Decoupling between ground radiation antennas with ground‐coupled loop‐type isolator for WLAN applications

Abstract

A compact and easy to fabricate decoupling method is proposed to yield high isolation for the multiple‐input and multiple‐output (MIMO) ground radiation antenna (GradiAnt) system. The proposed MIMO antenna system is comprised of two symmetrical, closely spaced, loop‐type (GradiAnts) with a ground‐coupled loop‐type isolator inserted between them. The isolator can be seen as a series resonant circuit which is connected with lumped components to control decoupling. In the proposed MIMO GradiAnt system, a coupling null is induced due to the ground‐coupled isolator, which effectively can be used for isolation enhancement between two GradiAnts. Within WLAN band, a minimum 14 dB isolation with a peak value of 42 dB at 2.42 GHz is achieved. In this manuscript, the decoupling principle and controlling mechanisms are first explained, then the antenna performances and tuning mechanisms are discussed in detail. The simulation and the measurement of the MIMO antenna, including the scattering parameters, efficiency, radiation patterns, peak gains and envelope correlation coefficients are conducted to verify the performance of the proposed MIMO system.

Mutual Coupling Reduction Using Meta-Structures for Wideband, Dual-Polarized, and High-Density Patch Arrays

“…Also, they include electromagnetic band-gap (EBG) structures, such as mushroom-like EBG structures [8], F-shaped EBG structures [9], and uniplanar compact EBG structures [10,11]. Defected ground structures (DGSs), such as periodic rectangular slits [12], back-to-back U-shaped slots [13], T-shaped slots [14], and loop slots [15] have also been used. More recently, numerous metamaterial-inspired structures have been considered, such as folded single split ring resonators [16], grounded split-ring resonators (GSRRs) [17], multiple split-ring resonators (MSRRs) [18] While the above strategies have reduced mutual coupling, one witnesses certain drawbacks accompanying each of them.…”

“…Also, they include electromagnetic band-gap (EBG) structures, such as mushroom-like EBG structures [8], F-shaped EBG structures [9], and uniplanar compact EBG structures [10,11]. Defected ground structures (DGSs), such as periodic rectangular slits [12], back-to-back U-shaped slots [13], T-shaped slots [14], and loop slots [15] have also been used. More recently, numerous metamaterial-inspired structures have been considered, such as folded single split ring resonators [16], grounded split-ring resonators (GSRRs) [17], multiple split-ring resonators (MSRRs) [18], complementary split-ring resonators (CSRRs) [19], elliptical split-ring resonators (E-SRRs) [20], embedded circuit (EC) resonators [21], capacitively loaded loop (CLL) resonators [22], waveguide-based resonators [23], composite metamaterials [24][25] [26,27], double-layer mushroom structures [28], and coplanar strip walls [29].…”

Compact MIMO antenna for application to smart glasses using T‐shaped ground plane

“…The decoupling theorem of the proposed MIMO antenna system utilizing the T‐shaped ground can be explained using a three‐port network as follows. The two antennas and T‐shaped ground plane are designated as port 1, port 2, and port 3, respectively.…”

“…It is difficult to develop antennas in a compact area while achieving high isolation. Various decoupling methods have been reported for achieving miniaturization and high isolation, including using a neutralization line or an additional decoupling resonator (eg, strip, slot), and the adoption of characteristic mode. However, the antenna structures in the previous studies occupy a large area with additional decoupling structures and ground plane, which is difficult to implement in smart glass applications.…”

Compact wideband MIMO mobile‐antenna system design using mode‐based decoupling techniques

“…In MIMO applications, antenna decoupling is an important factor to ensure high isolation, high efficiency, and low correlation. The normally used techniques include orthogonal polarization, decoupling networks, and additional decoupling structures (decouplers) . In the first method, high isolation and low correlation are achieved by sacrificing one of the antennas, since only one ground mode can support good antenna performance, especially at the lower frequency.…”