Decoupling of Two Closely‐Spaced Planar Monopole Antennas Using Two Novel Printed‐Circuit Structures

Abstract

A new approach is presented in this paper to reduce mutual coupling between two closely‐spaced planar monopole antennas. The approach employs either two parallel metallic strips or a single strip with a meander‐shaped slotted pattern symmetrically placed between the two antennas with their edges being separated by 4 mm and 8 mm, respectively. The novel aspect of our approach is that the decoupling structures are not only confined in the space shared by the two planar monopole edges but are rather extended above the partial ground plane on one end and to the edge of the substrate on the other end. The design provided measured −10 dB impedance and − 20 dB decoupling bandwidths extending from 1.65 GHz to 4 GHz, and 1.43 GHz to 3.7 GHz, respectively, and the measured realized gains at 2.45 GHz are 3.81 dBi and 2.14 dBi, respectively. The proposed arrays offer excellent MIMO performance in terms of envelope correlation coefficient and link efficiency in realistic MIMO propagation environments through the decoupled frequency regimes.

A Review on Different Techniques of Mutual Coupling Reduction Between Elements of Any MIMO Antenna. Part 1: DGSs and Parasitic Structures

“…A central metallic reflector has been placed in the center of two groups of four‐elements of dielectric resonator antennas (DRAs) (Sharawi et al., 2017), as represented in Figure 16b for isolation and tilting the radiation pattern of one group resonating at 5.8 GHz by 45° as compared to another group resonating at 2.45 GHz. Similarly, a simple metallic strip (Roshna et al., 2015), T‐shaped parasitic strip (Kang et al., 2015), a modified interdigital capacitor (Kumar et al., 2018b), a novel ITI‐shaped parasitic structure (Kumar et al., 2019a), parasitic inverted L‐element with an open stub (Lee et al., 2012), H‐shaped strip (Li et al., 2016), floating parasitic decoupling structure (Khan et al., 2014), a rotated “+” shaped rectangular strip pair (Singhal, 2019) as represented in Figure 17a, a rectangular parasitic element is embedded at the substrate backside (Hatami et al., 2019), two separate rectangular shapes and T‐shaped parasitic elements (Faraz et al., 2019), as represented in Figure 17b, cross‐shaped metallic fence (Caizzone, 2017), stepped cross‐shaped reflector strip (Thummaluru et al., 2019), a circular parasitic element at the backside of the radiating patch (Ghimire et al., 2019), a novel reversed S‐shaped walls (Wang et al., 2019), a decoupling metal strip loaded with an inductor (Nie et al., 2019), an optimized parasitic element (Addaci et al., 2012) as represented in Figure 18a, slotted meander‐line resonator (SMLR) (Alsath et al., 2013) as represented in Figure 18b, a simple rectangular parasitic structure at the back (Azarm et al., 2019), diagonal parasitic strip at the back (Chouhan et al., 2019), Minkowski fractal‐shaped isolators (Debnath et al., 2018) as represented in Figure 19a, a complementary pattern (CP) comprised of meandered transmission lines (Hwang et al., 2010), a group of six parasitic elements (Min et al., 2005), as represented in Figure 19b, two parallel strips, or a single strip embedded with patterned meander‐shaped slot (Isaac et al., 2018) as represented in Figures 20a and 20b, two parasitic monopole providing a decoupling path (Li et al., 2012) as represented in Figure 21a, a novel H‐shape parasitic element embedded in the ground plane (Liu et al., 2018) as represented in Figure 21b, a T‐shaped coupling eleme...…”

“…Figure 20. (a) Two parallel metallic strip and (b) single strip embedded with a meander-shaped slot pattern(Isaac et al, 2018).…”

Mutual Coupling Reduction between Two Closely Spaced Antennas with a General PMC Symmetry Plane for Mobile Terminals

“…Another is to eliminate the original coupling surface current by introducing a balancing reverse current. It can be induced by a neutralization microstrip line [15], a parasitic element [16], or a decoupling network [17][18][19][20][21][22][23][24]. Apart from that, there are many other solutions used to eliminate coupling, for instance, selfdecoupled elements [25] and high-order modes [26].…”

The Coefficient of Variation as a Performance Metric of Mimo Antenna Systems Under Arbitrary Handset Orientations

“…The design of antenna arrays for a handset has a significant impact on the MIMO performance of a mobile device [1][2][3][4][5][6]. Designing efficient MIMO antennas for mobile terminals is very challenging due to the influence of user orientation [1,[7][8][9][10][11][12].…”

“…The orientation of a handset antenna has a substantial impact on the interaction of the 3-D radiation patterns with the wireless channel in MIMO systems. The handset performance affects the overall network performance; it also affects the total capacity in the network since end-users with non-optimal handsets operate at lower modulation and coding scheme [1][2][3][4][5][6][7][8][9][10][11][12]. Therefore, industry seeks accurate methods to assess and evaluate the effects of orientation of the handset on the performance in MIMO systems [7].…”