Mutual Coupling Reduction of Two PIFAs With a T-Shape Slot Impedance Transformer for MIMO Mobile Terminals

Abstract

An efficient technique is introduced to reduce mutual coupling between two closely spaced PIFAs for MIMO mobile terminals. The proposed mutual coupling reduction method is based on a T-shape slot impedance transformer and can be applied to both single-band and dual-band PIFAs. For the proposed single-band dual PIFAs, the 10 dB impedance bandwidth covers the 2.4 GHz WLAN band (2.4-2.48 GHz), and within the WLAN band an isolation of over 20 dB is achieved. Moreover, the dual-band version covers both the WLAN band and the WiMAX band of 3.4-3.6 GHz, with isolations of over 19.2 dB and 22.8 dB, respectively. The efficiency, gain and radiation patterns of the two-PIFA prototypes are verified in measurements. Due to very low pattern correlation and very good matching and isolation characteristics, the capacity performances are mainly limited by radiation efficiency. The single-band and dual-band PIFAs are also studied with respect to their locations on the ground plane. An eight-fold increase in the bandwidth of one PIFA is achieved, when the single-band PIFAs are positioned at one corner of the ground plane, with the bandwidth of the other PIFA and the good isolation unchanged. Index Terms-Antenna array mutual coupling, MIMO systems, parasitic antennas I. INTRODUCTION ULTIPLE-INPUT and multiple-output (MIMO) technology has become an important feature in all future generation wireless communication systems. This is primarily because it can linearly increase channel capacity with an increase in the number of antennas, without needing additional frequency spectrum or power. Moreover, popular wireless communication systems typically operate in rich scattering environments, which MIMO exploits to achieve the aforesaid large performance gain. However, the requirement for compactness of MIMO-enabled user terminals in mobile communications can potentially induce

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].…”

A Compact Planar Inverted F Antenna Array For Wireless LTE Portable Devices

“…These techniques include the use of defected ground structures, impedance transformers, neutralization lines, parasitic components etc. These techniques try to divert the direction of the surface current flowing on the antenna surface to reduce electromagnetic interaction between antenna elements [5], [6]. The disadvantages of above mentioned techniques are their complex geometry and comparatively large design.…”

Dual Notch Uwb Fork Monopole Antenna With CRLH Metamaterial Load

“…Fork shaped antenna with different formations and parasitic elements such as L-shaped conductor-backed elements are used for UWB applications [11,12]. Microstrip slot antennas with different slot shapes, e.g., T-shape [13], H-shape [14], U-shape and L-shape [14] used to obtain the favorable frequency band notch, have been studied. In addition, fractal and parasitic structures are usual approaches for generating multiple band notched antennas based on CPW or other UWB structures [15].…”