DG, MEG, TARC, and CCL, whereas all of these diversity factors were not investigated in the majority of reported papers 14 , 20 , 33 – 38 , 40 , 41 , 43 – 45 , 47 , 49 , 51 – 55 , 58 , 59 . The housing effect and on-car body performance of the proposed 3-D MIMO antenna are investigated, whereas they were previously studied only for single-element/two-element/2-D MIMO antenna designs 1 , 31 , 32 , 45 , 55 .…”

Four-Port Wideband Circular Polarized MIMO Antenna for Sub-6 GHz Band

“…For CP antennas, AR is an essential parameter that helps to quantify the polarization of an antenna "specify the maximum main beam direction with ; and h values". For antennas have perfect circular polarization AR = 0.37 dB, AR must be less than 3 dB [7], as shown in Fig. 6.…”

“…The polarization can be classified into three types: Circular polarization (CP), linear polarization (LP), and Elliptical polarization (EP) [7]. It is possible to consider both circular and linear polarization as exceptional elliptical polarization cases [8,9].…”