## 7 Results and Discussion  
The numerical simulation of the modified Coptic cross shape-based metamaterial unit cell was executed using a Finite Integration Technique (FIT) based CST simulator. The scattering parameters (\(S_{11}\) and \(S_{21}\)) graph of the proposed unit cell is delineated in Figure 8a. The \(S_{11}\) results of the proposed unit cell provide quadruple resonances with frequencies of 3.085, 8.095, 10.795, and 15.775 GHz with an amplitude of \(-27.03\), \(-13.14\), \(-9.66\), and \(-4.91\) dB; on the other hand, the \(S_{21}\) results exhibit four resonance frequencies at 2.02, 6.985, 9.985, and 14.425 GHz with the magnitude of \(-29.45\), \(-25.44\), \(-19.05\), and \(-24.45\) dB, respectively. The unit cell provides excellent bandwidth for \(S_{21}\) results in the range of 1.815 to 2.202 GHz, 6.415 to 7.335 GHz, 9.658 to 10.208 GHz, and 13.575 to 14.959 GHz. To verify the results, numerical simulation was also performed using a Finite Element Method (FEM) based HFSS simulator. The scattering parameters' results of the proposed unit cell are outlined in Figure 8b. The \(S_{11}\) results of the proposed unit cell contribute four resonances with frequencies of 3.09, 8, 10.76, and 15.46 GHz with an amplitude of  
Figure 7: (**a**) Equivalent circuit model of unit cell. (**b**) S21 plot using CST and ADS simulator. \(-27.04\), \(-13.30\), \(-9.72\), and \(-5.56\) dB; the \(S_{21}\) results show four resonance frequencies at 2.05, 6.97, 9.98, and 14.215 GHz with the magnitude of \(-30.65\), \(-27.26\), \(-20.55\), and \(-25.20\) dB, respectively. From the Figure 8b, it can be seen that the proposed unit cell exhibited quadruple resonances in both simulators with slight fluctuations. To further validate the results, the measurement approach through the fabrication of the unit cell was performed using the Agilent N5227 PNA Microwave Network Analyzer. The measurement prototype was set up between a pair of waveguides. There are four pairs of waveguides used in this measurement process, including 510 WCAS (1.45-2.20 GHz), 137 WCAS (5.85-8.20 GHz), 90 WCAS (8.20-12.4 GHz), and 75 WCAS (10-15 GHz). The prototype and measurement setup of the proposed unit cell and array are shown in Figure 9 a-c. The measured resonance frequencies of \(S_{21}\) are 1.77, 7.181, 9.787, and 14.425 GHz with an amplitude of \(-11.89\), \(-28.45\), \(-20.44\), and \(-33.73\) dB. Figure 9d shows that the measured transmission coefficient (\(S_{21}\)) results (second, third, and fourth) are slightly inconsistent with the simulation results due to vector network analyzer (VNA) calibration errors, waveguide coupling effects, and cable losses. The first resonance frequency of measured results is more varied with simulated results. The proposed metamaterial structure has explored the tunability properties. Smaller Coptic resonator width sizes result in lower annealed copper inclusion, resulting in lower ohmic losses. Meanwhile, a large Coptic width size has several advantages in the attempt to obtain an infinite medium at higher frequency. This indicates that by changing the Coptic width, the metamaterial structure can be tailored for a variety of applications of interest. The influence of the Coptic width of the metamaterial on the transmission coefficient has already been investigated in Figure 5c. The Coptic width size ranges from 0.4 mm to 1 mm. The resonance frequencies shift higher as the Coptic width size increases. A unique characteristic of this structure is that the resonance frequency can be tuned by modifying the sizes of the Coptic width. Selecting the resonance frequency through a tuning process based on the size of the Coptic width makes it more suitable for satellite applications. Figure 8: The graph for (**a**) \(S_{11}\) vs. \(S_{21}\) using CST simulator, (**b**) \(S_{11}\) vs. \(S_{21}\) using CST and HFSS simulator.