## 5 Results Analysis
### Meta-Atom Array Configurations
#### 5.2.4 4 \(\times\) 4 Array Analysis
To attain the adequate wide bandwidth, multi frequency bands and high performances, the ground plane of the proposed antenna has been replaced by the meta-atoms. Moreover, after replacing the antenna ground plane by the meta-atoms, then the SMA connector is connected with the partial ground integrated with the meta-atoms shown in Figure 14c,d. From Figure 15a, the resonance of the return loss of the meta-atom antenna are respectively at 4.22, 6.30, 7.22, 11.34 and 13.68 GHz, whereas the bandwidth are sequentially 130 MHz (from 4.20 to 4.33 GHz), 120 MHz (from 6.26 to 6.38 GHz), 200 MHz (from 7.10 to 7.30 GHz), 2.17 GHz (from 9.93 to 12.10 GHz) and 0.9 GHz (from 13.10 to 14 GHz). On the contrary, the designed antenna without integrating the meta-atom of the ground plane has the resonance at 5.67 and 7.79 GHz. Therefore, after integrating the proposed meta-atom by replacing the ground plane, the antenna resonance peaks and frequency bands have been improved. In addition, in Figure 15b, from the gain curve, it can also be commented that the antenna with the meta-atom has achieved an average gain of almost 2.85 dB at the resonance bandwidth regions. The maximum peak gain is around 5 dB. Figure 14: The geometry of the: (**a**) antenna transparent 3D view, (**b**) ground plane without integrated meta-atom back view, (**c**) antenna transparent 3D view of integrated meta-atom with ground plane, (**d**) ground plane replaced by integrated meta-atom, back view. Figure 15: Antenna performances: (**a**) return loss (\(S_{11}\)), (**b**) gain; without and with the meta-atom at the ground plane. Table 7 depicts the quality factors of the proposed meta-atom and that reported in [17; 23]. In [17], the sensitivity was 14, and in [23], it was 31; but for the proposed structure, the sensitivity is 82, which is more than the previous one. Besides, for the high quality factor, making of the designed meta-atom is flexible for high-performance filters and sensor applications. Table 8, represents a comparison between the frequency bands and effective medium ratios of the proposed design with the previous design. For the compactness of the meta-atom, an effective medium ratio is an important factor. The proposed meta-atom unit cell exhibits an effective medium ratio (EMR) of 8.50, which is greater than that of the other unit cells. As a result, the designed structure is more suitable and compact in size. Moreover, the proposed meta-atom structure is applicable for S-, C- and Ku-band applications. From Table 9, [PERSON] et al. discussed 1 \(\times\) 2 and 2 \(\times\) 2 arrays at an orthogonal position [16]. [PERSON] et al. presented 2 \(\times\) 2 array structures for double-negative characteristics and multi-band applications [17]. [PERSON] et al. showed a 2 \(\times\) 2 array configuration under open and interconnect conditions. In their framework, they analyzed the effect on resonances by changing the dimensions of the arrays [18]. In this study, the left-handed characteristics, compactness, frequency band and bandwidth of 1 \(\times\) 2, 2 \(\times\) 2, 3 \(\times\) 3 and 4 \(\times\) 4 arrays are analyzed by 0\({}^{\circ}\), 90\({}^{\circ}\), 180\({}^{\circ}\) and 270\({}^{\circ}\) rotations.