# Dual-Band Wearable Antenna Integrated with Glasses for 5G and Wi-Fi Systems
## 4 Discussion  
The simulation results presented in Figure 9 demonstrate the antenna's capability to achieve dual-band operation, effectively covering the designated frequency bands for both 5G (3.4-3.6 GHz) and Wi-Fi (5.725-5.875 GHz, within the broader 5.61-6 GHz and 5.7-6.05 GHz bandwidths) systems. The consistent impedance bandwidth performance when transitioning from free space to on-body placement in the lower band underscores the antenna's robustness against the detuning effects typically associated with the human body's proximity at these frequencies. However, minor impedance detuning was observed in the higher band upon on-head placement, which, while present, did not compromise the antenna's ability to cover the target Wi-Fi band. This observation aligns with previous studies on wearable antennas, which often report a greater sensitivity to the human body's influence at higher frequencies due to increased dielectric losses and surface wave propagation [29; 30]. The working hypothesis that the antenna design could maintain sufficient bandwidth for both bands even in the presence of the human head is thus largely supported by the simulation data. The simulated radiation patterns, as depicted in Figures 10 and 11, reveal directional characteristics in the horizontal plane with peak gains of 4.8 dBi and 4.3 dBi at the respective 5G and Wi-Fi bands. These gain values suggest a reasonable level of signal transmission and reception capability for wearable applications. Comparing these simulated gains with those achieved in previous research on wearable antennas for similar frequency bands [12; 13; 14; 15; 16; 17; 18; 19], this design demonstrates comparable performance, indicating its potential suitability for practical use cases. The specific absorption rate (SAR) characteristics of the presented antenna design were evaluated, demonstrating its ability to meet human electromagnetic exposure standards. For both designated operating frequencies and at the maximum terminal power levels defined by each standard, the SAR values were found to be below the European Union's recommended limit of 2.0 W/kg. This compliance is essential for ensuring user safety and satisfying regulatory mandates. The measured impedance matching results, illustrated in Figure 18, corroborate the dual-band functionality observed in the simulations. The measured impedance bandwidths (3.40-3.64 GHz and 5.7-6.15 GHz) effectively encompass the target 5G and Wi-Fi bands, exhibiting a slight broadening compared to the simulated results. This discrepancy between the results of measurements and simulations could be attributed to the differences  
Figure 22: Prototype antenna radiation pattern for the on-head location in the horizontal (x-y) plane, horizontal polarization \(G_{\varphi}\) (\(\varphi\), 90°) vs. \(\varphi\) angle, for 5.8 GHz. between the numerical model of the head and the physical phantom that was used for the experiments. Another reason for this could be the fabrication tolerances and the inherent complexities of the physical prototype, including the feeding probe compared to the idealized simulation model. However, the differences do not deteriorate the impedance matching below the assumed values. The measured radiation patterns for linear polarizations (Figures 19-22) show an overall angular distribution of gain that is consistent with the simulated patterns, validating the general radiation characteristics of the antenna. The measured peak gains of 3.6 dBi at 3.5 GHz for horizontal polarization and 4.7 dBi for vertical polarization at 5.8 GHz are slightly lower than their simulated counterparts. These minor discrepancies are likely due to the aforementioned differences between the numerical model and the physical phantom used for measurements.