# Dual-Band Wearable Antenna Integrated with Glasses for 5G and Wi-Fi Systems
## 3 Results--Design Verification with the Antenna Prototype  
The prototype antenna was fabricated using flexible, single-sided Pyralux laminate from DuPont (Circleville, OH, USA), a material previously employed by the author for flexible wearable antenna development, demonstrating its suitability for rapid prototyping via chemical etching [23; 24]. The fabricated prototype is depicted in Figure 14 and is fed via a coaxial probe. Due to the very low thickness of the substrate, the antenna is very flexible and easy to fold. To stabilize the plane shape of the antenna, it was placed on a Styrofoam spacer with a thickness of 5 mm. Due to its low density, this material has electrical properties that are very similar to air and does not introduce an impedance mismatch with the antenna. For the comprehensive characterization of the antenna, the prototype, equipped with a Styrofoam spacer, was securely attached to plastic protective glasses using adhesive tape. These glasses were then carefully positioned on a human head phantom, ensuring a consistent 9 mm separation between the antenna's radiating element and the phantom's surface, as visually depicted in Figure 15. The phantom itself was filled with a meticulously prepared tissue-simulating liquid, engineered to emulate the dielectric properties of human tissue at the operational frequency. This liquid exhibited a relative permittivity of 55 and a conductivity of 1.2 S/m at a frequency of 3 GHz and a temperature of 23 \({}^{\circ}\)C.  
Figure 14: Antenna prototype: (**a**) the structure on the laminate, (**b**) the antenna fixed to the Styrofoam spacer. Figure 15: Antenna fixed to the Styrofoam spacer and located on the head phantom for measurements. The precise dielectric properties of this tissue-simulating liquid were determined using a Di-line measurement system, as illustrated in Figure 16. This system has been previously validated and employed by the author for the accurate characterization of liquids utilized in various human body phantom studies, as referenced in [25; 26; 27]. The characterization results, directly obtained from the Di-Line software version 1.0, are systematically presented in Figure 17. Notably, the measured values for the liquid's properties align closely with those reported in the existing literature for comparable tissue-simulant liquid materials [28], thus validating the fidelity of the phantom's dielectric representation. Subsequent measurements of the antenna's impedance and radiation pattern were rigorously performed within an anechoic chamber to mitigate external electromagnetic interference. Figure 15 further illustrates the prototype antenna's mounting on the test stand within this anechoic environment. For radiation pattern measurements, the human head phantom was affixed to a motorized rotor, designed to rotate precisely around a vertical axis. The rotation of this rotor was meticulously controlled by dedicated measurement software, which simultaneously recorded the received power at each angular increment using a FSC6 spectrum analyzer produced by Rohde & Schwarz, Vienna, Austria. This integrated setup allowed for the accurate acquisition of the antenna's far-field radiation characteristics under conditions closely approximating in situ operation. were carried out with the Rohde & Schwarz HF 907 antenna, using the reference antenna method for this purpose. The results of the antenna impedance matching measurements are shown in Figure 18. In this case, the impedance band covers the range from 3.40 GHz to 3.64 GHz and from 5.7 GHz to 6.15 GHz. The antenna radiation pattern was primarily characterized in the horizontal plane, which is a typical and highly relevant orientation for wearable antennas designed to operate on or in close proximity to the human body. Investigating the radiation characteristics in the vertical plane, however, presents additional complexities.